阅读说明：本技术 一种可生物降解材料用无机成核剂的制备方法 (Preparation method of inorganic nucleating agent for biodegradable material ) 是由 张利刚 陈奇 田洪池 陈军 杨书海 郝艳平 王凡 陈伟 陈文飞 刘杨 左振杰 于 2021-08-31 设计创作，主要内容包括：一种可生物降解材料用无机成核剂的制备方法,采用富氮类前驱物作为制备的原料,制备工序包括富氮类前驱物高温煅烧制备氮化碳材料和微米氮化碳表面羟基化改性。本发明基于富氮类前驱物制得的成品,具有原料来源广、成本低的优点。本发明高温煅烧制得的微米氮化碳材料作为成核剂,经碱液处理后表面羟基含量提高,其表面羟基数量的增加可提高其与可降解树脂(可生物降解塑料)的端羟基相容性,可实现微米成核剂在可降解树脂中的均匀分散,碱处理可导致微米氮化碳成核剂表面发生刻蚀,增大其比表面积,从而提高与树脂的结合能力,进而为提高注塑件成品质量起到了有力技术支撑。基于上述,本发明具有好的应用前景。(A process for preparing the inorganic nucleating agent used for biodegradable material features that the nitrogen-enriched precursor is used as raw material, and the preparing process includes high-temp calcining of nitrogen-enriched precursor to prepare carbon nitride material and modifying the surface of micron carbon nitride. The finished product prepared based on the nitrogen-rich precursor has the advantages of wide raw material source and low cost. The micron carbon nitride material prepared by high-temperature calcination is used as a nucleating agent, the content of surface hydroxyl groups is improved after alkali liquor treatment, the compatibility of the surface hydroxyl groups with terminal hydroxyl groups of degradable resin (biodegradable plastic) can be improved by increasing the number of the surface hydroxyl groups, the micron nucleating agent can be uniformly dispersed in the degradable resin, the surface of the micron carbon nitride nucleating agent can be etched by alkali treatment, the specific surface area of the micron carbon nitride nucleating agent is increased, the binding capacity with the resin is improved, and a powerful technical support is provided for improving the quality of finished injection molding parts. Based on the above, the invention has good application prospect.)

1. A method for preparing inorganic nucleating agent for biodegradable material is characterized in that nitrogen-rich precursor is used as raw material for preparation, and the preparation process comprises the steps of preparing carbon nitride material by high-temperature calcination of the nitrogen-rich precursor and surface hydroxylation modification of micron carbon nitride; the preparation method of the carbon nitride material by high-temperature calcination of the nitrogen-rich precursor comprises the following steps of weighing the nitrogen-rich precursor, transferring the nitrogen-rich precursor into a crucible, placing the crucible into a muffle furnace for high-temperature calcination, cooling the mixture to room temperature, and grinding the mixture by a grinder to obtain a light yellow powdery carbon nitride material, wherein the yield of carbon nitride is 40-60% according to different calcination temperatures; the surface hydroxylation modification step of the micron carbon nitride is as follows, step A: preparing an alkaline aqueous solution, transferring the alkaline aqueous solution to a hydrothermal reaction kettle with a polytetrafluoroethylene lining, adding a powdery carbon nitride material, fully stirring and uniformly mixing, transferring to an oven, preserving heat for a period of time, and cooling to room temperature; and B: and filtering, washing and drying the alkaline mixed reaction liquid containing the carbon nitride material after the hydrothermal reaction for multiple times to obtain the surface hydroxylation modified carbon nitride inorganic nucleating agent, wherein the yield of the carbon nitride inorganic nucleating agent is 30-60% according to the difference of alkali types and hydrothermal temperatures.

2. The method of claim 1, wherein the nitrogen-rich precursor comprises urea, cyanamide, dicyandiamide, melamine, preferably dicyandiamide 100g, cooling to room temperature, and grinding to obtain about 50g of pale yellow powdered carbon nitride.

