Plant fragrance type acetic acid plate and preparation method thereof

Abstract

The invention belongs to the technical field of acetic acid boards, and provides a plant aroma type acetic acid board and a preparation method thereof. 10 to 20 weight percent of plasticizer; 5-15 wt% of a solvent; the microcapsule-coated plant essence is 1-5wt%, the particle size of the microcapsule is less than or equal to 50 microns, and a coating layer is polyvinyl alcohol; 0.2-1 wt% of an ultraviolet light absorber; 0.1 to 0.5 wt% of an antioxidant; double-layer microcapsule wrapping is adopted, a dynamic pressurization process is combined, direct contact between essence and a base material is effectively isolated through a microcapsule barrier, surface oil stain precipitation is remarkably reduced, and smoothness is improved; the dispersion process is optimized to enhance the structural uniformity of the base material and obviously improve the mechanical property of the plate; long-acting slow release of the essence is realized, the material is endowed with a composite function, and the application scene of the acetic acid plate is expanded.

Description

Technical Field

[0001] The invention belongs to the technical field of acetate sheets, in particular to a plant-scented acetate sheet and a preparation method thereof. Background Art

[0002] Traditional acetate sheeting uses cellulose acetate as its primary raw material, manufactured through processes such as kneading, calendering, and drying. Its advantages lie in its high plasticity, environmental friendliness, non-toxicity, and ease of processing into products such as eyeglass frames and decorative materials. The acetate sheeting process involves cellulose preparation, cellulose dissolution, cellulose regeneration, cellulose fiberization, and fiberboard forming. Finally, in the fiberboard forming process, the fiberized cellulose is molded through a molding machine to produce acetate sheeting of varying specifications and sizes.

[0003] Traditional acetate sheets only focus on basic physical properties, such as strength and toughness, and do not involve sensory experience or additional functions. Directly adding flavors can easily lead to oil stains on the surface of the sheet, and the flavors have poor compatibility with cellulose acetate, affecting the mechanical properties of the sheet.

[0004] Therefore, those skilled in the art have proposed a plant-flavored acetic acid plate and a preparation method thereof to solve the problems raised in the background art. Summary of the Invention

[0005] In order to solve the above technical problems, the present invention provides a plant-flavored acetate sheet and a preparation method thereof, so as to solve the problems in the prior art that directly adding flavors to acetate sheets easily leads to oily precipitation on the surface of the sheets, and the flavors have poor compatibility with cellulose acetate, which affects the mechanical properties of the sheets.

[0006] A plant-scented acetate sheet comprises the following components: 60-80 wt% of cellulose acetate; 10-20 wt% of a plasticizer; 5-15 wt% of a solvent; 1-5 wt% of a plant essence encapsulated in microcapsules, wherein the particle size of the microcapsules is ≤50 μm and the coating layer is polyvinyl alcohol; 0.2-1 wt% of an ultraviolet absorber; and 0.1-0.5 wt% of an antioxidant.

[0007] Preferably, the plant fragrance is selected from at least one of lavender, rose, and jasmine, and the inner layer of the fragrance microcapsule is a porous starch carrier, and the outer layer is a polyvinyl alcohol cross-linked film.

[0008] Preferably, the invention further comprises 0.5-2 wt% of an antibacterial agent, wherein the antibacterial agent is tea tree essential oil microcapsules.

[0009] A method for preparing a plant-flavored acetic acid plate comprises the following steps:

[0010] S1. Kneading: Mix cellulose acetate, plasticizer, solvent, microcapsule essence and additives, and stir at 40-60°C for 30-60 minutes;

[0011] S2, filtration: filter out impurities through a 50-70℃ jacketed extruder;

[0012] S3. Calendering and plasticizing: Plasticizing in a double-roll calender at 80-100℃ to make the solvent volatilization rate ≥90%;

[0013] S4, briquetting: pressurize the colloid in sections to 0-10 MPa and maintain the pressure for 10-20 minutes;

[0014] S5, flaking: cold flaking into sheets with a thickness of 0.5-3mm;

[0015] S6. Drying: Dry in a drying room at 40-50℃;

[0016] S7, Flattening packaging: Stainless steel plates are clamped and flattened, and the surface is covered with a protective film.

[0017] Preferably, the segmented pressurization in the briquetting process includes:

[0018] The first stage: 0-5MPa, hold pressure for 5 minutes;

[0019] The second stage: 5-10MPa, maintain pressure for 10 minutes.

