Colorful laminated board production process based on ultrahigh pressure dipping coloring

Abstract

The invention discloses a color laminated board production process based on ultrahigh pressure dipping coloring, and belongs to the technical field of artificial board manufacturing. Firstly, high-temperature heat treatment is conducted on a wood veneer, and the pore structure of the wood veneer is optimized; then preparing a functionalized colored resin adhesive containing nanoscale coloring; the key step adopts a synergistic ultrahigh-pressure impregnation technology, so that resin deeply permeates into a wood cell wall layer, and coloring and reinforcing are integrated; and finally, the dipped wet-state veneer is subjected to one-time forming in a directional assembly and hot pressing process. Traditional dyeing and intermediate drying links are thoroughly omitted, dyeing wastewater is completely eradicated from the source, the process is remarkably shortened, and energy consumption is reduced. The obtained product has excellent physical and mechanical properties, extremely high dimensional stability and lasting color weather resistance, and is suitable for manufacturing high-end outdoor building materials and furniture.

Description

Technical Field

[0001] This invention belongs to the field of engineered wood manufacturing technology, specifically, it relates to a production process for colored laminates based on ultra-high pressure impregnation and coloring. Background Technology

[0002] Colored laminate, as a type of engineered wood material that combines decorative and practical features, is widely used in high-end furniture manufacturing, outdoor landscaping materials, interior decoration, and public space partitions. With rising consumer demand and increasingly stringent environmental policies, market requirements for colored laminate have evolved from simple aesthetic enhancements to a multi-dimensional upgrade encompassing environmental performance, durability, and functionality. This is especially true in outdoor applications, where higher demands are placed on the product's weather resistance, fade resistance, and waterproofing / moisture resistance.

[0003] The traditional production of colored laminates has long relied on a "dye-then-resin impregnation" process. This involves first dyeing the wood veneer, followed by drying, resin impregnation, and another drying, ultimately achieving the finished product through hot pressing. This model has gradually revealed numerous technical and environmental bottlenecks over time, becoming a significant obstacle to the industry's sustainable development. Environmentally, the large amounts of organic dyes and chemical auxiliaries used in the dyeing process result in wastewater containing high concentrations of recalcitrant colored substances and harmful chemicals. Treatment is difficult and costly, and it easily causes persistent pollution to water bodies. Simultaneously, the drying stage after resin impregnation releases large amounts of volatile organic compounds (VOCs), exacerbating air pollution and posing a threat to the health of workers on the production floor, making it difficult to meet increasingly stringent environmental regulations and green manufacturing requirements.

[0004] From a process efficiency perspective, traditional methods are lengthy and energy-intensive. After dyeing, the veneer must be thoroughly dried to remove moisture before subsequent resin impregnation. After impregnation, it needs to be dried again to remove solvent and moisture from the resin. This repeated "wet-dry" conversion leads to extended production cycles, high equipment occupancy, and significant heat energy consumption for each drying cycle, resulting in persistently high overall energy consumption. Furthermore, multiple heat treatments can cause changes in internal wood stress, increasing the risk of veneer warping and cracking, thus affecting yield and material utilization.

[0005] In terms of product performance, traditional dyeing processes typically rely on penetrants or chemical modifications to allow dyes to penetrate the shallow surface of the wood. This process often damages the natural fiber structure of the wood, reducing its mechanical strength. Because the dyes only adhere to the fiber surface or shallow pores and fail to form a strong bond with the subsequently impregnated resin, they are prone to fading and peeling due to ultraviolet radiation, temperature and humidity changes, or friction during long-term use, affecting aesthetics and durability.

[0006] In summary, the traditional color laminate production process has multiple shortcomings in terms of environmental protection, production efficiency, and product performance, which has become a technical problem that urgently needs to be solved in the industry. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of the prior art and provide a color laminate production process based on ultra-high pressure impregnation and coloring.

[0008] The objective of this invention can be achieved through the following technical solutions: A color laminate production process based on ultra-high pressure impregnation coloring includes the following steps: Step 1: Rotary cut or plan the logs to obtain veneers; Step 2: Place the veneer in a heat treatment kiln and heat treat it under a nitrogen atmosphere to reduce the moisture content of the veneer to below 5% and destroy the hydrophilic groups of the wood to obtain heat-treated veneer. Step 3: Mix the resin, curing agent, color filler and functional additives evenly in a high-speed disperser, and remove air bubbles through a vacuum degassing device to obtain colored resin adhesive; Step 4: Place the heat-treated veneer in a high-pressure impregnation tank, evacuate to -0.08 to -0.1 MPa, maintain for 15-25 minutes, then inject colored resin glue into the tank under vacuum. After the colored resin glue completely impregnates the veneer, release the vacuum and start the pressurization system to perform ultra-high pressure impregnation to obtain the impregnated veneer. Step 5: After the impregnated veneers are stacked and assembled, they are sent into a hot press, heated in stages to 150-170℃, and pressure is applied to press them into shape in one go. After cooling and demolding, a colored laminate based on ultra-high pressure impregnation and coloring is obtained.

