Method for preparing PET fabric moisture absorption antibacterial finishing agent based on waste plastic recovery raw materials

Abstract

The invention discloses a method for preparing a PET fabric moisture absorption antibacterial finishing agent based on waste plastic recovery raw materials. The method comprises the following steps: S1, carrying out sugar alcoholysis on waste plastic PET; s2, synthesizing an NPn molecular chain with an isocyanate end group; and S3, synthesizing a final product NPnB-Cm. The invention solves the problems that the PET moisture absorption and bacteriostasis modification effect is poor in durability, the hand feeling and mechanical properties of the modified fabric are reduced, the synthesis process of the PET modification finishing agent is complicated, and the industrial wet finishing method is easy to cause environmental pollution and chemical waste, and the like, and combines the cation-pi interaction and hydrogen bond adhesion mechanism in marine mussel protein. The PET textile finishing agent which contains a bionic supramolecular structure, is environment-friendly and has moisture absorption and antibacterial functions is prepared.

Description

Technical Field

[0001] The invention relates to the technical field of textile materials, in particular to a method for preparing a PET fabric moisture absorption and antibacterial finishing agent based on recycled waste plastic raw materials. Background Art

[0002] With the development of modern science and technology and the popularization of health awareness, textile materials with moisture and heat management and antibacterial protection functions are becoming increasingly important. Polyester (PET), as one of the important new functional fabric substrates, has the characteristics of large output, low cost, good mechanical properties and flexible processing. However, PET is inherently hydrophobic, has a stable chemical structure and lacks modified groups on the surface, which makes the fabric difficult to absorb moisture and perspiration and difficult to modify. Conventional functional modification additives are difficult to adhere to the fabric for a long time, and are prone to cause environmental pollution and chemical waste. Therefore, the demand for PET moisture absorption and antibacterial modification is becoming increasingly urgent. At present, the main technologies for modifying PET fabrics at home and abroad are: breaking the PET molecular chain structure through pre-treatment methods such as alkali solution, plasma, radiation etching or enzyme hydrolysis surface to produce reactive groups, and then changing the morphology and structure of the fiber surface through electrochemical reaction, surface grafting of functional groups, electrospinning, spraying or impregnation to give PET fabric functionality.

[0003] The current PET has the following problems:

[0004] 1. The hygroscopic and antibacterial modification effect of PET is not long-lasting. After multiple washings, the hydrophilicity and antibacterial properties will drop significantly;

[0005] 2. The feel of PET and the mechanical properties of the fabric change, affecting the overall quality of the fabric;

[0006] 3. The process of synthesizing functional modifiers is complex and the conditions are harsh;

[0007] 4. The conventional wet finishing modification method of PET fabric requires the additional use of a large amount of additives, which can easily cause environmental pollution and waste of chemicals.

[0008] The present invention aims to solve the problems of poor durability of PET hygroscopic and antibacterial modification effect, decreased hand feel and mechanical properties of fabric after modification, complex synthesis process of PET modified finishing agent, and environmental pollution and chemical waste caused by industrial wet finishing method. To this end, we propose to use the recycled product of waste plastic PET as raw material, combined with the cation-π interaction and hydrogen bond adhesion mechanism in marine mussel protein, to prepare a PET fabric finishing agent with bionic supramolecular structure, environmental protection and hygroscopic and antibacterial function. Summary of the invention

[0009] The object of the present invention is to provide a method for preparing a hygroscopic and antibacterial finishing agent for PET fabric based on recycled raw materials from waste plastics.