[0020] Preferably, the linear speed of the calendering and plasticizing process is 5-10 m / min, and the roller temperature deviation is ≤±2°C.

[0021] Preferably, the humidity in the drying process is controlled to be ≤30%, and the residual solvent content is ≤0.1%.

[0022] Preferably, the surface roughness of the sheet in the flaking process is Ra≤1.6 μm.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] This acetate sheet is wrapped with double-layer microcapsules and combined with a dynamic pressurization process. The microcapsule barrier effectively isolates the direct contact between the essence and the substrate, significantly reducing the precipitation of surface oil stains and improving the smoothness. The optimized dispersion process enhances the uniformity of the substrate structure and significantly improves the mechanical properties of the sheet. It achieves long-term sustained release of the essence and gives the material composite functions, expanding the application scenarios of acetate sheets and solving the problems of poor compatibility, performance degradation and single function in traditional processes. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the overall structure of the present invention; DETAILED DESCRIPTION

[0026] The following embodiments of the present invention are described in further detail with reference to the accompanying drawings and examples. The following examples are used to illustrate the present invention but are not intended to limit the scope of the present invention.

[0027] As attached Figure 1 As shown: The present invention provides a plant-scented acetate sheet, comprising the following components: 60-80wt% of cellulose acetate; 10-20wt% of plasticizer; 5-15wt% of solvent; 1-5wt% of plant essence encapsulated in microcapsules, the microcapsule particle size is ≤50μm, and the coating layer is polyvinyl alcohol; 0.2-1wt% of ultraviolet absorber; and 0.1-0.5wt% of antioxidant.

[0028] The plant fragrance is selected from at least one of lavender, rose, and jasmine, and the inner layer of the fragrance microcapsule is a porous starch carrier and the outer layer is a polyvinyl alcohol cross-linked film; the fragrance microcapsule also contains 0.5-2wt% of an antibacterial agent, which is tea tree essential oil microcapsules;

[0029] The flavor microcapsules adopt a double-layer coating structure, which solves the problem of flavor volatilization during high-temperature processing (volatility rate ≤5%, traditional process ≥30%); achieves sustained release of flavor, with a release period ≥36 months; ultraviolet absorbers (benzotriazoles) are embedded in the microcapsule coating layer to form a chemically bonded composite film; the UV-A blocking rate is increased from 90% to 98%, and the flavor release rate is reduced by 20%; the amount of ultraviolet absorber used is reduced (from 1wt% to 0.5wt%), thereby reducing costs.

[0030] The preparation steps include:

[0031] S1. Kneading: Add cellulose acetate, plasticizer, solvent, microcapsule essence and other additives into a kneader in proportion and stir at 40-60°C for 30-60 minutes; at a temperature of 40-60°C, a stirring speed of 20-40 rpm, and a time of 30-60 minutes to ensure uniform dispersion and no breakage of the microcapsules;

[0032] S2. Filtration: Filter the colloid through a 50-70℃ jacketed extruder to remove undispersed particulate impurities; filter the impurities with a 200-300 mesh filter to ensure the purity of the colloid;

[0033] S3. Calendering and plasticizing: Plasticizing in a double-roll calender at 80-100℃, making the solvent volatilization rate ≥90%, the linear speed of the calendering and plasticizing process is 5-10m / min, and the roller temperature deviation is ≤±2℃;

[0034] S4, briquetting: pressurize the colloid in stages to 0-10 MPa and maintain the pressure for 10-20 minutes; the stage 1 pressurization in the briquetting process includes: the first stage: 0-5 MPa, maintaining the pressure for 5 minutes; the second stage: 5-10 MPa, maintaining the pressure for 10 minutes;

[0035] S5. Flaking: Use a flaker to cold-plan the block, the temperature is ≤25℃, the sheet thickness is 0.5-3mm, and the surface roughness Ra is ≤1.6μm;

[0036] S6. Drying: Dry in a drying room at 40-50℃ for 12-24 hours. The specific time depends on the size. During the drying process, the humidity should be controlled at ≤30% and the residual solvent content should be ≤0.1%.

[0037] S7. Flattening and packaging: clamp the dried sheet between stainless steel plates, flatten it at room temperature with a pressure of 0.5-1MPa, and cover the surface with PET protective film to prevent the volatilization of the flavor and scratches.

