Preparation method and application of degradable candle container

Abstract

The invention belongs to the technical field of candle accessories, and particularly relates to a preparation method and application of a degradable candle container. The degradable candle container provided by the invention is prepared from the following raw materials in parts by mass: 60-100 parts of polylactic acid, 5-20 parts of filler, 5-20 parts of an environment-friendly flame retardant, 1-6 parts of a flame-retardant synergist and 0-7 parts of a performance additive, the modification additive comprises one or two of a polylactic acid modification additive and a filler modification additive; the polylactic acid modification auxiliary agent comprises one or two of maleic anhydride and dicumyl peroxide; the filler modification additive comprises one or more of a silane coupling agent and an alkali metal hydroxide solution; the filler comprises one or more of hemp, fiber and agricultural waste. The degradable candle container obtained by the invention not only has good flame retardant property, but also has excellent biodegradability and good processability and mechanical property, and can ensure the safety of candle combustion.

Description

Technical Field

[0001] The invention belongs to the field of candle accessories, and in particular relates to a preparation method and application of a degradable candle container. Background Art

[0002] At present, common materials for candle containers include glass, ceramics, plastics and metals. Glass, ceramics and metal candle containers consume high energy during the production process, which is not conducive to sustainable development. Plastic candle containers are non-degradable after being discarded, causing certain pollution to the environment. However, the flame retardant properties of existing degradable materials cannot meet the use requirements of candle containers. In order to solve the above problems, degradable candle containers have attracted the attention of researchers. At present, a variety of degradable materials have been introduced at home and abroad, mainly starch, dual-degradable plastics, pulp molding and biomass degradable materials, etc. Most of them are used to make lunch boxes and flower pots, etc., and candle containers made of degradable materials have not yet been introduced.

[0003] In recent years, plant short fiber-biobased composite materials have gradually emerged as new materials. They are biodegradable. The raw materials are taken from plant fibers such as crop straw short fibers and bamboo short fibers, and are compounded with bio-based resins such as modified starch, soy protein glue and polylactic acid to form bio-based degradable materials. Various containers are made by molding and injection molding. According to the type of matrix material, plant short fiber-biobased composite materials can be divided into starch-based plant short fiber type, soy protein-based plant short fiber type and polylactic acid-based plant short fiber type.

[0004] Polylactic acid is the most widely used plant short fiber-biobased composite material. It is an aliphatic polyester produced by the polymerization reaction of lactic acid produced by fermentation of renewable resources such as corn and potatoes. Polylactic acid has excellent physical and chemical properties, such as biodegradability, easy processing and good transparency, but polylactic acid itself is extremely flammable and produces molten droplets, leading to secondary combustion. Summary of the invention

[0005] The purpose of the present invention is to provide a preparation method and application of a degradable candle container. The degradable candle container provided by the present invention has excellent flame retardancy and biodegradability.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] The present invention provides a degradable candle container, which is prepared from the following raw materials in parts by weight:

[0008] 60-100 parts of polylactic acid, 5-20 parts of filler, 5-20 parts of environmentally friendly flame retardant, 1-6 parts of flame retardant synergist and 0-7 parts of modification additive;

[0009] The modification aid includes one or both of a polylactic acid modification aid and a filler modification aid;

[0010] The polylactic acid modification aid includes one or both of maleic anhydride and dicumyl peroxide; the filler modification aid includes one or both of silane coupling agent and alkali metal hydroxide solution;

[0011] The filler comprises one or more of hemp, fiber and agricultural waste.

[0012] Preferably, the environmentally friendly flame retardant includes an acid source, a carbon source and a gas source; the acid source includes one or more of ammonium polyphosphate, ammonium salt and inorganic acid; the carbon source includes one or more of starch, dextrin, cellulose, polyol and alcohol; and the gas source is amine.

[0013] Preferably, the mass ratio of the acid source to the carbon source in the environmentally friendly flame retardant is 1-5:1-3, and the mass ratio of the carbon source to the gas source is 1-3:1-3.

[0014] Preferably, the polylactic acid includes one or more of poly DL-lactic acid and poly L-lactic acid; the viscosity average molecular weight of the polylactic acid is 1,000 to 300,000.

[0015] Preferably, the particle size of the filler is 10 to 100 meshes.

[0016] Preferably, the flame retardant synergist includes one or more of layered double hydroxide, modified montmorillonite and expandable graphite.

[0017] Preferably, the hemp includes one or more of kenaf, hemp, flax, jute and sisal; the fiber is one or two of bamboo fiber and reed; the agricultural waste includes one or more of wheat straw powder, sugarcane straw powder, rice husk powder and rice straw powder.

