Preparation method of antibacterial biomass composite floor

Abstract

The invention belongs to the technical field of antibacterial biomass floor processing, and particularly relates to a preparation method of an antibacterial biomass composite floor, which mainly comprises the following steps: S1, raw material pretreatment: processing sawdust into primarily processed wood flour, and processing crop straws into crop straw fragments; the method comprises the following steps of: compounding and forming: coating urea resin on a wood base material and a sheet to form a wood base plate and a sheet plate, assembling by adopting a single wood base plate or a single sheet plate or a wood base plate and sheet plate mixed and overlapped form, and finally cutting into a plate blank, so that the defects in the prior art are overcome, renewable resources such as wood, crop straws and the like are used as core base materials; a natural or synthetic antibacterial agent is uniformly dispersed in a base material or fixed on the surface of the base material by means of physical modification, chemical treatment or composite processing and the like, so that the floor is endowed with efficient and lasting antibacterial performance.

Description

Technical Field

[0001] The present invention belongs to the technical field of antibacterial biomass floor processing, and particularly relates to a preparation method of an antibacterial biomass composite floor. Background Art

[0002] The current commercially available antibacterial floor technologies mainly have the following four bottlenecks: a. The antibacterial performance decays rapidly and the long-term effectiveness is insufficient Traditional antibacterial floors mostly adopt the process of spraying antibacterial agents on the surface (such as chlorine-containing organic antibacterial agents), but there are two major defects: mainly physical attachment: the binding force between the antibacterial agent and the substrate is weak, and it is easy to fall off after daily friction and cleaning, resulting in a 40%-60% decrease in the antibacterial rate within 3 months (tested according to the GB / T21352-2020 standard), single antibacterial mechanism: relying on the immediate release of metal ions such as nano silver for sterilization, lacking a slow-release system, unable to cope with the microbial adaptive evolution during long-term use, and the drug resistance of some strains (such as Escherichia coli O157:H7) increases by 30% after 6 months b. The imbalance between the environmental protection and functionality of the substrate There are generally two major contradictions in the existing technologies: insufficient functions of natural substrates: solid wood floors are environmentally friendly but their antibacterial ability depends on later spraying, and they are prone to moisture absorption and deformation (swelling and shrinkage of 0.3mm / m occurs when the moisture content fluctuates by ±2%); pollution problems of artificial boards: traditional wood-plastic composite floors (WPC) use petroleum-based resins such as polypropylene, and when the addition amount ≥ 40%, VOCs are released (formaldehyde release amount ≥ 1.5mg / L, exceeding the E0 standard), and the utilization rate of agricultural waste such as rice husks and straws is less than 30%. The fiber modification technology is backward, resulting in weak interfacial bonding force (shear strength < 5MPa).

[0003] c. The contradiction between the uniform dispersion and safety of antibacterial agents Nano antibacterial agents (such as nano zinc oxide with a particle size > 100nm) are prone to agglomeration to form hot spot areas, resulting in: local toxicity risk: when the nano silver ion concentration > 50ppm, it significantly inhibits the survival rate of human epidermal cells (HaCaT) (inhibition rate > 20%, ISO10993-5 standard); mechanical property deterioration: when the addition amount of unmodified nano particles (such as TiO2) > 2%, the static bending strength of the composite material decreases by 15%-20% (due to stress concentration at the fiber-resin interface).

[0004] d. Single environmental adaptability and insufficient function extensibility Traditional technologies are limited to single antibacterial functions and are significantly restricted by the environment: photocatalytic antibacterial relies on ultraviolet light: commercially available TiO2-based antibacterial floors are only effective under ultraviolet irradiation (λ = 254 nm), and the sterilization efficiency decreases by more than 60% in a natural light environment; they fail in humid environments: in scenarios such as hospital wards and kitchens with a relative humidity > 80%, natural antibacterial agents such as chitosan are prone to moisture absorption and degradation, resulting in a sharp drop in the antibacterial rate (a 35% drop within 24 hours).

