An electronic carrier paper for effective static control and its preparation method

Abstract

This invention belongs to the field of electronic carrier paper preparation technology, specifically relating to an electronic carrier paper and its preparation method for effectively controlling static electricity. The paper comprises a bottom layer, a core layer, a top layer, and a surface sizing layer, which are sequentially stacked and composited. The bottom layer contains 0.06%–0.10% cetyltrimethylammonium bromide (CTAB) by mass; the core layer contains 0.03%–0.06% CTAB by mass of oven-dry pulp; the top layer contains 0.10%–0.15% CTAB by mass of oven-dry pulp; and the surface sizing layer contains 0.08%–0.12% CTAB by mass of oven-dry pulp. By simultaneously adding CTAB in the wet end and surface sizing, a three-dimensional antistatic network with internal gradient conductivity and dense surface discharge is constructed, overcoming the defects of insufficient CTAB content in the surface layer when added only in the wet end and the lack of deep CTAB when added only in the surface sizing.

Description

Technical Field

[0001] This invention belongs to the field of electronic carrier paper preparation technology, specifically relating to an electronic carrier paper and its preparation method that effectively controls static electricity. Background Technology

[0002] The statements herein provide only background information in relation to this invention and do not necessarily constitute prior art.

[0003] Electronic carrier paper, as the core packaging substrate for surface mount components such as multilayer ceramic capacitors (MLCCs), resistors, and inductors, is required to have key properties such as dimensional stability, smooth surface, high internal bonding strength, and controllable antistatic properties.

[0004] During the preparation of electronic carrier paper, static electricity is easily generated by fiber friction during pulp feeding, leading to flocculation, paper breakage, and dust adsorption. Static electricity easily accumulates in the electronic carrier paper during use, which can attract impurities, damage sensitive components, cause packaging jams, and result in abnormal peeling.

[0005] Existing antistatic technologies mainly include the following two types: First, adding antistatic agents only in the wet end of the pulp. This results in significant loss of the antistatic agent with white water, uneven retention, insufficient surface antistatic properties, and inability to cover the antistatic generation during subsequent processes such as paper drying, calendering, and rewinding. Second, adding antistatic agents only to the surface sizing. This method only acts on the shallow layer of the paper, resulting in poor abrasion resistance, temperature and humidity stability, and easy migration and failure with long-term use. Without antistatic protection in the core layer, interlayer charges cannot be quickly discharged, and accumulated static electricity easily attracts impurities, damages sensitive components, and causes packaging jamming and peeling. Abnormalities, etc.: Long-term charge retention will accelerate the migration and failure of antistatic agents, leading to increased surface resistance and prolonged electrostatic decay time, affecting the long-term stability of the electronic carrier paper; the inability to discharge charge will lead to uneven paper formation, large fluctuations in surface resistance, increased risk of paper breakage, flocculation and dust adsorption, and reduced yield and processing stability; moreover, the surface sizing system is incompatible with the wet end antistatic system, and the lack of pre-static suppression measures in the pulp preparation and conveying section leads to uneven paper formation, large fluctuations in surface resistance, and slow electrostatic decay, making it difficult to meet the electrostatic discharge control requirements of high-end electronic carriers.

[0006] In summary, neither of the above two antistatic methods can meet the requirements of static control during the production process of electronic carrier paper and long-term antistatic properties of the finished product. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the purpose of this invention is to provide an electronic carrier paper and its preparation method for effectively controlling static electricity.

[0008] To achieve the above objectives, the present invention is implemented through the following technical solution: In a first aspect, the present invention provides an electronic carrier paper for effectively controlling static electricity, comprising a bottom layer, a core layer, a top layer, and a surface sizing layer sequentially stacked and laminated, wherein... The mass percentage of hexadecyltrimethylammonium bromide (CTAB) in the bottom layer is 0.06%~0.10%; The CTAB content in the core layer is 0.03%~0.06% by mass of the oven-dry pulp; The CTAB content in the surface layer is 0.10%~0.15% by mass of the oven-dry slurry; The CTAB content in the surface sizing layer is 0.08%~0.12% by mass of the oven-dry slurry.

[0009] Secondly, the present invention provides a method for preparing the electronic carrier paper with effective static electricity control, comprising the following steps: CTAB was added to the bottom layer slurry, core layer slurry and top layer slurry in proportion, and cationic starch, PAE wet strength agent, AKD sizing agent and retention and filtration aid were added to each layer of slurry. After removing slag and purifying the three layers of pulp, they are fed into the molding process, and starch is sprayed between the layers to obtain the composite wet paper. After the wet paper is dehydrated and dried once, it is calendered once. Sizing is applied to the paper surface after the first calendering, followed by a second drying and a second calendering to obtain the final product.

[0010] The beneficial effects achieved by one or more embodiments of the present invention described above are as follows: The present invention selects CTAB cationic quaternary ammonium salt antistatic agent, which has excellent compatibility with the papermaking wet end cationic system (starch, PAE, retention aid), high retention rate, low migration, and long-lasting and stable antistatic effect.

