A high-calcium calcite-based non-antibacterial fresh-keeping composite substrate, a preparation method and application thereof

Abstract

The application discloses a high-calcium calcite-based non-sterilization fresh-keeping composite base material, which comprises the following components in a weight ratio: calcite powder 75-78%, polyolefin resin 16-20%, nano-silver-chitosan composite antibacterial agent 0.8-1.2%, montmorillonite-plant extract compound fresh-keeping additive 1.0-1.5%, compatibility agent 2.0-2.5%, processing additive 0.5-1.0% and anti-aging additive 0.3-0.5%. Compared with the prior art, the application has the advantages that a high-calcium calcite-based non-sterilization fresh-keeping composite base material with good scene adaptability and comprehensive functions, a preparation method and application thereof are provided.

Description

Technical Field

[0001] This invention relates to the field of polymer modified materials technology, specifically to a high-calcium calcite-based non-energy-killing and preservative composite substrate, its preparation method, and its application. Background Technology

[0002] With the rapid development of cold chain logistics, pharmaceuticals and healthcare, military equipment and other fields, the market has an urgent need for sterilization and preservation materials that are "energy-free, long-lasting and stable, safe and environmentally friendly, and cost-controllable". Related technologies focus on optimizing the mechanical properties of calcite-filled composite materials or realizing a single function.

[0003] Existing technologies mainly focus on optimizing the mechanical properties or achieving a single function of calcite-filled composite materials, which have the following significant drawbacks: Low calcium content and high cost: The calcium carbonate content of existing high-filled calcium carbonate polyethylene composite materials (such as CN108587027B) is usually only 40%-50%, resulting in high raw material costs and high consumption of petroleum-based resins, which makes it difficult to meet the needs of low-carbon production.

[0004] Poor functional synergy and reliance on energy consumption: Existing antibacterial materials (such as CN110156749B) mostly use single antibacterial agents such as nano zinc oxide, which can only achieve basic antibacterial effects, lack preservation function, have a short preservation period (generally ≤3 months), and some technologies require additional energy consumption (such as ultraviolet light, heating) to exert a bactericidal effect, thus limiting application scenarios.

[0005] Narrow scope of application: General-purpose products cannot meet the stringent requirements of GMP compliance (sterility, non-migration, low odor) in the pharmaceutical industry, nor can they meet the extreme environmental tolerance requirements of the military industry, such as resistance to radiation, salt spray, and extreme high and low temperature cycles.

[0006] Insufficient compatibility and performance balance: In high-calcium filler systems (>60%), inorganic powders are prone to agglomeration, leading to a significant decrease in the mechanical properties (tensile strength, toughness) of the substrate, and uneven distribution of functional additives. Existing technologies have failed to effectively solve the interfacial bonding and dispersion problems under high filler conditions.

[0007] Poor mass production compatibility: Some high-end functional materials require specialized production equipment, which involves large investment in modification, low mass production efficiency, and raw material utilization rate of less than 95%. There is a lack of optimized design for large-scale mass production.

[0008] Therefore, developing a high-performance composite substrate with high calcium content that can achieve synergistic sterilization and preservation without additional energy consumption and is adaptable to multiple scenarios, as well as its low-cost mass production process, has become a technical challenge that urgently needs to be solved in this field. Summary of the Invention

[0009] The technical problem to be solved by the present invention is to overcome the above-mentioned technical defects and provide a high-calcium calcite-based non-energy-killing and preservation composite substrate with good scene adaptability and comprehensive functions, as well as its preparation method and application.

[0010] To solve the above-mentioned technical problems, the technical solution provided by the present invention is as follows: a high-calcium calcite-based non-functional antibacterial and preservative composite substrate, comprising the following components in the indicated weight ratios: 75%–78% calcite powder, 16%–20% polyolefin resin, 0.8%–1.2% nano-silver-chitosan composite antibacterial agent, 1.0%–1.5% montmorillonite-plant extract compound preservative agent, 2.0%–2.5% compatibilizer, 0.5%–1.0% processing aid, and 0.3%–0.5% anti-aging aid.

