Decorative paper capable of permanently releasing negative oxygen ions, preparation method and control system

Abstract

The invention relates to the technical field of decorative paper, in particular to decorative paper capable of releasing negative oxygen ions permanently, a preparation method and a control system.The decorative paper comprises a decorative paper base material and a composite coating, and the composite coating is sequentially arranged on the base material in a stacked mode from inside to outside and comprises an adhesion bottom layer, a gradient function core layer and a wear-resistant transparent surface layer; the gradient functional core layer is composed of at least one functional lower layer and a functional upper layer, and the concentration of negative oxygen ion materials in the functional upper layer is higher than that of the functional lower layer. The problems that in the prior art, the negative oxygen ion release function is rapidly attenuated, the coating performance is insufficient, and the product quality is unstable due to low control precision in the preparation process are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of decorative paper, and more particularly to decorative paper capable of persistently releasing negative oxygen ions, a preparation method and a control system. Background Art

[0002] Decorative paper, as an important interior decoration material, is widely used in areas such as walls and furniture surfaces. With increasing awareness of health and the environment, decorative paper with negative oxygen ion-releasing properties is gaining market favor. Negative oxygen ions are believed to help purify the air and improve human health, so incorporating negative oxygen ion materials into decorative paper holds significant potential for application.

[0003] However, existing negative oxygen ion decorative paper faces many challenges in practical application, especially in ensuring the long-term, stable, and efficient release of negative oxygen ions while maintaining the decorative paper's inherent functional properties such as wear resistance, stain resistance, and weather resistance. Existing technologies use a relatively simple method of simply dispersing unmodified negative oxygen ion powder in a single layer of coating, but this often leads to the following problems:

[0004] First, negative oxygen ion powders have poor dispersibility and are easy to agglomerate in organic coating systems, resulting in uneven distribution after curing, which limits the effective release channels of negative oxygen ions.

[0005] Secondly, the lack of optimized interlayer structure design makes it difficult for negative oxygen ions to penetrate the surface layer, or the negative oxygen ion material in the functional layer is easily fallen off due to wear, seriously affecting its functional durability.

[0006] Thirdly, negative oxygen ion materials without surface modification may have poor compatibility with the resin system, affecting the mechanical properties and appearance quality of the coating.

[0007] Finally, existing technologies often use static or experience-based process control methods during the preparation process, especially in the precision coating and curing stages.

[0008] During precision coating processes (such as slot-die coating), parameters such as the substrate's surface condition (surface energy, roughness), operating speed, tension, and the coating's rheological properties (viscosity, temperature, and solids content) fluctuate in real time. Traditional coating control systems struggle to precisely adjust to these real-time changes, resulting in uneven wet film thickness and defects such as sagging, orange peel, and streaking, impacting both product appearance and the consistency of the functional layer thickness.

[0009] During the coating curing process, especially when using electron beam (EB) irradiation curing technology, which offers high efficiency and environmental benefits, the curing dose is a key parameter that determines the degree of crosslinking and final properties of the coating (such as hardness, adhesion, and chemical resistance). However, the actual wet film thickness of the coating before entering the curing zone (affected by coating fluctuations) and the actual operating speed of the production line may vary, directly affecting the actual EB dose received by the coating. Traditional EB curing equipment typically uses a fixed dose or simple speed compensation, and is unable to accurately adjust the dose dynamically based on real-time coating thickness and speed changes. This can lead to uneven curing, under-curing (affecting performance and durability), or over-curing (which may cause paper brittleness, color changes, and increased energy consumption), which seriously affects product quality stability, functional sustainability, and production efficiency.

[0010] In summary, the existing technology lacks a systematic solution for achieving the sustained release function of negative oxygen ion decorative paper by optimizing material dispersion, improving interlayer structure design, and combining intelligent and high-precision dynamic control of the preparation process. In particular, there are significant technical gaps and room for improvement in the key links of coating thickness control and curing dosage control. Summary of the Invention

[0011] To this end, the purpose of the present invention is to provide a decorative paper with long-lasting release of negative oxygen ions and a preparation method thereof, aiming to solve the problems in the prior art such as rapid attenuation of the negative oxygen ion release function, insufficient coating performance, and low control precision of the preparation process leading to unstable product quality.

[0012] To achieve the above object, the present invention provides the following technical solutions:

[0013] A decorative paper capable of persistently releasing negative oxygen ions, comprising:

[0014] Decorative paper substrate;

[0015] The composite coating is sequentially stacked on the substrate from the inside out, comprising:

[0016] Attachment to the bottom layer;

[0017] Gradient functional core layer;

[0018] Wear-resistant and transparent surface;

[0019] The gradient functional core layer is composed of at least one functional lower layer and one functional upper layer, and the concentration of negative oxygen ion material in the functional upper layer is higher than that in the functional lower layer.

[0020] The present invention is further configured as follows: the gradient functional core layer comprises a composite powder material, and the composite powder material comprises:

[0021] Core-shell surface-modified tourmaline powder with an average particle size of 5-15 μm;

[0022] Photocatalytic nano-titanium dioxide, with an average particle size of 20-50nm;

[0023] The weight ratio of the modified tourmaline micropowder to nano-titanium dioxide is 1:1 to 3:1, and meets the following conditions: tourmaline particle size / titanium dioxide particle size ≥ 300.

