阅读说明：本技术 一种磁片及其制备方法 (A kind of magnetic sheet and preparation method thereof ) 是由 肖时勇 苏艳锋 卢飞翔 於扬栋 杜阳忠 于 2019-09-18 设计创作，主要内容包括：本发明提供了一种磁片及其制备方法。所述制备方法包括：1)将分散剂、溶剂和铁氧体材料混合,进行破碎,得到一次破碎料；2)将一次破碎料与增塑剂和粘结剂混合,进行破碎,得到二次破碎料；3)对二次破碎料进行脱泡,得到磁片浆料；4)对磁片浆料进行流延和烧结,得到所述磁片。本发明提供的制备方法通过优化流延浆料的加料顺序和流延浆料配方,与流延工艺的温度和流流速,以及烧结工艺的具体条件相配合,有效地解决了薄型磁片(在0.1mm以下)烧结翘曲的问题,大大提升产品的良品率。本发明提供的磁片具有较高的磁导率实部,性能良好,可用于无线充电领域。(The present invention provides a kind of magnetic sheets and preparation method thereof.The preparation method includes: 1) to mix dispersing agent, solvent and Ferrite Material, is crushed, obtains primary fragmentation material；2) primary fragmentation material is mixed with plasticizer and binder, is crushed, obtain second-time breakage material；3) deaeration is carried out to second-time breakage material, obtains magnetic sheet slurry；4) magnetic sheet slurry is cast and is sintered, obtain the magnetic sheet.The charging sequence and casting slurry formula that preparation method provided by the invention passes through optimization casting slurry, with the temperature and stream flow velocity of casting technique, and the actual conditions of sintering process match, it efficiently solves the problems, such as that slim magnetic sheet (in 0.1mm or less) is sintered warpage, greatly promotes the yields of product.Magnetic sheet magnetic conductivity real part with higher provided by the invention, it is functional, it can be used for wireless charging field.)

1. a kind of magnetic sheet preparation method, which is characterized in that the described method includes:

(1) dispersing agent, solvent and Ferrite Material are mixed, is crushed, obtains primary fragmentation material；

(2) step (1) the primary fragmentation material is mixed with plasticizer and binder, is crushed, obtains second-time breakage material；

(3) deaeration is carried out to step (2) the second-time breakage material, obtains magnetic sheet slurry；

(4) step (3) the magnetic sheet slurry is cast and is sintered, obtain the magnetic sheet.

2. preparation method according to claim 1, which is characterized in that step (1) described dispersing agent includes unsaturated fat Acid dispersant and/or non-ionic dispersing agent；

Preferably, step (1) solvent is organic solvent；

Preferably, the organic solvent includes any one in dehydrated alcohol, isopropanol, ethyl acetate or butanone or at least two The combination of kind；

Preferably, step (1) Ferrite Material is dusty material；

Preferably, step (1) described Ferrite Material includes nickel zinc copper ferrite and/or manganese-zinc ferrite；

Preferably, step (1) the broken method is ball milling；

Preferably, step (1) method for mixing dispersing agent, solvent and Ferrite Material are as follows: by dispersing agent, solvent and iron Oxysome sequentially adds mixing.

3. preparation method according to claim 1 or 2, which is characterized in that step (2) described thickener includes O-phthalic Esters of gallic acid thickener and/or glycols thickener；

Preferably, step (2) described binder includes any one in polyvinyl butyral, acrylic resin or polyvinyl alcohol Kind or at least two combination；

Preferably, step (2) the broken method is ball milling；

Preferably, step (2) method for mixing step (1) the primary fragmentation material with plasticizer and binder are as follows: to Thickener and binder are sequentially added in step (1) the primary fragmentation material.

4. preparation method according to any one of claim 1-3, which is characterized in that in step (1) and step (2), institute State Ferrite Material, dispersing agent, binder, thickener mass ratio be 200:(1~2): (6~10): (2~6).

5. preparation method described in any one of -4 according to claim 1, which is characterized in that step (3) deaeration is vacuum Deaeration；

Preferably, the time of the vacuum defoamation is 0.4-0.6h/L；

Preferably, the solid content of step (3) the magnetic sheet slurry is 60-75wt%；

Preferably, step (3) further include: before deaeration, auxiliary agent is added into step (2) the second-time breakage material；

Preferably, the auxiliary agent is levelling agent；

Preferably, the levelling agent includes in castor oil, silicone emulsion, nonionic acrylic copolymer or butyl cellulose Any one or at least two combination；

Preferably, the mass ratio of the auxiliary agent and step (1) described Ferrite Material is (0.2~0.3): 1.