[0011] Preferably, the calcite powder is surface modified with a silane coupling agent, and the compatibilizer is a Pg-MAH compatibilizer with a grafting rate of 2.0% to 2.5%.

[0012] Preferably, the calcite powder is 1250 mesh heavy calcium carbonate; The polyolefin resin is a blend of HDPE and LDPE; The silver content in the nano-silver-chitosan composite antibacterial agent is ≥3.0%; The plant extracts in the montmorillonite-plant extract compound preservative are selected from grapefruit extract, tea polyphenols, or rosemary extract. The processing aid is a compound of zinc stearate and EBS, with a total addition amount of 0.6%.

[0013] Another aspect of this invention discloses a method for preparing a high-calcium calcite-based non-functional antibacterial and preservative composite substrate, comprising the following steps: S1: The calcite powder is screened to remove impurities, and the resin raw materials and functional additives are dried and dehumidified. S2: Add the pretreated calcite powder, resin carrier, antibacterial agent, preservative, compatibilizer and processing aid into the mixing equipment in proportion, first perform low-speed premixing, and then heat up to perform high-speed hot mixing. S3: The uniformly mixed material is fed into the extruder unit for melting, plasticizing and shearing dispersion. The high-calcium filler system is homogenized through multi-stage temperature control and screw shearing action, and granules are obtained by underwater pelletizing. S4: The obtained granules are dried to remove surface moisture, and then injection molded, blow molded or extruded foamed according to the application requirements. After cooling, shaping, trimming and performance testing, the finished product is obtained.

[0014] Preferably, the calcite powder in S1 is filtered through a 200m sieve to remove impurities; The functional additives are dried at 65℃-75℃ for 2-3 hours to make masterbatch, and the resin raw materials are dried at 75℃-85℃ for 2.5-3.5 hours.

[0015] Preferably, the multi-stage temperature control in S3 includes a feeding stage of 130°C, a compression stage of 165°C, a melting stage of 175°C, and a die head stage of 170°C, wherein the screw speed is 320 r / min; The particle size of the pellets obtained by underwater pelletizing is 2.0mm-3.0mm.

[0016] Preferably, the rotational speed of the low-speed premixing in S2 is 150 r / min-250 r / min, and the time is 3 min-8 min; The high-speed hot mixing temperature is 80℃-95℃, the rotation speed is 800r / min-1000r / min, and the time is 15min-25min.

[0017] Another aspect of the present invention discloses the application of a high-calcium calcite-based non-functional antibacterial and preservative composite substrate in the preparation of packaging containers or films with antibacterial and preservative functions.

[0018] Preferably, the packaging container or film includes a cold chain logistics fresh food turnover box, a sterile food preservation film, a medical device storage box, or a military field material protective cover.

[0019] The advantages of this invention compared with the prior art are as follows: the material provided by this invention has significant synergistic functions and economic benefits. Through the non-energetic combination of nano-silver-chitosan and plant extracts, it achieves broad-spectrum sterilization and long-lasting preservation. The material provided by this invention has stable and reliable performance in different scenarios. The innovative high-calcium filling system effectively solves the problem of agglomeration while significantly reducing raw material costs and maintaining excellent mechanical properties. The material of this invention has strong thermal stability and a wide range of applications, and can seamlessly meet the standards for food contact, pharmaceutical GMP aseptic and military extreme environments without the need for separate research and development. The process is compatible with existing production lines, allows for rapid modification, has high capacity, and a raw material utilization rate of ≥99.5%. Furthermore, all components are non-toxic, environmentally friendly, and recyclable, perfectly aligning with low-carbon policies and possessing extremely high value for large-scale promotion. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the composite substrate preparation process.

[0021] Figure 2 This is a schematic diagram of the composite substrate preparation process. Figure 2 .

[0022] Figure 3 It is a bar chart comparing the formula ratios for different scenarios.

[0023] Figure 4 This is a line graph comparing the long-lasting antibacterial properties.

[0024] Figure 5 This is a comparison diagram of the microstructure of the high-calcium filling system.

