Acoustic material and preparation method and application thereof

Abstract

The invention relates to an acoustic material as well as a preparation method and application thereof. The acoustic material comprises a first rubber layer, a middle layer and a second rubber layer which are sequentially stacked, the middle layer comprises a first middle layer or a second middle layer; the first middle layer comprises a polyurethane foam layer and a reinforced rubber layer which are stacked; the second middle layer comprises a first reinforced rubber layer, a polyurethane foam layer and a second reinforced rubber layer which are sequentially stacked; and the polyurethane foam layer is obtained by carrying out hot pressing on thermosetting polyurethane foam. Through structural and material design, the acoustic material provided by the invention has the characteristics of good reliability, low density, good mechanical property, good hydrolysis resistance and good aging resistance, and can be used as a material of a folding ring.

Description

Technical Field

[0001] The present invention belongs to the technical field of acoustic materials, and in particular relates to an acoustic material and a preparation method and application thereof. Background Art

[0002] Polyurethane (PU) foam surrounds offer the advantages of low mass and density, resulting in higher sensitivity and sound pressure levels when used in speakers. They also have a low glass transition temperature and excellent resistance to dynamic ozone aging, making them commonly used in automotive subwoofers. PU foam is generally divided into polyester and polyether types. Polyester PU foam is susceptible to hydrolysis in high temperature and humidity, resulting in a shorter lifespan. While polyether PU foam has improved hydrolysis resistance, its resistance to thermal and photooxidative aging is inferior to that of traditional rubber surrounds. Furthermore, PU foam has lower strength and modulus, limiting its application.

[0003] Rubber offers excellent hydrolysis resistance, good compliance, and fatigue resistance, and generally better aging resistance than PU foam. However, its higher density increases the mass of the vibration system. Foamed rubber is typically foamed using chemical blowing agents, and the process is relatively repetitive. This results in poor mechanical properties when producing thinner folds, and poor product uniformity limits its use.

[0004] CN202818581U discloses a rubber-rimmed wooden cone for loudspeakers, which consists of a rubber rim and a wooden cone. The wooden cone is arranged on the upper part of the rubber rim, and the wooden cone and the rubber rim are composited by glue. The main raw material used in the rubber rim is nitrile rubber, which is made by copolymerizing butadiene and acrylonitrile and is formed by hot pressing. CN107286409A discloses a rim, which includes an arc-shaped portion, a first connecting portion extending inward from the inner edge of the arc-shaped portion, and a second connecting portion extending outward from the outer edge of the arc-shaped portion, wherein the rim is made of a rubber compound, and the rubber compound includes styrene-butadiene rubber and a vulcanizing agent. CN202269007U discloses a PU-rimmed PP cone for loudspeakers, which is mainly made of a thermoplastic polyurethane elastomer polymer material and is processed by a vacuum forming process. However, existing folding rings generally have the defects of poor reliability, high density, poor mechanical properties, and poor hydrolysis resistance and aging resistance. There is an urgent need to design an acoustic material that has good reliability, low density, good mechanical properties, good hydrolysis resistance, good aging resistance and can be applied to folding rings. Summary of the Invention

[0005] In view of the shortcomings of the existing technology, the purpose of the present invention is to provide an acoustic material and its preparation method and application. Through the design of structure and materials, the acoustic material has the characteristics of good reliability, low density, good mechanical properties, good hydrolysis resistance and good aging resistance, and can be used as the material of the folding ring.

[0006] To achieve this object, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides an acoustic material, comprising a first rubber layer, an intermediate layer, and a second rubber layer stacked in sequence; the intermediate layer comprises a first intermediate layer or a second intermediate layer; the first intermediate layer comprises a polyurethane foam layer and a reinforced rubber layer stacked in sequence; the second intermediate layer comprises a first reinforced rubber layer, a polyurethane foam layer, and a second reinforced rubber layer stacked in sequence; the polyurethane foam layer is obtained by hot pressing thermosetting polyurethane foam.

[0008] The acoustic material provided by the present invention has a reinforced rubber layer arranged on at least one surface of the polyurethane foam layer, and a first rubber layer and a second rubber layer that are not easily hydrolyzed are respectively arranged on the two surfaces of the intermediate layer, so that the hydrolysis resistance and UV aging resistance of the acoustic material are effectively improved, and the tensile strength and elongation at break are further improved, thereby improving the reliability of the material.

[0009] In the first intermediate layer of the present invention, the surface of the polyurethane foam layer away from the reinforced rubber layer can be bonded to the first rubber layer or the second rubber layer; in the second intermediate layer, the surface of the first reinforced rubber layer away from the polyurethane foam layer can be bonded to the first rubber layer or the second rubber layer.

[0010] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. Through the following preferred technical solutions, the objectives and beneficial effects of the present invention can be better achieved and realized.

[0011] As a preferred technical solution, the density of the acoustic material is 0.7-0.9 g / cm 3 , for example, it can be 0.72g / cm 3 , 0.74g / cm 3 , 0.76g / cm 3 , 0.78g / cm 3 , 0.8g / cm 3 , 0.82g / cm 3 , 0.84g / cm 3 , 0.86g / cm 3 , 0.88g / cm 3 wait.

[0012] The acoustic material provided by the present invention has a low density and can effectively reduce the mass of the vibration system.

[0013] Preferably, the thermosetting polyurethane foam includes polyether-type thermosetting polyurethane foam or polyester-type thermosetting polyurethane foam.

[0014] In the present invention, the polyether-type thermosetting polyurethane foam or the polyester-type thermosetting polyurethane foam can be partially softened under high temperature and high pressure, thereby undergoing slight shape reshaping while retaining the foaming structure.

[0015] Preferably, the density of the thermosetting polyurethane foam is 20-150 kg / m 3 , for example, it can be 25kg / m 3 、30kg / m 3 、35kg / m 3 , 40kg / m 3 , 45kg / m 3 , 50kg / m 3 , 55kg / m 3 , 60kg / m 3 、65kg / m 3 , 70kg / m 3 , 75kg / m 3 、80kg / m 3 、85kg / m 3 , 90kg / m 3 , 95kg / m 3 , 100kg / m 3 、105kg / m 3 、110kg / m 3 、115kg / m 3 , 120kg / m 3 、125kg / m 3 、130kg / m 3 、135kg / m 3 、140kg / m 3 、145kg / m 3 wait.

[0016] Preferably, the thickness of the thermosetting polyurethane foam is 8-15 mm, for example, it can be 8.5 mm, 9 mm, 9.5 mm, 10 mm, 10.5 mm, 11 mm, 11.5 mm, 12 mm, 12.5 mm, 13 mm, 13.5 mm, 14 mm, 14.5 mm, etc.

[0017] Preferably, the hot pressing temperature is 200-230°C, for example, 202°C, 205°C, 208°C, 210°C, 212°C, 215°C, 218°C, 220°C, 222°C, 225°C, 228°C, etc.

[0018] Preferably, the hot pressing pressure is 0.2-0.5 MPa, for example, it can be 0.22 MPa, 0.25 MPa, 0.28 MPa, 0.3 MPa, 0.32 MPa, 0.35 MPa, 0.38 MPa, 0.4 MPa, 0.42 MPa, 0.45 MPa, 0.48 MPa, etc.

[0019] Preferably, the hot pressing time is 40-100s, for example, it can be 45s, 50s, 55s, 60s, 65s, 70s, 75s, 80s, 85s, 90s, 95s, etc.

[0020] Preferably, the thickness of the polyurethane foam layer is 0.2-0.6 mm, for example, it can be 0.22 mm, 0.25 mm, 0.28 mm, 0.3 mm, 0.32 mm, 0.35 mm, 0.38 mm, 0.4 mm, 0.42 mm, 0.45 mm, 0.48 mm, 0.5 mm, 0.52 mm, 0.55 mm, 0.58 mm, etc.

