Flame Retardant Composite and Its Preparation Method

Abstract

The present application discloses a flame retardant composite and a preparation method thereof, wherein the flame retardant composite comprises: a matrix, wherein the matrix is a composite of polylactic acid and polybutylene adipate / terephthalate; flame retardant gas gel microspheres; phosphorus-containing epoxy; antioxidant; nucleating agent; coupling agent; in terms of weight, the matrix accounts for 85 to 97 parts, the flame retardant gas gel microspheres account for 1 to 5 parts, the phosphorus-containing epoxy accounts for 0.5 to 2 parts, the antioxidant accounts for 0.01 to 3 parts, the nucleating agent accounts for 0.1 to 2 parts, and the coupling agent accounts for 1 to 3 parts. The flame retardant composite described in the present application has the characteristics of being green and environmentally friendly, highly flame retardant, and having excellent comprehensive performance, and can be applied in fields requiring high flame retardant performance.

Description

Technical Field

[0001] The present application relates to the technical field of polymer materials, and in particular to a flame retardant polylactic acid / (polyadipate / butylene terephthalate) composite and a preparation method thereof. Background Art

[0002] The development of bio-based materials is an inevitable measure to alleviate the oil crisis and ensure sustainable development, and it is also an important direction for the structural adjustment of the polymer materials industry. At present, many bio-based materials and degradable materials have been developed. With the implementation of the plastic ban, more and more fields are beginning to use bio-based materials to replace petroleum-based materials.

[0003] Polylactic acid (PLA) is a typical representative of the current commercial bio-based degradable materials. It is made of starch raw materials from renewable plant resources (corn, cassava, etc.), has excellent biodegradability, and generates carbon dioxide and water after degradation, which does not pollute the environment. PLA has been used in biomedicine, food packaging and other fields. However, PLA itself is not tough enough, so it is often used in combination with the degradable copolymer poly (butylene adipate / terephthalate) (PBAT) in actual use. With the development of PLA / PBAT composite modification and processing technology, its comprehensive performance has been further improved. In addition to traditional application fields, it has been increasingly used in the fields of electronics, automobiles, and building materials. The above applications have put forward higher requirements on the flame retardant properties of PLA / PBAT composites. However, PLA / PBAT composites are extremely flammable in air and are accompanied by severe droplet phenomenon, which limits their application in many fields. Therefore, the development of flame-retardant PLA / PBAT composites has received widespread attention. Summary of the invention

[0004] The technical problem to be solved by the technical solution of this application is to provide a flame retardant composite with PLA / PBAT as the matrix, which has the advantages of being green and environmentally friendly and having high flame retardant efficiency, while being able to minimize the impact of additives on the performance of the PLA / PBAT body.

[0005] One aspect of the present application provides a flame retardant composite, comprising: a matrix, wherein the matrix is a composite of polylactic acid and polybutylene adipate / terephthalate; flame retardant gas gel microspheres; phosphorus-containing epoxy; antioxidant; nucleating agent and coupling agent; in terms of weight parts, the matrix accounts for 85 to 97 parts, the flame retardant gas gel microspheres account for 1 to 5 parts, the phosphorus-containing epoxy accounts for 0.5 to 2 parts, the antioxidant accounts for 0.01 to 3 parts, the nucleating agent accounts for 0.1 to 2 parts, and the coupling agent accounts for 1 to 3 parts.

[0006] In some embodiments of the present application, the flame-retardant gas aerogel microspheres are silica aerogel microspheres containing phosphorus-based flame-retardant groups.

[0007] In some embodiments of the present application, the structural formula of the silica aerogel microspheres containing phosphorus-based flame retardant groups is:

[0008]

[0009] Among them, the R group includes:

[0010]

[0011] Or Any one or several of them.

[0012] In some embodiments of the present application, the phosphorus-containing epoxy includes:

[0013]

[0014] Or Any one or several of them.

[0015] In some embodiments of the present application, the antioxidant includes any one or more of pentaerythritol tetrakis(β-(3,5-di-tert-butyl-4-hydroxyphenyl))propionate, octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, diethyl (3,5-di-tert-butyl-4-hydroxybenzyl)phosphonate, and tris(2,4-di-tert-butylphenyl)phosphite.

[0016] In some embodiments of the present application, the nucleating agent is at least one of ethylene bisstearamide, ethylene hydroxy bisstearamide, 1,3,5-tribenzamide derivative, lanthanum phenylphosphate, cerium phenylphosphate, montmorillonite, talc powder, diphenyl sebacate dinitrile, or diphenyl adipate dinitrile.