[0024] The present invention is further configured as follows: the tourmaline powder is modified by coating with silicon dioxide, the coating layer thickness is 5-20 nm, and the band gap width of the photocatalytic nano-titanium dioxide is ≤3.2 eV.

[0025] The present invention is further configured as follows: in the gradient functional core layer:

[0026] The composite powder of the functional upper layer accounts for 30-50wt% of the total solid content of the coating;

[0027] The composite powder of the functional lower layer accounts for 10-25wt% of the total solid content of the coating;

[0028] The difference in composite powder concentration between the functional upper layer and the functional lower layer is ≥15wt%.

[0029] The present invention is further configured such that the wear-resistant and transparent surface layer is formed by curing a formula comprising the following components:

[0030] Aliphatic polyurethane acrylate: 50-70wt%;

[0031] Monomer or oligomer: 20-30wt%;

[0032] Photoinitiator: 3-8wt%;

[0033] After curing, a dense cross-linked structure with a pencil hardness of ≥2H is formed, and microscopic channels with an average pore size of 5-50nm exist in the structure.

[0034] A method for preparing decorative paper, comprising sequentially performing:

[0035] S1. Material preparation step: preparing a gradient functional core layer coating;

[0036] S2, precision coating step: coating the adhesive base layer, gradient functional core layer and wear-resistant transparent surface layer on the substrate in sequence;

[0037] S3, adaptive curing step: electron beam curing is performed under a nitrogen protection environment.

[0038] The present invention is further configured as follows: wherein step S1 includes the following steps:

[0039] Under a constant temperature of 45±2°C, the acrylate resin and 0.8-1.5% of the resin weight of the polyether-modified silicone dispersant were mixed at 800-1200 rpm for 120±10 seconds to form an activated matrix;

[0040] Step dispersion stage: Take 30±2% of the activated matrix and all the composite powders for four-step high shear dispersion, and perform the following steps in sequence:

[0041] Crushing stage: Run at 2500±50rpm for 40±5 seconds, and simultaneously control the temperature change rate to ≤2℃ / second, until the fineness reaches 30μm;

[0042] Transition stage: switch to 2200±50rpm and run for 60±5 seconds, maintaining a constant temperature of 45±1℃ until the fineness reaches 20μm;

[0043] Fine grinding stage: Run at a basic speed of 1800±50rpm for 90±5 seconds. During this period, the speed is dynamically adjusted according to the real-time viscosity η according to the formula:

[0044] ;

[0045] Until the fineness reaches 15μm;

[0046] Homogenization stage: reduce the speed to 1500±50rpm and run for 120±10 seconds. The process is terminated when D90≤10μm and the standard deviation σ<0.5μm for 5 consecutive samples.

[0047] Gradient dilution stage: The concentrated masterbatch is pumped into the remaining activated matrix, which is controlled in three stages:

[0048] Phase 1: Delivery through a static mixer at a flow rate of 4.5 ± 0.5 L / min for 30 seconds;

[0049] Phase 2: Reduce the speed to 3.0 ± 0.3 L / min and start 40 kHz ultrasound assistance for 30 seconds;

[0050] The third stage: the speed is reduced to 1.5±0.2L / min and transported through the static mixer for 30 seconds.

[0051] The present invention is further configured as follows: in the fine grinding stage, by real-time monitoring of the motor current fluctuation spectrum, when the ratio of the integral value of the power spectrum density in the 5-10kHz frequency band to the integral value of the full frequency band (0-20kHz) is greater than 0.35, the homogenization stage is entered in advance.

[0052] The present invention is further configured such that step S2 is implemented using a slit coating head, and the coating thickness is controlled by a closed-loop control system, the system comprising:

[0053] An online non-contact thickness sensor located downstream of the coating station;

[0054] Servo metering pump linked to the sensor;

[0055] Achieve coating thickness error ≤±2μm, and when coating the functional upper layer:

[0056] Line speed reduced by 30-50%;

[0057] Paint flow rate increased by 40-60%;

[0058] Synchronous start temperature compensation: ,

[0059] in is the coating temperature (℃), is the real-time linear speed (m / min).

[0060] An adaptive control system for curing negative oxygen ion decorative paper, comprising:

[0061] Environmental control module, maintaining nitrogen protection environment with oxygen concentration <200ppm;

[0062] The electron beam generating module is configured to output an electron beam with an accelerating voltage of 150-180 kV, a beam current of 10-30 mA, and a linear speed adaptation range of 10-30 m / min;

[0063] The dose compensation module receives the wet film thickness signal T and the line speed signal v in real time, and outputs the electron beam parameter adjustment signal through the compensation algorithm;

[0064] Energy coupling module, real-time acquisition of cumulative energy density from the dispersion process data;

[0065] The compensation formula is:

[0066]

[0067] Among them, k=0.15-0.35 Gy / μm², α=0.05-0.12 Gy;

[0068] described Calculated by the following formula:

[0069]

[0070] Among them: i=1, 2, 3, 4 correspond to the crushing stage, transition stage, fine grinding stage, and homogenization stage respectively;

[0071] is the slurry density at each stage (kg / m³); is the actual speed at each stage (rpm); is the duration (s); is the stage correction coefficient.