[0018] The present invention also provides a method for preparing the degradable candle container of the above scheme. When the modification aid is a filler modification aid, the preparation method comprises the following steps:

[0019] (1) mixing and modifying a filler and a modifying aid, and then drying the modified filler, polylactic acid, a flame retardant synergist, and an environmentally friendly flame retardant to obtain a mixture;

[0020] (2) The mixed material is compression molded to obtain a degradable candle container.

[0021] The present invention also provides a method for preparing the degradable candle container of the above scheme. When the modification aid is a polylactic acid modification aid, the preparation method comprises the following steps:

[0022] (1) mixing polylactic acid and a modifying aid, performing a melt grafting reaction, and then crushing and drying to obtain modified polylactic acid;

[0023] (2) melt-mixing the modified polylactic acid, filler, flame retardant synergist and environmentally friendly flame retardant and then crushing them to obtain a mixture;

[0024] (3) The mixed material is compression molded to obtain a degradable candle container.

[0025] The present invention also provides the use of the degradable candle container described in the above scheme or the degradable candle container obtained by the preparation method described in the above scheme in candle accessories.

[0026] The invention provides a degradable candle container, which is prepared from the following raw materials in parts by mass: 60-100 parts of polylactic acid, 5-20 parts of filler, 5-20 parts of environmentally friendly flame retardant, 1-6 parts of flame retardant synergist and 1.8-7 parts of modification aid; the modification aid includes one or both of a polylactic acid modification aid and a filler modification aid; the polylactic acid modification aid includes one or both of maleic anhydride and diisopropylbenzene peroxide; the filler modification aid includes one or more of a silane coupling agent and an alkali metal hydroxide solution; the filler includes one or more of hemp, fiber and agricultural waste. The present invention overcomes the problem of two-phase dispersion and reduces the material cost of the container by adding fillers and filler modification additives and / or polylactic acid modification additives. The flame retardant efficiency is improved while reducing the amount of flame retardant added by using an environmentally friendly flame retardant and a flame retardant synergist in combination. The finally obtained degradable candle container not only has good flame retardant performance, but also has a burning time of no more than 11 seconds and a total burning time of no more than 125 seconds, which are much shorter than the requirements of the candle fire safety standard for the burning time. The combustion test UV94 is V0 level, and the biodegradability is excellent, the degradation time is 2.5 to 3 years, and the processing performance and mechanical properties are good. The raw material source is wide, the cost is low, and the good economic and social benefits are achieved.

[0027] Furthermore, the present invention can better solve the problem of two-phase dispersion by limiting the particle size of the filler.

[0028] Furthermore, the present invention increases the environmental performance of the material by using starch, dextrin, cellulose, polyol and alcohol as carbon sources, and can further enhance the flame retardant performance of the candle container and reduce the use of flame retardants.

[0029] The present invention also provides a method for preparing the degradable candle container of the above scheme. In the present invention, polylactic acid and various additives are mixed by melt mixing, so that the components are fully mixed, the steps are simple, the operation is convenient, the material molding cycle is short, the production efficiency is improved, and it is easy to mass produce.

[0030] The present invention also provides the use of the degradable candle container described in the above scheme or the degradable candle container obtained by the preparation method described in the above scheme in candle accessories. The present invention adds an environmentally friendly composite additive to the degradable material, and the obtained degradable candle container is used in the field of candle accessories, which can ensure the safety of candle burning and prevent the candle container from being ignited, thereby broadening the application field of degradable materials, especially degradable polylactic acid. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0032] Figure 1 The appearance of the degradable candle containers prepared in Example 1 (left) and Example 2 (right) of the present invention when no candles are poured;

[0033] Figure 2 Appearance of the degradable candle containers prepared in Example 3 (left) and Example 4 (right) of the present invention after pouring candles. DETAILED DESCRIPTION

[0034] The present invention provides a degradable candle container, which is prepared from the following raw materials in parts by weight:

[0035] 60-100 parts of polylactic acid, 5-20 parts of filler, 5-20 parts of environmentally friendly flame retardant, 1-6 parts of flame retardant synergist and 0-7 parts of modification additive;

[0036] The modification aid includes one or both of a polylactic acid modification aid and a filler modification aid;

[0037] The polylactic acid modification aid includes one or both of maleic anhydride and dicumyl peroxide; the filler modification aid includes one or both of silane coupling agent and alkali metal hydroxide solution;

[0038] The filler comprises one or more of hemp, fiber and agricultural waste.

[0039] In parts by mass, the raw materials of the degradable candle container provided by the present invention include 60 to 100 parts of polylactic acid, preferably 70 to 90 parts, and more preferably 75 to 85 parts; the polylactic acid preferably includes one or more of poly DL-lactic acid and poly L-lactic acid; the viscosity-average molecular weight of the polylactic acid is preferably 1000 to 300000, more preferably 10000 to 200000, and further preferably 20000 to 150000.

