JP4677122B2 - Carbonized foam and method for producing the same - Google Patents

Description

【００３４】
(結果)
外部加熱または内部加熱だけにより乾燥を施した場合、前記被覆発泡体の段階で、図３に示す如く、被覆層を形成するフェノール樹脂の黄色の濃淡がはっきりと確認され、全体に均一な黄色となっている実験例(図３(ａ)参照)に較べ、該外部加熱の場合、外側の黄色が濃く(図３(ｂ)参照)、また該内部加熱の場合、反対に内側の黄色が濃く(図３(ｃ)参照)、すなわち加熱により先に乾燥がなされる側にフェノール樹脂が移動していることが確認された。また炭化を施して得られる炭素化フォームのついても、図４に示す如く、実験例に係る炭素化フォームでは均一な骨格が形成されている(図４(ａ)参照)ことが確認されているのに対して、比較例に係る炭素化フォームでは骨格間に膜の生成が確認された(図４(ｂ)参照)。図４(ｂ)に係るＳＥＭ写真は比較例１に係る炭素化フォームのものであるが、比較例１および比較例２では大きな差が確認されなかったため、比較例１に係るＳＥＭ写真だけを採用した。なお図４に係るＳＥＭ写真において、夫々の骨格間隙間の大きさの差違は前述したプレス倍率の違いにより生じたものである。
【００３５】
また強度についても、前述の骨格の太さを反映し、比較例１および比較例２に係る炭素化フォームが接触するだけで欠損が生じたり、触感が不良であったりするのに対して、実験例に係る炭素化フォームは問題を生じなかった。更に加熱時間についても、実験例に係る炭素化フォームは、比較例１および比較例２に係る炭素化フォームが夫々３０分間および４分間の乾燥時間で充分な乾燥を達成し得なかったのに対して、４分間の乾燥時間で充分な乾燥を達成した。
【００３６】
【発明の効果】
以上説明した如く、本発明に係る炭素化フォームおよびその製造方法によれば、メラミン発泡体の基材上に付与される所要の樹脂の乾燥を、熱風乾燥による外部加熱およびマイクロ波加熱または高周波加熱による内部加熱で同時に実施することで、該所要の樹脂の不均一な乾燥を回避し、これにより均質な被膜層を形成し、これにより気泡径が均一かつ強い機械的強度を有すると共に、圧力損失を損なうことがない炭素化フォームを製造し得る。また乾燥に必要とされる時間を短縮し、製造コストを低減する効果も期待できる。
【図面の簡単な説明】
【図１】本発明の好適な実施例に係る炭素化フォームを示す内部の構造図である。
【図２】実施例に係る炭素化フォームを製造する工程を示すフローチャート図である。
【図３】実験に係る実験例と、比較例とから得られる被覆発泡体を切断して内部の色の状態(基材に付与されたフェノール樹脂の厚さ)を表す概略断面図である。
【図４】実験に係る実験例と、比較例１とから得られる炭素化フォームの骨格の様子および構造を夫々示す走査型電子顕微鏡写真である。
【図５】基材上に樹脂を付与した後、不均一な加熱を施して該加熱による温度差が大きく、加熱境界を挟んで乾燥して被膜層となった部位Ａと、乾燥が完了せず樹脂が存在する部位Ｂとが併存する際の該樹脂の動きを示す概略図である。
【符号の説明】
１２ 基材
１４ 被覆層
１６ 被覆発泡体[0001]
BACKGROUND OF THE INVENTION
The present invention considers a process of drying a thermosetting resin applied to the inner and outer surfaces of a foam made of melamine resin, so that a carbonized foam having a uniform coating layer formed thereon, And a method of manufacturing.
[0002]
[Prior art]
In general, a so-called carbonized foam in which the constituent element is only carbon is suitably used as a filter that can exhibit high heat resistance or chemical resistance.
[0003]
As the carbonized foam, a resin foam in which the foam diameter of the foam can be controlled depending on the intended use is generally used. However, the resin foam has a low carbonization yield, that is, a carbonization rate, and thus has disadvantages such as shrinkage due to heating. In order to eliminate this defect, as described in JP-A-6-32677, the resin foam is impregnated with a required resin, thereby achieving shape reinforcement during carbonization of the resin foam, and thereby the shrinkage. A method for avoiding this has been proposed.
[0004]
This carbonized foam is produced by impregnating a resin foam such as a urethane resin, a melamine resin, an epoxy resin, a polyvinyl chloride resin, or a phenol resin by a usual method in a required resin foam to be a base material and heating it. After the treatment is applied and the resin is dried, the carbonization treatment is performed. As a method for drying various resins impregnated in the resin foam, a conventionally known method such as so-called external heating using a hot air furnace or so-called internal heating using microwave heating or the like can be employed.
[0005]
[Problems to be Solved by the Invention]
However, when a melamine foam made from a melamine resin capable of forming a fine skeleton is used as a material of the base material, the following points are pointed out as problems when the above-described drying method is used. That is, taking the external heating method as an example, when drying is performed by external heating, drying is sequentially started from the outer surface of the base material 12 impregnated with the required resin, as shown in FIG. The impregnated resin in an undried state is gradually dried over time. At this time, the portion between the dry portion (A) that is dried by heating and the undried portion (B) that is not heated is used as a heating boundary (see FIG. 5B), and the undried portion (B) is being dried. The undried resin moves onto the coating layer 14 in the dry state (A), and as a result, the coating thickness of the coating layer 14 is different between the inside and the outside. Due to the difference in coating thickness, the carbonized foam finally obtained varies in cell diameter and skeleton thickness, that is, mechanical strength, so that the uniform carbonized foam cannot be obtained.