[0021] Preferably, the raw materials for preparing the reinforced rubber layer, the first reinforced rubber layer and the second reinforced rubber layer independently include raw rubber, a first mixed solvent, a first special resin, fiber, a first vulcanizing agent, zinc stearate, a first accelerator and zinc oxide.

[0022] Preferably, the raw materials for preparing the reinforced rubber layer, the first reinforced rubber layer and the second reinforced rubber layer independently include the following components in parts by weight:

[0023]

[0024] The raw rubber is 80-100 parts by weight, for example, 82 parts by weight, 84 parts by weight, 86 parts by weight, 88 parts by weight, 90 parts by weight, 92 parts by weight, 94 parts by weight, 96 parts by weight, 98 parts by weight, etc.

[0025] The first mixed solvent is 400-650 parts by weight, for example, it can be 420 parts by weight, 440 parts by weight, 460 parts by weight, 480 parts by weight, 500 parts by weight, 520 parts by weight, 540 parts by weight, 560 parts by weight, 580 parts by weight, 600 parts by weight, 620 parts by weight, 640 parts by weight, etc.

[0026] The first special resin is 5-15 parts by weight, for example, it can be 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, 8.5 parts by weight, 9 parts by weight, 9.5 parts by weight, 10 parts by weight, 10.5 parts by weight, 11 parts by weight, 11.5 parts by weight, 12 parts by weight, 12.5 parts by weight, 13 parts by weight, 13.5 parts by weight, 14 parts by weight, 14.5 parts by weight, etc.

[0027] The fiber accounts for 10-30 parts by weight, for example, 12 parts by weight, 14 parts by weight, 16 parts by weight, 18 parts by weight, 20 parts by weight, 22 parts by weight, 24 parts by weight, 26 parts by weight, 28 parts by weight, etc.

[0028] The first vulcanizing agent is 0.5-2 parts by weight, for example, 0.6 parts by weight, 0.8 parts by weight, 1 part by weight, 1.2 parts by weight, 1.4 parts by weight, 1.6 parts by weight, 1.8 parts by weight, etc.

[0029] The zinc stearate content in the raw materials for preparing the reinforced rubber layer, the first reinforced rubber layer and the second reinforced rubber layer is independently 0.5-2 parts by weight, for example, 0.6 parts by weight, 0.8 parts by weight, 1 part by weight, 1.2 parts by weight, 1.4 parts by weight, 1.6 parts by weight, 1.8 parts by weight, etc.

[0030] The first accelerator is 2-4 parts by weight, for example, 2.2 parts by weight, 2.4 parts by weight, 2.6 parts by weight, 2.8 parts by weight, 3 parts by weight, 3.2 parts by weight, 3.4 parts by weight, 3.6 parts by weight, 3.8 parts by weight, etc.

[0031] The zinc oxide content in the raw materials for preparing the reinforced rubber layer, the first reinforced rubber layer and the second reinforced rubber layer is independently 3-6 parts by weight, for example, 3.2 parts by weight, 3.4 parts by weight, 3.6 parts by weight, 3.8 parts by weight, 4 parts by weight, 4.2 parts by weight, 4.4 parts by weight, 4.6 parts by weight, 4.8 parts by weight, 5 parts by weight, 5.2 parts by weight, 5.4 parts by weight, 5.6 parts by weight, 5.8 parts by weight, etc.

[0032] Preferably, the rubber raw rubber includes any one of EPDM rubber raw rubber, butadiene rubber raw rubber, chloroprene rubber raw rubber, nitrile rubber raw rubber, butyl rubber raw rubber, styrene-butadiene rubber raw rubber, natural rubber raw rubber or isoprene rubber raw rubber, or a combination of at least two of them.

[0033] Preferably, the first mixed solvent includes a combination of a first aromatic solvent and a first aliphatic solvent.

[0034] Preferably, the first aromatic solvent includes any one of benzene, toluene or xylene, or a combination of at least two of them.

[0035] Preferably, the first aliphatic solvent includes any one of n-pentane, n-hexane, cyclohexane or n-heptane, or a combination of at least two thereof.

[0036] Preferably, the mass ratio of the first aromatic solvent to the first aliphatic solvent is (0.1-0.5):1, for example, it can be 0.15:1, 0.2:1, 0.25:1, 0.3:1, 0.35:1, 0.4:1, 0.45:1, etc.

[0037] The aliphatic solvent of the present invention mainly dissolves the raw rubber and the non-polar additives, while the aromatic solvent dissolves other polar additives.

[0038] Preferably, the first specialty resin includes any one of hydrogenated rosin resin, disproportionated rosin, polymerized rosin, maleated rosin, rosin ester, modified rosin ester or rosin-based phenolic resin, or a combination of at least two thereof.

[0039] The above rosin resin has high viscosity at high temperature, which can better bond with the polyurethane foam layer during the rubber vulcanization process without the risk of delamination.

[0040] Preferably, the fiber includes any one of polyester fiber, vinylon fiber, rayon fiber, aramid fiber, carbon fiber, glass fiber or metal fiber, or a combination of at least two thereof.

[0041] Preferably, the length of the fiber is 3-5 mm, for example, it can be 3.2 mm, 3.4 mm, 3.6 mm, 3.8 mm, 4 mm, 4.2 mm, 4.4 mm, 4.6 mm, 4.8 mm, etc.

[0042] Preferably, the aspect ratio of the fiber is (100-200):1, for example, it can be 105:1, 110:1, 115:1, 120:1, 125:1, 130:1, 135:1, 140:1, 145:1, 150:1, 155:1, 160:1, 165:1, 170:1, 175:1, 180:1, 185:1, 190:1, 195:1, etc.

[0043] Preferably, the first vulcanizing agent comprises sulfur.

[0044] Preferably, the first accelerator comprises tetramethylthiuram disulfide.

[0045] Preferably, the raw materials for preparing the reinforced rubber layer, the first reinforced rubber layer and the second reinforced rubber layer further independently include a first reinforcing agent and / or a first antioxidant.

[0046] Preferably, the first reinforcing agent includes fumed silica.

[0047] Preferably, the first antioxidant includes 2-mercaptobenzimidazole.

[0048] Preferably, the first reinforcing agent in the raw materials for preparing the reinforced rubber layer, the first reinforced rubber layer and the second reinforced rubber layer is independently 20-60 parts by weight, for example, it can be 22 parts by weight, 25 parts by weight, 28 parts by weight, 30 parts by weight, 32 parts by weight, 35 parts by weight, 38 parts by weight, 40 parts by weight, 42 parts by weight, 45 parts by weight, 48 parts by weight, 50 parts by weight, 52 parts by weight, 55 parts by weight, 58 parts by weight, etc.

[0049] Preferably, the first antioxidant in the raw materials for preparing the reinforced rubber layer, the first reinforced rubber layer and the second reinforced rubber layer is independently 1-2 parts by weight, for example, it can be 1.1 parts by weight, 1.2 parts by weight, 1.3 parts by weight, 1.4 parts by weight, 1.5 parts by weight, 1.6 parts by weight, 1.7 parts by weight, 1.8 parts by weight, 1.9 parts by weight, etc.

[0050] Preferably, the thickness of the reinforced rubber layer, the first reinforced rubber layer and the second reinforced rubber layer are each independently 80-200 μm, for example, 90 μm, 100 μm, 110 μm, 120 μm, 130 μm, 140 μm, 150 μm, 160 μm, 170 μm, 180 μm, 190 μm, etc.

