KR100571506B1 - Heat-resistant foam rich - Google Patents

Abstract

The present invention relates to a heat-resistant foam rich, in the heat-resistant foam rich consisting of a mixture of a hardener, a reinforcing agent, a vulcanizing agent, a vulcanization accelerator, an emulsifier, a foaming agent, a foaming aid, etc., using NBR as a base material, wherein the curing agent in the mixture is a phenolic resin. The amount of this phenol resin is the same as that of NBR as the basic substance; The vulcanizing agent is sulfur and an amount corresponding to approximately half of the phenol resin addition amount is mixed; The molding process proceeds in the second stage under the conditions of 120 to 135 ° C / 800 to 1000 seconds and 160 to 190 ° C / 2700 to 3600 seconds, and the molding is 68 to 120 hours at 100 to 120 ° C after the molding and cooling processes. It is manufactured by post-treatment, and has high oil resistance and almost no change in appearance and structure even when it is immersed in high temperature fluid above 130 ℃ for a long time, and the change in weight is less than 3%. There is an advantage that can be applied.

Engine oil, heat, float, heat resistance, heat resistance

Description

Heat-resistant foam float

1 is a 50 times magnification micrograph showing the state after the primary molding process in the heat-resistant foam rich according to the present invention,

Figure 2 is a 50 times magnification micrograph showing the state after the secondary molding process in the heat-resistant foam rich according to the present invention,

Figure 3 is a 50 times magnification micrograph showing the state when not subjected to the post-treatment process in the heat-resistant foam rich according to the present invention,

Figure 4 is a 50 times magnification micrograph showing the state when the after-treatment step in the heat-resistant foam rich according to the present invention,

Figure 5 is a graph showing the weight change rate according to the temperature of the heat-resistant foam rich according to the present invention,

Figure 6 is a graph showing the volume change rate according to the temperature of the heat-resistant foam rich according to the present invention.

※ Explanation of code for main part of drawing

A: control standard

B: Molded article not subject to post-treatment in the present invention (Invention II)

C: molding after the post-treatment process in the present invention (Invention I)

The present invention relates to a heat-resistant foam rich, more specifically, to a heat-resistant foam rich little change in weight and volume during deposition in hot fluid fuel of 130 ℃ or more.

Foam rich is widely used in flow meters, liquid level controllers, automatic level sensors of various devices and machinery such as automobiles, motorcycles, agricultural machinery, ships, heaters, vaporizers, humidifiers, compressors, etc. have.

Foamed parts made of NBR (nitrile-butadiene rubber), which are produced in Korea, have a specific gravity of 0.2-0.3, excellent oil resistance, water resistance, LPG resistance, and can withstand pressures of 25㎏ / ㎠ and general gasoline and LPG automobiles. It is widely used in various flow meters. However, these foamed parts are not able to be used at high temperatures because swelling occurs when the temperature rises above 60 ° C. in a room temperature air atmosphere.

In particular, unlike the past, due to the development of automobile plating technology, when the vehicle is manufactured with foamed parts made of NBR for gasoline in advance, the paint is sometimes damaged at high temperatures of 120 ° C or higher required during the painting process. It is a drawback that the meter cannot be properly metered for general fuel gauges.In addition, when it is deposited for more than 130 ℃ for a long time, the fluid penetrates into the foam part and loses its function. It could hardly be used as rich for the level sensor of a stove and a boiler.

High-temperature foamed parts should be within 3% of the weight change rate even if they are immersed in a fluid above 130 ℃ for a long time and should not expand or loosen in appearance. Currently, domestic technology cannot produce a product that can meet these requirements. For high temperature applications such as engine oil, all depend on foreign products.

The present invention has a high oil resistance in view of the present situation in the foaming rich and foaming richly applicable to the general purpose because there is almost no change in appearance and structure and weight changes less than 3% when deposited for a long time at 130 ℃ or more The research experiment was repeated for a long time to develop.

As a result, by adjusting the content and processing conditions of the phenol resin and sulfur components in the composition components of the NBR foam rich parts, in contrast to the conventional foamed rich parts, which had a change in size due to expansion at 60 ℃, it is applied to a fluid of more than 150 ℃ In spite of the long time deposition, there is no fluid penetration, so it has been developed a flow meter that is especially useful for high flow rate meters, especially engine oil.

According to the present invention, in the heat-resistant foamed part made of a mixture of a hardener, a reinforcing agent, a vulcanizing agent, a vulcanization accelerator, an emulsifying agent, a foaming agent, a foaming aid, etc., using NBR as a base material,

The curing agent in the mixture is a phenol resin, the amount of which is equal to the amount of NBR which is a basic substance;

The vulcanizing agent is sulfur, and is characterized in that it is mixed in an amount corresponding to approximately half of the phenol resin addition amount.

