Modified poplar fiber and preparation method and application thereof

Abstract

The invention relates to a modified poplar fiber as well as a preparation method and application thereof. The preparation method comprises the following steps: performing primary pulping on poplar wool to obtain dissociated poplar fiber, adding pulping enzyme for secondary pulping to obtain fibrillated poplar fiber, screening pulp, and treating with hydrophobic treatment liquid to obtain the modified poplar fiber, the modified poplar fiber provided by the invention has the characteristics of uniform size and good hydrophobicity, is used for the modified poplar fiber in the preparation of the loudspeaker cone, can be tightly combined with paper pulp fiber, reduces moisture absorption, can simultaneously improve the temperature resistance, waterproof and moistureproof effects and Young modulus of the loudspeaker cone, and increases the damping performance.

Description

Technical Field

[0001] The present invention relates to the technical field of loudspeaker manufacturing technology, and in particular to a modified poplar fiber and a preparation method and application thereof. Background Art

[0002] As the core vibration element of the electroacoustic conversion system, the speaker cone's performance directly determines key acoustic indicators such as the speaker's frequency response range, sound pressure level, and harmonic distortion. Traditional speaker cones are primarily formed from plant fibers through a wet process. However, these factors, such as insufficient rigidity, poor dimensional stability, and weak high-frequency response, hinder the development of high-end audio equipment.

[0003] In recent years, in order to improve the performance of paper cones, some researchers have added sawdust fibers to the paper cone materials to improve the sound quality. The fibers inside the speaker cone containing sawdust are interwoven with each other, which can quickly absorb the energy in the transmission process, smooth the frequency response curve, reduce split resonance, achieve healthy sound integration, reduce sound distortion, and the sound characteristics of the speaker cone produced are smooth and natural. However, due to its material characteristics, the sawdust material is sensitive to temperature and humidity. Changes in the use environment may affect the sound, and multiple vibrations may cause irreversible deformation. To this end, the existing technology usually requires impregnation or spraying surface treatment in the last stage of the paper cone forming process to ensure strength and resistance to environmental changes. In addition, due to the addition of irregular sawdust materials, the speaker cone containing sawdust is difficult to form a dense three-dimensional network during the wet papermaking process, and it is difficult to meet the high modulus requirements. At the same time, the sawdust particle size distribution is uneven, which can easily cause mold damage during the paper cone preparation process, making molding more difficult and having poor consistency.

[0004] Therefore, there is an urgent need to develop a material that can improve the temperature and humidity resistance of the speaker cone and maintain a higher Young's modulus of the speaker cone. Summary of the Invention

[0005] In order to solve the above technical problems, the present invention provides a modified poplar fiber and its preparation method and application. The modified poplar fiber has the characteristics of uniform size and good hydrophobicity. When the modified poplar fiber is used in the preparation of speaker paper cones, it can be tightly combined with pulp fibers to reduce moisture absorption. It can also improve the temperature resistance, waterproof and moisture-proof effect and Young's modulus of the speaker paper cone and increase the damping performance.

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

[0007] In a first aspect, the present invention provides a method for preparing modified poplar fiber, the preparation method comprising the following steps: beating poplar wood fibers once to obtain dissociated poplar fibers, adding a beating enzyme for secondary beating to obtain split poplar fibers, screening the pulp, and treating with a hydrophobic treatment liquid to obtain the modified poplar fibers.

[0008] In the present invention, the first beating causes the fibers in the poplar wood fibers to be initially dissociated, and the second beating promotes the fiber splitting and brooming; the pulp screening can remove oversized fibers. By first dissociating the poplar wood fibers and then splitting them, the poplar fibers fully maintain their wood structure while the fiber surfaces are fully split and broomed, providing a good site for subsequent hydrophobic treatment liquid treatment, and also providing a good site for the modified poplar fibers to be combined with pulp fibers when used to prepare speaker cones; the poplar fibers of uniform and appropriate size are screened out by pulp screening. The prepared modified poplar fibers have uniform size and can avoid problems such as uneven fiber distribution and poor consistency. Using the modified poplar fibers in the preparation of speaker cones can simultaneously improve the waterproof and moisture-proof effect and Young's modulus of the speaker cones. The modified poplar fibers are tightly combined with the pulp fibers, and the prepared speaker cones have pure and natural sound quality, smoother high-frequency response, and can significantly reduce distortion.

[0009] Preferably, the length of the poplar wood fibers is 1 to 2 cm, for example, 1.1 cm, 1.2 cm, 1.3 cm, 1.4 cm, 1.5 cm, 1.6 cm, 1.7 cm, 1.8 cm or 1.9 cm.

[0010] Preferably, the one-time beating is light knife beating, the beating time is 1 to 2 hours, for example 1.1h, 1.2h, 1.3h, 1.4h, 1.5h, 1.6h, 1.7h, 1.8h or 1.9h, etc., the beating concentration is 2% to 5% (for example 2.3%, 2.6%, 2.9%, 3.2%, 3.5%, 3.8%, 4.1%, 4.4% or 4.7%, etc.), and the solvent is water.

[0011] In the present invention, the beating concentration refers to the solid content of the slurry during beating.

[0012] In the present invention, the light knife beating means that the distance between the bottom knife of the beater and the flying knife roller is 0.5-1 mm during beating.

[0013] In the present invention, a relatively low beating concentration is used in one beating to avoid excessive fiber dissociation. Light knife beating can allow the fibers to gradually separate under the action of mechanical force while maintaining the integrity of the fibers.