[0051] Preferably, the mixing method of the raw materials for preparing the reinforced rubber layer, the first reinforced rubber layer and the second reinforced rubber layer comprises the following steps:

[0052] (S1) mixing raw rubber and a first mixed solvent to obtain a first solution;

[0053] (S2) mixing the first solution, the first special resin, the first vulcanizing agent, zinc stearate, the first accelerator, and zinc oxide to obtain a second solution;

[0054] (S3) The second solution is mixed with fibers to obtain the reinforced rubber layer, the raw material for preparing the first reinforced rubber layer, or the raw material for preparing the second reinforced rubber layer.

[0055] Preferably, the mixing time in step (S1) is 2-5 h, for example, it can be 2.2 h, 2.4 h, 2.6 h, 2.8 h, 3 h, 3.2 h, 3.4 h, 3.6 h, 3.8 h, 4 h, 4.2 h, 4.4 h, 4.6 h, 4.8 h, etc.

[0056] Preferably, the mixing time in step (S2) and the mixing time in step (S3) are each independently 10-30 min, for example, 12 min, 14 min, 16 min, 18 min, 20 min, 22 min, 24 min, 26 min, 28 min, etc.

[0057] Preferably, the temperatures of the mixing in step (S1), the mixing in step (S2) and the mixing in step (S3) are each independently 50-70°C, for example, 52°C, 54°C, 56°C, 58°C, 60°C, 62°C, 64°C, 66°C, 68°C, etc.

[0058] Preferably, the mixing in step (S1), the mixing in step (S2) and the mixing in step (S3) are all carried out under stirring, and the stirring speed is independently 400-600r / min, for example, it can be 420r / min, 440r / min, 460r / min, 480r / min, 500r / min, 520r / min, 540r / min, 560r / min, 580r / min, etc.

[0059] Preferably, the mixed materials in step (S2) further include a first antioxidant.

[0060] Preferably, the mixed material in step (S3) further includes a first reinforcing agent.

[0061] Preferably, after the mixing in step (S3) is completed, the process further includes the steps of first mixing and first degassing.

[0062] Preferably, the first mixing is carried out under stirring conditions, and the stirring speed is 1000-1300r / min, for example, it can be 1020r / min, 1040r / min, 1060r / min, 1080r / min, 1100r / min, 1120r / min, 1140r / min, 1160r / min, 1180r / min, 1200r / min, 1220r / min, 1240r / min, 1260r / min, 1280r / min, etc.

[0063] Preferably, the first mixing time is 5-10 min, for example, 5.5 min, 6 min, 6.5 min, 7 min, 7.5 min, 8 min, 8.5 min, 9 min, 9.5 min, etc.

[0064] Preferably, the first degassing time is 1-3 min, for example, it can be 1.2 min, 1.4 min, 1.6 min, 1.8 min, 2 min, 2.2 min, 2.4 min, 2.6 min, 2.8 min, etc.

[0065] Preferably, the raw materials for preparing the first rubber layer and the second rubber layer independently include EPDM raw rubber, a second mixed solvent, a second special resin, a second vulcanizing agent, zinc stearate, a second accelerator and zinc oxide.

[0066] Preferably, the raw materials for preparing the first rubber layer and the second rubber layer independently include the following components in parts by weight:

[0067]

[0068] The raw materials for preparing the first rubber layer and the second rubber layer each independently contain 80-100 parts by weight of EPDM raw rubber, for example, 82 parts by weight, 84 parts by weight, 86 parts by weight, 88 parts by weight, 90 parts by weight, 92 parts by weight, 94 parts by weight, 96 parts by weight, 98 parts by weight, etc.

[0069] The second mixed solvent is 400-650 parts by weight, for example, it can be 420 parts by weight, 440 parts by weight, 460 parts by weight, 480 parts by weight, 500 parts by weight, 520 parts by weight, 540 parts by weight, 560 parts by weight, 580 parts by weight, 600 parts by weight, 620 parts by weight, 640 parts by weight, etc.

[0070] The second special resin is 5-15 parts by weight, for example, it can be 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, 8.5 parts by weight, 9 parts by weight, 9.5 parts by weight, 10 parts by weight, 10.5 parts by weight, 11 parts by weight, 11.5 parts by weight, 12 parts by weight, 12.5 parts by weight, 13 parts by weight, 13.5 parts by weight, 14 parts by weight, 14.5 parts by weight, etc.

[0071] The second vulcanizing agent is 0.5-2 parts by weight, for example, 0.6 parts by weight, 0.8 parts by weight, 1 part by weight, 1.2 parts by weight, 1.4 parts by weight, 1.6 parts by weight, 1.8 parts by weight, etc.

[0072] The raw materials for preparing the first rubber layer and the second rubber layer each independently contain 0.5-2 parts by weight of zinc stearate, for example, 0.6 parts by weight, 0.8 parts by weight, 1 part by weight, 1.2 parts by weight, 1.4 parts by weight, 1.6 parts by weight, 1.8 parts by weight, etc.

[0073] The second accelerator is 2-4 parts by weight, for example, 2.2 parts by weight, 2.4 parts by weight, 2.6 parts by weight, 2.8 parts by weight, 3 parts by weight, 3.2 parts by weight, 3.4 parts by weight, 3.6 parts by weight, 3.8 parts by weight, etc.

[0074] The zinc oxide content in the raw materials for preparing the first rubber layer and the second rubber layer is independently 3-6 parts by weight, for example, 3.2 parts by weight, 3.4 parts by weight, 3.6 parts by weight, 3.8 parts by weight, 4 parts by weight, 4.2 parts by weight, 4.4 parts by weight, 4.6 parts by weight, 4.8 parts by weight, 5 parts by weight, 5.2 parts by weight, 5.4 parts by weight, 5.6 parts by weight, 5.8 parts by weight, etc.

[0075] Preferably, the second specialty resin includes any one of hydrogenated rosin resin, disproportionated rosin, polymerized rosin, maleated rosin, rosin ester, modified rosin ester or rosin-based phenolic resin, or a combination of at least two thereof.

[0076] Preferably, the second mixed solvent comprises a combination of a second aromatic solvent and a second aliphatic solvent.

[0077] Preferably, the second aromatic solvent includes any one of benzene, toluene or xylene, or a combination of at least two of them.

[0078] Preferably, the second aliphatic solvent includes any one of n-pentane, n-hexane, cyclohexane or n-heptane, or a combination of at least two thereof.

[0079] Preferably, the mass ratio of the second aromatic solvent to the second aliphatic solvent is (0.1-0.5):1, for example, it can be 0.15:1, 0.2:1, 0.25:1, 0.3:1, 0.35:1, 0.4:1, 0.45:1, etc.

[0080] Preferably, the second vulcanizing agent comprises sulfur.

[0081] Preferably, the second accelerator comprises a combination of tetramethylthiuram disulfide, 2-mercaptobenzothiazole, dipentamethylenethiuram tetrasulfide and tellurium diethyldithiocarbamate.

[0082] Preferably, the mass ratio of tetramethylthiuram disulfide, 2-mercaptobenzothiazole, dipentamethylenethiuram tetrasulfide and tellurium diethyldithiocarbamate in the second accelerator is (1-1.2):(3-6):(1-1.2):(1-1.2), for example, it can be 1:3:1:1, 1:3.5:1:1, 1:4:1:1, 1:4.5:1:1, 1:5:1:1, 1:5.5:1:1, 1:6:1:1, 1.1:3:1.1:1.1, 1.1:3.5:1.1: 1.1, 1.1:4:1.1:1.1, 1.1:4.5:1.1:1.1, 1.1:5:1.1:1.1, 1.1:5.5:1.1:1.1, 1.1:6:1.1:1.1, 1.2:3:1.2:1.2, 1.2:3.5:1.2:1.2, 1.2:4:1.2:1.2, 1.2:4.5:1.2:1.2, 1.2:5:1.2:1.2, 1.2:5.5:1.2:1.2, 1.2:6:1.2:1.2, etc.