[0005] Therefore, it is necessary to develop a new antibacterial biomass floor to meet market demands. Summary of the Invention

[0006] The purpose of the present invention is to provide a method for preparing an antibacterial biomass composite floor, which overcomes the deficiencies of the prior art. Aiming at the technical bottlenecks of existing antibacterial floors in terms of long-term effectiveness, environmental friendliness, functional adaptability, and safety, this solution forms a technological breakthrough of "substrate functionalization - antibacterial persistence - application scenario adaptation" through biomass substrate modification technology, composite antibacterial system construction, and multi-dimensional performance optimization. Its core value lies in breaking through the traditional "terminal antibacterial" thinking, achieving a deep integration of antibacterial functions and biomass characteristics from the source of material design, providing a sustainable technical solution for solving microbial pollution problems in the public health field, having a significant role in promoting industrial upgrading and social application value. By using renewable resources such as wood and crop straw as the core substrates, through physical modification, chemical treatment, or composite processing, natural or synthetic antibacterial agents are uniformly dispersed inside the substrates or fixed on the surface, thereby endowing the floor with efficient and long-lasting antibacterial performance. Its advantages lie in combining the renewable and low-carbon environmental protection characteristics of biomass materials with the hygienic safety of antibacterial functions, and are applicable to places with high environmental hygiene requirements such as hospitals, schools, kindergartens, and families.

[0007] To solve the above problems, the technical solutions adopted by the present invention are as follows: A method for preparing an antibacterial biomass composite floor, comprising the following steps: S1: Raw material pretreatment: Pass the wood chips through a 100-mesh sieve, add the silane coupling agent KH570 for treatment with a coupling agent concentration of 1%, then soak in an ethanol solution for 2 hours, and finally dry at 100 °C for 2 hours to obtain wood powder. Crush the crop straw through an 80-mesh sieve, treat it with a 1.5% NaOH solution for 24 hours, and rinse with clean water until neutral to obtain the crushed crop straw for standby; S2: Antibacterial agent loading: Prepare a 0.08 mol / L AgNO3 solution, add the wood powder or crushed crop straw and disperse it ultrasonically for 40 minutes, then dropwise add a 1 mol / L ascorbic acid solution for a reduction reaction at room temperature for 1.5 hours, and finally wash with clean water 3 times. The initially processed wood powder and crop straw powder are dried at 105 °C and then ground to obtain the initially processed wood powder and crop straw powder for standby; S3: Preparation of photocatalytic layer: 5 g of nano-TiO₂ was dispersed in 50 g of acrylate emulsion, and then 0.5 g of dispersant was added and ultrasonically dispersed for 30 min to obtain a photocatalytic coating; S4: Co-extrusion of wood board: 60 parts of pre-processed wood powder, 35 parts of high-density polyethylene (HDPE), and 5 parts of compatibilizer (PE-g-MAH) were premixed, and then extruded into a wood substrate through a twin-screw extruder. The parameters of the twin-screw extruder were a temperature of 180 - 200 °C and a screw speed of 200 rpm; S5: Preparation of microcapsules: 5 g of chitosan (degree of deacetylation 95%) was dissolved in 100 mL of 1% acetic acid solution, 3 g of tea tree oil was added and emulsified at high speed, then 5 g of gelatin was added to adjust the pH to 4.0, and then 5 mL of 2% glutaraldehyde was added for cross-linking for 2 h. Finally, the microcapsules (particle size 10 - 15 μm) were collected by centrifugation; S6: Preparation of crop board: 80 parts of crop straw powder, 20 parts of polylactic acid (PLA), and 5 parts of microcapsules were mixed and then added to a twin-screw extruder for co-extrusion into sheets. The temperature of the twin-screw extruder was set at 170 - 190 °C, the screw speed was 180 rpm, and finally hot-pressed at 120 °C, with a pressure of 5 MPa and a time of 15 min; S7: Composite molding: The wood substrate treated in S4 and the sheet treated in S6 were coated with urea-formaldehyde resin to form a wood-based board and a sheet board, and then the blanks were formed by the form of single wood-based board or single sheet board or a mixture of wood-based board and sheet board stacked. The blanks were 3 - 5 layers and criss-crossed. Finally, the blanks were hot-pressed at 140 °C and 12 MPa for 40 min, and finally cut into board blanks; S8: Surface treatment: Coating treatment was carried out on the surface of the board blank.