[0017] In some embodiments of the present application, the coupling agent is at least one or more of 3-aminopropyltrihydroxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, N-β(aminoethyl)-γ-aminopropyltrimethoxysilane, and N-β(aminoethyl)-γ-aminopropyltriethoxysilane; the weight ratio of polylactic acid to polybutylene adipate / terephthalate in the matrix is 80:20 - 20:80.

[0018] On the other hand, the present application provides a method for preparing a flame retardant composite, including: melt-blending the above-mentioned matrix, flame retardant aerogel microspheres, phosphorus-containing epoxy, antioxidant, nucleating agent, and coupling agent.

[0019] In some embodiments of the present application, the flame-retardant aerogel microspheres are silica aerogel microspheres containing phosphorus-based flame-retardant groups. The method for forming the silica aerogel microspheres containing phosphorus-based flame-retardant groups includes: using a phosphorus-containing siloxane precursor and preparing it by the sol-gel method. Among them, the phosphorus-containing siloxane precursor includes

[0020]

[0021] and any one or more of them.

[0022] In some embodiments of the present application, the sol-gel method includes: dissolving the phosphorus-containing siloxane precursor in ethanol, adding deionized water for the first stirring, adjusting the pH of the system to 2-3, and continuously stirring until hydrolysis to obtain a sol; pouring the sol into a pre-prepared mixed system of oil phase and emulsifier, performing the second stirring, adjusting the pH of the system to 7-8, and then continuously stirring until wet gel microspheres are obtained; washing, filtering, and aging the wet gel microspheres, and then forming the flame-retardant aerogel microspheres through solvent exchange and atmospheric drying; or washing, filtering, aging, and freeze-drying the wet gel microspheres to form the flame-retardant aerogel microspheres.

[0023] Compared with the prior art, the technical solution of the present application has the following beneficial effects:

[0024] The flame-retardant composite of the present application uses a PLA / PBAT composite as the matrix, adds flame-retardant aerogel microspheres (FRA) and phosphorus-containing epoxy as flame retardants. Through the flame-retardant and heat-insulating effects of FRA and the charring and coupling effects of the phosphorus-containing epoxy flame retardant, the flame-retardant performance of the PLA / PBAT composite is synergistically improved. On the one hand, under the condition of maintaining a high flame-retardant level, the addition amount of the flame retardant is greatly reduced; on the other hand, due to the greatly reduced addition amount of the flame retardant and the coupling effect of the phosphorus-containing epoxy and the coupling agent, the interfacial interaction can be improved, and the influence on the mechanical properties of the PLA / PBAT composite can be minimized.

[0025] In addition, the flame-retardant composite of the present application does not contain toxic substances such as halogens, and has the advantages of environmental friendliness and high flame-retardant efficiency. Therefore, the flame-retardant composite of the present application has the characteristics of environmental friendliness, high efficiency in flame retardancy, and excellent comprehensive performance, and can be applied to fields with high requirements for flame-retardant performance. Specific Embodiments

[0026] The following description provides specific application scenarios and requirements of the present application, aiming to enable those skilled in the art to manufacture and use the content of the present application. For those skilled in the art, various partial modifications to the disclosed embodiments are obvious, and the general principles defined here can be applied to other embodiments and applications without departing from the spirit and scope of the present application. Therefore, the present application is not limited to the disclosed embodiments, but has the broadest scope consistent with the claims.

[0027] The flame retardants used in flame-retardant PLA can be phosphorus-based flame retardants, such as ammonium polyphosphate (APP), aluminum hypophosphite (AHP), and their compounded flame-retardant systems, as well as synthetic novel phosphorus-nitrogen flame retardants, phosphonate flame retardants, phosphazene flame retardants, bio-based flame retardants, and some novel nano-flame retardants (the nano-flame retardants include: two-dimensional transition metal carbides (MXene), metal-organic framework materials (MOFs), graphene, carbon nanotubes, clay, nano-bio-based flame retardants, etc.). However, there are problems such as low efficiency and damage to mechanical properties.

[0028] Therefore, on the one hand, the present application provides a flame-retardant composite, which is obtained by taking a PLA / PBAT composite as the matrix and adding flame-retardant aerogel microspheres (FRA), phosphorus-containing epoxy, antioxidant, nucleating agent, and coupling agent through melt blending; by weight, the PLA / PBAT composite accounts for 85 parts to 97 parts, FRA accounts for 1 part to 5 parts, phosphorus-containing epoxy accounts for 0.5 part to 2 parts, antioxidant accounts for 0.01 part to 3 parts, nucleating agent accounts for 0.1 part to 2 parts, and coupling agent accounts for 1 part to 3 parts.