[0072] Compared with the shortcomings of the prior art, the beneficial effects of the present invention are:

[0073] Through the multi-layer precision coating design of "adhesion bottom layer-functional lower layer-functional upper layer-wear-resistant and transparent surface layer", the precise stratification and functional gradient distribution of materials are achieved, ensuring the stable loading and uniform release of negative oxygen ion materials and optimizing surface properties.

[0074] By dispersing and fixing the negative oxygen ion powder in the functional layer and protecting the wear-resistant and transparent surface, the continuous and stable release of negative oxygen ions is ensured throughout the product life cycle, solving the problem of rapid release decay and short lifespan of traditional products.

[0075] The electron beam cured resin system has a high cross-linking density and excellent chemical stability, which enables the product to maintain stable performance under different environmental conditions (such as light and humidity) and extend its service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0076] Figure 1 Flowchart of the present invention. DETAILED DESCRIPTION

[0077] A decorative paper with the ability to release negative oxygen ions in a long-lasting manner, the core of which is a multi-layer composite structure, which consists of the following layers from the inside out (i.e., from the closest layer to the surface): decorative paper substrate, adhesive bottom layer, gradient functional core layer and wear-resistant transparent surface layer. Figure 1 As shown:

[0078] Decorative paper substrates preferably feature a high basis weight (e.g., 70-120 g / m²), high density, a smooth surface, and good ink absorbency. For example, base paper made from high-quality wood pulp fibers is preferred. This high-strength substrate provides stable physical support for subsequent multi-layer coatings, and a good surface condition is a prerequisite for achieving high-quality coatings.

[0079] The composite coating is an ingenious four-layer structure designed as follows:

[0080] Adhesion primers establish a strong physical and chemical connection between the substrate and the gradient functional core layer, providing excellent interlayer adhesion. They also pre-seal the substrate to prevent excessive penetration of subsequent functional coatings, which could affect surface uniformity and performance. Typically, low-viscosity, high-permeability acrylic resin systems (polyester acrylates, epoxy acrylates, or oligomeric aliphatic urethane acrylates) are used, which cure rapidly under electron beam irradiation.

[0081] Multifunctional acrylate monomers or oligomers (such as trimethylolpropane triacrylate (TMPTA), hexanediol diacrylate (HDDA), and dipentaerythritol hexaacrylate (DPHA)) can be added as reactive diluents to adjust viscosity and increase crosslink density. A small amount of adhesion promoters (such as phosphate-containing acrylates or silane coupling agents) can be added to enhance adhesion to the substrate, and leveling agents (such as polyether-modified siloxanes) can be added to improve coating smoothness.

[0082] The wet film coating weight of the adhesive base layer is usually controlled at 5-8g / m², and the dry film thickness after curing is 3-5μm. The wet film thickness can be controlled by precision coating equipment, using electron beam pre-curing with a dose controlled at 10-30kGy.

[0083] Gradient functional core layer: This layer is the "engine" and "warehouse" for the production and storage of negative oxygen ions. It consists of two sub-layers, the functional lower layer and the functional upper layer, and is continuously formed through a wet coating process.

[0084] Functional lower layer: Located adjacent to the base layer, this layer contains a relatively low concentration of composite powder in the coating formulation, accounting for 10-25% by weight of the total coating solids (i.e., the sum of all non-volatile components, including resin, additives, and powder). This layer serves as a strategic reserve of negative ions, and its low concentration allows for a smoother and more sustained ion release process.

[0085] The functional upper layer, located above the functional lower layer and closer to the external environment, features a significantly increased coating formulation containing a significantly higher concentration of composite powder, representing 30-50% by weight of the total coating solids. This layer acts as a "high-efficiency release zone," providing a strong initial concentration of negative ions and rapidly improving ambient air quality.

[0086] Concentration difference requirement: To ensure the significance of the gradient effect, the concentration difference of the composite powder between the functional upper layer and the functional lower layer is strictly controlled to ≥15wt%.

[0087] The core component of this layer is composite powder. The core-shell structure modified tourmaline micropowder serves as a spontaneous negative oxygen ion release source, which continuously and stably produces negative oxygen ions without any external energy excitation.

[0088] Raw tourmaline micropowder tends to agglomerate in organic resins. This is modified by silica coating, where a dense silica shell with a thickness of 5-20 nm is in situ formed on the surface of the tourmaline particles via a liquid phase method. This shell significantly improves its dispersibility and stability in the coating and enhances compatibility with the organic resin. The average particle size (D50) of the tourmaline micropowder is selected to be 5-15 μm.

[0089] Photocatalytic nano-titanium dioxide acts as an excited negative oxygen ion release source. When exposed to indoor visible light or ultraviolet light, it produces photogenerated electron-hole pairs inside, which react with water and oxygen in the air to generate a large number of additional negative oxygen ions, achieving an enhanced effect.

