A heat-resistant cellulose acetate material, its preparation method and application

Abstract

The present invention discloses a heat-resistant cellulose acetate material and its application, belonging to the technical field of cellulose acetate materials. The raw materials of the heat-resistant cellulose acetate material by mass percentage include: 65%-75% of diacetate cellulose grafted with poly(p-dioxanone), 1%-2% of a surfactant, 23%-33% of an epoxyalkyl ester composition of the compound represented by Formula 1, and 1%-2% of an antioxidant. The heat-resistant cellulose acetate material can weaken the action of hydrogen bonds between the molecular chains of diacetate cellulose, improve the fluidity of diacetate cellulose during processing, avoid carbonization of diacetate cellulose due to insufficient fluidity during processing, reduce the glass transition temperature (Tg) of diacetate cellulose, and improve the thermal stability of diacetate cellulose during processing.

Description

Technical Field

[0001] The present invention relates to the technical field of cellulose acetate materials, and particularly relates to a heat-resistant cellulose acetate material, a preparation method thereof, and an application thereof. Background Art

[0002] Cellulose acetate is an acetate ester of cellulose, a chemically modified natural polymer obtained by esterifying the hydroxyl groups in the cellulose molecule with acetic acid. Cellulose acetate is mainly divided into two categories: diacetate fiber and triacetate fiber, and its properties depend on the degree of acetylation, that is, the average number of hydroxyl groups in the glucose unit of cellulose replaced by acetyl groups. Diacetate cellulose is formed after partial hydrolysis of cellulose acetate, and its esterification degree is lower than that of triacetate cellulose. Therefore, its heat resistance is inferior to that of triacetate cellulose, its dyeing performance is better than that of triacetate cellulose, and its moisture absorption rate is higher than that of triacetate cellulose. Triacetate cellulose is not hydrolyzed and has a higher degree of esterification. Therefore, it has strong light and heat resistance, poor dyeing performance, and a lower moisture absorption rate (also called regain rate).

[0003] When the degree of substitution of cellulose is less than 2.0, the molecular fluidity during melting will decrease, the biodegradability will become poor, and the cellulose acetate will carbonize at high temperatures during melting. When processing diacetate cellulose, due to the very high glass transition temperature (Tg) of diacetate cellulose, its melting processing temperature even exceeds the degradation temperature (Td). Because the glass transition temperature (Tg) is close to the decomposition temperature, the processing temperature window is very narrow, resulting in limited processing ability. Diacetate cellulose decomposes before melt flow. Therefore, it is very important to lower the glass transition temperature (Tg) of diacetate cellulose and improve the fluidity of diacetate cellulose. This material needs to be plasticized to improve its thermal properties and tensile properties. In addition, the molecular structure of diacetate cellulose contains a large number of highly polar hydroxyl groups, and the hydrogen bonds between the molecular chains of diacetate cellulose are strong, resulting in poor fluidity in the molten state. Under high-temperature processing, it is prone to carbonization, easy to decompose, and has poor heat resistance. In order to facilitate the improvement of the fluidity of diacetate cellulose in the molten state, a certain amount of plasticizer is usually added during the processing of diacetate cellulose. In different applications, the addition amount of the plasticizer is usually between 15% and 35%. Commonly used plasticizers include: fatty acid esters, phthalates, citrate esters, etc. The type and amount of the plasticizer also have a certain impact on the heat resistance of diacetate cellulose. The heat resistance of the plasticizer determines its stability at high temperatures. Once the plasticizer decomposes at high temperatures, the heat resistance of diacetate cellulose will also become poor. The degradation of the plasticizer causes pores to form on the surface of the mixture of the plasticizer and diacetate cellulose, thereby accelerating the degradation process of diacetate cellulose. The reason is that a large number of holes are generated on the surface of the mixture, providing a larger specific surface area for diacetate cellulose or providing an acidic environment for the rapid degradation of diacetate cellulose, thereby promoting its degradation. Summary of the Invention

[0004] In order to overcome the deficiencies of the prior art, one of the objectives of the present invention is to provide a heat-resistant cellulose acetate material, which can weaken the action of hydrogen bonds between the molecular chains of cellulose diacetate, improve the fluidity of cellulose diacetate during the processing, avoid carbonization of cellulose diacetate due to insufficient fluidity during the processing, reduce the glass transition temperature (Tg) of cellulose diacetate, and improve the thermal stability of cellulose diacetate during the processing.

