Antibacterial plastic bottle embryo for food and preparation method thereof

Abstract

The present invention belongs to the technical field of polymer materials, and provides an antibacterial plastic bottle embryo for food and a preparation method thereof. The plastic bottle embryo at least comprises the following components: polyethylene terephthalate (PET), chitosan-modified polypropylene fiber antibacterial masterbatch, dendritic quaternary ammonium salt polymer antibacterial agent, isooctyl thioglycolate, carbonate and other additive components; the chitosan-modified polypropylene fiber antibacterial masterbatch is added to the outer layer injection mold; the chitosan-modified polypropylene fiber antibacterial masterbatch is added to the inner layer injection mold in combination with the dendritic quaternary ammonium salt polymer antibacterial agent. The bottle embryo prepared according to the present application has the characteristics of both low cost and high antibacterial efficiency, and the outer bottle body of the bottle product prepared using the bottle embryo has certain antibacterial efficiency, and the inside of the bottle has high antibacterial efficiency.

Description

Technical Field

[0001] The invention belongs to the field of polymer materials, and in particular relates to an antibacterial plastic bottle embryo for food and a preparation method thereof. Background Art

[0002] Maintaining the safety of food and drugs is to maintain the window to human health. Before food and drugs pass quality inspection and enter the market, they are mainly stored and transported in corresponding containers. An important factor affecting whether the food and drugs in the container can remain safe and sterile when leaving the factory is the need for a safe and antibacterial container.

[0003] For plastic bottles, antibacterial agents are added to the material components of the plastic profile molding to prepare plastic bottles with antibacterial properties.

[0004] At present, the widely used antibacterial agents are mainly divided into inorganic antibacterial materials, organic antibacterial materials, natural antibacterial materials, polymer antibacterial materials, etc.

[0005] Among them, nano-scale silver-based inorganic antibacterial materials are the most widely used. Silver ion antibacterial agents are highly safe, heat-resistant, and non-volatile. However, the accumulation and migration of silver ions or metal ions can also cause certain life and safety problems. When silver is enriched to a higher concentration, it is more harmful to humans and mammals, and may enter mitochondria, embryos, liver, and circulatory system through breathing. In addition, excessive silver ions will make it difficult to adjust the appearance color of the product.

[0006] Organic antibacterial materials mainly include imidazoles, pyridines, isothiazolinones, phenols, quaternary ammonium salts, phenols, acylanilides, bisguanidines, vanillin or ethyl vanillin compounds. However, the safety of their corresponding decomposition products also needs to be considered.

[0007] Natural antibacterial materials are mainly plant extracts, including chitosan and its derivatives, etc. However, their application efficiency is not high, and the preparation process is limited due to their own characteristics.

[0008] Polymer antibacterial materials mainly include polypyrazole, polyhexamethylene guanidine hydrochloride, polystyrene caprolactone, multivalent salt polymer antibacterial agents, etc., and their comprehensive properties are more stable.

[0009] In practical applications, it is necessary to consider the cost and effect of various antimicrobial agents and their preparation processes. In this application, the cost of the antimicrobial agent, the preparation process of its attachment, and the final antimicrobial effect of the material are comprehensively considered to select a composite antimicrobial agent. Summary of the invention

[0010] In order to solve the problems existing in the above background technology, the present application aims to prepare an antibacterial plastic bottle preform for food and its preparation method. The bottle preform is mainly composed of polyethylene terephthalate (PET) as the main material, chitosan-modified polypropylene fiber as the antibacterial masterbatch, dendritic quaternary ammonium salt polymer antibacterial agent, isooctyl thioglycolate, carbonate and other components. The bottle preform has excellent antibacterial properties, as well as good comprehensive mechanical properties and processing and forming properties.

[0011] One of the purposes of the present application is to select PET as the main material and mix it with polypropylene fiber modified by chitosan. Both PET and PP are food-grade plastic materials, and chitosan can also be a bio-friendly material, which further enhances the biocompatibility of food-grade materials. In addition, the use of chitosan-modified PP antibacterial material can make the bottle blank and its derivative products have certain antibacterial properties in terms of materials. In addition, PP can reduce the sensitivity of PET to moisture, so as to improve the molding process of PET during thermoplastic molding.

