Highly flame-retardant engineering plastic particles for furniture and preparation method thereof

Abstract

The invention relates to the field of engineering plastics, and discloses a highly flame-retardant engineering plastic pellet for furniture and a preparation method thereof. The highly flame-retardant engineering plastic pellet comprises: a thermoplastic resin, modified graphene oxide, modified lignin, a lubricant, and a plasticizer; the modified graphene oxide is further reacted with 3-chloropropyltrimethoxysilane to prepare a modified silane coupling agent after reacting p-phenylenediamine and triethyl phosphate, and then the modified graphene oxide is grafted with graphene oxide to prepare the modified silane coupling agent; the modified lignin is grafted with DOPO and a component one on the surface of formaldehyde lignin to prepare the modified lignin, wherein the formaldehyde lignin is prepared by introducing terephthalaldehyde into a side chain of sulfate lignin through an acetal reaction, and the component one is prepared by reacting 3-amino-1,2,4-triazole and 4-aminobenzaldehyde. The invention provides the engineering plastic pellet with excellent mechanical properties, flame retardant properties and aging resistance by adding the modified graphene oxide and the modified lignin.

Description

Technical Field

[0001] The invention belongs to the technical field of engineering plastics, and in particular relates to a highly flame-retardant engineering plastic particle for furniture and a preparation method thereof. Background Art

[0002] Engineering plastics have excellent comprehensive properties, such as high rigidity, low creep, high mechanical strength, good heat resistance, good electrical insulation, and can be used for a long time in harsh chemical and physical environments. They can replace metals as engineering structural materials. Among them, plastic furniture has occupied a very important position in people's daily lives, especially outdoor furniture, such as outdoor leisure tables and chairs, beach chairs, etc.

[0003] The flame retardant properties of existing engineering plastics cannot meet the requirements of modern applications, so they need to be flame-retardant modified. The smoke toxicity, environmental toxicity and bioaccumulation of halogen flame retardants limit their application. The traditional halogen-free flame retardant system has low flame retardant efficiency, large addition amount and poor compatibility with engineering plastics. As a result, the introduction of flame retardants will have a negative impact on the mechanical properties of engineering plastics. There is also the problem of flame retardant migration and exudation. In addition, existing engineering plastics have the disadvantage of easy aging, which seriously affects the use of products. Summary of the invention

[0004] In order to solve the deficiencies mentioned in the above background technology, the purpose of the present invention is to provide a highly flame retardant engineering plastic particle for furniture and a preparation method thereof, and by adding modified graphene oxide and modified lignin, the engineering plastic particle is endowed with excellent mechanical properties, flame retardant properties and aging resistance.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A highly flame-retardant engineering plastic pellet for furniture, comprising the following components in parts by weight: 50-70 parts of thermoplastic resin, 5-10 parts of modified graphene oxide, 2-5 parts of modified lignin, 1-3 parts of lubricant, and 0.2-0.5 parts of plasticizer;

[0007] The modified graphene oxide is prepared by grafting a modified silane coupling agent with graphene oxide, wherein the modified silane coupling agent is prepared by reacting p-phenylenediamine with triethyl phosphate and then reacting with 3-chloropropyltrimethoxysilane to undergo a nucleophilic substitution reaction;

[0008] The modified lignin is prepared by grafting DOPO and component one on the surface of formaldehyde-modified lignin, wherein the formaldehyde-modified lignin is prepared by introducing terephthalaldehyde into the side chain of sulfate lignin by acetal reaction, and component one is prepared by Schiff base reaction of 3-amino-1,2,4-triazole and 4-aminobenzaldehyde.

[0009] Preferably, the thermoplastic resin is one or more combinations of polypropylene, polyethylene, polyvinyl chloride, polycarbonate, polystyrene, and polyamide; the lubricant is one of polyethylene wax or oxidized polyethylene wax; and the plasticizer is one or more combinations of dimethyl phthalate, diisodecyl phthalate, dioctyl phthalate, and dioctyl adipate.