[0083] Preferably, the raw materials for preparing the first rubber layer and the second rubber layer further independently include any one of a second reinforcing agent, a filling material or a second antioxidant, or a combination of at least two of them.

[0084] Preferably, the second reinforcing agent includes fumed silica.

[0085] Preferably, the filler material comprises ground calcium carbonate and / or calcined kaolin.

[0086] Preferably, the second antioxidant includes 2-mercaptobenzimidazole.

[0087] Preferably, the second reinforcing agent in the raw materials for preparing the first rubber layer and the second rubber layer is independently present in an amount of 20-60 parts by weight, for example, 22 parts by weight, 25 parts by weight, 28 parts by weight, 30 parts by weight, 32 parts by weight, 35 parts by weight, 38 parts by weight, 40 parts by weight, 42 parts by weight, 45 parts by weight, 48 parts by weight, 50 parts by weight, 52 parts by weight, 55 parts by weight, 58 parts by weight, etc.

[0088] Preferably, the filling material in the raw materials for preparing the first rubber layer and the second rubber layer is independently 10-50 parts by weight, for example, it can be 12 parts by weight, 15 parts by weight, 18 parts by weight, 20 parts by weight, 22 parts by weight, 25 parts by weight, 28 parts by weight, 30 parts by weight, 32 parts by weight, 35 parts by weight, 38 parts by weight, 40 parts by weight, 42 parts by weight, 45 parts by weight, 48 parts by weight, etc.

[0089] Preferably, the second antioxidant in the raw materials for preparing the first rubber layer and the second rubber layer is independently 1-2 parts by weight, for example, it can be 1.1 parts by weight, 1.2 parts by weight, 1.3 parts by weight, 1.4 parts by weight, 1.5 parts by weight, 1.6 parts by weight, 1.7 parts by weight, 1.8 parts by weight, 1.9 parts by weight, etc.

[0090] Preferably, the mixing method of the raw materials for preparing the first rubber layer and the second rubber layer comprises the following steps:

[0091] (F1) mixing EPDM raw rubber and a second mixed solvent to obtain a third solution;

[0092] (F2) The third solution, the second special resin, the second vulcanizing agent, zinc stearate, the second accelerator and zinc oxide are mixed to obtain a raw material for preparing the first rubber layer or a raw material for preparing the second rubber layer.

[0093] Preferably, the mixing time in step (F1) is 2-5 h, for example, it can be 2.2 h, 2.4 h, 2.6 h, 2.8 h, 3 h, 3.2 h, 3.4 h, 3.6 h, 3.8 h, 4 h, 4.2 h, 4.4 h, 4.6 h, 4.8 h, etc.

[0094] Preferably, the mixing time in step (F2) is 10-60 min, for example, it can be 12 min, 14 min, 16 min, 18 min, 20 min, 22 min, 24 min, 26 min, 28 min, 30 min, 35 min, 40 min, 45 min, 50 min, 55 min, etc.

[0095] Preferably, the mixing temperature in step (F1) and step (F2) is independently 50-70°C, for example, 52°C, 54°C, 56°C, 58°C, 60°C, 62°C, 64°C, 66°C, 68°C, etc.

[0096] Preferably, the mixing in step (F1) and the mixing in step (F2) are both carried out under stirring, and the stirring speed is independently 400-600 r / min, for example, it can be 420 r / min, 440 r / min, 460 r / min, 480 r / min, 500 r / min, 520 r / min, 540 r / min, 560 r / min, 580 r / min, etc.

[0097] Preferably, the mixed material in step (F2) further comprises any one of a second antioxidant, a second reinforcing agent or a filling material, or a combination of at least two thereof.

[0098] Preferably, after the mixing in step (F2) is completed, the method further comprises the steps of second mixing and second degassing.

[0099] Preferably, the second mixing is carried out under stirring conditions, and the stirring speed is 1000-1300r / min, for example, it can be 1020r / min, 1040r / min, 1060r / min, 1080r / min, 1100r / min, 1120r / min, 1140r / min, 1160r / min, 1180r / min, 1200r / min, 1220r / min, 1240r / min, 1260r / min, 1280r / min, etc.

[0100] Preferably, the second mixing time is 5-10 min, for example, 5.5 min, 6 min, 6.5 min, 7 min, 7.5 min, 8 min, 8.5 min, 9 min, 9.5 min, etc.

[0101] Preferably, the second degassing time is 1-3 min, for example, it can be 1.2 min, 1.4 min, 1.6 min, 1.8 min, 2 min, 2.2 min, 2.4 min, 2.6 min, 2.8 min, etc.

[0102] Preferably, the thickness of the first rubber layer and the second rubber layer are independently 80-200 μm, for example, 90 μm, 100 μm, 110 μm, 120 μm, 130 μm, 140 μm, 150 μm, 160 μm, 170 μm, 180 μm, 190 μm, etc.

[0103] In a second aspect, the present invention provides a method for preparing the acoustic material according to the first aspect, the method comprising the following steps:

[0104] (1) hot pressing the thermosetting polyurethane foam to obtain a polyurethane foam layer;

[0105] (2) coating the raw materials for preparing the reinforcing rubber layer on any one surface of the polyurethane foam layer, or coating the raw materials for preparing the first reinforcing rubber layer and the raw materials for preparing the second reinforcing rubber layer on both surfaces of the polyurethane foam layer, respectively, to obtain a prefabricated intermediate layer;

[0106] (3) coating the raw materials for preparing the first rubber layer and the raw materials for preparing the second rubber layer on both surfaces of the prefabricated intermediate layer, respectively, to obtain a composite material;

[0107] (4) After the composite material is formed, the acoustic material is obtained.

[0108] Preferably, the molding temperature is 160-190°C, for example, 162°C, 165°C, 168°C, 170°C, 172°C, 175°C, 178°C, 180°C, 182°C, 185°C, 188°C, etc.

[0109] Preferably, the molding time is 100-200 s, for example, it can be 110 s, 120 s, 130 s, 140 s, 150 s, 160 s, 170 s, 180 s, 190 s, etc.

[0110] Preferably, the molding pressure is 0.15-0.35 MPa, for example, it can be 0.16 MPa, 0.18 MPa, 0.2 MPa, 0.22 MPa, 0.24 MPa, 0.26 MPa, 0.28 MPa, 0.3 MPa, 0.32 MPa, 0.34 MPa, etc.

[0111] In a third aspect, the present invention provides a fold ring, wherein the material of the fold ring includes the acoustic material as described in the first aspect.

[0112] In a fourth aspect, the present invention provides a sound-generating device, comprising the folding ring as described in the third aspect.

[0113] Preferably, the sound-generating device comprises a loudspeaker.

[0114] The numerical range described in the present invention includes not only the point values ​​listed above, but also any point values ​​between the above numerical ranges that are not listed. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0115] Compared with the prior art, the present invention has the following beneficial effects:

[0116] The acoustic material provided by the present invention has a relatively low density of 0.784-0.861 g / cm 3 ; Good mechanical properties, including tensile strength of 10.2-12.4MPa and elongation at break of 281-386%; good hydrolysis resistance, after boiling in 90℃ hot water for 15 days, the tensile strength attenuation rate is 11-15.3%, and the elongation at break attenuation rate is 14.2-18.3%; good UV aging resistance, after 72h of UV aging, the tensile strength attenuation rate is 8.75-15.4%, the tensile modulus attenuation rate is 7.42-16.5%, and the elongation at break attenuation rate is 14.8-19.2%. DETAILED DESCRIPTION

[0117] For the convenience of understanding the present invention, the present invention is given below with examples. It should be understood by those skilled in the art that the examples are only for the purpose of helping to understand the present invention and should not be regarded as specific limitations of the present invention.