[0011] In this invention, the CTAB content in the top layer, bottom layer, and core layer decreases sequentially, which is consistent with the application scenario of electronic carrier tape: the top layer directly contacts the components and the cover tape, and has the highest antistatic strength; the bottom layer needs to make contact, and has the next highest antistatic strength; the core layer mainly provides structural support, and adding an appropriate amount can achieve interlayer charge discharge, avoiding excessive addition that would affect strength and cost.

[0012] By simultaneously adding CTAB during the wet-end and surface sizing processes, a three-dimensional antistatic network with internal gradient conductivity and dense surface dissipation is constructed. This addresses the shortcomings of insufficient CTAB content in the surface layer when added only in the wet end and the lack of deep CTAB when added only in the surface sizing. The resulting electronic carrier tape exhibits uniform surface resistance, rapid electrostatic decay, and effectively improved temperature and humidity resistance and abrasion resistance. Furthermore, the electronic carrier tape experiences no electrostatic interference during production, and the finished product exhibits uniform and durable antistatic properties, good dimensional stability, good internal bond strength, and good heat-sealing and peeling performance, making it suitable for mass production.

[0013] This invention implements full-process electrostatic control during pulp preparation, feeding, forming, drying, calendering, and winding: online charge monitoring, equipment grounding, ion elimination, and concentration and humidity regulation, which suppresses static electricity generation from the source, solves problems such as paper breakage, flocculation, and dust adsorption in production, and improves yield and processing stability. Detailed Implementation

[0014] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0015] In a first aspect, the present invention provides an electronic carrier paper for effectively controlling static electricity, comprising a bottom layer, a core layer, a top layer, and a surface sizing layer sequentially stacked and laminated, wherein... The mass percentage of hexadecyltrimethylammonium bromide (CTAB) in the bottom layer is 0.06%~0.10%; The CTAB content in the core layer is 0.03%~0.06% by mass of the oven-dry pulp; The CTAB content in the surface layer is 0.1% to 0.15% of the oven-dry slurry. The CTAB content in the surface sizing layer is 0.08%~0.12% by mass of the oven-dry slurry.

[0016] The surface layer, which directly contacts electronic components (such as MLCCs, resistors, etc.) and the cover tape, must have the highest antistatic strength to prevent static electricity accumulation from damaging sensitive components or causing packaging jams. As the interface layer that contacts the components, the surface layer has a high CTAB content, which can quickly dissipate surface charge, avoid static electricity adsorption of impurities, and ensure that there is no static interference when peeling it off from the cover tape.

[0017] The bottom layer is a secondary contact layer (such as in contact with conveying equipment), which needs to maintain a certain level of antistatic capability. At the same time, as part of the structural support layer, it balances antistatic performance and cost. The content of the antistatic agent CTAB is lower than that of the surface layer but higher than that of the core layer. This avoids the accumulation of charge in the bottom layer from affecting the overall static control, and also reduces the total amount of CTAB used through gradient design, thereby reducing production costs.

[0018] The core layer primarily provides structural support, and uses an appropriate amount of CTAB to facilitate rapid dissipation of interlayer charge, preventing uneven paper formation or reduced strength caused by charge retention. The core layer accounts for 40%–60% of the base paper's mass. Excessive CTAB addition can affect fiber bonding strength; therefore, only the minimum concentration is needed to meet the interlayer charge conduction requirements, balancing structural stability with antistatic effects.

[0019] The surface sizing layer forms a three-dimensional antistatic network with the wet end layers, solving the defects of insufficient CTAB in the surface layer when only added to the wet end and lack in the deep layer when only surface sizing is added. The CTAB in the sizing layer can form a dense conductive film on the paper surface, improving abrasion resistance and temperature and humidity stability. In synergy with the wet end gradient antistatic system, it ensures uniform surface resistance and accelerates the static electricity decay rate.

[0020] By gradient addition of CTAB to each wet-end layer in synergy with the surface sizing layer, a three-dimensional antistatic system with internal gradient conductivity and dense surface discharge is formed. The CTAB content decreases sequentially in the top, bottom, and core layers, ensuring rapid charge conduction from the surface to the core and preventing localized charge accumulation. The surface sizing layer CTAB forms a dense conductive film on the paper surface, solving the problem of insufficient surface antistatic properties when added only in the wet end. Simultaneously, it synergizes with the wet-end system to improve abrasion resistance and temperature and humidity stability. The core layer CTAB ensures rapid interlayer charge conduction, preventing long-term retention that could lead to antistatic agent migration and failure, and maintaining the stability of surface resistance and electrostatic decay time.

[0021] In some embodiments, the mass ratio of the top layer, core layer and bottom layer is 20~30:40~60:20~30, preferably 23~27:45~55:23~27.

[0022] Preferably, the total basis weight of the electronic carrier paper is 250~900 g / m³. 2 It meets the thickness and stiffness requirements of the electronic carrier paper.

