Foaming cone and preparation method and application thereof

Abstract

The invention provides a foaming cone as well as a preparation method and application thereof. The foaming cone is prepared from the following raw materials in parts by mass: 40 to 80 parts of wood pulp, 20 to 60 parts of bagasse pulp, 5 to 15 parts of carbon fibers, 3 to 15 parts of thermal expansion microspheres and 0.5 to 4 parts of sesbania powder. According to the foaming paper cone, the wood pulp, the bagasse pulp, the carbon fibers, the thermal expansion microspheres and the sesbania powder in a specific amount are combined, and the components are mutually compounded and have a synergistic effect, so that the strength of the paper cone can be effectively improved, the density is reduced, and the foaming paper cone is high in Young modulus and small in density. The foaming cone is applied to a loudspeaker, so that the loudspeaker is good in transient responsiveness, high in energy conversion efficiency and high in sensitivity, and can fully meet the performance requirements of a bass loudspeaker cone, a middle-pitch loudspeaker cone, a high-pitch loudspeaker cone and a full-frequency loudspeaker cone.

Description

Technical Field

[0001] The invention belongs to the technical field of loudspeakers, and in particular relates to a foamed paper cone and a preparation method and application thereof. Background Art

[0002] The working principle of the speaker is that when an alternating audio current is passed through the voice coil connected to the diaphragm and the centering support, the voice coil vibrates under the action of electromagnetic force in the magnetic field, thereby driving the paper cone to push the air to vibrate and produce sound. The characteristics of the paper cone directly affect the electroacoustic parameters, sound quality and service life of the speaker, and it is a key component of the vibration system.

[0003] The paper cone material should meet the following requirements: a. The density of the material should be small; b. The Young's modulus of the material should be large; c. It should have appropriate internal damping. Reducing the density of the paper cone can make the paper cone respond to audio signals faster, that is, the transient response of the speaker is good. At the same time, the energy conversion efficiency is high, which can make the speaker have higher sensitivity. The current methods for reducing the density of paper materials in the industry mainly include: ① Using "loose pressing" or "semi-loose pressing" process in the hot pressing stage; ② Using foam and porous materials to prepare composite paper materials; ③ Preparing foamed paper cones.

[0004] CN107100036A discloses a method for preparing fully loose and fully paper drum paper, comprising the following steps: disintegrating, beating, bleaching, and preparing with fillers and chemical additives to obtain drum paper pulp, slurrying the drum paper pulp, subjecting the saturated water vapor treatment after slurrying, and then extruding and dehydrating to improve the surface quality of the paper and enhance the compactness and strength of the paper; after slurrying and forming, directly vacuum drying at a medium and low temperature of 150-200°C to remove moisture from the paper. Since the paper is not subjected to high temperature and high pressure treatment during the drying process, the paper fiber is prevented from being damaged, thereby having a lower density, while enhancing the strength and flexibility of the drum paper. CN107130469A discloses a method for preparing semi-loose-pressed full-paper drum paper, the steps of which are as follows: breaking up, beating and bleaching wood raw materials to obtain wood pulp, and then mixing with fillers and chemical additives to obtain drum paper pulp, slurrying the drum paper pulp, treating it with saturated water vapor after slurrying, and then extruding and dehydrating it, and then using a low-temperature loose-pressing process in the hot pressing molding process to avoid serious damage to the pulp fibers. Although the full-pressing and semi-loose-pressing processes can reduce the density in the preparation of paper cones, the hydrogen bonding effect generated between the fibers during the drying process of such paper cones is weak, so the rigidity of the paper cones is poor, so semi-full-pressed paper cones and semi-loose-pressed paper cones are not suitable for the preparation of full-range speaker cones and high-frequency speaker cones.

[0005] CN202269006U discloses a foam paper cone with rubber edges for loudspeakers, which is composed of a rubber edge folding ring and a foam paper cone. The upper part of the foam paper cone is a rubber edge folding ring, and the lower part is a foam paper cone, which are compounded with glue. The foam paper cone is a traditional paper cone with a large amount of mica material and special reinforcing fiber added. Through the joint action of various additives and foaming agents, a loose mesh structure is formed inside the paper cone. The foam paper cone is lighter than a conventional paper cone and has lower distortion. CN113079451A discloses a foam paper cone for loudspeakers and a preparation method thereof. The raw materials for preparation include, by weight, 40-60 parts of pulp, 40-60 parts of mica, 2-10 parts of reinforcing fiber, 8-20 parts of foaming agent and 1-3 parts of sizing agent. A foam paper cone with low density is prepared by the mutual cooperation of pulp, mica, reinforcing fiber, foaming agent and sizing agent in a specific ratio, and reasonable process parameter settings.