[0040] Based on the mass parts of the polylactic acid, the raw materials of the degradable candle container provided by the present invention include 5 to 20 parts of filler, preferably 7 to 18 parts, and more preferably 10 to 15 parts; the filler includes one or more of hemp, fiber and agricultural waste; the hemp preferably includes one or more of kenaf, hemp, flax, jute and sisal; the fiber is preferably one or two of bamboo fiber and reed; the agricultural waste preferably includes one or more of wheat straw powder, sugarcane straw powder, rice husk powder and rice straw powder; the filler is more preferably one or two of kenaf and rice husk powder; the particle size of the filler is preferably 10 to 100 meshes, more preferably 20 to 80 meshes, and further preferably 40 to 60 meshes.

[0041] Based on the mass parts of the polylactic acid, the raw materials of the degradable candle container provided by the present invention include 5 to 20 parts of an environmentally friendly flame retardant, preferably 7 to 18 parts, and more preferably 10 to 14 parts; the environmentally friendly flame retardant preferably includes an acid source, a carbon source and a gas source; the acid source preferably includes one or more of ammonium polyphosphate, an ammonium salt and an inorganic acid; the relative molecular mass of the ammonium polyphosphate is preferably greater than 2000, more preferably 2000 to 10000, and further preferably 4000 to 8000; the ammonium salt preferably includes one or more of ammonium sulfate, ammonium chloride, ammonium phosphate and ammonium borate; the inorganic acid preferably includes one or more of boric acid, sulfuric acid and phosphoric acid. In the present invention, the acid source more preferably includes one or more of ammonium polyphosphate and boric acid; the carbon source preferably includes starch, dextrin, , cellulose, polyol and alcohol; the cellulose preferably includes one or more of carboxymethyl cellulose and hydroxypropyl cellulose; the polyol preferably includes one or both of polyethylene glycol and polyvinyl alcohol; the alcohol preferably includes one or both of butanediol and methanol; the carbon source is more preferably one or both of dextrin and polyethylene glycol; the gas source is preferably an amine; the amine preferably includes one or more of melamine, melamine cyanurate, dicyandiamide and urea, more preferably melamine; the mass ratio of the acid source to the carbon source in the environmentally friendly flame retardant is preferably 1-5:1-3, more preferably 2-3:1-2, and further preferably 3:1; the mass ratio of the carbon source to the gas source is preferably 1-3:1-3, more preferably 1-2:1-2, and further preferably 1:1.

[0042] Based on the mass parts of the polylactic acid, the raw materials of the degradable candle container provided by the present invention include 1 to 6 parts of a flame retardant synergist, preferably 2 to 5 parts, and more preferably 3 to 4 parts; the flame retardant synergist preferably includes one or more of a layered double hydroxide (LDH), a layered silicate, a modified montmorillonite (O-MMT) and an expandable graphite (EG); the layered double hydroxide preferably includes one or more of a layered magnesium aluminum double metal hydroxide, an organically modified FeAl-LDH and an organically modified ZnAl-LDH; the The layered silicate preferably includes one or more of talc, mica, asbestos, and kaolinite; the modified montmorillonite is preferably inorganic modified montmorillonite; the inorganic modified montmorillonite preferably includes one or more of quaternary phosphonium salt-montmorillonite and sodium salt-montmorillonite; the particle size of the expandable graphite is preferably 5μm to 5mm, more preferably 100μm to 3mm, and further preferably 500μm to 2mm; the flame retardant synergist is more preferably one or more of layered double hydroxide (LDH) and modified montmorillonite (O-MMT). The flame retardant synergist of the present invention and the environmentally friendly flame retardant act synergistically to improve the flame retardant properties of the degradable candle container.

[0043] In the present invention, the preparation method of the organic modified ZnAl-LDH preferably comprises the following steps: mixing a metal salt solution and an organic acid salt solution, adjusting the pH of the mixed solution to 8 to 10 for a synthesis reaction, and then aging to obtain an organic modified ZnAl-LDH. In the present invention, the metal salt in the metal salt solution preferably comprises a zinc salt and an aluminum salt; the zinc salt preferably comprises one or both of zinc sulfate and zinc phosphate; the aluminum salt preferably comprises one or both of aluminum sulfate and aluminum phosphate; the zinc salt and the aluminum salt (Zn 2+ :Al 3+ ) is preferably 1-5:0.5-3, more preferably 2:1; the concentration of the metal salt solution is preferably 0.1-3 mol / L, more preferably 0.5-2 mol / L; the organic acid salt in the organic acid salt solution preferably includes one or more of sodium dodecylbenzene sulfonate and alkyl sulfonates; the alkyl sulfonates preferably include one or two of sodium dodecyl sulfonate and sodium hexadecyl sulfonate; the concentration of the organic acid salt solution is preferably 0.1-3wt%, more preferably 0.5-2wt%; the volume ratio of the metal salt solution to the organic acid salt solution is preferably 1-5:0.1-2, more preferably 2-4:0.5-1.5; the mixing is preferably performed by dropping the metal salt solution into the organic acid salt solution; the dropping rate is preferably 10-80 drops / minute, more preferably 20-50 drops / minute.