[0010] Preferably, the method for preparing the modified graphene oxide comprises the following steps:

[0011] A. Place p-phenylenediamine, triethyl phosphate and anhydrous ethanol in a reactor, place under reflux at 100-125° C. for 6-8 hours, and after the reaction is completed, remove the solvent using a rotary evaporator to prepare a modified additive;

[0012] B. Dissolve the modified additive in N,N-dimethylformamide, add 3-chloropropyltrimethoxysilane and triethylamine, and stir the mixture at 75-85° C. in a nitrogen atmosphere for 6-8 hours. After the reaction is completed, remove triethylamine hydrochloride by vacuum filtration, and remove the solvent by a rotary evaporator to prepare a modified silane coupling agent;

[0013] C. Ultrasonic dispersion of graphene oxide in anhydrous ethanol, addition of modified silane coupling agent, introduction of nitrogen protection, stirring reaction at 100-125°C for 6-12h, and after the reaction is completed, filtration, washing and drying are performed to prepare modified graphene oxide.

[0014] Preferably, the molar ratio of p-phenylenediamine to triethyl phosphate in step A is 3-5:1.

[0015] Preferably, in step B, the molar ratio of the modifying additive to 3-chloropropyltrimethoxysilane is 1:3-4.

[0016] Preferably, in step C, the mass ratio of graphene oxide to modified silane coupling agent is 1:0.5-2.5.

[0017] Preferably, the preparation method of the modified lignin comprises the following steps:

[0018] (1) Put kraft lignin and terephthalaldehyde in a reactor, add 1,4-dioxane solvent and stir to dissolve, then add concentrated hydrochloric acid, heat to 75-90°C and stir to react for 2-4 hours, cool to room temperature after the reaction is completed, add deionized water to the reaction product to precipitate, then filter, wash and dry to prepare aldehyde lignin;

[0019] (2) 3-amino-1,2,4-triazole, anhydrous ethanol and 4-aminobenzaldehyde are placed in a reactor, stirred and reacted at 80-95° C. for 7-9 hours, and after the reaction is completed, the mixture is filtered, washed and dried to prepare component 1;

[0020] (3) Place the formaldehyde-modified lignin, DOPO and component 1 in a reactor, add anhydrous ethanol solvent, and react at 75-90°C for 2-5 hours. After the reaction is completed, add hydrochloric acid solution to adjust the pH value of the system to 2-3 until precipitation occurs. Then, filter, wash and dry to obtain modified lignin.

[0021] Preferably, in step (2), the molar ratio of 4-aminobenzaldehyde to 3-amino-1,2,4-triazole is 1:1-1.2.

[0022] Preferably, in step (3), the mass ratio of formaldehyded lignin, DOPO and component one is 1-1.7:2.3-3:1.

[0023] The method for preparing highly flame-retardant engineering plastic particles for furniture as described above comprises the following steps: uniformly mixing parts by weight of thermoplastic resin, modified graphene oxide, modified lignin, lubricant and plasticizer to obtain a mixture, and extruding and granulating the mixture using a twin-screw extruder to prepare highly flame-retardant engineering plastic particles for furniture.

[0024] Beneficial effects of the present invention:

[0025] The invention utilizes the amino group at one end of p-phenylenediamine to react with the phosphate group in the structure of triethyl phosphate to prepare a modified additive containing phosphorus and three anti-aging -NH groups, then the amino group in the modified additive structure reacts with the chlorine atom in 3-chloropropyltrimethoxysilane to produce a nucleophilic substitution reaction to prepare a modified silane coupling agent, and further grafts the modified silane coupling agent with graphene oxide to prepare the modified graphene oxide, thereby introducing phosphorus, silicon and a plurality of anti-aging -NH groups into the graphene oxide structure, giving the matrix resin material good flame retardant performance and aging resistance, and the modified silane coupling agent and the graphene oxide are combined through a firm chemical bond to avoid the problem of migration and seepage of the flame retardant component and the anti-aging component, thereby ensuring that the matrix resin material achieves long-term flame retardant and aging resistance effects, and the grafting reaction increases the interlayer spacing of the graphene oxide, which is beneficial to improving the dispersion uniformity of the graphene oxide, and the compatibility with the matrix resin material is improved, so that the mechanical properties of the graphene oxide are fully exerted.