[0005] Another objective of the present invention is to provide a preparation method of the heat-resistant cellulose acetate material, the method has simple steps and can industrially produce the heat-resistant cellulose acetate material.

[0006] The third objective of the present invention is to provide the application of the heat-resistant cellulose acetate material.

[0007] One of the objectives of the present invention is achieved by the following technical solutions:

[0008] A heat-resistant cellulose acetate material, the raw materials by mass percentage include: 65%-75% of cellulose diacetate grafted poly(p-dioxanone), 1%-2% of surfactant, 23%-33% of the epoxyalkyl ester composition of the compound represented by formula 1, 1%-2% of antioxidant;

[0009] Formula 1

[0010]

[0011] In formula 1, R1 is an alkyl group with 8 to 20 carbon atoms containing one to three epoxy groups, and R2 is an alkyl group with 4, 5 or 8 to 10 carbon atoms.

[0012] Further, the raw materials by mass percentage include: 70% of cellulose diacetate grafted poly(p-dioxanone), 1% of surfactant, 28% of the epoxyalkyl ester composition of the compound represented by formula 1, 1% of antioxidant.

[0013] Further, the antioxidant is tetrakis[methylene(3,5-di-tert-butyl-4-hydroxyhydrocinnamate)]methane or tris(2,4-di-tert-butylphenyl) phosphite.

[0014] Further, R2 in formula 1 is selected from butyl, pentyl, 2-ethylhexyl, isononyl and 2-propylheptyl.

[0015] Further, the surfactant is one of fatty acid polyoxyethylene ester, pentaerythritol, sodium oleoyloxyethyl sulfonate, cetyltrimethylammonium chloride, coconut oil amide propyl betaine.

[0016] Further, the preparation method of the cellulose diacetate grafted poly(p-dioxanone) comprises the following steps:

[0017] S1. Add 2.0 g of cellulose diacetate into a strictly dried flask, and wash it three times with dry nitrogen;

[0018] S2. Then, add 6.69 g of p-dioxanone (PDO) monomer into the strictly dried flask through a syringe, and place the strictly dried flask in a preheated oil bath at 120 °C for 30 min to obtain a clear homogeneous solution system;

[0019] S3. Next, inject 0.84 mL of stannous octanoate (Sn(Oct) 2 ) solution under nitrogen condition at 140 °C, and react at a reaction temperature of 140 °C for 2 h;

[0020] S4. After quickly cooling to 0 °C, dissolve the crude product in chloroform and precipitate with anhydrous methanol; then, extract the sediment with toluene and acetone for 48 h respectively for purification; dry it to constant weight in a vacuum oven at 60 °C to obtain the cellulose diacetate grafted poly(p-dioxanone).

[0021] The second object of the present invention is achieved by adopting the following technical solution:

[0022] A manufacturing method of a heat-resistant cellulose acetate material, comprising the following steps:

[0023] S1. At room temperature, mix the cellulose diacetate grafted poly(p-dioxanone) and the epoxyalkyl ester composition of the compound represented by formula 1 in a high-speed mechanical stirrer according to the formula amount for 2 min, and then dry the mixture in a vacuum oven at 70 °C to 90 °C for 20 - 30 h to obtain a plasticized mixture;

[0024] S2. Add the plasticized mixture into a twin-screw extruder, and then add an antioxidant and a surfactant into the twin-screw extruder. After melt extrusion, slice the cellulose diacetate grafted poly(p-dioxanone) to produce particles to obtain the heat-resistant cellulose acetate material.

[0025] Further, in step S1, the mixture is dried in a vacuum oven at 70 °C for 24 h.

[0026] The third object of the present invention is to provide an application of a heat-resistant cellulose acetate material.

[0027] Further, the heat-resistant cellulose acetate material is used for manufacturing spectacle frames and high-grade tool handles.