[0044] In the present invention, the preparation method of the organically modified FeAl-LDH is consistent with the preparation method of the organically modified ZnAl-LDH, except that the metal salt in the metal salt solution preferably includes an iron salt and an aluminum salt.

[0045] In the present invention, the temperature of the synthesis reaction is preferably 35-65°C, more preferably 35-50°C, the time is preferably 10-120min, more preferably 40-80min, and the time of the synthesis reaction is counted from the time when the metal salt solution is completely added dropwise to the organic acid salt solution; the synthesis reaction is preferably carried out under stirring; the stirring rate is preferably 100-400r / min, more preferably 200-300r / min, and the stirring time is preferably 20-60min, more preferably 30-45min; the pH of the mixed solution is adjusted to 8-10, preferably 8.9-9.1, more preferably 9.0; the reagent for adjusting the pH of the mixed solution is preferably a strong alkali solution; the strong alkali solution preferably includes one or more of a sodium hydroxide solution and a potassium hydroxide solution. Two kinds; the concentration of the strong alkaline solution is preferably 0.1-2.5 mol / L, more preferably 0.5-2.0 mol / L; the aging temperature is preferably 55-65°C, more preferably 58-60°C, and the time is preferably 12-24h, more preferably 18h; after the aging is completed, the product is preferably filtered, washed and dried in sequence; the washing reagent is preferably distilled water to remove unreacted raw materials until the pH value of the supernatant is 6.5-7.5, more preferably 7; the drying temperature is 60-80°C, preferably 65-75°C, more preferably 70°C, and the time is preferably 2-12h, more preferably 4-8h, until constant weight is reached; the moisture content of the product obtained by drying is preferably no more than 3wt%, more preferably 0.1wt%-2wt%.

[0046] Based on the mass parts of the polylactic acid, the raw materials of the degradable candle container provided by the present invention include 0 to 7 parts of a modification aid, more preferably 1.8 to 6 parts, and further preferably 4 to 5 parts; the modification aid includes one or both of a polylactic acid modification aid and a filler modification aid; the polylactic acid modification aid includes one or both of maleic anhydride and dicumyl peroxide (DCP); the filler modification aid includes one or more of a silane coupling agent and an alkali metal hydroxide solution; the silane coupling agent preferably includes vinyl trimethoxysilane, vinyl tris (2-methoxyethoxy) silane, vinyl trichlorosilane, One or more of silane coupling agent KH570, silane coupling agent KH-550, silane coupling agent KH-560, silane coupling agent KH570, silane coupling agent KH580, silane coupling agent KH590 and silane coupling agent KH-792; the alkali metal hydroxide solution preferably includes one or more of sodium hydroxide solution and potassium hydroxide solution; the concentration of the alkali metal hydroxide solution is preferably 0.1-2 mol / L, more preferably 0.5-1.5 mol / L; the modification aid is more preferably one or more of maleic anhydride, silane coupling agent KH570 and sodium hydroxide aqueous solution. The addition of the modification aid in the present invention is conducive to overcoming the dispersion problem of the filler, increasing the hardness of the degradable candle container, improving the molding rate and anti-leakage property of the degradable candle container, and diisopropylbenzene peroxide can improve the heat resistance and aging resistance of the degradable candle container.

[0047] In the present invention, when the modifying agent is a filler modifying agent, the preparation method of the degradable candle container comprises the following steps:

[0048] (1) mixing and modifying a filler and a modifying aid, and then drying the modified filler, polylactic acid, a flame retardant synergist, and an environmentally friendly flame retardant to obtain a mixture;

[0049] (2) The mixed material is compression molded to obtain a degradable candle container.

[0050] The present invention modifies the filler and the modifying aid and then dries them, and then melts and mixes the obtained modified filler, polylactic acid, flame retardant synergist and environmentally friendly flame retardant to obtain a mixture. In the present invention, the filler is preferably treated with alkali before mixing; the alkali treatment preferably involves soaking the filler in an alkaline solution, then washing and filtering in sequence until it is neutral, and finally drying; the alkaline solution is preferably an aqueous NaOH solution, and the concentration is preferably 10-30wt%, more preferably 20wt%; the soaking time is preferably 12-36h, more preferably 24h; the washing agent is preferably deionized water; the drying temperature is preferably 60-120°C, more preferably 80-110°C, and the time is preferably 4-12h, more preferably 6-10h; the filler is preferably made of high-quality raw materials that are free of mildew, impurities and insects. In the present invention, when the modifying aid is 0 parts, the filler is directly dried, and then the dried filler, polylactic acid, flame retardant synergist and environmentally friendly flame retardant are melted and mixed to obtain a mixture.

