A bio-based toughened and flame-retardant PLA / ABS composite material and its preparation method

Abstract

The present invention relates to a bio-based toughened and flame-retardant PLA / ABS composite material and a preparation method thereof, belonging to the technical field of PLA composite material preparation. The material comprises the following raw materials in parts by weight: 75-90 parts of PLA resin, 10-25 parts of ABS resin, 10-20 parts of an auxiliary agent, and 0.5-1.5 parts of a nucleating agent; the auxiliary agent is prepared by ring-opening polymerization of modified polydimethylsiloxane and caprolactone under the action of a ring-opening catalyst; the modified polydimethylsiloxane is prepared by reacting bis(aminopropyl)polydimethylsiloxane with a reactive weather-resistant compound. By introducing the auxiliary agent, the present invention utilizes the flexible chain ends of siloxane and the chain ends of polycaprolactone in the molecular structure of the auxiliary agent to play the roles of a compatibilizer and heat-resistant flame retardant, and synergistically improves the toughness of the obtained composite material with the ABS resin and the nucleating agent.

Description

Technical Field

[0001] The present invention belongs to the technical field of the preparation of PLA composites, and specifically relates to a bio-based toughened and flame-retardant PLA / ABS composite material and a preparation method thereof. Background Art

[0002] PLA resin refers to polylactic acid resin, also known as poly(lactic acid), which is a polyester polymer obtained by polymerizing lactic acid as the main raw material. It has good biodegradability, mechanical properties, and transparent appearance. However, PLA also has some disadvantages, such as insufficient flexibility, low impact strength, low heat distortion temperature, and poor heat resistance. These disadvantages limit the application fields of PLA. ABS resin refers to acrylonitrile-butadiene-styrene copolymer, where ABS is the abbreviation of Acrylonitrile Butadiene Styrene. It has good impact strength, dimensional stability, dyeability, mechanical strength, stiffness, and corrosion resistance, as well as low water absorption. It also has very good transparency and polishing effect, and is the preferred material to replace PC sheets. Therefore, introducing ABS into PLA resin to form an alloy resin can effectively improve the disadvantages of PLA resin such as insufficient flexibility, low impact strength, low heat distortion temperature, and poor heat resistance. However, the compatibility between PLA and ABS is poor, and simply relying on the filling of ABS cannot completely obtain a flame-retardant PLA composite material.

[0003] Based on this, the present invention provides a bio-based toughened and flame-retardant PLA / ABS composite material and a preparation method thereof. Summary of the Invention

[0004] In view of the problems provided in the technical background, the present invention provides a bio-based toughened and flame-retardant PLA / ABS composite material and a preparation method thereof.

[0005] One object of the present invention can be achieved by the following technical solutions:

[0006] A bio-based toughened and flame-retardant PLA / ABS composite material, comprising the following raw materials in parts by weight: 75-90 parts of PLA resin, 10-25 parts of ABS resin, 10-20 parts of an auxiliary agent, and 0.5-1.5 parts of a nucleating agent;

[0007] The auxiliary agent is prepared by ring-opening polymerization reaction of modified polydimethylsiloxane and caprolactone under the action of a ring-opening catalyst;

[0008] The modified polydimethylsiloxane is prepared by reacting bis(aminopropyl)polydimethylsiloxane with a reactive weather-resistant compound.

[0009] Further, the reaction conditions of the ring-opening polymerization reaction are: reacting at a reaction temperature of 90-130°C for 12-48 h under a nitrogen atmosphere.

[0010] Furthermore, the mass ratio of the modified polydimethylsiloxane to caprolactone is 15-25:5-8.

[0011] Furthermore, the ring-opening catalyst is one of stannous isooctanoate, dibutyltin dilaurate, trifluoromethanesulfonic acid, and hydrofluoric acid.

[0012] Preferably, the reaction for obtaining the auxiliary agent comprises the following steps:

[0013] After the modified polydimethylsiloxane and caprolactone are mixed, a ring-opening catalyst is added under nitrogen atmosphere at 90-130°C with stirring, and the reaction is continued with heat preservation and stirring for 12-48 hours. The reaction is stopped, and the obtained product is repeatedly treated with a dichloromethane and isopropanol system (dispersion, precipitation, washing, centrifugation), and finally dried to obtain an additive.

[0014] Furthermore, the reaction conditions for obtaining the modified polydimethylsiloxane are: reaction temperature of 0-20° C., and reaction time of 3-8 h.

[0015] Furthermore, the mass ratio of the bisaminopropyl polydimethylsiloxane to the reactive weather-resistant compound is 15-25:3.

[0016] Furthermore, the number average molecular weight of the bisaminopropyl polydimethylsiloxane is 1000-2000;

[0017] Preferably, the number average molecular weight of the bisaminopropyl polydimethylsiloxane is 1000-1500 or 1500-2000.