[0090] To ensure effective activation by indoor lighting, anatase nano-titanium dioxide with a band gap of ≤3.2eV is preferred. Its average particle size is controlled between 20-50nm. The weight ratio of modified tourmaline to nano-titanium dioxide is controlled between 1:1 and 3:1 to balance the basic release and light enhancement effects. At the same time, by controlling the particle size ratio of the two (tourmaline particle size / titanium dioxide particle size) to ≥300, a microscopic "satellite structure" is formed, that is, smaller nano- The particles can be partially adsorbed on the surface of larger modified tourmaline particles, and this structure is conducive to energy transfer and synergistic effects.

[0091] Wear-resistant and transparent surface: directly exposed to external physical wear, chemical corrosion and stains.

[0092] Formula composition: Aliphatic polyurethane acrylate (50-70wt%) as the main resin, its molecular structure gives the coating excellent flexibility, yellowing resistance and chemical resistance;

[0093] Monomers or oligomers (20-30 wt%) such as hexanediol diacrylate (HDDA) are used as reactive diluents to adjust the viscosity of the coating and participate in the cross-linking reaction to increase the curing speed and cross-linking density.

[0094] Photoinitiator (3-8wt%): After electron beam curing, this layer forms a dense, highly cross-linked network with a pencil hardness of ≥2H, effectively resisting everyday scratches. Furthermore, precise control of the curing dosage creates a large number of microscopic channels with an average pore size of 5-50nm within this dense network. These channels are much smaller than water molecules and common pollutants, yet large enough to allow negative oxygen ions, with diameters significantly smaller than 1nm, to escape.

[0095] The present invention provides a highly intelligent and precise preparation method for decorative paper.

[0096] S1. Material preparation steps:

[0097] The premixing stage activates the resin, reducing its initial viscosity and allowing the dispersant molecules to fully expand, preparing for subsequent powder encapsulation. In a jacketed reactor, the acrylic resin is heated to 45±2°C. A polyether-modified siloxane dispersant (which exhibits excellent wettability and compatibility with acrylic systems) is added at a concentration of 0.8-1.5% by weight of the resin. The mixture is stirred at a low speed of 800-1200 rpm for 120±10 seconds to form a uniform activated matrix.

[0098] Step dispersion stage: break up the agglomerated composite powder to the original particle size with the highest efficiency and minimum energy input, and stably coat it. Take 30±2% of the activated matrix and all the composite powder (i.e. modified tourmaline and nano The mixture is placed in a high-speed disperser for four-stage dispersion:

[0099] Crushing stage: Run at a high-speed impact speed of 2500 ± 50 rpm for 40 ± 5 seconds. This stage maximizes shear force, aiming to rapidly break up large aggregates. Simultaneously, the cooling jacket strictly controls the slurry temperature change rate to ≤ 2°C / second to prevent local overheating that can lead to resin gelation. The goal is to quickly achieve a fineness of 30 μm.

[0100] Transition stage: The speed is reduced to 2200±50rpm and the operation is carried out for 60±5 seconds. The shear force in this stage is moderate, and its main function is to further break up smaller agglomerates. At the same time, the temperature is precisely controlled at 45±1℃ to maintain the optimal dispersion viscosity of the system, with a target fineness of 20μm.

[0101] Fine grinding stage: run at a basic speed of 1800±50rpm for 90±5 seconds. In this stage, viscosity-speed feedback control is introduced, and the real-time viscosity η is monitored by an online viscometer, and the viscosity is calculated according to the formula , dynamically fine-tune the speed to ensure that the grinding process is always in the most efficient range. In addition, by monitoring the spectrum of the disperser motor current, when it is found that the energy in the 5-10kHz frequency band (representing high-frequency collisions between particles) has dropped to a certain level (the integral value ratio of the power spectrum density > 0.35), it indicates that the effective grinding process has come to an end and it can be transferred to the next stage in advance to avoid ineffective energy consumption. The target fineness is 15μm. Homogenization stage: the speed is reduced to 1500±50rpm and runs for 120±10 seconds. This stage aims to make the entire slurry system uniform. Continuous sampling is carried out through the online particle size analyzer. When the particle size distribution D90 measured for 5 consecutive times is ≤10μm and the standard deviation σ is <0.5μm, the dispersion is judged to be complete and automatically terminated.

[0102] Gradient dilution stage: dilute the high-viscosity concentrated masterbatch into the remaining activated matrix safely and without agglomeration, using three-stage variable flow rate control:

[0103] The first stage: pump at a high flow rate of 4.5±0.5L / min for 30 seconds and perform preliminary mixing in a static mixer.

[0104] The second stage: reduce the speed to 3.0±0.3L / min, and start the 40kHz pipeline ultrasonic generator to further prevent the instantaneous agglomeration of particles during the dilution process by using the ultrasonic cavitation effect, which lasts for 30 seconds.

[0105] The third stage: Reduce the speed again to 1.5±0.2L / min and slowly complete the final dilution process to ensure that the system is highly uniform.

