JP5422113B2 - Method for producing gas generating agent - Google Patents

Description

  The present invention relates to a method for producing a gas generating agent used in a gas generator such as an airbag apparatus.

  In general, the gas generating agent supplies raw material components including a fuel and an oxidizer, and agitates and mixes in the presence of moisture, a step of drawing and cutting the mixture, and cutting the dried product. It is manufactured by a manufacturing method including a process. Cutting in this manufacturing method is performed by a cutting machine such as a rotary cutter or a guillotine cutter.

  However, in the unlikely event that a metal piece or the like is mixed into the drawn product, the metal piece may come into contact with the blade of the cutting machine to generate a spark and ignite.

JP 2001-320991 A USP 6,136,112 USP 6,165,307 USP 5,445,690

  This invention makes it a subject to provide the manufacturing method of the gas generating agent which can improve a work process, can raise work safety to a higher level, and can further improve the dimensional accuracy by cutting | disconnection.

The invention of claim 1
A first step of supplying raw material components including a fuel and an oxidant and stirring and mixing in the presence of moisture;
A second step of drawing the mixture obtained in the previous step,
A third step of cutting the molded product obtained in the previous step;
It has a fourth step of drying the cut product obtained in the previous step,
In the third step, a method for producing a gas generating agent (hereinafter referred to as “first production method”) is provided, in which the molded product is cut by water jet cutting.

  Invention of Claim 2 provides the manufacturing method of the gas generating agent of Claim 1 which has a drying process between the said 2nd process and the said 3rd process.

The invention of claim 3
A first step of supplying raw material components including a fuel and an oxidant and stirring and mixing in the presence of moisture;
A second step of drawing the mixture obtained in the previous step,
A third step of cutting the molded product obtained in the previous step by mechanical means;
A fourth step of drying the cut product obtained in the previous step;
It has a fifth step of cutting again the dried product obtained in the previous step,
In the fifth step, there is provided a method for producing a gas generating agent (hereinafter referred to as “second production method”) which is cut by water jet cutting.

The invention of claim 4
A first step of supplying raw material components including a fuel and an oxidant and stirring and mixing in the presence of moisture;
A second step of drawing the mixture obtained in the previous step,
A third step of cutting the molded product obtained in the previous step;
A fourth step of drying the cut product obtained in the previous step;
It has a fifth step of cutting again the dried product obtained in the previous step,
In the third step and the fifth step, there is provided a method for producing a gas generating agent (hereinafter referred to as “third production method”) which is cut by water jet cutting.

  By applying the production method of the present invention, work safety can be raised to a higher level, and a gas generating agent can be obtained with higher dimensional accuracy.

(1) 1st manufacturing method The 1st manufacturing method of a gas generating agent comprises the above-mentioned 1st process-4th process, and is a well-known process except the process cut by applying water jet cutting. Can be the same. In addition, before and after each of the above steps, a processing step usually performed by a person skilled in the art at the time of producing the gas generating agent can be added. In addition, in each following process, unless otherwise indicated, it can apply to both a batch type and a continuous type.

<First step>
The first step is a step of supplying two or more raw material components including a fuel and an oxidant and stirring and mixing them in the presence of moisture. In the process of the first step, the following methods can be appropriately selected as a method for supplying two or more raw material components and moisture. “Moisture” in the first step means both moisture present from the beginning in two or more raw material components and moisture supplied to the raw material.

(i) A method in which a necessary amount of water is supplied to each of two or more raw material components and then mixed;
(ii) A method in which two or more raw material components and a required amount of water are simultaneously supplied and then mixed;
(iii) A method of supplying a required amount of water while mixing two or more raw material components;
(iv) A method in which two or more kinds of raw material components are premixed and then a required amount of water is supplied and further mixed;
(v) A method of spraying and supplying a required amount of water in the above methods (i) to (iv).

  In the first step, an aqueous solution, water, water vapor, and a mixture of these two or three types can be used as the water to be supplied. Here, the aqueous solution is an aqueous solution of a soluble component in two or more raw material components, for example, a water-soluble binder.