[0012] Another purpose of the present application is to select chitosan-modified polypropylene fiber as an antibacterial masterbatch and dendritic quaternary ammonium salt polymer antibacterial agent as two antibacterial agents, and adjust the dosage and method of use of the two to prepare a bottle embryo that has both cost and high antibacterial properties. When using two antibacterial agents, the two antibacterial agents are not mixed in one pot, but the materials are released through the mold during the injection molding process of the bottle embryo. A double-layer bottle embryo is prepared using a double-layer mold, and the chitosan-modified polypropylene fiber antibacterial masterbatch is mixed into the main material of the bottle embryo and placed in the outer injection mold; the dendritic quaternary ammonium salt polymer antibacterial agent is mixed into the main material of the first injection and placed in the inner injection mold, and the double-layer bottle embryo required by the present application is formed by simultaneous injection molding through the double-layer mold.

[0013] Therefore, the content of chitosan-modified polypropylene fiber as antibacterial masterbatch is at least 2.5 times that of dendritic quaternary ammonium salt polymer antibacterial agent, and the bottle preform is injection molded in a double-layer injection molding form. The bottle preform prepared according to the above preparation has high antibacterial properties, and the bottle body of the bottle product prepared using the bottle preform has certain antibacterial properties, and the inner side of the bottle of the bottle product containing the goods has more stable and efficient antibacterial properties.

[0014] Another object of the present application is to add isooctyl thioglycolate as a heat stabilizer during injection molding, so that the PET bottle embryo has better compatibility and processing adaptability, and the PET plastic bottle material is not easily decomposed by heat.

[0015] Another purpose of the present application is to add carbonate as a nucleating agent. This is because PET has a slow crystallization rate and a long molding cycle. Nucleating agents and crystallization accelerators are added to increase its crystallization rate, reduce mold temperature, and improve PET processing and molding.

[0016] In the first aspect of the present application, an antibacterial plastic bottle embryo for food is provided, the bottle embryo comprising polyethylene terephthalate (PET), chitosan-modified polypropylene fiber antibacterial masterbatch, dendritic quaternary ammonium salt polymer antibacterial agent, isooctyl thioglycolate, carbonate and other additive components;

[0017] The chitosan-modified polypropylene fiber antibacterial masterbatch is added in the outer layer injection molding process; the chitosan-modified polypropylene fiber antibacterial masterbatch is added in the inner layer injection molding process in combination with the dendritic quaternary ammonium salt polymer antibacterial agent.

[0018] The dendritic quaternary ammonium salt polymer antibacterial agent has the characteristics of high efficiency, low toxicity, good thermal stability, not easily affected by pH changes, and easy to use. The cation mainly adsorbs negatively charged bacteria through electrostatic force, hydrogen bond force, and hydrophobic binding between surfactant molecules and protein molecules, and accumulates on the cell wall to produce a chamber resistance effect, resulting in bacterial growth inhibition and death. In this application, the bottle embryo is prepared by a double-layer composite injection molding process, which is actually to distinguish the distribution of the antibacterial agent in the bottle embryo through the process to achieve an effective antibacterial effect inside the bottle.

[0019] Moreover, the compounding of natural antimicrobial agents with chitosan can make the preform have lower antimicrobial side effects, and the chitosan-modified PP antimicrobial agent can properly balance the cost of the dendritic quaternary ammonium salt polymer antimicrobial agent.

[0020] In the application, dodecyltrimethylammonium chloride is added to the components. Dodecyltrimethylammonium chloride uses the characteristics of surfactants to absorb moisture in the air, polarize itself, and form an extremely thin conductive layer on the surface of the material, forming a static electricity leakage channel, making it difficult for static electricity to accumulate on the surface of PET plastic bottles, thereby reducing the safety hazards of PET plastic bottles during transportation and use.

[0021] Furthermore, the weight ratio of the components of the plastic bottle embryo is: 95-98 parts of polyethylene terephthalate (PET), 5-6 parts of chitosan-modified polypropylene fiber antibacterial masterbatch, 1.8-2 parts of dendritic quaternary ammonium salt polymer antibacterial agent, 0.3-0.4 parts of isooctyl thioglycolate, 0.1-0.15 parts of carbonate and 0.4-0.6 parts of other additive components.

[0022] Furthermore, the weight proportion of the chitosan-modified polypropylene fiber antibacterial masterbatch is 2.5-3 times that of the dendritic quaternary ammonium salt polymer antibacterial agent.

[0023] Furthermore, the chitosan content in the chitosan-modified polypropylene fiber antibacterial masterbatch is 15%-18%. The PP antibacterial masterbatch is customized by the manufacturer according to the functional requirements of the bottle embryo.

[0024] Furthermore, the other components may also include: antioxidants, food coloring, and lubricants.

