CN103483906B - Soft magnetic ferrite printing ink and application thereof - Google Patents

Abstract

The invention relates to soft magnetic ferrite printing ink and an application thereof. The soft magnetic ferrite printing ink consists of the following components in percentage by weight: 45-70% of soft magnetic ferrite, 8-15% of solvent type resin, 20-40% of high-boiling point solvent and 2-5% of auxiliary. The fineness of the prepared soft magnetic ink is less than 15 microns, the viscosity is 10-60Pa.s, the drying speed is 80-120s (the drying temperature is 120 DEG C), and the adhesion is greater than or equal to 4B. The soft magnetic ferrite printing ink provided by the invention is applied to a 13.56MHz RFID (radio frequency identification) tag printed antenna, and the inductance quantity of a coil of the RFID tag antenna can be increased by 2-10% so as to reduce the size of the RFID tag antenna.

Description

A kind of soft magnetic ferrite printing ink and its application

technical field

The invention relates to a soft ferrite printing ink and its application, in particular to a soft ferrite printing ink and its application on a 13.56MHz RFID tag printing antenna, belonging to the fields of printing ink and printed electronics.

Background technique

With the rapid development of printed electronics technology, the development of functional inks for printed electronics is extremely urgent. At present, conductive ink, the key material for printed electronics, has attracted much attention, but other functional inks have been developed relatively little. Soft magnetic ferrite is cheap and has excellent performance. It is prepared into functional ink, which can be used in RFID tags (RFID is the abbreviation of Radio Frequency Identification, translated into electronic tags in Chinese, also known as radio frequency identification technology), sensors, information storage, sewage treatment It has great application value in other fields. At present, electronic tag coils are mainly produced by etching, winding and printing. Among them, the cost of manufacturing electronic tag coils by etching is high, and there is a serious problem of environmental pollution. The electronic label coil is produced by printing, which has the characteristics of less investment in equipment, high production efficiency, low production cost, flexible application of antenna structure, and less environmental protection problems.

For the electronic tag with a working frequency of 13.56MHz, when the distributed inductance of the tag antenna coil and the equivalent capacitance of the module input form a resonant circuit, the tag can absorb the maximum energy and the tag can work reliably. The inductance coil is an important part of the resonant circuit inside the electronic tag. The inductance value and quality factor Q value at the corresponding operating frequency are the key physical quantities to judge the quality of the coil. The tag works around 13.56MHz, and its inductance value is usually 2-6μH. The inductance value is related to the number of turns, size, shape and medium of the coil. The Q value of the coil is related to the DC resistance of the wire, the dielectric loss of the skeleton, the loss caused by the shield or iron core, and the influence of high-frequency skin effect. Using magnetic core coils, multi-strand thick coils can increase the Q value of the coils. Adding a ferrite core to the air-core coil can increase the inductance value of the coil.

At present, the cost and miniaturization of RFID tags are problems that limit their application and promotion. The difficulty of the 13.56MHz tag antenna coil is that the inductance value is small, and if the size of the 13.56MHz RFID tag antenna is further reduced, the inductance value will be more difficult to meet the use requirements. The inductance value is different when the number of turns of the coil is different or whether there is a magnetic core or not. The more turns of the coil, the larger the inductance value, but at the same time, it also limits the size of the label and cannot be further reduced.

Therefore, providing a kind of soft magnetic ferrite printing ink and its application in 13.56MHz RFID label printing antenna helps to solve the technical problems in this technical field.

Contents of the invention

The main purpose of the present invention is to provide a soft ferrite printing ink according to the development needs of the printed electronics field.

The soft magnetic ferrite printing ink of the present invention is made up of the following components by weight percentage:

A preferred technical solution is characterized in that: the soft magnetic ferrite is nano-sized γ-Fe ₂ O ₃ or micron-sized manganese zinc ferrite.

A preferred technical solution is characterized in that: the solvent-based resin is epoxy resin, acrylic resin or polyurethane.

A preferred technical scheme is characterized in that: the high boiling point solvent is HDBE (mixed dibasic acid ester, dibasic acid ester), DBE (mixed dibasic acid ester, dibasic acid ester), glycerol, ethyl acetate One or more composite solvents of esters, diethylene glycol butyl ether and cyclohexanone.

A preferred technical solution is characterized in that: the auxiliary agent is an adhesion promoter and/or a leveling agent.

A preferred technical solution is characterized in that: the adhesion promoter is polyvinylpyrrolidone (PVP) or acetylacetonate titanate chelate (titanium acetylacetonate).

A preferred technical solution is characterized in that: the leveling agent is polyacrylate, polyether siloxane copolymer or silicone surface additive.

