阅读说明：本技术 一种改性三聚氰胺氰尿酸盐的制备方法 (Preparation method of modified melamine cyanurate ) 是由 赵震 郭建树 王盛海 于 2021-02-03 设计创作，主要内容包括：本发明提供一种改性三聚氰胺氰尿酸盐的制备方法,该制备方法是在一定的预热温度下,依次加入改性剂、三聚氰胺、氰尿酸进行反应；所述改性剂,为山梨糖醇、新戊四醇、淀粉中的一种或两种,采用本发明的制备方法,改性剂对MCA原有的氢键结构进行调控,使得制得的三聚氰胺氰尿酸盐粒径较大且尺寸分散均匀,粒径达到18-21μm,比表面积500-580m2/m3,制得的三聚氰胺氰尿酸盐在基体中分散性好,使用添加量少,对基体材料的性能影响小,阻燃效果较为优异。(The invention provides a preparation method of modified melamine cyanurate, which comprises the steps of sequentially adding a modifier, melamine and cyanuric acid at a certain preheating temperature for reaction; the modifier is one or two of sorbitol, neopentyl glycol and starch, and the preparation method provided by the invention is adopted, and the modifier regulates and controls the original hydrogen bond structure of MCA, so that the prepared melamine cyanurate has a large particle size and uniform size dispersion, the particle size reaches 18-21 mu m, the specific surface area is 500-580m2/m3, the prepared melamine cyanurate has good dispersibility in a matrix, the use addition amount is small, the influence on the performance of a matrix material is small, and the flame retardant effect is excellent.)

1. A preparation method of modified melamine cyanurate is characterized in that the preparation method comprises the steps of sequentially adding a modifier, melamine and cyanuric acid at a certain preheating temperature for reaction; the modifier is one or two of sorbitol, pentaerythritol and starch.

2. The method according to claim 1, wherein the modifier is added in an amount of 4-10% by mass based on the total mass of the melamine and the cyanuric acid.

3. The process according to claim 1, wherein the molar ratio of melamine to cyanuric acid is from 1 to 1.05: 1.

4. the method of claim 1, wherein the preheating temperature is 40-50 ℃.

5. The method according to claim 1, wherein the reaction temperature is 70 to 80 ℃ and the reaction time is 30 to 40 min.

6. The method according to claim 1, wherein a solvent is further added during the reaction, wherein the solvent is water and the amount of the solvent added is 3-8 times of the total mass of the melamine and the cyanuric acid.

7. The method as claimed in claim 1, wherein the modified melamine cyanurate has a D50 of 18-21 μm and a specific surface area of 500-580m2/m 3.

Technical Field

The invention belongs to the technical field of preparation of halogen-free flame-retardant materials, and particularly relates to a preparation method of modified melamine cyanurate.

Background

Melamine cyanurate, abbreviated as MCA, is a typical nitrogen-based flame retardant, has high nitrogen content, MCA has various advantages of extremely low application cost, excellent electrical properties, mechanical properties, colorability and the like, and meanwhile, MCA has the advantage of easy processing due to excellent balance between good thermal stability and efficient flame retardance when being used as a mixed additive to manufacture a flame-retardant master batch. Can be used in various thermoplastic plastics, including Polyamide (PA), glass fiber reinforced polyamide, PBT, glass fiber reinforced PBT, PP, PS/HIPS, TPU, PET/PBT, textile and the like, and thermal solid resin, including epoxy resin, PU foam and unsaturated polyester. The flame retardant is used together with halogen series, antimony series and phosphorus series flame retardants, particularly is used together with APP as an intumescent flame retardant, and has good synergistic effect.