[0014] Preferably, the secondary beating is light knife beating, the beating time is 0.5 to 1 h (for example, 0.55 h, 0.6 h, 0.65 h, 0.7 h, 0.75 h, 0.8 h, 0.85 h, 0.9 h or 0.95 h, etc.), the beating concentration is 8% to 15% (for example, 9%, 10%, 11%, 12%, 13% or 14%, etc.), and the solvent is water.

[0015] Preferably, the secondary beating further includes a water washing step.

[0016] Preferably, the beating enzyme is a complex enzyme preparation.

[0017] Preferably, the complex enzyme preparation comprises cellulase and hemicellulase.

[0018] Illustratively, the complex enzyme preparation includes the TF-EB beating enzyme product of Zhejiang Chuanhua Huayang Chemical Co., Ltd.

[0019] Preferably, the amount of the beating enzyme used is 50-100 g / ton (e.g., 55 g / ton, 60 g / ton, 65 g / ton, 70 g / ton, 75 g / ton, 80 g / ton, 85 g / ton, 90 g / ton or 95 g / ton, etc.) of dissociated poplar fiber.

[0020] In the present invention, the secondary beating is carried out at a higher beating concentration, and beating enzyme is added, which promotes the fiber splitting and brooming, and avoids excessive fiber cutting while maintaining the fiber length.

[0021] Preferably, the pulp screening is performed using a flat plate vibrating screen.

[0022] Preferably, the screen gap of the flat vibrating screen is 0.2-0.3 mm, for example, 0.25 mm.

[0023] In the present invention, the pulp is screened using a flat vibrating screen, and the fibers under the screen plate of the flat vibrating screen are retained after screening. The flat vibrating screen can be used to screen out poplar fibers of uniform and appropriate size, which can maintain good consistency and product stability when added for use, and will not damage the mold when preparing the speaker paper cone, and can be well combined with the pulp fibers.

[0024] Preferably, the process further includes a drying step after the pulp screening.

[0025] Preferably, the drying temperature is 50-80°C, such as 55°C, 60°C, 65°C, 70°C or 75°C.

[0026] Preferably, the treatment with a hydrophobic treatment liquid is an immersion ultrasonic treatment with a hydrophobic treatment liquid.

[0027] Preferably, the immersion ultrasonic treatment time is 15 to 30 minutes, for example, 17 minutes, 19 minutes, 21 minutes, 23 minutes, 25 minutes, 27 minutes or 29 minutes.

[0028] Preferably, the hydrophobic treatment fluid comprises lignin and water.

[0029] Preferably, the mass percentage of lignin in the hydrophobic treatment liquid is 0.5% to 2%, for example, 0.7%, 0.9%, 1.1%, 1.3%, 1.5%, 1.7% or 1.9%.

[0030] Preferably, the hydrophobic treatment liquid further comprises nanocellulose.

[0031] Preferably, the mass percentage of nanocellulose in the hydrophobic treatment liquid is 0.25% to 1%, for example, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8% or 0.9%.

[0032] Preferably, the average diameter of the nanocellulose is 10 to 30 nm, for example, 12 nm, 14 nm, 16 nm, 18 nm, 20 nm, 22 nm, 24 nm, 26 nm or 28 nm.

[0033] Preferably, the average length of the nanocellulose is 200-400 nm, for example, 220 nm, 240 nm, 260 nm, 280 nm, 300 nm, 320 nm, 340 nm, 360 nm or 380 nm.

[0034] Preferably, the lignin comprises lignin sulfonate.

[0035] Preferably, the lignin sulfonate comprises sodium lignin sulfonate and / or calcium lignin sulfonate.

[0036] In the present invention, the nanocellulose is small in scale and can effectively adhere to, deposit on, or partially embed into the surface and microporous structure of the poplar fiber under the action of ultrasound, forming a micron-nano composite rough structure. Lignin can better infiltrate, adsorb, and coat the surface of the poplar fiber under the action of ultrasound, forming a thin layer rich in hydrophobic groups. The lignin in the modified poplar fiber reduces the surface energy, while the nanocellulose provides a micro-nano rough structure. The combination of the two, through dual action, can achieve a better hydrophobic effect than using either one alone. Lignin can also act as a "binder" between the nanocellulose and the poplar fiber body. The hydrophobicity and nano effect of lignin enhance waterproofness and bonding strength.

[0037] Preferably, the treatment with the hydrophobic treatment liquid further includes filtering and drying steps.

[0038] In a second aspect, the present invention provides a modified poplar fiber, which is prepared by the preparation method described in the first aspect.

[0039] Preferably, the length of the modified poplar fiber is 0.3-5 mm, for example, 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm or 4.5 mm.

[0040] Preferably, the diameter of the modified poplar fiber is 0.03-0.2 mm, for example, 0.05 mm, 0.07 mm, 0.09 mm, 0.11 mm, 0.13 mm, 0.15 mm, 0.17 mm or 0.19 mm.

[0041] In a third aspect, the present invention provides a method for preparing a speaker paper cone, comprising the steps of: first mixing pulp fiber and a cationic waterproofing agent, and then second mixing with the modified poplar fiber as described in the second aspect to obtain the speaker paper cone.

[0042] In the present invention, the preparation method first mixes pulp fiber and cationic waterproofing agent, which helps to coat the cationic waterproofing agent on the fiber surface to form a cationic film layer, and then adds modified poplar fiber. The poplar fiber in the modified poplar fiber and the nanocellulose rich on its surface have a negative charge on the surface, which can quickly adsorb and bind with the cationic film layer, thereby increasing the bonding between the poplar fiber and the pulp fiber. The nanocellulose in the modified poplar fiber can also be embedded in the gaps between the pulp fibers, thereby improving the bonding strength through physical entanglement and reducing interface defects. In addition, the cationic waterproofing agent further wraps the poplar fiber. Under high temperature and hot pressure, the cationic waterproofing agent solidifies to form a waterproof protective layer, further increasing the waterproof and moisture-proof properties of the modified poplar fiber and the speaker cone, increasing the service life of the product and broadening its usage scenarios.