[0018] Preferably, the reaction for obtaining the modified polydimethylsiloxane comprises the following steps:

[0019] Mix bisaminopropyl polydimethylsiloxane, reactive weather-resistant compound, triethylamine and dichloromethane at 0-5°C, slowly heat to room temperature (20±5°C), stir and react for 3-8h, stop the reaction, rotary evaporate, wash with water, centrifuge and dry to obtain modified polydimethylsiloxane.

[0020] Furthermore, the reactive weather-resistant compound is prepared by reacting chloroacetyl chloride and 2,4-dihydroxybenzophenone in the presence of an organic solvent and an acid-binding agent at 0-25°C.

[0021] Furthermore, the molar ratio of chloroacetyl chloride to 2,4-dihydroxybenzophenone is 1.1-1.3:1.

[0022] Furthermore, the organic solvent is one of dichloromethane, polytetrahydrofuran, N,N-dimethylformamide, and xylene.

[0023] Preferably, the acidifying agent is triethylamine.

[0024] Furthermore, the nucleating agent is a mixture of an organic nucleating agent and an inorganic nucleating agent in a mass ratio of 2-3:1.

[0025] Furthermore, the organic nucleating agent is one of TMC-328 and TMC-300 or a mixture of the two in any ratio;

[0026] Preferably, the organic nucleating agent is TMC-300.

[0027] Furthermore, the inorganic nucleating agent is one of carbon nanotubes, zinc oxide whiskers, and calcium carbonate whiskers;

[0028] Preferably, the inorganic nucleating agent is carbon nanotubes.

[0029] Another object of the present invention can be achieved by the following technical solutions:

[0030] A method for preparing a bio-based toughened flame-retardant PLA / ABS composite material, comprising:

[0031] PLA resin, ABS resin, additives and nucleating agents are mixed, melt-blended and extruded, and granulated to obtain a composite material.

[0032] Furthermore, the temperature during the melt blending extrusion is 200-240° C., and the rotation speed is 200-400 r / min.

[0033] Beneficial effects of the present invention:

[0034] The present invention discloses a bio-based toughened flame-retardant PLA / ABS composite material and a preparation method thereof. By introducing an auxiliary agent, the siloxane flexible chain end and the polycaprolactone chain end in the auxiliary agent's molecular structure are utilized, so that the auxiliary agent plays the role of a compatibilizer and has heat resistance and flame retardancy. The polycaprolactone chain end and the PLA resin chain segment are both polyester-type chain segments and have good compatibility with the PLA resin chain segment. The siloxane flexible chain can be combined with the ABS resin molecular chain segment, so that the auxiliary agent acts as a compatibilizer, and the mixing processability of the PLA resin and the ABS resin is good. The siloxane flexible chain acts as a silicon-based flame retardant during combustion, thereby improving the flame retardant performance of the composite material. Furthermore, the auxiliary agent molecular chain also contains a benzophenone light-absorbing structure, thereby solving the problem of low weather resistance of the composite material caused by the introduction of the ABS resin and improving the weather resistance of the obtained composite material. Finally, the nucleating agent promotes the crystallization performance of the PLA resin, and cooperates with the auxiliary agent and the ABS resin to solve the problem of insufficient flexibility of the PLA resin. DETAILED DESCRIPTION

[0035] Next, in combination with the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0036] Example 1

[0037] Preparation of the additive:

[0038] Preparation of the reactive weather-resistant compound: 0.1 mol of 2,4-dihydroxybenzophenone, 0.12 mol of triethylamine and 60 mL of dichloromethane were mixed evenly, and then at 0-3 °C, 0.12 mol of chloroacetyl chloride was added dropwise. After the addition was complete, the temperature was slowly raised to room temperature, and the reaction was continued with stirring for 4 h. The reaction was stopped, cooled, washed with water, separated, and the organic phase was recrystallized with methanol and dried to obtain the reactive weather-resistant compound;

[0039] Preparation of the modified polydimethylsiloxane: 15 g of bis(aminopropyl)polydimethylsiloxane, 3 g of the reactive weather-resistant compound, 1.5 g of triethylamine and 100 mL of dichloromethane were mixed evenly at 0-5 °C, and then slowly heated to room temperature (20±5 °C) and stirred for 3 h. The reaction was stopped, rotary evaporated, washed with water, centrifuged and dried to obtain the modified polydimethylsiloxane; among them, the number-average molecular weight of bis(aminopropyl)polydimethylsiloxane was 1000-1500;

[0040] Obtaining of the additive: 15 g of the modified polydimethylsiloxane and 5 g of ε-caprolactone were mixed, and then 0.4 g of stannous octoate was added under nitrogen atmosphere, at 90 °C with stirring, and the reaction was continued with stirring for 24 h. The reaction was stopped, and the obtained product was repeatedly treated (dispersed, precipitated, washed, centrifuged) with a dichloromethane and isopropanol system, and finally dried to obtain the additive.