[0009] As a further technical solution, the thickness of the single board is 0.5-3.0mm.

[0010] As a further technical solution, the heat treatment temperature is 220-240℃ and the time is 2-3h; preferably, the heat treatment temperature is 230℃.

[0011] As a further technical solution, the weight ratio of the resin, curing agent, color filler and functional additive is 100:8-12:12-18:5-10.

[0012] As a further technical solution, the resin is one of phenolic resin, melamine resin and epoxy resin.

[0013] As a further technical solution, the color filler is a nano-sized inorganic pigment.

[0014] As a further technical solution, the functional additive is a mixture of ultraviolet absorber, light stabilizer and nano-silica aerogel powder in a weight ratio of 2:2:1.

[0015] As a further technical solution, the high-speed disperser has a rotation speed of 800-1000 rpm and a mixing time of 20-40 min.

[0016] As a further technical solution, the pressure of the ultra-high pressure impregnation is 8-12 MPa, and the time is 40-60 min; preferably, the pressure of the ultra-high pressure impregnation is 10 MPa.

[0017] As a further technical solution, the applied pressure is 8-12 MPa.

[0018] This invention utilizes high-temperature heat treatment to protect the strength of the cellulose skeleton while controlling pyrolysis to remove some hemicellulose and lignin for recombination, achieving deep dehydration and preventing defects caused by subsequent moisture evaporation. It also reduces hydrophilic groups, improving dimensional stability and corrosion resistance. Most importantly, it creates and expands a micro / nano pore network at the cell wall level, facilitating subsequent ultra-high pressure deep impregnation. The use of nanoscale pigments ensures vibrant, stable, and easily penetrating colors. Added functional additives enhance the light aging resistance and dimensional stability of the final product. Ultra-high pressure impregnation completely eliminates air from the wood pores, preventing it from hindering resin entry and pushing the resin into tiny pores inaccessible by conventional pressure, thus improving the impregnation effect. Direct hot pressing of wet veneer eliminates the need for a separate drying process, improving efficiency.

[0019] The beneficial effects of this invention are: The production process of this invention integrates high-temperature heat treatment, ultra-high pressure impregnation, and stepped wet pressing, resulting in the following advantages: 1. Completely eliminates dye-containing wastewater generated by traditional dyeing processes, and significantly reduces VOC emissions through integrated process and resin system optimization; 2. Eliminating intermediate drying processes and wastewater treatment costs shortens the production cycle and improves enterprise production efficiency and economic benefits; 3. The resulting laminate has strong mechanical properties and weather resistance, making it suitable for long-term outdoor use. Furthermore, the wood fibers and adhesive are deeply bonded together, resulting in strong interfacial bonding and a stable structure. Detailed Implementation

[0020] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Example 1 A color laminate production process based on ultra-high pressure impregnation coloring includes the following steps: Step 1: Rotary cut the eucalyptus wood to obtain veneers with a thickness of 1.5mm; Step 2: Place the veneer in a heat treatment kiln and heat it to 230°C for 2.5 hours under a nitrogen atmosphere to reduce the moisture content of the veneer to 4% and obtain the heat-treated veneer. Step 3: Add 100 parts of phenolic resin, 10 parts of hexamethylenetetramine, 15 parts of nano iron oxide red and 5 parts of functional additives (2 parts of Tinuvin 1130, 2 parts of Tinuvin 770 and 1 part of nano silica aerogel powder) to a high-speed disperser (speed of 800 rpm) and mix for 20-40 minutes. Remove air bubbles by vacuum degassing equipment to obtain colored resin glue. Step 4: Place the heat-treated veneer in a high-pressure impregnation tank, evacuate to -0.09MPa and maintain for 20 minutes. Then, under vacuum, inject colored resin into the tank. Once the colored resin has completely submerged the veneer, release the vacuum and start the pressurization system. Impregnate at 10MPa for 50 minutes to obtain the impregnated veneer. Step 5: After stacking 8 layers of impregnated veneer into a blank, put it into a hot press, first heat it to 120℃, keep it at that temperature for 10 minutes, then heat it to 160℃ and apply a pressure of 10MPa, hot press for 20 minutes, press it into shape in one step, cool it, demold it, and you will get a colored laminate based on ultra-high pressure impregnation coloring.

[0022] Example 2 A color laminate production process based on ultra-high pressure impregnation coloring includes the following steps: Step 1: Plane the eucalyptus wood to obtain veneers with a thickness of 1.5mm; Step 2: Place the veneer in a heat treatment kiln and heat it to 240°C for 3 hours under a nitrogen atmosphere to reduce the moisture content of the veneer to 4% and obtain the heat-treated veneer. Step 3: Add 100 parts of phenolic resin, 12 parts of hexamethylenetetramine, 18 parts of nano iron oxide red and 5 parts of functional additives (2 parts of Tinuvin 1130, 2 parts of Tinuvin 770 and 1 part of nano silica aerogel powder) to a high-speed disperser (1000 rpm) and mix for 40 minutes. Remove air bubbles by vacuum degassing equipment to obtain colored resin glue. Step 4: Place the heat-treated veneer in a high-pressure impregnation tank, evacuate to -0.1MPa and maintain for 25 minutes. Then, under vacuum, inject colored resin into the tank. Once the colored resin has completely submerged the veneer, release the vacuum and start the pressurization system. Impregnate at 12MPa for 60 minutes to obtain the impregnated veneer. Step 5: After stacking 8 layers of impregnated veneer into a blank, put it into a hot press. First, heat it to 120°C and hold it for 10 minutes. Then, heat it to 170°C and apply a pressure of 12MPa. Press it for 20 minutes to form it in one press. After cooling and demolding, you will get a colored laminate based on ultra-high pressure impregnation coloring.