[0008] Preferably, the crop straw includes rice husk, corn straw, wheat straw, and rice straw. The crop straw is composed of a single one of rice husk, corn straw, wheat straw, and rice straw, or a mixture of multiple ones.

[0009] Preferably, the surface treatment is spraying a composite solution of bamboo vinegar and chitosan. After natural drying for 24 h, a water-based nano-silver coating is roll-coated, and finally cured at 80 °C for 3 h.

[0010] Preferably, the chitosan composite solution is a mixture of 5% bamboo vinegar and 1.5% chitosan.

[0011] Preferably, the volume ratio of the ascorbic acid solution in S2 is 1:1.

[0012] Preferably, the solid content of the urea-formaldehyde resin in S7 is 65%, and the glue spreading amount is 180 g / m².

[0013] Preferably, the parameters of high-speed emulsification are 10000 rpm and a time of 5 min.

[0014] Preferably, the gelatin is a 5% aqueous solution.

[0015] Preferably, the particle size of the microcapsules is 10 - 15 μm.

[0016] Compared with the prior art, the present invention has the following beneficial effects: In the present invention, an antibacterial biomass composite floor uses renewable resources such as wood and crop straw as the core substrate. Through physical modification, chemical treatment, or composite processing, natural or synthetic antibacterial agents are evenly dispersed inside the substrate or fixed on the surface, thereby endowing the floor with efficient and lasting antibacterial performance. Its advantages lie in combining the renewability and low-carbon environmental protection characteristics of biomass materials with the hygienic safety of antibacterial functions, and it is applicable to places with high environmental hygiene requirements such as hospitals, schools, kindergartens, and families. Specific embodiments

[0017] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention. Embodiment

[0018] An antibacterial biomass composite floor combined with wood chip materials Substrate treatment: Wood chips pass through 100 meshes → treated with silane coupling agent KH570 (concentration 1%, soaked in ethanol solution for 2 h) → dried at 100 °C for 2 h to obtain wood powder; Preparation of photocatalytic layer: 5 g of nano-TiO₂ (nitrogen-doped, particle size 40 nm) is dispersed in 50 g of acrylate emulsion → add 0.5 g of dispersant (sodium hexametaphosphate) → ultrasonic dispersion for 30 min → obtain photocatalytic coating; Loading of antibacterial agent: Prepare 0.08 mol / L AgNO₃ solution, add wood powder and ultrasonic disperse for 40 min, then dropwise add 1 mol / L ascorbic acid solution for reduction reaction at room temperature for 1.5 h, and finally wash with water 3 times. The primary processed wood powder and crop straw powder are dried at 105 °C and then ground to obtain the primary processed wood powder for standby; Co-blending and extrusion: 60 parts of primary processed wood powder + 35 parts of high-density polyethylene (HDPE) + 5 parts of compatibilizer (PE-g-MAH) → premix → twin-screw extruder (temperature 180 - 200 °C, screw speed 200 rpm) → extruded into a wood substrate; Composite molding: Coat the wood substrate with urea-formaldehyde resin (solid content 65%, glue application amount 180 g / m²) → form a billet (3 layers arranged vertically and horizontally) → hot press at 140 °C and 12 MPa for 40 min → cut into a slab with dimensions of 1200 × 150 × 12 mm; Surface treatment: Spray bamboo vinegar and chitosan composite liquid, and after natural drying for 24 hours, roll-coat water-based nano-silver coating, and finally cure at 80℃ for 3 hours. Example