[0006] In general, the process of foaming paper basin is simple, the product quality is stable, and the prepared paper basin has both high strength and low density. Conventional foaming paper basin is made by adding foaming agent to the pulp. During the hot pressing stage, the foaming agent is decomposed by heat to produce a large amount of gas, which makes the paper basin structure loose and reduces the density. However, most of the gas decomposed by the foaming agent will be lost from the fiber pores and the copper mesh gaps on the surface of the hot pressing mold, resulting in a large room for improvement in the comprehensive performance of the foaming paper basin.

[0007] Therefore, developing a foamed paper cone with low density, high modulus and excellent acoustic performance is an urgent problem to be solved in this field. Summary of the invention

[0008] In view of the deficiencies in the prior art, the object of the present invention is to provide a foamed paper basin and a preparation method and application thereof. Through the component design and mutual compounding of wood pulp, bagasse pulp, carbon fiber, heat-expandable microspheres and sesbania powder, the foamed paper basin has a high Young's modulus, low density and excellent acoustic performance. When applied to a speaker, the speaker has good transient responsiveness, high energy conversion efficiency and high sensitivity.

[0009] To achieve this object, the present invention adopts the following technical solutions:

[0010] In a first aspect, the present invention provides a foam paper basin, wherein the raw materials for preparing the foam paper basin include the following components in parts by mass:

[0011]

[0012] The preparation raw materials of the present invention include a combination of wood pulp, bagasse pulp, carbon fiber, heat-expandable microspheres and sesbania powder; wherein the wood pulp and bagasse pulp together construct the plant-based matrix structure of the paper basin, the carbon fiber has excellent mechanical properties, can improve the rigidity of the paper basin, and the "rebar" structure built by the carbon fiber in the matrix is ​​also conducive to reducing the density of the paper basin. The heat-expandable microspheres can expand in volume under warming conditions to achieve a foaming effect. The sesbania powder has abundant active groups in its molecular chain, which can enhance the hydrogen bonding between the paper basins, thereby improving the strength of the paper basins; at the same time, the sesbania powder produces adsorption and bridging effects between pulp fibers through the extension of long chains, thereby improving the retention rate of carbon fibers and heat-expandable microspheres in the paper basin.

[0013] In summary, the present invention provides the foamed paper basin with the characteristics of high modulus and low density through the mutual compounding and synergistic enhancement of wood pulp, bagasse pulp, carbon fiber, thermal expansion microspheres and sesbania powder. The foamed paper basin can meet the performance requirements of woofer speaker basin, midrange speaker basin, tweeter speaker basin and full-range speaker basin, so that the speaker has good transient response, high energy conversion efficiency and high sensitivity.

[0014] 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.

[0015] In the raw materials for preparing the foamed paper basin provided by the present invention, the mass proportion of the wood pulp is 40-80 parts, for example, it can be 42 parts, 45 parts, 48 ​​parts, 50 parts, 52 parts, 55 parts, 58 parts, 60 parts, 62 parts, 65 parts, 68 parts, 70 parts, 72 parts, 75 parts or 78 parts, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the said range.

[0016] The mass parts of the bagasse pulp are 20-60 parts, for example, it can be 22 parts, 25 parts, 28 parts, 30 parts, 32 parts, 35 parts, 38 parts, 40 parts, 42 parts, 45 parts, 48 ​​parts, 50 parts, 52 parts, 55 parts or 58 parts, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the said range.

[0017] The mass proportion of the carbon fiber is 5-15 parts, for example, it can be 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, 11 parts, 12 parts, 13 parts or 14 parts, as well as specific point values ​​between the above point values. 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.

[0018] The mass fraction of the heat-expandable microspheres is 3-15 parts, for example, it can be 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, 11 parts, 12 parts, 13 parts or 14 parts, as well as specific values ​​between the above points. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific points included in the range.

[0019] The mass proportion of the sesbania powder is 0.5-4 parts, for example, it can be 0.8 parts, 1 parts, 1.2 parts, 1.5 parts, 1.8 parts, 2 parts, 2.2 parts, 2.5 parts, 2.8 parts, 3 parts, 3.2 parts, 3.5 parts or 3.8 parts, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the said range.

[0020] Preferably, the wood pulp comprises bleached kraft pulp and / or unbleached kraft pulp, further preferably unbleached kraft pulp (UKP).

[0021] Preferably, the average fiber length of the unbleached kraft pulp is 1.5-2.5 mm, for example, it may be 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, 2 mm, 2.1 mm, 2.2 mm, 2.3 mm or 2.4 mm, as well as specific point values ​​between the above point values. 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.