[0106] S2. Precision coating step: Ultra-high precision coating is achieved through an advanced feedforward-feedback composite control system. The wet film thickness is measured in real time by an online non-contact thickness sensor (such as a beta ray or laser sensor) set downstream of the coating station. After comparing with the set value, the PID controller calculates the deviation and instructs the servo metering pump to accurately adjust the coating supply flow to achieve closed-loop control with a thickness error of ≤±2μm. When the system switches to coating the functional upper layer coating with the highest viscosity and the highest solid content, the control system pre-emptively and actively adjusts the process parameters: reduces the production line speed by 30-50% to provide a longer leveling time for high-viscosity coatings. Increase the base flow rate of the coating at this station by 40-60% to compensate for the reduction in coating amount due to the reduction in line speed. At the same time, start temperature compensation for the coating according to the formula Preheat the paint, is the target coating temperature (℃), is the real-time line speed (m / min). This formula aims to reduce the viscosity of the coating by increasing the temperature, further improving the coating performance.

[0107] S3, Adaptive curing step: carried out in a nitrogen atmosphere with an oxygen concentration of <200ppm. Its core is an adaptive dosage control system coupled with the material preparation history. System modules:

[0108] Environmental control module: maintains nitrogen purity and positive pressure in the curing area.

[0109] Electron beam generating module: It is configured to output an electron beam with an accelerating voltage of 150-180kV and a beam current of 10-30mA, and is suitable for a production line speed range of 10-30m / min.

[0110] Energy coupling module: Obtain and calculate the cumulative energy density applied to the coating during the dispersion process in real time from the control system of step S1 This value is a quantitative indicator for evaluating the dispersion state of the slurry and the degree of particle surface activation.

[0111] Dosage compensation module: It receives the real-time wet film thickness T, line speed v and the energy coupling module The optimal target curing dose is calculated through a multi-factor compensation algorithm. , and instruct the electron beam generating module to adjust parameters.

[0112] Core compensation algorithm: ,

[0113] in: It is the basic curing dose setting value. is the quadratic thickness compensation term. k is the thickness compensation coefficient (range: 0.15-0.35 Gy / μm²), and 50 is the reference thickness. This quadratic term more accurately describes the nonlinear absorption effect of thick coatings on electron beam energy. is the scattered energy coupling compensation term, is the energy coupling coefficient (range 0.05-0.12 Gy), is the cumulative energy density, calculated as follows:

[0114]

[0115] This formula quantifies the total mechanical energy applied to the coating by summing the energy input of the four dispersion stages (i=1,2,3,4): crushing, transition, fine grinding, and homogenization.

[0116] The specific meanings of the parameters in the formula are as follows:

[0117] The density of slurry at each stage (kg / m³): This value is not fixed and will be fine-tuned as the powder is added and the dispersion state changes. It can be measured by an online density meter or calculated based on the material ratio.

[0118] Actual speed (rpm) at each stage: represents the actual speed (rpm) at each stage. The speed appears as a cube because, in turbulent flow, the power input from the agitator to the fluid is approximately proportional to the cube of the speed. This highlights that speed is the most critical and sensitive parameter affecting energy injection.

[0119] Duration (s): Indicates the duration of each stage (s), which directly determines the accumulated energy at that power

[0120] The stage correction factor is a dimensionless, empirical factor that depends on the equipment and material characteristics. It integrates the effects of factors such as the geometry of the disperser (diameter, blade angle), the size and proportions of the container, and the rheological properties of the slurry at each stage (viscosity change) on energy transfer efficiency. This factor must be calibrated experimentally to ensure the accuracy of the E_d calculation.

[0121] More than just an energy value, it represents the “material preparation history” of the coating, that is, the complete processing path that the slurry has gone through to reach its final dispersed state. A higher surface energy generally means more thorough breakup of powder agglomerates, exposing more of the original particle surface, leading to higher surface free energy. Particles with this high surface energy are also more reactive when entering the curing zone, potentially affecting the kinetics of electron beam-induced crosslinking and curing reactions. For example, a higher surface energy may promote the wetting and adhesion of resin monomers to the particle surface, thereby achieving an ideal crosslink density at a lower curing dose.

[0122] Implementation content:

[0123] Decorative paper base material: Made of 100g / m² high-quality coniferous wood pulp decorative base paper.

[0124] Acrylate resin: Laromer® series EB curing resin produced by BASF is used.

[0125] Polyether modified silicone dispersant: BYK-333 produced by BYK.

[0126] Tourmaline micropowder: Purchase tourmaline micropowder modified by silica coating, with a coating layer thickness of 10nm.

[0127] Nano-titanium dioxide: Purchase anatase nano-titanium dioxide with a band gap of 3.1eV.

[0128] Example 1:

[0129] Composite powder: modified tourmaline powder (average particle size 15μm) and nano titanium dioxide (average particle size 20nm) are mixed in a weight ratio of 1:1. The particle size ratio is 750.

[0130] Gradient functional core layer: the composite powder in the functional upper layer accounts for 30wt% of the total solid content of the coating; the composite powder in the functional lower layer accounts for 10wt% of the total solid content of the coating, and the concentration difference is 20wt%.