[0023] In some embodiments, the bottom layer, core layer, and top layer further include cationic starch, PAE wet strength agent, AKD sizing agent, and retention and filtration aids, wherein the mass percentage of cationic starch is 1%-4%; the mass percentage of PAE wet strength agent is 2‰-5%; the mass percentage of AKD sizing agent is 5‰-3%; and the mass percentage of retention and filtration aids is 0.1‰-3%.

[0024] Preferably, the retention and filtration aid is cationic polyacrylamide.

[0025] Cationic starch carries a positive charge, which can combine with the negative charge on the fiber surface and CTAB (cationic quaternary ammonium salt) through electrostatic attraction to form a stable fiber-starch-CTAB composite structure. This reduces the loss of CTAB during the wet end flow process and improves its retention rate in the paper sheet. Starch acts as a binder to enhance the bonding force between fibers and provides a uniformly distributed carrier for CTAB, preventing localized aggregation of antistatic agents and ensuring uniform surface resistance.

[0026] PAE enhances the wet strength of paper through cross-linking reactions. Its cationic properties ensure good compatibility with CTAB and do not interfere with CTAB's charge conduction function. Simultaneously, the three-dimensional network structure formed by PAE can immobilize CTAB molecules, reducing their migration and failure during long-term use. PAE promotes the bonding of fibers in each layer, indirectly ensuring unobstructed charge conduction pathways for the core layer CTAB and preventing interlayer charge retention.

[0027] AKD achieves sizing by forming a hydrophobic layer on the fiber surface. Its weakly cationic properties do not conflict with the quaternary ammonium salt groups of CTAB, thus improving the paper's water resistance without affecting the surface conductivity of CTAB. After sizing with AKD, the paper surface is smoother, reducing localized static electricity accumulation caused by surface roughness, which complements the charge dissipation function of CTAB.

[0028] Retention and filtration aids (such as cationic polyacrylamide) bridge CTAB with fibers, fillers, and other particles, significantly improving CTAB retention in a single pass, preventing its loss with white water, and ensuring that the CTAB content in each layer is precisely controlled within the design range. Retention and filtration aids accelerate pulp dewatering, reduce frictional charging of fibers during the flow process, and work with CTAB to suppress static electricity generation during pulp preparation, reducing the risk of paper breaks and flocculation.

[0029] In some embodiments, the surface sizing layer comprises, by weight, the following components: 20-25 parts oxidized starch, 35-40 parts PVA, 20-25 parts vinyl acetate, 12.8-13.8 parts dry strength agent, 0.1-0.2 parts bactericide, 0.5-1 part lubricant, 0.1-0.2 parts defoamer, 0.5-0.6 parts water-resistant agent, and CTAB accounting for 0.08%-0.12% of the surface sizing layer by weight.

[0030] Oxidized starch, as the matrix component of the sizing layer, forms hydrogen bonds or electrostatic adsorption with CTAB (cationic quaternary ammonium salt) through hydroxyl groups on the molecular chain, uniformly anchoring CTAB on the paper surface and preventing local aggregation or migration of antistatic agents. The film-forming properties of starch combined with the conductive properties of CTAB form a composite film with both strength and antistatic properties, improving the surface's anti-friction ability. The hydroxyl groups of PVA molecular chains interact with the quaternary ammonium groups of CTAB to form a continuous and dense conductive film on the paper surface, reducing the interruption of the charge discharge path and lowering the surface resistance; the strong water absorption of PVA can adjust the humidity of the sizing layer, avoid the fluctuation of the conductivity of CTAB caused by changes in ambient temperature and humidity, and ensure that the electrostatic decay time is <1s. Vinyl acetate, as a film-forming aid, can improve the flexibility of the sizing layer, reduce CTAB shedding caused by paper bending or friction, and enhance the durability of the antistatic effect. Its polar groups work synergistically with CTAB to improve the bonding force between the antistatic agent and the fiber surface, preventing CTAB from migrating and failing during long-term use.

[0031] Dry strength agents (such as polyacrylamide) enhance the bonding strength between the sizing layer and the paper base through cross-linking, preventing CTAB from being lost due to interlayer peeling and ensuring the long-term effectiveness of antistatic properties.

[0032] Preferably, the dry strength agent is a polyacrylamide-based dry strength agent; The bactericide is a conventional isothiazine bactericide; The lubricant is a high molecular weight styrene-acrylic polymer; The defoamer is a mineral oil; The water-resistant agent is a high molecular polymer.

[0033] Secondly, the present invention provides a method for preparing the electronic carrier paper with effective static electricity control, comprising the following steps: CTAB was added to the bottom layer slurry, core layer slurry and top layer slurry in proportion, and cationic starch, PAE wet strength agent, AKD sizing agent and retention and filtration aid were added to each layer of slurry. After removing slag and purifying the three layers of pulp, they are fed into the molding process, and starch is sprayed between the layers to obtain the composite wet paper. After the wet paper is dehydrated and dried once, it is calendered once. After calendering, sizing is applied to the paper surface, followed by a second drying and a second calendering to obtain the electronic carrier paper.

