A biomass low-carbon flame-retardant PET material and its preparation method

Abstract

The present invention discloses a biomass-based low-carbon flame-retardant PET material and its preparation method, belonging to the field of flame-retardant PET technology. The material comprises the following components by weight: 15 to 70 parts PET resin, 10 to 20 parts phosphorylated chitosan derivative, 30 to 40 parts glass fiber, 1 to 5 parts lubricant, 0.5 to 1 part antioxidant, and 0.3 to 1 part coupling agent. By introducing phosphorus-containing groups into the chitosan molecular chain, the present invention forms a phosphorylated chitosan derivative without destroying the chitosan molecular framework, thereby improving the flame retardancy and solubility of the chitosan. This improves the flame retardancy of the biomass-based low-carbon flame-retardant PET, while also exhibiting antibacterial properties. The material has a wide range of applications and is highly safe.

Description

Technical Field

[0001] The present invention relates to the technical field of flame-retardant PET, and in particular to a biomass low-carbon flame-retardant PET material and a preparation method thereof. Background Art

[0002] PET plastic, abbreviated as PET or PETP, means in Chinese: polyethylene terephthalate plastic, mainly including polyethylene terephthalate PET and polybutylene terephthalate PBT. Polyethylene terephthalate is also commonly known as polyester resin. It is a condensation product of terephthalic acid and ethylene glycol. Together with PBT, it is collectively called thermoplastic polyester, or saturated polyester.

[0003] PET, a thermoplastic engineering plastic, is widely used in household appliances due to its excellent dimensional stability, chemical resistance, and heat resistance. PET also exhibits excellent electrical insulation properties, particularly at high temperatures and high frequencies, making it popular in electrical and mechanical equipment within the household appliance sector. PET's primary components are C, H, and O, and its limiting oxygen index is less than 21%. PET's linear molecular chain produces significant droplets and large amounts of toxic fumes during combustion, potentially posing a threat to individuals and society. Therefore, developing flame-retardant PET materials and improving their flame retardancy can effectively prevent fires while reducing smoke release, droplets, and dripping during combustion, thereby minimizing the harm caused by fires and protecting residents' lives and property.

[0004] The blending method is one of the commonly used methods for developing flame-retardant PET. PET is blended with a flame retardant and then granulated at high temperature. Based on this idea, a variety of single flame retardants with different functions are prepared and modified into composite mixed flame retardants. Then, PET is modified by the blending method to develop various multifunctional flame-retardant PET. Among them, the modifiers of flame-retardant PET can be roughly divided into: halogen flame retardants and halogen-free flame retardants.

[0005] In the prior art, most traditional flame retardants used for PET flame retardancy are halogen-based flame retardants, primarily those containing chlorine and bromine as the primary flame-retardant active elements, such as brominated flame retardants. These halogen-based flame retardants not only produce harmful substances upon thermal decomposition, but are also subject to strict regulations regarding their use. Furthermore, they are non-renewable and can easily lead to excessive carbon emissions, causing environmental pollution. These issues make them unable to meet the environmental protection needs of modern society and fail to comply with national low-carbon environmental protection requirements. Summary of the Invention

[0006] The purpose of the present invention is to provide a biomass low-carbon flame-retardant PET material and a preparation method thereof, aiming to solve the problems of traditional halogen flame retardants being non-renewable, harmful to human health, and prone to causing excessive carbon emissions. To achieve the above objectives, the technical solutions adopted by the present invention are as follows:

[0007] In a first aspect, a biomass low-carbon flame-retardant PET material is provided, comprising the following components in parts by weight:

[0008] 15-70 parts of PET resin;

[0009] 10-20 parts of phosphorylated chitosan derivative;

[0010] 30-40 parts of glass fiber;

[0011] 1 to 5 parts of lubricant;

[0012] 0.5-1 part of antioxidant;

[0013] 0.3 to 1 part of coupling agent.

[0014] Wherein, the preparation of the phosphorylated chitosan derivative comprises the following steps:

[0015] S1, dissolving chitosan completely in methanesulfonic acid at a weight ratio of chitosan to methanesulfonic acid of 1:13 until no bubbles are left;

[0016] S2, adding phosphorus pentoxide at a weight ratio of 2:5 to chitosan at 20°C, and stirring under nitrogen for 3 h;

[0017] S3, after the reaction is completed, adding excess anhydrous ether to precipitate the product, and then filtering to obtain a solid precipitate, and washing the solid precipitate with acetone three times, anhydrous methanol three times, and anhydrous ether twice;

[0018] S4, after washing, vacuum drying was performed at room temperature for 10 h to obtain the phosphorylated chitosan derivative.

