Conductive non-woven fabric material

Abstract

A conductive non-woven fabric material. The conductive non-woven fabric material contains non-woven fabric and a metal coating, and the non-woven fabric is polyphenylene sulfide non-woven fabric or polyester spunbond non-woven fabric. The conductive non-woven fabric material has the characteristics of high strength retention, excellent temperature resistance and electromagnetic wave shielding performance, and can be applied to the fields of electromagnetic wave shielding and mainboard protection of devices such as motors, cables, capacitors and transformers.

Description

Conductive non-woven materials Technical Field

[0001] The invention relates to a conductive non-woven fabric material. Background Art

[0002] As we all know, electromagnetic wave shielding materials are divided into metal materials and conductive materials. Although metal materials have excellent shielding properties in electromagnetic and electrostatic fields, their large-scale application is limited by disadvantages such as high density, susceptibility to corrosion, and difficulty in processing. Conductive materials are formed by spraying or chemical plating a thin conductive layer on the surface of a resin substrate. However, this thin conductive layer can fall off the substrate under external forces such as collisions, resulting in a decrease in the electromagnetic wave shielding performance of the conductive material.

[0003] For example, Chinese patent CN111432508A discloses a graphene fast heating film and its preparation method. The heating film is made by coating a nanographene slurry on a PI film. During the coating process, due to the different volatilization rates of the solutions coated on the surface and the bottom layer, the coating solution flows from the low surface tension to the high surface tension, resulting in an uneven coating surface and easy falling off of the coating, thereby causing the electromagnetic wave shielding performance of the material to deteriorate.

[0004] To address the problem of poor electromagnetic wave shielding properties of materials, technicians have researched and developed non-woven fabric materials formed by metal coating on polyester non-woven fabrics. For example, Chinese patent CN112703281A discloses a non-woven fabric for electromagnetic wave shielding and an electromagnetic wave shielding material. This electromagnetic wave shielding material is made by applying a metal coating to a polyester wet-laid non-woven fabric. Because the ester bonds in polyester fibers are easily broken at high temperatures, the molecular chains of the polyester fibers are broken, thereby reducing the physical properties of the polyester non-woven fabric. As a result, the strength retention rate of this electromagnetic wave shielding material is low and the shrinkage rate is high, which limits its use in high-temperature environments. Summary of the Invention

[0005] An object of the present invention is to provide a conductive nonwoven fabric material having high strength retention, excellent temperature resistance and electromagnetic wave shielding properties.

[0006] The technical solution of the present invention is as follows: the conductive non-woven fabric material of the present invention contains non-woven fabric and metal plating, and the non-woven fabric is polyphenylene sulfide non-woven fabric or polyester spunbond non-woven fabric.

[0007] The nonwoven fabric is preferably a polyphenylene sulfide paper-based nonwoven fabric or a polyester spunbond nonwoven fabric.

[0008] The thickness of the polyphenylene sulfide paper-based nonwoven fabric or the polyester spunbonded nonwoven fabric is 16 to 100 μm.

[0009] The polyphenylene sulfide papermaking nonwoven fabric is preferably composed of poorly-meltable polyphenylene sulfide short fibers and easily-meltable polyphenylene sulfide short fibers.

[0010] The mass ratio of the poorly-meltable polyphenylene sulfide short fibers to the easily-meltable polyphenylene sulfide short fibers is preferably 10:90 to 90:10.

[0011] The polyester spunbond nonwoven fabric is preferably composed of extended long fibers with a core-sheath structure.

[0012] The outermost layer of the conductive nonwoven material of the present invention preferably comprises a tinned layer.

[0013] The average pore size of the conductive nonwoven fabric material of the present invention is preferably 15 to 40 μm.

[0014] In the conductive nonwoven fabric material of the present invention, the proportion of pores with a pore size distribution of 5 to 80 μm is preferably greater than 98%.

[0015] The conductive nonwoven fabric material of the present invention preferably has a melting enthalpy of 8 to 60 J / g and a melting point of 230 to 400°C.

[0016] The crystallization enthalpy of the conductive nonwoven fabric material of the present invention is preferably 1 J / g or less.