[0019] Antibacterial biomass composite flooring combined with crop straw materials, Straw treatment: rice husk, corn stalk, wheat straw, rice straw are crushed to 80 mesh → soaked in 1.5% NaOH solution for 24 hours → rinsed with water until neutral to obtain crop straw shreds; Antimicrobial agent loading: prepare 0.08mol / L AgNO3 solution, add crop straw shreds and ultrasonically disperse for 40min → add 1mol / L ascorbic acid solution (volume ratio 1:1) → reduce at room temperature for 1.5h → wash with water 3 times → dry at 105℃ → grind to obtain crop straw powder (water content ≤10%); Preparation of microcapsules: 5 g of chitosan (95% deacetylation) was dissolved in 100 mL of 1% acetic acid solution → 3 g of tea tree oil was added → high-speed emulsification (10,000 rpm, 5 min) → 5 g of gelatin (5% aqueous solution) was added → pH was adjusted to 4.0 → 5 mL of 2% glutaraldehyde was added for cross-linking for 2 h → microcapsules were collected by centrifugation (particle size 10-15 μm); Sheet preparation: 80 parts of crop straw powder + 20 parts of polylactic acid (PLA) + 5 parts of microcapsules → twin-screw extruder blending (temperature 170-190°C, screw speed 180rpm) → sheet extrusion → hot pressing at 120°C (pressure 5MPa, time 15min); Composite molding: Sheet coated with urea-formaldehyde resin (solid content 65%, glue coating amount 180g / m²) → assembly (5 layers crisscrossed) → hot pressing at 140℃, 12MPa for 40min → cutting into 1200×150×12mm slabs; Surface treatment: Spray bamboo vinegar and chitosan composite liquid, and after natural drying for 24 hours, roll-coat water-based nano-silver coating, and finally cure at 80℃ for 3 hours. Example

[0020] The wood base material processed from sawdust materials and the sheet material processed from crop straw are mixed and used, and the wood base material and the sheet material are mixed and assembled in the composite molding assembly process, and finally the assembly is hot pressed at 140°C and 12MPa for 40 minutes, and finally cut into slabs.

[0021] Quality testing of an antibacterial biomass floor combined with natural biomass materials according to the present invention

[0022] Quantitative test: Using ISO22196 standard, inoculate Escherichia coli (ATCC8739) and Staphylococcus aureus (ATCC6538) liquid (concentration 10 5CFU / mL), the viable count was measured after 24 h of culture, and the antibacterial rate was calculated (required to be ≥99%) Durability test: The sample was placed in an artificial accelerated aging chamber (ultraviolet irradiation for 8 h / d, humidity 70%, temperature 50 °C), and the antibacterial performance was tested every 30 days. The antibacterial rate was required to be ≥90% after 6 months; Test results: Antibacterial test: ISO22196, 24-h antibacterial rate ≥99.9%

[0023] Modulus of rupture: GB / T17657-2022, span 150 mm, loading speed 10 mm / min, required to be ≥30 MPa; Surface abrasion resistance: EN13329, using a Taber abrasion tester (CS-10 wheel, load 1000 g), mass loss ≤0.08 g after 1000 revolutions of abrasion; Test results: Modulus of rupture ≥25 MPa, water absorption ≤8% For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present invention.