[0025] Figure 6 This is a comparison chart of thermal performance in different scenarios.

[0026] Figure 7 It is a cost comparison bar chart.

[0027] As shown in the figure: Figure 1 The exhibition showcases 12 core processes, including raw material selection, pretreatment, precise batching, high-speed mixing, melt extrusion, underwater pelletizing, drying, screening and grading, molding and processing, post-processing, finished product testing, and packaging and warehousing. It also highlights key equipment (such as twin-screw extruders and high-speed mixers) and process parameters (temperature, speed, and time) for each process, and emphasizes specific steps for pharmaceutical and military applications (aseptic processing, secondary extrusion, and gradient cooling).

[0028] Figure 3 The horizontal axis represents general / pharmaceutical / military applications, and the vertical axis represents the raw material mass fraction (%). The column items include calcite powder, HDPE / LDPE blended resin, antibacterial agent, preservative, compatibilizer, processing aid, modifying aid, and anti-aging aid, distinguished by different colors and textures, and labeled with specific values.

[0029] Figure 4 The horizontal axis represents the usage time (0-18 months), and the vertical axis represents the antibacterial rate (%). The line graph includes the antibacterial rates of Escherichia coli in general scenarios, Staphylococcus aureus in general scenarios, Pseudomonas aeruginosa in pharmaceutical scenarios, and Escherichia coli in extreme environments in military scenarios. Key data for 6 / 12 / 18 months are marked.

[0030] Figure 5 The left side shows the unmodified calcite and resin mixture structure (10μm scale), labeled "calcite agglomeration", "obvious interfacial gaps", and "poor mechanical properties"; the right side shows the structure after modification with silane coupling agent (same scale), labeled "uniformly dispersed calcite", "tight interfacial bonding", and "excellent mechanical properties".

[0031] Figure 6 The thermogravimetric analysis curves are shown, with the horizontal axis representing temperature (0-300℃) and the vertical axis representing mass retention rate (%). The curve terms represent substrates for general / pharmaceutical / military applications, and the mass retention rates at key temperature points of 200℃ / 220℃ / 250℃ are marked.

[0032] Figure 7The horizontal axis represents the same type of ordinary products, the same type of high-end products, and the general / pharmaceutical / military application products of this invention. The vertical axis represents the cost per ton (yuan), with specific values ​​and cost reductions indicated. Detailed Implementation

[0033] The present invention will now be described in further detail with reference to the accompanying drawings.

[0034] This invention is based on the core concept of "high calcium filling + functional synergy + multi-scenario adaptation + mass production compatibility", and achieves technological breakthroughs through optimized formulation system and continuous process design: 1. Formulation Design: Calcite powder (≥75%) is used as the main raw material, combined with HDPE / LDPE blended resin. Using it as a carrier, a compound antibacterial agent of nano-silver-chitosan and a preservative agent of montmorillonite-plant extract are combined, along with compatibilizers and modifiers. Through the selection and proportion control of raw materials, the high calcium filling and sterilization and preservation functions are synergistically achieved.

[0035] 2. Modification technology: Silane coupling agent is used to modify the surface of calcite powder, combined with PP-g-MAH compatibilizer (grafting rate 2.0%-2.5%) to solve the agglomeration and compatibility problems of high calcium system.

[0036] 3. Scenario-based adjustments: For general, pharmaceutical, and military scenarios, raw material specifications, formula ratios, and process parameters are optimized to adapt to the specific requirements of different scenarios.

[0037] 4. Mass production process: Design a continuous process of "raw material screening - pretreatment - precise batching - high-speed mixing - melt extrusion - underwater pelletizing - drying - molding and processing - post-processing - inspection and warehousing", which is compatible with existing production lines and ensures large-scale mass production.

[0038] Example 1: General-purpose substrate (suitable for cold chain logistics packaging) 1. Formulation composition (mass fraction): 76% calcite powder, HDPE / LDPE blend resin (HDPE:LDPE=7:3) 17%, Nano silver-chitosan composite antibacterial agent 1.0%, Montmorillonite-grapefruit extract compound preservative agent 1.2%, PP-g-MAH compatibilizer (grafting rate 1.5%) 2.2%, Zinc stearate + EBS (1:1) 0.6%, Anti-aging agent (1010:UV-531=1:1) 0.4%.