[0017] The beneficial effects of the present invention are: since the metal coating of the present invention is evenly distributed and not easy to peel off, and the non-woven fabric is a polyphenylene sulfide non-woven fabric or a polyester spunbond non-woven fabric, the prepared conductive non-woven fabric material has the characteristics of high strength retention, excellent temperature resistance and electromagnetic wave shielding properties. The conductive non-woven fabric material of the present invention can be used in the fields of electromagnetic wave shielding and motherboard protection of equipment such as motors, cables, capacitors and transformers. DETAILED DESCRIPTION

[0018] The conductive nonwoven fabric material of the present invention comprises a nonwoven fabric and a metal coating. The nonwoven fabric is a polyphenylene sulfide nonwoven fabric or a polyester spunbond nonwoven fabric. The nonwoven fabric is metal-plated in the present invention. The metal is preferably gold, silver, copper, zinc, aluminum, nickel, tin, or alloys thereof, more preferably at least one of gold, silver, copper, aluminum, nickel, and tin. Considering conductivity and manufacturing cost, copper or nickel is further preferred. Metal coating methods include electroplating, hot-dip plating, spraying, chemical plating, vapor deposition, permeation plating, or magnetron sputtering, with chemical plating or magnetron sputtering being more preferred. Specifically, the coating method is as follows: the nonwoven fabric is first coated with nickel by magnetron sputtering or chemical plating, then coated with copper by electroplating or chemical plating, and finally coated with nickel by electroplating, magnetron sputtering, or chemical plating. The first nickel coating layer has high magnetic permeability and low magnetic resistance, providing shielding against magnetic waves; the second copper coating layer has high electrical conductivity, providing shielding against electromagnetic waves; and the third nickel coating layer has antioxidant and corrosion-resistant properties.

[0019] The polyphenylene sulfide nonwoven fabric of the present invention is preferably a polyphenylene sulfide spunlace nonwoven fabric, a polyphenylene sulfide needle-punched nonwoven fabric, a polyphenylene sulfide spunbond nonwoven fabric, or a polyphenylene sulfide papermaking nonwoven fabric. Considering the difficulty in processing low-weight and low-thickness polyphenylene sulfide nonwoven fabrics, polyphenylene sulfide papermaking nonwoven fabrics are more preferred. The nonwoven fabric of the present invention can also be a polyester spunbond nonwoven fabric. Compared to polyester papermaking nonwoven fabrics containing unstretched fibers, the polyester spunbond nonwoven fabric of the present invention, composed of stretched fibers, exhibits higher strength retention and lower shrinkage.

[0020] In the conductive nonwoven fabric of the present invention, the polyphenylene sulfide papermaking nonwoven fabric or polyester spunbond nonwoven fabric has a thickness of 16 to 100 μm. If the thickness is too thin, the nonwoven fabric may be damaged during use due to its low strength. Furthermore, too low a thickness means a low fiber feed rate per unit area, resulting in uneven fiber distribution during web formation. During metallization, a small number of fibers and a reduced fiber surface area reduce the metallization amount, while a large number of fibers and an increased fiber surface area increase the metallization amount, resulting in uneven metallization and electromagnetic shielding effectiveness. If the thickness is too thick, it cannot meet the current demand for miniaturization, thinning, and lightweighting of electronic components, and it also makes it difficult to dissipate the heat generated during circuit operation in a timely manner. Considering the uniformity of the electromagnetic shielding performance of the conductive nonwoven fabric and the thinness of electronic components, the thickness of the conductive nonwoven fabric is more preferably 30 to 80 μm, and even more preferably 40 to 80 μm.

[0021] In the conductive nonwoven fabric material of the present invention, the polyphenylene sulfide papermaking nonwoven fabric is preferably composed of difficult-to-melt polyphenylene sulfide staple fibers and easily-melting polyphenylene sulfide staple fibers. The difficult-to-melt polyphenylene sulfide staple fibers herein refer to staple fibers that are difficult to melt or soften after hot rolling at a temperature of 120-250°C during the nonwoven fabric forming process; and the easily-melting polyphenylene sulfide staple fibers refer to staple fibers that are easily melted or softened after hot rolling at a temperature of 120-250°C during the nonwoven fabric forming process. The onset dissolution temperature of the difficult-to-melt polyphenylene sulfide staple fibers is generally higher than 275°C, while the onset dissolution temperature of the easily-melting polyphenylene sulfide staple fibers is generally lower than 265°C.

[0022] When difficult-to-melt polyphenylene sulfide staple fibers are mixed with easily-meltable polyphenylene sulfide staple fibers, the easily-meltable polyphenylene sulfide staple fibers are hot-rolled and melted, acting as a binder to bond the polyphenylene sulfide staple fibers together, producing a polyphenylene sulfide nonwoven fabric. The mass ratio of difficult-to-melt polyphenylene sulfide staple fibers to easily-meltable polyphenylene sulfide staple fibers is preferably between 10:90 and 90:10. If the mass ratio of easily-meltable polyphenylene sulfide staple fibers is too low, the fused portion contains a low amount of staple fibers, which may not be fully bonded, resulting in an uneven surface and low strength retention. If the mass ratio of easily-meltable polyphenylene sulfide staple fibers is too high, the fused portion contains a high amount of staple fibers, resulting in a film-like feel and potentially low strength retention. Considering the surface uniformity and high strength retention of the conductive nonwoven fabric, the mass ratio of difficult-to-melt polyphenylene sulfide staple fibers to easily-meltable polyphenylene sulfide staple fibers is more preferably between 30:70 and 70:30.