In addition, the process of kneading the basic material of NBR in the form of a sheet (sheet) and adding a hardening agent, reinforcing agent, vulcanizing agent, vulcanization accelerator, emulsifier, foaming agent, foaming aid, etc. In the manufacturing method of the heat-resistant foam part which consists of a cutting process of cutting, the forming process of vulcanizing and hardening the cut dough, and the process of cooling a molded object,

In the mixing step, the curing agent is a phenol resin and the same amount as the base material NBR, the vulcanizing agent is sulfur and is added in an amount corresponding to half of the addition amount of the phenol resin;

The molding process is carried out two times under the conditions of 120 to 135 ° C / 800 to 1000 seconds and 160 to 190 ° C / 2700 to 3600 seconds, respectively;

After the molding and cooling process is characterized in that the molded product is post-treated at 100 to 120 ℃ for 68 to 120 hours.

NBR, which is a main component in the heat-resistant foam rich according to the present invention, is prepared by copolymerization of butadiene (BD) and acrylonitrile (AN) as well known and imparts polarity to the polymer by the —C≡N group of acrylonitrile. It has the function of raising the glass transition point (Tg) by having oil resistance and rubber elasticity against petroleum, so the physical properties can be adjusted according to the change of copolymerization ratio or the mixing prescription, and the content ratio of acrylonitrile (AN) is 28 The oil resistance is similar to chloroprene rubber at%, but the glass transition point is lowered and the oil resistance is very good at 48%, but the glass transition point is close to room temperature, which is not suitable for rubber use. Therefore, the content ratio of acrylonitrile (AN) is preferably about 28 to 48%.

The curing agent is added to the NBR to increase the hardness of the NBR, to improve the swelling resistance and to improve the impact resistance. Phenol resin, which is a thermosetting resin, is applied. Generally, the NBR is 1 and the entire mixture is 1 in NBR products. When the amount of phenolic resin is increased due to the interaction of the components in the optimum ratio, the wall of the cell does not become thinner at the time. It is possible to increase the content of phenol resin to the maximum without increasing the continuous bubble ratio and deteriorating properties such as oil resistance. In other words, it can be applied in the same amount as the base material NBR it is a feature in the present invention to significantly improve the heat resistance.

The blowing agent used in the present invention is DPT (N, N′- dinitroso penthylene tetramine), a light yellow fine crystalline powder that has been widely used for a long time, and urea-based preparations may be applied in small amounts to improve degradability.

In addition, as a reinforcing agent, a vulcanizing agent, an emulsifier, and a vulcanization accelerator, 25-25 weight% of carbon, 47-55 weight% of sulfur, 0.5-2.5 weight% of stearic acid, 5-12% of zinc oxide, etc. are adjusted and applied suitably within the said range. do.

The heat-resistant foam rich according to the present invention consisting of these components is first kneaded the basic material of the NBR to produce a sheet state, and the powder of the curing agent, reinforcing agent, vulcanizing agent, vulcanization accelerator, emulsifier, foaming agent, foaming aid In this case, the mixing process is very important because the physical properties of the dough are evenly distributed throughout the lot. Thereafter, the resulting sheet-like dough is cut into a suitable size, followed by a molding process of vulcanizing and curing the cut dough.

In the molding process, even if there is a slight difference in the mixing ratio of the raw materials, the properties of the final rich can be changed. In particular, if the NBR content is too high in the total components, the foaming capacity is lowered and the expansion ratio is lowered due to the gas pressure, whereas the foaming ratio is lowered. If the NBR content is too small, the cell state becomes poor, so the NBR content is important.

In the present invention, the heat-resistant foamed part has a mixing ratio of NBR content and other components of about 1: 2 to 3 or so.

The phenol resin added to stabilize the cell, to give hardness to the NBR, and to improve the swelling resistance and impact resistance is added in the same amount as the base material NBR, and sulfur added as a vulcanizing agent to approximately half of the phenolic resin. Is added in the corresponding amount.

In addition, the treatment time in the forming step also has a large influence on the properties of the rich, and proceeds for two times under the conditions of 120 to 135 ° C / 800 to 1000 seconds and 160 to 190 ° C / 2700 to 3600 seconds, respectively. If the molding temperature is too low, the foaming is not good, the foaming ratio is lowered and becomes unvulcanized, the cell size is small, the hardness and heat resistance of the rich is low, on the contrary, if the molding temperature is too high, the cell size in the rich and the cell wall is thin It loses or disappears, and it is inadequate because it shows continuous foaming phenomenon in which each cell is connected. Therefore, it is required to be processed within the above range, showing the smallest weight change rate and excellent performance.

In addition, as shown in FIG. 1, the foamed part in the intermediate stage after the first vulcanization is not foamed in part because it is not foamed a lot, but as shown in FIG. 2, the entire part is finally formed by secondary vulcanization under the above conditions. This is vulcanized to form a complete bubble. It must therefore be vulcanized and cured twice under these conditions.

And, in the case of the heat-resistant foam rich according to the present invention by heat treatment for 68 to 120 hours at 100 to 120 ℃ after cooling the molding, as shown in FIG. These reactions are slowly reacted at low temperatures, resulting in a complete foaming, resulting in an increase in cell size, hardness, and slower diffusion into the solution during deposition.