[0043] Preferably, the pulp fiber includes any one of wood pulp, hemp pulp or straw pulp, or a combination of at least two of them.

[0044] Preferably, the mass ratio of wood pulp, hemp pulp and straw pulp in the pulp fiber is (5-7): (2-4): (1-2), for example, the mass ratio of wood pulp, hemp pulp and straw pulp is 5:3:1, 5:4:1, 6:3:1, 7:3:1, 6:2:1, 6:4:1, 6:3:2 or 7:2:2, etc.

[0045] Preferably, the wood pulp comprises unbleached kraft pulp (UKP).

[0046] Preferably, the straw pulp comprises Spanish straw pulp.

[0047] Preferably, the weight proportion of the pulp fiber is 90 to 100 parts (for example, 91 parts, 92 parts, 93 parts, 94 parts, 95 parts, 96 parts, 97 parts, 98 parts or 99 parts, etc.), the weight proportion of the cationic waterproofing agent is 1 to 5 parts (for example, 1.5 parts, 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts or 4.5 parts, etc.), and the weight proportion of the modified poplar fiber is 1 to 10 parts (for example, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts or 9 parts, etc.).

[0048] Preferably, the first mixing further comprises mixing with synthetic fibers.

[0049] Preferably, the synthetic fibers include carbon fibers and / or aramid fibers.

[0050] Preferably, the weight proportion of the synthetic fiber is 0.2 to 3 parts, for example, 0.5 parts, 0.8 parts, 1.1 parts, 1.4 parts, 1.7 parts, 2 parts, 2.3 parts, 2.6 parts or 2.9 parts.

[0051] In the present invention, adding synthetic fibers can further increase the Young's modulus of the speaker cone.

[0052] Preferably, the cationic waterproofing agent comprises a cationic emulsion.

[0053] Preferably, the cationic emulsion comprises a cationic styrene acrylic emulsion and / or a cationic paraffin emulsion.

[0054] In the present invention, the addition of cationic emulsion can improve the overall waterproof performance of the speaker paper cone, and at the same time, the pulp fiber and the modified poplar fiber can be better combined by relying on the positive charge effect of the cationic emulsion.

[0055] Preferably, the preparation method comprises the following steps: performing a first decomposition on pulp fibers, performing a second decomposition by adding a cationic waterproofing agent, performing a third decomposition by adding modified poplar fibers, forming, and hot pressing to obtain the speaker cone.

[0056] Preferably, the first deflaking, the second deflaking and the third deflaking are each independently performed in a deflaking machine.

[0057] Preferably, the rotation speeds of the first deflaking, the second deflaking and the third deflaking are each independently 2000-3000 rpm, for example, 2100 rpm, 2200 rpm, 2300 rpm, 2400 rpm, 2500 rpm, 2600 rpm, 2700 rpm, 2800 rpm or 2900 rpm.

[0058] Preferably, the first decongestion time is 1 to 3 minutes, for example, 1.2 minutes, 1.4 minutes, 1.6 minutes, 1.8 minutes, 2.0 minutes, 2.2 minutes, 2.4 minutes, 2.6 minutes, 2.8 minutes, etc.

[0059] Preferably, the second decongestion time is 1 to 2 minutes, for example, 1.1 minutes, 1.2 minutes, 1.3 minutes, 1.4 minutes, 1.5 minutes, 1.6 minutes, 1.7 minutes, 1.8 minutes or 1.9 minutes.

[0060] Preferably, the third decongestion time is 2 to 3 minutes, for example, 2.1 minutes, 2.2 minutes, 2.3 minutes, 2.4 minutes, 2.5 minutes, 2.6 minutes, 2.7 minutes, 2.8 minutes or 2.9 minutes.

[0061] Preferably, the temperature of the hot pressing is 160-180°C, for example, 162°C, 164°C, 166°C, 168°C, 170°C, 172°C, 174°C, 176°C or 178°C.

[0062] Preferably, the hot pressing time is 40 to 60 seconds, for example, 42 seconds, 44 seconds, 46 seconds, 48 ​​seconds, 50 seconds, 52 seconds, 54 seconds, 56 seconds or 58 seconds.

[0063] In a fourth aspect, the present invention provides a speaker paper cone, which is manufactured using the preparation method described in the third aspect.

[0064] In a fifth aspect, the present invention provides a use of the modified poplar fiber as described in the second aspect or the speaker cone as described in the fourth aspect in preparing a speaker.

[0065] Compared with the prior art, the present invention has at least the following beneficial effects:

[0066] The modified poplar fiber of the present invention has the characteristics of uniform size and good hydrophobicity. When used in the preparation of speaker cones, the modified poplar fiber can be tightly bonded with pulp fibers, reducing moisture absorption, and can simultaneously improve the waterproof and moisture-proof effect and Young's modulus of the speaker cone, increase the damping performance, and apply the prepared speaker cone to speaker products. It can reduce the distortion caused by the cone splitting vibration, reduce the distortion in the mid-high frequency, and make the sound quality pure, smooth, natural and delicate. The density of the speaker cone is ≤0.74g / cm 3 The Young's modulus of the speaker cone is ≥3.42 GPa, and the Young's modulus retention rate of the speaker cone after being placed under constant temperature and humidity conditions of 85° C. and 85% for 48 hours is ≥86%. DETAILED DESCRIPTION

[0067] 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.

[0068] The raw materials used in the following examples and comparative examples are as follows:

[0069] Poplar wood silk: Sourced from Dongguan Yiyuan Craft Products Co., Ltd.