[0023] In the conductive nonwoven material of the present invention, the polyester spunbond nonwoven fabric is preferably composed of elongated fibers with a sheath-core structure. The elongated fibers are stretched and aligned, increasing their strength and elongation, resulting in high fiber strength retention and temperature resistance, thereby producing a conductive nonwoven material with high strength retention and low shrinkage.

[0024] The above-mentioned extended long fibers of the sheath-core structure are extended long polyester fibers. Examples of the polyester fibers include polyethylene terephthalate, polyethylene isophthalate, polypropylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, and polybutylene naphthalate.

[0025] The conductive nonwoven fabric material of the present invention preferably comprises a tinned outermost layer. Tin has advantages such as corrosion resistance, discoloration resistance, non-toxicity, ease of soldering, flexibility, a low melting point, and good ductility. Tinned nonwoven fabric materials can be widely used in electronic components, printed circuit boards, and integrated circuit modules.

[0026] The average pore size of the conductive non-woven fabric material of the present invention is preferably 15 to 40 μm. Since the metal coating layer forms a conductive network through physical contact with the fibers in the non-woven fabric, the fibers that are not in physical contact can form electron tunnel junctions with the help of metal particles, so that the non-woven fabric material has conductivity. If it is too small, the resistance of carriers passing through the electron tunnel junction increases, and the amount of carriers that can move freely in the magnetic field of the material decreases. When the conductive non-woven fabric material undergoes reflection loss, the conductivity decreases, and the electromagnetic shielding performance tends to deteriorate. If it is too large, the contact area between the metal coating layer and the fibers in the non-woven fabric per unit area is small, and the amount of metal coating may be reduced. Considering the electromagnetic wave shielding performance of the conductive non-woven fabric, the average pore size of the conductive non-woven fabric material is more preferably 20 to 30 μm.

[0027] The proportion of pores with a pore size distribution of 5 to 80 μm in the conductive nonwoven material of the present invention is preferably greater than 98%. If this proportion is too small, it indicates that the pore size distribution of the conductive nonwoven material is uneven. When electromagnetic waves enter the conductive nonwoven material, some of the electromagnetic waves cannot pass through the pores with too small a diameter and are reflected back, resulting in a decrease in the absorption effect. Other electromagnetic waves directly penetrate to the outside, failing to realize the advantage of electromagnetic wave absorption. Considering the absorption properties of the conductive nonwoven material, the proportion of pores with a pore size distribution of 5 to 80 μm in the conductive nonwoven material is more preferably greater than 99%.

[0028] The conductive nonwoven material of the present invention preferably has a melting enthalpy of 8 to 60 J / g and a melting point of 230 to 400°C. The melting enthalpy refers to the energy required for the nonwoven material to transform from a solid state to a liquid state. The melting enthalpy of the nonwoven material is directly measured by DSC. The melting enthalpy of the nonwoven material is proportional to the crystallinity; a higher melting enthalpy indicates a higher crystallinity. If the melting enthalpy is too low, the nonwoven material has low crystallinity, meaning the crystalline regions are small and there are more amorphous regions between the crystalline regions. The large number of amorphous regions means that the molecular chains are irregular and loosely arranged, the intermolecular forces are weak, and the molecular chains are easily moved. In this case, the strength of the nonwoven material decreases with the increase of amorphous regions, and the nonwoven material may break and its electromagnetic shielding performance will decline. If the melting enthalpy is too high, the nonwoven material has high crystallinity, the molecular chains are too tightly arranged, the gaps between the nonwoven material are reduced, the intermolecular forces are increased, and the chain segments become difficult to move. The nonwoven material tends to have lower elongation at break and impact toughness, and the nonwoven material becomes hard and brittle. Considering the electromagnetic shielding properties and strength of the conductive nonwoven material, the melting enthalpy of the nonwoven material is preferably 20-60 J / g.

