CN114478145A - Gas generating agent with excellent water repellency and preparation method thereof - Google Patents

Abstract

The invention provides a gas generating agent with excellent water repellency and a preparation method thereof, wherein the gas generating agent comprises the following components in parts by mass: 25% -60% of organic fuel; 37% -59% of an oxidant; 1 to 10 percent of adhesive added with water repellent agent, the total mass percent of each component is 100 percent, and the dosage is calculated by the solid content of the effective component. The improved gas generating agent is added with the polymer adhesive with the water-resistant agent, so that the water repellency of the gas generating agent is enhanced, the environmental adaptability is improved, the bonding of particles due to moisture absorption is prevented, the particle fluidity can be increased, the tabletting consistency is ensured, and the tabletting speed is improved.

Description

Gas generating agent with excellent water repellency and preparation method thereof

Technical Field

The invention belongs to the technical field of pyrotechnic gas generants for automobile safety airbags, and particularly relates to a gas generant with excellent water repellency and a preparation method thereof.

Background

At present, the technology relating to the protection of motor vehicle occupants has been greatly developed, the latest generation of motor vehicles incorporate several safety systems of the airbag type in the passenger compartment, the combustion gases of pyrotechnic gas generants ensure the operation of the safety systems; among airbag-type systems, there are front airbags (for drivers or passengers) and side airbags (curtain, chest protection).

The main disadvantages of the gas generating agent prepared from an oxidizing agent represented by Basic Copper Nitrate (BCN) and an organic fuel represented by Guanidine Nitrate (GN) are that the raw materials and the pressed materials have high hygroscopicity, the requirement on the assembly environment is high, and the assembly in a low-humidity environment is required. The gas generating agent is inevitably affected by the humidity of the environment when used for a long period of time. The process is slow, but the service life of the automobile is long and accumulated, particularly the service life of the automobile is easy to exceed 10 years, after the gas generating agent absorbs certain moisture, the combustion performance is affected, ignition delay is caused, and the gas generating agent even completely fails in severe cases, so that the expected gas output curve cannot be reached.

The prior art adopts helium filling to check the sealing performance or adds some molecular sieves as moisture absorbents in the gas generating agent to solve the problems, but the effect is not obvious and the production cost of the generating agent is high. Therefore, how to effectively solve the problem of low cost and hygroscopicity of the gas generating agent is an urgent need.

Disclosure of Invention

The present inventors have made intensive studies in order to overcome the drawbacks of the prior art, and have provided a gas generating agent excellent in water repellency and a method for producing the same, which are capable of effectively preventing and retarding the permeation of water in the gas generating agent by adjusting the components thereof, thereby enhancing the moisture resistance of the gas generating agent and ensuring the stability of the output performance of the gas generating agent for a long period of time, thereby completing the present invention.

The technical scheme provided by the invention is as follows:

in a first aspect, a gas generating agent with excellent water repellency comprises the following components in parts by mass: 25% -60% of organic fuel; 37% -59% of an oxidant; 1 to 10 percent of adhesive added with water repellent agent, the total mass percent of each component is 100 percent, and the dosage is calculated by the solid content of the effective component.

In a second aspect, a method for producing a gas generating agent excellent in water repellency, comprising the steps of:

step 1, weighing organic fuel and oxidant according to the designed component proportion;

step 2, weighing the adhesive added with the water repellent agent according to the designed component proportion, and uniformly mixing the adhesive with the organic fuel and the oxidant;

and 3, adopting wet granulation, dry granulation or spray granulation to press the mixture into tablets.

According to the gas generating agent with excellent water repellency and the preparation method thereof provided by the invention, the following beneficial effects are achieved:

(1) according to the gas generating agent with excellent water repellency and the preparation method thereof, the improved gas generating agent component is added with the adhesive mixed with the water repellent agent, so that the moisture resistance of the gas generating agent is improved, and the risks of combustion and output uncertainty caused by moisture absorption of the gas generating agent in a high-humidity environment are reduced;

(2) according to the gas generating agent with excellent water repellency and the preparation method thereof, the improved gas generating agent component is added with the adhesive mixed with the water repellent agent, so that the particle fluidity can be increased, the tabletting consistency is ensured, and the tabletting speed is increased;

(3) the improved gas generating agent preparation method disclosed by the invention has the advantages of simple process, low cost and the like;

(4) the improved gas generating agent is used in a gas generator of a passive airbag system of an automobile and is suitable for inflating various airbags such as front, passenger side, side airbags, curtain airbags and the like.