[0034] Interlayer spraying of starch enhances bonding strength.

[0035] In some embodiments, during the preparation of electronic carrier paper, the pulp tank, pipes and pumps are grounded, and an online charge monitor is installed in the pulp tank; an ion wind static elimination device is added to the inlet of the pulp pump to reduce fiber frictional charging; the on-grip concentration is controlled at 0.3%~0.7% to reduce the generation of high shear frictional static electricity.

[0036] Preferably, the inner lining of the conveying pipeline is made of an antistatic material.

[0037] Static electricity generated by fiber friction during pulp preparation and feeding can cause fiber flocculation, resulting in uneven paper sheet formation and increasing the risk of paper breaks. Grounding and ionization techniques can reduce electrostatic attraction between fibers, ensuring uniform pulp dispersion and lowering the probability of production interruptions. Static electricity can also cause the paper sheet to attract dust and impurities from the environment, affecting paper surface cleanliness and leading to a decrease in yield. Controlling static electricity generation can prevent dust adhesion and ensure the smoothness of the base paper surface.

[0038] Static electricity buildup leads to uneven local charge distribution on the paper, causing large fluctuations in surface resistance and making it difficult to meet the stringent requirements of electron carriers for static decay time and surface resistivity. Full-process static control ensures uniform distribution of the antistatic agent (CTAB) and maintains stable conductivity.

[0039] Prolonged charge retention accelerates CTAB migration, leading to increased surface resistance and prolonged electrostatic decay time. By suppressing electrostatic generation, the driving effect of charge on CTAB molecules can be reduced, ensuring the long-lasting antistatic effect.

[0040] In some embodiments, the top layer slurry and the bottom layer slurry include bleached softwood pulp and bleached hardwood pulp, and the mass ratio of bleached softwood pulp to bleached hardwood pulp is 20~40:60~80, preferably 25~35:65~75; The core pulp comprises bleached softwood pulp, bleached hardwood pulp, and waste pulp, with a mass ratio of bleached softwood pulp, bleached hardwood pulp, and waste pulp of 10~30:20~40:40~60, preferably 15~25:25~35:45~55.

[0041] The top and bottom layers directly contact the external environment (such as electronic components, cover tapes, and conveyor equipment), and must simultaneously meet the requirements of surface smoothness, strength, and uniformity. Bleached softwood pulp has longer fibers and stronger interlacing ability, providing higher tensile strength and internal bond strength, ensuring that the carrier tape is not easily broken during processing and use. Bleached hardwood pulp has shorter fibers and a high degree of fibrillation after beating, which can fill the fiber gaps, improve the uniformity and smoothness of the paper surface, and reduce the accumulation of local static electricity caused by surface roughness. By adjusting the proportion of softwood pulp, the uniformity contribution of hardwood pulp can be maximized while ensuring strength, adapting to the core requirements of electronic carrier tape for surface smoothness and dimensional stability.

[0042] The core layer accounts for 40% to 60% of the base paper's weight and primarily serves a structural support role. Cost control is crucial while ensuring basic strength. Adding a small amount of bleached softwood pulp provides the necessary skeletal strength for the core layer, preventing insufficient interlayer bonding due to excessively short fibers. Bleached hardwood pulp works synergistically with softwood pulp to optimize fiber interlacing density and enhance the structural stability of the core layer. Waste pulp, utilizing waste paper generated during production, significantly reduces raw material costs. Furthermore, its strong fiber bonding after secondary beating (48-51°SR) compensates for the high cost of pure wood pulp. In addition, it can synergize with an antistatic system (CTAB gradient addition) to prevent interruptions in charge conduction pathways caused by improper fiber ratios.

[0043] The beating degree of different fibers (38~42°SR for softwood pulp, 33~36°SR for hardwood pulp, and 48~51°SR for waste pulp) is matched with the dewatering rate of each layer to ensure uniform paper sheet during flow forming.

[0044] The surface resistivity of the base paper is controlled at 1×10⁻⁶. 7 ~1×10 9Ω, electrostatic decay time <1s, meeting the requirements of ESDS20.20 and EIA-481-F standards.

[0045] Preferably, the freeness of softwood pulp is 38~42°SR, the freeness of hardwood pulp is 33~36°SR, and the freeness of waste pulp is 48~51°SR.

[0046] In some embodiments, the primary drying is a segmented drying process: The first stage of drying is at a temperature of 30-45℃ and a drying time of 80-100 seconds. The second stage of drying is at a temperature of 50~75℃ and a drying time of 80-100 seconds. The third stage of drying is at a temperature of 75~90℃ and a drying time of 80-100 seconds. The fourth stage of drying is at a temperature of 90~100℃ and a drying time of 80-100s. The fifth drying stage has a drying temperature of 100~110℃ and a drying time of 80-100s.

[0047] If wet paper sheets have a high initial moisture content, direct high-temperature drying will cause the surface moisture to evaporate rapidly, forming a hard shell that hinders the escape of internal moisture. This leads to stress concentration within the paper, resulting in cracks or curling. Segmented drying starts at a low temperature, slowly evaporating the surface moisture, and then gradually increasing the temperature to achieve gradient drying from the surface inwards, avoiding structural damage. Fibers exhibit significantly different shrinkage characteristics at different moisture contents. Segmented heating allows the fibers to gradually adapt to changes in moisture content, reducing paper deformation caused by inconsistent local shrinkage and ensuring the dimensional stability of the electronic carrier paper.

[0048] As a cationic antistatic agent, CTAB is prone to migration to the surface at high temperatures due to rapid moisture evaporation, leading to a lack of antistatic agent in the core layer and localized aggregation on the surface. Segmented drying, by controlling the heating rate, allows CTAB to migrate slowly with the moisture and distribute evenly in each layer, ensuring the stability of the gradient antistatic structure from the bottom layer to the core layer to the surface layer.

[0049] CTAB has limited thermal stability. The maximum temperature of the staged drying is controlled below its decomposition temperature. At the same time, the early low-temperature stage is used to fully dehydrate the CTAB and reduce the residence time in the high-temperature stage, which provides some protection against the antistatic agent.

[0050] Preferably, the moisture content of the paper after one drying step is 10-15%; The moisture content of the paper after secondary drying is 7.5-9%.

[0051] After the initial drying, surface sizing is required. The paper needs to retain a certain amount of moisture to ensure even penetration of the sizing solution. 10-15% moisture content allows the fibers to be in a moderately swollen state, which is conducive to the formation of a continuous film layer by the sizing agent on the paper surface and avoids cracking or poor adhesion of the sizing layer due to excessively dry paper.

[0052] Excessive moisture content causes CTAB to migrate to the surface with the moisture, resulting in a lack of antistatic agent in the core layer; insufficient moisture content causes CTAB to fix prematurely during the drying process, preventing even distribution. A moisture content of 10-15% allows CTAB to migrate slowly with the moisture and anchor between fibers, ensuring the stability of the gradient antistatic structure of the bottom layer-core layer-surface layer.

[0053] If the moisture content is too low during the initial drying process, the fibers will shrink drastically due to excessive dehydration, leading to increased internal stress in the paper and making it prone to cracking or curling during subsequent calendering. Conversely, if the moisture content is too high, the paper will be too soft, failing to form a dense surface during calendering, resulting in substandard smoothness and density, and affecting the uniformity of subsequent surface sizing. Excessive moisture content also necessitates the evaporation of more water during the second drying stage, potentially prolonging the drying time or increasing the temperature, leading to accelerated CTAB thermal migration (surface aggregation, core layer loss) and increased surface resistance fluctuations.

[0054] In some embodiments, the linear pressure of primary calendering and secondary calendering is 40~90kN / m, and the hot oil temperature is 140~180℃, which improves the smoothness and density of the paper surface.

[0055] In some embodiments, the method further includes a step of winding the prepared electronic carrier paper, wherein an antistatic bar and a humidity control device are added to the winding section to maintain an ambient relative humidity of 45% to 60% to avoid static electricity accumulation during winding.

[0056] The entire process of finished product cutting and packaging is moisture-controlled and anti-static to ensure stable surface resistance.

[0057] In some embodiments, the application pressure of the adhesive is 30~33 kN / m, the temperature is 40~45℃, the vehicle speed is 100~125 m / min, and the application rate per side is 1.8~2.1 g / m. 2 This achieves a dense antistatic film on the surface, forming a three-dimensional conductive network with the gradient antistatic effect in the wet section.

[0058] The present invention will be further described in detail below with reference to specific embodiments, but the present invention is not limited to the following embodiments.

[0059] Example 1 A method for preparing an electronic carrier paper with effective static electricity control includes the following steps: (1) Pulp preparation: Bleached softwood pulp, bleached hardwood pulp and waste pulp were prepared separately, so that the freeness of bleached softwood pulp was 40°SR, the freeness of bleached hardwood pulp was 35°SR and the freeness of waste pulp was 49°SR. The surface pulp composition is as follows: the mass ratio of bleached softwood pulp to bleached hardwood pulp is 30:70, and 1.5% cationic starch, 1.0% PAE wet strength agent, 1.0% AKD sizing agent, 0.02% retention aid and filtration aid and 0.12% CTAB are added simultaneously according to the oven-dry pulp mass. The bottom layer pulp composition is as follows: the mass ratio of bleached softwood pulp to bleached hardwood pulp is 30:70, and 1.5% cationic starch, 1.0% PAE wet strength agent, 1.0% AKD sizing agent, 0.02% retention aid and filtration aid and 0.08% CTAB are added simultaneously according to the oven-dry pulp mass. The core pulp composition is as follows: the mass ratio of bleached softwood pulp, bleached hardwood pulp and waste pulp is 20:30:50. Simultaneously added are 1.5% cationic starch, 1.0% PAE wet strength agent, 1.0% AKD sizing agent, 0.02% retention aid and filter aid and 0.04% CTAB, which account for 1% of the oven-dry pulp mass.

[0060] Static electricity control during slurry preparation: grounding of the slurry tank, online charge monitoring, elimination of ion wind at the slurry pump inlet, and a net concentration of 0.45%.

[0061] (2) After the three layers of pulp are purified by the deslagging device and pressure screen, they are sent into the three-layer headbox. The headbox is equipped with a turbulence generator and precise control of the lip opening to ensure uniform dispersion of the pulp. The inner lining of the conveying pipe is made of antistatic material, and conductive rollers and grounding devices are added to key sections to eliminate static electricity during the conveying process. The three-layer wet paper web is formed by multi-layer circular wire in the wire section, and starch is sprayed between the layers to enhance the bonding strength. After vacuum dewatering and press dewatering, the pressing moisture is controlled at 42% to obtain wet paper.

[0062] (3) The wet paper web was dried in multiple drying cylinders in stages. The first stage drying temperature was 40℃ and the drying time was 92s; the second stage drying temperature was 65℃ and the drying time was 90s; the third stage drying temperature was 80℃ and the drying time was 90s; the fourth stage drying temperature was 95℃ and the drying time was 88s; the fifth stage drying temperature was 105℃ and the drying time was 90s; the moisture content of the dried paper was 12%.

[0063] (4) After drying, the paper is calendered and finished once with a linear pressure of 60 kN / m and a hot oil temperature of 160°C to improve the smoothness and tightness of the paper surface.

[0064] (5) Prepare the surface sizing solution: 25 parts oxidized starch, 40 parts polyvinyl alcohol, 20 parts vinyl acetate, 13.6 parts polyacrylamide, 0.1 parts isothiazine bactericide, 0.6 parts styrene-acrylic polymer lubricant, 0.1 parts mineral oil defoamer, 0.5 parts polymer water-resistant agent, and 0.1% CTAB (sizing solids content ratio). An immersion-type adhesive applicator was used, with an application pressure of 32 kN / m, a temperature of 40℃, a machine speed of 110 m / min, and an application rate of 1.9 g / m² on one side. 2 This achieves surface antistatic dense film formation, forming a three-dimensional conductive network with the wet-end gradient antistatic effect.

[0065] (6) After sizing, the paper web is dried in the post-drying cylinder to a moisture content of 8.5%, and then calendered and finished with the same parameters as the first calendering to obtain the electronic carrier paper product. The electronic carrier paper product is then wound and packaged. Static elimination rods and humidity control devices are added to the winding section to maintain an ambient relative humidity of 50% to avoid static electricity accumulation during winding. The finished product is slit and packaged with humidity control and anti-static measures throughout the process to ensure stable surface resistance.

[0066] The performance of the prepared electronic carrier paper was tested. The surface resistivity is 5.2 × 10⁻⁶. 8 Ω; electrostatic decay time is 0.6s under constant temperature and humidity conditions of 25℃ and 55%; no electrostatic paper breakage or dust adsorption during production; surface strength ≥18A, interlayer bonding force ≥300J / m 2 The stiffness is ≥25mN·m, and all strengths and adhesive properties meet the standards.

[0067] The product exhibits excellent long-term antistatic stability and resistance to environmental degradation: after 6 months of sealed storage at room temperature, the surface resistivity remains stable at 5.4 × 10⁻⁶. 8 The electrostatic decay time remained stable at 0.61 s; after being placed in a harsh environment of high temperature and high humidity (85℃, 85% relative humidity) for 168 hours, the surface resistivity remained stable at 5.8 × 10⁻⁶. 8 Ω, the electrostatic decay time only fluctuates slightly to 0.66s, the antistatic performance decay is minimal, and the high temperature and humidity resistance is excellent, which can meet the long-term stable use requirements under complex working conditions.

[0068] Example 2 The difference from Example 1 is that: 0.15% CTAB is added to the top layer slurry, 0.10% CTAB is added to the bottom layer slurry, 0.06% CTAB is added to the core layer slurry, and 0.12% CTAB (sizing solids content percentage) is added to the surface sizing liquid; the rest is the same as in Example 1.

[0069] The performance of the prepared electronic carrier paper was tested. The surface resistivity is 2.8 × 10⁻⁶. 8 Ω; electrostatic decay time is 0.4s under constant temperature and humidity conditions of 25℃ and 55%; no electrostatic paper breakage or dust adsorption during production; surface strength ≥18A, interlayer bonding force ≥300J / m 2 The stiffness is ≥25 mN·m, and all strength and sizing properties meet the standards. The product has excellent long-term antistatic stability and resistance to environmental degradation: after 6 months of sealed storage at room temperature, the surface resistivity remains stable at 2.8×10⁻⁶. 8 The electrostatic decay time remained stable at 0.4 s; after being placed in a harsh environment of high temperature and high humidity (85℃, 85% relative humidity) for 168 hours, the surface resistivity remained stable at 3×10 Ω. 8 Ω, the electrostatic decay time only fluctuates slightly to 0.43s, the antistatic performance decay is minimal, and the high temperature and humidity resistance is excellent, which can meet the long-term stable use requirements under complex working conditions.

[0070] Example 3 The difference from Example 1 is that: 0.1% CTAB is added to the top layer slurry, 0.06% CTAB is added to the bottom layer slurry, 0.03% CTAB is added to the core layer slurry, and 0.08% CTAB (sizing solids content percentage) is added to the surface sizing liquid; the rest is the same as in Example 1.

[0071] The performance of the prepared electronic carrier paper was tested. The surface resistivity is 7.3 × 10⁻⁶. 8 Ω; electrostatic decay time is 0.8s under constant temperature and humidity conditions of 25℃ and 55%; no electrostatic paper breakage or dust adsorption during production; surface strength ≥18A, interlayer bonding force ≥300J / m 2 The stiffness is ≥25 mN·m, and all strength and sizing properties meet the standards. The product has excellent long-term antistatic stability and resistance to environmental degradation: after 6 months of sealed storage at room temperature, the surface resistivity remains stable at 7.6×10⁻⁶. 8 The electrostatic decay time remained stable at 0.84 s; after being placed in a harsh environment of high temperature and high humidity (85℃, 85% relative humidity) for 168 hours, the surface resistivity remained stable at 8.1 × 10⁻⁶. 8 Ω, the electrostatic decay time only fluctuates slightly to 0.89s, the antistatic performance decay is minimal, and the high temperature and humidity resistance is excellent, which can meet the long-term stable use requirements under complex working conditions.

[0072] Comparative Example 1 The difference from Example 1 is that 0.08% CTAB was added to the top layer slurry, bottom layer slurry and core layer slurry, but not to the surface sizing liquid. The rest is the same as in Example 1.

[0073] The performance of the prepared electronic carrier paper was tested. The surface resistivity is 6.5 × 10⁻⁶. 9 Ω; the static decay time is 2.3s in a constant temperature and humidity environment of 25℃ and 55% relative humidity; the surface antistatic properties are insufficient, and the tape easily adsorbs impurities.

[0074] Comparative Example 2 The difference from Example 1 is that only 0.15% CTAB (the percentage of sizing solids) is added to the surface sizing solution, and no CTAB is added to the wet end; the rest is the same as in Example 1.

[0075] The performance of the prepared electronic carrier paper was tested. The surface resistivity is 3.1 × 10⁻⁶. 8 Ω; the decay time increases to 3.5s under constant temperature and humidity conditions of 25℃ and 55% relative humidity; poor durability, no charge dissipation between layers, and after being placed in a harsh environment of high temperature and high humidity of 85℃ and 85% relative humidity for 168 hours, the surface resistivity climbs to 2.9×10 10 Ω, the static decay time surged to 11.8s, the antistatic additive only accumulated on the surface of the paper, and was extremely susceptible to moisture and dissolution, and its performance deteriorated significantly after high temperature and high humidity.

[0076] Comparative Example 3 The difference from Example 1 is that in step (1), the cationic starch in each layer of slurry is replaced with ordinary starch, and everything else is the same as in Example 1.

[0077] The performance of the prepared electronic carrier paper was tested. The surface resistivity is 2.7 × 10⁻⁶. 10 Ω; the decay time increased to 11.5s under constant temperature and humidity conditions of 25℃ and 55% relative humidity; poor durability, no charge dissipation between layers, and after being placed in a harsh environment of high temperature and high humidity of 85℃ and 85% relative humidity for 168 hours, the surface resistivity soared to 9.2×10 10 Ω, the electrostatic decay time is significantly extended to 32.0s, and the antistatic performance is significantly reduced.

[0078] Comparative Example 4 The difference from Example 1 is that in step (3), the paper is dried directly at 105°C until the moisture content is 12%, while the rest is the same as in Example 1.

[0079] The performance of the prepared electronic carrier paper was tested. The surface resistivity is 7.3 × 10⁻⁶. 9Ω; the decay time increased to 7.8s under constant temperature and humidity conditions of 25℃ and 55% relative humidity; poor durability, no charge dissipation between layers, and after being placed in a harsh environment of high temperature and high humidity of 85℃ and 85% relative humidity for 168 hours, the surface resistivity soared to 5.1×10 Ω. 11 Ω, electrostatic decay time >25s, performance degradation is obvious after high temperature and high humidity.