The preparation method of the soft magnetic ferrite printing ink of the present invention comprises: taking a certain amount of nanometer or micron soft magnetic ferrite, solvent-based resin, high boiling point solvent and auxiliary agent sequentially according to the formula, after mixing, use a three-roll mill Or ball mill or horizontal sand mill for grinding, after uniform dispersion, the soft ferrite printing ink can be obtained.

The above-mentioned solvent-based resins include epoxy resin, acrylic resin, polyurethane, etc.; high boiling point solvents include HDBE, DBE, diethylene glycol butyl ether, ethyl acetate, glycerol, cyclohexanone, etc. or their composite solvents; additives include Adhesion promoters and/or leveling agents, etc.

Another object of the present invention is to provide an application of the above-mentioned soft ferrite printing ink.

An application of soft magnetic ferrite printing ink, the soft magnetic ferrite printing ink is printed on the front or back of the RFID label printed antenna, which acts as a magnetic core and increases the 13.56MHz RFID label printed antenna coil. The inductance value meets the actual use requirements and is conducive to the miniaturization of RFID tags.

When the number of turns of the coil remains unchanged, the inductance value of the coil will increase when the core is increased. Therefore, the soft ferrite ink is applied to the 13.56MHz RFID tag printing antenna, which acts as a magnetic core and increases the inductance value of the coil, which is conducive to the stable reading of the RFID tag or the size of the RFID tag antenna. further reduced.

Advantages of the present invention:

(1) The fineness of the soft magnetic ink prepared by the present invention is less than 15 μm, the viscosity is 10-60 Pa·s, the drying speed is 80-120 s (drying temperature 120 ° C), and the adhesion is ≥ 4B.

(2) Applying the soft ferrite ink of the present invention as a magnetic core to a 13.56MHz RFID tag printing antenna, the inductance value of the coil is significantly increased (increased by 2-10%), which is conducive to the stable reading of RFID tags, And can further reduce the size of the RFID tag antenna.

The present invention will be further described below through the drawings and specific embodiments, but it does not mean to limit the protection scope of the present invention.

Description of drawings

Fig. 1 is the rheological curve of printing ink 1 prepared with nanoscale γ-Fe ₂ O ₃ in Example 1 of the present invention.

Fig. 2 is a rheological curve of printing ink 2 prepared with micron-sized manganese zinc ferrite in Example 2 of the present invention.

Figure 3 is one of the hysteresis loops of the printing ink 3 printed film prepared in Example 3 of the present invention.

Fig. 4 is the second hysteresis loop of the printing ink 3 printed film prepared in Example 3 of the present invention.

Fig. 5 is the hysteresis loop of the printed film of printing ink 4 prepared in Example 4 of the present invention.

Fig. 6 is an SEM image of the printed film of printing ink 1 prepared in Example 1 of the present invention.

Fig. 7 is an SEM image of the printed film of printing ink 2 prepared in Example 2 of the present invention.

Figure 8-1 is the RFID coil printed with conductive ink, and Figure 8-2 is the ferrite printing ink printed on the surface or back of the RFID coil shown in Figure 8-1. Fig. 8-3 is a schematic diagram of the application of the soft ferrite printing ink of the present invention to the RFID printing coil.

Detailed ways

Example 1:

Weigh it in order according to the formula, mix it, grind it with a three-roll mill, a ball mill or a horizontal sand mill, and disperse evenly to prepare the soft ferrite printing ink 1.

Example 2:

Weigh in sequence according to the formula, mix, grind with a three-roll mill, ball mill or horizontal sand mill, and disperse evenly to prepare soft ferrite printing ink 2.

Example 3

Weigh in order according to the formula, after mixing, grind with a three-roll mill, ball mill or horizontal sand mill, and evenly disperse to prepare soft ferrite printing ink 3.

Example 4

Weigh in order according to the formula, after mixing, grind with a three-roll mill, a ball mill or a horizontal sand mill, and evenly disperse to prepare the soft ferrite printing ink 4.

Example 5

Weigh in order according to the formula, after mixing, grind with a three-roll mill, a ball mill or a horizontal sand mill, and evenly disperse to prepare the soft ferrite printing ink 5.

Example 6

Weigh in order according to the formula, after mixing, grind with a three-roll mill, a ball mill or a horizontal sand mill, and evenly disperse to prepare the soft ferrite printing ink 6.

Performance test and application of soft ferrite printing ink:

1. The soft ferrite printing inks 1-6 prepared in Examples 1-6 were tested, and the performance parameters in Table 1 were obtained. The viscosity is tested with a rheometer at 25°C, the adhesion is tested with a barometer, and the fineness is tested with a scraper fineness meter.