[0010] To achieve the above object, the present invention provides the following technical solutions:

[0011] The present invention proposes a method for preparing a PET fabric moisture-absorbing and antibacterial finishing agent based on recycled waste plastic raw materials, comprising the following steps:

[0012] S1. Alcohol hydrolysis of waste plastic PET:

[0013] Under a nitrogen atmosphere, EG, cleaned waste plastic bottle PET fragments and a catalyst are added to a three-necked flask, and reacted at a temperature and time. After the reaction is completed, the product in the flask is filtered, and the solid on the filter paper is rinsed with boiling deionized water for many times, and the filtrate is collected and placed in a refrigerator for recrystallization to obtain needle-shaped crystals. Finally, the crystals are washed with deionized water for many times, and then placed in a vacuum oven for drying to obtain bis(hydroxyethyl) terephthalate (BHET), a raw material for the degradation of waste plastic bottle PET;

[0014] S2. Synthesis of NPs with isocyanate end groups n Molecular chain

[0015] Under the protection of N2, PEG is added into a three-necked flask, the flask is moved to an oil bath, the temperature is raised to 110°C, the reaction is carried out for a period of time, the water in the PEG is fully removed, then the temperature is lowered to 60-80°C, and then a certain amount of aliphatic or cycloaliphatic isocyanate and dibutyltin dilaurate (DBTDL) are added into the flask, the reaction is continued for a period of time, and the viscosity of the system in the flask is adjusted with an organic solvent;

[0016] S3. Synthesis of the final product NP n BC m

[0017] After the reaction in step S2 is completed, BHET and cationic monomer are added to the flask and the reaction is continued at the temperature for a period of time to obtain the final product NP n BC m (n represents the molecular weight of PEG; m represents the serial number of the cationic monomer).

[0018] Preferably, in step S1, the ratio of EG to PET is from 3:1 to 10:1; the catalyst is one of zinc acetate or tetrabutyl titanate, and the mass fraction of the catalyst is 2 to 6wt%; the reaction temperature is 170 to 210°C; the reaction time is 3 to 8h; and the temperature of the vacuum oven is 60 to 80°C.

[0019] Preferably, in step S2, the molecular weight of PEG is 500-2000; the time for removing water from PEG is 1-3 hours; the mass percentage of DBTDL is 1.5-5wt%; the reaction time is 2-5 hours; and the organic solvent for adjusting the viscosity of the system includes N,N-dimethylformamide and acetone.

[0020] Preferably, in step S3, the reaction temperature is 50-80° C. and the reaction time is 3-24 h.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. Using the recycled raw materials of waste plastic PET as the moisture-absorbing and antibacterial finishing agent for PET fabrics reduces the pollution of waste plastics to the environment and the technology is more environmentally friendly;

[0023] 2. It can realize multifunctional modification of PET fabric at the same time;

[0024] 3. Based on the marine mussel cation-π adhesion mechanism and the ability of the isocyanate group to form hydrogen bonds with the substrate surface, the combination of dual supramolecular effects enables the finishing agent to adhere more firmly to the PET fabric surface and have better durability;

[0025] 4. The use of recycled raw materials from waste plastic PET to prepare finishing agents reduces production costs. At the same time, the preparation process is simple and does not require complex equipment and reaction conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The molecular structures of various cationic monomers and aliphatic and alicyclic isocyanate molecules in the present invention;

[0027] Figure 2 It is a schematic diagram of the reaction process of synthesizing the moisture absorption and antibacterial finishing agent for PET fabrics of the present invention;

[0028] Figure 3 It is a schematic diagram of the process of modifying PET fabric with a finishing agent in the present invention. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] The present invention aims to solve the problems of poor durability of PET hygroscopic and antibacterial modification effect, decreased hand feel and mechanical properties of fabric after modification, complex synthesis process of PET modified finishing agent, and environmental pollution and chemical waste caused by industrial wet finishing method. To this end, we propose to use the recycled product of waste plastic PET as raw material, combined with the cation-π interaction and hydrogen bond adhesion mechanism in marine mussel protein, to prepare a PET fabric finishing agent with bionic supramolecular structure, environmental protection and hygroscopic and antibacterial function.