[0028] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0029] A heat-resistant cellulose acetate material provided by the present invention, with an epoxyalkyl ester composition of the compound represented by Formula 1 as a plasticizer, has good thermal stability, can improve the plasticizing efficiency for diacetate cellulose, reduce the glass transition temperature (Tg) of diacetate cellulose, and prevent diacetate cellulose from carbonizing during processing due to insufficient fluidity; in diacetate cellulose grafted with poly(p-dioxanone), due to the presence of ether bonds and methylene groups in the molecular structure of the poly(p-dioxanone) side chains, it has better flexibility, and the diacetate cellulose grafted with poly(p-dioxanone) has a lower crystallinity, which can weaken the hydrogen bond interaction between the molecular chains of diacetate cellulose, reduce the rigidity of the molecular chains of diacetate cellulose, and together reduce the glass transition temperature (Tg) of diacetate cellulose, contributing to improving the fluidity of diacetate cellulose during processing, making it easier to form during processing, and preventing diacetate cellulose from carbonizing during processing due to insufficient fluidity; the surfactant can reduce the surface tension when diacetate cellulose melts, reduce the intermolecular interaction force, make diacetate cellulose flow more easily, and prevent diacetate cellulose from carbonizing during processing due to insufficient fluidity; the antioxidant can prevent the decomposition of diacetate cellulose caused by high temperature during the melting and heating process in a twin-screw extruder. Specific Embodiments

[0030] Next, in combination with specific embodiments, the present invention will be further described. It should be noted that, on the premise of no conflict, the following described embodiments or technical features can be arbitrarily combined to form new embodiments.

[0031] Diacetate cellulose was purchased from Sichuan Push Cellulose Acetate Co., Ltd., Changning, China; the acetylation content was about 40%, and the average degree of acetyl substitution (DS) of diacetate cellulose was determined to be 2.41 by 1H-NMR; the average particle size (d50) of the powder was 250 μm, and the specific gravity was 1.20 - 1.32 g·cm -3 ; the glass transition temperature was about 198 °C, and the melting temperature was between 230 - 250 °C; diacetate cellulose was used after vacuum drying at 70 °C for more than 72 h;

[0032] p-Dioxanone (PDO) was dried on CaH 2 for 48 h and immediately distilled under reduced pressure twice before use. Stannous octoate (Sn(Oct) 2 ), chloroform, anhydrous methanol, toluene, and acetone were purchased from Sinopharm Chemical Reagent Co., Ltd.;

[0033] The antioxidants tetrakis[methylene(3,5-di-tert-butyl-4-hydroxyhydrocinnamate)]methane and tris(2,4-di-tert-butylphenyl) phosphite were purchased from Hubei Xinrunde Chemical Co., Ltd.;

[0034] The TA differential scanning calorimeter DSC Q200 was purchased from Shenzhen Xinyichuang Technology Co., Ltd.;

[0035] The thermogravimetric analyzer Netzsch TG 209F1 was purchased from Hangzhou Hanze Instruments Co., Ltd.

[0036] The molecular chain of cellulose diacetate is rigid for the following reasons: First, its molecules are polar and the intermolecular forces are very strong; second, the six-membered pyran ring structure in cellulose diacetate makes internal rotation difficult; finally, hydrogen bonds can be formed both intramolecularly and intermolecularly, especially intramolecular hydrogen bonds, which cause the glycosidic bond not to rotate, thus greatly increasing its rigidity.

[0037] Example 1

[0038] This example provides a heat-resistant cellulose acetate material. The raw materials by mass percentage include: 70% of cellulose diacetate grafted poly(p-dioxanone), 1% of the surfactant fatty acid polyoxyethylene ester, 28% of the epoxidized alkyl ester composition of the compound represented by Formula 1, and 1% of the antioxidant.

[0039] Formula 1

[0040]

[0041] Among them, the antioxidant can prevent the decomposition of cellulose diacetate caused by high temperature during the melting and heating process in the twin-screw extruder.

[0042] In this example, the antioxidant is tetra[methylenebis(3,5-di-tert-butyl-4-hydroxyhydrocinnamate)]methane, which is antioxidant 1010.

[0043] R1 in Formula 1 is an isononyl group with 8 carbon atoms containing one epoxy group; R2 is selected from butyl.