[0041] Example 2

[0042] Preparation of the additive:

[0043] Preparation of the reactive weather-resistant compound: 0.1 mol of 2,4-dihydroxybenzophenone, 0.13 mol of triethylamine and 60 mL of dichloromethane were mixed evenly, and then at 0-3 °C, 0.13 mol of chloroacetyl chloride was added dropwise. After the addition was complete, the temperature was slowly raised to room temperature, and the reaction was continued with stirring for 6 h. The reaction was stopped, cooled, washed with water, separated, and the organic phase was recrystallized with methanol and dried to obtain the reactive weather-resistant compound;

[0044] Preparation of modified polydimethylsiloxane: 25 g of bis(aminopropyl)polydimethylsiloxane, 3 g of reactive weather-resistant compound, 1.5 g of triethylamine and 100 mL of dichloromethane were mixed evenly at 0 - 5 °C, slowly heated to room temperature (20 ± 5 °C), stirred and reacted for 8 h, then the reaction was stopped, rotary evaporation was carried out, followed by washing with water, centrifugation, and drying to obtain the modified polydimethylsiloxane; among them, the number-average molecular mass of bis(aminopropyl)polydimethylsiloxane was 1500 - 2000;

[0045] Obtaining of the additive: After mixing 25 g of the modified polydimethylsiloxane and 8 g of ε-caprolactone, 0.63 g of stannous octoate was added under nitrogen atmosphere, at 90 - 130 °C with stirring, and the mixture was kept warm and stirred for reaction for 48 h. Then the reaction was stopped, and the obtained product was repeatedly treated (dispersed, precipitated, washed, centrifuged) with a dichloromethane and isopropanol system, and finally dried to obtain the additive.

[0046] Example 3

[0047] Preparation of PLA / ABS composite material:

[0048] Prepare raw materials including the following parts by weight: 75 parts of PLA resin, 25 parts of ABS resin, 20 parts of the additive prepared in Example 1, and 0.5 part of nucleating agent; among them, the nucleating agent was composed of TMC-300 and carbon nanotubes mixed according to a mass ratio of 2:1;

[0049] Melting and extrusion: After mixing the PLA resin, ABS resin, additive and nucleating agent, they were melt-blended and extruded, and pelletized to obtain the composite material. Among them, the temperature during the melt-blending extrusion was 200 - 240 °C, and the rotation speed was 200 - 400 r / min.

[0050] Example 4

[0051] Preparation of PLA / ABS composite material:

[0052] Prepare raw materials including the following parts by weight: 85 parts of PLA resin, 15 parts of ABS resin, 15 parts of the additive prepared in Example 2, and 1 part of nucleating agent; the nucleating agent was composed of TMC-300 and carbon nanotubes mixed according to a mass ratio of 2.5:1;

[0053] Melting and extrusion: After mixing the PLA resin, ABS resin, additive and nucleating agent, they were melt-blended and extruded, and pelletized to obtain the composite material. Among them, the temperature during the melt-blending extrusion was 200 - 240 °C, and the rotation speed was 200 - 400 r / min.

[0054] Example 5

[0055] Preparation of PLA / ABS composite material:

[0056] The preparation includes the following raw materials in parts by weight: 90 parts of PLA resin, 10 parts of ABS resin, 10 parts of the auxiliary agent prepared in Example 1, and 1.5 parts of nucleating agent; the nucleating agent is composed of TMC-300 and carbon nanotubes mixed in a mass ratio of 3:1.

[0057] Melt extrusion: After mixing PLA resin, ABS resin, auxiliary agent and nucleating agent, melt blending and extruding, and pelletizing to obtain a composite material. Among them, the temperature during the melt blending and extrusion is 200 - 240 °C, and the rotation speed is 200 - 400 r / min.

[0058] Comparative Example 1

[0059] Preparation of PLA / ABS composite material: Compared with Example 5, the equivalent parts of the auxiliary agent in Example 5 are replaced with the modified polydimethylsiloxane prepared in Example 1, and the rest are the same.

[0060] Comparative Example 2

[0061] Preparation of PLA / ABS composite material: Compared with Example 5, the equivalent parts of the auxiliary agent in Example 5 are replaced with polycaprolactone prepared by the following steps, and the rest are the same:

[0062] Add 0.4 g of stannous octoate to 5 g of caprolactone under nitrogen atmosphere, at 90 °C with stirring, continue to keep warm and stir for reaction for 24 h, stop the reaction, and repeatedly treat the obtained product with a dichloromethane and isopropanol system (dispersion, precipitation, washing, centrifugation), and finally dry to obtain polycaprolactone.