[0031] PET molecules are rich in phenyl groups and have a large number of π bonds. Inspired by the cation-π bond supramolecular interaction in the adhesion mechanism of marine mussels, combined with the commonly used disperse dyeing method for wet finishing of PET fabrics, a linear hydrophobic phenyl / heterocyclic small molecule structure is designed in the finishing agent. This design makes the molecular structure of the finishing agent similar to that of PET fabrics, which is conducive to the finishing agent entering the gaps of PET fibers. In addition, with the help of intermolecular forces such as hydrophobic interactions and hydrogen bonds, the bonding strength between the finishing agent and PET can be enhanced.

[0032] In order to effectively utilize the recycled raw materials of waste plastic PET for PET fabric, the present invention uses bis(hydroxyethyl) terephthalate (BHET), a product of sugar alcohol hydrolysis of waste plastic PET, as a raw material, and uses molecules containing isocyanate groups as linkers. At the same time, a cationic monomer with antibacterial function is introduced by combining the cation-π mechanism, and polyethylene glycol (PEG) is introduced into the molecular chain to improve the softness and hygroscopicity of the molecular chain, thereby synthesizing the biomimetic supramolecular chain NP. n BC m , ultimately giving the synthetic finishing agent the ability to absorb moisture and resist bacteria.

[0033] The present invention combines the recycled raw materials of waste plastic PET with the cationic-π adhesion mechanism, and at the same time, by means of the characteristic of isocyanate forming hydrogen bonds with most substrate surfaces, the dual supramolecular action is used to enhance the bonding strength between the bionic supramolecular finishing agent and the fabric. Then, the synthesized finishing agent is purified by rotary evaporation, washing and other methods, and then dissolved by a solvent to prepare solutions of different concentrations. With PET fabric as the substrate, finishing agents of different concentrations are applied to the PET fabric by a disperse dyeing method, and then the finished PET fabric is rolled dry by a rolling mill, and finally the composite system composed of the bionic supramolecular coating and the PET fabric is baked and shaped in an oven, thereby giving the PET fabric functions such as moisture absorption and antibacterial.

[0034] like Figure 1 As shown, Figure 1 (a) is a schematic diagram of the molecular structure of several cationic monomers used in the present invention; (b) is a schematic diagram of the molecular structure of several aliphatic and alicyclic isocyanates. Figure 1 The cationic monomers listed in a (C m ) can be selected from F, Cl, Br and trifluoromethanesulfonamide.

[0035] The details are as follows:

[0036] (I) First step: glycolysis of waste plastic PET

[0037] Under nitrogen atmosphere, a certain amount of EG, cleaned waste plastic bottle PET fragments and catalyst are added to a three-necked flask and reacted at a certain temperature and time. After the reaction is completed, the product in the flask is filtered, and the solid on the filter paper is rinsed with boiling deionized water for many times. The filtrate is collected and placed in a refrigerator for recrystallization to obtain needle-shaped crystals. Finally, the crystals are washed with deionized water many times, and then placed in a vacuum oven for drying to obtain the raw material bis(hydroxyethyl) terephthalate (BHET) for the degradation of waste plastic bottle PET.

[0038] (II) Step 2: Synthesis of NPs with isocyanate end groups n Molecular chain

[0039] Under the protection of N2, a certain amount of PEG is added to a three-necked flask, the flask is moved to an oil bath, the temperature is raised to 110°C, and the reaction is carried out for a period of time to fully remove the water in the PEG. Subsequently, the temperature is lowered to 60-80°C, and then a certain amount of aliphatic or cycloaliphatic isocyanate and dibutyltin dilaurate (DBTDL) are added to the flask, the reaction is continued for a period of time, and the viscosity of the system in the flask is adjusted with an organic solvent.

[0040] (III) Step 3: Synthesis of the final product NP n BC m

[0041] After the above reaction is completed, a certain amount of BHET and cationic monomer are added to the flask, and the reaction is continued for a period of time at a certain temperature to obtain the final product NP n BC m (n represents the molecular weight of PEG; m represents the serial number of the cationic monomer).