[0118] The sources of some components in the following examples and comparative examples are as follows:

[0119] (1) Raw rubber

[0120] EPDM raw rubber, purchased from ARLANXEO 2650C;

[0121] NBR raw rubber, purchased from Lanzhou Petrochemical 3305E;

[0122] SBR raw rubber, purchased from Lanzhou Petrochemical 1502;

[0123] IIR raw rubber, Bromobutyl 2244 purchased from ExxonMobil, USA;

[0124] (2) Special resins

[0125] Hydrogenated rosin resin, AX-E purchased from Shenzhen Jitian Chemical Co., Ltd.;

[0126] 138# rosin resin, purchased from Shenzhen Jitian Chemical Co., Ltd.;

[0127] 422# rosin resin, purchased from Shenzhen Jitian Chemical Co., Ltd.;

[0128] (3) Thermosetting polyurethane foam

[0129] Polyether thermosetting polyurethane foam A, TM-20 purchased from Inoue Polymer Materials Co., Ltd., with a density of 20 kg / m 3 ;

[0130] Polyether thermosetting polyurethane foam B, TM-150 purchased from Inoue Polymer Materials Co., Ltd., with a density of 150 kg / m 3 ;

[0131] Polyester thermosetting polyurethane foam, TM-80 purchased from Inoue Polymer Materials Co., Ltd., with a density of 80 kg / m 3 ;

[0132] (4) Fumed silica: purchased from Zhuzhou Xinglong New Materials Co., Ltd.

[0133] (5) Fiber

[0134] Chopped aramid fibers were purchased from DuPont, USA, with a fiber length of 3 mm and an aspect ratio of 200:1;

[0135] Chopped carbon fiber, purchased from Mitsubishi Chemical, with a fiber length of 3 mm and an aspect ratio of 120:1;

[0136] Chopped glass fibers were purchased from Lingshou County Hongshang Mineral Products Co., Ltd., with a fiber length of 5 mm and an aspect ratio of 150:1;

[0137] (6) Heavy calcium carbonate: purchased from Guangxi Junhui Polymer Technology Co., Ltd.;

[0138] (7) Antioxidant MB: purchased from Shandong Shengao Chemical Technology Co., Ltd.

[0139] Example 1

[0140] An acoustic material comprising a first rubber layer, an intermediate layer, and a second rubber layer stacked in sequence; the intermediate layer comprising a polyurethane foam layer and a reinforced rubber layer stacked in sequence; the polyurethane foam layer being obtained by hot pressing polyether-type thermosetting polyurethane foam A;

[0141] The raw materials for preparing the reinforced rubber layer include: 80 parts by weight of EPDM raw rubber, 400 parts by weight of a mixed solvent (mixed by benzene and n-pentane in a mass ratio of 1:9), 60 parts by weight of fumed silica, 5 parts by weight of hydrogenated rosin resin, 30 parts by weight of chopped aramid fiber, 0.5 parts by weight of sulfur, 0.5 parts by weight of zinc stearate, 2 parts by weight of accelerator TT, 3 parts by weight of zinc oxide, and 1 part by weight of antioxidant MB;

[0142] The raw materials for preparing the first rubber layer and the second rubber layer include: 80 parts by weight of EPDM raw rubber, 400 parts by weight of a mixed solvent (mixed by benzene and n-pentane in a mass ratio of 1:9), 60 parts by weight of fumed silica, 50 parts by weight of heavy calcium carbonate, 5 parts by weight of hydrogenated rosin resin, 0.5 parts by weight of sulfur, 0.5 parts by weight of zinc stearate, 2 parts by weight of a mixing accelerator (a mixture of TMTD, MBT, TRA and TDEC in a mass ratio of 1:3:1:1), 3 parts by weight of zinc oxide, and 1 part by weight of an antioxidant MB;

[0143] The mixing method of the raw materials for preparing the reinforced rubber layer comprises the following steps:

[0144] (S1) adding the mixed solvent and EPDM rubber into a planetary mixer, setting the temperature to 50° C. and the speed to 400 rpm, and dissolving them without vacuum for 5 hours until they are completely dissolved to obtain a first solution;

[0145] (S2) adding hydrogenated rosin resin, accelerator TT, zinc oxide, zinc stearate, antioxidant MB and sulfur to the first solution in sequence and mixing for 30 minutes to obtain a second solution;

[0146] (S3) adding fumed silica and chopped aramid fibers to the second solution and mixing for 30 minutes, pouring out the resulting solution, mixing in a homogenizer at a speed of 1300 rpm for 10 minutes, turning on a vacuum pump, and degassing at the same rate for 3 minutes to obtain a raw material for preparing the reinforced rubber layer;

[0147] The mixing method of the raw materials for preparing the first rubber layer and the second rubber layer comprises the following steps:

[0148] (F1) adding the mixed solvent and EPDM rubber into a planetary mixer, setting the temperature to 50° C. and the speed to 400 r / min, and dissolving without vacuum for 5 h until completely dissolved to obtain a third solution;

[0149] (F2) adding hydrogenated rosin resin, a mixing accelerator, zinc oxide, zinc stearate, an antioxidant MB, and sulfur to the third solution in sequence and mixing for 30 minutes, then adding fumed silica and heavy calcium carbonate and mixing for 30 minutes. The resulting solution was poured out and mixed in a homogenizer at a speed of 1300 r / min for 10 minutes. The vacuum pump was turned on and deaerated at the same rate for 3 minutes to obtain raw materials for preparing the first rubber layer and the second rubber layer.

[0150] The method for preparing the acoustic material comprises the following steps:

[0151] (1) The temperature of the flat-plate hot press was raised to 200°C, and a polyether-type thermosetting polyurethane foam A with a thickness of 13 mm was placed therein. The polyurethane foam layer was formed at one time for 100 s under a pressure of 0.5 MPa to form a polyurethane foam layer with a thickness of 0.2 mm.

[0152] (2) After the polyurethane foam layer is cooled, a coating machine is used to apply the raw material for preparing the reinforced rubber layer three times on one surface of the polyurethane foam layer, and after the solvent evaporates, a reinforced rubber film with a thickness of 200 μm is formed to obtain a prefabricated intermediate layer;

[0153] (3) using a coating machine to evenly apply the raw material for the preparation of the first rubber layer and the raw material for the preparation of the second rubber layer on both surfaces of the prefabricated intermediate layer three times each, and after the solvent evaporates, a rubber film with a thickness of 200 μm is formed on both surfaces of the prefabricated intermediate layer to obtain a composite material;

[0154] (4) The dried composite material is vulcanized and molded at 190° C. and 0.35 MPa for 100 seconds to obtain the acoustic material.

[0155] Example 2

[0156] An acoustic material comprising a first rubber layer, an intermediate layer, and a second rubber layer stacked in sequence; the intermediate layer comprising a polyurethane foam layer and a reinforced rubber layer stacked in sequence; the polyurethane foam layer being obtained by hot pressing polyester thermosetting polyurethane foam;

[0157] The raw materials for preparing the reinforced rubber layer include: 90 parts by weight of NBR raw rubber, 550 parts by weight of a mixed solvent (mixed by toluene and n-hexane in a mass ratio of 2:8), 40 parts by weight of fumed silica, 10 parts by weight of 138# rosin resin, 20 parts by weight of chopped carbon fibers, 1 part by weight of sulfur, 1 part by weight of zinc stearate, 3 parts by weight of accelerator TT, 4 parts by weight of zinc oxide, and 1.5 parts by weight of antioxidant MB;

[0158] The raw materials for preparing the first rubber layer and the second rubber layer include: 90 parts by weight of EPDM raw rubber, 550 parts by weight of a mixed solvent (mixed by toluene and n-hexane in a mass ratio of 2:8), 40 parts by weight of fumed silica, 30 parts by weight of heavy calcium carbonate, 10 parts by weight of 138# rosin resin, 1 part by weight of sulfur, 1 part by weight of zinc stearate, 3 parts by weight of a mixed accelerator (a mixture of TMTD, MBT, TRA and TDEC in a mass ratio of 1.1:4:1.1:1.1), 4 parts by weight of zinc oxide, and 1.5 parts by weight of an antioxidant MB;