  These aqueous solutions, water, and water vapor are preferably free of metal ions such as alkali metal ions such as Na, K and Li, alkaline earth metal ions such as Mg and Ca, and other metal ions. Water and / or distilled water is more preferred. The reason for using water or the like that does not contain metal ions is as follows. For example, when water contains Na ions as metal ions, NaOH is generated from Na ions, which may remain in the gas generant. This is because, in some cases, raw material components such as fuel are decomposed by the hydrolysis reaction, and the thermal stability of the gas generating agent itself may be lowered.

  The mixing condition of the two or more kinds of raw material components and moisture in the first step is preferably a mixing temperature of 20 to 100 ° C., more preferably 40 to 80 ° C., and a mixing time of 10 to 10 preferably in a batch type. 120 minutes, more preferably 30 to 60 minutes, and continuous case is preferably 1 to 10 minutes.

  When the production method of the present invention is carried out batchwise, in the first step, a process for volatilizing and removing a part of water can be performed while further mixing, and a part of the water is volatilized and removed after mixing is completed. You can also

  When part of such water is volatilized and removed, the water can be volatilized and removed by raising the temperature preferably from 0 to 80 ° C., more preferably from 10 to 30 ° C. than the temperature at the time of mixing. Furthermore, in order to smoothly perform the process in the post-process, when a part of the water is volatilized and removed in this way, the water content (wet base value) in the gas generating agent is preferably 10 to 30% by weight, more preferably Adjust to 15-20 wt%.

  The method of removing part of the water by volatilization is applied when two or more kinds of raw materials and water are used in a mixer in the first step and deaerated while being sucked as needed from the vent of the mixer. it can.

  In addition, when the production method of the present invention is carried out batchwise, as described above, after removing a part of the water by volatilization while mixing, a cooling treatment is added to facilitate the handling in the subsequent process (aging process). Can do. In this cooling treatment, the mixture is cooled so that the temperature of the mixture after cooling is preferably 30 to 65 ° C, more preferably 30 to 50 ° C.

  Although the cooling method is not particularly limited, when mixing of two or more kinds of raw materials and moisture in the first step is performed with a mixer, a method of appropriately combining operations of reversing the stirring direction and / or normal rotation can be applied. Here, “reverse rotation” or “forward rotation” means that the stirring direction (rotation direction) is different when there is one stirrer, but “reverse rotation” is adjacent to two when there are two agitators. This means that one of the two agitators (left side) is rotated clockwise and the other (right side) is rotated counterclockwise. “Forward” means that the left agitator is rotated counterclockwise. , Meaning that the right agitator is rotated clockwise.

  When the production method of the present invention is carried out batchwise, temperature unevenness and moisture unevenness are prevented from occurring in the mixture between the first step and the second step, and the temperature is adjusted to a temperature at which it is easy to draw and mold. An aging step of the mixture can be provided.

  The aging treatment is preferably carried out by holding at 30 to 50 ° C., more preferably 35 to 45 ° C., preferably 8 hours or more, more preferably 16 hours or more.

  The aging treatment can be performed in the mixer used in the first step, or can be performed by transferring the mixture to another container that can hold the mixture under predetermined conditions.

  The components of the gas generating agent such as fuel and oxidant used in this step are not particularly limited, and known ones can be used. For example, the fuel, oxidant and additive described in Patent Document 1 are used. Can do.

<Second step>
The second step is a step in which the mixture of two or more raw material components obtained in the first step and moisture is drawn. In addition, when a batch type is applied, the mixture that has undergone the first step or the subsequent aging step is drawn by a drawing machine.

  The drawing method is not particularly limited, and a method of forming in one step and a method of dividing into two or more steps including preliminary forming can be applied. When it is performed in one stage, the molding pressure is preferably 70 MPa or less, more preferably 60 MPa or less, and when it is performed in two stages, the molding pressure is preferably 70 MPa or less, more preferably 60 MPa or less, and further molding is performed. The molding is performed at a pressure of preferably 70 MPa or less, more preferably 60 MPa or less.