[0019] Because pure chitosan has a very weak flame retardant effect, chitosan must be modified and combined with polymers to form a flame-retardant composite material. By introducing phosphorus-containing groups into the chitosan molecular chain, we can form phosphorylated chitosan derivatives without destroying the chitosan molecular framework. This improves chitosan's flame retardancy and solubility, greatly broadening its application range. This chitosan is then blended with PET resin to produce a biomass-based, low-carbon, flame-retardant PET material.

[0020] During the combustion process, biomass low-carbon flame-retardant PET material will form a continuous, complete and dense carbon layer on the surface of the PET material. The formation of the carbon layer can isolate oxygen and heat sources, reduce smoke release, prevent the spread and propagation of flames, and delay molten droplets. It can not only prevent further degradation of the internal material, but also prevent heat transfer during the combustion process of the material, thereby improving the flame retardant properties of PET and having an antibacterial effect. It is particularly suitable for the field of home appliances.

[0021] As a further solution of the present invention, chitosan with a deacetylation degree of ≥95% is selected to prepare phosphorylated chitosan derivatives.

[0022] As a further solution of the present invention: the lubricant is one or a combination of two or more of silicone powder, montan wax, etc.

[0023] As a further solution of the present invention: the antioxidant is one or a combination of two or more of a phenolic primary antioxidant, a phosphite antioxidant, etc.

[0024] As a further solution of the present invention: the coupling agent is a silane coupling agent.

[0025] In a second aspect, a method for preparing a biomass low-carbon flame-retardant PET material is provided, comprising the following steps:

[0026] The PET resin and the phosphorylated chitosan derivative were dried separately; specifically, the PET resin was placed in an electric blast drying oven at 100° C. for 24 hours, and the phosphorylated chitosan derivative was placed in a vacuum drying oven at 40° C. for 10 hours;

[0027] PET, phosphorylated chitosan derivatives, glass fiber, lubricant, antioxidant, and coupling agent are uniformly mixed in a certain proportion, mixed for 10-30 minutes, and then extruded in a twin-screw extruder. The temperature range of the screw extruder is 190-220°C, and then a pelletizer is used to granulate the composite material to obtain biomass low-carbon flame-retardant PET.

[0028] The present invention has the following beneficial effects:

[0029] To address the issues of traditional halogen-based flame retardants being non-renewable, harmful to human health, and prone to excessive carbon emissions, the present invention provides a biomass-based low-carbon flame-retardant PET. This invention uses chitosan, a natural biomass material, to develop a low-carbon, environmentally friendly, and highly effective flame retardant. This is used to replace non-renewable raw materials to address the frequent fires and associated toxic hazards of PET materials during their use.

[0030] During the combustion process, biomass low-carbon flame-retardant PET material will form a continuous, complete and dense carbon layer on its surface. The formation of the carbon layer can isolate oxygen and heat sources, reduce smoke release, prevent the spread and propagation of flames, and delay molten droplets. It can not only prevent further degradation of the internal material, but also prevent heat transfer during the combustion process of the material, thereby improving the flame retardant properties of the PET material. It also has an antibacterial effect, a wide range of applications, and high safety. DETAILED DESCRIPTION

[0031] The present application is further described in detail below with reference to the following examples and comparative examples. Unless otherwise specified, the raw materials used in the examples and comparative examples can be obtained from commercial sources, and the equipment used is conventional equipment in the art.

[0032] The present invention provides a biomass low-carbon flame-retardant PET material comprising the following components in parts by weight:

[0033] 15-70 parts of PET resin, 10-20 parts of phosphorylated chitosan derivative, 30-40 parts of glass fiber (glass fiber ECS11-3.0-534A, monofilament diameter about 15 μm, purchased from China Jushi Co., Ltd.), 1-5 parts of lubricant, 0.5-1 parts of antioxidant, and 0.3-1 parts of coupling agent. The lubricant is one or a combination of silicone powder and montan wax, the antioxidant is one or a combination of two of a phenolic primary antioxidant (hindered phenol 1010, purchased from BASF, Germany) and a phosphite antioxidant (phosphite S-9228, purchased from Dover, USA), and the coupling agent is a silane coupling agent (silane coupling agent KH-570, industrial grade raw material).

[0034] Example 1

[0035] This embodiment provides a biomass low-carbon flame-retardant PET material, comprising the following components in parts by weight: 60 parts of PET resin, 10 parts of phosphorylated chitosan derivatives, 35 parts of glass fiber (glass fiber ECS11-3.0-534A, with a single fiber diameter of approximately 15 μm), 3 parts of lubricant (silicone powder), 0.5 parts of antioxidant (phosphite S-9228), and 1 part of coupling agent (silane coupling agent KH-570, industrial-grade raw material).