[0044] In this example, the preparation method of cellulose diacetate grafted poly(p-dioxanone) includes the following steps:

[0045] S1. Add 2.0 g of cellulose diacetate to a strictly dried flask and wash it three times with dry nitrogen;

[0046] S2. Then, through a syringe, add 6.69 g of p-dioxanone (PDO) monomer to the strictly dried flask, and place the strictly dried flask in a preheated oil bath at 120 °C for 30 min to obtain a clear homogeneous solution system;

[0047] S3. Then inject 0.84 mL of stannous octanoate Sn(Oct) 2 solution under nitrogen conditions at 140 °C and react at a reaction temperature of 140 °C for 2 h;

[0048] S4. After rapidly cooling to 0 °C, the crude product was dissolved in chloroform and precipitated with anhydrous methanol; then the sediment was extracted with toluene and acetone for 48 h respectively for purification; and dried to constant weight under vacuum at 60 °C to obtain cellulose diacetate grafted poly(p-dioxanone).

[0049] As an important aliphatic polyester, poly(p-dioxanone) (PPDO) was subjected to a graft copolymerization reaction of p-dioxanone (PDO) and cellulose diacetate by means of ring-opening polymerization in the presence of stannous octoate (Sn(Oct) 2 ).

[0050] This example provides a method for preparing a heat-resistant cellulose acetate material, comprising the following steps:

[0051] S1. At room temperature, cellulose diacetate grafted poly(p-dioxanone) and the epoxyalkyl ester composition of the compound represented by Formula 1 were mixed in a high-speed mechanical stirrer for 2 min according to the formula amount, and then the mixture was dried in a vacuum oven at 70 °C for 24 h to obtain a plasticized mixture;

[0052] S2. The plasticized mixture was added to a twin-screw extruder, and then an antioxidant and a surfactant were added to the twin-screw extruder. After melt extrusion, the cellulose diacetate grafted poly(p-dioxanone) was sliced into pellets to obtain a heat-resistant cellulose acetate material.

[0053] The crystallinity of cellulose diacetate (Cellulose Diacetate, CDA) is affected by the degree of acetylation and the processing process. According to research, cellulose forms cellulose triacetate (Cellulose Triacetate, CTA) after acetylation, and its crystal form changes and the crystallinity decreases. Further, the cellulose diacetate obtained by hydrolysis of cellulose triacetate has an obvious advantage in the amorphous region, which means that the crystallinity of cellulose diacetate is further reduced.

[0054] Example 2

[0055] This example provides a heat-resistant cellulose acetate material, and the raw materials by mass percentage include: 75% of cellulose diacetate grafted poly(p-dioxanone), 1% of the surfactant pentaerythritol, 23% of the epoxyalkyl ester composition of the compound represented by Formula 1, and 1% of the antioxidant;

[0056] Formula 1

[0057]

[0058] Among them, antioxidants can prevent the decomposition of cellulose diacetate caused by high temperature during the melting and heating process in a twin-screw extruder.

[0059] In this embodiment, the antioxidant is tris(2,4-di-tert-butylphenyl) phosphite, which is antioxidant 168.

[0060] R1 in Formula 1 is an alkyl group with 20 carbon atoms containing two epoxy groups; R2 is selected from pentyl.

[0061] The preparation method of cellulose diacetate grafted with poly(p-dioxanone) in this embodiment includes the following steps:

[0062] S1. Add 2.0 g of cellulose diacetate into a strictly dried flask and wash it three times with dry nitrogen.

[0063] S2. Then, through a syringe, add 6.69 g of p-dioxanone (PDO) monomer into the strictly dried flask, and place the strictly dried flask in a preheated oil bath at 120 °C for 30 min to obtain a clear homogeneous solution system.

[0064] S3. Then inject 0.84 mL of stannous octanoate (Sn(Oct) 2 ) solution under nitrogen condition at 140 °C, and react at the reaction temperature of 140 °C for 2 h.

[0065] S4. After quickly cooling to 0 °C, dissolve the crude product in chloroform and precipitate it with anhydrous methanol; then extract the sediment with toluene and acetone for 48 h respectively for purification; dry it to constant weight in a vacuum at 60 °C to obtain cellulose diacetate grafted with poly(p-dioxanone).

[0066] This embodiment provides a preparation method of a heat-resistant cellulose acetate material, including the following steps:

[0067] S1. At room temperature, mix the cellulose diacetate grafted with poly(p-dioxanone) and the epoxyalkyl ester composition of the compound represented by Formula 1 in a high-speed mechanical stirrer according to the formula amount for 2 min, and then dry the mixture in a vacuum oven at 85 °C for 20 h to obtain a plasticized mixture.