[0029] By adjusting the content of each component in the flame-retardant composite, the comprehensive performance of the formed flame-retardant composite can be improved. Among them, flame-retardant aerogel microspheres (FRA) and phosphorus-containing epoxy are used as flame retardants. If the addition amount is too high, it will cause agglomeration and a decrease in the mechanical properties of the flame-retardant composite. If the addition amount is too low, it cannot effectively play a role in the flame-retardant composite.

[0030] In some embodiments of the present application, the matrix is a composite of polylactic acid (PLA) and poly(butylene adipate-co-terephthalate) (PBAT), and the PLA / PBAT composite is obtained by physically blending polylactic acid and poly(butylene adipate-co-terephthalate) in different proportions. Among them, polylactic acid (PLA), also known as polyhydroxypropionic acid or polylactide, is a biodegradable polymer material formed by the polycondensation of lactic acid monomers, with the molecular formula (C3H6O3) x , where X is a positive integer greater than 1. Poly(butylene adipate-co-terephthalate) (PBAT) belongs to thermoplastic biodegradable plastics and is a copolymer of butylene adipate and butylene terephthalate, having both good ductility and elongation at break, as well as good heat resistance and impact performance.

[0031] In some embodiments of the present application, the weight ratio of polylactic acid to poly(butylene adipate-co-terephthalate) in the matrix is from 80:20 to 20:80, such as 70:30, 60:40, 50:50, 40:60, and 30:70, etc.

[0032] In some embodiments of the present application, the flame-retardant aerogel microspheres (FRA) are silica aerogel microspheres containing phosphorus-based flame-retardant groups. Among them, the structural formula of the silica aerogel microspheres containing phosphorus-based flame-retardant groups is:

[0033]

[0034] Among them, the R group includes:

[0035]

[0036] Or Any one or several of them.

[0037] The P-based flame-retardant groups in the flame-retardant aerogel microspheres FRA play a gas-phase flame-retardant effect during the combustion of the flame-retardant PLA / PBAT composite, releasing PO to interrupt the chain reaction, and the silicon-oxygen-silicon structure plays a condensed-phase flame-retardant effect, isolating heat and combustible gases.

[0038] The flame-retardant aerogel microspheres can be of nanoscale size. Among them, due to the characteristics of small size, good thermal stability, and being conducive to the formation of a dense carbon layer, the nano flame retardant has a good flame-retardant effect on the PLA / PBAT composite, and the nano flame retardant has the characteristics of less addition amount and good flame-retardant effect.

[0039] In some embodiments of the present application, the phosphorus-containing epoxy includes any one or more of the materials of Formula 1 to Formula 5 as follows.

[0040]

[0041] The phosphorus-containing epoxy material has a char-forming and coupling effect, synergistically with the flame-retardant and heat-insulating effects of FRA, improving the flame-retardant performance of the PLA / PBAT composite. Under the condition of maintaining a relatively high flame-retardant level, the addition amount of the flame retardant in the flame-retardant composite of the present application is greatly reduced.

[0042] In some embodiments of the present application, the antioxidant includes any one or more of pentaerythritol tetrakis(β-(3,5-di-tert-butyl-4-hydroxyphenyl))propionate, octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, diethyl 3,5-di-tert-butyl-4-hydroxybenzylphosphonate, and tris(2,4-di-tert-butylphenyl) phosphite. The antioxidant can effectively inhibit or reduce the rate of thermal oxidation reaction of the flame retardant composite, improve the processing resistance and heat resistance of the flame retardant composite, and delay the degradation and aging process of the flame retardant composite.

[0043] In some embodiments of the present application, the nucleating agent is at least one of ethylene bisstearamide (EBS), ethylene bis(hydroxystearamide) (EBH), 1,3,5-tribenzamide derivatives (BTA), lanthanum phenylphosphate, cerium phenylphosphate, montmorillonite, talc powder, and hydrazide compounds such as diphenyl adipate dihydrazide (TMC-306), diphenyl sebacate dihydrazide (TMC-300), and TMP3000 (produced by Hangzhou Xusheng New Materials Technology Co., Ltd.).

[0044] The nucleating agent promotes resin crystallization, increases the crystallization temperature, can shorten the molding cycle of the composite, increases the heat resistance temperature, improves mechanical properties, and increases surface gloss.

[0045] In some embodiments of the present application, the coupling agent is at least one or more of 3-aminopropyltrihydroxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, and N-β-(aminoethyl)-γ-aminopropyltriethoxysilane.

[0046] The coupling agent and the phosphorus-containing epoxy together play a coupling role, can improve the interfacial interaction, and minimize the impact on the mechanical properties of the PLA / PBAT composite.

[0047] The flame retardant PLA / PBAT composite described in the embodiments of the present application does not contain toxic substances such as halogens, and has the characteristics of environmental friendliness, high flame retardancy efficiency, and excellent comprehensive performance, and can be applied to fields with high flame retardancy requirements.