(5) The water repellent formula provided by the invention is not limited to a gas generating agent, and can also be used for a propellant formula and an automatic ignition powder formula.

Detailed Description

The features and advantages of the present invention will become more apparent and appreciated from the following detailed description of the invention.

The word "exemplary" is used exclusively herein to mean "serving as an example, embodiment, or illustration. Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments.

According to a first aspect of the present invention, there is provided a gas generating agent excellent in water repellency, comprising the following components in parts by mass:

25 to 60 percent of organic fuel, preferably 35 to 45 percent;

37 to 59 percent of oxidant, preferably 40 to 56 percent;

1 to 10 percent of adhesive added with water repellent agent, preferably 3 to 6 percent;

the total mass percent of all the components is 100 percent, and the dosage is calculated by the solid content of the effective components.

In a preferred embodiment, the organic fuel is selected from at least one of 5-aminotetrazole, guanidine nitrate or nitroguanidine and derivatives thereof.

In a preferred embodiment, the oxidizing agent comprises a primary oxidizing agent, which is basic copper nitrate and strontium nitrate. The oxidant can also comprise 0-5% of a secondary oxidant, and the secondary oxidant is selected from at least one of metal oxide, perchlorate, hypochlorite or nitrate and is used for improving the combustion speed and the gas composition. The metal oxides include, but are not limited to, iron oxide, copper oxide; the perchlorate salts include, but are not limited to, Ammonium Perchlorate (AP) or potassium perchlorate; the nitrate salts include, but are not limited to, potassium nitrate or sodium nitrate; such hypochlorites include, but are not limited to, potassium hypochlorite, sodium hypochlorite.

In a preferred embodiment, the binder is selected from at least one of cellulose derivatives and salts such as cellulose, hemicellulose, methyl cellulose salts, cellulose acetate and the like, polyvinyl alcohol, guar gum, starch, modified starch, vinyl acetate styrene white latex, styrene butadiene latex, butyronitrile latex, soy protein, acrylic emulsion and styrene acrylic copolymer emulsion, various emulsion modified by copolymerization with acrylic acid, various emulsion modified by copolymerization with styrene and the like, and preferably cellulose.

The adding mode of the adhesive can be determined according to the property and the process of the formula materials, the adhesive can be directly weighed into the formula in the form of dry powder or liquid, or can be prepared into an aqueous solution and then added with water, and the solid content is generally 10-60 percent, preferably 50 percent.

In a preferred embodiment, the water repellent agent is at least one selected from urea formaldehyde resin, melamine formaldehyde resin, polyamide polyurea resin or polyamide polyamine epichlorohydrin resin, and is used in an amount of 1% to 8% (by solid content) of the binder, preferably in an amount of 3% to 6%.

In order to optimize the process performance and combustion performance of the improved gas generating agent formula, various combustion rate catalysts, process aids, low-temperature slag bonding agents and the like can be added into the formula, and the components can also influence the calculation of oxygen balance and the formation of residues; the content of the organic fuel, the oxidant and the binder added with the water repellent agent in the improved gas generating agent is more than 90 percent of the total mass. Because of differences in the gas generant forming process, generant design and transfer charge, the oxygen balance of the formulation is affected when the binder containing organic materials is added, and it is considered in the formulation calculation, the oxygen balance is controlled to be 3% to-5%, preferably-1.5% to-3.5% in the present invention. The composition of the modified gas generant formulation may be appropriately adjusted depending on the residue form and gas composition. When used for other purposes, the oxygen balance may not be considered.

The improved preparation method of the gas generating agent adopts wet granulation, dry granulation, tabletting after spray granulation or direct dry powder pressing; the compressed improved gas generant tablets are mesoporous or solid and the diameter and thickness of the tablets may be adjusted depending on the properties of the generant.

The inventor finds that after the current organic fuel and oxidant or conventional burning rate catalyst, process auxiliary agent, low-temperature slagging agent and the like are added to form a formula in long-term production practice, the fluidity of particles in the material is poor, the tabletting consistency is difficult to ensure, and the yield is low. After a large number of researches, the water repellent agent is selected to be urea-formaldehyde resin, melamine formaldehyde resin, polyamide polyurea resin or polyamide polyamine epoxy chloropropane resin, so that the particle fluidity can be effectively improved, and the problem caused by tabletting of a product is solved.