[0038] Example 1: Preparation of lavender-scented acetic acid sheet:

[0039] Formula: Cellulose acetate: 72%;

[0040] Dioctyl phthalate (plasticizer): 15%;

[0041] Acetone (solvent): 10%;

[0042] Lavender essence microcapsules (particle size 30 μm): 2.5%;

[0043] Benzotriazole UV absorber: 0.3%;

[0044] Antioxidant 1010: 0.2%.

[0045] Process parameters:

[0046] Kneading: temperature 50°C, rotation speed 30 rpm, time 40 minutes.

[0047] Calendering plasticization: roller temperature 90℃, line speed 8m / min.

[0048] Briquetting: Pressurize to 8MPa in stages, with a total holding time of 15 minutes.

[0049] Drying: 45°C, 25% humidity, 18 hours.

[0050] Performance testing:

[0051] Fragrance release (28 days): 0.12mg / m 3 .

[0052] UV-A blocking rate: 92%.

[0053] Tensile strength: 26.5MPa.

[0054] The briquetting process uses an intelligent segmented pressurization system (0→5→10MPa), combined with sensors to monitor the distribution density of microcapsules in real time. The pressure is dynamically adjusted to avoid local excessive pressure that may cause microcapsule rupture (rupture rate ≤1%, traditional briquetting process ≥5%). The uniformity of the board density is improved (deviation ≤2%), and the tensile strength is increased to 28.8MPa (traditional process ≤25MPa). The essence is tightly bonded to the base material, and there is no oil precipitation on the surface (passed the GB / T 1731 adhesion test).

[0055] This board and preparation method integrates fragrance sustained release, UV protection, and antibacterial functions into a single board for the first time, achieving functional synergy through microcapsule structure design, composite membrane layer bonding, and intelligent pressurization technology.

[0056] Example 2: Making Rose / Jasmine Composite Fragrance Plates:

[0057] formula:

[0058] Cellulose acetate: 68%;

[0059] Triethyl citrate (plasticizer): 18%;

[0060] Ethyl acetate (solvent): 10%;

[0061] Rose essence microcapsule: 2%;

[0062] Jasmine essence microcapsule: 1%;

[0063] Benzophenone UV absorber: 0.5%;

[0064] Tea tree essential oil microcapsules (antibacterial agent): 0.5%.

[0065] Process optimization:

[0066] 0.1% zinc stearate was added during the kneading stage to improve demoulding properties.

[0067] The briquetting pressure is divided into three sections: 0 → 3 MPa (5 minutes) → 6 MPa (5 minutes) → 10 MPa (5 minutes).

[0068] Performance testing:

[0069] Inhibition zone diameter (Staphylococcus aureus): 9.2 mm.

[0070] Fragrance release period: 30 months (accelerated aging prediction).

[0071] Example 3: Lavender-Rose Composite Fragrance Acetate Sheet

[0072] Formula: Cellulose acetate (70wt%), cellulose diacetate (DS=2.4) with a degree of polymerization of 300-400 is selected. Its strong hydrogen bonding between molecular chains gives the board excellent mechanical properties and thermal stability; by adjusting the molecular weight distribution (Mw / Mn≤2.5), the melt fluidity is optimized to avoid the appearance of orange peel texture during the calendering process.

[0073] Dioctyl phthalate (15wt%) is selected. Dioctyl phthalate (DOP) has a high boiling point (386°C) and low volatility, and its compatibility with cellulose acetate is over 89%. It can lower the glass transition temperature (Tg) to 120°C and improve processability. The plasticizer ratio is verified by DSC testing to ensure the formation of a stable amorphous structure during the calendering and plasticization stage.

[0074] Acetone (10 wt%), using industrial grade acetone (purity ≥ 99.5%), its solubility parameter (δ = 9.8 (cal / cm 3 )^0.5) matches cellulose acetate (δ=10.3) to form a homogeneous solution; the solvent evaporation gradient is determined by rheological testing to avoid internal stress during the drying process.

[0075] Fragrance microcapsules, lavender 2% + rose 2%:

[0076] Lavender essence microcapsules: The inner layer is porous starch (particle size 30μm, specific surface area 120m 2 / g), the outer layer is a cross-linked polyvinyl alcohol film (thickness 200nm), and the embedding rate reaches 85%.

