A surface treatment process for office furniture panels

Abstract

The present invention relates to the field of surface treatment technology, and specifically to a surface treatment process for office furniture panels, comprising the following steps: A. selecting a primer with a solid content of 40-50%, the primer containing nano-scale fillers, and using a curtain coating machine for curtain coating in a coating workshop. The primer is filtered through a 100-150 mesh filter in a coating pipeline connected to the curtain coating machine. The coating pressure is 0.3-0.5 MPa, and the substrate conveying speed is 6-8 m / min. B. After curtain coating, the substrate enters a leveling zone for leveling for 30-60 seconds, and the flow Wind speed in flat area ≤ 0.5m / s; C. UV curing is performed using a UV curing machine with curing parameters of wavelength 365nm, energy 800-1200mJ / cm², and curing time 10-15 seconds. The coating is cyclically heated to 25-30°C in step A. The purpose of the present invention is to solve the problem that the thickener in the water-based paint is prone to form flocculent agglomerates in the existing curtain coating machine in the surface treatment process of office furniture panels, and the undispersed matting powder particles in the UV coating are prone to gradual sedimentation during pumping, which easily leads to nozzle clogging.

Description

Technical Field

[0001] The invention relates to the technical field of surface treatment, in particular to a surface treatment process for office furniture panels. Background Art

[0002] The surface of office furniture panels is coated and cured in multiple layers to form a protective layer, achieving a customized gloss effect from matte to glossy. It is wear-resistant, scratch-resistant, stain-resistant, corrosion-resistant and moisture-proof. It adopts a water-based environmentally friendly formula with an E0-level environmentally friendly substrate to meet the requirements of anti-yellowing durability, environmental protection standards and high-end texture. It is suitable for open office areas, conference rooms, executive offices and other scenes. While ensuring easy cleaning and long life, it provides tactile finishes such as mirror and frosted to upgrade the aesthetic experience of office space.

[0003] Among them, curtain coating is used as the core coating technology. The primer layer seals the pores of the substrate, and the topcoat layer shapes the surface texture to achieve uniform coverage of the coating. The water-based UV coating is evenly coated on the surface of the E0-grade substrate through a curtain coating machine to form a wet film of primer and topcoat, which is then formed into a paint film after UV curing.

[0004] In the existing curtain coating machine's surface treatment process for office furniture panels, the thickener in the water-based paint tends to form flocculent agglomerates, and the undispersed matting powder particles in the UV coating tend to gradually settle during pumping. When there are particles in the coating that exceed 1 / 3 of the nozzle aperture, it directly causes physical blockage, resulting in a sudden increase in local pressure drop.

[0005] The blockage of the coating machine nozzle will lead to a decline in coating quality, resulting in defects such as uneven coating thickness, surface bumps, and orange peel texture, while also causing reduced production efficiency and increased maintenance costs. Summary of the Invention

[0006] The purpose of the present invention is to provide a surface treatment process for office furniture panels to solve the problem that in the existing curtain coating machine, the thickener in the water-based paint easily forms flocculent agglomerates, and the undispersed matting powder particles in the UV coating easily gradually settle during pumping, which easily leads to nozzle clogging.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] A surface treatment process for office furniture panels, the specific steps are as follows:

[0009] A. The coating is a primer with a solid content of 40-50%, which contains nano-scale fillers and is applied in a coating workshop using a curtain coating machine. The primer is filtered through a 100-150 mesh filter in a coating pipeline connected to the curtain coating machine. The coating pressure is 0.3-0.5 MPa and the substrate conveying speed is 6-8 m / min.

[0010] B. After curtain coating, enter the leveling zone and level for 30-60 seconds. The wind speed in the leveling zone is ≤0.5m / s.

[0011] C. Use a UV curing machine for UV curing. The curing parameters are wavelength 365nm, energy 800-1200mJ / cm², and curing time 10-15 seconds.

[0012] Preferably, in step A, the coating flow rate is adjusted to 300-500 ml / min by a gear pump, and the nozzle is 15-20 mm away from the substrate surface.