[0159] The mixing method of the raw materials for preparing the reinforced rubber layer comprises the following steps:

[0160] (S1) adding the mixed solvent and NBR raw rubber into a planetary mixer, setting the temperature to 60° C. and the speed to 500 r / min, and dissolving them without vacuum for 3 h until they are completely dissolved to obtain a first solution;

[0161] (S2) adding 138# rosin resin, accelerator TT, zinc oxide, zinc stearate, antioxidant MB and sulfur to the first solution in sequence and mixing for 20 minutes to obtain a second solution;

[0162] (S3) adding fumed silica and chopped carbon fibers to the second solution, mixing for 20 minutes, pouring out the stirred solution, mixing in a homogenizer at a speed of 1100 rpm for 8 minutes, turning on a vacuum pump, and degassing at the same rate for 2 minutes to obtain a raw material for preparing the reinforced rubber layer;

[0163] The mixing method of the raw materials for preparing the first rubber layer and the second rubber layer comprises the following steps:

[0164] (F1) Add the mixed solvent and EPDM rubber into a planetary mixer, set the temperature to 60° C., and the speed to 500 r / min, and dissolve without vacuum for 3 h until completely dissolved to obtain a third solution;

[0165] (F2) 138# rosin resin, a mixing accelerator, zinc oxide, zinc stearate, an antioxidant MB, and sulfur were sequentially added to the third solution and mixed for 20 minutes. Then, fumed silica and heavy calcium carbonate were added and mixed for 20 minutes. The resulting solution was poured out and mixed in a homogenizer at a speed of 1100 r / min for 8 minutes. A vacuum pump was turned on and deaerated at the same rate for 2 minutes to obtain raw materials for preparing the first rubber layer and the second rubber layer;

[0166] The method for preparing the acoustic material comprises the following steps:

[0167] (1) The temperature of the flat-plate hot press was raised to 220°C, a polyester thermosetting polyurethane foam with a thickness of 11 mm was placed therein, and the polyurethane foam layer with a thickness of 0.4 mm was formed by one-step molding at 0.4 MPa for 70 seconds.

[0168] (2) After the polyurethane foam layer is cooled, a coating machine is used to apply the raw material for preparing the reinforced rubber layer twice to one surface of the polyurethane foam layer, and after the solvent evaporates, a reinforced rubber film with a thickness of 150 μm is formed to obtain a prefabricated intermediate layer;

[0169] (3) using a coating machine to evenly apply the raw material for the preparation of the first rubber layer and the raw material for the preparation of the second rubber layer on both surfaces of the prefabricated intermediate layer twice each, and after the solvent evaporates, a rubber film with a thickness of 150 μm is formed on both surfaces of the prefabricated intermediate layer to obtain a composite material;

[0170] (4) The dried composite material is vulcanized and molded at 180° C. and 0.25 MPa for 140 seconds to obtain the acoustic material.

[0171] Example 3

[0172] An acoustic material, comprising a first rubber layer, an intermediate layer, and a second rubber layer stacked in sequence; the intermediate layer comprising a first reinforced rubber layer, a polyurethane foam layer, and a second reinforced rubber layer stacked in sequence; the polyurethane foam layer being obtained by hot pressing polyether-type thermosetting polyurethane foam B;

[0173] The raw materials for preparing the first and second reinforcing rubber layers include: 100 parts by weight of SBR raw rubber, 650 parts by weight of a mixed solvent (mixed by xylene and n-heptane in a mass ratio of 3:7), 20 parts by weight of fumed silica, 15 parts by weight of 422# rosin resin, 10 parts by weight of chopped glass fibers, 2 parts by weight of sulfur, 2 parts by weight of zinc stearate, 4 parts by weight of accelerator TT, 6 parts by weight of zinc oxide, and 2 parts by weight of antioxidant MB;

[0174] The raw materials for preparing the first rubber layer and the second rubber layer include: 100 parts by weight of EPDM raw rubber, 650 parts by weight of a mixed solvent (mixed by xylene and n-heptane in a mass ratio of 3:7), 20 parts by weight of fumed silica, 10 parts by weight of heavy calcium carbonate, 15 parts by weight of 422# rosin resin, 2 parts by weight of sulfur, 2 parts by weight of zinc stearate, 4 parts by weight of a mixed accelerator (a mixture of TMTD, MBT, TRA and TDEC in a mass ratio of 1.2:6:1.2:1.2), 6 parts by weight of zinc oxide, and 2 parts by weight of an antioxidant MB;

[0175] The mixing method of the raw materials for preparing the first reinforcement rubber layer and the second reinforcement layer comprises the following steps:

[0176] (S1) adding the mixed solvent and SBR raw rubber into a planetary mixer, setting the temperature to 70° C. and the speed to 600 r / min, and dissolving them without vacuum for 2 h until they are completely dissolved to obtain a first solution;

[0177] (S2) adding 422# rosin resin, accelerator TT, zinc oxide, zinc stearate, antioxidant MB and sulfur to the first solution in sequence and mixing for 10 minutes to obtain a second solution;

[0178] (S3) adding fumed silica and chopped glass fibers to the second solution, mixing for 10 minutes, pouring out the resulting solution, mixing in a homogenizer at a speed of 1000 rpm for 5 minutes, turning on a vacuum pump, and degassing at the same rate for 1 minute to obtain raw materials for preparing the first reinforced rubber layer and the second reinforced rubber layer;

[0179] The mixing method of the raw materials for preparing the first rubber layer and the second rubber layer comprises the following steps:

[0180] (F1) Add the mixed solvent and EPDM rubber into a planetary mixer, set the temperature to 70°C and the speed to 600 r / min, and dissolve them without vacuum for 2 h until they are completely dissolved to obtain a third solution;

[0181] (F2) adding 422# rosin resin, a mixing accelerator, zinc oxide, zinc stearate, an antioxidant MB, and sulfur to the third solution in sequence and mixing for 10 minutes, then adding fumed silica and heavy calcium carbonate and mixing for 10 minutes. The resulting solution was poured out and mixed in a homogenizer at a speed of 1000 r / min for 5 minutes. The vacuum pump was turned on and deaerated at the same rate for 1 minute to obtain raw materials for preparing the first rubber layer and the second rubber layer;

[0182] The method for preparing the acoustic material comprises the following steps:

[0183] (1) The temperature of the flat-plate hot press was raised to 230°C, and a polyether-type thermosetting polyurethane foam B with a thickness of 11 mm was placed therein. The polyurethane foam layer was then formed at 0.2 MPa for 40 seconds to form a polyurethane foam layer with a thickness of 0.6 mm.

[0184] (2) After the polyurethane foam layer is cooled, the raw material for preparing the first reinforced rubber layer is coated once on one surface of the polyurethane foam layer using a coating machine, and after the solvent evaporates, a first reinforced rubber film with a thickness of 80 μm is formed. Then, the raw material for preparing the second reinforced rubber layer is coated once on the other surface of the polyurethane foam layer, and after the solvent evaporates, a second reinforced rubber film with a thickness of 80 μm is formed to obtain a prefabricated intermediate layer;

[0185] (3) using a coating machine to evenly apply the raw material for the preparation of the first rubber layer and the raw material for the preparation of the second rubber layer on both surfaces of the prefabricated intermediate layer once each, and after the solvent evaporates, forming a rubber film with a thickness of 80 μm on both surfaces of the prefabricated intermediate layer to obtain a composite material;

[0186] (4) The dried composite material is vulcanized and molded at 160° C. and 0.15 MPa for 200 seconds to obtain the acoustic material.