6. preparation method according to any one of claims 1-5, which is characterized in that the speed of step (4) described curtain coating For 0.5-2m/min；

Preferably, the scraper height of step (4) described curtain coating is 80-200 μm；

Preferably, during step (4) described curtain coating, the direction moved along slurry successively sets four temperature ranges, the One silicon carbide is 30-45 DEG C, and second interval temperature is 50-60 DEG C, and 3rd interval temperature is 70-90 DEG C, the 4th silicon carbide It is 65-80 DEG C；

Preferably, the drying time of step (4) described curtain coating is 0.5-3h.

7. preparation method according to claim 1 to 6, which is characterized in that the temperature of step (4) described sintering It is 950-1200 DEG C；

Preferably, the time of step (4) described sintering is 1-8h；

Preferably, step (4) is described is sintered to balanced atmosphere sintering.

8. preparation method described in any one of -7 according to claim 1, which is characterized in that step (4) further include: curtain coating obtains Product be first sliced before sintering.

9. preparation method according to claim 1 to 8, which is characterized in that the described method comprises the following steps:

(1) dispersing agent, organic solvent and ferrite are sequentially added into ball mill, carries out ball milling, obtains primary fragmentation material；

(2) thickener and binder are sequentially added into step (1) the primary fragmentation material, are carried out ball milling, are obtained second-time breakage Material；

The Ferrite Material, dispersing agent, binder, thickener mass ratio be 200:(1~2): (6~10): (2~6)；

(3) auxiliary agent is added into step (2) the second-time breakage material, then carries out vacuum defoamation, the time of vacuum defoamation is 0.4- 0.6h/L, obtains magnetic sheet slurry, and the solid content of the magnetic sheet slurry is 60-75wt%；

The mass ratio of the auxiliary agent and step (1) described Ferrite Material is (0.2~0.3): 1；

(4) step (3) the magnetic sheet slurry is cast, is sliced, and be balanced atmosphere sintering 1- at 950-1200 DEG C 8h obtains the magnetic sheet；

The speed of the curtain coating is 0.5-2m/min, and the scraper height of the curtain coating is 80-200 μm, during the curtain coating, The direction moved along slurry successively sets four temperature ranges, and first interval temperature is 30-45 DEG C, and second interval temperature is 50-60 DEG C, 3rd interval temperature is 70-90 DEG C, and the 4th silicon carbide is 65-80 DEG C, the drying time of step (4) described curtain coating For 0.5-3h.

10. a kind of magnetic sheet that preparation method as claimed in any one of claims 1-9 wherein obtains.

Technical field

The invention belongs to the invention belongs to technical field of magnetic materials, be related to a kind of magnetic sheet and preparation method thereof.

Background technique

With the development of electronic communication industry, certain electronic products such as mobile phone is continuous such as wireless charging due to its function Powerful and perfect, especially external some developed countries, wireless charging module has become the factory standard configuration of mobile phone.In order to meet people It is growing to more convenient, more efficiently consumption demand, the research of the magnetic sheet for wireless charging is gradually paid close attention to by people And pay attention to.Since modern electronic product develops towards small, thin, light direction, internal structure design will be more and more compacter, this Require the wireless charging magnetic sheet thinner labyrinth requirement to adapt to interior of mobile phone internal for it, it is a kind of thin and electromagnetically The superior wireless charging magnetic sheet of energy also becomes the inevitable outcome of Market Selection.

In wireless charging magnetic sheet generally based on nickel zinc copper ferrite powder raw material, and use film casting technique system At.Specifically, the main body powder at present in wireless charging magnetic sheet slurry includes nickel-copper-zinc ferrite or manganese-zinc ferrite powder etc.； Auxiliary material includes the various auxiliary agents such as solvent, dispersing agent, binder, plasticizer, defoaming agent, levelling agent, then by the slurry using crowded Magnetic sheet is prepared in the mode of molding or compression moulding out.And use squeeze out or compression moulding mode products obtained therefrom general thickness compared with Then (0.3mm or more) greatly makes product reach required thickness by post-processing mode, lead to process flow length, raw material availability It is low；And since material brittleness itself is high, yield loss is larger during post-processing.And the slurry is directlyed adopt into tape casting side When formula, blank thickness direction upper density is caused not since prepared by slurry and store and is cast powder sedimentation in wet film drying process , easily occur in sintering process shrinking percentage it is inconsistent caused by the undesirable conditions such as cracking, warpage, and easily cause the burning of larger area Warpage is tied, keeps product yield low.