According to a second aspect of the present invention, there is provided a method for producing a gas generating agent excellent in water repellency, comprising the steps of:

step 1, weighing organic fuel and oxidant according to the designed component proportion;

step 2, weighing the adhesive added with the water repellent agent according to the designed component proportion, and uniformly mixing the adhesive with the organic fuel and the oxidant;

and 3, adopting wet granulation, dry granulation or spray granulation and then pressing into tablets, or directly pressing dry powder into tablets.

In a preferred embodiment, in steps 1 and 2, the selection of the components and the ratio is the same as in the first aspect, and will not be described herein again.

In a preferred embodiment, in step 3, the process parameters for tabletting with phente P2020 are as follows:

for wet granulation followed by compression into tablets, the process parameters included: the rotating speed is 65-70 r/min, and the pressure is 6.0-6.5 kN;

for dry granulated and compressed tablets, the process parameters included: the rotating speed is 65-70 r/min, and the pressure is 6.0-6.5 kN;

for spray granulation followed by compression into tablets, the process parameters included: the rotating speed is 70-75 r/min, and the pressure is 6.0-6.5 kN;

for direct dry powder direct compression, the process parameters included: the rotation speed is 55-60 r/min, and the pressure is 6.0-6.5 kN.

Examples

Example 1

4.0kg of guanidine nitrate, 5.2kg of basic copper nitrate and 300g of strontium nitrate are respectively weighed; weighing 1kg of sodium carboxymethylcellulose solution with the solid content of 50 percent and 30g of melamine formaldehyde resin, mixing, adding into 10kg of water with the temperature of 40 ℃, uniformly stirring, carrying out spray granulation and drying to obtain granules with good fluidity, pressing into circular tablets with the diameter of 5mm and the thickness of 2mm by using a rotary tablet press at the rotating speed of 70r/min, the filling capacity of 5mm and the pressure of 6.0kN, and drying for 4 hours in an oven at the temperature of 110 ℃, wherein the water content of the improved gas generant is controlled to be less than or equal to 0.3 percent, and the actual measurement value is 0.19 percent.

Example 2

4.0kg of guanidine nitrate, 5.2kg of basic copper nitrate and 300g of strontium nitrate are respectively weighed; weighing 1kg of sodium carboxymethylcellulose solution with the solid content of 50 percent and 30g of polyamide polyurea resin, mixing, adding into 10kg of water with the temperature of 40 ℃, uniformly stirring, carrying out spray granulation and drying to obtain granules with good fluidity, pressing into round tablets with the diameter of 5mm and the thickness of 2mm by using a rotary tablet press at the rotating speed of 70r/min, the filling capacity of 5mm and the pressure of 6.0kN, and drying for 4 hours in an oven at the temperature of 110 ℃, wherein the water content of the improved gas generating agent is controlled to be less than or equal to 0.3 percent, and the actual measurement value is 0.24 percent.

Example 3

4.0kg of guanidine nitrate, 5.2kg of basic copper nitrate and 300g of strontium nitrate are respectively weighed; weighing 1kg of sodium carboxymethylcellulose solution with the solid content of 50 percent and 30g of polyamide polyamine epichlorohydrin resin, mixing, adding into 10kg of water with the temperature of 40 ℃, uniformly stirring, carrying out spray granulation and drying to obtain particles with good fluidity, mechanically pressing into circular tablets with the diameter of 5mm and the thickness of 2mm by using a rotary tablet press at the rotating speed of 70r/min, the filling amount of 5mm and the pressure of 6.0kN, and drying for 4 hours in an oven at the temperature of 110 ℃, wherein the water content of the improved gas generating agent is controlled to be less than or equal to 0.3 percent, and the actual measurement value is 0.20 percent.

Example 4

4.0kg of guanidine nitrate, 5.2kg of basic copper nitrate and 300g of strontium nitrate are respectively weighed; weighing 1kg of starch solution with the solid content of 50 percent and 30g of melamine formaldehyde resin, mixing, adding the mixture into 10kg of water with the temperature of 40 ℃, uniformly stirring, carrying out spray granulation and drying to obtain particles with good fluidity, pressing into circular tablets with the diameter of 5mm and the thickness of 2mm by using a rotary tablet press under the conditions of the rotating speed of 70r/min, the filling capacity of 5mm and the pressure of 6.0kN, and drying for 4 hours in a drying oven at the temperature of 110 ℃, wherein the moisture content of the improved gas generating agent is controlled to be less than or equal to 0.3 percent, and the actual measurement value is 0.18 percent.