The performance parameter of table 1 embodiment 1-6 soft ferrite printing ink

The fineness of the soft ferrite printing inks 1-6 prepared in the above examples 1-6 are all less than 15 μm, the viscosity is 10-60 Pa·s, the drying speed is 80-120 s (drying temperature 120 ° C), and the adhesion is ≥ 4B.

2. Rheological curve

The rheological curves of ferrite printing inks 1 and 2 prepared in Examples 1 and 2 are shown in Figure 1 and Figure 2, respectively. It shows that the ink of the present invention belongs to shear thinning fluid. When the shear rate is 1 (1/s), the viscosities of the ferrite printing inks in Examples 1 and 2 are 29.3 Pa·s and 42.5 Pa·s, respectively.

3. Hysteresis loop

The soft ferrite printing inks of Examples 3 and 4 were respectively printed on a 100 μm thick pre-coated PET film, and the thickness of the printed film was tested by a surface profiler, and the hysteresis loop of the printed film was tested by a vibrating magnetometer. Example 3 The thickness of the printed film layer of the ferrite printing ink is 7.1 μm and 1.5 μm respectively, and the hysteresis loops are shown in Figure 3 and Figure 4 respectively. Example 4 The thickness of the printed film layer of ferrite printing ink is 2.3 μm, and the hysteresis loop is shown in FIG. 5 .

It can be seen from Figure 3 that the coercive force (Hc) of the soft magnetic ink printing film made of micron manganese zinc ferrite is 39.69G, and the saturation magnetization (Ms) is 7.63emu/cm ³ . It can be seen from Figure 4 that the coercive force (Hc) of the soft magnetic ink printing film made of micron manganese zinc ferrite is 37.45G, and the saturation magnetization (Ms) is 1.89emu/cm ³ . The saturation magnetization of the printed film increases as the thickness of the printed film layer increases. It can be seen from Figure 5 that the coercive force (Hc) of the soft magnetic ink printing film prepared by nanoscale γ-Fe ₂ O ₃ is 58.69G, and the saturation magnetization (Ms) is 0.39emu/cm ³ .

4. Electron microscope scanning

Examples 1 and 2 The scanning electron microscope of the ferrite printing ink printing film is shown in Figure 6 and Figure 7 respectively. It can be seen from Figure 6 that the surface of the printing film is relatively uniform, and the soft ferrite ink prepared by nanometer γFe ₂ O ₃ The particle size distribution is uniform and the particle dispersibility is good. It can be seen from Figure 7 that the surface of the printed film is relatively uniform, and the particle size of the micron manganese zinc ferrite ink pigment is large and the distribution is wide.

5. Application

The prepared soft ferrite printing ink 1 or 2 is applied to the RFID label printing antenna coil by printing, and the specific application method is shown in Figure 8-1, 8-2 and Figure 8-3.

Figure 8-1 is the RFID coil printed with conductive ink, and Figure 8-2 is the ferrite ink printed on the front or back of the RFID coil, and the area can be adjusted according to the size of the coil. Figure 8-3 is a schematic diagram of applying ferrite printing ink to RFID printing coils.

The inductance value is tested by a precision impedance analyzer, and the ferrite printing ink is applied to the coil of the RFID label printed antenna, and the inductance value increases by 2% to 10%. The increase in inductance value is related to the solid content, thickness and area of ferrite printing ink.

Claims (6)

1. a soft magnetic ferrite printing-ink, its weight percent consists of: soft magnetic ferrite 45 ~ 70%; Solvent type resin 8 ~ 15%; High boiling solvent 20 ~ 40%; Auxiliary agent 2 ~ 5%; Described soft magnetic ferrite is nano level γ-Fe ₂o ₃or micron order Mn-Zn ferrite, described solvent type resin is epoxy resin, acrylic resin or urethane, and described high boiling solvent is one or more in HDBE, DBE, glycerol, ethyl acetate, butyl and pimelinketone.

2. soft magnetic ferrite printing-ink according to claim 1, is characterized in that: described auxiliary agent is adhesion promoter and/or flow agent.

3. soft magnetic ferrite printing-ink according to claim 2, is characterized in that: described adhesion promoter is polyvinylpyrrolidone or titanium acetylacetone.

4. soft magnetic ferrite printing-ink according to claim 2, is characterized in that: described flow agent is polyacrylic ester, polyether siloxane copolymer or organosilyl surface auxiliary agent.

5. any one soft magnetic ferrite printing-ink application in RFID label tag printed antenna in claim 1-4.

6. the application of soft magnetic ferrite printing-ink according to claim 5 in RFID label tag printed antenna, it is characterized in that: the front or the back side that soft magnetic ferrite printing-ink are printed on RFID label tag printed antenna, play the effect of magnetic core, increase the inductance value of printed antenna coil.