[0070] Beating enzyme: Beating enzyme TF-EB product from Zhejiang Chuanhua Huayang Chemical Co., Ltd.

[0071] Wood pulp: Unbleached sulfate wood pulp, brand FUKP, sourced from Guangzhou Yunqi Electroacoustic Technology Development Co., Ltd.

[0072] Hemp pulp: Manila hemp pulp, sourced from Guangzhou Yunqi Electroacoustic Technology Development Co., Ltd.

[0073] Straw pulp: Spanish straw pulp, sourced from Guangzhou Yunqi Electroacoustic Technology Development Co., Ltd.

[0074] Cationic styrene acrylic emulsion: brand YQF waterproofing agent, from Guangzhou Yunqi Electroacoustic Technology Development Co., Ltd.

[0075] Cationic paraffin emulsion: brand KSJ waterproofing agent, sourced from Guangzhou Yunqi Electroacoustic Technology Development Co., Ltd.

[0076] Example 1

[0077] The present embodiment provides a modified poplar fiber and a preparation method thereof, the preparation method of the modified poplar fiber comprising the following steps: cutting poplar fibers to an average length of 1.5 cm, beating them once in a pulper, wherein the first beating is light knife beating, the beating time is 1.5 h, the beating concentration is 3%, the solvent is water, and then washing and filtering with water to obtain dissociated poplar fibers; weighing 100 g of the dissociated poplar fibers, beating them twice in a pulper under the condition of adding a beating enzyme, wherein the second beating is light knife beating, the amount of beating enzyme used is 8 mg, the beating time is 0.8 h, the beating concentration is 10%, and then washing and filtering with water to obtain split poplar fibers, screening the split poplar fibers using a flat vibrating screen to remove oversized fibers, the screen gap of the flat screen being 0.25 mm, drying the screened fibers at 60° C., and then immersing them in a hydrophobic treatment solution for ultrasonic treatment for 20 min, filtering and naturally drying to obtain the modified poplar fibers;

[0078] The hydrophobic treatment liquid is a mixed aqueous solution of sodium lignin sulfonate and nanocellulose, wherein the mass percentage of sodium lignin sulfonate is 1% and the mass percentage of nanocellulose (average diameter of 20 nm, average length of 300 nm) is 0.25%.

[0079] Example 2

[0080] The present embodiment provides a modified poplar fiber and a preparation method thereof, the preparation method of the modified poplar fiber comprising the following steps: cutting poplar fibers to an average length of 1 cm, beating them once in a pulper, wherein the first beating is light knife beating, the beating time is 2 hours, the beating concentration is 2%, the solvent is water, and then washing and filtering with water to obtain dissociated poplar fibers; weighing 100 g of the dissociated poplar fibers, beating them twice in a pulper under the condition of adding a beating enzyme, wherein the second beating is light knife beating, the amount of beating enzyme used is 8 mg, the beating time is 0.5 hours, the beating concentration is 15%, and then washing and filtering with water to obtain split poplar fibers, screening the split poplar fibers using a flat vibrating screen to remove oversized fibers, the screen gap of the flat screen being 0.2 mm, drying the screened fibers at 50° C., and then immersing them in a hydrophobic treatment solution for ultrasonic treatment for 15 minutes, filtering and naturally drying to obtain the modified poplar fibers;

[0081] The hydrophobic treatment liquid is a mixed aqueous solution of sodium lignin sulfonate and nanocellulose, wherein the mass percentage of sodium lignin sulfonate is 2% and the mass percentage of nanocellulose (average diameter of 12 nm, average length of 250 nm) is 0.5%.

[0082] Example 3

[0083] The present embodiment provides a modified poplar fiber and a preparation method thereof, the preparation method of the modified poplar fiber comprising the following steps: cutting poplar fibers to an average length of 2 cm, beating them once in a pulper, wherein the first beating is light knife beating, the beating time is 1 hour, the beating concentration is 5%, and the solvent is water, and then washing and filtering with water to obtain dissociated poplar fibers; weighing 100 g of the dissociated poplar fibers, beating them twice in a pulper under the condition of adding a beating enzyme, wherein the second beating is light knife beating, the amount of beating enzyme used is 8 mg, the beating time is 1 hour, and the beating concentration is 8%, and then washing and filtering with water to obtain split poplar fibers, screening the split poplar fibers using a flat vibrating screen to remove oversized fibers, the screen gap of the flat screen being 0.3 mm, drying the screened fibers at 80° C., and then immersing them in a hydrophobic treatment solution for ultrasonic treatment for 30 minutes, filtering and naturally drying to obtain the modified poplar fibers;

[0084] The hydrophobic treatment liquid is a mixed aqueous solution of sodium lignin sulfonate and nanocellulose, wherein the mass percentage of sodium lignin sulfonate is 0.5%, and the mass percentage of nanocellulose (average diameter of 25 nm, average length of 350 nm) is 0.1%.

[0085] Example 4

[0086] This embodiment provides a modified poplar fiber and a preparation method thereof. The difference between this embodiment and embodiment 1 is that nanocellulose is not added to the hydrophobic treatment liquid, and other conditions are the same as those in embodiment 1.

[0087] Comparative Example 1

[0088] This comparative example provides a modified poplar fiber and a preparation method thereof. The difference between this comparative example and Example 1 is that no lignin is added to the hydrophobic treatment liquid, and other conditions are the same as those in Example 1.

[0089] Comparative Example 2

[0090] This comparative example provides a modified poplar fiber and a preparation method thereof. The difference between the comparative example and Example 1 is that the preparation of the modified poplar fiber does not include the step of adding a beating enzyme for secondary beating, and other conditions are the same as those in Example 1.