[0022] Preferably, the average fiber length of the bagasse pulp is 0.1-1 mm, for example, it can be 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm or 0.9 mm, as well as specific point values ​​between the above point values. 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.

[0023] It should be noted that the average fiber length of the unbleached kraft pulp and the average fiber length of bagasse pulp are the average fiber lengths after pulping.

[0024] As a preferred technical solution of the present invention, unbleached sulfate wood pulp with a longer average fiber length is combined with bagasse pulp with a shorter average fiber length. The fibers of the paper basin complement each other in length, which helps the foamed paper basin to achieve the advantages of high modulus and low density.

[0025] Preferably, the average length of the carbon fiber is 4-7 mm, for example, it can be 4.2 mm, 4.5 mm, 4.8 mm, 5 mm, 5.2 mm, 5.5 mm, 5.8 mm, 6 mm, 6.2 mm, 6.5 mm or 6.8 mm, as well as specific point values ​​between the above point values. 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.

[0026] Preferably, the tensile strength of the carbon fiber is 2500-4500 MPa, for example, it may be 2800 MPa, 3000 MPa, 3500 MPa, 3500 MPa, 3800 MPa, 4000 MPa, 4200 MPa or 4400 MPa, as well as specific point values ​​between the above point values. 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.

[0027] Preferably, the elastic modulus of the carbon fiber is 200-300 GPa, for example, it may be 210 GPa, 220 GPa, 230 GPa, 240 GPa, 250 GPa, 260 GPa, 270 GPa, 280 GPa or 290 GPa, as well as specific point values ​​between the above point values. 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.

[0028] As a preferred technical solution of the present invention, the tensile strength of the carbon fiber is 3000MPa, the elastic modulus is 225GPa, and the average length is 4-7mm. It has high strength and high modulus, which can not only improve the rigidity of the foam paper basin, but also the carbon fiber can build a "rebar" structure, which is beneficial to reduce the density of the foam paper basin.

[0029] As a preferred technical solution of the present invention, the heat-expandable microspheres are polymer particles, preferably spherical particles with a core-shell structure, whose outer shell (shell) is a thermoplastic acrylate-based polymer, and the inner core includes hydrocarbons; after heating, the volume rapidly expands to 20-70 times of its own, thereby achieving a foaming effect. After the hot pressing is completed, the heat-expandable microspheres gradually cool down, and the polymer shell can still maintain a hard expanded state, and the volume is maintained at the state when heated. The shell of the heat-expandable microspheres has good elasticity and can withstand a large pressure. After heating and expansion, the heat-expandable microspheres will not break and can maintain good performance, so that the foamed paper basin made of them has low density, high modulus and excellent acoustic properties.

[0030] Preferably, the average particle size of the heat-expandable microspheres is 25-50 μm, for example, 28 μm, 30 μm, 32 μm, 35 μm, 38 μm, 40 μm, 42 μm, 45 μm or 48 μm, as well as specific point values ​​between the above point values. 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.

[0031] As a preferred technical solution of the present invention, the average particle size of the heat-expandable microspheres is ≥20 μm, more preferably 25-50 μm, and the volume of the heat-expandable microspheres expands during the hot pressing process to achieve a good foaming effect. If the average particle size of the heat-expandable microspheres is too low, the heat-expandable microspheres are easily lost with water during the preparation of the wet paper cone, that is, the number of heat-expandable microspheres remaining in the paper cone is reduced, and a good foaming effect cannot be obtained, which leads to an increase in the density of the paper cone.

[0032] Preferably, the foaming temperature of the heat-expandable microspheres is 130-225°C, for example, it can be 135°C, 140°C, 150°C, 160°C, 170°C, 180°C, 190°C, 200°C, 210°C or 220°C, as well as specific point values ​​between the above point values. 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.

[0033] The heat-expandable microspheres of the present invention can be purchased from Shanghai Waidian International Trading Co., Ltd., and the models include any one of 120DU25, 180DU25, 180DU35, 180DU45, 180DU50, 200DU35, 220DU30, and 220DU35, or a combination of at least two thereof.

[0034] Preferably, the average particle size of the sesbania powder is 10-120 μm, for example, it can be 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm or 110 μm, as well as specific point values ​​between the above point values. 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.

[0035] Preferably, the average molecular weight of the sesbania powder is 150,000-300,000, for example, it can be 160,000, 170,000, 180,000, 190,000, 200,000, 210,000, 220,000, 230,000, 240,000, 250,000, 260,000, 270,000, 280,000 or 290,000, as well as specific point values ​​between the above point values. 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.