[0048] The embodiments of the present application also provide a method for preparing a flame retardant composite, including: melt-blending the matrix, the silica aerogel microspheres containing phosphorus-based flame retardant groups, the phosphorus-containing epoxy, the antioxidant, the nucleating agent, and the coupling agent.

[0049] The preparation method of the silica aerogel microspheres containing phosphorus-based flame retardant groups includes: being prepared by using a phosphorus-containing siloxane precursor through a sol-gel method, wherein the phosphorus-containing siloxane precursor includes any one or more of DPTK, DPHK, DPPK or DPTS. The molecular formulas of DPTK, DPHK, DPPK or DPTS are respectively shown as follows:

[0050]

[0051] In some embodiments of the present application, the phosphorus-containing siloxane precursor is synthesized from an aldehyde monomer, an amino siloxane and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO). In some embodiments of the present application, the aldehyde monomer includes terephthalaldehyde, p-hydroxybenzaldehyde, 5-hydroxymethylfurfural and thiophene-2-carboxaldehyde; the amino siloxane includes 3-aminopropyltrimethoxysilane and 3-aminopropyltriethoxysilane.

[0052] In some embodiments of the present application, the sol-gel method includes: dissolving the phosphorus-containing siloxane precursor in ethanol, adding deionized water for the first stirring, adjusting the pH value of the system to 2-3, and continuing the first stirring until hydrolysis to obtain a sol; pouring the sol into a pre-prepared mixed system of an oil phase and an emulsifier, performing the second stirring, adjusting the pH value of the system to 7-8, and then continuing the third stirring until wet gel microspheres are obtained; washing, filtering and aging the wet gel microspheres, and then forming the aerogel microspheres through solvent exchange and atmospheric drying; or washing, filtering, aging and freeze-drying the wet gel microspheres to form the aerogel microspheres.

[0053] In some embodiments of the present application, the first stirring is mechanical stirring, and the process conditions of the first stirring are: heating in a water bath at 50°C, the stirring rate is 300 r / min, and the stirring time is 10-20 min; the second stirring is mechanical stirring, and the process conditions of the second stirring are: heating in a water bath at 50°C, the stirring rate is 300 r / min, and the stirring time is 30 min; the third stirring is mechanical stirring, and the process conditions of the third stirring are: heating in a water bath at 50°C, the stirring rate is 450 r / min, and the stirring time is 40 min.

[0054] In some embodiments of the present application, the acid solution for adjusting the pH value of the system to 2-3 is selected from any one of 25% hydrochloric acid, nitric acid, oxalic acid, acetic acid; the alkali solution for adjusting the pH value of the system to 7-8 is selected from any one of 25% ammonia water and sodium hydroxide.

[0055] In some embodiments of the present application, the oil phase is any one of n - heptane, dimethyl silicone oil, kerosene, and vegetable oil; the emulsifier includes sorbitan monooleate, polysorbate, and co - emulsifier n - butanol, and the mass ratio of sorbitan monooleate to polysorbate is 9:1.

[0056] In some embodiments of the present application, in the mixed system of the oil phase and the emulsifier, the content of the emulsifier is 0.3 g / mL, and the volume ratio of the mixed solution of ethanol and deionized water to the oil phase is 1:3.

[0057] In some embodiments of the present application, the washing and filtration are carried out by suction filtration with anhydrous ethanol for 3 times; the process conditions for aging are: water - bath heating at 50 °C and soaking in ethanol for 1 - 3 h; the process conditions for solvent exchange are: removing residual moisture, water - bath heating at 50 °C, and soaking in n - hexane for 1 - 3 h; the process conditions for atmospheric drying are: atmospheric drying at 80 °C for 6 - 10 h; the process conditions for freeze - drying are: first pre - freezing, and then freeze - drying in a freeze - dryer to obtain the aerogel microspheres.

[0058] By the above method, flame - retardant aerogel microspheres FRA1, FRA2, FRA3, and FRA4 can be prepared by the sol - gel method from phosphorus - containing siloxane precursors DPTK, DPHK, DPPK, and DPTS respectively.

[0059] The improvement of the flame - retardant performance of the flame - retardant composite in the present application is mainly due to the fact that PO· free radicals are generated during the combustion process of the composite material, which can capture the active H· and OH· free radicals generated during the combustion process, interrupt the chain reaction, and achieve the effect of gas - phase flame retardancy. The combustion of the silicon - oxygen - silicon structure will form a physical barrier, covering the surface of the matrix, isolating heat transfer and the release of combustible gases, and achieving the effect of condensed - phase flame retardancy.

[0060] The embodiments of the present application will be further described in detail below through Examples 1 to 22.