Example 5

4.0kg of guanidine nitrate, 5.2kg of basic copper nitrate and 300g of strontium nitrate are respectively weighed; weighing 1kg of starch solution with the solid content of 50 percent and 30g of polyamide polyurea resin, mixing, adding into 10kg of water with the temperature of 40 ℃, uniformly stirring, carrying out spray granulation and drying to obtain particles with good fluidity, pressing into round tablets with the diameter of 5mm and the thickness of 2mm by using a rotary tablet press under the conditions of the rotating speed of 70r/min, the filling capacity of 5mm and the pressure of 6.0kN, and drying for 4 hours in a drying oven at the temperature of 110 ℃, wherein the moisture content of the improved gas generating agent is controlled to be less than or equal to 0.3 percent, and the actual measurement value is 0.25 percent.

Example 6

4.0kg of guanidine nitrate, 5.2kg of basic copper nitrate and 300g of strontium nitrate are respectively weighed; weighing 1kg of starch solution with the solid content of 50 percent and 30g of polyamide polyamine epichlorohydrin resin, mixing, adding into 10kg of water with the temperature of 40 ℃, uniformly stirring, carrying out spray granulation and drying to obtain particles with good fluidity, mechanically pressing into circular tablets with the diameter of 5mm and the thickness of 2mm by using a rotary tablet press under the conditions of the rotating speed of 70r/min, the filling capacity of 5mm and the pressure of 6.0kN, and drying for 4 hours in an oven at the temperature of 110 ℃, wherein the water content of the improved gas generating agent is controlled to be less than or equal to 0.3 percent, and the actual measurement value is 0.23 percent.

Comparative example 1

4.0kg of guanidine nitrate, 5.2kg of basic copper nitrate and 300g of strontium nitrate are respectively weighed; weighing 1kg of sodium carboxymethylcellulose solution with the solid content of 50%, mixing, adding into 10kg of water with the temperature of 40 ℃, uniformly stirring, carrying out spray granulation and drying to obtain granules with good fluidity, pressing into circular tablets with the diameter of 5mm and the thickness of 2mm by using a rotary tablet press at the rotating speed of 50r/min, the filling impact of 5.5mm and the pressure of 6.0kN, and drying for 4 hours in an oven at the temperature of 110 ℃, wherein the water content of the improved gas generant is controlled to be less than or equal to 0.3%, and the actual measurement value is 0.23%.

Comparative example 2

4.0kg of guanidine nitrate, 5.2kg of basic copper nitrate and 300g of strontium nitrate are respectively weighed; weighing 1kg of starch solution with solid content of 50%, mixing, adding into 10kg of water with temperature of 40 ℃, stirring uniformly, performing spray granulation and drying to obtain granules with good fluidity, pressing into round tablets with diameter of 5mm and thickness of 2mm by using a rotary tablet press at the rotating speed of 50r/min, filling amount of 5.5mm and pressure of 6.0kN, and drying in an oven at 110 ℃ for 4 hours, wherein the water content of the improved gas generating agent is controlled to be less than or equal to 0.3%, and the actual measurement value is 0.19%.

100g of each of the gas generants of examples 1 to 6 and comparative examples 1 to 2 was weighed, laid out in a pan, placed in a high humidity cabinet having a temperature of 23 ℃ C. + -. 2 ℃ and a relative humidity of 70% + -. 5%, left for 12 hours, and subjected to moisture test using a rapid moisture meter. See table 1.

TABLE 1 moisture content data after moisture absorption of tablets

Examples	Example 1	Example 2	Example 3	Comparative example 1
					Water content%	2.3	1.9	2.5	4.8
Practice ofExample (b)	Example 4	Example 5	Example 6	Comparative example 2
					Water content%	2.7	2.3	2.6	5.2

As seen from the above data of tablets after completion of the moisture absorption test, for the formulation to which the binder was added, the water repellency of the gas generant was greatly improved after the addition of the corresponding curing agent, and the moisture absorption was about 50% of that of the comparative example. The principle of improving the hygroscopicity is that the polymer binder forms a water-repellent polymer network on the outer surface and the inner part of the gas generating agent. The gas generating agent with strong water repellency can improve the environmental adaptability of the gas generating agent, keep the performance not to be reduced in the long-term use process and reduce the cost for controlling the production environment.