[0029] The melting point of the conductive nonwoven material of the present invention is 230-400°C. The melting point refers to the temperature at which the nonwoven material transitions (melts) from a solid state to a liquid state. The higher the melting point of the nonwoven material, the higher its thermal stability and the more difficult it is to decompose. If the melting point is too low, the nonwoven material has poor heat resistance; if the melting point is too high, the fibers are difficult to fuse, and the strength retention of the nonwoven material is low. Considering the heat resistance and strength retention of the nonwoven material, the melting point of the nonwoven material is preferably between 240-280°C.

[0030] The crystallization enthalpy of the conductive nonwoven material of the present invention is preferably 1.0 J / g or less, more preferably 0.5 J / g or less. The crystallization enthalpy of a conductive nonwoven material refers to the heat released per unit mass when a substance transforms from a molten state to a crystalline state. A lower crystallization enthalpy indicates a higher degree of crystallization of the conductive nonwoven material, more complete crystallization, higher strength retention, and lower thermal shrinkage.

[0031] The conductive nonwoven fabric of the present invention preferably has a strength retention rate of 80% or higher after treatment at 260°C for 10 minutes. A lower strength retention rate indicates that the conductive nonwoven fabric may crack after prolonged use in a high-temperature environment, resulting in a decrease in electromagnetic shielding performance. Considering the electromagnetic shielding effectiveness and mechanical stability of the conductive nonwoven fabric, a strength retention rate of 85% or higher is more preferred.

[0032] The air permeability of the conductive nonwoven material of the present invention is preferably 1 to 100 cm 3 / cm 2 / s. If it is too small, the heat generated by the circuit cannot be dissipated in time, which has a great impact on the overall performance of the electronic device; if it is too large, it means that the pores between the fibers are large, the fiber content per unit area is small, and the metal content plated on the fiber surface is reduced, resulting in poor electromagnetic wave shielding effect of the conductive non-woven fabric material. Considering the high temperature use environment and electromagnetic wave shielding performance of the conductive non-woven fabric material, the air permeability is more preferably 10-80cm 3 / cm 2 / s.

[0033] The surface resistance of the conductive nonwoven fabric of the present invention is preferably 0.01 to 0.10 Ω. The surface resistance of a material is negatively correlated with its conductivity; that is, the lower the surface resistance, the higher the conductivity. If the surface resistance is too low, a dense conductive layer forms on the surface of the nonwoven fabric, reducing the material's air permeability and making it difficult for heat generated during circuit operation to dissipate. If the surface resistance is too high, the conductive layer forms more sparsely, and the electromagnetic shielding properties of the conductive nonwoven fabric tend to deteriorate. Considering the electromagnetic shielding properties of the conductive nonwoven fabric, the surface resistance is more preferably 0.02 to 0.08 Ω.

[0034] The method for preparing the conductive nonwoven material of the present invention preferably comprises the following steps:

[0035] (1) Preparation of polyphenylene sulfide non-woven fabric: polyphenylene sulfide fibers are directly web-formed, dry-laid, or wet-laid through a polymer to obtain a fiber web; the obtained fiber web is hot-rolled and melted to obtain a polyphenylene sulfide non-woven fabric;

[0036] Preparation of polyester spunbond nonwoven fabric: High and low melting point polyester filaments are dried at 50-120°C respectively, extruded through a screw extruder, sprayed through a spinneret, separated by an electrostatic separator to obtain a fiber web, and then hot-rolled to obtain polyester spunbond nonwoven fabric;

[0037] (2) Preparation of a conductive non-woven fabric material: The non-woven fabric prepared in step (1) is first coated with nickel by magnetron sputtering or chemical plating, then coated with copper by electroplating or chemical plating, and finally coated with nickel by electroplating or magnetron sputtering or chemical plating to finally prepare a conductive non-woven fabric material.

[0038] In step (1), the fiber fineness is preferably 0.5 to 15 dtex. If it is too small, during the combing process, the needle teeth will not easily grasp the fine fibers, resulting in a large amount of flying flowers. Moreover, these fine fibers are not fully combed, and the resulting fiber web is uneven. If it is too large, the pores between the fibers in the non-woven fabric are large, and electromagnetic waves can easily be projected from the surface of the conductive non-woven fabric to the back surface, resulting in a decrease in its electromagnetic wave shielding performance. Considering the uniformity and electromagnetic wave shielding performance of the conductive non-woven fabric, the fiber fineness is more preferably 0.9 to 1.5 dtex.