[0061] Example 1:

[0062] PLA / PBAT composite (80 wt%: 20 wt%), the flame-retardant aerogel microspheres are FRA1, the phosphorus-containing epoxy is of Formula 1, the antioxidant is a commercial antioxidant with the trade name 1010 (chemical name: pentaerythritol tetrakis(β-(3,5-di-tert-butyl-4-hydroxyphenyl))propionate), the nucleating agent is ethylene bisstearamide (EBS), and the coupling agent is 3-aminopropyltrihydroxysilane. Using the PLA / PBAT composite as the matrix, adding FRA, phosphorus-containing epoxy, antioxidant, nucleating agent, and coupling agent, a halogen-free flame-retardant PLA / PBAT composite is obtained through melt blending; by weight, the total weight is 100 parts, among which the PLA / PBAT composite is 96.67 parts, FRA is 1 part, the phosphorus-containing epoxy is 1 part, the antioxidant is 0.03 part, the nucleating agent is 0.3 part, and the coupling agent is 1 part.

[0063] Example 2:

[0064] PLA / PBAT composite (70 wt%: 30 wt%), the flame-retardant aerogel microspheres are FRA2, the phosphorus-containing epoxy is of Formula 2, the antioxidant is a commercial antioxidant with the trade name 1076 (chemical name: octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate), the nucleating agent is ethylene hydroxydistearamide (EBH), and the coupling agent is 3-aminopropyltriethoxysilane. Using the PLA / PBAT composite as the matrix, adding FRA, phosphorus-containing epoxy, antioxidant, nucleating agent, and coupling agent, a halogen-free flame-retardant PLA / PBAT composite is obtained through melt blending; by weight, the total weight is 100 parts, among which the PLA / PBAT composite is 85 parts, FRA is 5 parts, the phosphorus-containing epoxy is 2 parts, the antioxidant is 3 parts, the nucleating agent is 2 parts, and the coupling agent is 3 parts.

[0065] Example 3:

[0066] PLA / PBAT composite (60 wt%: 40 wt%), the flame-retardant aerogel microspheres are FRA2, the phosphorus-containing epoxy is of Formula 2, the antioxidant is a commercial antioxidant with the trade name 1076, the nucleating agent is ethylene hydroxydistearamide (EBH), and the coupling agent is 3-aminopropyltriethoxysilane. Using the PLA / PBAT composite as the matrix, adding FRA, phosphorus-containing epoxy, antioxidant, nucleating agent, and coupling agent, a halogen-free flame-retardant PLA / PBAT composite is obtained through melt blending; by weight, the total weight is 100 parts, among which the PLA / PBAT composite is 88.5 parts, FRA is 4 parts, the phosphorus-containing epoxy is 2 parts, the antioxidant is 2 parts, the nucleating agent is 1.5 parts, and the coupling agent is 2 parts.

[0067] Example 4:

[0068] PLA / PBAT composite (50 wt%: 50 wt%), the flame-retardant aerogel microspheres are FRA3, the phosphorus-containing epoxy is Formula 3, the antioxidant is a commercial antioxidant with the trade name 1222 (chemical name: diethyl (3,5-di-tert-butyl-4-hydroxybenzyl) phosphate), the nucleating agent is 1,3,5-tribenzamide derivative (BTA), and the coupling agent is 3-aminopropyltrimethoxysilane. Using the PLA / PBAT composite as the matrix, adding FRA, phosphorus-containing epoxy, antioxidant, nucleating agent, and coupling agent, a halogen-free flame-retardant PLA / PBAT composite is obtained through melt blending; by weight, the total weight is 100 parts, among which the PLA / PBAT composite is 93 parts, FRA is 3 parts, phosphorus-containing epoxy is 1 part, antioxidant is 1 part, nucleating agent is 1 part, and coupling agent is 1 part.

[0069] Example 5:

[0070] PLA / PBAT composite (40 wt%: 60 wt%), the flame-retardant aerogel microspheres are FRA4, the phosphorus-containing epoxy is Formula 4, the antioxidant is a commercial antioxidant with the trade name 168 (chemical name: tris(2,4-di-tert-butylphenyl) phosphite), the nucleating agent is lanthanum phenylphosphate, and the coupling agent is N-β(aminoethyl)-γ-aminopropyltrimethoxysilane. Using the PLA / PBAT composite as the matrix, adding FRA, phosphorus-containing epoxy, antioxidant, nucleating agent, and coupling agent, a halogen-free flame-retardant PLA / PBAT composite is obtained through melt blending; by weight, the total weight is 100 parts, among which the PLA / PBAT composite is 94.5 parts, FRA is 2 parts, phosphorus-containing epoxy is 1.5 parts, antioxidant is 0.5 part, nucleating agent is 0.5 part, and coupling agent is 1 part.