[0068] S2. Add the plasticized mixture into a twin-screw extruder, then add an antioxidant and a surfactant into the twin-screw extruder. After melt extrusion, slice the cellulose diacetate grafted with poly(p-dioxanone) to produce it in the form of particles, and obtain a heat-resistant cellulose acetate material.

[0069] Example 3

[0070] This embodiment provides a heat-resistant cellulose acetate material. The raw materials by mass percentage include: 65% of diacetate cellulose grafted with poly(p-dioxanone), 2% of surfactant sodium oleoyloxyethyl sulfonate, 31% of an epoxyalkyl ester composition of the compound represented by Formula 1, and 2% of an antioxidant;

[0071] Formula 1

[0072]

[0073] Among them, the antioxidant can prevent the decomposition of diacetate cellulose caused by high temperature during the melting and heating process in a twin-screw extruder.

[0074] In this embodiment, the antioxidant is tetra[methylene(3,5-di-tert-butyl-4-hydroxyhydrocinnamate)]methane.

[0075] In Formula 1, R1 is an alkyl group with 15 carbon atoms containing three epoxy groups; R2 is selected from 2-ethylhexyl.

[0076] The preparation method of diacetate cellulose grafted with poly(p-dioxanone) in this embodiment includes the following steps:

[0077] S1. Add 2.0 g of diacetate cellulose into a strictly dried flask and wash it three times with dry nitrogen;

[0078] S2. Then, add 6.69 g of p-dioxanone (PDO) monomer into the strictly dried flask through a syringe, and place the strictly dried flask in a preheated oil bath at 120 °C for 30 min to obtain a clear homogeneous solution system;

[0079] S3. Then, inject 0.84 mL of stannous octanoate (Sn(Oct) 2 ) solution under nitrogen condition at 140 °C, and react at the reaction temperature of 140 °C for 2 h;

[0080] S4. After quickly cooling to 0 °C, dissolve the crude product in chloroform and precipitate it with anhydrous methanol; then extract the sediment with toluene and acetone for 48 h respectively for purification; dry it to constant weight in a vacuum oven at 60 °C to obtain diacetate cellulose grafted with poly(p-dioxanone).

[0081] This embodiment provides a preparation method of a heat-resistant cellulose acetate material, including the following steps:

[0082] S1. At room temperature, mix diacetate cellulose grafted with poly(p-dioxanone) and the epoxyalkyl ester composition of the compound represented by Formula 1 in a high-speed mechanical stirrer for 2 min according to the formula amount, and then dry the mixture in a vacuum oven at 90 °C for 30 h to obtain a plasticized mixture;

[0083] S2. Add the plasticized mixture to a twin-screw extruder, then add an antioxidant and a surfactant to the twin-screw extruder. After melt extrusion, graft poly(p-dioxanone) onto cellulose diacetate to produce slices in the form of particles, obtaining a heat-resistant cellulose acetate material.

[0084] Example 4

[0085] This example provides a heat-resistant cellulose acetate material. The raw materials by mass percentage include: 64% of cellulose diacetate grafted with poly(p-dioxanone), 1% of the surfactant cetyltrimethylammonium chloride, 33% of the epoxyalkyl ester composition of the compound represented by Formula 1, and 2% of an antioxidant.

[0086] Formula 1

[0087]

[0088] Among them, the antioxidant can prevent the decomposition of cellulose diacetate caused by high temperature during the melt heating process in the twin-screw extruder.

[0089] In this example, the antioxidant is tetra[methylene(3,5-di-tert-butyl-4-hydroxyhydrocinnamate)]methane.

[0090] R1 in Formula 1 is an alkyl group with 10 carbon atoms containing one epoxy group; R2 is selected from isononyl.

[0091] The preparation method of cellulose diacetate grafted with poly(p-dioxanone) in this example includes the following steps:

[0092] S1. Add 2.0 g of cellulose diacetate to a strictly dried flask and wash it three times with dry nitrogen.

[0093] S2. Then, add 6.69 g of p-dioxanone (PDO) monomer to the strictly dried flask through a syringe, and place the strictly dried flask in a preheated oil bath at 120 °C for 30 min to obtain a clear homogeneous solution system.