In view of the advantages of MCA, the MCA can be widely applied to processing, and can be used as a halogen-free flame retardant in polyamide, polyester, polyformaldehyde, polyurethane, synthetic rubber and plastic products, a solid lubricating additive added in lubricating oil, grease and paste, a flame-retardant and delustering auxiliary added in fireproof paint, and a lubricant added in cosmetics. The flame retardant is applied to the flame retardance of polymers such as epoxy resin and the like, is particularly suitable for two pure nylons, namely nylon 6 and nylon 66, and can easily achieve the flame retardant effect of UL 94V-0 level; the MCA flame-retardant nylon has the comprehensive performance better than Decabromodiphenylethane (DBP), and especially the electrical performance CTI of MCA is greatly better than that of DBP. However, MCA is directly sublimed and decomposed by heat without melting process, and MCA is dispersed in a resin matrix in a rigid particle state during melt blending with a polymer, and the dispersed state thereof has a great dependence on the initial particle size of the flame retardant particles.

The invention patent CN2014107678896 discloses that cyanuric acid is used as a modifier to prepare a modified melamine cyanurate flame retardant, the invention emphasizes a modified melamine cyanurate flame retardant with a novel structure and the synergistic flame-retardant effect of sulfur and triazine ring, but the flame retardant of the invention only improves the flame-retardant effect, but the modified melamine cyanurate has poor heat resistance and poor thermal stability.

CN106700130B discloses a composite modified melamine cyanurate fire retardant, its preparation method and application, the invention is that melamine, cyanuric acid, complexing agent and heat stabilizer are added into water to stir and disperse, then heating reaction is carried out to obtain viscous paste of modified melamine cyanurate.

The patent document CN104311500B of Jinan Thai Limited discloses a method for preparing melamine cyanurate by a sol modification method, wherein the nano MCA (300nm-500nm) prepared by the method has small crystal form and large specific surface area, and influences the processing flowability and dispersibility of the MCA although the flame retardance and the mechanical properties are improved.

Disclosure of Invention

In order to solve the problems in the prior art and further optimize the prior art, the invention provides a preparation method of modified melamine cyanurate, so as to achieve the purposes of improving the dispersibility of MCA in a matrix and improving the flame retardant property, the mechanical property and the heat resistance of a product.

In order to solve the technical problems, the invention adopts the following technical scheme:

a preparation method of modified melamine cyanurate is characterized in that the preparation method comprises the steps of sequentially adding a modifier, melamine and cyanuric acid at a certain preheating temperature for reaction; the modifier is one or two of sorbitol, pentaerythritol and starch;

preferably sorbitol and starch or pentaerythritol and starch;

preferably, the mass ratio of sorbitol to starch is 3-4: 1;

the addition amount of the modifier is 4-10% of the total mass of the melamine and the cyanuric acid;

the molar ratio of the melamine to the cyanuric acid is 1-1.05: 1;

the preheating temperature is 40-50 ℃;

the reaction temperature is 70-80 ℃, and the reaction time is 30-40 min;

in the reaction, a solvent is also added, wherein the solvent is water, and the addition amount of the solvent is 3-8 times of the total mass of the melamine and the cyanuric acid;

the D50 of the modified melamine cyanurate is 18-21 mu m, and the specific surface area is 500-580m2/m 3.

By adopting the technical scheme, the invention has the beneficial effects that:

1. by adopting the preparation method, the modifier regulates and controls the original hydrogen bond structure of MCA, so that the prepared melamine cyanurate has larger particle size and uniform size dispersion, the particle size reaches 18-21 mu m, and the specific surface area is 500-580m2/m 3;

2. the melamine cyanurate prepared by the preparation method has good flame retardance, and the flame retardant grade of 1.6mm reaches V0-V1 when MCA prepared by the preparation method is added into nylon 66 to prepare a flame retardant material;

3. the melamine cyanurate prepared by the preparation method has good heat resistance, and the thermal weight loss (1%) temperature is 331-336 DEG C

4. By adopting the preparation method, the prepared melamine cyanurate has good dispersibility in the matrix, and the prepared nylon 66 flame-retardant material has the tensile strength of 17-19MPa and the elongation at break of 80-83.5 percent;

5. the preparation method of the invention is adopted to prepare the melamine cyanurate, and the yield reaches 99.9 percent and above;

6. the melamine cyanurate prepared by the preparation method has small addition amount and less influence on the performance of a matrix material.

The specific implementation mode is as follows:

the invention is further illustrated below with reference to specific examples.