CN105682438A discloses a kind of high magnetic permeability and inhales wave plate and its casting slurry and preparation method, the stream of the program Prolong slurrying formula to be made of soft magnetism powder, plasticizer, dispersing agent and organic insulation elastomer, which can be improved powder The characteristics such as magnetic conductivity and reduction loss, but wherein have organic insulation elastomer, this will cause environmental pollution, and yields is also Wait improve.

CN103833340A discloses a kind of NFC magnetic sheet slurry and NFC magnetic sheet, and the program introduces benzene kind solvent, and straight When connecing using casting arrangement, cause blank thick since prepared by slurry and store and is cast powder sedimentation in wet film drying process It is uneven to spend direction upper density, easily causes the sintering warpage of larger area, keeps product yield not high.

CN105541314A discloses a kind of preparation method of ferrite sheet material, comprising: by ferromagnetic oxide powder, dispersing agent, Binder, plasticizer and solvent are uniformly mixed to form slurry；Ferrite raw cook is made in slurry curtain coating；By the ferrite Raw cook drying successively stacks according to the sequence of roughening medium, the ferrite raw cook, roughening medium, steel plate and is packed into packaging bag In, vacuum sealing；After the packaged ferrite raw cook is pressed roughening, the ferrite raw cook of roughening is taken out；It will be more The ferrite raw cook of piece roughening stacks, and is placed on load bearing board, carries out dumping and sintering, obtains ferrite sheet material.But The ferrite product yields that this method obtains need to be improved.

Summary of the invention

In view of the deficiencies of the prior art, the present invention intends to provide a kind of magnetic sheet and preparation method thereof.This hair The preparation method of bright offer is optimized by the collaboration to pulping process, casting technique and sintering process, is solved slim magnetic sheet and is burnt The problem that knot warpage causes yields low, while the function admirable of magnetic sheet product.

To achieve this purpose, the present invention adopts the following technical scheme:

In a first aspect, the present invention provides a kind of magnetic sheet preparation method, which comprises

(1) dispersing agent, solvent and Ferrite Material are mixed, is crushed, obtains primary fragmentation material；

(2) step (1) the primary fragmentation material is mixed with plasticizer and binder, is crushed, obtains second-time breakage Material；

(3) deaeration is carried out to step (2) the second-time breakage material, obtains magnetic sheet slurry；

(4) step (3) the magnetic sheet slurry is cast and is sintered, obtain the magnetic sheet.

Preparation method provided by the invention is optimized by the collaboration to pulping process, casting technique and sintering process, is solved The low technical problem of the magnetic sheet product yield of thickness small (in 0.1mm or less) is prepared in the prior art.Pulping process therein LTCC, filter can be applied to, in laminated inductance industry.

Preparation method provided by the invention is by first mixing dispersing agent, solvent and Ferrite Material simultaneously in pulping process It is broken, primary fragmentation material mix with plasticizer and binder again later, can play ball milling disperse not reunite, epigranular work With, mixed compared to by each one step of raw material, have adhesive coated particle uniformly, slurry viscosity, the excellent advantage of mobility.

Defoaming agent is not used in the present invention, such benefit is not influence follow-up sintering technique using mechanical vacuum deaeration.

Fragmentation procedure in the present invention advantageously reduces the powder particle size in slurry, and then shortens sintering time, reduces magnetic Piece cost.

It is used as currently preferred technical solution below, but not as the limitation to technical solution provided by the invention, leads to Following preferred technical solution is crossed, can preferably reach and realize technical purpose and beneficial effect of the invention.

As currently preferred technical solution, step (1) described dispersing agent include unsaturated fat acid dispersant and/or Non-ionic dispersing agent.

Preferably, step (1) solvent is organic solvent.

Preferably, the organic solvent include in dehydrated alcohol, isopropanol, ethyl acetate or butanone any one or extremely Few two kinds of combination.Above-mentioned solvent type is conducive to quickly be cast, and shortens sintering time, and then reduce magnetic sheet production cost.