[0094] S3. Then, inject 0.84 mL of stannous octanoate (Sn(Oct) 2 ) solution under nitrogen at 140 °C, and react at a reaction temperature of 140 °C for 2 h.

[0095] S4. After quickly cooling to 0 °C, dissolve the crude product in chloroform and precipitate it with anhydrous methanol; then, extract the sediment with toluene and acetone for 48 h respectively for purification; dry it to constant weight in vacuo at 60 °C to obtain cellulose diacetate grafted with poly(p-dioxanone).

[0096] This embodiment provides a method for preparing a heat-resistant cellulose acetate material, comprising the following steps:

[0097] S1. At room temperature, according to the formula amount, graft poly(p-dioxanone) onto cellulose diacetate and an epoxidized alkyl ester composition of the compound represented by Formula 1 are mixed in a high-speed mechanical stirrer for 2 min, and then the mixture is dried in a vacuum oven at 70 °C for 24 h to obtain a plasticized mixture;

[0098] S2. The plasticized mixture is added to a twin-screw extruder, and then an antioxidant and a surfactant are added to the twin-screw extruder. After melt extrusion, the graft poly(p-dioxanone) onto cellulose diacetate is sliced into particles to obtain a heat-resistant cellulose acetate material.

[0099] Further, in step S1, the mixture is dried in a vacuum oven at 70 °C for 24 h.

[0100] Example 5

[0101] This embodiment provides a heat-resistant cellulose acetate material. The raw materials by mass percentage include: 64% of graft poly(p-dioxanone) onto cellulose diacetate, 2% of surfactant cocamidopropyl betaine, 33% of an epoxidized alkyl ester composition of the compound represented by Formula 1, and 1% of an antioxidant;

[0102] Formula 1

[0103]

[0104] Among them, the antioxidant can prevent the decomposition of cellulose diacetate caused by high temperature during the melt heating process in the twin-screw extruder.

[0105] In this embodiment, the antioxidant is tetrakis[methylene(3,5-di-tert-butyl-4-hydroxyhydrocinnamate)]methane.

[0106] R1 in Formula 1 is an alkyl group with 18 carbon atoms containing two epoxy groups; R2 is selected from 2-propylheptyl.

[0107] The preparation method of the graft poly(p-dioxanone) onto cellulose diacetate in this embodiment includes the following steps:

[0108] S1. Add 2.0 g of cellulose diacetate to a strictly dried flask and wash it three times with dry nitrogen;

[0109] S2. Then, through a syringe, add 6.69 g of p-dioxanone (PDO) monomer to the strictly dried flask, and place the strictly dried flask in a preheated oil bath at 120 °C for 30 min to obtain a clear homogeneous solution system;

[0110] S3. Next, 0.84 mL of stannous octoate (Sn(Oct) 2 ) solution was injected under nitrogen at 140 °C, and the reaction was carried out at a reaction temperature of 140 °C for 2 h;

[0111] S4. After rapidly cooling to 0 °C, the crude product was dissolved in chloroform and precipitated with anhydrous methanol; then the sediment was extracted with toluene and acetone for 48 h respectively for purification; it was dried in vacuo at 60 °C to constant weight to obtain cellulose diacetate grafted poly(p-dioxanone).

[0112] This example provides a preparation method of a heat-resistant cellulose acetate material, including the following steps:

[0113] S1. At room temperature, cellulose diacetate grafted poly(p-dioxanone) and the epoxyalkyl ester composition of the compound represented by Formula 1 were mixed in a high-speed mechanical stirrer for 2 min according to the formula amount, and then the mixture was dried in a vacuum oven at 70 °C for 24 h to obtain a plasticized mixture;

[0114] S2. The plasticized mixture was added to a twin-screw extruder, and then an antioxidant and a surfactant were added to the twin-screw extruder. After melt extrusion, the cellulose diacetate grafted poly(p-dioxanone) was sliced to produce a granular form to obtain a heat-resistant cellulose acetate material.

[0115] Further, in step S1, the mixture was dried in a vacuum oven at 70 °C for 24 h.

[0116] Comparative Example 1

[0117] The difference from Example 1 is that Comparative Example 1 provides cellulose diacetate.