[0071] Example 6:

[0072] PLA / PBAT composite (30 wt%: 70 wt%), the flame-retardant aerogel microspheres are FRA1, the phosphorus-containing epoxy is Formula 5, the antioxidant is a commercial antioxidant with the trade names 1010 and 168 (weight ratio 2:1), the nucleating agent is cerium phenylphosphate, and the coupling agent is N-β(aminoethyl)-γ-aminopropyltriethoxysilane. Using the PLA / PBAT composite as the matrix, adding FRA, phosphorus-containing epoxy, antioxidant, nucleating agent, and coupling agent, a halogen-free flame-retardant PLA / PBAT composite is obtained through melt blending; by weight, the total weight is 100 parts, among which the PLA / PBAT composite is 96 parts, FRA is 1 part, phosphorus-containing epoxy is 1 part, antioxidant is 0.5 part, nucleating agent is 0.5 part, and coupling agent is 1 part.

[0073] Example 7:

[0074] PLA / PBAT composite (20 wt%: 80 wt%), the flame-retardant aerogel microspheres are FRA2, the phosphorus-containing epoxy is of formula 4, the antioxidants are commercial antioxidants of grade 1010 and 1076 (weight ratio 2:1), the nucleating agent is montmorillonite, and the coupling agent is N-β(aminoethyl)-γ-aminopropyltriethoxysilane. Using the PLA / PBAT composite as the matrix, adding FRA, phosphorus-containing epoxy, antioxidants, nucleating agent, and coupling agent, a halogen-free flame-retardant PLA / PBAT composite is obtained through melt blending; by weight, the total weight is 100 parts, among which the PLA / PBAT composite is 96.85 parts, FRA is 1 part, the phosphorus-containing epoxy is 0.5 part, the antioxidants are 0.05 part, the nucleating agent is 0.1 part, and the coupling agent is 1.5 parts.

[0075] Example 8:

[0076] PLA / PBAT composite (30 wt%: 70 wt%), the flame-retardant aerogel microspheres are FRA3, the phosphorus-containing epoxy is of formula 3, the antioxidants are commercial antioxidants of grade 1010 and 1222 (weight ratio 2:1), the nucleating agent is talc powder, and the coupling agent is 3-aminopropyltrihydroxysilane and N-β(aminoethyl)-γ-aminopropyltrimethoxysilane (weight ratio 2:1). Using the PLA / PBAT composite as the matrix, adding FRA, phosphorus-containing epoxy, antioxidants, nucleating agent, and coupling agent, a halogen-free flame-retardant PLA / PBAT composite is obtained through melt blending; by weight, the total weight is 100 parts, among which the PLA / PBAT composite is 94.95 parts, FRA is 2 parts, the phosphorus-containing epoxy is 1 part, the antioxidants are 0.05 part, the nucleating agent is 0.5 part, and the coupling agent is 1.5 parts.

[0077] Example 9:

[0078] PLA / PBAT composite (40 wt%: 60 wt%), the flame-retardant aerogel microspheres are FRA4, the phosphorus-containing epoxy is of formula 2, the antioxidants are commercial antioxidants of grade 1010 and 168 (weight ratio 2:1), the nucleating agent is TMC-300, and the coupling agent is 3-aminopropyltriethoxysilane and N-β(aminoethyl)-γ-aminopropyltriethoxysilane (weight ratio 2:1). Using the PLA / PBAT composite as the matrix, adding FRA, phosphorus-containing epoxy, antioxidants, nucleating agent, and coupling agent, a halogen-free flame-retardant PLA / PBAT composite is obtained through melt blending; by weight, the total weight is 100 parts, among which the PLA / PBAT composite is 93.5 parts, FRA is 3 parts, the phosphorus-containing epoxy is 1.5 parts, the antioxidants are 0.1 part, the nucleating agent is 0.9 part, and the coupling agent is 1 part.

[0079] Example 10:

[0080] PLA / PBAT composite (50 wt%: 50 wt%), the flame-retardant aerogel microspheres are FRA1, the phosphorus-containing epoxy is of Formula 1, the antioxidant is a commercial antioxidant of grades 1076 and 168 (weight ratio 2:1), the nucleating agent is TMC-306, and the coupling agents are 3-aminopropyltrimethoxysilane and N-β(aminoethyl)-γ-aminopropyltriethoxysilane (weight ratio 2:1). Using the PLA / PBAT composite as the matrix, adding FRA, phosphorus-containing epoxy, antioxidant, nucleating agent, and coupling agent, a halogen-free flame-retardant PLA / PBAT composite is obtained through melt blending; by weight parts, the total weight parts is 100 parts, among which the PLA / PBAT composite is 92.5 parts, FRA is 3 parts, the phosphorus-containing epoxy is 2 parts, the antioxidant is 0.2 parts, the nucleating agent is 0.8 parts, and the coupling agent is 1.5 parts.