[0036] As the preferred technical solution of the present invention, the main molecular chain of the sesbania powder is mannose connected by β-1,4 glycosidic bonds, and contains galactose side chains connected by α-1,6 glycosidic bonds, and the ratio of mannose to galactose is 2:1, and the average molecular weight is about 230,000. The present invention introduces a specific amount of sesbania powder. On the one hand, it can effectively enhance the hydrogen bonding between the foamed paper basins by utilizing the abundant active groups in its molecular chain, thereby improving the strength of the paper basins; on the other hand, the sesbania powder has a high molecular weight, and can produce adsorption and bridging effects between pulp fibers through the extension of long chains, thereby improving the retention rate of carbon fibers and thermal expansion microspheres in the foamed paper basins, so that the foamed paper basins have low density, high modulus and excellent acoustic properties.

[0037] Preferably, the density of the foaming paper basin is ≤0.55g / cm 3 , for example, it can be 0.33 g / cm 3 , 0.34g / cm 3 , 0.35g / cm 3 , 0.36g / cm 3 , 0.38g / cm 3 , 0.4g / cm 3 , 0.42g / cm 3 , 0.44g / cm 3 , 0.45g / cm 3 , 0.46g / cm 3 , 0.48g / cm 3 , 0.5g / cm 3 , 0.52g / cm 3 or 0.54g / cm 3 , and specific point values ​​between the above point values. 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, preferably ≤0.52g / cm 3 , further preferably 0.35-0.52 g / cm 3 .

[0038] Preferably, the Young's modulus of the foamed paper basin is ≥3 GPa, for example, it may be 3.2 GPa, 3.5 GPa, 3.8 GPa, 4 GPa, 4.2 GPa, 4.5 GPa, 4.8 GPa, 5 GPa, 5.2 GPa or 5.5 GPa, as well as specific point values ​​between the above point values. 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, preferably ≥3.5 GPa, and further preferably 3.5-5.2 GPa.

[0039] In a second aspect, the present invention provides a method for preparing the foamed paper basin as described in the first aspect, the preparation method comprising the following steps:

[0040] Mixing wood pulp and bagasse pulp to obtain component A;

[0041] Mix sesbania powder and water evenly to obtain component B;

[0042] The component A, the component B, the carbon fiber and the heat-expandable microspheres are uniformly mixed to obtain the component C;

[0043] The component C is made into a paper cone wet blank by a mold, and then dried and hot-pressed to obtain a paper cone blank;

[0044] The paper cone blank is punched to obtain the foamed paper cone.

[0045] In the preparation method of the foamed paper basin provided by the present invention, component C is first obtained through the steps of beating, mixing, dispersing, etc., and then a wet paper basin blank is formed through a mold; the wet paper basin blank is dried to obtain a dry paper basin blank, and then hot pressed, so that the volume of the heat-expandable microspheres rapidly expands to several dozen times of its own during the hot pressing process, thereby achieving a foaming effect. The present invention can adjust the modulus and density of the paper basin by preparing raw materials, designing the preparation process and compounding each other, so that the obtained foamed paper basin achieves excellent comprehensive effects in terms of low density, high modulus and acoustic properties. The preparation method of the foamed paper basin can be applicable to the performance requirements of woofer paper basins, midrange speaker paper basins, tweeter paper basins and full-range speaker paper basins.

[0046] Preferably, the beating is performed using a Valley beater.

[0047] Preferably, the wood pulp, bagasse pulp and water are mixed and then beaten to obtain component A.

[0048] Preferably, the beating degree of component A is 18-25°SR, for example, it can be 19°SR, 20°SR, 21°SR, 22°SR, 23°SR or 24°SR, as well as specific point values ​​between the above point values. 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.

[0049] Preferably, the mass ratio of sesbania powder to water in component B is 1:(20-100), for example, it can be 1:25, 1:30, 1:35, 1:40, 1:45, 1:50, 1:55, 1:60, 1:65, 1:70, 1:75, 1:80, 1:85, 1:90 or 1:95, etc.

[0050] Preferably, the sesbania powder is mixed with water and stirred by a stirring device until completely dissolved to obtain component B.

[0051] Preferably, the component A, component B, carbon fiber and heat-expandable microspheres are mixed and diluted with water to obtain component C.

[0052] Preferably, the component C is filtered through a paper cone water filter mold to obtain a paper cone wet blank.

[0053] Preferably, the drying temperature is 60-100°C, for example, it can be 62°C, 65°C, 68°C, 70°C, 72°C, 75°C, 78°C, 80°C, 82°C, 85°C, 88°C, 90°C, 92°C, 95°C or 98°C, as well as specific point values ​​between the above point values. 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.