<Additional process>
A drying step can be provided as necessary between the second step and the next third step. This drying step is a step for facilitating water jet cutting in the next step. For this reason, it may be dry to such an extent that the surface of the molded product obtained in the previous step is dried, and may be milder than the degree of drying in the fourth step.

  In this step, for example, drying conditions comparable to the preliminary drying in the case of two-stage drying in the fourth step can be applied.

<Third step>
The third step is a step of cutting the molded product obtained in the previous step or a dried product thereof. In the cutting process, the sheet is cut into dimensions that meet the required standards by water jet cutting.

  Water jet cutting uses a known water jet cutting device and jets jet water from a nozzle having a diameter of about 0.1 to 1.5 mm with a pressure of about 50 to 400 MPa and a flow rate of about 0.5 to 25 liters / minute. You can apply the method you want. In this step, no abrasive is used in combination.

  The distance between the nozzle and the molded product to be cut or its dried product is preferably about 1 to 10 mm. The cutting speed is preferably 0.5 to 10 m / min.

  By applying water jet cutting as described above in this process, it can be cut with high dimensional accuracy without deformation of the cut surface, etc., and even if fine cut pieces are produced, there is no danger of ignition and it is safe Can be recovered. In addition, when the water jet cutting is applied, there is almost no water wetting of the cut surface, so that the drying process of the next process can be made to the same level as when cutting by mechanical means.

<4th process>
In the fourth step, the molded product cut in the third step is dried. In addition, a drying process is performed in a dryer in any case of a batch type and a continuous type.

  The drying treatment is performed so that the amount of water in the gas generating agent is preferably 0.5% by weight or less, more preferably 0.3% by weight or less.

  The drying method is not particularly limited, and a method of drying in one step and a method of dividing into two or more steps including preliminary drying can be applied. When it is performed in one stage, it is preferably 80 to 120 ° C., more preferably 90 to 110 ° C., and when it is performed in two stages, it is preferably 20 to 40 ° C., more preferably 25 to 35 ° C. after preliminary drying. Further, it is preferably dried at 80 to 120 ° C, more preferably 90 to 110 ° C.

  After the fourth step, it is possible to add a step of classifying the gas generating agent so as to have the same size by sieving. By applying water jet cutting in the third step, the target object can be obtained with higher accuracy, so that classification processing is facilitated.

  In the production method of the present invention, in the case of a batch type, the above-described processes can be performed by, for example, a combination of a mixer, a container for aging, a drawing machine, a water jet cutting device, and a dryer. In the case of a continuous type, it can be carried out by a combination of a twin-screw kneading extruder and a water jet cutting device combined so that the treatment can be performed continuously and a dryer.

(2) Second and third production methods The second and third production methods of the gas generant include the first to fifth steps described above, and cut by applying water jet cutting. Except for the steps, the steps can be the same as known steps. In addition, before and after each of the above steps, a processing step usually performed by a person skilled in the art at the time of producing the gas generating agent can be added. In addition, in each following process, unless otherwise indicated, it can apply to both a batch type and a continuous type.

<First step to third step>
The first step and the second step are the same as the first manufacturing method. In the third step, the molded product obtained in the second step is cut by mechanical means or water jet cutting. In addition, when cut | disconnecting by a mechanical means, it can prevent that a spark generate | occur | produces even if a metal piece is mixed by raising the moisture state of a molded product a little.

  In the second manufacturing method, the cutting in the third step is performed to a size that meets the required standard by a cutting machine (such as a rotary cutter or a guillotine cutter) by mechanical means or a cutting machine connected to a drawing machine. Disconnect.

  In the third manufacturing method, the cutting in the third step is performed by water jet cutting to a size that meets the required standard.

<4th process>
The fourth step is a step of drying the cut product obtained in the third step. Drying in this step can be performed in the same manner as in the fourth step of the first manufacturing method.