Preferably, step (1) Ferrite Material is dusty material.

Preferably, step (1) described Ferrite Material includes nickel zinc copper ferrite and/or manganese-zinc ferrite.

Preferably, step (1) the broken method is ball milling.

Preferably, step (1) method for mixing dispersing agent, solvent and Ferrite Material are as follows: by dispersing agent, solvent Mixing is sequentially added with ferrite.Be using this charging sequence because first make dispersing agent uniform dissolution in a solvent, then Add ferrite particle ball milling, its particle is made not reunite, epigranular is conducive to the stability of slurry.

As currently preferred technical solution, step (2) described thickener include phthalate thickener and/ Or glycols thickener.

Preferably, step (2) described binder includes appointing in polyvinyl butyral, acrylic resin or polyvinyl alcohol It anticipates a kind of or at least two combinations.

Preferably, step (2) the broken method is ball milling.

Preferably, step (2) method for mixing step (1) the primary fragmentation material with plasticizer and binder Are as follows: thickener and binder are sequentially added into step (1) the primary fragmentation material.It is because of thickening using this charging sequence Slurry is first dissolved into agent, adds binder, this can make its slurry viscosity appropriate.

It is the Ferrite Material, dispersing agent, viscous in step (1) and step (2) as currently preferred technical solution Tie agent, the mass ratio of thickener is 200:(1~2): (6~10): (2~6), such as 200:1:6:2,200:1:7:3,200: 1.5:8:4,200:2:10:6,200:2:6:2 or 200:1:10:3 etc..

As currently preferred technical solution, step (3) deaeration is vacuum defoamation.

Preferably, the time of the vacuum defoamation be 0.4-0.6h/L, such as 0.4h/L, 0.45h/L, 0.5h/L, 0.55h/L or 0.6h/L etc..In the present invention, if the vacuum defoamation time of unit volume broken material is too short, it will lead in slurry There are also bubble, there is pin hole in this green tape that will lead to curtain coating；If vacuum defoamation overlong time, it will lead to quantity of solvent reduction, make Its slurry viscosity increases, and leads to its cast sheet uneven thickness and cracking phenomena.

Preferably, the solid content of step (3) the magnetic sheet slurry is 60-75wt%.

Preferably, step (3) further include: before deaeration, auxiliary agent is added into step (2) the second-time breakage material.

Preferably, the auxiliary agent is levelling agent.

Preferably, the levelling agent include castor oil, silicone emulsion, nonionic acrylic copolymer (BYK380N) or In butyl cellulose any one or at least two combination.

Preferably, the mass ratio of the auxiliary agent and step (1) described Ferrite Material is (0.2~0.3): 1, such as 0.2: 1,0.23:1,0.25:1,0.28:1 or 0.3:1 etc..

In the present invention, by optimization casting slurry formula in organic system (solvent, dispersing agent, binder, plasticizer with And optional auxiliary agent) in each component type, order of addition and process conditions, help to prepare thickness less than 0.1mm and property The excellent soft magnetic core product of energy, while solving the problems, such as slim magnetic sheet sintering warpage, greatly improve production yield.

As currently preferred technical solution, the speed of step (4) described curtain coating is 0.5-2m/min, such as 0.5m/ Min, 1m/min, 1.5m/min or 2m/min etc..In the present invention, if curtain coating excessive velocities, will lead to cast sheet and do not dry completely It is dry；If it is excessively slow to be cast speed, it will lead to curtain coating green tape cracking, cause production efficiency not high,.In the present invention, using low melting point Solvent is conducive to improve casting rate.

Preferably, the scraper height of step (4) described curtain coating is 80-200 μm, such as 80 μm, 100 μm, 120 μm, 140 μ M, 160 μm, 180 μm or 200 μm etc..