[0081] Example 11:

[0082] PLA / PBAT composite (60 wt%: 40 wt%), the flame-retardant aerogel microspheres are FRA2, the phosphorus-containing epoxy is of Formula 2, the antioxidant is a commercial antioxidant of grades 1022 and 168 (weight ratio 1:2), the nucleating agent is TMP3000, and the coupling agents are 3-aminopropyltrimethoxysilane and N-β(aminoethyl)-γ-aminopropyltrimethoxysilane (weight ratio 1:1). Using the PLA / PBAT composite as the matrix, adding FRA, phosphorus-containing epoxy, antioxidant, nucleating agent, and coupling agent, a halogen-free flame-retardant PLA / PBAT composite is obtained through melt blending; by weight parts, the total weight parts is 100 parts, among which the PLA / PBAT composite is 92 parts, FRA is 4 parts, the phosphorus-containing epoxy is 1.5 parts, the antioxidant is 0.3 parts, the nucleating agent is 0.7 parts, and the coupling agent is 1.5 parts.

[0083] Example 12:

[0084] PLA / PBAT composite (70 wt%: 30 wt%), the flame-retardant aerogel microspheres are FRA3, the phosphorus-containing epoxy is of Formula 3, the antioxidant is a commercial antioxidant of grades 1010 and 168 (weight ratio 1:2), the nucleating agent is TMP300, and the coupling agents are 3-aminopropyltrimethoxysilane and N-β(aminoethyl)-γ-aminopropyltriethoxysilane (weight ratio 1:1). Using the PLA / PBAT composite as the matrix, adding FRA, phosphorus-containing epoxy, antioxidant, nucleating agent, and coupling agent, a halogen-free flame-retardant PLA / PBAT composite is obtained through melt blending; by weight parts, the total weight parts is 100 parts, among which the PLA / PBAT composite is 91 parts, FRA is 4 parts, the phosphorus-containing epoxy is 2 parts, the antioxidant is 0.5 parts, the nucleating agent is 1 part, and the coupling agent is 1.5 parts.

[0085] Example 13:

[0086] PLA / PBAT compound (80wt%: 20wt%), flame retardant gas gel microspheres are FRA4, phosphorus-containing epoxy is formula 5, antioxidants are commercial antioxidants of grades 1010 and 168 (weight ratio 1: 2), nucleating agent is TMP300, coupling agent is 3-aminopropyltrimethoxysilane and N-β (aminoethyl) -γ-aminopropyltriethoxysilane (weight ratio 1: 1). PLA / PBAT compound is used as the matrix, FRA, phosphorus-containing epoxy, antioxidant, nucleating agent, coupling agent are added, and halogen-free flame retardant PLA / PBAT compound is obtained by melt blending; according to weight parts, the total weight parts are 100 parts, including 90 parts of PLA / PBAT compound, 4.5 parts of FRA, 2.0 parts of phosphorus-containing epoxy, 1 part of antioxidant, 1 part of nucleating agent, and 1.5 parts of coupling agent.

[0087] Embodiment 14:

[0088] The nucleating agent is ethylene bis stearamide (EBS) and lanthanum phenyl phosphate (weight ratio 2:1), and the other ingredients and contents are the same as those in Example 1.

[0089] Embodiment 15:

[0090] The nucleating agent is ethylene hydroxybisstearamide (EBH) and cerium phenyl phosphate (weight ratio 1:2), and the other ingredients and contents are the same as those in Example 2.

[0091] Embodiment 16:

[0092] The nucleating agent is 1,3,5-tribenzamide derivative (BTA) and montmorillonite (weight ratio 2:1), and the other components and contents are the same as those in Example 4.

[0093] Embodiment 17:

[0094] The nucleating agent is 1,3,5-tribenzamide derivative (BTA) and talc (weight ratio 2:1), and the other ingredients and contents are the same as those in Example 5.

[0095] Embodiment 18:

[0096] The nucleating agent is ethylene bisstearamide (EBS) and TMP300 (weight ratio 1:1), and the other ingredients and contents are the same as those in Example 6.

[0097] Embodiment 19:

[0098] The nucleating agent is ethylene hydroxybisstearamide (EBH) and TMP3000 (weight ratio 1:1), and the other ingredients and contents are the same as those in Example 7.

[0099] Embodiment 20:

[0100] The nucleating agent is 1,3,5-tribenzamide derivative (BTA) and TMC-306 (weight ratio 1:1), and the remaining components and their contents are the same as those in Example 8.