[0051] In the present invention, the mixed modification is preferably: the modification aid is prepared into an aqueous solution of the modification aid, and then the filler is immersed in the aqueous solution of the modification aid, and then dried, crushed and sieved in sequence to obtain a modified filler; the particle size of the modified filler is preferably not more than 40 mesh, more preferably 40-60 mesh, and the water content is preferably not more than 6wt%, more preferably 0.1-3wt%; the crushing is preferably first putting the modified filler into a high-speed multifunctional crusher for crushing and then sieving, and then pouring the obtained modified filler with a particle size exceeding 40 mesh into a grinder for fine grinding and then sieving; the speed of the high-speed multifunctional crusher is preferably 3400-4000r / min, more preferably 3500-3800r / min; the drying device is preferably an electric constant temperature blast drying oven or a vacuum drying oven; the drying temperature is preferably 60-120°C, more preferably 80-100°C, and the time is preferably 4-12h, more preferably 6-10h.

[0052] In the present invention, the melt-kneading rate is preferably 50-150 r / min, more preferably 70-130 r / min; the melt-kneading temperature is preferably 40-80°C, more preferably 55-65°C, and the time is preferably 30-60 min, more preferably 40-50 min; the polylactic acid, flame retardant synergist and environmentally friendly flame retardant are preferably dried separately before melt-kneading; the drying temperature is preferably 60-100°C, more preferably 70-85°C, and the time is preferably 4-10 h, more preferably 6-8 h; the drying device is preferably a blast drying oven or a vacuum drying oven.

[0053] After obtaining the mixture, the present invention performs compression molding on the mixture to obtain a degradable candle container. In the present invention, the mold is preferably preheated before compression molding; the preheating temperature is preferably 120-200°C, more preferably 140-180°C, and the preheating time is preferably 5-20min, more preferably 8-15min. The compression molding pressure is 5-35MPa, more preferably 15-25MPa, and the time is preferably 2-10min, more preferably 3-5min; the compression molding device is preferably a pulp molding machine or a flat vulcanizer.

[0054] In the present invention, when the modification aid is a polylactic acid modification aid, the preparation method of the degradable candle container comprises the following steps:

[0055] (1) mixing polylactic acid and a modifying aid, performing a melt grafting reaction, and then crushing and drying to obtain modified polylactic acid;

[0056] (2) melt-mixing the modified polylactic acid, filler, flame retardant synergist and environmentally friendly flame retardant and then crushing them to obtain a mixture;

[0057] (3) The mixed material is compression molded to obtain a degradable candle container.

[0058] The present invention mixes polylactic acid and a modification aid for melt grafting reaction, then crushes and dries to obtain modified polylactic acid. In the present invention, the polylactic acid is preferably dried before mixing; the drying device is preferably an electric constant temperature drying oven; the drying temperature is preferably 40 to 120°C, more preferably 60 to 80°C, and the time is preferably 12 to 48 hours, more preferably 24 to 36 hours; the mixing is preferably mixing the modification aid and a good solvent to obtain a modified solution, and then mixing the modified solution with polylactic acid to remove the good solvent; the mass ratio of diisopropyl peroxide to polylactic acid is preferably 0.1 to 2:100, more preferably 1 to 2:100; the good solvent is preferably acetone; the method of removing the solvent is preferably to put the obtained mixed solution into a fume hood and wait for the solvent to completely evaporate; the temperature of the melt grafting reaction is preferably 150 to 210°C, more preferably 170 to 200°C, and the time is preferably 2 to 20 minutes, more preferably 5 to 15 minutes; the melt grafting reaction is carried out under melt mixing conditions; the melt mixing The refining rate is preferably 40-100r / min, more preferably 60-80r / min; the melt-mixing device is preferably a Haake torque rheometer; the melt grafting reaction is preferably cooled after completion; the cooling is preferably natural cooling; the final cooling temperature is preferably 20-40°C, more preferably 25-30°C; the pulverization rate is preferably 3400-4000r / min, more preferably 3500-3800r / min; the particle size of the product obtained by pulverization is preferably 10-60 mesh, more preferably 20-40 mesh; the pulverization device is preferably a high-speed pulverizer; the drying temperature is preferably 40-120°C, more preferably 60-80°C, the vacuum degree is preferably -0.04-0.1MPa, more preferably -0.06-0.1MPa, the time is preferably 4-12h, more preferably 6-10h; the drying device is preferably a vacuum drying oven.