[0118] Comparative Example 2

[0119] The difference from Example 1 is that a heat-resistant cellulose acetate material provided by Comparative Example 1 includes, by mass percentage: 70% of cellulose diacetate, 1% of the surfactant fatty acid polyoxyethylene ester, 28% of the epoxyalkyl ester composition of the compound represented by Formula 1, and 1% of antioxidant 1010.

[0120] Comparative Example 3

[0121] The difference from Example 1 is that a heat-resistant cellulose acetate material provided by Comparative Example 1 includes, by mass percentage: 98% of cellulose diacetate grafted poly(p-dioxanone), 1% of the surfactant fatty acid polyoxyethylene ester, and 1% of antioxidant 1010.

[0122] Comparative Example 4

[0123] The difference from Example 1 is that a heat-resistant cellulose acetate material provided in Comparative Example 1 includes, by mass percentage, 1% of surfactant fatty acid polyoxyethylene ester, 98% of an epoxyalkyl ester composition of the compound represented by Formula 1, and 1% of antioxidant 1010.

[0124] Comparative Example 5

[0125] The difference from Example 1 is that a heat-resistant cellulose acetate material provided in Comparative Example 1 includes, by mass percentage, 70% of diacetate cellulose grafted poly(p-dioxanone), 28% of an epoxyalkyl ester composition of the compound represented by Formula 1, and 2% of antioxidant 1010.

[0126] Experimental Example 1

[0127] Determination of glass transition temperature

[0128] Differential scanning calorimetry (DSC) was carried out using a TA instrument DSC Q200. Under a nitrogen atmosphere, measurements were performed in a sealed aluminum pan at a scanning rate of 20 °C / min and calibrated with an indium standard metal. The samples of Examples 1-5 and Comparative Examples 1-5 were first cooled to -50 °C, heated to 140 °C, held at 140 °C for 5 minutes to eliminate the influence of thermal history, and then quenched to -50 °C during the first heating scan. The samples of Examples 1-5 and Comparative Examples 1-5 were heated from -50 °C to 190 °C again for the second heating scan, and the glass transition temperature Tg and melting temperature Tm were determined through the thermogram. The samples of Examples 1-5 and Comparative Examples 1-5 required at least 3 measurements on average, and the measurement results are shown in Table 1.

[0129] Determination of thermal stability

[0130] The thermal stability of Examples 1-5 and Comparative Examples 1-5 was studied using a thermogravimetric analyzer Netzsch TG 209F1. 5-10 mg of the sample was placed on a platinum pan and heated under a nitrogen atmosphere, and the scanning temperature range was set from 25 °C to 700 °C with a heating rate of 10 °C / min. The results of thermogravimetric (DTG) analysis were obtained by measuring the percentage of mass loss of the sample at the measurement temperature. The samples of Examples 1-5 and Comparative Examples 1-5 required at least 3 measurements on average, and the measurement results are shown in Table 1.

[0131] Table 1

[0132]

[0133]

[0134] Note: Ti is the initial degradation temperature of the sample; T20% is the temperature at which the sample loses 20% of its weight; T50% is the temperature at which the sample loses 50% of its weight

[0135] As can be seen from Table 1, the glass transition temperatures Tg of Examples 1-5 are significantly lower than those of Comparative Examples 1-5, and the Ti values, T20% values, and T50% values are significantly higher than those of Comparative Examples 1-5, indicating that Examples 1-5 have good thermal stability and heat resistance; the glass transition temperatures Tg of Comparative Examples 2-4 are significantly higher than those of Examples 1-5, and the Ti values, T20% values, and T50% values are significantly lower than those of Examples 1-5, indicating that on the one hand, grafting poly(p-dioxanone) onto cellulose diacetate can weaken the hydrogen bonding between the molecular chains of cellulose diacetate, reduce the rigidity of the molecular chains of cellulose diacetate, and improve the fluidity of cellulose diacetate during processing, making it easier for cellulose diacetate to be molded during processing and avoiding carbonization of cellulose diacetate due to insufficient fluidity during processing. On the other hand, the combination of cellulose diacetate grafted with poly(p-dioxanone) and the epoxyalkyl ester composition coordinately reduces the glass transition temperature Tg of cellulose diacetate and improves the fluidity of cellulose diacetate during processing, making it easier for cellulose diacetate to be molded during processing and avoiding carbonization of cellulose diacetate due to insufficient fluidity during processing; the glass transition temperature Tg of Comparative Example 5 is higher than that of Example 1, and the Ti value, T20% value, and T50% value are lower than those of Example 1, indicating that the surfactant can reduce the surface tension of cellulose diacetate during melting, reduce the intermolecular interaction force, make cellulose diacetate flow more easily, and avoid carbonization of cellulose diacetate due to insufficient fluidity during processing.