[0101] Example 21:

[0102] The nucleating agent is montmorillonite and TMC-306 (weight ratio 1:2), and the remaining components and their contents are the same as those in Example 9.

[0103] Example 22:

[0104] The nucleating agent is talc powder and TMP300 (weight ratio 1:2), and the remaining components and their contents are the same as those in Example 10.

[0105] The flame retardancy and mechanical properties of the above Examples 1 to 22 were tested. The LOI was tested according to GB / T 2406-2009, and the vertical burning was tested according to UL94-1996. The test results are shown in Table 1 below.

[0106] Table 1

[0107]

[0108]

[0109] Among them, NC refers to no rating in the vertical burning test according to the UL94-1996 standard, and V0, V1, and V2 respectively refer to the three flame retardant ratings of the obtained materials in the vertical burning test according to the UL94-1996 standard.

[0110] Finally, it should be understood that the embodiments of the application disclosed herein are illustrative of the principles of the embodiments of the application. Other modified embodiments are also within the scope of the present application. Therefore, the embodiments disclosed in the present application are merely examples and not limitations. Those skilled in the art can adopt alternative configurations according to the embodiments in the present application to implement the application in the present application. Therefore, the embodiments of the present application are not limited to those embodiments precisely described in the application.

Claims

1. A flame-retardant composite, characterized in that, Comprising: A matrix, which is a composite of polylactic acid and polybutylene adipate / terephthalate; Flame-retardant aerogel microspheres; Phosphorus-containing epoxy; Antioxidant; Nucleating agent; And coupling agent; By weight, the matrix accounts for 85 parts to 97 parts, the flame-retardant aerogel microspheres account for 1 part to 5 parts, the phosphorus-containing epoxy accounts for 0.5 part to 2 parts, the antioxidant accounts for 0.01 part to 3 parts, the nucleating agent accounts for 0.1 part to 2 parts, and the coupling agent accounts for 1 part to 3 parts. Among them, the flame-retardant aerogel microspheres are silica aerogel microspheres containing phosphorus-based flame-retardant groups, and the structural formula of the silica aerogel microspheres containing phosphorus-based flame-retardant groups is: Among them, the R group includes: or any one or more of; the phosphorus-containing epoxy resin includes: or any one or more of them.

2. The flame retardant composite according to claim 1, wherein The antioxidant includes any one or more of pentaerythritol tetrakis(β-(3,5-di-tert-butyl-4-hydroxyphenyl))propionate, octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, diethyl (3,5-di-tert-butyl-4-hydroxybenzyl)phosphonate, and tris(2,4-di-tert-butylphenyl)phosphite.

3. The flame retardant composite according to claim 1, characterized in that, The nucleating agent is at least one of ethylene bisstearamide, ethylene hydroxydistearamide, lanthanum phenylphosphate, cerium phenylphosphate, montmorillonite, talc powder, diphenyl sebacyl diimide, or diphenyl adipyl diimide.

4. The flame retardant composite according to claim 1, wherein, The coupling agent is at least one or more of 3-aminopropyltrihydroxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, N-β(aminoethyl)-γ-aminopropyltrimethoxysilane, and N-β(aminoethyl)-γ-aminopropyltriethoxysilane; The weight ratio of polylactic acid to polybutylene adipate / terephthalate in the matrix is 80:20 - 20:

80.

5. The preparation method of the flame-retardant composite according to any one of claims 1 to 4, characterized in that, Comprising: Melting and blending the matrix, the flame-retardant aerogel microspheres, the phosphorus-containing epoxy, the antioxidant, the nucleating agent, and the coupling agent.

6. The method for preparing a flame retardant composite according to claim 5, characterized in that, The flame-retardant aerogel microspheres are silica aerogel microspheres containing phosphorus-based flame-retardant groups. The method for forming the silica aerogel microspheres containing phosphorus-based flame-retardant groups includes: Using a phosphorus-containing siloxane precursor and preparing it by the sol-gel method. Among them, the phosphorus-containing siloxane precursor includes and any one or more of 7. The method for preparing the flame retardant composite according to claim 6, characterized in that, The sol-gel method includes: Dissolving the phosphorus-containing siloxane precursor in ethanol, adding deionized water for the first stirring, adjusting the pH of the system to 2 - 3, and continuing the first stirring until hydrolysis to obtain a sol; Pouring the sol into a pre-prepared mixed system of oil phase and emulsifier, performing the second stirring, adjusting the pH of the system to 7 - 8, and then continuing the third stirring until wet gel microspheres are obtained; Washing, filtering, and aging the wet gel microspheres, and then forming the flame-retardant aerogel microspheres through solvent exchange and atmospheric drying; or washing, filtering, aging, and freeze-drying the wet gel microspheres to form the flame-retardant aerogel microspheres.

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