[0091] Comparative Example 3

[0092] This comparative example provides a modified poplar fiber and a preparation method thereof. The difference between this comparative example and Example 1 is that the preparation of the modified poplar fiber does not include the steps of immersing the modified poplar fiber in a hydrophobic treatment liquid for ultrasonic treatment and naturally drying after filtration. Other conditions are the same as those in Example 1.

[0093] Comparative Example 4

[0094] This comparative example provides a modified poplar fiber and a preparation method thereof. The difference between this comparative example and Example 1 is that the preparation of the modified poplar fiber does not include the step of screening the pulp using a flat vibrating screen, and other conditions are the same as those in Example 1.

[0095] Application Example 1

[0096] This application example provides a speaker cone and a preparation method thereof. The raw materials for preparing the speaker cone include the following components in parts by weight: 95 parts of pulp fiber, 3 parts of a cationic waterproofing agent (cationic styrene-acrylic emulsion), and 5 parts of modified poplar fiber (the modified poplar fiber provided in Example 1);

[0097] The pulp fibers include wood pulp (unbleached sulfate wood pulp), hemp pulp (Manila hemp pulp) and straw pulp (Spanish straw pulp) in a mass ratio of 6:3:1.

[0098] The preparation method comprises the following steps: adding wood pulp, hemp pulp and straw pulp into a deflaking machine at a rotation speed of 2500 rpm to perform a first deflaking, adding water during the deflaking to a pulp mass concentration of 5%, and the deflaking time is 2 minutes, adding a cationic waterproofing agent to perform a second deflaking, and the deflaking time is 2 minutes, adding modified poplar fiber to perform a third deflaking, and the deflaking time is 3 minutes, achieving sufficient deflaking to obtain a mixed pulp, and then filtering the mixed pulp on a papermaking machine for forming, and hot pressing at 170°C for 50 seconds for drying to obtain the speaker paper cone.

[0099] Application Example 2

[0100] This application example provides a speaker cone and a preparation method thereof. The raw materials for preparing the speaker cone include the following components by weight: 90 parts of pulp fiber, 5 parts of a cationic waterproofing agent (cationic styrene-acrylic emulsion), and 10 parts of modified poplar fiber (the modified poplar fiber provided in Example 1).

[0101] The pulp fibers include wood pulp (unbleached sulfate wood pulp), hemp pulp (Manila hemp pulp) and straw pulp (Spanish straw pulp) in a mass ratio of 6:3:1.

[0102] The preparation method comprises the following steps: adding wood pulp, hemp pulp and straw pulp into a deflaking machine at a rotation speed of 2000 rpm to perform a first deflaking, adding water during the deflaking to a pulp mass concentration of 5%, and the deflaking time is 3 minutes, adding a cationic waterproofing agent to perform a second deflaking, and the deflaking time is 2 minutes, adding modified poplar fiber to perform a third deflaking, and the deflaking time is 3 minutes, achieving sufficient deflaking to obtain a mixed pulp, and then filtering the mixed pulp on a papermaking machine for forming, and hot pressing at 180°C for 40 seconds for drying to obtain the speaker paper cone.

[0103] Application Example 3

[0104] This application example provides a speaker cone and a preparation method thereof. The raw materials for preparing the speaker cone include the following components by weight: 100 parts of pulp fiber, 1 part of a cationic waterproofing agent (cationic styrene-acrylic emulsion), and 1 part of modified poplar fiber (the modified poplar fiber provided in Example 1).

[0105] The pulp fibers include wood pulp (unbleached kraft pulp), hemp pulp (Manila hemp pulp) and straw pulp (Spanish straw pulp) in a mass ratio of 6:3:1.

[0106] The preparation method includes the following steps: adding wood pulp, hemp pulp and straw pulp into a deflaking machine at a rotation speed of 3000 rpm to perform the first deflaking, adding water during the deflaking to a pulp mass concentration of 5%, and the deflaking time is 1 minute, adding a cationic waterproofing agent for the second deflaking, and the deflaking time is 1 minute, adding modified poplar fiber for the third deflaking, and the deflaking time is 2 minutes to achieve sufficient deflaking to obtain a mixed pulp, and then filtering the mixed pulp on a papermaking machine for forming, and hot pressing at 160°C for 60 seconds to obtain the speaker paper cone.

[0107] Application Example 4

[0108] This application example provides a speaker cone and a preparation method thereof. The difference between this application example and application example 1 is that the raw materials for preparing the speaker cone include the following components, calculated by weight: 95 parts of pulp fiber, 3 parts of a cationic waterproofing agent (cationic styrene-acrylic emulsion), and 5 parts of modified poplar fiber (the modified poplar fiber provided in Example 2);

[0109] The pulp fibers include wood pulp (unbleached kraft pulp), hemp pulp (Manila hemp pulp) and straw pulp (Spanish straw pulp) in a mass ratio of 5:4:1.

[0110] Other conditions are the same as those in Application Example 1.

[0111] Application Example 5

[0112] This application example provides a speaker cone and a preparation method thereof. The difference between this application example and application example 1 is that the raw materials for preparing the speaker cone include the following components, calculated by weight: 95 parts of pulp fiber, 3 parts of a cationic waterproofing agent (cationic styrene-acrylic emulsion), and 5 parts of modified poplar fiber (the modified poplar fiber provided in Example 3);

[0113] The pulp fibers include wood pulp (unbleached kraft pulp), hemp pulp (Manila hemp pulp) and straw pulp (Spanish straw pulp) in a mass ratio of 7:2:2.

[0114] Other conditions are the same as those in Application Example 1.