[0023] Comparative Example 1 The traditional dyeing, drying, and then resin impregnation process is as follows: Step 1: Plane the eucalyptus wood to obtain veneers with a thickness of 1.5mm; Step 2: Prepare a 5% (w / w) solution of Acid Red GR organic dye, immerse the veneer in the dye solution, and dye at a constant temperature of 60℃ for 30 minutes; then dry it in an oven at 105℃ for 2 hours to obtain the dyed veneer. Step 3: Place the dyed veneer in an atmospheric pressure impregnation tank (0.1 MPa, normal atmospheric pressure), inject 100 parts of phenolic resin and 10 parts of hexamethylenetetramine mixture into the tank, impregnate for 30 minutes, remove and dry again in an oven at 105℃ for 2 hours to obtain impregnated veneer. Step 4: Consistent with the method in the embodiment, after stacking 8 layers of impregnated veneer into a blank, it is sent into a hot press. First, the temperature is raised to 120°C and held for 10 minutes. Then, the temperature is raised to 160°C and a pressure of 10 MPa is applied. The hot press is carried out for 20 minutes and formed in one press. After cooling and demolding, a traditional process colored laminate is obtained.

[0024] The following performance tests were conducted on Example 1 and Comparative Example 1: The color change ΔE (weather resistance) was measured according to the GB / T 16422.3-2022 standard. The 24-hour water absorption swelling rate (dimensional stability) was determined according to GB / T 17657-2013 standard. Formaldehyde emission was determined and rated using the climate chamber method; The measurement results are shown in Table 1: Table 1

[0025] As can be seen from the test results in Table 1, the colored laminate produced by the present invention has better weather resistance, dimensional stability and environmental friendliness compared with the traditional method. Therefore, the present invention has important application value in the field of artificial board manufacturing technology.

[0026] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

Claims

1. A production process of a color laminated board based on super high pressure impregnation coloring, characterized by, The method comprises the following steps: Step 1, rotary cutting or planing the raw wood to obtain veneers; Step 2, placing the veneers in a heat treatment kiln for heat treatment under a nitrogen atmosphere to obtain heat-treated veneers; Step 3, mixing resin, curing agent, color filler and functional additives in a high-speed disperser, vacuum degassing to obtain colored resin glue; Step 4, placing the heat-treated veneers in a high-pressure impregnation tank, vacuumizing to -0.08 to -0.1 MPa for 15-25 min, then injecting the colored resin glue into the tank under vacuum, and after the colored resin glue completely immerses the veneers, releasing the vacuum for ultrahigh-pressure impregnation to obtain impregnated veneers; Step 5, stacking the impregnated veneers to form a stack, and then feeding the stack into a hot press, and stepwise heating to 150-170℃ and applying pressure for one-time compression molding, cooling, demolding to obtain colored laminated boards based on ultrahigh-pressure impregnation coloring.

2. The production process of a color laminated sheet based on super high pressure impregnation coloring according to claim 1, characterized in that, The thickness of the veneers is 0.5-3.0 mm.

3. The production process of a color laminated sheet based on super high pressure impregnation coloring according to claim 1, characterized in that, The heat treatment temperature is 220-240℃, and the time is 2-3 h.

4. The production process of a color laminated sheet based on super high pressure impregnation coloring according to claim 1, characterized in that, The weight ratio of the resin, curing agent, color filler and functional additives is 100:8-12:12-18:5-10.

5. The production process of a color laminated sheet based on super high pressure impregnation coloring according to claim 1, characterized in that, The resin is one of phenolic resin, melamine resin and epoxy resin.

6. The production process of a color laminated sheet based on super high pressure impregnation coloring according to claim 1, characterized in that, The color filler is a nanoscale inorganic pigment.

7. The production process of a color laminated sheet based on super high pressure impregnation coloring according to claim 1, characterized in that, The functional additives are ultraviolet absorbers, light stabilizers and nanosilica aerogel powders compounded at a weight ratio of 2:2:

1.

8. The production process of a color laminated sheet based on super high pressure impregnation coloring according to claim 1, characterized in that, The ultrahigh-pressure impregnation pressure is 8-12 MPa, and the time is 40-60 min.

9. The production process of a color laminated sheet based on super high pressure impregnation coloring according to claim 1, characterized in that, The applied pressure is 8-12 MPa.

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