[0026] The invention uses kraft lignin as a raw material, introduces terephthalaldehyde into the lignin side chain through acetal reaction, prepares aldehyde lignin, and simultaneously uses the amino group in the 3-amino-1,2,4-triazole structure to react with the aldehyde group in the 4-aminobenzaldehyde structure to generate an N=CH group to prepare component one, then uses a chemical reaction to react the aldehyde lignin with the amino group in the component one structure to generate another N=CH group, and then further allows the -PH bond in the DOPO structure to react with the N=CH group to prepare modified lignin, thereby introducing nitrogen and phosphorus flame retardant components into the lignin structure through strong chemical bond bonding, giving the matrix resin material excellent flame retardant performance, and improving the dispersibility of lignin in the matrix resin material, thereby improving the reinforcement effect. DETAILED DESCRIPTION

[0027] The following will be combined with 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.

[0028] Example 1 A method for preparing modified graphene oxide comprises the following steps:

[0029] A. 27 g of p-phenylenediamine, 9.1 g of triethyl phosphate and 100 mL of anhydrous ethanol were placed in a reactor, and refluxed at 120° C. for 8 h. After the reaction was completed, the solvent was removed using a rotary evaporator to prepare a modified additive;

[0030] The relative molecular weight of the modified additive prepared in step A is 368.57, and its synthesis steps are as follows:

[0031] ;

[0032] B. Take 9.2g of the modified additive and dissolve it in 100mL of N,N-dimethylformamide, add 17.4g of 3-chloropropyltrimethoxysilane and 10mL of triethylamine, place it at 80°C in a nitrogen atmosphere and stir to react for 7h. After the reaction is completed, remove triethylamine hydrochloride by vacuum filtration, and remove the solvent by rotary evaporator to prepare a modified silane coupling agent;

[0033] C. Take 1g of graphene oxide and ultrasonically disperse it in anhydrous ethanol, add 1.4g of modified silane coupling agent, pass nitrogen protection, place it at 120°C and stir to react for 10h. After the reaction is completed, filter, wash and dry to prepare modified graphene oxide.

[0034] Example 2 A method for preparing modified lignin comprises the following steps:

[0035] (1) 5 g of kraft lignin and 6.7 g of terephthalaldehyde were placed in a reactor, 25 mL of 1,4-dioxane solvent was added and stirred to dissolve, then 0.8 mL of concentrated hydrochloric acid was added, the temperature was raised to 80 ° C, and the mixture was stirred to react for 3 h. After the reaction was completed, the mixture was cooled to room temperature, deionized water was added to the reaction product to precipitate, and then the mixture was filtered, washed, and dried to prepare aldehyde lignin;

[0036] (2) 1.7 g of 3-amino-1,2,4-triazole, 100 mL of anhydrous ethanol and 2.4 g of 4-aminobenzaldehyde were placed in a reactor and stirred at 85° C. for 8 h. After the reaction was completed, the mixture was filtered, washed and dried to prepare component 1.

[0037] (3) 5 g of formaldehyde-modified lignin, 8.9 g of DOPO and 3.1 g of component 1 were placed in a reactor, 300 mL of anhydrous ethanol solvent was added, and the mixture was reacted at 85 °C for 4 h. After the reaction was completed, a hydrochloric acid solution was added to adjust the pH value of the system to 3 until a precipitate was precipitated. The precipitate was then filtered, washed and dried to obtain modified lignin.

[0038] Example 3 A highly flame-retardant engineering plastic pellet for furniture, comprising the following components in parts by weight:

[0039] 52 parts of thermoplastic resin polypropylene, 5 parts of modified graphene oxide prepared in Example 1, 2 parts of modified lignin prepared in Example 2, 1.5 parts of lubricant polyethylene wax, and 0.2 parts of plasticizer dimethyl phthalate.

[0040] The preparation method of the above-mentioned highly flame-retardant engineering plastic particles for furniture comprises the following steps: uniformly mixing parts by weight of thermoplastic resin, modified graphene oxide, modified lignin, lubricant and plasticizer to obtain a mixture, and extruding and granulating the mixture using a twin-screw extruder to prepare highly flame-retardant engineering plastic particles for furniture.

[0041] Example 4 A highly flame-retardant engineering plastic pellet for furniture comprises the following components in parts by weight:

[0042] 60 parts of thermoplastic resin polypropylene, 8 parts of modified graphene oxide prepared in Example 1, 3 parts of modified lignin prepared in Example 2, 2 parts of lubricant polyethylene wax, and 0.4 parts of plasticizer diisodecyl phthalate.