[0131] Wear-resistant and transparent surface layer: 70wt% aliphatic polyurethane acrylate; 20wt% monomer or oligomer; 3wt% photoinitiator. At 43°C, mix the acrylate resin with 0.8% dispersant by weight at 800rpm for 130 seconds. Take 28% of the activated matrix and all the composite powders for a fourth-stage dispersion:

[0132] Crushing stage: 2450rpm operation for 45 seconds, controlling the temperature change rate to ≤2℃ / second, and the fineness reaches 30μm.

[0133] Transition stage: run at 2150 rpm for 65 seconds, maintain a constant temperature of 44°C, and achieve a fineness of 20 μm.

[0134] Fine grinding stage: run at a basic speed of 1750 rpm for 95 seconds until the fineness reaches 15 μm.

[0135] Homogenization stage: 1450 rpm for 130 seconds, until D90 ≤ 10 μm and σ < 0.5 μm.

[0136] The resulting concentrated masterbatch was pumped into the remaining activated matrix in three stages: in the first stage, it was delivered through a static mixer at a flow rate of 4.0 L / min for 30 seconds. In the second stage, it was delivered through a static mixer at a flow rate of 2.7 L / min with 40 kHz ultrasonic assistance for 30 seconds. In the third stage, it was delivered through a static mixer at a flow rate of 1.3 L / min for 30 seconds.

[0137] When coating the functional upper layer, the line speed is reduced by 30% and the coating flow rate is increased by 40%. In the compensation algorithm used, the parameters k are set to 0.15 Gy / μm² and α is set to 0.05 Gy.

[0138] Example 2

[0139] Composite powder: Modified tourmaline powder (average particle size 10μm) and nano-titanium dioxide (average particle size 30nm) are mixed in a weight ratio of 2:1. The particle size ratio is approximately 3:3.

[0140] Gradient functional core layer: The composite powder in the functional upper layer accounts for 40wt% of the total solid content of the coating, and the composite powder in the functional lower layer accounts for 18wt% of the total solid content of the coating, with a concentration difference of 22wt%.

[0141] Wear-resistant and transparent surface layer: 60wt% aliphatic polyurethane acrylate; 25wt% monomer or oligomer; 5wt% photoinitiator. At 45°C, mix the acrylate resin with a dispersant accounting for 1.2% of the resin weight at 1000rpm for 120 seconds to form an activated matrix. Take 30% of the activated matrix and all the composite powders for fourth-order dispersion.

[0142] Crushing stage: Run at 2500 rpm for 40 seconds, and simultaneously control the temperature change rate to ≤ 2°C / second, until the fineness reaches 30μm.

[0143] Transition stage: switch to 2200 rpm and run for 60 seconds, maintaining a constant temperature of 45°C until the fineness reaches 20 μm.

[0144] Fine grinding stage: Run at a basic speed of 1800 rpm for 90 seconds, during which the speed is dynamically adjusted according to the real-time viscosity until the fineness reaches 15 μm.

[0145] Homogenization stage: reduce the speed to 1500 rpm and run for 120 seconds. The process is terminated when D90 ≤ 10 μm and the standard deviation σ < 0.5 μm for 5 consecutive samples.

[0146] The obtained concentrated masterbatch was pumped into the remaining activated matrix and controlled in three stages: in the first stage, it was conveyed through a static mixer at a flow rate of 4.5 L / min for 30 seconds; in the second stage, it was conveyed through a static mixer at a flow rate of 40 kHz and a speed of 3.0 L / min and a speed of 40 kHz ultrasonic assistance was started for 30 seconds; in the third stage, it was conveyed through a static mixer at a speed of 1.5 L / min for 30 seconds.

[0147] When coating the functional upper layer, the line speed is reduced by 40% and the coating flow rate is increased by 50%. In the compensation algorithm used, the parameters k are set to 0.25 Gy / μm² and α is set to 0.08 Gy.

[0148] Example 3

[0149] Composite powder: Modified tourmaline micropowder (average particle size 5μm) and nano-titanium dioxide (average particle size 50nm) are mixed in a weight ratio of 3:1. The particle size ratio is 100 (Note: For ease of comparison, the preferred condition of ≥300 is not strictly adhered to in order to highlight the influence of other parameters).

[0150] Gradient functional core layer: the composite powder in the functional upper layer accounts for 50wt% of the total solid content of the coating; the composite powder in the functional lower layer accounts for 25wt% of the total solid content of the coating; the concentration difference is 25wt%.

[0151] Wear-resistant and transparent surface layer: 50wt% aliphatic polyurethane acrylate; 30wt% monomer or oligomer; 8wt% photoinitiator. At 47°C, mix the acrylate resin with a dispersant accounting for 1.5% of the resin weight at 1200rpm for 110 seconds. At 47°C, mix the acrylate resin with a dispersant accounting for 1.5% of the resin weight at 1200rpm for 110 seconds to form an activated matrix. Take 32% of the activated matrix and all the composite powders for four-stage separation:

[0152] Crushing stage: Run at 2550 rpm for 35 seconds, and simultaneously control the temperature change rate to ≤ 2°C / second, until the fineness reaches 30μm.