3. The method for preparing an inorganic nucleating agent for biodegradable materials according to claim 1, wherein the high-temperature calcination temperature is 400 ℃ to 600 ℃, preferably 550 ℃, the calcination time is 0.5h to 4h, preferably 2h, and the atmosphere of the high-temperature calcination gas in the muffle furnace is air.

4. The method of claim 1, wherein the alkaline substance in the alkaline aqueous solution comprises one of sodium hydroxide, potassium hydroxide and ammonia water, and the concentration is 0.5mol// L to 5mol/L, preferably 1mol// L aqueous solution of sodium hydroxide.

5. The method for preparing an inorganic nucleating agent for biodegradable materials according to claim 1, characterized in that the hydrothermal temperature is 50 ℃ to 200 ℃, preferably 90 ℃; the hydrothermal time is 0.5h to 4h, preferably 2 h.

6. The method for preparing the inorganic nucleating agent for the biodegradable material according to claim 1, wherein the oven temperature is preferably 120 ℃ and the holding time is preferably 1h, about 25g of the micron carbon nitride nucleating agent with the hydroxylation-treated surface is obtained, and the yield is about 50%.

Technical Field

The invention relates to the technical field of preparation methods of raw materials for producing injection molding parts, in particular to a preparation method of an inorganic nucleating agent for a biodegradable material.

Background

In the production of injection molding parts, inorganic nucleating agent materials (such as superfine talcum powder, titanium dioxide, magnesium silicate and the like) are required to be used, the inorganic nucleating agent materials have the advantages of low price, obvious modification effect and the like, and the nucleating agent serving as degradable base material resin (biodegradable material) has attracted attention, mainly plays a role in improving the crystallization density of various raw materials and auxiliary materials for producing the injection molding parts and micronizing and homogenizing the crystal grain structure, finally improves the physical and mechanical properties (such as rigidity, gloss, thermal deformation, transparency and the like) of injection molding part products (plastic products) and improves the production efficiency. But the inorganic nucleating agent is limited by the characteristics of the existing inorganic nucleating agent material, has the defects of small size, large specific surface area, high surface energy and the like, so that the inorganic nucleating agent is extremely easy to agglomerate and the biodegradable material is difficult to disperse and fuse fully in application, the micro-scale effect cannot be exerted to the maximum extent, and the quality of the prepared injection molding finished product is greatly influenced. Therefore, the problem of uniform dispersion of inorganic particles in polymer resins has become a technical bottleneck restricting the use of the polymer resins as efficient nucleating agents.

Disclosure of Invention

In order to overcome the defects of small size, large specific surface area, high surface energy and the like of the existing inorganic nucleating agent materials due to characteristic limitation, which causes that the inorganic nucleating agent materials are easy to agglomerate mutually and are difficult to be fully dispersed and fused with biodegradable materials, and cannot exert the micro-scale effect to the maximum extent, the invention provides the finished product prepared based on the nitrogen-rich precursor, which has the advantages of wide raw material source and low cost, improves the compatibility with the terminal hydroxyl of the biodegradable material (degradable resin) through the surface hydroxylation modification in the application, realizes the uniform dispersion in the degradable resin, and the specific surface area is increased due to the surface etching, so that the binding capacity with resin is improved, and further provides a powerful technical support for improving the quality of finished injection molding parts.

The technical scheme adopted by the invention for solving the technical problems is as follows:

a method for preparing inorganic nucleating agent for biodegradable material is characterized in that nitrogen-rich precursor is used as raw material for preparation, and the preparation process comprises the steps of high-temperature calcination of the nitrogen-rich precursor to prepare carbon nitride material and surface hydroxylation modification of the carbon nitride material; the preparation method of the carbon nitride material by high-temperature calcination of the nitrogen-rich precursor comprises the following steps of weighing the nitrogen-rich precursor, transferring the nitrogen-rich precursor into a crucible, placing the crucible into a muffle furnace for high-temperature calcination, cooling the mixture to room temperature, and grinding the mixture by a grinder to obtain a light yellow powdery carbon nitride material, wherein the yield of carbon nitride is 40-60% according to different calcination temperatures; the surface hydroxylation modification step of the micron carbon nitride is as follows, step A: preparing an alkaline aqueous solution, transferring the alkaline aqueous solution to a hydrothermal reaction kettle with a polytetrafluoroethylene lining, adding a powdery carbon nitride material, fully stirring and uniformly mixing, transferring to an oven, preserving heat for a period of time, and cooling to room temperature; and B: and filtering, washing and drying the alkaline mixed reaction liquid containing the carbon nitride material after the hydrothermal reaction for multiple times to obtain the surface hydroxylation modified carbon nitride inorganic nucleating agent, wherein the yield of the carbon nitride inorganic nucleating agent is 30-60% according to the difference of alkali types and hydrothermal temperatures.