[0054] Preferably, the drying time is 90-120 min, for example, it can be 95 min, 100 min, 105 min, 110 min or 115 min, as well as specific point values ​​between the above point values. 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.

[0055] Preferably, the drying is carried out in a forced air drying oven.

[0056] Preferably, the hot pressing mold used for the hot pressing does not need to be provided with a copper mesh on the mold surface, nor does it need to be provided with exhaust holes on the mold.

[0057] As a preferred technical solution of the present invention, the wet paper basin blank is first dried to obtain a dry paper basin blank; the dry paper basin blank is hot pressed in a hot pressing mold (no copper mesh is required on the mold surface, and no exhaust holes are required on the mold) to obtain a paper basin blank. The wet paper basin blank cannot be directly placed in the hot pressing mold for hot pressing. The reason is that when the wet paper basin blank is hot pressed, a copper mesh needs to be set on the surface of the hot pressing mold to discharge a large amount of water vapor generated by the wet paper basin blank during hot pressing. Moreover, when the wet paper basin blank is directly hot pressed, the water evaporates rapidly, which will make the actual temperature of the hot pressing mold much lower than the set temperature, and it is impossible to ensure that the heat-expandable microspheres have the expected foaming effect.

[0058] Preferably, the temperature of the hot pressing is 130-225°C, for example, it can be 135°C, 140°C, 150°C, 160°C, 170°C, 180°C, 190°C, 200°C, 210°C or 220°C, as well as specific point values ​​between the above point values. 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.

[0059] Preferably, the hot pressing time is 30-80s, for example, it can be 35s, 40s, 45s, 50s, 55s, 60s, 65s, 70s or 75s, as well as specific point values ​​between the above point values. 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, and 40-60s is further preferred.

[0060] As a preferred technical solution of the present invention, the preparation method comprises the following steps:

[0061] Mixing wood pulp and bagasse pulp to obtain component A with a beating degree of 18-25°SR;

[0062] Mix sesbania powder and water in a mass ratio of 1:(20-100) to obtain component B;

[0063] The component A, the component B, the carbon fiber and the heat-expandable microspheres are mixed, diluted with water, and dispersed evenly to obtain the component C;

[0064] Filtering component C through a paper basin water filter mold to obtain a paper basin wet blank;

[0065] Drying the wet paper basin blank at 60-100° C. for 90-120 min to obtain a dry paper basin blank;

[0066] Placing the paper cone dry blank in a hot pressing mold, and hot pressing at 130-225° C. to obtain a paper cone blank;

[0067] The paper cone blank is punched out by using a punching die to remove the central hole and the edge material, so as to obtain the foamed paper cone.

[0068] In a third aspect, the present invention provides a speaker, comprising the foam paper cone as described in the first aspect.

[0069] Preferably, the speaker comprises a woofer, a mid-range speaker, a tweeter or a full-range speaker.

[0070] The foamed paper cone provided by the present invention has low density, high modulus and excellent acoustic performance. When the foamed paper cone is applied to a loudspeaker, the loudspeaker has good transient responsiveness, high energy conversion efficiency and high sensitivity.

[0071] Compared with the prior art, the present invention has the following beneficial effects:

[0072] (1) In the foamed paper basin provided by the present invention, by combining a specific amount of wood pulp, bagasse pulp, carbon fiber, heat-expandable microspheres and sesbania powder, the components are compounded with each other, synergistically enhanced, and work together with the preparation method, the strength of the paper basin can be effectively improved, the density can be reduced, and the Young's modulus of the foamed paper basin can be high and the density can be low. The foamed paper basin is applied to a speaker, so that the speaker has good transient responsiveness, high energy conversion efficiency, and high sensitivity, and can fully meet the performance requirements of a woofer speaker basin, a midrange speaker basin, a tweeter speaker basin and a full-range speaker basin.

[0073] (2) The density of the foamed paper basin is 0.35-0.52 g / cm by designing and compounding the components and optimizing the preparation process. 3, Young's modulus is 3.5-5.2GPa, and it has low density, high Young's modulus and excellent acoustic properties. DETAILED DESCRIPTION

[0074] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0075] As used herein, the terms "comprises," "including," "having," "containing," or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a composition, process, method, article, or apparatus that comprises the listed elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such composition, process, method, article, or apparatus.

[0076] In the following specific implementation of the present invention, the specific information of the materials used is as follows:

[0077]

[0078] The foamed paper basin and the preparation method thereof of the present invention will be described in detail below by taking a plurality of embodiments as examples, but the foamed paper basin and the preparation method thereof of the present invention are not limited to these embodiments.