[0059] After obtaining the modified polylactic acid, the present invention melt-mixes the modified polylactic acid, filler, flame retardant synergist and environmentally friendly flame retardant and then crushes them to obtain a mixture. In the present invention, the melt-mixing temperature is preferably 40 to 80° C., more preferably 55 to 65° C., the time is preferably 30 to 60 minutes, more preferably 40 to 50 minutes; the particle size of the product obtained by crushing is preferably 10 to 80 meshes, more preferably 40 to 60 meshes.

[0060] After obtaining the mixture, the present invention performs compression molding on the mixture to obtain a degradable candle container. In the present invention, the shape of the compression molding mold is preferably a regular shape or an irregular shape; the regular shape preferably includes a square, a circle, a bowl, a cup, a straight cylinder, a trapezoid or a five-pointed star shape; the compression molding pressure is preferably 5 to 35 MPa, and more preferably 15 to 25 MPa; the compression molding preferably includes hot pressing and cold pressing; the temperature of the hot pressing is preferably 120 to 210°C, and more preferably 140 to 180°C, and the time is preferably 2 to 10 min, and more preferably 3 to 5 min; the temperature of the cold pressing is preferably 10 to 40°C, and more preferably 25 to 35°C, and the time is preferably 5 to 20 min, and more preferably 8 to 15 min; the compression molding device is preferably a pulp molding machine or a flat vulcanizer; the present invention preferably first spreads the mixture in the mold, and then places the mold into a pulp molding machine or a flat vulcanizer for compression molding.

[0061] The present invention also provides the use of the degradable candle container described in the above scheme or the degradable candle container obtained by the preparation method described in the above scheme in candle accessories.

[0062] In the present invention, the application preferably includes: placing the candle in a candle container; the present invention has no special requirements for the placement method, and the placement method commonly used in the art can be used.

[0063] In order to further illustrate the present invention, the scheme of the present invention is described in detail below in conjunction with the accompanying drawings and embodiments, but they should not be understood as limiting the protection scope of the present invention.

[0064] Example 1

[0065] (1) preparing 100 L of a 20 wt % NaOH aqueous solution, and then soaking 70 kg of kenaf in the obtained NaOH aqueous solution. After 24 hours, the kenaf was taken out, rinsed with deionized water, filtered to neutralize the kenaf fiber, and dried for later use; preparing 100 L of a 10 wt % vinyl trimethoxysilane hexanol aqueous solution (the volume ratio of hexanol to water was 6:4), placing the alkali-treated kenaf in the vinyl trimethoxysilane hexanol aqueous solution, stirring at 200 r / min for 40 minutes, taking out the kenaf and drying it at 105° C. for 6 hours, crushing it to a length of 5 to 10 mm, and screening the kenaf with 50 mesh for later use;

[0066] (2) After placing each solid raw material in a blast drying oven at a constant temperature of 80° C. for 6 h, according to the formula requirements, 67 kg of poly-DL-lactic acid with a viscosity average molecular weight of 100,000, 12.5 kg of modified kenaf, 15.5 kg of flame retardant ammonium polyphosphate / polyethylene glycol / melamine (mass ratio of 3:1:1) and 5 kg of O-MMT (quaternary ammonium salt organic montmorillonite) were weighed and melt-mixed at a temperature of 50° C. and a rate of 110 r / min for 45 min;

[0067] (3) The mixed material is put into a bowl-shaped mold, the mold is preheated at 150° C. for 10 min, and the mold pressure is 5 MPa for 10 min to obtain a degradable candle container.

[0068] Example 2

[0069] (1) First, 2 L of 1 mol / L mixed metal ZnCl2 and AlCl3 salt solution (Zn 2+ :Al 3+ The method comprises the following steps: adding 1 mol / L NaOH solution to a 0.8 wt % sodium dodecylbenzene sulfonate solution to obtain an organic modified ZnAl-LDH (O-ZnAl-LDH) having a molar ratio of 2:1 to 5 L of a 0.8 wt % sodium dodecylbenzene sulfonate solution, and maintaining the reaction temperature at 50°C; during the synthesis process, adding 1 mol / L NaOH solution to maintain the pH value at 9±0.1, and then continuously stirring the resulting slurry at the same temperature for 0.5 h and aging it in a heater at 60°C for 18 h; filtering the final product and washing it with distilled water several times until the pH value of the supernatant is 7 to remove unreacted surfactant molecules (sodium dodecylbenzene sulfonate), and then drying the material in an oven at 70°C until a constant weight is reached to obtain an organic modified ZnAl-LDH (O-ZnAl-LDH);

[0070] (2) The solid raw materials were placed in a blast drying oven and dried at a constant temperature of 65°C for 10 hours. After drying, according to the formula requirements, 65 kg of poly (L-lactic acid) with a viscosity average molecular weight of 50,000, 15 kg of 40-mesh reed powder, 15 kg of flame retardant ammonium polyphosphate / polyethylene glycol / melamine cyanurate (mass ratio of 2:1:1) and 5 kg of O-ZnAl-LDH were weighed and melt-mixed at a temperature of 65°C and a rate of 85 r / min for 35 minutes;

[0071] (3) The mixed material is put into a cup-shaped mold and molded at 15 MPa for 3 minutes to obtain a degradable candle container.