[0187] Example 4

[0188] An acoustic material and a preparation method thereof, which differ from Example 1 only in that the raw materials for preparing the first rubber layer and the second rubber layer include 80 parts by weight of IIR raw rubber, 400 parts by weight of a mixed solvent (mixed by benzene and n-pentane in a mass ratio of 1:9), 60 parts by weight of fumed silica, 50 parts by weight of heavy calcium carbonate, 5 parts by weight of hydrogenated rosin resin, 0.5 parts by weight of sulfur, 0.5 parts by weight of zinc stearate, 2 parts by weight of a mixing accelerator (a mixture of TMTD and DM in a mass ratio of 1:2), 3 parts by weight of zinc oxide, and 1 part by weight of an antioxidant MB. The remaining raw materials, process parameters, and steps are the same as those in Example 1.

[0189] Comparative Example 1

[0190] An acoustic material and a preparation method thereof, the preparation method comprising:

[0191] The temperature of the flat-plate hot press was raised to 200°C, and a polyether-type thermosetting polyurethane foam A with a thickness of 13 mm was placed therein. The mold was then formed at a pressure of 0.5 MPa for 100 s to obtain an acoustic material with a thickness of 0.2 mm.

[0192] Comparative Example 2

[0193] An acoustic material and a preparation method thereof, the preparation method comprising:

[0194] (1) The temperature of the flat-plate hot press was raised to 200°C, and a polyether-type thermosetting polyurethane foam A with a thickness of 13 mm was placed therein. The polyurethane foam layer was formed at one time for 100 s under a pressure of 0.5 MPa to form a polyurethane foam layer with a thickness of 0.2 mm.

[0195] (2) After the polyurethane foam layer is cooled, the raw materials for preparing the first rubber layer and the raw materials for preparing the second rubber layer are uniformly applied to both surfaces of the polyurethane foam layer three times each using a coating machine. After the solvent evaporates, rubber films with a thickness of 200 μm are formed on both surfaces of the polyurethane foam layer to obtain a composite material. The raw materials for preparing the first rubber layer and the raw materials for preparing the second rubber layer and the mixing method are the same as those in Example 1.

[0196] (3) The dried composite material is vulcanized and molded at 190° C. and 0.35 MPa for 100 seconds to obtain the acoustic material.

[0197] Comparative Example 3

[0198] An acoustic material and a preparation method thereof, the preparation method comprising:

[0199] (1) The temperature of the flat-plate hot press was raised to 200°C, and a polyether-type thermosetting polyurethane foam A with a thickness of 13 mm was placed therein. The polyurethane foam layer was formed at one time for 100 s under a pressure of 0.5 MPa to form a polyurethane foam layer with a thickness of 0.2 mm.

[0200] (2) After the polyurethane foam layer is cooled, the raw materials for preparing the reinforced rubber layer are coated on one surface of the polyurethane foam layer three times using a coating machine. After the solvent evaporates, a reinforced rubber film with a thickness of 200 μm is formed. After drying, the film is vulcanized and molded at 190° C. and 0.35 MPa for 100 seconds to obtain the acoustic material. The raw materials for preparing the reinforced rubber layer and the mixing method are the same as those in Example 1.

[0201] Comparative Example 4

[0202] An acoustic material, comprising a first rubber layer, an intermediate layer, and a second rubber layer stacked in sequence; the intermediate layer comprises a polyurethane foam layer and a reinforced rubber layer stacked in sequence; the polyurethane foam layer is made of polyether thermoplastic polyurethane foam (M-70 purchased from Suzhou Shensai New Materials Co., Ltd., with a density of 700 kg / m 3 );

[0203] The method for preparing the acoustic material comprises the following steps:

[0204] (1) Using a coating machine, the raw materials for preparing the reinforced rubber layer are applied three times to one surface of a polyurethane foam layer having a thickness of 0.2 mm. After the solvent evaporates, a reinforced rubber film having a thickness of 200 μm is formed to obtain a prefabricated intermediate layer. The raw materials for preparing the reinforced rubber layer and the mixing method are the same as those in Example 1.

[0205] (2) Using a coating machine, the raw materials for the preparation of the first rubber layer and the raw materials for the preparation of the second rubber layer are uniformly applied to both surfaces of the prefabricated intermediate layer three times each. After the solvent evaporates, rubber films with a thickness of 200 μm are formed on both surfaces of the prefabricated intermediate layer to obtain a composite material. The raw materials for the preparation of the first rubber layer and the raw materials for the preparation of the second rubber layer and the mixing method are the same as those in Example 1.

[0206] (3) The dried composite material is vulcanized and molded at 190° C. and 0.35 MPa for 100 seconds to obtain the acoustic material.

[0207] Performance Testing

[0208] (1) Tensile strength and elongation at break: tested in accordance with GB / T 528-2009;

[0209] (2) Hydrolysis test: The samples cut into dumbbell bars were boiled in hot water at 90°C for 15 days. After cooling and drying, the tensile strength and elongation at break of the boiled samples were tested according to GB / T 528-2009. The tensile strength attenuation rate and elongation at break attenuation rate after hydrolysis were calculated according to the following formula;

[0210] Attenuation rate γ = (C0 - C1) / C0 × 100%;

[0211] Wherein, C0 is the tensile strength or elongation at break before hydrolysis; C1 is the tensile strength or elongation at break after hydrolysis;

[0212] (3) UV aging: ambient temperature 60°C, light intensity 0.89W / m 2 , UVA-340 lamp, irradiation time 72h; test the tensile strength, tensile modulus and elongation at break after UV aging, and calculate the tensile strength attenuation rate, tensile modulus attenuation rate and elongation at break attenuation rate after UV aging according to the following formula; the tensile modulus is tested with reference to GB / T 1040.1-2018 and calculated as the slope in the strain range of 0.25-1%; the tensile strength and elongation at break are tested in accordance with GB / T 528-2009;

[0213] Decay rate

[0214] Wherein, D0 is the tensile strength, elongation at break or tensile modulus before UV aging; D1 is the tensile strength, elongation at break or tensile modulus after UV aging;

[0215] (4) Density: Tested in accordance with GB / T 6343-2009;

[0216] The acoustic materials provided in Examples 1-4 and Comparative Examples 1-4 were tested according to the above method. The test results are shown in Table 1 below:

[0217] Table 1

[0218]

[0219] It can be seen from the test data in Table 1 that the acoustic material provided by the present invention has the characteristics of low density, good mechanical properties, good hydrolysis resistance and good aging resistance.

[0220] It can be seen from Example 4 that when the EPDM raw rubber in the raw materials for preparing the first rubber layer and the second rubber layer is replaced with other rubber raw rubbers, the aging resistance of the acoustic material deteriorates.

[0221] It can be seen from Comparative Example 1 that when only the hot-pressed thermosetting polyurethane foam is used as the acoustic material, the mechanical properties, hydrolysis resistance and aging resistance of the acoustic material are significantly deteriorated.

[0222] It can be seen from Comparative Example 2 that without providing the reinforcing rubber layer, the tensile strength of the acoustic material becomes significantly smaller.

[0223] It can be seen from Comparative Example 3 that without the first rubber layer and the second rubber layer, the hydrolysis resistance and aging resistance of the acoustic material deteriorate.

[0224] It can be seen from Comparative Example 4 that when thermoplastic polyurethane foam is used as the polyurethane foam layer, the foam liquefies during the vulcanization molding process, causing the cells to disappear and the low-density characteristic to be lost.

[0225] The applicant declares that the present invention uses the above-described embodiments to illustrate the acoustic material, preparation method, and application thereof. However, the present invention is not limited to the above-described embodiments, and this does not necessarily mean that the present invention must rely on the above-described embodiments for implementation. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions for the raw materials of the present invention, addition of auxiliary ingredients, and selection of specific methods, etc., fall within the scope of protection and disclosure of the present invention.