TABLE 2 tabletting Condition and yield data

Examples	Example 1	Example 2	Example 3	Comparative example 1
					Tabletting condition and yield	Good, 99.9%	Good, 99.9%	Good, 99.9%	General, 96.9%
Examples	Example 4	Example 5	Example 6	Comparative example 2
					Tabletting condition and yield	Good, 99.9%	Good, 99.9%	Good, 99.9%	Generally, 93.6 percent

According to the tabletting condition and the finished product rate data, for the formula added with the adhesive, the tabletting finished product rate is obviously improved after the corresponding curing agent is added, and the improvement of the production efficiency is facilitated.

The invention has been described in detail with reference to specific embodiments and illustrative examples, but the description is not intended to be construed in a limiting sense. Those skilled in the art will appreciate that various equivalent substitutions, modifications or improvements may be made to the technical solution of the present invention and its embodiments without departing from the spirit and scope of the present invention, which fall within the scope of the present invention. The scope of the invention is defined by the appended claims.

Those skilled in the art will appreciate that those matters not described in detail in the present specification are not particularly limited to the specific examples described herein.

Claims (9)

1. The gas generating agent with excellent water repellency is characterized by comprising the following components in parts by mass: 25% -60% of organic fuel; 37% -59% of an oxidant; 1 to 10 percent of adhesive added with water repellent agent, the total mass percent of each component is 100 percent, and the dosage is calculated by the solid content of the effective component.

2. The gas generating agent having excellent water repellency according to claim 1, wherein the binder is at least one selected from the group consisting of cellulose, hemicellulose, methyl cellulose, salts of methyl cellulose, cellulose derivatives and salts such as cellulose acetate, polyvinyl alcohol, guar gum, starch, modified starch, styrene acetate white latex, styrene butadiene latex, acrylonitrile butadiene latex, soybean protein, acrylic emulsion, styrene acrylic copolymer emulsion, various emulsion modified by copolymerization with acrylic acid, various emulsion modified by copolymerization with styrene, and the like.

3. The gas generating agent excellent in water repellency according to claim 1, characterized in that the water repellent agent is at least one selected from urea-formaldehyde resin, melamine-formaldehyde resin, polyamide polyurea resin, and polyamide polyamine epichlorohydrin resin.

4. The gas generating agent excellent in water repellency according to claim 1, characterized in that the amount of the water repellent agent is 1% to 8% in terms of solid content of the binder.

5. The gas generating agent excellent in water repellency according to claim 1, characterized in that the organic fuel is at least one selected from the group consisting of 5-aminotetrazole, guanidine nitrate or nitroguanidine, and derivatives thereof.

6. The gas generating agent excellent in water repellency according to claim 1, characterized in that the oxidizing agent comprises a main oxidizing agent, and the main oxidizing agent is basic copper nitrate and strontium nitrate.

7. The gas generating agent with excellent water repellency according to claim 1, wherein the oxidant further comprises 0-5% by mass of a secondary oxidant selected from at least one of metal oxides, perchlorates, hypochlorites and nitrates.

8. A method for preparing a gas generating agent with excellent water repellency is characterized by comprising the following steps:

step 1, weighing organic fuel and oxidant according to the designed component proportion;

step 2, weighing the adhesive added with the water repellent agent according to the designed component proportion, and uniformly mixing the adhesive with the organic fuel and the oxidant;

and 3, adopting wet granulation, dry granulation or spray granulation and then pressing into tablets, or directly pressing dry powder into tablets.

9. The process for producing a gas generating agent excellent in water repellency according to claim 8, characterized in that,

for wet granulation followed by compression into tablets, the process parameters included: the rotating speed is 65-70 r/min, and the pressure is 6.0-6.5 kN;

for dry granulated and compressed tablets, the process parameters included: the rotating speed is 65-70 r/min, and the pressure is 6.0-6.5 kN;

for spray granulation followed by compression into tablets, the process parameters included: the rotating speed is 70-75 r/min, and the pressure is 6.0-6.5 kN;

for direct dry powder direct compression, the process parameters included: the rotation speed is 55-60 r/min, and the pressure is 6.0-6.5 kN.