[0036] A method for preparing a biomass low-carbon flame-retardant PET material comprises the following steps:

[0037] Step 1, preparing a phosphorylated chitosan derivative, comprising:

[0038] S1, quantitatively weigh chitosan with a deacetylation degree of ≥95%, dissolve it in quantitatively weighed methanesulfonic acid (CH4O3S), with the weight ratio of chitosan to methanesulfonic acid being 1:13, and completely dissolve the chitosan until there are no bubbles;

[0039] S2, quantitatively add phosphorus pentoxide (P2O5) at 20°C, with the weight ratio of phosphorus pentoxide to chitosan being 2:5, and stir under nitrogen protection for 3 h;

[0040] S3, after the reaction is completed, anhydrous ether is added for precipitation, and then the solid precipitate is obtained by filtration, and the solid precipitate is washed with acetone three times, anhydrous methanol twice, and anhydrous ether twice in sequence;

[0041] S4, after washing, vacuum drying is performed at room temperature for 10 h to obtain the phosphorylated chitosan derivative.

[0042] Step 2: Add PET resin, the phosphorylated chitosan derivative obtained in step 1, glass fiber, lubricant, antioxidant, and coupling agent to a high-speed mixer and mix for 10-30 minutes. After the mixture is evenly mixed, add it to a twin-screw extruder for extrusion. The temperature range of the screw extruder is 190-220°C, the main engine speed is 300r / min, and the vacuum degree is -0.06MPa. After fully melted and composited, the composite material is granulated using a pelletizer to obtain a biomass low-carbon flame-retardant PET material.

[0043] Example 2

[0044] This embodiment provides a biomass low-carbon flame-retardant PET material, which is prepared according to the preparation method of Example 1. The formula includes the following components in parts by weight (unless otherwise specified, the raw materials in this embodiment and subsequent embodiments of the present invention are the same as those in Example 1):

[0045] 60 parts of PET resin, 15 parts of phosphorylated chitosan derivative, 35 parts of glass fiber (glass fiber ECS11-3.0-534A, monofilament diameter is about 15 μm), 3 parts of lubricant (silicone powder), 0.5 parts of antioxidant (phosphite S-9228), 1 part of coupling agent (silane coupling agent KH-570, industrial grade raw material).

[0046] Example 3

[0047] This embodiment provides a biomass low-carbon flame-retardant PET material, which is prepared according to the preparation method of Example 1. The formula includes the following components in parts by weight:

[0048] 60 parts of PET resin, 20 parts of phosphorylated chitosan derivative, 35 parts of glass fiber (glass fiber ECS11-3.0-534A, monofilament diameter is about 15 μm), 3 parts of lubricant (silicone powder), 0.5 parts of antioxidant (phosphite S-9228), 1 part of coupling agent (silane coupling agent KH-570, industrial grade raw material).

[0049] Comparative Example 1

[0050] A PET material provided in this embodiment is prepared according to the preparation method of Example 1, and the formula includes the following components in parts by weight:

[0051] 60 parts PET resin, 35 parts glass fiber (glass fiber ECS11-3.0-534A, monofilament diameter approximately 15 μm), 3 parts lubricant (silicone powder), 0.5 parts antioxidant (phosphite S-9228), 1 part coupling agent (silane coupling agent KH-570, industrial grade raw material). The difference from Example 1 is that the phosphorylated chitosan derivative is not added to the formula.

[0052] Comparative Example 2

[0053] A PET material provided in this embodiment is prepared according to the preparation method of Example 1, and the formula includes the following components in parts by weight:

[0054] 60 parts of PET resin, 10 parts of chitosan, 35 parts of glass fiber (glass fiber ECS11-3.0-534A, monofilament diameter is about 15 μm), 3 parts of lubricant (silicone powder), 0.5 parts of antioxidant (phosphite S-9228), 1 part of coupling agent (silane coupling agent KH-570, industrial grade raw material).

[0055] The PET materials obtained in Examples 1, 2, 3 and Comparative Examples 1 and 2 were subjected to performance tests, including flame retardancy test, glow wire test and ball pressure test.

[0056] To ensure the validity and widespread recognition of the test results, as well as the reproducibility of the test experiments, the flame retardancy test was conducted in accordance with the UL-94 standard, with a sample thickness of 1.6 mm. The glow-wire test was conducted in accordance with the GB / T 5169.11-2017 standard, with a sample thickness of 2.0 mm. The ball pressure test was conducted in accordance with Method A of the GB / T 516.21-2017 standard, with a sample thickness of 4.0 mm, and the test conditions were 125°C.