[0079] Example 1

[0080] A foam paper basin and a preparation method thereof, wherein the raw materials for preparing the foam paper basin include the following components in parts by mass:

[0081]

[0082] The preparation method of the foamed paper basin specifically comprises the following steps:

[0083] (1) Dispersing UKP and bagasse pulp in water according to the above formula, and beating with a Valley beater to obtain component A with a beating degree of 22° SR;

[0084] (2) mixing sesbania powder and water at a mass ratio of 1:50, and stirring with a stirrer until completely dissolved to obtain component B;

[0085] (3) mixing the component A, the component B, the carbon fiber and the heat-expandable microspheres uniformly, and diluting with water to obtain the component C;

[0086] (4) filtering the component C through a paper basin water filter mold to obtain a paper basin wet blank;

[0087] (5) placing the wet paper cone blank in a forced air drying oven at 80° C. and drying for 100 min to obtain a dry paper cone blank;

[0088] (6) placing the paper cone dry blank in a hot pressing mold and hot pressing at 210° C. for 45 seconds to obtain a paper cone blank;

[0089] (7) Placing the paper cone blank in a punching die, removing the holes and edge materials in the paper cone, and obtaining the foamed paper cone.

[0090] Examples 2-10, Comparative Examples 1-6

[0091] A foamed paper cone, which differs from Example 1 only in that the components and / or the hot pressing temperature are different, as shown in Table 1, wherein "--" represents that the component is not added; the preparation method of the paper cone is the same as that of Example 1.

[0092] Table 1

[0093]

[0094] Comparative Example 7

[0095] A foam paper basin, the raw materials for its preparation are the same as those in Example 1, and the difference between it and Example 1 is that the preparation is different, as follows:

[0096] (1)-(4) are the same as in Example 1 to obtain a wet paper cone blank;

[0097] (5) placing the wet paper basin blank in a hot pressing mold and hot pressing at 210° C. for 45 seconds to obtain a paper basin blank;

[0098] (6) placing the paper cone blank in a punching die, removing the holes and edge materials in the paper cone, and obtaining the foamed paper cone.

[0099] Comparative Example 8

[0100] A foam paper basin, the raw materials for its preparation are the same as those in Example 1, and the difference between it and Example 1 is that the preparation is different, as follows:

[0101] (1)-(4) are the same as in Example 1 to obtain a wet paper cone blank;

[0102] (5) placing the wet paper cone blank in a 210° C. forced air drying oven and drying for 30 min to obtain a paper cone blank;

[0103] (6) placing the paper cone blank in a punching die, removing the holes and edge materials in the paper cone, and obtaining the foamed paper cone.

[0104] Comparative Example 9

[0105] A foaming paper basin, which is different from Example 1 only in that the combination of UKP and bagasse pulp is replaced by 100 parts of bamboo pulp, and other components, amounts and preparation methods are the same as those in Example 1.

[0106] Comparative Example 10

[0107] A foaming paper basin, which differs from Example 1 only in that the heat-expandable microspheres are replaced by azodicarbonamide of an equal mass as a foaming agent, and other components, amounts and preparation methods are the same as those in Example 1.

[0108] The performance test of the foamed paper basin provided in Examples 1-10 and Comparative Examples 1-10 was carried out as follows:

[0109] (1) Density: Using the mass / volume method, the mass of the foam paper basin is measured by an electronic balance, the thickness of the foam paper basin is measured by a micrometer, and the volume of the foam paper basin is calculated using its 3D model;

[0110] (2) Young's modulus: The material parameter test module (MPM) in KLIPPEL R&D SYSTEM is used to test the Young's modulus of the paper cone to characterize its strength;

[0111] (3) Characteristic sensitivity of loudspeaker: The foam paper cone to be tested is used to assemble a subwoofer. The outer diameter of the loudspeaker is 133 mm, the height is 72 mm, the rated power is 30 W, and the maximum power is 40 W. A pink noise signal within the rated frequency range is applied to the loudspeaker. When the voltage is equivalent to the dissipation of 1 watt of electrical power at the rated impedance, the sound pressure generated at a distance of 1 meter from the reference point on the reference axis is expressed in decibels (dB).

[0112] The test results are shown in Table 2.

[0113] Table 2

[0114]

[0115]

[0116] It can be seen from the test data in Table 2 that the present invention combines wood pulp, bagasse pulp, carbon fiber, heat-expandable microspheres and sesbania powder in specific amounts, and the components are compounded and synergistically enhanced, and work together with a specific preparation method to make the foamed paper basin have a high Young's modulus and a low density. The foamed paper basins provided in Examples 1-7 have a Young's modulus of 3.5-5.2 GPa and a density of 0.35-0.52 g / cm 3 When the foamed paper cone is applied to a loudspeaker, the loudspeaker has good transient response, high energy conversion efficiency, and high sensitivity, and its characteristic sensitivity is 88-91dB.