[0115] Application Example 6

[0116] This application example provides a speaker cone and a method for preparing the same. The raw materials for preparing the speaker cone include the following components, measured by weight: 92 parts of pulp fiber, 3 parts of synthetic fiber (carbon fiber, average length 5 mm, average diameter 7 μm), 3 parts of a cationic waterproofing agent (cationic styrene-acrylic emulsion), and 5 parts of modified poplar fiber (modified poplar fiber provided in Example 1);

[0117] The pulp fibers include wood pulp (unbleached sulfate wood pulp), hemp pulp (Manila hemp pulp) and straw pulp (Spanish straw pulp) in a mass ratio of 6:3:1.

[0118] The preparation method comprises the following steps: adding wood pulp, hemp pulp, straw pulp and synthetic fiber into a deflaking machine at a rotation speed of 2500 rpm to perform a first deflaking, adding water during the deflaking to a pulp mass concentration of 5%, and the deflaking time is 2 minutes, adding a cationic waterproofing agent to perform a second deflaking, and the deflaking time is 2 minutes, adding modified poplar fiber to perform a third deflaking, and the deflaking time is 3 minutes, achieving sufficient deflaking to obtain a mixed pulp, and then filtering the mixed pulp on a papermaking machine for forming, and hot pressing at 170°C for 50 seconds for drying to obtain the speaker paper cone.

[0119] Application Example 7

[0120] This application example provides a speaker cone and a method for preparing the same. The raw materials for preparing the speaker cone include the following components, measured by weight: 95 parts of pulp fiber, 0.2 parts of synthetic fiber (aramid fiber, average length 5 mm, average diameter 12 μm), 3 parts of a cationic waterproofing agent (cationic styrene-acrylic emulsion), and 5 parts of modified poplar fiber (modified poplar fiber provided in Example 1);

[0121] The pulp fibers include wood pulp (unbleached sulfate wood pulp), hemp pulp (Manila hemp pulp) and straw pulp (Spanish straw pulp) in a mass ratio of 6:3:1.

[0122] The preparation method comprises the following steps: adding wood pulp, hemp pulp, straw pulp and synthetic fiber into a deflaking machine at a rotation speed of 2500 rpm to perform a first deflaking, adding water during the deflaking to a pulp mass concentration of 5%, and the deflaking time is 2 minutes, adding a cationic waterproofing agent to perform a second deflaking, and the deflaking time is 2 minutes, adding modified poplar fiber to perform a third deflaking, and the deflaking time is 3 minutes, achieving sufficient deflaking to obtain a mixed pulp, and then filtering the mixed pulp on a papermaking machine for forming, and hot pressing at 170°C for 50 seconds for drying to obtain the speaker paper cone.

[0123] Application Example 8

[0124] This application example provides a speaker cone and a preparation method thereof. The difference between this application example and application example 1 is that the raw materials for preparing the speaker cone include the following components, calculated by weight: 92 parts of pulp fiber, 3 parts of a cationic waterproofing agent (cationic paraffin emulsion), and 8 parts of modified poplar fiber (the modified poplar fiber provided in Example 1);

[0125] The pulp fiber is wood pulp (unbleached kraft pulp).

[0126] Other conditions are the same as those in Application Example 1.

[0127] Application Example 9

[0128] This application example provides a speaker cone and a preparation method thereof. The difference between this application example and application example 1 is that the raw materials for preparing the speaker cone include the following components by weight: 97 parts of pulp fiber, 3 parts of a cationic waterproofing agent (cationic paraffin emulsion), and 3 parts of modified poplar fiber (the modified poplar fiber provided in Example 1);

[0129] The pulp fiber is hemp pulp (Manila hemp pulp).

[0130] Other conditions are the same as those in Application Example 1.

[0131] Application Example 10

[0132] This application example provides a speaker cone and a preparation method thereof. The difference between this application example and application example 1 is that the raw materials for preparing the speaker cone include the following components in parts by weight: 95 parts of pulp fiber, 3 parts of a cationic waterproofing agent (cationic paraffin emulsion), and 5 parts of modified poplar fiber (the modified poplar fiber provided in Example 1);

[0133] The pulp fiber is straw pulp (Spanish straw pulp).

[0134] Other conditions are the same as those in Application Example 1.

[0135] Application Example 11

[0136] This application example provides a speaker paper cone and a preparation method thereof. The difference between this application example and application example 1 is that the modified poplar fiber (the modified poplar fiber provided in Example 1) is replaced with modified poplar fiber of the same quality (the modified poplar fiber provided in Example 4), and other conditions are the same as those in application example 1.

[0137] Comparative Application Example 1

[0138] This comparative application example provides a speaker paper cone and a preparation method thereof. The difference between it and Application Example 1 is that the modified poplar fiber (the modified poplar fiber provided in Example 1) is replaced with modified poplar fiber of the same quality (the modified poplar fiber provided in Comparative Example 1), and other conditions are the same as those in Application Example 1.

[0139] Comparative Application Example 2

[0140] This comparative application example provides a speaker paper cone and a preparation method thereof. The difference between it and Application Example 1 is that the modified poplar fiber (the modified poplar fiber provided in Example 1) is replaced with modified poplar fiber of the same quality (the modified poplar fiber provided in Comparative Example 2), and other conditions are the same as those in Application Example 1.

[0141] Comparative Application Example 3

[0142] This comparative application example provides a speaker paper cone and a preparation method thereof. The difference between it and Application Example 1 is that the modified poplar fiber (the modified poplar fiber provided in Example 1) is replaced with modified poplar fiber of the same quality (the modified poplar fiber provided in Comparative Example 3), and other conditions are the same as those in Application Example 1.