[0057] The test results are shown in the following table:

[0058]

[0059] From the data in the table we can see that:

[0060] 1. The PET material obtained by adding phosphorylated chitosan derivatives has certain flame retardant properties compared with the PET material obtained without adding phosphorylated chitosan derivatives. The flame retardant property of biomass low-carbon flame retardant PET material can reach V-0, showing good flame retardant properties.

[0061] 2. The PET materials obtained by adding phosphorylated chitosan derivatives all passed the 750°C glow-wire test, while the PET materials obtained without adding phosphorylated chitosan derivatives could not pass the 750°C glow-wire test.

[0062] 3. The ball pressure size at 125°C in the embodiment is 1.2-1.4 mm, while the ball pressure size at 125°C in the comparative example is 1.8-2.2. It is obvious that the PET material obtained by adding the phosphorylated chitosan derivative exhibits more excellent heat resistance and high strength properties.

[0063] In summary, the biomass low-carbon flame-retardant PET material prepared by the present invention uses natural biomass material chitosan to develop a high-efficiency, environmentally friendly and green flame retardant, which effectively solves the problems of non-renewability, harm to human health and easy to cause excessive carbon emissions of traditional flame retardants. At the same time, compared with traditional flame retardants, biomass low-carbon flame-retardant PET not only improves the flame retardant properties of traditional PET materials but also has the characteristics of environmental protection, low carbon and low toxicity. It well solves the frequent fire hazards and the hazards of accompanying toxic substances in the application process of PET materials, protects personal and property safety, and also avoids excessive consumption of renewable resources while maintaining the ecological environment, saves energy and reduces emissions, complies with the national low-carbon and environmental protection policy, improves human health and life, greatly meets the use needs of consumers, and has important value in practical applications.

[0064] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A biomass low-carbon flame-retardant PET material, characterized in that: The composition comprises the following components in parts by weight: 15-70 parts of PET resin; 10-20 parts of phosphorylated chitosan derivative; 30-40 parts of glass fiber; 1 to 5 parts of lubricant; 0.5-1 part of antioxidant; 0.3-1 part of coupling agent; Preparation of the phosphorylated chitosan derivative The following steps are involved: S1, dissolving chitosan in methanesulfonic acid at a weight ratio of chitosan to methanesulfonic acid of 1:13 until no bubbles are present; S2, adding phosphorus pentoxide at a weight ratio of 2:5 to chitosan at 20°C, and stirring under nitrogen for 3 h; S3, after the reaction is completed, anhydrous ether is added to precipitate, and then the solid precipitate is filtered to obtain a solid precipitate, and the solid precipitate is then washed with acetone, anhydrous methanol, and anhydrous ether in sequence; S4, after washing, vacuum drying at room temperature for 10 h to obtain the phosphorylated chitosan derivative; Wherein, the deacetylation degree of the chitosan is ≥95%.

2. The biomass low-carbon flame-retardant PET material according to claim 1, characterized in that: The lubricant is one of silicone powder and montan wax or a combination of the two.

3. The biomass low-carbon flame-retardant PET material according to claim 1, characterized in that: The antioxidant is one or a combination of two of a phenolic primary antioxidant and a phosphite antioxidant.

4. The biomass low-carbon flame-retardant PET material according to claim 1, characterized in that: The coupling agent is a silane coupling agent.

5. The method for preparing a biomass low-carbon flame-retardant PET material according to claim 1, characterized in that: The following steps are involved: The PET resin and the phosphorylated chitosan derivative were dried separately; uniformly mixing PET resin, phosphorylated chitosan derivative, glass fiber, lubricant, antioxidant, and coupling agent to obtain a mixture; The mixture is kneaded, extruded and pelletized to obtain biomass low-carbon flame-retardant PET.

6. The method for preparing a biomass low-carbon flame-retardant PET material according to claim 5, characterized in that: The PET resin and the phosphorylated chitosan derivative are dried separately. The PET resin is placed in an electric blast drying oven at 100° C. and dried for 24 hours. The phosphorylated chitosan derivative is placed in a vacuum drying oven at 40° C. and dried for 10 hours.

7. The method for preparing a biomass low-carbon flame-retardant PET material according to claim 5, characterized in that: The PET resin, phosphorylated chitosan derivative, glass fiber, lubricant, antioxidant and coupling agent are uniformly mixed for 10-30 minutes.

8. The method for preparing a biomass low-carbon flame-retardant PET material according to claim 5, characterized in that: The temperature range of the extrusion of the mixture during the mixing, extrusion and granulation is 190-220°C.

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