[0039] 2. Raw material specifications: Calcite powder, calcium carbonate content 98.5%, particle size 1500 mesh, surface pretreated with silane coupling agent; HDPE melt flow rate 3g / 10min, LDPE melt flow rate 4g / 10min; nano- The silver particles are 30 nm in diameter, and the chitosan has a molecular weight of 80,000.

[0040] 3. Work process: (1) Raw material screening: Raw materials are screened using a 100-mesh vibrating screen, and calcite powder is additionally screened through a 200-mesh screen to remove large particles; (2) Pretreatment: The functional additives are dried at 70℃ for 2.5h to prepare masterbatch, and the resin is dried at 80℃ for 3h until the moisture content is ≤0.08%; (3) Ingredient mixing: The fully automatic batching system batches the ingredients according to the ratio, stirs at 200 r / min for 5 min, and then mixes at 85℃ and 900 r / min for 18 min at high speed; (4) Melt extrusion: Feed section 130℃, compression section 165℃, melting section 175℃, die head section 170℃, screw speed 320r / min; (5) Post-treatment: underwater pelleting (particle size 2.5mm), drying at 70℃ Injection molding for 35 minutes (temperature 165℃, pressure 20MPa), followed by natural cooling, trimming, and inspection.

[0041] (5) Performance results: Calcium carbonate content 76.3%, Escherichia coli antibacterial rate 99.92%, oxygen permeability 48cm³ / (m²·24h·atm), tensile strength 15.8MPa, cost per ton 2980 yuan, 22% lower than similar products.

[0042] Example 2: Substrate for pharmaceutical applications (suitable for aseptic pharmaceutical packaging) 1. Formulation composition (mass fraction): 75.5% calcite powder, pharmaceutical grade HDPE / LDPE blend resin 17.5%, pharmaceutical-grade nano-silver-chitosan antibacterial agent 1.5%, pharmaceutical-grade montmorillonite-tea polyphenol compound preservative 1.8%, high-grafting-rate PP-g-MAH compatibilizer 2.8%, pharmaceutical-grade zinc stearate + EBS 0.8%, medical Pharmaceutical grade silane coupling agent 0.5%, low migration anti-aging additive 0.7%.

[0043] 2. Core adjustments: All raw materials are pharmaceutical grade (calcite powder has no heavy metal residue, and the resin meets USP Class VI standards), the batching environment is Class 100 cleanroom, the melt extrusion temperature is reduced by 8℃, the cooling water is sterile, and after molding, it is cured at 45℃ in a Class 100 cleanroom environment for 30 hours.

[0044] 3. Performance results: Antibacterial rate ≥99.99%, oxygen permeability 28cm³ / (m²·24h·atm), sterility test meets the standard, complies with GMP standards, and the cost per ton is 3950 yuan, a reduction of 18%.

[0045] Example 3: Military-grade substrate (suitable for field storage materials) 1. Formulation composition (mass fraction): 75% calcite powder, blended resin containing 30% ultra-high molecular weight PE 16.5%, nano silver-chitosan-titanium dioxide composite antibacterial agent 1.5%, organic modified montmorillonite preservative 2.0%, PP-g-MAH compatibilizer 3.0%, processing aid containing 15% polytetrafluoroethylene micro powder 0.9%, high-purity silane coupling agent 0.6%, and anti-aging aid containing 25% carbon black micro powder 0.5%.

[0046] 2. Core adjustments: After modification, calcite powder is aged at -20℃ for 2 hours. A secondary extrusion unit is added to the melt extrusion process. Gradient cooling (25℃→0℃→25℃) is adopted in the post-processing. Particle strength testing is added after screening.