[0143] Comparative Application Example 4

[0144] This comparative application example provides a speaker paper cone and a preparation method thereof. The difference between it and Application Example 1 is that the modified poplar fiber (the modified poplar fiber provided in Example 1) is replaced with modified poplar fiber of the same quality (the modified poplar fiber provided in Comparative Example 4), and other conditions are the same as those in Application Example 1.

[0145] Comparative Application Example 5

[0146] This comparative application example provides a speaker paper cone and a preparation method thereof. The difference between this comparative application example and application example 1 is that no cationic waterproofing agent is added in the preparation of the speaker paper cone, and other conditions are the same as those in application example 1.

[0147] Comparative Application Example 6

[0148] This comparative application example provides a speaker paper cone and a preparation method thereof. The difference between it and Application Example 1 is that the preparation method includes the following steps: adding wood pulp, hemp pulp, straw pulp, modified poplar fiber, and cationic waterproofing additive into a deflaking machine and deflaking at a speed of 2500 rpm for 7 minutes, then filtering the mixed pulp on a papermaking machine for forming, and hot pressing at 170°C for 50 seconds for drying to obtain the speaker paper cone. Other conditions are the same as those in Application Example 1.

[0149] Comparative Application Example 7

[0150] This comparative application example provides a speaker paper cone and a preparation method thereof. The difference between this comparative application example and application example 1 is that modified poplar wood fiber is not added in the preparation of the speaker paper cone, and other conditions are the same as those in application example 1.

[0151] The lengths and diameters of the modified poplar fibers obtained in Examples 1 to 4 and Comparative Examples 1 to 4 are shown in Table 1 below.

[0152] Table 1

[0153] Length (mm) Diameter (mm) Example 1 0.3～3.0 0.05～0.18 Example 2 0.3～1.5 0.03～0.15 Example 3 0.3～4.5 0.05～0.20 Example 4 0.3～3.0 0.05～0.15 Comparative Example 1 0.3～3.0 0.05～0.16 Comparative Example 2 0.5～5.0 0.10～0.20 Comparative Example 3 0.3～3.0 0.05～0.15 Comparative Example 4 0.1～6.0 0.05～0.50

[0154] The following performance tests were conducted on the speaker cones provided for use cases 1 to 11 and comparative application examples 1 to 7.

[0155] (1) Density: Measure the mass of the sample using an analytical balance; measure the thickness of the sample using a thickness gauge, and take the average value of the thickness of the same sample three times; calculate the sample density;

[0156] (2) Young's modulus: Young's modulus was measured using the three-point bending method;

[0157] (3) Retention rate of Young's modulus after high temperature and high humidity: The samples were placed in a constant temperature and humidity condition of 85°C and 85% for 48 h, and then the ratio of the Young's modulus of the sample after high temperature and high humidity treatment to the Young's modulus before treatment was measured by the three-point bending method.

[0158] The test results are shown in Table 2 below.

[0159] Table 2

[0160]

[0161]

[0162] The test results show that: from application examples 1 to 11, it can be seen that the density of the speaker cone prepared by the present invention is 0.65 to 0.74 g / cm 3 A Young's modulus of ≥3.42GPa and a Young's modulus retention rate of ≥86% after high temperature and high humidity can be achieved, with the technical effects of low density, high Young's modulus and excellent resistance to high temperature and high humidity.

[0163] Compared with Application Example 6 and Application Example 7, the Young's modulus of the speaker cone prepared by adding carbon fiber and aramid fiber is increased, the Young's modulus retention rate is high after high temperature and high humidity, the stability is good, the impact of the environment is small, the moisture absorption is low, the high-frequency response is smoother, the distortion is significantly reduced, and the sound quality is pure and natural.

[0164] It can be seen from Application Examples 1 and 11 that if nanocellulose is not added in the preparation of modified poplar wood fiber, although it can still maintain good high temperature and high humidity resistance, the lack of the filling and bridging effect of nanocellulose greatly affects the bonding between fibers, and the Young's modulus of the prepared speaker paper cone decreases significantly.

[0165] It can be seen from Application Example 1 and Comparative Application Example 1 that if lignin is not added in the preparation of modified poplar wood fiber, the high temperature and high humidity resistance of the prepared speaker paper cone will be significantly reduced.

[0166] It can be seen from Application Example 1 and Comparative Application Example 2 that if the preparation of the modified poplar fiber does not include the addition of pulping enzyme for secondary pulping, the Young's modulus of the prepared speaker cone decreases significantly, mainly because the degree of fibrillation on the surface of the poplar fiber decreases, the bonding strength with the pulp fiber decreases, and the strength decreases.

[0167] It can be seen from Application Example 1 and Comparative Application Example 3 that if the preparation of the modified poplar fiber does not include the steps of immersing it in a hydrophobic treatment liquid for ultrasonic treatment and naturally drying it after filtration, the surface of the poplar fiber of the prepared speaker paper cone will not have a hydrophobic structure, the moisture absorption will increase, and the Young's modulus retention rate will be low after high temperature and high humidity.

[0168] It can be seen from Application Example 1 and Comparative Application Example 4 that if the preparation of the modified poplar wood fiber does not include the use of a flat vibrating screen for pulp screening, the prepared modified poplar wood fibers have large size differences, the prepared speaker paper cones have poor consistency, the tested density increases, the modified poplar wood fibers are poorly bonded to the pulp fibers, the Young's modulus decreases, and the Young's modulus retention rate decreases after high temperature and high humidity.

[0169] It can be seen from Application Example 1 and Comparative Application Example 5 that if no cationic waterproofing agent is added to the raw materials for preparing the speaker paper cone, the Young's modulus of the prepared speaker paper cone will be reduced, and the Young's modulus retention rate will be greatly reduced after high temperature and high humidity.