[0025] Furthermore, the antibacterial chitosan-modified polypropylene fiber antibacterial masterbatch is added in the outer layer molding process together with the polyethylene terephthalate main material; the dendritic quaternary ammonium salt polymer antibacterial agent is superimposed in the inner layer injection molding process based on the components of the first injection molding process; wherein the ratio of the outer layer injection molding thickness to the outer layer injection molding thickness is (1.8-2):0.5.

[0026] Using a double-layer composite injection molding machine, two similar raw materials are mixed (only the content and type of the antibacterial agent are changed), blended, melted, and transported to corresponding internal and external material delivery channels, and then injection molded through a double-layer mold.

[0027] In a second aspect of the present application, a method for preparing an antibacterial plastic bottle embryo for food is provided, the method comprising the following steps:

[0028] S1: Raw material pretreatment: The required PET raw materials are dried under negative pressure;

[0029] S2: Raw material melting: Add the raw material granules, chitosan-modified polypropylene fiber antibacterial masterbatch, isooctyl thioglycolate, carbonate and other additive components in S1 into the outer material barrel; add the raw material granules, chitosan-modified polypropylene fiber antibacterial masterbatch, dendritic quaternary ammonium salt polymer antibacterial agent, isooctyl thioglycolate, carbonate and other additive components in S1 into the inner material barrel; set the barrel melting temperature to between 200-230°C;

[0030] S3: Injection molding: The molten plastic melt is processed into a double-layer bottle embryo through an injection molding compound process in a double-material injection molding machine; the temperature of the double-layer mold of the double-material injection molding machine is controlled to be 180-220°C.

[0031] Since PET is water-sensitive, the PET raw material needs to be dried at about 80°C under negative pressure before melting to remove moisture and dust.

[0032] In the injection molding pipeline, the temperature is mainly coordinated with the melt molding temperature of PET, and the temperature control is not limited to multiple sections.

[0033] Furthermore, the ratio of the outer layer injection molding thickness to the outer layer injection molding thickness is (1.8-2):0.5.

[0034] Furthermore, in the inner barrel, the weight fraction ratio of the chitosan-modified polypropylene fiber antibacterial masterbatch to the dendritic quaternary ammonium salt polymer antibacterial agent in the barrel is 1:(1.5-1.8).

[0035] In the third aspect of the present application, an application of an antibacterial plastic bottle embryo for food is provided, and the bottle embryo is prepared into an antibacterial plastic bottle by variable pressure blow molding; wherein the blowing temperature is 25-80°C, the first stage blowing pressure is 2.5-3MPa, and the blowing pressure is 1-1.5MPa.

[0036] Beneficial effects of the present invention:

[0037] The present application uses PET material and PP antibacterial masterbatch as the main materials, which can prepare food-grade plastic materials, among which PP can also improve the processing and forming properties of PET; chitosan-modified polypropylene fiber antibacterial masterbatch and dendritic quaternary ammonium salt polymer antibacterial agent are selected, and the biofriendliness of chitosan is consistent with the quaternary ammonium salt polymer antibacterial agent, which can make the profile have antibacterial properties; further, chitosan and quaternary ammonium salt polymer antibacterial agent are added to the inner layer as a composite antibacterial agent, which can ensure the excellent antibacterial properties of the bottle and the contents and reduce costs; further, a double-layer composite injection molding machine is used to prepare a bottle embryo with an antibacterial agent distribution by double-layer injection molding, and then the bottle embryo is blow-molded into a bottle material with high-efficiency antibacterial properties inside. This preparation method is simpler and more efficient. DETAILED DESCRIPTION

[0038] In order to facilitate a better understanding of the present invention, the following examples are used to illustrate the present invention. These examples belong to the protection scope of the present invention, but do not limit the protection scope of the present invention.

[0039] An antibacterial plastic bottle embryo for food and a PET antibacterial plastic bottle are prepared by the following steps:

[0040] Raw material pretreatment: The PET raw materials are subjected to centralized negative pressure drying to remove moisture and impurities; the drying temperature is 70°C.

[0041] Raw material melting:

[0042] (1) adding the pretreated raw material particles, chitosan-modified polypropylene fiber antibacterial masterbatch, isooctyl thioglycolate, carbonate and other additive components into the outer material barrel;

[0043] (2) Add the pretreated raw material particles, chitosan-modified polypropylene fiber antibacterial masterbatch, dendritic quaternary ammonium salt polymer antibacterial agent, isooctyl thioglycolate, carbonate and other additive components into the inner material barrel.

[0044] Set the barrel melt temperature to between 200°C.