Further, the nitrogen-rich precursor comprises cyanamide substances including urea, cyanamide, dicyandiamide and melamine, preferably 100g dicyandiamide, and is cooled to room temperature and ground to obtain about 50g light yellow powdery carbon nitride material.

Further, the high-temperature calcination temperature is 400-600 ℃, preferably 550 ℃, the calcination time is 0.5-4 h, preferably 2h, and the atmosphere of the high-temperature calcination gas in the muffle furnace is air.

Further, the alkaline substance of the alkaline aqueous solution comprises one of sodium hydroxide, potassium hydroxide and ammonia water, and the concentration of the alkaline aqueous solution is 0.5 mol/L-5 mol/L, and preferably 1 mol/L of the sodium hydroxide aqueous solution.

Further, the hydrothermal temperature is 50-200 ℃, preferably 90 ℃; the hydrothermal time is 0.5h to 4h, preferably 2 h.

Furthermore, the oven temperature is preferably 120 ℃, and the heat preservation time is preferably 1h, so that about 25g of the micron carbon nitride nucleating agent subjected to surface hydroxylation treatment is obtained, and the yield is about 50%.

The invention has the beneficial effects that: the finished product prepared based on the nitrogen-rich precursor has the advantages of wide raw material source and low cost. The micron carbon nitride material prepared by high-temperature calcination is used as a nucleating agent, the content of surface hydroxyl groups is improved after alkali liquor treatment, the compatibility of the micron carbon nitride material and degradable resin (biodegradable plastic) terminal hydroxyl groups can be improved by increasing the number of the surface hydroxyl groups, the micron nucleating agent can be uniformly dispersed in the degradable resin, the surface of the micron carbon nitride nucleating agent can be etched by alkali treatment, the specific surface area of the micron carbon nitride nucleating agent is increased, the binding capacity with the resin is improved, and a powerful technical support is provided for improving the quality of finished injection molding parts. Based on the above, the invention has good application prospect.

Drawings

FIG. 1 is a block diagram showing a preparation method of an inorganic nucleating agent for biodegradable materials of the present invention.

FIG. 2 is a microscopic electron micrograph of the distribution of carbon nitride on the surface of the injection molded part in the 1% carbon nitride filled polylactic acid material of the invention.

FIG. 3 is a graph comparing DSC curves of the pure polylactic acid of the present invention and the 1% carbon nitride-filled polylactic acid.