Preferably, during step (4) described curtain coating, the direction moved along slurry successively sets four humidity provinces Between, first interval temperature is 30-45 DEG C, such as 30 DEG C, 32 DEG C, 35 DEG C, 37 DEG C, 40 DEG C, 42 DEG C or 45 DEG C etc., second interval temperature Degree is 50-60 DEG C, such as 50 DEG C, 52 DEG C, 54 DEG C, 56 DEG C, 58 DEG C or 60 DEG C etc., 3rd interval temperature is 70-90 DEG C, such as 70 DEG C, 75 DEG C, 80 DEG C, 85 DEG C or 90 DEG C etc., the 4th silicon carbide is 65-80 DEG C, such as 65 DEG C, 70 DEG C, 72 DEG C, 75 DEG C, 78 DEG C Or 80 DEG C etc..In the present invention, if any silicon carbide of curtain coating is excessively high, slurry excessive evaporation, is opened when will lead to curtain coating Split phenomenon；If any silicon carbide of curtain coating is too low, cast sheet injustice will lead to.

Preferably, the drying time of step (4) described curtain coating is 0.5-3h, such as 0.5h, 1h, 1.5h, 2h, 2.5h or 3h Deng.

As currently preferred technical solution, the temperature of step (4) described sintering is 950-1200 DEG C, such as 950 DEG C, 960 DEG C, 970 DEG C, 980 DEG C, 990 DEG C, 1000 DEG C, 1100 DEG C or 1200 DEG C etc..In the present invention, if the temperature of sintering is excessively high, It will lead to sintered magnetic sheet to be easily broken off；If the temperature of sintering is too low, it is inadequate to will lead to magnetic sheet magnetic conductivity.

Preferably, the time of step (4) described sintering is 1-8h, such as 1h, 2h, 4h, 6h or 8h etc..In the present invention, such as Fruit sintering time is too long, will lead to sintered magnetic sheet cracking and warping phenomenon；If sintering time is too short, magnetic sheet magnetic will lead to Conductance is inadequate.

In the present invention, sintering process is quick, can reduce cost.

Preferably, step (4) is described is sintered to balanced atmosphere sintering.

As currently preferred technical solution, step (4) further include: the product being cast first is cut before sintering Piece.

As the further preferred technical solution of preparation method of the present invention, the described method comprises the following steps:

(1) dispersing agent, organic solvent and ferrite are sequentially added into ball mill, carries out ball milling, obtains primary fragmentation material；

(2) thickener and binder are sequentially added into step (1) the primary fragmentation material, are carried out ball milling, are obtained secondary Broken material；

The Ferrite Material, dispersing agent, binder, thickener mass ratio be 200:(1~2): (6~10): (2~ 6)；

(3) auxiliary agent is added into step (2) the second-time breakage material, then carries out vacuum defoamation, the time of vacuum defoamation is 0.4-0.6h/L, obtains magnetic sheet slurry, and the solid content of the magnetic sheet slurry is 60-75wt%；

The mass ratio of the auxiliary agent and step (1) described Ferrite Material is (0.2~0.3): 1；

(4) step (3) the magnetic sheet slurry is cast, is sliced, and be balanced atmosphere burning at 950-1200 DEG C 1-8h is tied, the magnetic sheet is obtained；

The speed of the curtain coating is 0.5-2m/min, and the scraper height of the curtain coating is 80-200 μm, the mistake of the curtain coating Cheng Zhong, the direction moved along slurry successively set four temperature ranges, and first interval temperature is 30-45 DEG C, second interval temperature Degree is 50-60 DEG C, and 3rd interval temperature is 70-90 DEG C, and the 4th silicon carbide is 65-80 DEG C, the drying of step (4) described curtain coating Time is 0.5-3h.

Second aspect, the present invention provide a kind of magnetic sheet that preparation method obtains as described in relation to the first aspect.The magnetic sheet has Higher magnetic conductivity real part, it is functional, it can be used for wireless charging field.

Compared with prior art, the invention has the following advantages:

(1) preparation method provided by the invention passes through the charging sequence and casting slurry formula of optimization casting slurry, with stream The actual conditions of the temperature and stream flow velocity and sintering process of prolonging technique match, and efficiently solve slim magnetic sheet (In 0.1mm or less) sintering warpage the problem of, greatly promote the yields of product, yields is up to 96%.

(2) magnetic sheet provided by the invention magnetic conductivity real part with higher, functional, magnetic conductivity real part is up to 161.

Specific embodiment

In order to better illustrate the present invention, it is easy to understand technical solution of the present invention, below further specifically to the present invention It is bright.But following embodiments is only simple example of the invention, does not represent or limit the scope of the present invention, this Invention protection scope is subject to claims.

The following are typical but non-limiting embodiments of the invention: