An anti-skid compression cushion and a preparation method thereof

Abstract

This invention relates to the field of cushioning pad technology, specifically to an anti-slip press-fit cushioning pad and its preparation method. The anti-slip press-fit cushioning pad includes an anti-slip outer fabric disposed on the upper and lower surfaces of an organic fiber woven layer. The anti-slip outer fabric comprises fiberglass cloth and a modified polytetrafluoroethylene (PTFE) layer coated on the surface of the fiberglass cloth. The modified PTFE layer, by weight, comprises: 40-60 parts Teflon emulsion, 15-30 parts modified filler, 1-5 parts water-soluble natural polymer, 0.1-1 parts thickener, and 10-20 parts water. The anti-slip press-fit cushioning pad of this invention can effectively solve the problem of slippage and misalignment between the board and the cushioning pad during the pressing of multilayer printed circuit boards and copper-clad laminates, reducing manual intervention and improving production efficiency and pressing yield.

Description

Technical Field

[0001] This invention relates to the field of cushioning pad technology, specifically to an anti-slip press-fit cushioning pad and its preparation method. Background Technology

[0002] In the manufacturing process of multilayer printed circuit boards and copper-clad laminates, a hot press is typically used for pressing and molding. Because the contact between the hot plate and the steel plate generates impact force, which can severely damage the circuit board and copper plate, a cushioning material needs to be placed between the hot plate and the steel plate during processing to reduce damage to the circuit board and copper plate.

[0003] In the lamination process of multilayer circuit boards, after stacking, a trolley is typically used to transport the stacked boards to the lamination station. Due to efficiency requirements or workshop layout constraints, the trolley often travels at a relatively high speed, or the board surface is quite smooth. When the trolley turns or brakes to a stop, the board and the conventional buffer pad continue to slide forward due to inertia, causing a positional shift. This shift is particularly pronounced when there are many layers. After the shift occurs, operators need to manually correct it before lamination can proceed. This not only increases the frequency of manual intervention and reduces production efficiency but may also lead to an increase in the lamination defect rate, affecting product quality. Summary of the Invention

[0004] The purpose of this invention is to overcome the problems of poor anti-slip properties, easy displacement, insufficient wear resistance, and poor mechanical properties of existing circuit board lamination buffer pads, and to provide an anti-slip lamination buffer pad and its preparation method. This anti-slip lamination buffer pad can effectively solve the problem of sliding and displacement between the board material and the buffer pad during the lamination of multilayer printed circuit boards and copper-clad laminates, reducing manual intervention and improving production efficiency and lamination yield.

[0005] In a first aspect, the present invention provides an anti-slip press-fit cushioning pad, comprising an anti-slip outer fabric disposed on the upper and lower surfaces of an organic fiber woven layer, wherein the anti-slip outer fabric comprises fiberglass cloth and a modified polytetrafluoroethylene layer coated on the surface of the fiberglass cloth; wherein, by weight, the raw materials of the modified polytetrafluoroethylene layer comprise: 40-60 parts of Teflon emulsion, 15-30 parts of modified filler, 1-5 parts of water-soluble natural polymer, 0.1-1 parts of thickener, and 10-20 parts of water.

[0006] As a preferred embodiment of the present invention, the modified polytetrafluoroethylene layer comprises, by weight, 48-53 parts of Teflon emulsion, 22-25 parts of modified filler, 2-2.5 parts of water-soluble natural polymer, 0.5-0.8 parts of thickener, and 14-17 parts of water. This preferred raw material ratio further optimizes the film-forming properties, abrasion resistance, and bonding strength with fiberglass cloth of the modified polytetrafluoroethylene layer, ensuring optimal overall performance of the anti-slip outer fabric.

[0007] Teflon emulsion refers to a stable dispersion of fine polytetrafluoroethylene (PTFE) particles in water. The Teflon emulsion used in this invention is model number Daikin POLYFLON™ PTFE D-610C. The aforementioned Teflon emulsion exhibits excellent dispersion stability and film-forming properties. After coating, it forms a dense, smooth, and wear-resistant surface layer. It also possesses excellent high and low temperature resistance, adapting to operating environments from -200℃ to 260℃, and is suitable for industrial protection and high-temperature buffer protection needs.

[0008] The method for preparing the modified filler includes:

[0009] (1) Dissolve tetrabutyl titanate in anhydrous ethanol to obtain solution A;

[0010] (2) Mix water, glacial acetic acid and anhydrous ethanol to obtain solution B;

[0011] (3) Add solution B dropwise to solution A, and continue the reaction after the addition is complete to obtain titanium dioxide sol precursor;

[0012] (4) Tris powder was added to the titanium dioxide sol precursor to adjust the pH of the system to 8-9, and then dopamine hydrochloride was added to carry out the polymerization reaction. After that, the mixture was centrifuged, washed, dried and ground to obtain the modified filler.

[0013] The modified filler in this invention uses nano-titanium dioxide as the core particle and constructs a TiO2@PDA composite structure by coating the surface of polydopamine (PDA). Compared with commonly used silicon dioxide (SiO2), TiO2 has stronger surface polarity and a higher isoelectric point. Its surface has a higher density of titanium hydroxyl groups (Ti-OH), and under alkaline conditions (pH 8-9), it is more likely to coordinate or hydrogen bond with the catechol groups of dopamine, thereby forming a more uniform and stable PDA coating layer. At the same time, TiO2 itself has a higher dielectric constant and surface energy than SiO2. When it is coated on sodium-treated PTFE fabric, it can more effectively break the low surface energy inert layer of PTFE, increase the interfacial adhesion through polar-polar interactions, and construct a denser micro-rough structure on the fabric surface, significantly improving the coefficient of friction.

[0014] Traditional silane coupling agents (such as KH550 and KH560) or titanate coupling agents modified fillers can only react with specific functional groups and cannot effectively improve the performance of the product. The polydopamine layer in this invention is rich in catechol and amino functional groups, which can form strong chemical bonds and hydrogen bonds with the polar groups such as hydroxyl and carboxyl groups introduced on the surface of sodium-modified PTFE, thereby better achieving the efficient and long-lasting anti-slip effect of the anti-slip compression cushioning pad.

[0015] As a preferred technical solution of the present invention, in step (1), the volume ratio of the tetrabutyl titanate to the anhydrous ethanol is 1:(3~5).

[0016] In step (1), there are no special restrictions on the conditions under which tetrabutyl titanate is dissolved in anhydrous ethanol, as long as it can be completely dissolved in anhydrous ethanol. It is preferable to stir at room temperature for 5 to 10 minutes to ensure that the tetrabutyl titanate is uniformly dispersed, avoid local agglomeration, and lay the foundation for subsequent sol formation.

[0017] As a preferred technical solution of the present invention, in step (2), the volume ratio of water, glacial acetic acid and anhydrous ethanol is 1:1:(20~30).

[0018] In a preferred embodiment of the present invention, the volume ratio of glacial acetic acid to tetrabutyl titanate is 1:(5~10), preferably 1:(6~7). In this invention, glacial acetic acid acts as a catalyst, regulating the hydrolysis rate of tetrabutyl titanate and preventing excessively rapid hydrolysis that could lead to agglomeration of titanium dioxide particles. When the volume ratio of glacial acetic acid to tetrabutyl titanate is controlled at 1:(6~7), the hydrolysis reaction is mild and complete, resulting in the optimal stability of the formed titanium dioxide sol precursor.

[0019] In step (2), there are no special restrictions on the mixing conditions. As long as the water, glacial acetic acid and anhydrous ethanol can be mixed evenly, such as stirring at room temperature for 10 to 20 minutes to ensure that the components are fully integrated and to avoid uneven local concentrations.

[0020] As a preferred technical solution of the present invention, in step (3), the dropping rate of solution B is 0.5~1 mL / min. In the present invention, the slow dropping of solution B can gradually hydrolyze tetrabutyl titanate to form titanium dioxide sol with uniform particle size. If the dropping rate is too fast, it will lead to violent local hydrolysis reaction, producing agglomerated particles, which will affect the dispersibility of the modified filler and the subsequent modification effect.

[0021] As a preferred technical solution of the present invention, in step (3), the reaction conditions include: reacting at room temperature for 1.5 to 3 hours.

[0022] As a preferred embodiment of the present invention, the mass ratio of tetrabutyl titanate to dopamine hydrochloride is 1:(10~20), preferably 1:(12~15, based on titanium dioxide. Dopamine hydrochloride can undergo self-polymerization in the Tris buffer system, forming a polydopamine coating that coats the surface of the titanium dioxide particles. The amino and hydroxyl groups in the polydopamine can form hydrogen bonds with the PTFE particles in the Teflon emulsion and water-soluble natural polymers, thereby enhancing the cohesive strength of the modified polytetrafluoroethylene layer. When the mass ratio is controlled at 1:(12~15), the polydopamine coating thickness is moderate, ensuring both bonding strength and without affecting the dispersibility of the modified filler.

[0023] As a preferred embodiment of the present invention, in step (4), the polymerization reaction conditions include: stirring at room temperature for 12-36 hours under light-protected conditions. The polymerization reaction of polydopamine is sensitive to light; light-protected conditions can prevent the polymerization reaction from being too rapid, which could lead to uneven coating.

[0024] As a preferred technical solution of the present invention, in step (4), the centrifugation conditions include: centrifuging at 8000~10000 r / min for 10~15 minutes. The aforementioned centrifugation conditions can fully separate the modified filler precipitate and remove unreacted dopamine hydrochloride, Tris powder and other impurities in the system.

[0025] As a preferred technical solution of the present invention, in step (4), the washing method includes: washing with deionized water 1 to 3 times and washing with anhydrous ethanol 1 to 3 times in sequence. Deionized water can remove water-soluble impurities, and anhydrous ethanol can remove oil-soluble impurities and residual water. Centrifugation is required after each washing to ensure that impurities are completely removed. The preferred number of washing times is 2 times with deionized water and 2 times with anhydrous ethanol, which takes into account both washing effect and efficiency.

[0026] As a preferred technical solution of the present invention, in step (4), the drying conditions include drying in a vacuum drying oven at 60~80℃ for 12~24 hours.

[0027] In step (4), the grinding method can be a conventional method in the art, as long as the particle size of the solid material is 300~500nm. It is preferred to use a planetary ball mill for grinding, with a grinding time of 2~3 hours, and the grinding media is zirconia balls with a ball-to-material ratio of 10:1 to ensure that the modified filler has a uniform particle size and good dispersibility, and can be uniformly dispersed in the Teflon emulsion to improve the mechanical properties and anti-slip properties of the modified polytetrafluoroethylene layer.

[0028] As an example, the method for preparing the modified filler includes:

[0029] (1) Take tetrabutyl titanate and anhydrous ethanol in a volume ratio of 1:(3~5), dissolve tetrabutyl titanate in anhydrous ethanol, and stir at room temperature for 5~10 minutes to obtain solution A;

[0030] (2) Mix water, glacial acetic acid and anhydrous ethanol in a volume ratio of 1:1:(20~30) at room temperature for 10~20 minutes to obtain solution B; wherein the volume ratio of glacial acetic acid to tetrabutyl titanate is 1:(6~7).

[0031] (3) Under stirring conditions, add solution B dropwise to solution A at a rate of 0.5~1 mL / min. After the addition is complete, continue the reaction at room temperature for 1.5~3 hours to obtain titanium dioxide sol precursor.

[0032] (4) Tris powder was added to the titanium dioxide sol precursor to adjust the pH of the system to 8-9. Then, dopamine hydrochloride was added and the mixture was stirred at room temperature for 12-36 hours under light-protected conditions. After that, the mixture was centrifuged at 8000-10000 r / min for 10-15 minutes, and the precipitate was collected. The precipitate was washed 1-3 times with deionized water and 1-3 times with anhydrous ethanol. The washed precipitate was dried in a vacuum drying oven at 60-80℃ for 12-24 hours. Then, it was ground using a planetary ball mill for 2-3 hours. The grinding medium was zirconia balls, and the ball-to-material ratio was 10:1 to obtain a modified filler with a particle size of 300-500 nm. Among them, tetrabutyl titanate was calculated as titanium dioxide, and the mass ratio of dopamine hydrochloride to tetrabutyl titanate was 1:(12-15).

[0033] As a preferred embodiment of the present invention, the water-soluble natural polymer is selected from one or more of gelatin, gum arabic, sodium alginate and carboxylated chitosan, preferably carboxylated chitosan.

[0034] The carboxylated chitosan in this invention can be obtained commercially, for example, purchased from Guangdong Mingcheng Biotechnology Co., Ltd.

[0035] In this invention, water-soluble natural polymers (especially carboxylated chitosan) are preferred, which can significantly improve the dispersion stability of the modified filler and enhance the multiple bonding between the outer fabric and the anti-slip coating, thereby obtaining a more uniform, durable anti-slip press-fit cushioning pad that maintains a high coefficient of friction at high temperatures.

[0036] As a preferred embodiment of the present invention, the thickener is selected from one or more of sodium carboxymethyl cellulose, hydroxyethyl cellulose, and sodium polyacrylate, preferably sodium carboxymethyl cellulose. Sodium carboxymethyl cellulose has good thickening, suspending, and stabilizing effects, which can adjust the viscosity of the modified polytetrafluoroethylene coating liquid, avoid sagging and dripping during the coating process, and improve the stability of the coating liquid, prevent the sedimentation of modified fillers and PTFE particles, and ensure uniform coating thickness and smooth surface.

[0037] The sodium carboxymethyl cellulose in this invention is commercially available, for example, purchased from Guangdong Mingcheng Biotechnology Co., Ltd.

[0038] In this invention, the fiberglass cloth refers to glass fiber cloth, preferably electronic grade glass fiber plain weave cloth, and its thickness is not particularly limited, generally 0.15~0.3mm.

[0039] The specific type and thickness of the organic fiber woven layer in this invention can be selected as needed. For example, the organic fiber woven layer can be Kevlar 1414 fiber or Kevlar 1313 fiber, and the thickness can be 5~10mm. Kevlar fiber has excellent tensile strength, impact resistance and wear resistance. Its tensile strength is ≥2000MPa and its elongation at break is ≥2.5%. As the core buffer layer of the cushioning pad, it can effectively absorb external impact force and achieve a good cushioning and rebound effect. At the same time, Kevlar fiber has excellent high temperature resistance and can adapt to various complex usage scenarios. Compared with the traditional polyurethane foam buffer layer, it has better dimensional stability and is not easy to deform after long-term compression.

[0040] In this invention, the anti-slip outer fabric can be bonded to the upper and lower surfaces of the organic fiber woven layer using an adhesive, and the specific type of adhesive is not particularly limited. A high-temperature resistant silicone adhesive is preferred, such as SDL-1-43 silicone rubber adhesive.

[0041] As a preferred embodiment of the present invention, the method for preparing the anti-slip outer fabric includes:

[0042] a) Mix the raw materials for the modified polytetrafluoroethylene layer evenly to obtain a raw material mixture;

[0043] b) Impregnate the fiberglass cloth in the raw material mixture obtained in step a), and then sinter it to obtain PTFE fiberglass cloth;

[0044] c) The PTFE fiberglass cloth is immersed in a sodium-naphthalene treatment solution for sodium treatment, and then removed, washed, dried and heat-treated to obtain the anti-slip outer fabric.

[0045] There are no special restrictions on the mixing method in step a) of the present invention, as long as the raw materials of the modified polytetrafluoroethylene layer can be mixed evenly, for example, mixing at 50~60°C for 30~60 minutes.

[0046] As a preferred technical solution of the present invention, in step b), the impregnation can be carried out in the glue circulation system of the glue applicator, preferably the fiberglass cloth is impregnated in the raw material mixture obtained in step a) at a speed of 35~45cm / min.

[0047] As a preferred embodiment of the present invention, in step b), the coating amount of the raw material mixture is 140~160 g / m². 2 In this invention, excess material can be removed by squeezing with extrusion rollers.

[0048] As a preferred technical solution of the present invention, in step b), the sintering conditions include: segmented baking, the first segment is baked at 110~130℃ for 5~8 minutes, the second segment is pre-sintered at 280~320℃ for 3~5 minutes, and the third segment is finally sintered at 110~130℃ for 8~12 minutes.

[0049] This invention reveals that by controlling the chemical modification of the PTFE fiberglass cloth surface using a sodium-naphthalene treatment solution, sodium atoms effectively break the CF bonds on the PTFE surface, removing some fluorine atoms. This forms a dense carbonized layer on the surface and introduces strongly polar groups such as hydroxyl, carbonyl, and carboxyl groups in situ, while simultaneously constructing a micro-rough porous structure. This significantly improves surface energy and the coefficient of friction, giving the cushioning pad excellent anti-slip properties and fundamentally solving the problem of board slippage and displacement during PCB lamination. Combined with a three-stage segmented baking and sintering process, the first stage at low temperature can fully remove emulsion solvents and moisture, avoiding blistering and pinhole defects. The second stage at medium temperature achieves preliminary melting and plasticization of PTFE, improving coating density and adhesion. The third stage at low temperature further stabilizes the surface structure, reduces internal stress and thermal deformation. While ensuring that the core properties of PTFE, such as high temperature resistance, corrosion resistance, and low precipitation, are not affected, the anti-slip surface layer is uniformly dense, firmly bonded, and the modification depth is controllable. Ultimately, an anti-slip lamination cushioning pad with stable anti-slip properties, excellent cushioning performance, and high temperature resistance and cleanliness is obtained.

[0050] As a preferred technical solution of the present invention, the sodium-naphthalene treatment solution is a sodium-naphthalene-tetrahydrofuran system, wherein the molar ratio of sodium to naphthalene in the sodium-naphthalene-tetrahydrofuran system is 1:1, and the total molar concentration of sodium and naphthalene is 0.8~1.2 mol / L.

[0051] The sodium-naphthalene-tetrahydrofuran system of this invention can be prepared according to conventional methods in the art. For example, sodium metal and refined naphthalene are weighed in a molar ratio of 1:1. Under dry nitrogen protection and ice bath temperature control at 0-10°C, the sodium metal is slowly added to the tetrahydrofuran solution of naphthalene in 3-4 portions, and the mixture is stirred for 1.5-2 hours until completely dissolved to obtain the sodium-naphthalene-tetrahydrofuran system, wherein the total molar concentration of sodium metal and naphthalene is 0.8-1.2 mol / L. After preparation, the system is sealed under nitrogen and stored at low temperature and protected from light.

[0052] As a preferred technical solution of the present invention, in step c), the conditions for the sodium treatment include: treatment at room temperature for 0.5 to 5 minutes, preferably treatment at room temperature for 2 to 3 minutes.

[0053] As a preferred technical solution of the present invention, in step c), the washing method includes: washing in anhydrous ethanol 2 to 3 times, each time for 10 to 30 seconds.

[0054] As a preferred technical solution of the present invention, in step c), the drying conditions include drying at 60~70℃ for 1~2 hours.

[0055] As a preferred technical solution of the present invention, in step c), the heat treatment conditions include: heat treatment at 200~230℃ for 5~10 minutes, which can be achieved by heating rollers.

[0056] In a second aspect, the present invention provides a method for preparing the anti-slip press-fit cushioning pad described in the first aspect of the present invention, comprising the following steps:

[0057] S1. Place the organic fiber woven layer (preferably Kevlar 1414 fiber or Kevlar 1313 fiber woven layer, 5~10mm thick) in a constant temperature drying oven at 100~120℃ and dry for 2~4 hours to remove moisture and residual impurities inside the woven layer. After drying, take it out and cool it to room temperature for later use. During the drying process, avoid excessive temperature to prevent degradation of organic fibers and ensure that the mechanical properties of the woven layer are not affected.

[0058] S2. Using a scraper coating method, apply adhesive (preferably SDL-1-43 silicone rubber adhesive) to the upper and lower surfaces of the pretreated organic fiber woven layer. The coating thickness is controlled to be 0.05~0.1mm, and the coating area is consistent with the surface area of ​​the organic fiber woven layer. (During the coating process, keep the scraper moving at a constant speed to avoid adhesive accumulation, missed coating, etc., and ensure that the coating layer is uniform and flat, laying the foundation for the subsequent bonding of the anti-slip outer fabric) to obtain the pre-composite blank.

[0059] S3. Place the pre-composite blank into a hot press molding machine for hot pressing and curing treatment. The preferred hot pressing and curing conditions are: hot pressing temperature 150~180℃, hot pressing pressure 1.2~1.5MPa, hot pressing time 30~45 minutes. After naturally cooling to room temperature, remove the blank. Preferably, place the hot-pressed and cured blank on a trimming machine and use a CNC trimming knife to remove the excess parts and irregular corners of the blank edges. Preferably, finally place the trimmed cushioning pad into a vacuum drying oven at 60~80℃ and dry for 8~12 hours to obtain an anti-slip pressed cushioning pad.

[0060] Compared with the prior art, the present invention has at least the following beneficial effects:

[0061] 1. The press-fit cushioning pad has excellent anti-slip performance: By coating the surface of the fiberglass cloth with a modified polytetrafluoroethylene layer filled with polydopamine-modified titanium dioxide, and combining it with sodium treatment and heat treatment, the surface friction coefficient of the anti-slip cloth can be improved, effectively solving the problem of the existing cushioning pad sliding and shifting due to inertia during trolley transportation.

[0062] 2. The press-fit buffer pad has excellent wear resistance and mechanical properties: The modified filler (such as polydopamine-coated titanium dioxide nanoparticles) introduced into the modified polytetrafluoroethylene layer works synergistically with Teflon emulsion and water-soluble natural polymers to enhance the density, wear resistance and mechanical properties of the coating. Detailed Implementation

[0063] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Experimental methods in the following embodiments, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer.

[0064] In the following examples and comparative examples:

[0065] The Teflon emulsion is model number POLYFLON™ PTFE D-610C from Daikin Japan.

[0066] Carboxylated chitosan was purchased from Guangdong Mingcheng Biotechnology Co., Ltd.

[0067] Sodium carboxymethyl cellulose was purchased from Guangdong Mingcheng Biotechnology Co., Ltd.

[0068] Example 1

[0069] Preparation of modified fillers:

[0070] (1) Take tetrabutyl titanate and anhydrous ethanol in a volume ratio of 1:4. Dissolve tetrabutyl titanate in anhydrous ethanol and stir at room temperature for 10 minutes to obtain solution A.

[0071] (2) Mix water, glacial acetic acid and anhydrous ethanol in a volume ratio of 1:1:25 at room temperature for 15 minutes to obtain solution B; wherein the volume ratio of glacial acetic acid to tetrabutyl titanate is 1:6.

[0072] (3) Under stirring conditions, solution B was added dropwise to solution A at a rate of 1 mL / min. After the addition was completed, the reaction was continued at room temperature for 2 hours to obtain titanium dioxide sol precursor.

[0073] (4) Tris powder was added to the titanium dioxide sol precursor to adjust the pH of the system to 8.5. Then, dopamine hydrochloride was added and the mixture was stirred at room temperature for 24 hours under light-protected conditions. After that, the mixture was centrifuged at 10,000 r / min for 10 minutes to collect the precipitate. The precipitate was washed twice with deionized water and twice with anhydrous ethanol. The washed precipitate was dried in a vacuum drying oven at 70℃ for 16 hours. Then, it was ground using a planetary ball mill for 2.5 hours. The grinding medium was zirconia balls with a ball-to-material ratio of 10:1 to obtain a modified filler with a particle size of 420 nm. The tetrabutyl titanate was calculated as titanium dioxide, and the mass ratio of dopamine hydrochloride to tetrabutyl titanate was 1:13.

[0074] Preparation of anti-slip outer fabric:

[0075] a) Prepare 50.4 parts of Teflon emulsion, 23.5 parts of modified filler, 2.5 parts of carboxylated chitosan, 0.6 parts of sodium carboxymethyl cellulose and 15 parts of water by weight. Mix the Teflon emulsion, modified filler, carboxylated chitosan, sodium carboxymethyl cellulose and water at 60°C for 50 minutes until they are evenly mixed to obtain the raw material mixture.

[0076] b) Using a coating machine, a 0.2mm thick electronic-grade glass fiber plain weave fabric is impregnated into the raw material mixture obtained in step a) at a speed of 40cm / min. Excess raw material mixture is removed by extrusion rollers, resulting in a coating weight of 150g / m². 2 Then, the impregnated fiberglass cloth was baked in sections. The first section was baked at 120°C for 6 minutes, the second section was pre-sintered at 300°C for 4 minutes, and the third section was finally sintered at 120°C for 10 minutes to obtain PTFE fiberglass cloth.

[0077] c) Weigh out metallic sodium and refined naphthalene in a molar ratio of 1:1. Under dry nitrogen protection and ice bath temperature control of 3±3℃, slowly add metallic sodium to the tetrahydrofuran solution of naphthalene in 3 portions. Stir the reaction for 2 hours until completely dissolved to obtain a metallic sodium-naphthalene-tetrahydrofuran system with a total molar concentration of 1 mol / L. Impregnate PTFE fiberglass cloth in the metallic sodium-naphthalene-tetrahydrofuran system and treat it at room temperature for 3 minutes. After that, remove it and wash it twice in an anhydrous ethanol cleaning tank for 20 seconds each time. Then remove it and dry it at 65℃ for 1.5 hours. Finally, heat treat it with a 225℃ heating roller for 8 minutes to obtain the anti-slip outer fabric.

[0078] Preparation of anti-slip press-fit cushioning pad:

[0079] S1. Pre-treatment of organic fiber braided layer: Place the 8mm thick Kevlar 1414 fiber braided layer in a constant temperature drying oven at 110℃ for 3 hours to remove internal moisture and impurities, and then cool it to room temperature for later use.

[0080] S2. Applying adhesive: Using a scraper coating method, evenly apply SDL-1-43 silicone rubber adhesive to the upper and lower surfaces of the Kevlar braided layer, with a coating thickness of 0.08mm, ensuring uniform coating without any missed areas;

[0081] S3, Composite Anti-slip Outer Fabric: Two pieces of the prepared anti-slip outer fabric are aligned and bonded to the upper and lower surfaces of the woven layer, respectively. They are then pressed with a pressure roller at a pressure of 0.4 MPa and a speed of 25 cm / min to remove air bubbles between the layers.

[0082] S4. Hot pressing and curing: Place the blank into a hot press molding machine, heat it to 165℃ at 5℃ / min, maintain the pressure of 1.3MPa for 35 minutes, and remove it after it cools naturally to room temperature;

[0083] S5. Trimming: Use a CNC trimming knife to remove excess material from the edges and trim to the preset size, ensuring a smooth cut without burrs.

[0084] S6. Post-processing: Place the cushioning pad in a 70℃ vacuum drying oven and dry for 10 hours to obtain an anti-slip pressed cushioning pad.

[0085] Example 2

[0086] The method according to Example 1 differs in that,

[0087] In the preparation of the anti-slip outer fabric: a) 53 parts of Teflon emulsion, 22 parts of modified filler, 2 parts of carboxylated chitosan, 0.8 parts of sodium carboxymethyl cellulose, and 14 parts of water are prepared; b) the first stage is baked at 130℃ for 5 minutes, the second stage is pre-sintered at 320℃ for 3 minutes, and the third stage is finally sintered at 110℃ for 12 minutes to obtain PTFE fiberglass cloth; c) finally, it is heat-treated by a 230℃ heating roller for 6 minutes to obtain the anti-slip outer fabric.

[0088] The rest is the same as in Example 1, and the final anti-slip press-fit cushioning pad is obtained.

[0089] Example 3

[0090] The method according to Example 1 differs in that,

[0091] Preparation of modified fillers:

[0092] (1) Take tetraethyl orthosilicate and anhydrous ethanol in a volume ratio of 1:4. Dissolve tetraethyl orthosilicate in anhydrous ethanol and stir at room temperature for 10 minutes to obtain solution A.

[0093] (2) Mix water, glacial acetic acid and anhydrous ethanol in a volume ratio of 1:1:25 at room temperature for 15 minutes to obtain solution B; wherein the volume ratio of glacial acetic acid to tetraethyl orthosilicate is 1:6.

[0094] (3) Under stirring conditions, solution B was added dropwise to solution A at a rate of 1 mL / min. After the addition was completed, the temperature was raised to 50 °C and reacted for 4 hours to obtain silica sol precursor.

[0095] (4) Tris powder was added to the silica sol precursor to adjust the pH of the system to 8.5. Then, dopamine hydrochloride was added and the mixture was stirred at 50°C for 12 hours under light-protected conditions. After that, the mixture was centrifuged at 10000 r / min for 10 minutes to collect the precipitate. The precipitate was washed twice with deionized water and twice with anhydrous ethanol. The washed precipitate was dried in a vacuum drying oven at 70°C for 16 hours. Then, it was ground using a planetary ball mill for 2.5 hours. The grinding medium was zirconia balls with a ball-to-material ratio of 10:1 to obtain a modified filler with a particle size of 500 nm. In this case, tetraethyl orthosilicate was calculated as silica, and the mass ratio of dopamine hydrochloride to tetraethyl orthosilicate was 1:13.

[0096] The rest is the same as in Example 1, and the final anti-slip press-fit cushioning pad is obtained.

[0097] Example 4

[0098] The method according to Example 1 differs in that,

[0099] The modified filler was replaced with KH570 coupling agent nano-titanium oxide, which was purchased from Xuancheng Jingrui New Materials Co., Ltd., model VK-T60S.

[0100] The rest is the same as in Example 1, and the final anti-slip press-fit cushioning pad is obtained.

[0101] Example 5

[0102] The method according to Example 1 differs in that,

[0103] Preparation of anti-slip outer fabric: c) without heat treatment by a 225°C heating roller for 8 minutes, then take it out and dry it at 65°C for 1.5 hours to obtain the anti-slip outer fabric.

[0104] The rest is the same as in Example 1, and the final anti-slip press-fit cushioning pad is obtained.

[0105] Example 6

[0106] The method according to Example 1 differs in that,

[0107] Preparation of anti-slip fabric: b) Replace the segmented baking with a single-stage baking, specifically sintering at 240℃ for 15 minutes.

[0108] The rest is the same as in Example 1, and the final anti-slip press-fit cushioning pad is obtained.

[0109] Comparative Example 1

[0110] The method according to Example 1 differs in that,

[0111] Preparation of anti-slip fabric: a) Prepare 50.4 parts of Teflon emulsion, 23.5 parts of modified filler, 3.1 parts of sodium carboxymethyl cellulose and 15 parts of water by weight. Mix the Teflon emulsion, modified filler, sodium carboxymethyl cellulose and water at 60°C for 50 minutes until the mixture is homogeneous to obtain the raw material mixture.

[0112] The rest is the same as in Example 1, and the final anti-slip press-fit cushioning pad is obtained.

[0113] Comparative Example 2

[0114] The method according to Example 1 differs in that,

[0115] The modified filler was replaced with TR-215 rutile titanium dioxide.

[0116] The rest is the same as in Example 1, and the final anti-slip press-fit cushioning pad is obtained.

[0117] Performance testing

[0118] 1. Abrasion resistance test: Cut the anti-slip press-fit buffer pad into circular specimens with a diameter of 100mm. Test three parallel specimens for each sample. Weigh the specimens before testing (accurate to 0.1mg). Refer to GB / T5478-2008 "Plastic Rolling Abrasion Test" (Taber Abrasion Method) to test the mass of the circular specimens after wear (accurate to 0.1mg). Test conditions: grinding wheel load 500g, turntable speed 60rpm, total number of revolutions: 1000 revolutions, sandpaper replaced and grinding wheel cleaned every 500 revolutions. Calculate the mass loss and obtain the average mass loss of the three specimens. The smaller the mass loss, the better the abrasion resistance.

[0119] 2. Anti-slip test: The surface friction coefficient of the anti-slip press-fit cushioning pad is tested according to GB / T 10006-2001 standard. The higher the friction coefficient, the better the anti-slip performance.

[0120] 3. Tensile strength and elongation at break tests: The tensile strength and elongation at break of the anti-slip press-fit cushioning pad are tested according to GB / T 528-2009 standard.

[0121] 4. Tear strength test: The tear strength of the anti-slip press-fit cushioning pad is tested according to GB / T 529-2008 standard.

[0122] The performance test results are shown in Table 1.

[0123] Table 1 Performance Test Results

[0124]

[0125] As can be seen from the comparison of the embodiments and comparative examples, the press-fit cushioning pad of the present invention has excellent anti-slip properties, wear resistance, tensile and tear strength.

[0126] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details of the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention. Furthermore, various different embodiments of the present invention can be arbitrarily combined, as long as they do not violate the spirit of the present invention, they should also be considered as the content disclosed by the present invention.

Claims

1. A non-slip press-fit cushioning pad, characterized in that, The invention includes an anti-slip outer fabric disposed on the upper and lower surfaces of an organic fiber woven layer. The anti-slip outer fabric comprises fiberglass cloth and a modified polytetrafluoroethylene layer coated on the surface of the fiberglass cloth. The modified polytetrafluoroethylene layer comprises, by weight, 40-60 parts of Teflon emulsion, 15-30 parts of modified filler, 1-5 parts of water-soluble natural polymer, 0.1-1 parts of thickener, and 10-20 parts of water.

2. The anti-slip press-fit cushioning pad according to claim 1, characterized in that, By weight, the raw materials for the modified polytetrafluoroethylene layer include: 48-53 parts of Teflon emulsion, 22-25 parts of modified filler, 2-2.5 parts of water-soluble natural polymer, 0.5-0.8 parts of thickener, and 14-17 parts of water.

3. The anti-slip press-fit cushioning pad according to claim 1 or 2, characterized in that, The method for preparing the modified filler includes: (1) Dissolve tetrabutyl titanate in anhydrous ethanol to obtain solution A; (2) Mix water, glacial acetic acid and anhydrous ethanol to obtain solution B; (3) Add solution B dropwise to solution A, and continue the reaction after the addition is complete to obtain titanium dioxide sol precursor; (4) Tris powder was added to the titanium dioxide sol precursor to adjust the pH of the system to 8-9, and then dopamine hydrochloride was added to carry out the polymerization reaction. After that, the mixture was centrifuged, washed, dried and ground to obtain the modified filler.

4. The anti-slip press-fit cushioning pad according to claim 3, characterized in that, In step (1), the volume ratio of tetrabutyl titanate to anhydrous ethanol is 1:(3~5); in step (2), the volume ratio of water, glacial acetic acid and anhydrous ethanol is 1:1:(20~30); and the volume ratio of glacial acetic acid to tetrabutyl titanate is 1:(5~10).

5. The anti-slip press-fit cushioning pad according to claim 3, characterized in that, In step (3), the dropping rate of solution B is 0.5~1 mL / min; in step (3), the reaction conditions include: reacting at room temperature for 1.5~3 hours; the mass ratio of tetrabutyl titanate to dopamine hydrochloride to tetrabutyl titanate is 1:(10~20) based on titanium oxide; in step (4), the polymerization reaction conditions include: stirring at room temperature for 12~36 hours under light-protected conditions.

6. The anti-slip press-fit cushioning pad according to claim 3, characterized in that, In step (4), the centrifugation conditions include: centrifuging at 8000~10000 r / min for 10~15 minutes; in step (4), the washing method includes: washing with deionized water 1~3 times and washing with anhydrous ethanol 1~3 times in sequence; in step (4), the drying conditions include: drying in a vacuum drying oven at 60~80℃ for 12~24 hours.

7. The anti-slip press-fit cushioning pad according to claim 1 or 2, characterized in that, The water-soluble natural polymer is selected from one or more of gelatin, gum arabic, sodium alginate and carboxylated chitosan; the thickener is selected from one or more of sodium carboxymethyl cellulose, hydroxyethyl cellulose and sodium polyacrylate.

8. The anti-slip press-fit cushioning pad according to claim 1 or 2, characterized in that, The method for preparing the anti-slip outer fabric includes: a) Mix the raw materials for the modified polytetrafluoroethylene layer evenly to obtain a raw material mixture; b) Impregnate the fiberglass cloth in the raw material mixture obtained in step a), and then sinter it to obtain PTFE fiberglass cloth; c) The PTFE fiberglass cloth is immersed in a sodium-naphthalene treatment solution for sodium treatment, and then removed, washed, dried and heat-treated to obtain the anti-slip outer fabric.

9. The anti-slip press-fit cushioning pad according to claim 8, characterized in that, In step b), the sintering conditions include: segmented baking, with the first segment baked at 110~130℃ for 5~8 minutes, the second segment pre-sintered at 280~320℃ for 3~5 minutes, and the third segment final sintered at 110~130℃ for 8~12 minutes; in step c), the sodium treatment conditions include: treatment at room temperature for 0.5~5 minutes, preferably treatment at room temperature for 2~3 minutes.

10. A method for preparing an anti-slip press-fit cushioning pad according to any one of claims 1 to 9, characterized in that, Includes the following steps: S1. Place the organic fiber woven layer in a constant temperature drying oven at 100~120℃ and dry for 2~4 hours to remove moisture and residual impurities inside the woven layer. After drying, take it out and cool it to room temperature for later use. S2. Using a scraper coating method, the adhesive is coated on the upper and lower surfaces of the pretreated organic fiber woven layer. The coating thickness is controlled to be 0.05~0.1mm, and the coating area is consistent with the surface area of ​​the organic fiber woven layer, thus obtaining the preform after preliminary composite. S3. Place the pre-composite blank into a hot press molding machine for hot pressing and curing treatment. After naturally cooling to room temperature, remove the blank to obtain an anti-slip press-fit cushioning pad.

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