[0077] Rose essence microcapsules: Pre-treated with β-cyclodextrin (inclusion rate 72%) to reduce the polarity difference between the aroma molecules and cellulose acetate and improve compatibility; the composite fragrance ratio is analyzed by gas chromatography-mass spectrometry (GC-MS) to ensure the synergistic effect of the aromas of lavender (linalool accounts for 45%) and rose (geraniol accounts for 38%).

[0078] Benzotriazole UV absorber 0.3%: Select UV-327, which has a maximum absorption wavelength of 345nm and can effectively block more than 90% of UV-A (320-400nm).

[0079] Antioxidant 1010: 0.2%, verified by thermogravimetric analysis (TGA), after addition, the initial decomposition temperature of the board increased from 270°C to 295°C.

[0080] Antibacterial agent (tea tree essential oil microcapsules, 0.5%): The microcapsule particle size is 15μm, the core material is 1,8-cineole (accounting for 60%), the outer layer is a chitosan-sodium alginate composite film, and the sustained-release period is up to 6 months.

[0081] Process parameters:

[0082] Kneading: A twin-screw kneader (L / D = 40) was used with a temperature gradient (40°C → 50°C → 60°C) to ensure that the plasticizer gradually penetrated the cellulose molecular chains. At a rotation speed of 30 rpm, the material fluidity was monitored using a torque sensor. Kneading was terminated when the torque value stabilized at 80 ± 5 N·m to prevent microcapsule rupture.

[0083] Filtration and plasticization: A 300-mesh stainless steel filter is used in conjunction with ultrasonic vibration (frequency 20kHz) to remove undispersed cellulose particles (particle size > 50μm). During the calendering and plasticization stage, an infrared thermal imager is used to monitor the uniformity of the roller surface temperature (deviation ≤±1°C) to ensure that the solvent volatilization rate reaches 92%.

[0084] Briquetting and flaking: The segmented pressurization process (0→5MPa→10MPa) has been verified by finite element simulation to reduce the internal porosity to below 0.3%. The cold planing temperature is controlled at 20°C, and PCD tools (edge radius 5μm) are used. The surface roughness Ra=1.2μm meets the requirements of optical-grade sheet materials.

[0085] Drying and packaging: The drying process uses a dehumidifier + circulating air system, and the humidity gradient is controlled (30% → 20% → 15%) to avoid warping caused by solvent residue; the flattening process uses a servo hydraulic press (accuracy ± 0.01MPa), the surface PET film thickness is 50μm, and the oxygen permeability is <0.5cm 3 / (m 2 ·day), effectively blocking the volatilization of fragrance.

[0086] Performance testing:

[0087] The dynamic headspace-GC-MS coupling technology (ASTME1759) was used to monitor the sustained release curve of the microcapsules at 25°C / 50% RH for 28 days. It was found that the release peak of the lavender and rose compound fragrance was reached on the 7th day (0.008 mg / m 3 ), and still maintained at 0.001 mg / m after 28 days 3 Stable release;

[0088] Optical properties: UV-A blocking rate (91%) and light transmittance (82%) were tested using a UV-visible spectrophotometer (λ = 200-800nm). Combined with a yellowing index of ΔE = 2.3 (≤3 is excellent) after xenon lamp aging (1000h), the synergistic protective effect of the UV absorber and antioxidant was verified.

[0089] Mechanical properties: According to GB / T1040-2006 standard, the tensile strength (27.2MPa), elongation at break (18%) and impact strength (6.5kJ / m 2), the results are better than those of traditional acetate sheets (tensile strength 22-25MPa), which is attributed to the reduction of internal defects by the segmented pressing process;

[0090] Antibacterial properties: The agar diffusion method (ASTM E2149-13) was used to test Escherichia coli (inhibition rate 99.6%) and Staphylococcus aureus (inhibition zone 9.2 mm), confirming the sustained-release antibacterial effect of tea tree essential oil microcapsules;

[0091] Environmental adaptability: After wet heat aging (85°C / 85% RH, 1000h), the mass loss is less than 0.1% and the solvent residue is ≤0.1%, verifying the process stability;

[0092] Sensory evaluation: A blind test was conducted by a panel of 10 people. 90% of the subjects believed that the compound fragrance was natural and soft, without chemical irritation, and met the ISO12243 sensory standard.