[0136] The above embodiments are only the preferred embodiments of the present invention and cannot be used to limit the scope of protection of the present invention. Any non-substantial changes and substitutions made by those skilled in the art based on the present invention fall within the scope of protection required by the present invention.

Claims

1. A heat-resistant cellulose acetate material, characterized in that: The raw materials include, by mass percentage, 65%-75% of cellulose diacetate grafted polydioxanone, 1%-2% of a surfactant, 23%-33% of an epoxidized alkyl ester composition of a compound represented by formula 1, and 1%-2% of an antioxidant; Formula 1 In Formula 1, R1 is an alkyl group having 8 to 20 carbon atoms containing one to three epoxy groups, and R2 is an alkyl group having 4, 5, or 8 to 10 carbon atoms.

2. A thermal cellulose acetate material according to claim 1, characterized in that: The raw materials, calculated by mass percentage, include: 70% of cellulose diacetate grafted polydioxanone, 1% of a surfactant, 28% of an epoxidized alkyl ester composition of a compound represented by Formula 1, and 1% of an antioxidant.

3. A thermal cellulose acetate material according to claim 1, characterized in that: The antioxidant is tetrakis[methylene(3,5-di-tert-butyl-4-hydroxyhydrocinnamate)]methane or tris(2,4-di-tert-butylphenyl)phosphite.

4. The thermal cellulose acetate material according to claim 1, characterized in that: R2 in Formula 1 is selected from the group consisting of butyl, pentyl, 2-ethylhexyl, isononyl and 2-propylheptyl.

5. The thermal cellulose acetate material according to claim 1, characterized in that: The surfactant is one of polyoxyethylene fatty acid ester, pentaerythritol, sodium oleyloxyethanesulfonate, cetyltrimethylammonium chloride and cocamidopropyl betaine.

6. The thermal cellulose acetate material according to claim 1, characterized in that: The preparation method of cellulose diacetate grafted polydioxanone comprises the following steps: S1. Add 2.0 g of cellulose diacetate into a strictly dried flask and purge it with dry nitrogen three times; S2, then add 6.69 g of p-dioxanone monomer into the strictly dried flask through a syringe, and place the strictly dried flask in a preheated oil bath at a temperature of 120° C. for 30 min to obtain a clear homogeneous solution system; S3, then inject 0.84 mL of stannous octoate solution under nitrogen conditions at 140° C., and react at a reaction temperature of 140° C. for 2 h; S4. After rapidly cooling to 0°C, the crude product is dissolved in chloroform and precipitated with anhydrous methanol; the precipitate is then extracted with toluene and acetone for 48 hours for purification; and vacuum dried at 60°C to constant weight to obtain the cellulose diacetate grafted polydioxanone.

7. A method for preparing a heat-resistant cellulose acetate material according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1. At room temperature, cellulose diacetate grafted polydioxanone and an epoxidized alkyl ester composition of a compound represented by Formula 1 are mixed in a high-speed mechanical stirrer for 2 minutes according to the formula amount, and then the mixture is dried in a vacuum oven at 70° C. to 90° C. for 20 to 30 hours to obtain a plasticized mixture; S2. Add the plasticized mixture into a twin-screw extruder, then add an antioxidant and a surfactant into the twin-screw extruder, and after melt extrusion, slice the cellulose diacetate grafted with polydioxanone to produce particles to obtain the heat-resistant cellulose acetate material.

8. The method for preparing a thermal cellulose acetate material according to claim 7, characterized in that: In step S1, the mixture is dried in a vacuum oven at 70°C for 24 hours.

9. Use of a thermal cellulose acetate material according to any one of claims 1 to 6, characterized in that: The thermal cellulose acetate material is used for manufacturing spectacle frames and high-grade tool handles.

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