[0013] Preferably, in step A, the coating is cyclically heated to 25-30°C.

[0014] Preferably, an online particle detection sensor is installed on the paint pipe before the filter to detect the concentration of 0.1-100 μm particles in the paint. When the particle concentration is greater than 1000 particles / ml, the sensor sends the detected signal to the controller to trigger the alarm device.

[0015] Preferably, the paint pipeline includes a main filter channel and a spare filter channel, both of which are equipped with 100-150 mesh filters. An electric switching valve for switching the main filter channel and the spare filter channel is installed on the paint pipeline. When the particle concentration is greater than 1000 particles / ml, the sensor sends the detected signal to the controller to execute the control logic of automatically closing the main filter channel electric valve and opening the spare filter channel electric switching valve.

[0016] Preferably, the spare filter channel is equipped with an independent circulation pump, and the spare filter channel is pre-filled with primer before switching.

[0017] Preferably, the alarm device includes a red warning light and a buzzer, and the alarm continues until manually reset.

[0018] Preferably, the temperature in the coating workshop is controlled at 21-25° C., and the humidity is controlled at 45-55% RH.

[0019] Preferably, the interval time from curtain coating to UV curing is ≤ 1 minute.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] The filter can intercept large particles of impurities in the paint, preventing these impurities from entering the nozzle and causing blockage, ensuring a stable and continuous coating process. When it detects that a large number of particles are intercepted in the main channel filter, the system will automatically switch to the backup filter channel to continue production, and at the same time remind manual cleaning of the main channel filter. The problem can be handled without shutting down the machine, ensuring that even if the main filter needs maintenance, the production line can continue to operate, greatly reducing downtime caused by equipment failure. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Schematic diagram of the local structure of the filtration channel of the present invention;

[0023] Figure 2 A flow chart of the process for forming a paint film according to the present invention;

[0024] Figure 3 Flowchart of the coating curtain process of the present invention.

[0025] In the figure: 1. Main filter channel; 2. Backup filter channel; 3. Circulation pump; 4. Main storage tank; 5. Electric switching valve. DETAILED DESCRIPTION

[0026] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0027] See also Figure 1 , the present invention provides a technical solution.

[0028] A surface treatment process for office furniture panels, characterized by:

[0029] A. Use E0 grade environmentally friendly boards with formaldehyde emission ≤ 0.05mg / m³, remove surface burrs through mechanical sanding, use 80-120 grit sandpaper to improve flatness, and use vacuum adsorption or compressed air to remove surface dust to ensure that no impurities remain.

[0030] B. The coating uses a water-based UV sealing primer with a solid content of 40-50%, containing nano-scale fillers, such as nano-silica fillers, with strong penetration. A curtain coating machine is used in the coating workshop for uniform curtain coating. A 0.15mm slit nozzle and a coating pressure of 0.3-0.5MPa are used. The film thickness is controlled at 15-20μm. After curtain coating, it enters the leveling zone and stands for 30-60 seconds to allow the coating to level naturally. The wind speed is ≤0.5m / s. Ensure that the substrate pore sealing rate is ≥98% (microscope detection) and the orange peel index is ≤3.0 (BYK instrument measurement).

[0031] In step B, adjust the parallelism of the curtain machine scraper and the substrate conveyor line to an error of ≤0.1mm. Use a laser calibrator to calibrate daily to ensure that the curtain covers vertically and evenly. Use compressed air to clean the nozzle at a pressure of 0.4-0.6MPa to avoid paint splashing or curtain breakage. The substrate conveying speed is controlled at 6-8m / min (fine-tuned according to film thickness requirements). The curtain machine nozzle is 15-20mm away from the substrate surface to ensure that the curtain is stable and drip-free. The flow rate is adjusted to 300-500ml / min by using a gear pump to match the film thickness requirements (15-20μm wet film). The temperature and humidity in the coating workshop are stabilized at 23±2℃ and 50±5%RH to avoid fluctuations in paint viscosity and abnormal leveling.