[0042] In step (I), the ratio of EG to PET is from 3:1 to 10:1; the catalyst is zinc acetate or tetrabutyl titanate, and the mass fraction of the catalyst is 2 to 6 wt% (based on the mass of PET); the reaction temperature is 170 to 210°C; the reaction time is 3 to 8 hours; and the temperature of the vacuum oven is 60 to 80°C.

[0043] The molecular weight of PEG in step (II) is 500-2000; the time for removing water from PEG is 1-3 hours; the mass percentage of DBTDL is 1.5-5wt% (based on the mass of the hydroxyl-containing raw material in the system); the reaction time is 2-5 hours; the organic solvent for adjusting the viscosity of the system includes N,N-dimethylformamide, acetone, etc.

[0044] The reaction temperature in step (III) is 50-80°C; the reaction time is 3-24h.

[0045] The ratio of materials in steps (II) and (III) is put into the reaction flask as shown in Table 1.

[0046] Serial number NCO <![CDATA[PEG n ]]> BHET <![CDATA[C m ]]> 1 3 1 1 1 2 4 2 1 1 3 4 1 2 1 4 4 1 1 2 5 4 1 1 1

[0047] Table 1

[0048] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0049] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A method for preparing a hygroscopic and antibacterial finishing agent for PET fabric based on recycled raw materials from waste plastics, characterized in that: The following steps are involved: S1. Alcohol hydrolysis of waste plastic PET: Under a nitrogen atmosphere, EG, cleaned waste plastic bottle PET fragments and a catalyst are added to a three-necked flask, and reacted at a temperature and time. After the reaction is completed, the product in the flask is filtered, and the solid on the filter paper is rinsed with boiling deionized water for many times, and the filtrate is collected and placed in a refrigerator for recrystallization to obtain needle-shaped crystals. Finally, the crystals are washed with deionized water for many times, and then placed in a vacuum oven for drying to obtain bis(hydroxyethyl) terephthalate (BHET), a raw material for the degradation of waste plastic bottle PET; S2. Synthesis of NPs with isocyanate end groups n Molecular chain: Under the protection of N2, PEG is added into a three-necked flask, the flask is moved to an oil bath, the temperature is raised to 110°C, the reaction is carried out for a period of time, the water in the PEG is fully removed, then the temperature is lowered to 60-80°C, and then a certain amount of aliphatic or cycloaliphatic isocyanate and dibutyltin dilaurate (DBTDL) are added into the flask, the reaction is continued for a period of time, and the viscosity of the system in the flask is adjusted with an organic solvent; S3. Synthesis of the final product NP n BC m : After the reaction in step S2 is completed, BHET and cationic monomer are added to the flask and the reaction is continued at the temperature for a period of time to obtain the final product NP n BC m (n represents the molecular weight of PEG; m represents the serial number of the cationic monomer).

2. The method for preparing a hygroscopic and antibacterial finishing agent for PET fabric based on recycled waste plastics according to claim 1, characterized in that: In the step S1, the ratio of EG to PET is from 3:1 to 10:1; the catalyst is one of zinc acetate or tetrabutyl titanate, and the mass fraction of the catalyst is 2 to 6 wt%; the reaction temperature is 170 to 210° C.; the reaction time is 3 to 8 hours; and the temperature of the vacuum oven is 60 to 80° C.

3. The method for preparing a hygroscopic and antibacterial finishing agent for PET fabric based on recycled waste plastics according to claim 1, characterized in that: In the step S2, the molecular weight of PEG is 500-2000; the time for removing water from PEG is 1-3 hours; the mass percentage of DBTDL is 1.5-5wt%; the reaction time is 2-5 hours; and the organic solvent for adjusting the viscosity of the system includes N,N-dimethylformamide and acetone.

4. The method for preparing a hygroscopic and antibacterial finishing agent for PET fabric based on recycled waste plastics according to claim 1, characterized in that: In step S3, the reaction temperature is 50-80° C. and the reaction time is 3-24 hours.

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