[0039] In step (2), magnetron sputtering is a process in which ions bombard the surface of the target material to generate heat, and the surface of the target material partially dissolves to form steam. Under the action of the magnetic field, these steams move toward the substrate and condense on the surface of the substrate to form a uniform and dense film. Electroplating is a simple electrochemical process. In the environment of an electrolytic cell, a dense metal layer is formed on the surface of the original substrate. The metal layer has excellent surface smoothness and uniformity. Chemical plating is a self-catalytic plating. According to the principle of redox reaction, the metal ions are reduced to metals in a solution containing metal ions using a reinforcing reducing agent, and then deposited on the surface of various materials to form a dense and uniform metal layer. Considering the degree of peeling of the metal coating, it is more preferred to first form a nickel coating layer on the non-woven fabric by magnetron sputtering, then form a copper coating layer by electroplating, and finally form a nickel coating layer by electroplating.

[0040] In step (2), the metal coating process is single-sided coating or double-sided coating.

[0041] In step (2), the long-term heat-resistant temperature of the conductive non-woven fabric material is preferably above 160°C. Since the actual processing temperature of the conductive non-woven fabric material is 230°C and the use temperature is above 160°C, this long-term heat-resistant temperature value can meet the requirements for use in high-temperature environments.

[0042] The present invention is described in more detail by way of examples. The testing methods for the various physical properties of the conductive non-woven fabric material of the present invention are as follows.

[0043] [Mass ratio of difficult-to-melt fibers to easy-to-melt fibers in conductive nonwoven fabrics]

[0044] Scanning electron microscopy (SEM) analysis of a cross-section of the conductive nonwoven material revealed that the morphology of the non-meltable fibers was identical to that of the standard fibers, while the readily meltable fibers exhibited fusion bonding. A 1 cm long and 1 cm wide section of the conductive nonwoven material was photographed with the SEM at 50x magnification. The equipment automatically calculated the area S1 of the standard fiber portion within a viewing angle and the area S2 of the fusion bonded portion. The area ratio of the non-meltable fibers to the readily meltable fibers, S1 / S2, was then calculated as the mass ratio of the non-meltable fibers to the readily meltable fibers.

[0045]

thickness

[0046] The test was conducted according to GB / T 24218.2-2009. The test pressure was 0.5±0.01kPa and the pressure foot area was φ50mm±1mm. 20 locations on the conductive nonwoven material were randomly selected for measurement, and the average value was calculated.

[0047]

Average pore size

[0048] Conductive nonwoven fabric was cut into 1.5 cm diameter circles and soaked in a surfactant (Poretech Instrument Galwet 15.9 dynes / cm) for 30 minutes. The sample was then placed in the test slot of a capillary flow porosity tester (model CFP-1100AX). After tightening the slot lid, the test was performed. The average pore size was directly calculated from the test results. The final result was the average of three measurements.

[0049] [The proportion of pores with a pore size distribution of 5 to 80 μm in the conductive non-woven fabric material]

[0050] The testing method for pores with a pore size distribution of 5-80 μm is the same as the average pore size test described above. The test results are directly converted into the distribution of the proportion (%) of each pore size (μm) in the entire conductive nonwoven material. The percentage of pores with a pore size distribution of 5-80 μm in the conductive nonwoven material is added together to obtain the distribution. Three measurements are performed, and the final result is the average of these three measurements.

[0051]

Melting enthalpy of conductive non-woven fabric materials

[0052] A 5 mg sample was weighed and placed in a crucible for analysis using a differential scanning calorimeter (DSC, TA Instruments, USA, Model: Q100). The measurement conditions were: heating from 30°C to 450°C under nitrogen at a rate of 16°C / min, followed by quenching with liquid nitrogen. The temperature was then again increased from 30°C to 450°C under nitrogen at a rate of 16°C / min, and finally decreased from 450°C to 30°C at a rate of 16°C / min. Three curves were obtained, and the melting enthalpy at the melting point during the first heating period was recorded as the melting enthalpy of the conductive nonwoven fabric.

[0053]

Melting point of conductive non-woven fabric material

[0054] The same test method as the melting enthalpy value of the conductive non-woven fabric material is used to record the melting point when the temperature is first increased, which is the melting point of the conductive non-woven fabric material.

[0055]

Crystallization enthalpy of conductive non-woven fabric materials

[0056] The same test method as the melting enthalpy of the conductive non-woven fabric material is used to record the crystallization enthalpy value at the first temperature increase, which is the crystallization enthalpy of the conductive non-woven fabric material.