[0043] The preparation method of the above-mentioned highly flame-retardant engineering plastic particles for furniture is the same as that in Example 3.

[0044] Example 5 A highly flame-retardant engineering plastic pellet for furniture, comprising the following components in parts by weight:

[0045] 68 parts of thermoplastic resin polypropylene, 10 parts of modified graphene oxide prepared in Example 1, 4 parts of modified lignin prepared in Example 2, 2.5 parts of lubricant polyethylene wax, and 0.5 parts of plasticizer dioctyl phthalate.

[0046] The preparation method of the above-mentioned highly flame-retardant engineering plastic particles for furniture is the same as that in Example 3.

[0047] Comparative Example 1 A highly flame-retardant engineering plastic pellet for furniture comprises the following components in parts by weight:

[0048] 68 parts of thermoplastic resin polypropylene, 10 parts of graphene oxide, 4 parts of modified lignin prepared in Example 2, 2.5 parts of lubricant polyethylene wax, and 0.5 parts of plasticizer dioctyl phthalate.

[0049] The preparation method of the above-mentioned highly flame-retardant engineering plastic particles for furniture is the same as that in Example 3.

[0050] Comparative Example 2 A highly flame-retardant engineering plastic pellet for furniture comprises the following components in parts by weight:

[0051] 68 parts of thermoplastic resin polypropylene, 10 parts of modified graphene oxide prepared in Example 1, 4 parts of lignin, 2.5 parts of lubricant polyethylene wax, and 0.5 parts of plasticizer dioctyl phthalate.

[0052] The preparation method of the above-mentioned highly flame-retardant engineering plastic particles for furniture is the same as that in Example 3.

[0053] Performance Testing

[0054] The high flame retardant engineering plastic particles for furniture prepared in Examples 3-5 and Comparative Examples 1-2 were subjected to performance testing: they were injection molded into standard dumbbell-shaped specimens with a thickness of 4 mm, and a tensile performance test was performed using a universal mechanical testing machine in accordance with GB / T 1040.2-2022 standard, and the tensile speed was set to 50 mm / min; they were injection molded into specimens with a thickness of 4 mm, a width of 10 mm, and a length of 80 mm, and an impact strength test was performed in accordance with GB / T1843-2008 standard; and after aging at 100°C for 24 h and 48 h, the change rates of the tensile strength and impact strength were tested to evaluate the material's resistance to heat and oxygen aging; the flame retardant properties were tested using a limiting oxygen index test and a vertical burning test, and the data results are shown in Table 1.

[0055] Table 1 Test results of sample performance

[0056]

[0057] From the data in Table 1, it can be seen that the engineering plastic particles prepared in Examples 3-5 of the present invention have high tensile strength and good impact resistance. After aging at 100°C for 24h and 48h, they still have high tensile strength and impact strength, excellent aging resistance, and excellent flame retardant effect. In Comparative Example 1, graphene oxide was not modified, and its measured tensile strength, impact strength and flame retardant performance were lower than those of Examples 3-5, and the tensile strength change rate and impact strength change rate were significantly lower than those of Examples 3-5, indicating that the grafting of modified silane coupling agents can improve the mechanical properties, flame retardant properties and aging resistance of the material. In Comparative Example 2, lignin was not modified, and its measured tensile strength, impact strength and flame retardant performance were lower than those of Examples 3-5. The reason is that nitrogen and phosphorus flame retardant components were not introduced into the lignin structure, and its mechanical properties decreased due to the occurrence of agglomeration.

[0058] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0059] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements all fall within the scope of the present invention to be protected.

Claims

1. A highly flame retardant engineering plastic pellet for furniture, characterized in that: The invention comprises the following components in parts by weight: 50-70 parts of thermoplastic resin, 5-10 parts of modified graphene oxide, 2-5 parts of modified lignin, 1-3 parts of lubricant, and 0.2-0.5 parts of plasticizer; The modified graphene oxide is prepared by grafting a modified silane coupling agent with graphene oxide, wherein the modified silane coupling agent is prepared by reacting p-phenylenediamine with triethyl phosphate and then reacting with 3-chloropropyltrimethoxysilane to undergo a nucleophilic substitution reaction; The molar ratio of p-phenylenediamine to triethyl phosphate is 3-5:1; The modified lignin is prepared by grafting DOPO and component one on the surface of formaldehyde-modified lignin, wherein the formaldehyde-modified lignin is prepared by introducing terephthalaldehyde into the side chain of sulfate lignin by acetal reaction, and component one is prepared by Schiff base reaction of 3-amino-1,2,4-triazole and 4-aminobenzaldehyde.