[0032] In step B, the solid content of the water-based UV sealing primer is 40-50% (detected by a refractometer) and the viscosity is 25±5cps (25°C, Brookfield viscometer). To ensure curtain stability, filter the water-based UV sealing primer through a 100-150 mesh filter to remove foreign particles and prevent nozzle clogging. The paint is circulated and heated to 25-30°C to reduce viscosity and improve fluidity. The paint temperature close to room temperature reduces the temperature difference with the board, reduces coating shrinkage stress, and enhances adhesion.

[0033] In step B, align the edge of the sheet with the conveyor line to avoid coating deviation (error ≤ 1mm). Start the coating curtain machine, and the coating will evenly cover the substrate surface in a continuous curtain, forming a 15-20μm wet film. Observe the integrity of the curtain. If the curtain is broken or the thickness is uneven, stop the machine immediately and check the nozzle or coating flow problem.

[0034] In step B, after curtain coating, let it stand for 30-60 seconds to allow gravity to level the coating and eliminate curtain marks. Keep the leveling area in a windless environment to avoid airflow interference causing orange peel or shrinkage. After curtain coating, enter the UV curing stage immediately (interval ≤ 1 minute) to avoid wet film contamination or solvent volatilization affecting the curing effect.

[0035] C. Use a high-pressure mercury lamp UV curing machine (wavelength 365nm, energy 800-1200mJ / cm²), with a curing time of 10-15 seconds, to quickly crosslink the primer into a film with a hardness of more than 2H. UV curing does not require a traditional drying process, saving about 40% of energy consumption and reducing VOC emissions, meeting green production requirements.

[0036] Install an online particle detection sensor, including a laser scattering sensor, on the paint pipeline before the filter to detect the concentration of 0.1-100μm particles in the paint in real time;

[0037] Pressure sensing modules are installed at the front and rear ends of the filter to detect the filter pressure difference ΔP;

[0038] The paint pipeline includes a main filter channel 1 and a backup filter channel 2, both equipped with 100-150 mesh filters. The main and backup channels both use 100-150 mesh filters. The filtration efficiency remains consistent after switching, ensuring that there is no difference in the coating appearance.

[0039] The paint pipeline is equipped with an electric switching valve 5 for switching between the main filter channel 1 and the backup filter channel 2. The response time is ≤ 2 seconds, which avoids the loss of production capacity caused by the need to stop and clean the traditional single-channel filter. The electric switching valve 5 has two branch ports connected to the main filter channel 1 and the backup filter channel 2 respectively, and the main port is connected to the main channel of the paint pipeline.

[0040] When the laser scattering particle sensor detects a particle concentration in the paint greater than 1000 particles / ml, or when the pressure sensor detects a pressure differential (ΔP) greater than 0.2 MPa across the filter, the sensor transmits an analog signal to the programmable logic controller (PLC). Upon receiving the signal, the PLC, if the trigger condition is met, outputs a control signal to trigger an audible and visual alarm, simultaneously executing the control logic to automatically close the electric valve in main filter channel 1 and open the electric valve in backup filter channel 2. After the switch is complete, the PLC records the switch time and the triggering reason (e.g., excessive particle concentration or excessive pressure differential) in its internal memory.

[0041] The laser scattering sensor has an accuracy of ±5% and a detection flow range of 0.1-1 L / min. The filter is made of 316L stainless steel and the surface is electrochemically polished.

[0042] The standby channel is equipped with an independent circulation pump 3, which pre-fills the standby filter channel 2 with primer before switching, so that the standby filter channel 2 is automatically pre-filled to the system pressure, ensuring that the standby system can quickly and smoothly take over the work of the main system when switching, avoiding production abnormalities caused by pressure fluctuations or fluid interruptions. The circulation pump 3 and the electric switching valve 5 are both connected to the main storage tank 4. The circulation pump 3 and the electric switching valve 5 are connected to the same primer supply source main storage tank 4, rather than their own separate storage containers, to reduce the risk of contamination in the intermediate links.