[0057]

Fiber fineness

[0058] The surface of the conductive nonwoven material was tested using a scanning electron microscope (SEM). 20 points were randomly selected for sample preparation and testing. Each point was tested at a magnification of 600 times. The diameters of the structural fibers in the sample were randomly marked. At least 10 fiber diameters were marked at each point. A total of at least 200 fiber diameters were marked and the average value was taken. The fiber fineness was calculated as follows:

[0059] D: fiber fineness, unit is dtex;

[0060] ρ: fiber density, in g / cm 3 ;

[0061] π: pi;

[0062] R: fiber diameter, in μm;

[0063] W: The standard moisture regain of the fiber, in %.

[0064]

Strength retention rate

[0065] The test was conducted according to GB / T 24218.3-2010 (average value of N = 5). The conductive nonwoven material had an effective width of 50 mm ± 1 mm, a sample gauge length of 200 mm ± 1 mm (sampling length 300 mm), and a test speed of 100 ± 10 mm / min. The strength of the untreated conductive nonwoven material and the treated product at 260°C for 10 minutes were tested. The strength retention of the conductive nonwoven fabric was calculated as follows:

[0066] τ: strength retention rate, in %;

[0067] ε1: Strength of conductive non-woven fabric after treatment at 260℃×10min, unit is N / 5cm;

[0068] ε0: Strength of untreated conductive nonwoven fabric, unit is N / 5cm.

[0069]

Breathability

[0070] The air permeability tester TEXTEST FX3300 was used for the test, with a test area of ​​38 cm 2 , the test pressure difference is 125Pa. Press the non-woven material sample onto the test head, and the instrument generates a continuous airflow through the non-woven material, creating a certain pressure difference on both sides of the sample. The system will automatically calculate the volume of air flowing through the material per unit area per unit time, which is the air permeability of the non-woven material.

[0071]

Surface resistance value

[0072] The surface resistance of conductive nonwoven materials is measured according to the ASTM F390-2011 "Standard Test Method for Sheet Resistance of Conductive Nonwoven Fabrics by Collinear Four-Probe Method".

[0073]

Heat shrinkage rate

[0074] Take a conductive non-woven fabric material with a length of 20 cm and a width of 20 cm, connect the midpoints in the length and width directions respectively, take three samples, test the lateral distance respectively, calculate the average value of the three data (L0), and then place it horizontally in a constant temperature box at 200°C. After 1 hour, take it out and cool it to room temperature. Test the lateral distance of the three samples and calculate the average value (L1). The calculation formula for the thermal shrinkage rate of the conductive non-woven fabric material is as follows: Thermal shrinkage rate (%) = (L0-L1) / L0×100%.

[0075]

Uniformity of metal coating

[0076] The uniformity of the metal plating film on the conductive nonwoven fabric was visually evaluated using a 3-point scale: 0 (good), △ (fair), and × (poor).

[0077] Example 1

[0078] (1) Preparation of fiber web: 100 wt% polyester fibers are directly webbed through a polymer to prepare a polyester fiber web;

[0079] (2) Preparation of non-woven fabric: The polyester fiber web prepared in step (1) is subjected to hot rolling processing and melted to obtain a polyester spunbond non-woven fabric;

[0080] (3) Preparation of a Conductive Nonwoven Fabric: One side of the polyester spunbond nonwoven fabric prepared in step (2) was first coated with nickel by magnetron sputtering, then coated with copper by electroplating, and finally coated with nickel by electroplating to produce the conductive nonwoven fabric of the present invention. The physical properties of the conductive nonwoven fabric are shown in Table 1.

[0081] Example 2

[0082] (1) Preparation of fiber web: 70 wt% of infusible polyphenylene sulfide staple fibers and 30 wt% of easily fusible polyphenylene sulfide staple fibers were mixed and then formed into a web by dry lamination to prepare a polyphenylene sulfide fiber web;

[0083] (2) Preparation of non-woven fabric: The polyphenylene sulfide fiber web prepared in step (1) is sprayed onto a multi-layer fiber web by a high-pressure fine water stream, and after being spunlace treated, it is dried to prepare a polyphenylene sulfide spunlace non-woven fabric;

[0084] (3) The preparation process of the conductive nonwoven fabric material is the same as that of Example 1. The physical properties of the conductive nonwoven fabric material of the present invention are shown in Table 1.

[0085] Example 3

[0086] (1) Preparation of fiber web: 70 wt% of infusible polyphenylene sulfide staple fibers and 30 wt% of easily fusible polyphenylene sulfide staple fibers were mixed and then wet-laid to prepare a polyphenylene sulfide fiber web;

[0087] (2) Preparation of non-woven fabric: The polyphenylene sulfide fiber web prepared in step (1) is subjected to hot rolling processing and melted to obtain a polyphenylene sulfide papermaking non-woven fabric;

[0088] (3) The preparation process of the conductive nonwoven fabric material is the same as that of Example 1. The physical properties of the conductive nonwoven fabric material of the present invention are shown in Table 1.