[0153] Transition stage: switch to 2250 rpm and run for 55 seconds, maintaining a constant temperature of 46°C until the fineness reaches 20 μm.

[0154] Fine grinding stage: Run at a basic speed of 1850 rpm for 85 seconds, during which the speed is dynamically adjusted according to the real-time viscosity until the fineness reaches 15 μm.

[0155] Homogenization stage: reduce the speed to 1550 rpm and run for 110 seconds. The process is terminated when D90 is ≤ 10 μm and the standard deviation σ is < 0.5 μm for 5 consecutive samples.

[0156] The resulting concentrated masterbatch is pumped into the remaining activated matrix and controlled in three stages:

[0157] In the first stage, the flow rate was 5.0 L / min and sent through the static mixer for 30 seconds. In the second stage, the flow rate was reduced to 3.3 L / min and 40 kHz ultrasonic assistance was started for 30 seconds. In the third stage, the flow rate was further reduced to 1.7 L / min and sent through the static mixer for 30 seconds.

[0158] When coating the functional upper layer, the line speed is reduced by 50% and the coating flow rate is increased by 60%. In the compensation algorithm used, the parameters k are taken as 0.35 Gy / μm² and α is taken as 0.12 Gy.

[0159] Comparative Example 1, a non-gradient structure, uses the same formulation and process as Example 2, but its functional core layer is a single layer with a composite powder concentration of 29 wt% (i.e., the average concentration of the composite powders in the upper and lower layers of Example 2, weighted by their coating thickness). This demonstrates the crucial role of the gradient structure in maintaining functional durability.

[0160] Comparative Example 2 uses a traditional simple dispersion process: The formulation and structure are identical to Example 2, but the material preparation step (S1) is replaced with a traditional single-stage dispersion process: all resin, dispersant, and composite powder are added to the dispersion tank at once and dispersed at 2000 rpm for 30 minutes. This demonstrates the improved performance of the final product achieved through the multi-stage intelligent dispersion process of the present invention.

[0161] Comparative Example 3 adopts a traditional curing process: the formula, structure and preparation process are the same as those of Example 2, but its curing step (S3) adopts traditional fixed-dose curing, that is, no adaptive control system is used, a fixed acceleration voltage and beam intensity are used throughout the process, and no compensation is made for thickness and speed fluctuations.

[0162] The decorative paper samples prepared in Examples 1-3 and Comparative Examples 1-3 were subjected to performance tests under the same conditions. The results are summarized in Table 1 below:

[0163]

[0164] The gradient structure is the key to long-term effectiveness: Comparing Example 2 with Comparative Example 1, the initial concentrations of the two are similar, but after 7 days, the concentration retention rate of Comparative Example 1 drops significantly to 65.2%, while that of Example 2 remains as high as 92.8%. This eloquently demonstrates that the gradient functional core layer structure is the core of achieving sustained release of negative oxygen ions.

[0165] A multi-stage dispersion process is the foundation of high performance: Comparing Example 2 with Comparative Example 2, the initial concentration, light enhancement rate, pencil hardness, and adhesion of Comparative Example 2, which employed simple dispersion, were significantly lower than those of Example 2. This is because simple dispersion failed to effectively break up powder agglomerates, resulting in a large amount of functional powder being trapped within the resin and unable to function, which in turn compromised the coating's physical properties. This demonstrates the critical importance of a multi-stage intelligent dispersion process for fully leveraging material properties and ensuring product physical quality.

[0166] Adaptive curing ensures consistent quality: Comparing Example 2 with Comparative Example 3, the coating thickness uniformity of Comparative Example 3, which used conventional curing, was extremely poor (with a standard deviation as high as 3.56 μm), far inferior to that of Example 2 (0.76 μm). This demonstrates that conventional curing cannot guarantee consistent product quality amidst actual production fluctuations. However, the adaptive curing system, through its multi-factor compensation algorithm, seamlessly overcomes these fluctuations, ensuring highly stable and reliable final product quality.

[0167] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Common changes and substitutions made by those skilled in the art within the scope of the technical solution of the present invention should be included in the protection scope of the present invention.

Claims

1. A decorative paper with a long-lasting release of negative oxygen ions, characterized in that: include: Decorative paper substrate; The composite coating is sequentially stacked on the substrate from the inside out, comprising: Attachment to the bottom layer; Gradient functional core layer; Wear-resistant and transparent surface; The gradient functional core layer is composed of at least one functional lower layer and one functional upper layer, and the concentration of negative oxygen ion material in the functional upper layer is higher than that in the functional lower layer.

2. The decorative paper capable of persistently releasing negative oxygen ions according to claim 1, characterized in that: The functional gradient core layer comprises a composite powder, which includes: Core-shell surface-modified tourmaline powder with an average particle size of 5-15 μm; Photocatalytic nano-titanium dioxide, with an average particle size of 20-50nm; The weight ratio of the modified tourmaline micropowder to nano-titanium dioxide is 1:1 to 3:1, and meets the following conditions: tourmaline particle size / titanium dioxide particle size ≥ 300.