[0043] The controller adopts Siemens S7-1200 PLC; the human-machine interface (HMI) displays the particle concentration curve and switching history records in real time.

[0044] When the main filter channel 1 and the spare filter channel 2 are switched, the residual paint is introduced into the waste tank. The upper and lower ports of the main filter channel 1 and the spare filter channel 2 are detachably connected to the paint pipeline. When the main filter channel 1 and the spare filter channel 2 are switched, the upper and lower ports are disconnected from the paint pipeline to clean the residual paint inside, or replace the filter screen. The matching flanges can be fastened by bolts, and a sealing gasket is sandwiched in the middle for detachable connection. It can also be composed of two semi-circular ring clamps and a sealing gasket, which are fastened by bolts to form a detachable connection structure. Disassembly and assembly are convenient, and only two bolts need to be loosened.

[0045] The alarm device includes a red warning light and a buzzer (≥85dB). It will continue to alarm until manually reset. It will continue to alarm until manually reset, forcing operators to investigate the cause of the excessive particle size (such as raw material contamination, filter damage, etc.) to prevent the problem from recurring.

[0046] The specific solution is as follows: install the online particle detection sensor on the paint pipe in front of the filter to ensure that the sensor can accurately detect the paint particles entering the filter, install the alarm device near the operation panel of the curtain machine, install the PLC and HMI in the control cabinet, and connect the signal lines and power lines of the sensor, alarm device, switching valve and other equipment.

[0047] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A surface treatment process for office furniture panels, characterized in that: The specific steps are as follows: A. The coating is a primer with a solid content of 40-50%, which contains nano-scale fillers and is applied in a coating workshop using a curtain coating machine. The primer is filtered through a 100-150 mesh filter in a coating pipeline connected to the curtain coating machine. The coating pressure is 0.3-0.5 MPa and the substrate conveying speed is 6-8 m / min. B. After curtain coating, enter the leveling zone and level for 30-60 seconds. The wind speed in the leveling zone is ≤0.5m / s. C. Use a UV curing machine for UV curing, the curing parameters are wavelength 365nm, energy 800-1200mJ / cm², and curing time 10-15 seconds; An online particle detection sensor is installed on the paint pipe in front of the filter to detect the concentration of 0.1-100μm particles in the paint. When the particle concentration is greater than 1000 particles / ml, the sensor sends the detected signal to the controller to trigger the alarm device; The paint pipeline includes a main filter channel and a backup filter channel, both of which are equipped with 100-150 mesh filters. An electric switching valve for switching between the main filter channel and the backup filter channel is installed on the paint pipeline. When the particle concentration is greater than 1000 particles / ml, the sensor sends the detected signal to the controller to execute the control logic of automatically closing the main filter channel electric valve and opening the backup filter channel electric switching valve; The standby filter channel is equipped with an independent circulation pump, and the standby filter channel is pre-filled with primer before switching; When the main filter channel 1 and the backup filter channel 2 are switched, the residual paint is introduced into the waste tank. The upper and lower ports of the main filter channel 1 and the backup filter channel 2 are detachably connected to the paint pipeline. When the main filter channel 1 and the backup filter channel 2 are switched, the upper and lower ports are disconnected from the paint pipeline to clean the residual paint inside.

2. The surface treatment process for office furniture panels according to claim 1, characterized in that: In step A, the coating flow rate is adjusted to 300-500 ml / min by a gear pump, and the nozzle is 15-20 mm away from the substrate surface.

3. The surface treatment process for office furniture panels according to claim 1, characterized in that: In step A, the coating is heated in a circulation manner to 25-30°C.

4. The surface treatment process for office furniture panels according to claim 1, characterized in that: The alarm device includes a red warning light and a buzzer, which will continue to alarm until manually reset.

5. The surface treatment process for office furniture panels according to claim 1, characterized in that: The temperature in the coating workshop is controlled at 21-25°C and the humidity is controlled at 45-55% RH.

6. The surface treatment process for office furniture panels according to claim 1, characterized in that: The interval time from curtain coating to UV curing is ≤1 minute.

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