[0072] Example 3

[0073] (1) Select high-quality rice husk fiber raw materials that are free of mildew, impurities, and insects, and grind them in a 3400 r / min high-speed multifunctional grinder to obtain plant fiber powders of different particle sizes. Then pour the filler with larger particle size that has been crushed in the grinder into a grinder and grind it finely for 30 minutes, pass it through a 50-mesh sieve, and then put it into an electric constant temperature blast drying oven to dry it at 80° C. for 12 hours;

[0074] (2) The solid raw materials were placed in a vacuum drying oven and dried at a constant temperature of 70°C for 4 h. Then, according to the formula requirements, 70 kg of poly (L-lactic acid) with a viscosity average molecular weight of 250,000, 13 kg of rice husk powder, 13 kg of flame retardant β-cyclodextrin / ammonium polyphosphate / polymelamine (mass ratio of 1:2:1) and 4 kg of O-MMT (ammonium phosphate organic montmorillonite) were weighed and melt-mixed at 70°C and 70 r / min for 30 min.

[0075] (3) The obtained mixture is evenly spread in a trapezoidal mold, and the mold is placed in a flat vulcanizer for molding at 35 MPa for 45 seconds to obtain a degradable candle container.

[0076] Example 4

[0077] (1) Place poly-DL-lactic acid with a viscosity average molecular weight of 300,000 in an electric constant temperature drying oven at 80° C. and dry for 24 h. Weigh 100 kg of the dried poly-lactic acid. Dissolve 2 kg of maleic anhydride (MAH) (2% of the mass of the poly-lactic acid) and 0.5 kg of dicumyl peroxide (DCP) (0.5% of the mass of the poly-lactic acid) in 800 L of acetone. Mix and stir with the poly-lactic acid pellets at 70 r / min until uniform. Place in a fume hood. After the solvent is completely evaporated, add a Haake torque rheometer at a speed of 60 r / min and melt-knead at 180° C. for 10 min to carry out a melt grafting reaction. After the blend is cooled, use a high-speed 3000 r / min pulverizer to crush and granulate into 20 meshes. Dry at 60° C. for 8 h to obtain maleic anhydride grafted poly-lactic acid.

[0078] (2) The solid raw materials were placed in a vacuum drying oven and dried at a constant temperature of 50°C for 4 h. Then, according to the formula requirements, 75 kg of modified PLA, 10 kg of 40-mesh sugarcane straw powder, 11 kg of flame retardant β-cyclodextrin / boric acid / polymelamine (1:3:1) and 4 kg of O-MMT (ammonium borate organic montmorillonite) were weighed and placed in a vacuum drying oven. The vacuum degree was -0.1 MPa and the temperature was constant at 60°C for 8 h, and the mixture was mixed evenly.

[0079] (3) The obtained mixture was put into a rheometer and melt-kneaded at 50°C for 1 hour. The melt-kneaded material was crushed into 20-mesh particles using a pulverizer at 3000 r / min, and then put into a mold and hot-pressed at 210°C and 15 MPa for 2 minutes using a flat plate vulcanizer. Finally, another flat plate vulcanizer without heating function was used to cold-press at 35°C and 5 MPa for 10 minutes to obtain a degradable candle container.

[0080] The degradable candle containers prepared in Examples 1 to 4 were tested for fire safety performance. The test was carried out in accordance with the safety requirements for plastic containers in ASTM F2417-17 "Standard Specification for Fire Safety of Candles", which is applicable to all plastic containers used for candles (currently there is no fire safety standard for degradable containers, so the standard for plastic containers is used for testing).

[0081] Safety requirements for plastic containers are as follows:

[0082] 1. The total burning time of ten plastic containers should be less than or equal to 300s;

[0083] 2. The burning time of a single plastic container shall not exceed 30s;

[0084] 3. During the test, no single plastic container shall burn completely.

[0085] Degradable candle containers that meet the above conditions are considered degradable flame-retardant containers and can be applied to all candles.