[0093] This board uses porous starch-polyvinyl alcohol composite microcapsules (particle size ≤ 50μm) to encapsulate plant essences. The inner porous structure absorbs aroma molecules, while the outer cross-linked membrane isolates them from direct contact with cellulose acetate, avoiding compatibility issues caused by polarity conflicts, fundamentally suppressing surface oil precipitation, and maintaining the board's smoothness. The microcapsule's sustained-release mechanism extends the aroma release cycle to over 30 months, significantly superior to traditional direct addition methods.

[0094] The internal porosity is reduced to below 0.3% through a staged pressurization process (0→5MPa→10MPa), and the internal stress is controlled by gradient drying, so that the tensile strength of the plate reaches 26.5-27.2MPa (traditional plate 22-25MPa), the elongation at break is 18%, and the impact strength is 6.5kJ / m 2 , comprehensive mechanical properties are improved;

[0095] Tea tree essential oil microcapsules (0.5% to 1.2%) achieve long-lasting antibacterial effects, with an inhibition rate of 99.6% against Staphylococcus aureus and an inhibition zone of 9.2-10.3 mm. Ultraviolet absorbers (UV-A blocking rate of 91% to 92%) are combined with antioxidants to ensure that the yellowing index ΔE of the board is ≤ 2.3 after wet heat aging (85°C / 85% RH, 1000h), significantly enhancing its weather resistance.

[0096] The twin-screw kneader's gradient temperature increase (40°C → 60°C) ensures uniform dispersion of the material, ultrasonic-assisted filtration (300-mesh filter) removes impurities, and the cold planing process (surface roughness Ra ≤ 1.6μm) improves molding accuracy. The residual solvent is ≤ 0.1%, meeting food contact safety standards, and energy consumption is reduced by more than 20%, making it environmentally friendly.

[0097] The embodiments of the present invention are provided for the purpose of illustration and description. Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations of the present invention. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A plant-flavored acetic acid sheet, characterized in that: The invention comprises the following components: 60-80 wt% of cellulose acetate; 10-20 wt% of plasticizer; 5-15 wt% of solvent; 1-5 wt% of plant essence wrapped in microcapsules, wherein the particle size of the microcapsules is ≤50 μm and the coating layer is polyvinyl alcohol; 0.2-1 wt% of ultraviolet absorber; and 0.1-0.5 wt% of antioxidant.

2. The plant-flavored acetic acid sheet according to claim 1, characterized in that: The plant fragrance is selected from at least one of lavender, rose and jasmine, and the inner layer of the fragrance microcapsule is a porous starch carrier, and the outer layer is a polyvinyl alcohol cross-linked film.

3. The plant-flavored acetic acid sheet according to claim 2, characterized in that: The invention also contains 0.5-2 wt% of an antibacterial agent, which is tea tree essential oil microcapsule.

4. A method for preparing a plant-flavored acetic acid sheet, used in conjunction with any one of the plant-flavored acetic acid sheets according to claims 1-3, characterized in that: The following steps are involved: S1. Kneading: Mix cellulose acetate, plasticizer, solvent, microcapsule essence and additives, and stir at 40-60°C for 30-60 minutes; S2, filtration: filter out impurities through a 50-70℃ jacketed extruder; S3, calendering and plasticizing: plasticizing in a double-roll calender at 80-100℃; S4, briquetting: pressurize the colloid in sections to 0-10 MPa and maintain the pressure for 10-20 minutes; S5, flaking: cold flaking into sheets with a thickness of 0.5-3mm; S6. Drying: Dry in a drying room at 40-50℃; S7, Flattening packaging: Stainless steel plates are clamped and flattened, and the surface is covered with a protective film.

5. The method for preparing a plant-flavored acetic acid sheet according to claim 4, wherein: The segmented pressurization in the briquetting process includes: The first stage: 0-5MPa, hold pressure for 5 minutes; The second stage: 5-10MPa, maintain pressure for 10 minutes.

6. The method for preparing a plant-flavored acetic acid sheet according to claim 4, wherein: The linear speed of the calendering and plasticizing process is 5-10 m / min, and the roller temperature deviation is ≤±2°C.

7. The method for preparing a plant-flavored acetic acid sheet according to claim 4, wherein: During the drying process, the humidity is controlled to be ≤30% and the residual solvent content is ≤0.1%.

8. The method for preparing a plant-flavored acetic acid sheet according to claim 4, wherein: The surface roughness of the sheet in the flaking process is Ra≤1.6 μm.

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