[0117] The present invention makes the retention rate of heat-expandable microspheres in the paper basin high through the particle size design of heat-expandable microspheres, the optimization of the hot pressing process and their joint action, and the volume expands rapidly during the hot pressing process, achieving excellent foaming effect, and giving the foamed paper basin the characteristics of low density and high modulus. Comparing Example 1 and Example 8, it can be seen that when the particle size of the heat-expandable microspheres in the raw material is small, in the filtering step of preparing the wet blank of the paper basin, most of the heat-expandable microspheres will be lost with water, and the number of heat-expandable microspheres retained in the paper basin will be greatly reduced, and the foaming effect of the paper basin is not good, so the density of the paper basin tends to increase. From the comparison of Example 1 and Examples 9-10, it can be seen that the temperature of hot pressing should be within a reasonable range. When the hot pressing temperature is too low, the heat-expandable microspheres do not reach the initial expansion temperature and it is difficult to achieve foaming; when the hot pressing temperature is too high, the shell of the heat-expandable microspheres breaks and cannot maintain a hollow shape. Therefore, if the hot pressing temperature is too low or too high, the density of the paper basin will increase, and the sensitivity of the speaker using it will decrease.

[0118] In the foaming paper basin provided by the present invention, wood pulp, bagasse pulp, carbon fiber, heat-expandable microspheres and sesbania powder are compounded in a specific amount, and wood pulp and bagasse pulp jointly construct a plant-based matrix structure, and carbon fiber can not only improve the rigidity of the paper basin, but also the "rebar" structure built by the carbon fiber in the matrix is ​​also conducive to reducing the density of the paper basin; the sesbania powder can enhance the hydrogen bonding between the paper basins and further improve the strength of the paper basins, and can also produce adsorption and bridging effects between the pulp fibers through the extension of long chains, thereby improving the retention rate of carbon fiber and heat-expandable microspheres in the paper basin. The synergistic effect of each raw material component and the specific preparation method are compounded to make the foaming paper basin have high strength and Young's modulus and low density, thereby improving the sensitivity of the speaker.

[0119] From the comparison between Example 1 and Comparative Example 1, it can be seen that when the amount of carbon fiber added is reduced, the Young's modulus of the paper basin is reduced. At the same time, a small amount of carbon fiber cannot build a "rebar" structure, so the density of the foamed paper basin is also increased. Although carbon fiber has a high elastic modulus and a high tensile modulus, its surface is smooth and has no active functional groups, so hydrogen bonding cannot be formed between carbon fiber and plant fiber. From the comparison between Example 1 and Comparative Example 2, it can be seen that when the amount of carbon fiber added is too much, the bonding force between the paper basin fibers is weakened, resulting in a decrease in the Young's modulus of the foamed paper basin.

[0120] By comparing Example 1 with Comparative Examples 3-4, it can be seen that when the proportion of heat-expandable microspheres is too low, the foaming effect of the paper basin is poor, and the density of the foamed paper basin is relatively large; when the proportion of heat-expandable microspheres is too high, although the foamed paper basin has a lower density, the Young's modulus is also greatly reduced, which is difficult to meet application requirements.

[0121] By comparing Example 1 with Comparative Examples 5-6, it can be seen that the amount of sesbania powder should be within the reasonable range specified by the present invention. When the amount of sesbania powder is too small, the strength of the foamed paper basin decreases, and the retention rate of heat-expandable microspheres and carbon fibers will also be affected, resulting in an increase in the density of the paper basin. When the amount of sesbania powder is too large, it is difficult to filter water in the filtration step of preparing the wet paper basin, the moisture content of the obtained wet paper basin increases, and the structure of the dry paper basin after drying is loose, which indirectly leads to a decrease in the Young's modulus of the obtained foamed paper basin.

[0122] Comparing Example 1 with Comparative Examples 7-8, it can be seen that in the preparation method of the foamed paper basin of the present invention, a specific preparation process must be followed, that is, the wet paper basin needs to be dried and hot pressed in sequence to obtain a high modulus, low density foamed paper basin. If the wet paper basin is directly hot pressed, the foaming effect of the heat-expandable microspheres will be poor, resulting in an increase in the density of the paper basin; if the wet paper basin is directly dried in a high-temperature blast drying oven, the hydrogen bonding effect formed between the paper basin fibers will be weakened, the paper basin structure will be loose, and the Young's modulus of the paper basin will be reduced.