Example 1:

adding 500g of water into a reaction kettle, heating to 40 ℃, sequentially adding 6g of sorbitol, 2g of starch, 68.5g of melamine and 69.4g of cyanuric acid under the condition of stirring, heating to 70 ℃, reacting for 30 minutes, filtering while hot, and drying to obtain an MCA product, wherein the detection shows that D50=18.3 micrometers, the specific surface area is 508.5m2/m3, the yield is 99.90%, and the thermal weight loss (1%) is 331 ℃.

Example 2:

adding 500g of water into a reaction kettle, heating to 45 ℃, sequentially adding 6g of neopentyl glycol, 2g of starch, 68.8g of melamine and 69.4g of cyanuric acid under the stirring condition, heating to 75 ℃, reacting for 30 minutes, filtering while hot, and drying to obtain an MCA product, wherein the detection shows that D50=19.0 micrometers, the specific surface area is 531.8m2/m3, the yield is 99.95%, and the thermal weight loss (1%) is 302 ℃.

Example 3:

adding 550g of water into a reaction kettle, heating to 50 ℃, sequentially adding 8g of sorbitol, 68.5g of melamine and 69.4g of cyanuric acid under the condition of stirring, heating to 80 ℃, reacting for 40 minutes, filtering while hot, drying to obtain an MCA product, detecting that D50=20.3 micrometers, the specific surface area is 559.8m2/m3, the yield is 99.98%, and the thermal weight loss (1%) is 335 ℃.

Example 4:

adding 500g of water into a reaction kettle, heating to 40 ℃, sequentially adding 8g of sorbitol, 3g of starch, 68.5g of melamine and 69.4g of cyanuric acid under the condition of stirring, heating to 70 ℃, reacting for 30 minutes, filtering while hot, and drying to obtain an MCA product, wherein the detection shows that D50=18.5 micrometers, the specific surface area is 526.8m2/m3, the yield is 99.92%, and the thermal weight loss (1%) is 334 ℃.

Example 5:

adding 500g of water into a reaction kettle, heating to 45 ℃, sequentially adding 8g of neopentyl glycol, 3g of starch, 68.8g of melamine and 69.4g of cyanuric acid under the stirring condition, heating to 75 ℃, reacting for 30 minutes, filtering while hot, and drying to obtain an MCA product, wherein the detection shows that D50=19.5 micrometers, the specific surface area is 544.7m2/m3, the yield is 99.93%, and the thermal weight loss (1%) is 333 ℃.

Example 6:

adding 500g of water into a reaction kettle, heating to 50 ℃, sequentially adding 10g of sorbitol, 68.8g of melamine and 69.4g of cyanuric acid under the condition of stirring, heating to 80 ℃, reacting for 40 minutes, filtering while hot, and drying to obtain an MCA product, wherein the detection result shows that D50=20.5 micrometers, the specific surface area is 582.2m, 2/m3, the yield is 99.95%, and the thermal weight loss (1%) is 336 ℃.

1. The application experiments of the common MCA product prepared by the conventional method, the MCA of the invention and the sol modified MCA are carried out:

MCA16kg, nylon 66100kg and antioxidant 0.2kg are taken, evenly mixed, and then the materials are transferred into a double-screw extruder to be extruded at 220 ℃ and injected, and the product performance is shown in the following table:

2. the addition of MCA is reduced, MCA prepared in the embodiment 4 of the invention, 100kg of nylon 66 and 0.2kg of antioxidant are uniformly mixed, then the materials are transferred into a double-screw extruder to be extruded at 220 ℃, and the product performance is shown in the following table after injection molding:

experimental data show that the addition amount of the MCA product related to the patent document is obviously lower than that of the common MCA and sol modified MCA products, the flame retardant property is better, the process is simple, the process is easy to realize, the product particle size is uniform, the dispersibility is good, the same effect can be achieved with small addition amount, the influence on the performance of a matrix material is small, and the mechanical property is excellent.

Finally, it should be noted that: although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art will understand that various changes, modifications and substitutions can be made without departing from the spirit and scope of the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.