[0089] Examples 4 to 10 and 12

[0090] The preparation process is the same as that of Example 3. The specific formula and physical properties are shown in Table 1 and Table 2.

[0091] Example 11

[0092] (1) The preparation process of fiber web and non-woven fabric is the same as that in step 3.

[0093] (2) Preparation of a Conductive Nonwoven Fabric: Both sides of the prepared polyphenylene sulfide papermaking nonwoven fabric were first coated with nickel by magnetron sputtering, then coated with copper by electroplating, then coated with nickel by electroplating, and finally coated with tin by electroplating to produce the conductive nonwoven fabric of the present invention. The physical properties of the conductive nonwoven fabric are shown in Table 2.

[0094] Example 13

[0095] (1) Preparation of fiber web: 30 wt% of stretched polyester long fibers with a skin structure and 70 wt% of stretched polyester long fibers with a core structure were directly formed into a web by polymer to prepare a polyester fiber web;

[0096] (2) Preparation of non-woven fabric: The polyester fiber web prepared in step (1) is subjected to hot rolling processing and melted to obtain a polyester spunbond non-woven fabric;

[0097] (3) Preparation of a Conductive Nonwoven Fabric: One side of the polyester spunbond nonwoven fabric prepared in step (2) was first coated with nickel by magnetron sputtering, then coated with copper by electroplating, and finally coated with nickel by electroplating to produce the conductive nonwoven fabric of the present invention. The physical properties of the conductive nonwoven fabric are shown in Table 2.

[0098] Comparative Example 1

[0099] (1) Preparation of fiber web: 70 wt% of infusible polyphenylene sulfide staple fibers and 30 wt% of easily fusible polyphenylene sulfide staple fibers were mixed and then wet-laid to prepare a polyphenylene sulfide fiber web;

[0100] (2) Preparation of non-woven fabric: The polyphenylene sulfide fiber web prepared in step (1) was hot-rolled and melted to obtain polyphenylene sulfide papermaking non-woven fabric. The physical properties of the non-woven fabric material are shown in Table 3.

[0101] Comparative Example 2

[0102] (1) Preparation of a fiber web: 70 wt% of difficult-to-melt polyester staple fibers and 30 wt% of easily-melt polyester staple fibers were mixed and then wet-laid to prepare a polyester fiber web;

[0103] (2) Preparation of non-woven fabric: The polyester fiber web prepared in step (1) is subjected to hot rolling processing and melted to obtain a polyester papermaking non-woven fabric;

[0104] (3) Preparation of a Conductive Nonwoven Fabric: One side of the polyester papermaking nonwoven fabric prepared in step (2) was first coated with nickel by magnetron sputtering, then coated with copper by electroplating, and finally coated with nickel by electroplating to produce a conductive nonwoven fabric. The physical properties of the conductive nonwoven fabric are shown in Table 3.

[0105] Table 1

[0106] Table 2

[0107] Table 3

[0108] According to the above table,

[0109] (1) It can be seen from Example 2 and Example 3 that, under the same conditions, the non-woven fabric in the former is a polyphenylene sulfide spunlace non-woven fabric, and the non-woven fabric in the latter is a polyphenylene sulfide papermaking non-woven fabric. Compared with the former, the conductive non-woven fabric material obtained by the latter has a moderate thickness, low surface resistance, and good surface uniformity, that is, it has good conductivity and good electromagnetic wave shielding properties.

[0110] (2) It can be seen from Example 3 and Example 4 that, under the same conditions, the mass ratio of the difficult-to-melt polyphenylene sulfide staple fibers to the easy-to-melt polyphenylene sulfide staple fibers in the former is within a more preferred range. Compared with the latter, the conductive non-woven fabric material obtained by the former has a high strength retention rate, low surface resistance, and good surface uniformity, that is, it has good conductivity and good electromagnetic wave shielding properties.

[0111] (3) It can be seen from Example 3 and Example 5 that, under the same conditions, the amount of the difficult-to-melt polyphenylene sulfide staple fibers in the latter is slightly lower, and the strength retention rate of the conductive non-woven fabric material obtained in the latter is slightly lower than that in the former.

[0112] (4) It can be seen from Example 3 and Example 6 that, under the same conditions, the crystallization enthalpy value of the conductive non-woven fabric material in the former is within a more preferred range, and compared with the latter, the thermal shrinkage rate of the conductive non-woven fabric material in the former is lower.