[0086] The specific detection method is as follows: take 10 degradable candle containers prepared in Examples 1 to 4, each cup is placed on its side for testing, and the flammability of 10 unused degradable candle containers is tested. The ignition source is a mixed butane lighter, and the flame length is adjusted to 29 to 41 mm. The top of the degradable candle container (12 o'clock position) is exposed to the ignition source twice, each time for 10 seconds, and the time the container continues to burn after the ignition source is removed is recorded. The burning time of the 10 test containers after each exposure of 10 seconds is added to obtain the total burning time (the sum of the 20 burning times is the total burning time). The results are shown in Table 1.

[0087] Table 1 Burning time of the degradable candle containers prepared in Examples 1 to 4

[0088]

[0089]

[0090] It can be seen from Table 1 that the degradable candle containers prepared in Examples 1 to 4 of the present invention all meet the fire safety requirements.

[0091] The degradable candle containers prepared in Examples 1 to 4 were subjected to a combustion test according to the UV94 combustion test method, and the results were all V0 grade.

[0092] The degradable candle containers prepared in Examples 1 to 4 were tested for their degradability under simulated natural conditions. The results showed that the degradation time of the degradable candle containers prepared in Examples 1 to 4 of the present invention was 2.5 to 3 years, indicating that the degradable candle containers provided by the present invention have good degradability.

[0093] It can be seen from the above embodiments that the degradable candle container provided by the present invention not only has good flame retardant properties, reduces the use of flame retardants, but also has excellent biodegradability, good processing performance and mechanical properties, a wide source of raw materials, low cost, and can better solve the problem of two-phase dispersion. The degradable candle container of the present invention is applied to the field of candle accessories to ensure the safety of candle burning and prevent the candle container from being ignited.

[0094] Although the above embodiment describes the present invention in detail, it is only a part of the embodiments of the present invention, not all of the embodiments. Other embodiments can be obtained based on this embodiment without creativity, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A degradable candle container, characterized in that: Prepared from the following raw materials in parts by weight: 60-100 parts of polylactic acid, 5-20 parts of filler, 5-20 parts of environmentally friendly flame retardant, 1-6 parts of flame retardant synergist and 0-7 parts of modification additive; The modification aid includes one or both of a polylactic acid modification aid and a filler modification aid; The polylactic acid modification aid includes one or both of maleic anhydride and dicumyl peroxide; the filler modification aid includes one or both of silane coupling agent and alkali metal hydroxide solution; The filler comprises one or more of hemp, fiber and agricultural waste.

2. The degradable candle container according to claim 1, characterized in that: The environmentally friendly flame retardant includes an acid source, a carbon source and a gas source; the acid source includes one or more of ammonium polyphosphate, ammonium salt and inorganic acid; the carbon source includes one or more of starch, dextrin, cellulose, polyol and alcohol; and the gas source is amine.

3. The degradable candle container according to any one of claim 2, characterized in that: The mass ratio of the acid source to the carbon source in the environmentally friendly flame retardant is 1-5:1-3, and the mass ratio of the carbon source to the gas source is 1-3:1-3.

4. The degradable candle container according to claim 1, characterized in that: The polylactic acid includes one or more of poly DL-lactic acid and poly L-lactic acid; the viscosity average molecular weight of the polylactic acid is 1000-300000.

5. The degradable candle container according to claim 1, characterized in that: The particle size of the filler is 10 to 100 meshes.

6. The degradable candle container according to claim 1, characterized in that: The flame retardant synergist includes one or more of layered double hydroxide, modified montmorillonite and expandable graphite.

7. The degradable candle container according to claim 1, characterized in that: The hemp includes one or more of kenaf, hemp, flax, jute and sisal; the fiber is one or two of bamboo fiber and reed; the agricultural waste includes one or more of wheat straw powder, sugarcane straw powder, rice husk powder and rice straw powder.

8. The method for preparing the degradable candle container according to any one of claims 1 to 7, when the modification aid is a filler modification aid, the method comprises the following steps: (1) mixing and modifying a filler and a modifying aid, and then drying the modified filler, polylactic acid, a flame retardant synergist, and an environmentally friendly flame retardant to obtain a mixture; (2) The mixed material is compression molded to obtain a degradable candle container.

9. The method for preparing the degradable candle container according to any one of claims 1 to 7, when the modification aid is a polylactic acid modification aid, the method comprises the following steps: (1) mixing polylactic acid and a modifying aid, performing a melt grafting reaction, and then crushing and drying to obtain modified polylactic acid; (2) melt-mixing the modified polylactic acid, filler, flame retardant synergist and environmentally friendly flame retardant and then crushing them to obtain a mixture; (3) The mixed material is compression molded to obtain a degradable candle container.

10. Use of the degradable candle container according to any one of claims 1 to 7 or the degradable candle container obtained by the preparation method according to any one of claims 8 to 9 in candle accessories.

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