Detailed Description

FIG. 1 shows a preparation method of an inorganic nucleating agent for biodegradable materials, wherein a nitrogen-rich precursor is used as a raw material for preparation, and the preparation process comprises the steps of preparing a carbon nitride material by high-temperature calcination of the nitrogen-rich precursor and surface hydroxylation modification of the carbon nitride material; the preparation method of the carbon nitride material by high-temperature calcination of the nitrogen-rich precursor comprises the following steps: weighing a nitrogen-rich precursor, transferring the nitrogen-rich precursor into a crucible, placing the crucible into a muffle furnace for high-temperature calcination, cooling to room temperature, and grinding by using a grinder to obtain a light yellow powdery carbon nitride material, wherein the yield of the carbon nitride is 40-60% according to different calcination temperatures; the surface hydroxylation modification step of the micron carbon nitride is as follows, step A: preparing an alkaline aqueous solution, transferring the alkaline aqueous solution to a hydrothermal reaction kettle with a polytetrafluoroethylene lining, adding a powdery carbon nitride material, fully stirring and uniformly mixing, transferring to an oven with a certain temperature, preserving the temperature for a period of time, and cooling to room temperature; and B: and filtering, washing and drying the alkaline mixed reaction liquid containing the carbon nitride material after the hydrothermal reaction for multiple times to obtain the surface hydroxylation modified carbon nitride inorganic nucleating agent, wherein the yield of the carbon nitride inorganic nucleating agent is 30-60% according to the difference of alkali types and hydrothermal temperatures. The nitrogen-rich precursor includes cyanamide substances such as urea, cyanamide, dicyandiamide, melamine and the like, and in this embodiment, 100g of dicyandiamide is preferred, and the carbon nitride material is cooled to room temperature and ground to obtain about 50g of light yellow powdery carbon nitride material. The high-temperature calcination temperature is 400 ℃ to 600 ℃, the preferred temperature in the embodiment is 550 ℃, the calcination time is 0.5h to 4h, the preferred time in the embodiment is 2h, and the atmosphere of the high-temperature calcination gas in the muffle furnace is air. The alkaline substance of the alkaline aqueous solution includes one of sodium hydroxide, potassium hydroxide, ammonia water and the like, and the concentration is 0.5mol// L to 5mol/L, and the 1mol// L aqueous solution of sodium hydroxide is preferred in the embodiment. The hydrothermal temperature is 50-200 ℃, and the optimal temperature is 90 ℃; the hydrothermal time is 0.5h to 4h, preferably 2 h. The oven temperature is preferably 120 ℃, the heat preservation time is preferably 1h, about 25g of micron carbon nitride nucleating agent with hydroxylation treatment on the surface is obtained, and the yield is about 50%.

As shown in FIG. 1, the finished product prepared based on the nitrogen-rich precursor has the advantages of wide raw material source and low cost. As shown in figure 2, the micron carbon nitride material prepared by high-temperature calcination is used as a nucleating agent, the content of surface hydroxyl groups is increased after the treatment of alkali liquor, the compatibility of the micron carbon nitride material with terminal hydroxyl groups of degradable resin (biodegradable plastic) can be improved by increasing the number of the surface hydroxyl groups, the micron nucleating agent can be uniformly dispersed in the degradable resin, and the surface of the micron carbon nitride nucleating agent can be etched by alkali treatment, so that the specific surface area of the micron carbon nitride nucleating agent is increased, the binding capacity of the micron carbon nitride nucleating agent with the resin is improved, and a powerful technical support is provided for improving the quality of finished injection molding parts.

Fig. 3 shows that the existing injection molded part adopts pure polylactic resin alone, and after the polylactic resin is filled with the micron carbon nitride nucleating agent of the present invention (added into the polylactic resin in a proportion of 1%), the micron carbon nitride nucleating agent of the present invention fills the polylactic resin, and the micron carbon nitride nucleating agent significantly promotes the cold crystallization property of the polylactic acid in the cooling process, so as to form an obvious cold crystallization peak. In FIG. 3, 1 is a pure polylactic acid resin; 2, adding 1 percent of micron carbon nitride nucleating agent to fill the polylactic resin. The following table shows the tensile test data and melt flow rate comparison of injection molded parts made of polylactic acid resin filled with 1% micron carbon nitride nucleating agent (from the table, the tensile strength, modulus and strain at break of injection molded parts made of polylactic acid resin filled with micron carbon nitride nucleating agent are significantly higher than those of injection molded parts made of polylactic acid resin, and the decrease in melt flow rate proves that the nucleating agent forms good interface bonding with polylactic acid resin and reduces the fluidity of the resin)

Note: the melt flow rate was measured under the conditions of 2.16kg, 190 ℃.

While there have been shown and described what are at present considered the fundamental principles and essential features of the invention and its advantages, it will be apparent to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, but is capable of other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

Furthermore, it should be understood that although the present description refers to embodiments, the embodiments do not include only one independent technical solution, and such description is only for clarity, and those skilled in the art should take the description as a whole, and the technical solutions in the embodiments may be appropriately combined to form other embodiments that can be understood by those skilled in the art.