[0063] Comparative Example 3

[0064] Preparation of PLA / ABS composite material: Compared with Example 5, the equivalent parts of the auxiliary agent in Example 5 are replaced with maleic anhydride grafted ABS, and the rest are the same.

[0065] Comparative Example 4

[0066] Preparation of PLA / ABS composite material: Compared with Example 5, the nucleating agent in Example 5 is deleted, and the rest are the same.

[0067] Perform physical property tests on the composite materials obtained in Examples 3 - 5 and Comparative Examples 1 - 4, and the obtained results are shown in Table 1.

[0068] Table 1

[0069] Tensile strength Flexural strength Notched impact strength Flame retardant grade Heat deflection temperature GB / T 1040.2 GB / T 9341 GB / T 1043.1 UL-94 ISO 75-2 Unit Mpa Mpa <![CDATA[KJ / m 2 > / ℃ Example 3 76 104 16.8 V-1 117 Example 4 63 94 16.2 V-1 113 Example 5 60 91 15.1 V-1 109 Comparative example 1 41 72 11.3 V-1 104 Comparative example 2 45 70 12.5 V-2 95 Comparative example 3 47 82 13.5 V-2 92 Comparative example 4 57 89 12.7 V-1 101

[0070] From the data in Table 1, it can be seen that the composite materials obtained in Examples 3 - 5 have good mechanical strength, toughness and thermal stability, and have certain flame retardant properties.

[0071] In the description of the specification, the description referring to terms such as "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0072] The above content is only an illustration and explanation of the present invention. Those skilled in the art of this technology can make various modifications or supplements to the described specific embodiments or use similar methods for substitution, as long as they do not deviate from the invention or exceed the scope defined by the claims of the present invention, they should fall within the protection scope of the present invention.

Claims

1. A bio-based toughened and flame-retardant PLA / ABS composite material, characterized in that, It comprises the following raw materials in parts by weight: 75 - 90 parts of PLA resin, 10 - 25 parts of ABS resin, 10 - 20 parts of auxiliary agent, and 0.5 - 1.5 parts of nucleating agent; The auxiliary agent is prepared by ring-opening polymerization of modified polydimethylsiloxane and caprolactone under the action of a ring-opening catalyst; The modified polydimethylsiloxane is prepared by reacting bis(aminopropyl)polydimethylsiloxane with a reactive weather-resistant compound; The reactive weather-resistant compound is prepared by reacting chloroacetyl chloride and 2,4-dihydroxybenzophenone in the presence of an organic solvent and a deacidifying agent; The molar ratio of chloroacetyl chloride to 2,4-dihydroxybenzophenone is 1.1 - 1.3:1; The organic solvent is dichloromethane; The deacidifying agent is triethylamine.

2. The bio-based toughened and flame-retardant PLA / ABS composite material according to claim 1, wherein The reaction conditions of the ring-opening polymerization reaction are: reacting at a reaction temperature of 90 - 130 °C for 12 - 48 h under a nitrogen atmosphere.

3. A bio-based toughened and flame-retardant PLA / ABS composite material according to claim 1, wherein The mass ratio of the modified polydimethylsiloxane to caprolactone is 15 - 25:5 - 8.

4. A bio-based toughened and flame-retardant PLA / ABS composite material according to claim 1, characterized in that, The ring-opening catalyst is one of stannous octoate, dibutyltin dilaurate, and trifluoromethanesulfonic acid.

5. A bio-based toughened and flame-retardant PLA / ABS composite material according to claim 1, wherein, The reaction conditions for obtaining the modified polydimethylsiloxane are: reaction temperature is 0 - 20 °C, and reaction time is 3 - 8 h.

6. A bio-based toughened and flame-retardant PLA / ABS composite according to claim 1, characterized in that, The mass ratio of bis(aminopropyl)polydimethylsiloxane to the reactive weather-resistant compound is 15 - 25:

3.

7. A bio-based toughened and flame-retardant PLA / ABS composite according to claim 1, wherein The number-average molecular weight of the bis(aminopropyl)polydimethylsiloxane is 1000 - 2000.

8. A bio-based toughened and flame-retardant PLA / ABS composite material according to claim 1, characterized in that, The nucleating agent is composed of an organic nucleating agent and an inorganic nucleating agent mixed in a mass ratio of 2 - 3:

1.

9. The preparation method of a bio-based toughened and flame-retardant PLA / ABS composite material according to any one of claims 1-8, characterized in that, It includes: After mixing the PLA resin, ABS resin, auxiliary agent, and nucleating agent, melt-blending and extruding, and pelletizing, a composite material is obtained.