3. The decorative paper capable of persistently releasing negative oxygen ions according to claim 2, characterized in that: The tourmaline powder is modified by coating with silicon dioxide, the coating layer has a thickness of 5-20 nm, and the band gap of the photocatalytic nano titanium dioxide is ≤3.2 eV.

4. The decorative paper capable of persistently releasing negative oxygen ions according to claim 2, characterized in that: In the gradient functional core layer: The composite powder of the functional upper layer accounts for 30-50wt% of the total solid content of the coating; The composite powder of the functional lower layer accounts for 10-25wt% of the total solid content of the coating; The difference in composite powder concentration between the functional upper layer and the functional lower layer is ≥15wt%.

5. The decorative paper capable of persistently releasing negative oxygen ions according to claim 1, characterized in that: The wear-resistant and transparent surface layer is formed by curing a formula comprising the following components: Aliphatic polyurethane acrylate: 50-70wt%; Monomer or oligomer: 20-30wt%; Photoinitiator: 3-8wt%; After curing, a dense cross-linked structure with a pencil hardness of ≥2H is formed, and microscopic channels with an average pore size of 5-50nm exist in the structure.

6. A method for preparing the decorative paper according to any one of claims 1 to 5, characterized in that: Includes the following in order: S1. Material preparation step: preparing a gradient functional core layer coating; S2, precision coating step: coating the adhesive base layer, gradient functional core layer and wear-resistant transparent surface layer on the substrate in sequence; S3, adaptive curing step: electron beam curing is performed under a nitrogen protection environment.

7. The method for preparing decorative paper according to claim 6, wherein step S1 comprises the following steps: Under a constant temperature of 45±2°C, the acrylate resin and 0.8-1.5% of the resin weight of the polyether-modified silicone dispersant were mixed at 800-1200 rpm for 120±10 seconds to form an activated matrix; Step dispersion stage: Take 30±2% of the activated matrix and all the composite powders for four-step high shear dispersion, and perform the following steps in sequence: Crushing stage: Run at 2500±50rpm for 40±5 seconds, and simultaneously control the temperature change rate to ≤2℃ / second, until the fineness reaches 30μm; Transition stage: switch to 2200±50rpm and run for 60±5 seconds, maintaining a constant temperature of 45±1℃ until the fineness reaches 20μm; Fine grinding stage: Run at a basic speed of 1800±50rpm for 90±5 seconds. During this period, the speed is dynamically adjusted according to the real-time viscosity η according to the formula: ； Until the fineness reaches 15μm; Homogenization stage: reduce the speed to 1500±50rpm and run for 120±10 seconds. The process is terminated when D90≤10μm and the standard deviation σ<0.5μm for 5 consecutive samples. Gradient dilution stage: The concentrated masterbatch is pumped into the remaining activated matrix, which is controlled in three stages: Phase 1: Delivery through a static mixer at a flow rate of 4.5 ± 0.5 L / min for 30 seconds; Phase 2: Reduce the speed to 3.0 ± 0.3 L / min and start 40 kHz ultrasound assistance for 30 seconds; The third stage: the speed is reduced to 1.5±0.2L / min and transported through the static mixer for 30 seconds.

8. The method for preparing decorative paper according to claim 7, wherein: In the fine grinding stage, by real-time monitoring of the motor current fluctuation spectrum, when the ratio of the integral value of the power spectrum density in the 5-10kHz frequency band to the integral value of the full frequency band (0-20kHz) is greater than 0.35, the homogenization stage is entered in advance.

9. The method for preparing decorative paper according to claim 7, wherein: Step S2 is implemented using a slit coating head, and the coating thickness is controlled by a closed-loop control system, which includes: An online non-contact thickness sensor located downstream of the coating station; Servo metering pump linked to the sensor; Achieve coating thickness error ≤±2μm, and when coating the functional upper layer: Line speed reduced by 30-50%; Paint flow rate increased by 40-60%; Synchronous start temperature compensation: , in is the coating temperature (℃), is the real-time linear speed (m / min).

10. A control system for curing negative oxygen ion decorative paper, characterized in that include: Environmental control module, maintaining nitrogen protection environment with oxygen concentration <200ppm; The electron beam generating module is configured to output an electron beam with an accelerating voltage of 150-180 kV, a beam current of 10-30 mA, and a linear speed adaptation range of 10-30 m / min; The dose compensation module receives the wet film thickness signal T and the line speed signal v in real time, and outputs the electron beam parameter adjustment signal through the compensation algorithm; Energy coupling module, real-time acquisition of cumulative energy density from the dispersion process data; The compensation formula is: ； Among them, k=0.15-0.35 Gy / μm², α=0.05-0.12 Gy; described Calculated by the following formula: ； Among them: i=1, 2, 3, 4 correspond to the crushing stage, transition stage, fine grinding stage, and homogenization stage respectively; is the slurry density at each stage (kg / m³); is the actual speed at each stage (rpm); is the duration (s); is the stage correction coefficient.

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