[0047] 3. Performance results: Radiation resistance 1.2 × 10⁻⁶ 5 Gy, resistant to salt spray for 1000 hours without corrosion, tensile strength 20.5MPa, meets low-temperature impact resistance at -40℃, and conforms to GJB 9001C standard.

[0048] The contents not described in detail in this specification are existing technologies known to those skilled in the art.

[0049] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0050] The present invention and its embodiments have been described above. This description is not restrictive, and the accompanying drawings are only one embodiment of the present invention; the actual structure is not limited thereto. In conclusion, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the spirit of the invention, such designs should fall within the protection scope of the present invention.

Claims

1. A high-calcium calcite-based non-functional antibacterial and preservative composite substrate, characterized in that: It includes the following components in the following weight ratios: calcite powder 75%–78%, polyolefin resin 16%–20%, nano-silver-chitosan composite antibacterial agent 0.8%–1.2%, montmorillonite-plant extract compound preservative agent 1.0%–1.5%, compatibilizer 2.0%–2.5%, processing aid 0.5%–1.0%, and anti-aging aid 0.3%–0.5%.

2. The high-calcium calcite-based non-functional antibacterial and preservative composite substrate according to claim 1, characterized in that: The calcite powder is surface modified with a silane coupling agent, and the compatibilizer is a Pg-MAH compatibilizer with a grafting rate of 2.0% to 2.5%.

3. The high-calcium calcite-based non-functional antibacterial and preservative composite substrate according to claim 1, characterized in that: The calcite powder is 1250 mesh heavy calcium carbonate; The polyolefin resin is a blend of HDPE and LDPE; The silver content in the nano-silver-chitosan composite antibacterial agent is ≥3.0%; The plant extracts in the montmorillonite-plant extract compound preservative are selected from grapefruit extract, tea polyphenols, or rosemary extract. The processing aid is a compound of zinc stearate and EBS, with a total addition amount of 0.6%.

4. A method for preparing a high-calcium calcite-based non-functional antibacterial and preservative composite substrate according to any one of claims 1-3, characterized in that: Includes the following steps: S1: The calcite powder is screened to remove impurities, and the resin raw materials and functional additives are dried and dehumidified. S2: Add the pretreated calcite powder, resin carrier, antibacterial agent, preservative, compatibilizer and processing aid into the mixing equipment in proportion, first perform low-speed premixing, and then heat up to perform high-speed hot mixing. S3: The uniformly mixed material is fed into the extruder unit for melting, plasticizing and shearing dispersion. The high-calcium filler system is homogenized through multi-stage temperature control and screw shearing action, and granules are obtained by underwater pelletizing. S4: The obtained granules are dried to remove surface moisture, and then injection molded, blow molded or extruded foamed according to the application requirements. After cooling, shaping, trimming and performance testing, the finished product is obtained.

5. The preparation method according to claim 4, characterized in that: The S1 calcite powder is purified by a 200m sieve. The functional additives are dried at 65℃-75℃ for 2-3 hours to make masterbatch, and the resin raw materials are dried at 75℃-85℃ for 2.5-3.5 hours.

6. The preparation method according to claim 4, characterized in that: The multi-stage temperature control in S3 includes a feeding section of 130°C, a compression section of 165°C, a melting section of 175°C, and a die head section of 170°C, wherein the screw speed is 320 r / min; The particle size of the pellets obtained by underwater pelletizing is 2.0mm-3.0mm.

7. The preparation method according to claim 4, characterized in that: The low-speed premixing speed in S2 is 150 r / min-250 r / min, and the time is 3 min-8 min; The high-speed hot mixing temperature is 80℃-95℃, the rotation speed is 800r / min-1000r / min, and the time is 15min-25min.

8. The application of a high-calcium calcite-based non-functional antibacterial and preservative composite substrate as described in any one of claims 1-3 in the preparation of packaging containers or films with antibacterial and preservative functions.

9. The application according to claim 8 in the preparation of packaging containers or films with antibacterial and preservative functions, characterized in that: The packaging containers or films include cold chain logistics fresh food turnover boxes, aseptic food preservation films, medical-grade medical device storage boxes, or military field material protective covers.

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