2. The highly flame retardant engineering plastic particles for furniture according to claim 1, characterized in that: The thermoplastic resin is one or more combinations of polypropylene, polyethylene, polyvinyl chloride, polycarbonate, polystyrene, and polyamide; the lubricant is one of polyethylene wax or oxidized polyethylene wax; the plasticizer is one or more combinations of dimethyl phthalate, diisodecyl phthalate, dioctyl phthalate, and dioctyl adipate.

3. The highly flame retardant engineering plastic particles for furniture according to claim 1, characterized in that: The preparation method of the modified graphene oxide comprises the following steps: A. Place p-phenylenediamine, triethyl phosphate and anhydrous ethanol in a reactor, place under reflux at 100-125° C. for 6-8 hours, and after the reaction is completed, remove the solvent using a rotary evaporator to prepare a modified additive; B. Dissolve the modified additive in N,N-dimethylformamide, add 3-chloropropyltrimethoxysilane and triethylamine, and stir the mixture at 75-85° C. in a nitrogen atmosphere for 6-8 hours. After the reaction is completed, remove triethylamine hydrochloride by vacuum filtration, and remove the solvent by a rotary evaporator to prepare a modified silane coupling agent; C. Ultrasonic dispersion of graphene oxide in anhydrous ethanol, addition of modified silane coupling agent, introduction of nitrogen protection, stirring reaction at 100-125°C for 6-12h, and after the reaction is completed, filtration, washing and drying are performed to prepare modified graphene oxide.

4. The highly flame retardant engineering plastic particles for furniture according to claim 3, characterized in that: In the step B, the molar ratio of the modifying additive to 3-chloropropyltrimethoxysilane is 1:3-4.

5. The highly flame retardant engineering plastic particles for furniture according to claim 3, characterized in that: In the step C, the mass ratio of graphene oxide to modified silane coupling agent is 1:0.5-2.

5.

6. The highly flame retardant engineering plastic particles for furniture according to claim 1, characterized in that: The preparation method of the modified lignin comprises the following steps: (1) Put kraft lignin and terephthalaldehyde in a reactor, add 1,4-dioxane solvent and stir to dissolve, then add concentrated hydrochloric acid, heat to 75-90°C and stir to react for 2-4 hours, cool to room temperature after the reaction is completed, add deionized water to the reaction product to precipitate, then filter, wash and dry to prepare aldehyde lignin; (2) 3-amino-1,2,4-triazole, anhydrous ethanol and 4-aminobenzaldehyde are placed in a reactor, stirred and reacted at 80-95° C. for 7-9 hours, and after the reaction is completed, the mixture is filtered, washed and dried to prepare component 1; (3) Place the formaldehyde-modified lignin, DOPO and component 1 in a reactor, add anhydrous ethanol solvent, and react at 75-90°C for 2-5 hours. After the reaction is completed, add hydrochloric acid solution to adjust the pH value of the system to 2-3 until precipitation occurs. Then, filter, wash and dry to obtain modified lignin.

7. The highly flame-retardant engineering plastic particles for furniture according to claim 6, characterized in that: In the step (2), the molar ratio of 4-aminobenzaldehyde to 3-amino-1,2,4-triazole is 1:1-1.

2.

8. The highly flame-retardant engineering plastic particles for furniture according to claim 6, characterized in that: In the step (3), the mass ratio of the formaldehyded lignin, DOPO and component one is 1-1.7:2.3-3:

1.

9. The method for preparing highly flame-retardant engineering plastic particles for furniture according to any one of claims 1 to 8, characterized in that: The following steps are involved: 50-70 parts of thermoplastic resin, 5-10 parts of modified graphene oxide, 2-5 parts of modified lignin, 1-3 parts of lubricant and 0.2-0.5 parts of plasticizer are uniformly mixed to obtain a mixture, and the mixture is extruded and granulated by a twin-screw extruder to prepare high flame retardant engineering plastic particles for furniture.

Images