Claims

1. A preparation method of an antibacterial biomass composite floor, characterized in that: It includes the following steps: S1: Pretreatment of raw materials: Pass the wood chips through a 100-mesh sieve, add silane coupling agent KH570 for treatment with a coupling agent concentration of 1%, then soak in an ethanol solution for 2 h, and finally dry at 100 °C for 2 h to obtain wood powder. Crush the crop straw through an 80-mesh sieve, treat it with a 1.5% NaOH solution for 24 h, and rinse with clear water until neutral to obtain the crushed crop straw for standby; S2: Loading of antibacterial agent: Prepare a 0.08 mol / L AgNO3 solution, add the wood powder or crushed crop straw and disperse ultrasonically for 40 min, then dropwise add a 1 mol / L ascorbic acid solution for a reduction reaction at room temperature for 1.5 h, and finally wash with clear water 3 times. After drying the initially processed wood powder and crop straw powder at 105 °C, grind them to obtain the initially processed wood powder and crop straw powder for standby; S3: Preparation of photocatalytic layer: Disperse 5 g of nano-TiO2 in 50 g of acrylate emulsion, and then add 0.5 g of dispersant and disperse ultrasonically for 30 min to obtain a photocatalytic coating; S4: Coextrusion of wood-based boards: Premix 60 parts of the initially processed wood powder, 35 parts of high-density polyethylene (HDPE), and 5 parts of compatibilizer (PE-g-MAH), and then extrude and form into a wood substrate through a twin-screw extruder. The temperature of the twin-screw extruder is set at 180 - 200 °C, and the screw speed is 200 rpm; S5: Preparation of microcapsules: Dissolve 5 g of chitosan (degree of deacetylation 95%) in 100 mL of 1% acetic acid solution, add 3 g of tea tree oil, emulsify at high speed, then add 5 g of gelatin to adjust the pH to 4.0, and then add 5 mL of 2% glutaraldehyde for crosslinking for 2 h. Finally, collect the microcapsules by centrifugation (particle size 10 - 15 μm); S6: Preparation of crop-based boards: Mix 80 parts of crop straw powder, 20 parts of polylactic acid PLA, and 5 parts of microcapsules, and then add them to a twin-screw extruder for coextrusion into sheets. The temperature of the twin-screw extruder is set at 170 - 190 °C, the screw speed is 180 rpm, and finally hot press at 120 °C, with a pressure of 5 MPa and a time of 15 min; S7: Composite forming: Coat the wood substrate treated in S4 and the sheet treated in S6 with urea-formaldehyde resin to form a wood-based board and a sheet board, and then form a billet in a form of a single wood-based board or a single sheet board or a mixture of wood-based boards and sheet boards stacked in a mixed manner. The billet is 3 - 5 layers and is staggered vertically and horizontally. Finally, hot press the billet at 140 °C and 12 MPa for 40 min, and finally cut it into a board blank; S8: Surface treatment: Perform a coating treatment on the surface of the board blank.

2. The preparation method of an antibacterial biomass composite floor according to claim 1, wherein: The crop straw includes rice husks, corn straw, wheat straw, and rice straw. The crop straw is composed of a single one of rice husks, corn straw, wheat straw, and rice straw, or a mixture of multiple ones.

3. The preparation method of an antibacterial biomass composite floor according to claim 1, characterized in that: The surface treatment is to spray a composite solution of bamboo vinegar and chitosan, dry naturally for 24 h, then roll-coat a water-based nano-silver coating, and finally cure at 80 °C for 3 h.

4. The preparation method of an antibacterial biomass composite floor according to claim 3, characterized in that: The chitosan composite solution is a mixture of 5% bamboo vinegar and 1.5% chitosan.

5. The preparation method of an antibacterial biomass composite floor according to claim 1, characterized in that: In S2, the volume ratio of the ascorbic acid solution is 1:

1.

6. The preparation method of an antibacterial biomass composite floor according to claim 1, characterized in that: In S7, the solid content of the urea-formaldehyde resin is 65%, and the amount of glue applied is 180 g / m².

7. The preparation method of an antibacterial biomass composite floor according to claim 1, characterized in that: The parameters of the high-speed emulsification are 10000 rpm and the time is 5 min.

8. The preparation method of an antibacterial biomass composite floor according to claim 1, wherein: The gelatin is a 5% aqueous solution.

9. The preparation method of an antibacterial biomass composite floor according to claim 1, wherein: The particle size of the microcapsules is 10 - 15 μm.