[0045] Injection molding: The molten plastic melt is processed into a double-layer bottle embryo through an injection molding compound process in a double-material injection molding machine. The temperature of the double-layer mold of the double-material injection molding machine is controlled to be 190°C.

[0046] Blow molding: The antibacterial plastic bottles were prepared by variable pressure blow molding; the blowing temperature was 80°C, the first blowing pressure was 2.5 MPa, and the blowing pressure was 1.5 MPa.

[0047] Example 1: Prepare an antibacterial plastic bottle for food according to the following weight ratio:

[0048] 95 parts of polyethylene terephthalate (PET), 5 parts of chitosan-modified polypropylene fiber antibacterial masterbatch, 1.8 parts of dendritic quaternary ammonium salt polymer antibacterial agent, 0.3 parts of isooctyl thioglycolate, 0.1 parts of carbonate, and 0.1 parts of antioxidant.

[0049] The ratio of the outer layer thickness to the outer layer thickness of the bottle embryo is 2:0.5, and the weight ratio of the chitosan-modified polypropylene fiber antibacterial masterbatch and the dendritic quaternary ammonium salt polymer antibacterial agent of the inner layer mold material is 1:1.8.

[0050] Example 2: Prepare an antibacterial plastic bottle for food according to the following weight ratio:

[0051] 95 parts of polyethylene terephthalate (PET), 6 parts of chitosan-modified polypropylene fiber antibacterial masterbatch, 0.3 parts of isooctyl thioglycolate, 0.1 parts of carbonate, and 0.1 parts of antioxidant.

[0052] The bottle embryo is prepared by one-step injection molding, and the antibacterial plastic bottle is formed by blow molding of the bottle embryo.

[0053] Example 3: Prepare an antibacterial plastic bottle for food according to the following weight ratio:

[0054] 95 parts of polyethylene terephthalate (PET), 2 parts of dendritic quaternary ammonium salt polymer antibacterial agent, 0.3 parts of isooctyl thioglycolate, 0.1 parts of carbonate, and 0.1 parts of antioxidant.

[0055] The ratio of the outer layer thickness to the outer layer thickness of the bottle embryo is 2:0.5, wherein the dendritic quaternary ammonium salt polymer antibacterial agent is added only to the inner layer mold material.

[0056] Example 4: Prepare an antibacterial plastic bottle for food according to the following weight ratio:

[0057] 95 parts of polyethylene terephthalate (PET), 6 parts of chitosan-modified polypropylene fiber antibacterial masterbatch, 1 part of dendritic quaternary ammonium salt polymer antibacterial agent, 0.3 parts of isooctyl thioglycolate, 0.1 parts of carbonate, and 0.1 parts of antioxidant.

[0058] The ratio of the outer layer thickness to the outer layer thickness of the bottle embryo is 2:0.5, and the weight ratio of the chitosan-modified polypropylene fiber antibacterial masterbatch and the dendritic quaternary ammonium salt polymer antibacterial agent of the inner layer mold material is 1.2:1.

[0059] Example 5: Prepare an antibacterial plastic bottle for food according to the following weight ratio:

[0060] 95 parts of polyethylene terephthalate (PET), 3 parts of chitosan-modified polypropylene fiber antibacterial masterbatch, 1.2 parts of dendritic quaternary ammonium salt polymer antibacterial agent, 0.3 parts of isooctyl thioglycolate, 0.1 parts of carbonate, and 0.1 parts of antioxidant.

[0061] The ratio of the outer layer thickness to the outer layer thickness of the bottle embryo is 2:0.5, and the weight ratio of the chitosan-modified polypropylene fiber antibacterial masterbatch and the dendritic quaternary ammonium salt polymer antibacterial agent of the inner layer mold material is 1:2.

[0062] The plastic bottles of the above-mentioned embodiments were tested for antibacterial properties. The antibacterial performance test was conducted according to QB / T2591-2003A. The test bacteria used were: Escherichia coli (ATCC 25922) and Staphylococcus aureus (ATCC6538).

[0063] Antibacterial test results table:

[0064]

[0065] As can be seen from the above table, the antibacterial plastic bottle embryo for food provided by this application and the plastic bottle prepared therefrom have better antibacterial properties than those of other embodiments 2-5, compared with Example 1. Moreover, the antibacterial property of the bottle body can be maintained at about 95%, and the antibacterial property inside the bottle can be as high as 98%. Furthermore, in actual tests, after 100 days, the antibacterial property of the bottle body and the inside of the bottle can be maintained at more than 90% of the first test, and the subsequent antibacterial property is in a relatively stable state.