<5th process>
The fifth step is a step of cutting the dried product obtained in the fourth step again by water jet cutting. This step is performed for the purpose of improving the dimensional accuracy of the material cut in the third step and dried in the fourth step (for the purpose of finely adjusting the size). In addition, when water jet cutting is applied, there is almost no water wetting on the cut surface, so that it is not necessary to provide a drying step after this step, but it may be dried again.

  The cutting process in this step facilitates fine adjustment of the amount required to obtain a predetermined operating pressure with the gas generating agent when used in a gas generator for an air bag. Further, by applying water jet cutting, fine cut pieces can be safely recovered without risk of ignition.

Example 1
<First step>
Production raw materials were 40.7% by mass of guanidine nitrate, 49.3% by mass of basic copper nitrate, 5.0% by mass of sodium carboxymethylcellulose, 5.0% by mass of aluminum hydroxide, and 100 parts by mass of each of the above components. On the other hand, 14.7 parts by mass of ion-exchanged water (electric conductivity 1 μS / cm) was added to a kneader and then mixed at a temperature of 60 ° C. for 60 minutes.

  Thereafter, the temperature of the mixture was lowered to 45 ° C. while stirring in a kneader. Next, the mixture was taken out from the kneading machine, transferred to an aging machine capable of temperature control, and kept at 40 ° C. for 15 hours for aging.

<Second step>
Next, the mixture after aging was supplied to a drawing machine and molded at a molding pressure of 35 MPa to obtain a strand having a single hole.

<Additional process>
A hot air of 110 ° C. was blown onto the strand to dry the surface.

<Third step>
The strand after drying in the previous step was subjected to water jet cutting using a water jet cutting device (manufactured by Sugino Machine Co., Ltd.) having the following specifications to obtain a single-hole cylindrical gas generating agent.
Nozzle diameter: 0.2mm
Distance between nozzle and cutting object: 5mm
Jet water pressure: 150MPa
Jet water flow rate: 1.2 l / min Cutting speed: 3 m / min

<4th process>
Thereafter, the gas generating agent is put in a dryer, preliminarily dried by holding at 30 ° C., and further dried at 80 ° C. to reduce the water content to 0.3% by weight or less, and then sieved to obtain a final product. (Single-hole cylindrical gas generating agent having an outer diameter of 25 mm, an inner diameter of 6 mm, and a length of 100 mm) was obtained.

  100 obtained gas generating agents were arbitrarily sampled, and their dimensions and mass were measured. As a result, the length error was ± 0.5% or less, and the mass error was ± 0.5% or less.

Claims (3)

A first step of supplying raw material components including a fuel and an oxidant and stirring and mixing in the presence of moisture;
A second step of drawing the mixture obtained in the previous step,
A third step of cutting the molded product obtained in the previous step;
It has the 4th process including the process of drying at 80-120 ° C the cut thing obtained at the previous process,
Between the second step and the third step, the method has a drying step of drying the surface of the molded product obtained in the second step at 20 to 40 ° C.,
A method for producing a gas generating agent, wherein the molded product is cut by water jet cutting in the third step. A first step of supplying raw material components including a fuel and an oxidant and stirring and mixing in the presence of moisture;
A second step of drawing the mixture obtained in the previous step,
A third step of cutting the molded product obtained in the previous step by mechanical means;
A fourth step including a step of drying the cut product obtained in the previous step at 80 to 120 ° C . ;
It has a fifth step of cutting again the dried product obtained in the previous step,
A method for producing a gas generating agent, wherein in the fifth step, after cutting by water jet cutting for the purpose of increasing dimensional accuracy, no drying treatment is performed thereafter . A first step of supplying raw material components including a fuel and an oxidant and stirring and mixing in the presence of moisture;
A second step of drawing the mixture obtained in the previous step,
A third step of cutting the molded product obtained in the previous step by water jet cutting ;
A fourth step including a step of drying the cut product obtained in the previous step at 80 to 120 ° C . ;
It has a fifth step of cutting the dried product obtained in the previous step again by water jet cutting ,
In the fifth step, the gas generating agent is produced by cutting by water jet cutting for the purpose of improving the dimensional accuracy, and thereafter performing no drying treatment .