[0123] Comparing Example 1 with Comparative Example 9, it can be seen that the raw materials of the foamed paper basin of the present invention use UKP with a longer average fiber length (the average fiber length after pulping is 1.9 mm) and bagasse pulp with a shorter average fiber length (the average fiber length after pulping is 0.5 mm), and the fibers of the paper basin complement each other in length, which helps the foamed paper basin to achieve the advantages of high modulus and low density. The bamboo pulp of Comparative Example 9 has an average fiber length of 1.1 mm after pulping, and its matrix structure as a plant-based matrix will cause the density of the foamed paper basin to increase and the modulus to decrease.

[0124] By comparing Example 1 with Comparative Example 10, it can be seen that the average particle size of the conventional azodicarbonamide foaming agent is only 6-12 μm. When the paper cone is wet-formed, the conventional foaming agent will be lost during the water filtration process, resulting in a decrease in its retention rate in the paper cone and a decrease in the foaming effect, which in turn leads to an increase in the density of the foamed paper cone and a decrease in the characteristic sensitivity of the speaker.

[0125] The applicant declares that the present invention uses the above-mentioned embodiments to illustrate the foaming paper basin and its preparation method and application, but the present invention is not limited to the above-mentioned embodiments, that is, it does not mean that the present invention must rely on the above-mentioned embodiments to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of the raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A foaming paper basin, characterized in that: The raw materials for preparing the foaming paper basin include the following components in parts by mass:

2. The foaming paper basin according to claim 1, characterized in that: The wood pulp comprises bleached kraft wood pulp and / or unbleached kraft wood pulp, preferably unbleached kraft wood pulp; Preferably, the average fiber length of the unbleached kraft pulp is 1.5-2.5 mm; Preferably, the average fiber length of the bagasse pulp is 0.1-1 mm; Preferably, the average length of the carbon fibers is 4-7 mm.

3. The foaming paper basin according to claim 1 or 2, characterized in that: The average particle size of the heat-expandable microspheres is 25-50 μm; Preferably, the foaming temperature of the heat-expandable microspheres is 130-225°C.

4. The foaming paper basin according to any one of claims 1 to 3, characterized in that: The average particle size of the sesbania powder is 10-120 μm; Preferably, the average molecular weight of the sesbania powder is 150,000-300,000.

5. The foaming paper basin according to any one of claims 1 to 4, characterized in that: The density of the foamed paper basin is ≤0.55g / cm 3 , preferably 0.35-0.52g / cm 3 ; Preferably, the Young's modulus of the foamed paper basin is ≥3 GPa, more preferably 3.5-5.2 GPa.

6. A method for preparing a foamed paper basin according to any one of claims 1 to 5, characterized in that: The preparation method comprises the following steps: Mixing wood pulp and bagasse pulp to obtain component A; Mix sesbania powder and water evenly to obtain component B; The component A, the component B, the carbon fiber and the heat-expandable microspheres are uniformly mixed to obtain the component C; The component C is made into a paper cone wet blank by a mold, and then dried and hot-pressed to obtain a paper cone blank; The paper cone blank is punched to obtain the foamed paper cone.

7. The preparation method according to claim 6, characterized in that: The beating degree of component A is 18-25°SR; Preferably, the mass ratio of sesbania powder to water in component B is 1:(20-100).

8. The preparation method according to claim 6 or 7, characterized in that: The component C is filtered through a paper basin water filter mold to obtain a paper basin wet blank; Preferably, the drying temperature is 60-100°C; Preferably, the drying time is 90-120 min; Preferably, the temperature of the hot pressing is 130-225°C.

9. The preparation method according to any one of claims 6 to 8, characterized in that: The preparation method comprises the following steps: Mixing wood pulp and bagasse pulp to obtain component A with a beating degree of 18-25°SR; Mix sesbania powder and water in a mass ratio of 1:(20-100) to obtain component B; The component A, the component B, the carbon fiber and the heat-expandable microspheres are mixed and diluted with water to be evenly dispersed to obtain the component C; Filtering component C through a paper basin water filter mold to obtain a paper basin wet blank; Drying the wet paper basin blank at 60-100° C. for 90-120 min to obtain a dry paper basin blank; Placing the paper cone dry blank in a hot pressing mold, and hot pressing at 130-225° C. to obtain a paper cone blank; The paper cone blank is punched out by using a punching die to remove the central hole and the edge material, so as to obtain the foamed paper cone.

10. A loudspeaker, characterized in that: The speaker comprises the foam paper cone as described in any one of claims 1-5.

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