[0066] It can also be seen from the above embodiments that the proportion of the polymer antibacterial agent maintained in the inner layer can also ensure that the antibacterial property in the bottle reaches more than 90%, and since the chitosan antibacterial agent is added in the form of antibacterial masterbatch, its content has a smaller effect than that of the polymer antibacterial agent, thus indicating the efficient application of the polymer antibacterial agent.

[0067] The above shows and describes the basic principles and main features of the present application and the advantages of the present application. Those skilled in the art should understand that the present application is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present application. Without departing from the spirit and scope of the present invention, the present application may have various changes and improvements, and these changes and improvements fall within the scope of the present invention to be protected. The scope of protection claimed in the present application is defined by the attached claims and their equivalents.

Claims

1. An antibacterial plastic preform for food, characterized in that: The plastic bottle embryo at least comprises the following components: polyethylene terephthalate, chitosan-modified polypropylene fiber antibacterial masterbatch, dendritic quaternary ammonium salt polymer antibacterial agent, isooctyl thioglycolate, carbonate and other additive components; wherein the weight proportions of the plastic bottle embryo components are: 95-98 parts of polyethylene terephthalate, 5-6 parts of chitosan-modified polypropylene fiber antibacterial masterbatch, 1.8-2 parts of dendritic quaternary ammonium salt polymer antibacterial agent, 0.3-0.4 parts of isooctyl thioglycolate, 0.1-0.15 parts of carbonate and 0.4-0.6 parts of other additive components; the weight proportion of the chitosan-modified polypropylene fiber antibacterial masterbatch is 2.5-3 times that of the dendritic quaternary ammonium salt polymer antibacterial agent; the chitosan content in the chitosan-modified polypropylene fiber antibacterial masterbatch is 15%-18%; The chitosan-modified polypropylene fiber antibacterial masterbatch is added into the outer layer injection mold; the chitosan-modified polypropylene fiber antibacterial masterbatch is added into the inner layer injection mold together with the dendritic quaternary ammonium salt polymer antibacterial agent.

2. The antibacterial plastic preform for food according to claim 1, characterized in that: The other additive components also include: antioxidants, food coloring and lubricants.

3. The antibacterial plastic preform for food according to claim 1, characterized in that: The antibacterial chitosan-modified polypropylene fiber antibacterial masterbatch is added in the outer layer injection molding process, together with the polyethylene terephthalate main material; the dendritic quaternary ammonium salt polymer antibacterial agent is superimposed in the inner layer injection molding process based on the components of the inner layer injection molding process; Among them, the ratio of the outer layer injection molding thickness to the inner layer injection molding thickness is (1.8-2): 0.

5.

4. A method for preparing an antibacterial plastic bottle embryo for food according to claim 1, characterized in that: The method comprises the following steps: S1: Raw material pretreatment: subjecting the required polyethylene terephthalate raw material to negative pressure drying; S2: Raw material melting: Add the raw material granules, chitosan-modified polypropylene fiber antibacterial masterbatch, isooctyl thioglycolate, carbonate and other additive components in S1 into the outer material barrel; add the raw material granules, chitosan-modified polypropylene fiber antibacterial masterbatch, dendritic quaternary ammonium salt polymer antibacterial agent, isooctyl thioglycolate, carbonate and other additive components in S1 into the inner material barrel; set the barrel melting temperature to between 200-230°C; S3: Injection molding: The molten plastic melt is processed into a double-layer bottle embryo through an injection molding compound process in a double-material injection molding machine; the temperature of the double-layer mold of the double-material injection molding machine is controlled to be 180-220°C.

5. A method for preparing an antibacterial plastic bottle embryo for food according to claim 4, characterized in that: The ratio of the outer layer injection molding thickness to the inner layer injection molding thickness is (1.8-2): 0.

5.

6. A method for preparing an antibacterial plastic bottle embryo for food according to claim 4, characterized in that: In the inner barrel, the weight ratio of the chitosan-modified polypropylene fiber antibacterial masterbatch to the dendritic quaternary ammonium salt polymer antibacterial agent in the barrel is 1: (1.5-1.8).

7. An application of the antibacterial plastic preform for food as claimed in claim 1, characterized in that: The bottle embryo is subjected to variable pressure blow molding to prepare an antibacterial plastic bottle; wherein the blowing temperature is 25-80° C., the first stage blowing pressure is 2.5-3 MPa, and the blowing pressure is 1-1.5 MPa.

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