[0170] It can be seen from Application Example 1 and Comparative Application Example 6 that if pulp fiber, modified poplar fiber, and cationic waterproofing agent are added together for disintegration, the cationic waterproofing agent is adsorbed on the modified poplar fiber and pulp fiber at the same time, and the charge effect is weakened, which affects the combination of the two to a certain extent. The Young's modulus of the prepared speaker paper cone is reduced, and the Young's modulus retention rate is greatly reduced after high temperature and high humidity.

[0171] It can be seen from Application Example 1 and Comparative Application Example 7 that if modified poplar wood fiber is not added, the Young's modulus of the prepared speaker cone is reduced, the Young's modulus retention rate decreases after high temperature and high humidity, and the sound quality is reduced.

[0172] The applicant declares that the above is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention fall within the scope of protection and disclosure of the present invention.

Claims

1. A method for preparing modified poplar fiber, characterized in that: The preparation method comprises the following steps: beating poplar wood fibers once to obtain dissociated poplar fibers, adding beating enzyme to perform secondary beating to obtain split poplar fibers, screening the pulp, and treating with a hydrophobic treatment liquid to obtain the modified poplar fibers.

2. The preparation method according to claim 1, characterized in that The length of the poplar wood fibers is 1 to 2 cm; Preferably, the first beating is light knife beating, the beating time is 1 to 2 hours, the beating concentration is 2% to 5%, and the solvent is water; Preferably, the secondary beating is light knife beating, the beating time is 0.5 to 1 hour, the beating concentration is 8% to 15%, and the solvent is water; Preferably, the second beating further comprises a water washing step; Preferably, the beating enzyme is a complex enzyme preparation; Preferably, the complex enzyme preparation comprises cellulase and hemicellulase; Preferably, the beating enzyme is used in an amount of 50 to 100 g per ton of dissociated poplar fiber; Preferably, the pulp screening is performed using a flat vibrating screen; Preferably, the screen gap of the flat vibrating screen is 0.2-0.3 mm; Preferably, the method further comprises a drying step after the pulp screening; Preferably, the drying temperature is 50-80°C.

3. The preparation method according to claim 1 or 2, characterized in that The treatment with the hydrophobic treatment liquid is to perform immersion ultrasonic treatment with the hydrophobic treatment liquid; Preferably, the immersion ultrasonic treatment time is 15 to 30 minutes; Preferably, the hydrophobic treatment liquid comprises lignin and water; Preferably, the mass percentage of lignin in the hydrophobic treatment liquid is 0.5% to 2%; Preferably, the hydrophobic treatment liquid further comprises nanocellulose; Preferably, the mass percentage of nanocellulose in the hydrophobic treatment liquid is 0.25% to 1%; Preferably, the average diameter of the nanocellulose is 10 to 30 nm; Preferably, the average length of the nanocellulose is 200 to 400 nm; Preferably, the lignin comprises lignin sulfonate; Preferably, the lignin sulfonate comprises sodium lignin sulfonate and / or calcium lignin sulfonate; Preferably, the treatment with the hydrophobic treatment liquid further includes filtering and drying steps.

4. A modified poplar fiber, characterized in that: The modified poplar fiber is prepared by the preparation method according to any one of claims 1 to 3.

5. The modified poplar fiber according to claim 4, characterized in that The length of the modified poplar fiber is 0.3 to 5 mm; Preferably, the diameter of the modified poplar fiber is 0.03-0.2 mm.

6. A method for preparing a speaker cone, characterized in that: The preparation method comprises the following steps: first mixing pulp fiber and a cationic waterproofing agent, and then second mixing the pulp fiber with the modified poplar fiber according to claim 4 or 5 to obtain the speaker cone.

7. The preparation method according to claim 6, characterized in that The pulp fiber includes any one of wood pulp, hemp pulp or straw pulp, or a combination of at least two of them; Preferably, the mass ratio of wood pulp, hemp pulp and straw pulp in the pulp fiber is (5-7): (2-4): (1-2); Preferably, the weight portion of the pulp fiber is 90 to 100 parts, the weight portion of the cationic waterproofing agent is 1 to 5 parts, and the weight portion of the modified poplar fiber is 1 to 10 parts; Preferably, said first mixing further comprises mixing with synthetic fibers; Preferably, the synthetic fibers include carbon fibers and / or aramid fibers; Preferably, the weight portion of the synthetic fiber is 0.2 to 3 parts; Preferably, the cationic waterproofing agent comprises a cationic emulsion; Preferably, the cationic emulsion comprises a cationic styrene acrylic emulsion and / or a cationic paraffin emulsion.

8. The preparation method according to claim 6 or 7, characterized in that: The preparation method comprises the following steps: performing a first decomposition of pulp fibers, adding a cationic waterproofing agent to perform a second decomposition, adding modified poplar fibers to perform a third decomposition, forming, and hot pressing to obtain the speaker cone; Preferably, the first deflaking, the second deflaking and the third deflaking are each independently performed in a deflaking machine; Preferably, the rotation speeds of the first deflaking, the second deflaking and the third deflaking are independently 2000-3000 rpm; Preferably, the first decongestion time is 1 to 3 minutes; Preferably, the second decongestion time is 1 to 2 minutes; Preferably, the third decongestion time is 2 to 3 minutes; Preferably, the temperature of the hot pressing is 160-180°C; Preferably, the hot pressing time is 40 to 60 seconds.

9. A speaker cone, characterized in that: The speaker cone is made by the preparation method according to any one of claims 6 to 8.

10. Use of the modified poplar fiber according to claim 4 or 5 or the speaker cone according to claim 9 in preparing a speaker.

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