[0113] (5) It can be seen from Example 3 and Example 7 that, under the same conditions, the melting enthalpy value of the conductive non-woven fabric material in the former is within a more preferred range. Compared with the latter, the conductive non-woven fabric material in the former has a higher strength retention rate and a lower thermal shrinkage rate.

[0114] (6) It can be seen from Example 3 and Example 8 that, under the same conditions, the thickness of the conductive non-woven fabric material in the former is within a more preferred range. Compared with the latter, the surface resistance of the conductive non-woven fabric material in the former is lower, that is, its conductivity is better.

[0115] (7) It can be seen from Example 3 and Example 9 that, under the same conditions, the fineness of the polyphenylene sulfide fiber in the former is within a more preferred range, and the strength retention rate of the conductive non-woven fabric material obtained in the former is higher than that in the latter.

[0116] (8) It can be seen from Example 3 and Example 10 that, under the same conditions, the thickness of the conductive non-woven fabric material in the latter is slightly lower, and compared with the former, the strength retention rate of the conductive non-woven fabric material in the latter is lower.

[0117] (9) It can be seen from Example 3 and Example 11 that, under the same conditions, the non-woven fabric in the latter is first nickel-coated on both sides by magnetron sputtering, then copper-coated by electroplating, then nickel-coated by electroplating, and finally tin-coated by electroplating. Compared with the former, the tin-plated layer of the latter has excellent corrosion resistance and solderability, low surface resistance, that is, good conductivity and good electromagnetic wave shielding properties.

[0118] (10) It can be seen from Example 3 and Example 12 that, under the same conditions, the thickness of the conductive non-woven fabric material in the latter is slightly lower, and compared with the former, the strength retention rate of the conductive non-woven fabric material in the latter is slightly lower.

[0119] (11) It can be seen from Example 1 and Example 13 that, under the same conditions, the polyester spunbond nonwoven fabric in the latter is composed of extended long fibers with a skin-core structure. Compared with the former, the strength retention rate of the conductive nonwoven fabric material obtained in the latter is high.

[0120] (12) It can be seen from Example 3 and Comparative Example 1 that, under the same conditions, the non-woven fabric material in the latter has not been subjected to metal plating treatment. Compared with the former, the non-woven fabric in the latter has no conductivity, that is, it has no electromagnetic wave shielding property.

[0121] (13) It can be seen from Example 3 and Comparative Example 2 that under the same conditions, the conductive non-woven fabric in the latter is a polyester paper non-woven fabric. Compared with the former, the strength retention rate of the conductive non-woven fabric material in the latter is low and the thermal shrinkage rate is high.

Claims

1. Conductive non-woven fabric material, characterized by: The conductive non-woven fabric material contains non-woven fabric and metal plating, and the non-woven fabric is polyphenylene sulfide non-woven fabric or polyester spunbond non-woven fabric.

2. The conductive nonwoven material according to claim 1, wherein: The non-woven fabric is polyphenylene sulfide papermaking non-woven fabric or polyester spunbond non-woven fabric.

3. The conductive nonwoven material according to claim 2, wherein: The thickness of the polyphenylene sulfide papermaking non-woven fabric or the polyester spunbonded non-woven fabric is 16 to 100 μm.

4. The conductive nonwoven material according to claim 2, wherein: The polyphenylene sulfide papermaking nonwoven fabric is composed of difficult-to-melt polyphenylene sulfide short fibers and easy-to-melt polyphenylene sulfide short fibers.

5. The conductive nonwoven material according to claim 4, characterized in that: The mass ratio of the difficult-to-melt polyphenylene sulfide staple fibers to the easily-melt polyphenylene sulfide staple fibers is 10:90 to 90:

10.

6. The conductive nonwoven material according to claim 1, wherein: The polyester spunbond nonwoven fabric is composed of extended long fibers with a sheath-core structure.

7. The conductive nonwoven material according to claim 1, wherein: The outermost layer of the conductive non-woven fabric material comprises a tinned layer.

8. The conductive nonwoven material according to claim 1, wherein: The average pore size of the conductive non-woven fabric material is 15 to 40 μm.

9. The conductive nonwoven material according to claim 1 or 8, characterized in that: The proportion of pores with a pore size distribution of 5 to 80 μm in the conductive non-woven fabric material is more than 98%.

10. The conductive nonwoven material according to claim 1, wherein: The conductive non-woven fabric material has a melting enthalpy of 8 to 60 J / g and a melting point of 230 to 400°C.

11. The conductive nonwoven material according to claim 1, wherein: The crystallization enthalpy of the conductive non-woven fabric material is less than 1.0 J / g.

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