[0080] Table 1

[0081] This invention completely solves the technical defects of a single addition method by using a three-layer gradient antistatic method, wet end-surface sizing synergy, and full-process static control during slurry preparation and delivery. The production process is stable and free from static interference, and the surface resistance of the finished product is uniform and controllable, with rapid static decay and long-term stability. At the same time, it maintains the dimensional stability, internal bonding strength, and heat-sealing peel compatibility required by the carrier paper. It is fully compatible with the packaging requirements of high-end surface mount electronic components, and the process is compatible with existing production lines, thus possessing significant industrial value.

[0082] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An electronic carrier paper for effectively controlling static electricity, characterized in that: It includes a composite layer consisting of a base layer, a core layer, a top layer, and a surface adhesive layer, which are stacked sequentially. The mass percentage of hexadecyltrimethylammonium bromide in the bottom layer is 0.06%~0.10%; The CTAB content in the core layer is 0.03%~0.06% by mass of the oven-dry pulp; The CTAB content in the surface layer is 0.1% to 0.15% of the oven-dry slurry. The CTAB content in the surface sizing layer is 0.08%~0.12% by mass of the oven-dry slurry.

2. The electronic carrier paper for effectively controlling static electricity according to claim 1, characterized in that: The mass ratio of the top layer, core layer, and bottom layer is 20~30:40~60:20~30.

3. The electronic carrier paper for effectively controlling static electricity according to claim 1, characterized in that: The bottom layer, core layer, and top layer also include cationic starch, PAE wet strength agent, AKD sizing agent, and retention and filtration aids. The mass percentage of cationic starch is 1%-4%; the mass percentage of PAE wet strength agent is 2‰-5%; the mass percentage of AKD sizing agent is 5‰-3%; and the mass percentage of retention and filtration aids is 0.1‰-3%. Alternatively, the retention and filtration aid is cationic polyacrylamide.

4. The electronic carrier paper for effectively controlling static electricity according to claim 1, characterized in that: The surface sizing layer, by weight, comprises the following components: 20-25 parts oxidized starch, 35-40 parts PVA, 20-25 parts vinyl acetate, 12.8-13.8 parts dry strength agent, 0.1-0.2 parts bactericide, 0.5-1 part lubricant, 0.1-0.2 parts defoamer, 0.5-0.6 parts water-resistant agent, and CTAB accounts for 0.08%-0.12% of the surface sizing layer by weight.

5. The electronic carrier paper for effectively controlling static electricity according to claim 4, characterized in that: The dry strength agent is a polyacrylamide-based dry strength agent; The bactericide is a conventional isothiazine bactericide; The lubricant is a high molecular weight styrene-acrylic polymer; The defoamer is a mineral oil; The water-resistant agent is a high molecular polymer.

6. The method for preparing the electronic carrier paper with effective static electricity control as described in any one of claims 1-5, characterized in that: Includes the following steps: CTAB was added to the bottom layer slurry, core layer slurry and top layer slurry in proportion, and cationic starch, PAE wet strength agent, AKD sizing agent and retention and filtration aid were added to each layer of slurry. After removing slag and purifying the three layers of pulp, they are fed into the molding process, and starch is sprayed between the layers to obtain the composite wet paper. After the wet paper is dehydrated and dried once, it is calendered once. After calendering, sizing is applied to the paper surface, followed by a second drying and a second calendering to obtain the electronic carrier paper.

7. The method for preparing an electronic carrier paper with effective static electricity control according to claim 6, characterized in that: During the preparation of electronic carrier paper, the pulp tank, pipes and pumps are grounded, and an online charge monitor is installed in the pulp tank; an ion wind static elimination device is added to the inlet of the pulp pump; the on-grind concentration is controlled at 0.3%~0.7%; and the inner lining of the conveying pipe is made of antistatic material.

8. The method for preparing electronic carrier paper with effective static electricity control according to claim 6, characterized in that: The surface slurry and the base slurry include bleached softwood pulp and bleached hardwood pulp, with a mass ratio of bleached softwood pulp to bleached hardwood pulp of 20~40:60~80; The core pulp consists of bleached softwood pulp, bleached hardwood pulp, and waste pulp, with a mass ratio of 10~30:20~40:40~60.

9. The method for preparing an electronic carrier paper with effective static electricity control according to claim 6, characterized in that: The primary drying process is a segmented drying process: The first stage of drying is at a temperature of 30-45℃ and a drying time of 80-100 seconds. The second stage of drying is at a temperature of 50~75℃ and a drying time of 80-100 seconds. The third stage of drying is at a temperature of 75~90℃ and a drying time of 80-100 seconds. The fourth stage of drying is at a temperature of 90~100℃ and a drying time of 80-100s. The fifth drying stage has a temperature of 100~110℃ and a drying time of 80-100s; Alternatively, the moisture content of the paper after one drying cycle is 10-15%; the moisture content of the paper after two drying cycles is 7.5-9%.

10. The method for preparing an electronic carrier paper with effective static electricity control according to claim 6, characterized in that: It also includes the step of winding the prepared electronic carrier paper, with an added static elimination bar and humidity control device in the winding section to maintain an ambient relative humidity of 45% to 60%.

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