Claims

1. An acoustic material, characterized in that: The acoustic material comprises a first rubber layer, a middle layer and a second rubber layer which are stacked in sequence; The intermediate layer includes a first intermediate layer or a second intermediate layer; The first intermediate layer comprises a polyurethane foam layer and a reinforced rubber layer which are stacked; The second intermediate layer comprises a first reinforced rubber layer, a polyurethane foam layer and a second reinforced rubber layer stacked in sequence; The polyurethane foam layer is obtained by hot pressing thermosetting polyurethane foam.

2. The acoustic material according to claim 1, characterized in that The density of the acoustic material is 0.7-0.9 g / cm 3 ; Preferably, the thermosetting polyurethane foam includes polyether-type thermosetting polyurethane foam or polyester-type thermosetting polyurethane foam; Preferably, the density of the thermosetting polyurethane foam is 20-150 kg / m 3 ; Preferably, the thickness of the thermosetting polyurethane foam is 8-15 mm; Preferably, the temperature of the hot pressing is 200-230°C; Preferably, the hot pressing pressure is 0.2-0.5 MPa; Preferably, the hot pressing time is 40-100s; Preferably, the polyurethane foam layer has a thickness of 0.2-0.6 mm.

3. The acoustic material according to claim 1 or 2, characterized in that The raw materials for preparing the reinforced rubber layer, the first reinforced rubber layer and the second reinforced rubber layer independently include raw rubber, a first mixed solvent, a first special resin, fiber, a first vulcanizing agent, zinc stearate, a first accelerator and zinc oxide; Preferably, the raw materials for preparing the reinforced rubber layer, the first reinforced rubber layer and the second reinforced rubber layer independently include the following components in parts by weight:

4. The acoustic material according to claim 3, characterized in that The rubber raw rubber includes any one of EPDM rubber raw rubber, butadiene rubber raw rubber, chloroprene rubber raw rubber, nitrile rubber raw rubber, butyl rubber raw rubber, styrene-butadiene rubber raw rubber, natural rubber raw rubber or isoprene rubber raw rubber, or a combination of at least two thereof; Preferably, the first mixed solvent comprises a combination of a first aromatic solvent and a first aliphatic solvent; Preferably, the first aromatic solvent comprises any one of benzene, toluene or xylene, or a combination of at least two thereof; Preferably, the first aliphatic solvent comprises any one of n-pentane, n-hexane, cyclohexane or n-heptane, or a combination of at least two thereof; Preferably, the mass ratio of the first aromatic solvent to the first aliphatic solvent is (0.1-0.5):1; Preferably, the first specialty resin comprises any one or a combination of at least two of hydrogenated rosin resin, disproportionated rosin, polymerized rosin, maleated rosin, rosin ester, modified rosin ester or rosin-based phenolic resin; Preferably, the fiber comprises any one of polyester fiber, vinylon fiber, rayon fiber, aramid fiber, carbon fiber, glass fiber or metal fiber, or a combination of at least two thereof; Preferably, the length of the fiber is 3-5 mm; Preferably, the aspect ratio of the fiber is (100-200):1; Preferably, the first vulcanizing agent comprises sulfur; Preferably, the first accelerator comprises tetramethylthiuram disulfide; Preferably, the raw materials for preparing the reinforced rubber layer, the first reinforced rubber layer and the second reinforced rubber layer further independently include a first reinforcing agent and / or a first antioxidant; Preferably, the first reinforcing agent comprises fumed silica; Preferably, the first antioxidant comprises 2-mercaptobenzimidazole; Preferably, the first reinforcing agent in the raw materials for preparing the reinforced rubber layer, the first reinforced rubber layer and the second reinforced rubber layer is independently 20-60 parts by weight; Preferably, the first antioxidant in the raw materials for preparing the reinforced rubber layer, the first reinforced rubber layer and the second reinforced rubber layer is independently 1-2 parts by weight; Preferably, the thickness of the reinforcing rubber layer, the first reinforcing rubber layer and the second reinforcing rubber layer are each independently 80-200 μm.

5. The acoustic material according to any one of claims 1 to 4, characterized in that: The raw materials for preparing the first rubber layer and the second rubber layer independently include EPDM raw rubber, a second mixed solvent, a second special resin, a second vulcanizing agent, zinc stearate, a second accelerator and zinc oxide; Preferably, the raw materials for preparing the first rubber layer and the second rubber layer independently include the following components in parts by weight:

6. The acoustic material according to claim 5, characterized in that The second special resin includes any one or a combination of at least two of hydrogenated rosin resin, disproportionated rosin, polymerized rosin, maleated rosin, rosin ester, modified rosin ester or rosin-based phenolic resin; Preferably, the second mixed solvent comprises a combination of a second aromatic solvent and a second aliphatic solvent; Preferably, the second aromatic solvent comprises any one of benzene, toluene or xylene, or a combination of at least two thereof; Preferably, the second aliphatic solvent comprises any one of n-pentane, n-hexane, cyclohexane or n-heptane, or a combination of at least two thereof; Preferably, the mass ratio of the second aromatic solvent to the second aliphatic solvent is (0.1-0.5):1; Preferably, the second vulcanizing agent comprises sulfur; Preferably, the second accelerator comprises a combination of tetramethylthiuram disulfide, 2-mercaptobenzothiazole, dipentamethylenethiuram tetrasulfide and tellurium diethyldithiocarbamate; Preferably, the mass ratio of tetramethylthiuram disulfide, 2-mercaptobenzothiazole, dipentamethylenethiuram tetrasulfide and tellurium diethyldithiocarbamate in the second accelerator is (1-1.2):(3-6):(1-1.2):(1-1.2); Preferably, the raw materials for preparing the first rubber layer and the second rubber layer further independently include any one or a combination of at least two of a second reinforcing agent, a filling material or a second antioxidant; Preferably, the second reinforcing agent comprises fumed silica; Preferably, the filling material comprises ground calcium carbonate and / or calcined kaolin; Preferably, the second antioxidant includes 2-mercaptobenzimidazole; Preferably, the second reinforcing agent in the raw materials for preparing the first rubber layer and the second rubber layer is independently 20-60 parts by weight; Preferably, the filling material in the raw materials for preparing the first rubber layer and the second rubber layer is independently 10-50 parts by weight; Preferably, the second antioxidant in the raw materials for preparing the first rubber layer and the second rubber layer is independently 1-2 parts by weight; Preferably, the thickness of the first rubber layer and the second rubber layer are each independently 80-200 μm.

7. A method for preparing an acoustic material according to any one of claims 1 to 6, characterized in that: The preparation method comprises the following steps: (1) hot pressing the thermosetting polyurethane foam to obtain a polyurethane foam layer; (2) coating the raw materials for preparing the reinforcing rubber layer on any one surface of the polyurethane foam layer, or coating the raw materials for preparing the first reinforcing rubber layer and the raw materials for preparing the second reinforcing rubber layer on both surfaces of the polyurethane foam layer, respectively, to obtain a prefabricated intermediate layer; (3) coating the raw materials for preparing the first rubber layer and the raw materials for preparing the second rubber layer on both surfaces of the prefabricated intermediate layer, respectively, to obtain a composite material; (4) After the composite material is formed, the acoustic material is obtained.

8. The preparation method according to claim 7, characterized in that The molding temperature is 160-190°C; Preferably, the molding time is 100-200s; Preferably, the molding pressure is 0.15-0.35 MPa.

9. A folding ring, characterized in that: The material of the folding ring includes the acoustic material according to any one of claims 1 to 6.

10. A sound-generating device, characterized in that: The sound generating device comprises the folding ring as claimed in claim 9.

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