The heat-resistant foam rich according to the present invention having the above configuration will be described through the following examples, and this embodiment is only for understanding the characteristics of the present invention more easily. It is to be understood that the invention is not limited thereto and that modifications and variations are possible within the scope of the claims without departing from the scope of the invention.

Example 1

In the first and second hoppers to prepare NBR foamed parts, 28.9% by weight of powdered carbon, 3.6% by weight of DPT, 50% by weight of sulfur, 7.7% by weight of zinc oxide and 1.1 weight of L-7 as vulcanization accelerator. %, 1.5% by weight stearic acid, 2.6% by weight foaming aid and 100 parts by weight of phenolic resin were prepared in advance to prepare a uniformly well-mixed composition, respectively, the first and second in one third hopper as a control standard In the same manner as in the hopper, all the ingredients were added, but only 50% by weight of the phenol resin was added to prepare a composition.

100 parts by weight of NBR were respectively introduced into the kneaders connected to all the first, second and third hoppers respectively, and kneaded well to discharge the NBR in the sheet state, and the pre-prepared composition from each of the corresponding hoppers was added to the surface of the sheet. The mixture was sprayed on to mix evenly and uniformly so that the same effect was uniformly produced in the same lot. Each sample was cut to the same size to obtain three samples.

All three samples were treated with the same primary molding conditions, but the secondary molding conditions were treated for 2900 seconds at 170 ° C for the first and second samples, but for 2500 seconds at 200 ° C for the third control. Except for one, all three samples were treated the same to form a molding.

In the case of the first sample only, the molded product obtained after cooling was further heat treated in an oven at 110 ° C. for 72 hours.

After the obtained moldings were deposited in the same liquid fuel tank, the weight change and volume change according to temperature were tested. The results are as shown in Table 1 and Table 2.

Table 1. Weight change rate with temperature

              sample                                          Invention I (Through the post-treatment process) Invention Ⅱ (Though not undergoing post-treatment) Control standard (normal gasoline foam rich) Initial (℃) Weight (g) 3.79 3.81 3.78 60 ℃ Weight (g) 3.79 3.82 3.80 % Change 0.00 0.26 0.53 100 ℃ Weight (g) 3.82 3.85 4.05 % Change 0.79 1.05 7.14 150 ℃ Weight (g) 3.90 3.95 4.45 % Change 2.90 3.67 17.72

Table 2. Volume change rate with temperature

sample

Invention I (Through the post-treatment process) Invention Ⅱ (Though not undergoing post-treatment) Control standard (normal gasoline foam rich) Initial (℃) Weight (g) 9.76 9.78 9.79 60 ℃ Weight (g) 9.76 9.78 9.82 % Change 0.00 0.00 0.31 100 ℃ Weight (g) 9.80 9.82 10.02 % Change 0.41 0.41 2.35 150 ℃ Weight (g) 10.01 10.07 10.35 % Change 2.56 2.97 5.72

In other words, the weight (g) of the first, second and third samples was 3.79, 3.81 and 3.78 respectively, but as shown in Table 1, the weight change rate with temperature was 0.00, 0.26 and 0.53 at 60 ℃. It was 0.79, 1.05, and 7.14 at 100 ° C, and 2.90, 3.67, and 17.72 at 150 ° C, respectively, indicating that the penetration of the solution during deposition at high temperature was very high for the control standard which is usually used for gasoline. The first sample (invention I) after the post-treatment process was found to have the lowest weight change rate (see FIG. 5).

In addition, the volume change rate according to the temperature was also shown that the first sample (Invention I) after the post-treatment process as shown in Table 2 is the lowest volume change rate is optimal for high temperature (see Figure 6).

As described above, the heat-resistant foam part according to the present invention has almost no change in weight and volume even when deposited in a high temperature fluid of 150 ° C. or higher, and since the structure is not loose or expanded in appearance, it may be optimally used for high temperature applications such as engine oil.

Therefore, according to the present invention, it is possible to increase the technology of domestic foamed rich who depend on imports for engine oil at the same time, and to achieve import substitution effect and to diversify its use for liquid level measurement in all fields. It is very economical because it can be used in general and can be manufactured inexpensively because the manufacturing process is simple.

Claims (2)

In heat-resistant foamed parts made of a mixture of a hardener, a reinforcing agent, a vulcanizing agent, a vulcanization accelerator, an emulsifier, a foaming agent, a foaming aid, etc., using NBR as a base material, The curing agent in the mixture is applied in the same amount as the phenol resin and the base material NBR, and the vulcanizing agent is added in an amount corresponding to about half of the amount of the phenol resin added; The molding process proceeds in the second stage under the conditions of 120 to 135 ° C / 800 to 1000 seconds and 160 to 190 ° C / 2700 to 3600 seconds, respectively; After the molding and cooling treatment, a molded product is formed by post-treatment at 100 to 120 ° C. for 68 to 120 hours; The heat-resistant foamed part characterized in that the weight change rate is 3% or less when deposited in a high temperature fluid of 150 ° C or higher. delete

Images