[0006]
Further, in some cases, a film is formed between the skeletons of the base material 12, and the small pressure loss that is one of the characteristics of the base material 12 is impaired, and the strength of the skeleton coating layer does not reach the assumed thickness. There is also a fear that will decrease. This phenomenon also occurs when the internal heating method is employed. In this case, since the drying proceeds from the inside, the bubble diameter is smaller and the mechanical strength is larger on the inner side, whereas the bubble diameter is larger on the outer side. The carbonized foam is large and has low mechanical strength.
[0007]
It is inferred that the unevenness of the film thickness inside and outside due to this drying method is caused by the following mechanism. That is, as described above, the melamine foam used as the base material 12 has a very thin skeleton, so that the surface of the skeleton serves as a capillary in the dried portion (A), and the other portion (B) is not dried. The state, in other words, the liquid resin moves due to the capillary action of the capillaries (see FIG. 5C).
[0008]
OBJECT OF THE INVENTION
In view of the disadvantages inherent in the above-described prior art carbonized foam and the method for producing the same, the present invention has been proposed to suitably solve this problem, and the inside and outside of the melamine foam as a base material is proposed. As a drying method for forming a coating layer by applying the required resin to the surface and drying the required resin, the required resin is uniformly dried by using both external heating and internal heating. An object of the present invention is to provide a homogeneous carbonized foam having no variation in cell diameter and mechanical strength depending on the part, and a method for producing the same.
[0009]
[Means for Solving the Problems]
In order to overcome the above problems and achieve the intended purpose, the carbonized foam according to the present invention is:
A coated foam consisting of a base material made of a melamine resin foam and a desired resin coating layer applied to the inner and outer surfaces of the base material and dried is heated and carbonized by heating in an oxygen-free atmosphere. Carbonized foam,
The coating layer includes an external heating by hot air Drying the desired resin, it is carried out inside the heating and at the same time by microwave heating or radio frequency heating, that the whole is dried uniformly, and became homogeneous Features.
[0010]
In order to overcome the above-mentioned problems and achieve the intended purpose, a method for producing a carbonized foam according to another invention of the present application,
Prepare a base material in which the foam of melamine resin is molded into the required shape,
By providing and drying the required resin on the inner and outer surfaces of the base material as a whole, a coated foam in which a coating layer is formed on the entire inner and outer surfaces,
A method for producing a carbonized foam in which the coated foam is heated and carbonized in an oxygen-free atmosphere,
And external heating by Neppuinui 燥, drying the desired resin by simultaneously implementing the internal heating by microwave heating or radio frequency heating, thereby to ensure the uniform drying and homogeneity of the coating layer It is characterized by that.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Next, the carbonized foam and the method for producing the same according to the present invention will be described below with reference to the accompanying drawings by way of preferred examples. The inventor of the present application provides a base material made of a foam made from a melamine resin (hereinafter referred to as a melamine foam), external heating and heating when applying and drying a predetermined resin. By adopting a method that uses internal heating together, the carbonized foam skeleton obtained by carbonizing by heat treatment under an oxygen-free atmosphere (described later) becomes uniform, pore diameter, mechanical strength, etc. It has been found that the physical properties of are uniform. The “oxygen-free atmosphere” as used in the present invention is, for example, an atmosphere in which an inert gas atmosphere such as argon gas or nitrogen gas, a reducing atmosphere, or oxygen is present, and combustion is not accelerated by heating and a carbide is obtained. Say the atmosphere.
[0012]
As shown in FIG. 1, a coated foam 16 on which a carbonized foam 10 according to a preferred embodiment of the present invention is based includes a melamine foam base 12 and a required inner and outer surface of the base 12, that is, the It is comprised from the coating layer 14 which consists of required resin which coat | covers the inner surface and outer surface of the frame | skeleton which forms a foam. The carbonized foam 10 is obtained by carbonizing the coated foam 16 by performing a heat treatment in an oxygen-free atmosphere.
[0013]
Moreover, the manufacturing method of the carbonized foam 10 which concerns on an Example consists of base material preparation process S1, coating layer formation process S2, coating layer drying process S3, carbonization process S4, and finishing process S5, as shown in FIG. Further, by performing a hot pressing step S6 in which a hot pressing is performed at a predetermined magnification in a heated state between the coating layer drying step S3 and the carbonization step S4, the cell diameter of the carbonized foam finally obtained is set to It can be controlled to an arbitrary diameter equal to or smaller than the bubble diameter of the material 12.
[0014]
Melamine resin is adopted as a raw material of the base material 12 produced in the base material production step S1, but the base material 12 obtained by adopting the melamine resin has (1) a very thin skeleton. There is a feature that the pressure loss is small, and (2) the film is not formed on the surface of the skeleton when heated, and carbonization is possible while maintaining the communication state of bubbles, that is, the degree of communication is not lowered.
[0015]
Specifically, the foaming / curing in the substrate manufacturing step S1 is performed by free rise, so-called slab molding, or by injecting a known melamine foam raw material into a required mold, and sealing or heating with a clamp or the like. A method of exothermic, foaming and curing the raw material by a conventionally known appropriate means such as irradiation of the above is employed.
[0016]
As the substrate 12, a porous melamine foam obtained by foaming melamine resin as a raw material is used. The melamine foam is obtained by blending and sufficiently mixing formaldehyde and additives such as a foaming agent, a catalyst and an emulsifier with melamine as a main raw material, and curing the foamed product after foam molding. In addition, a commercially available melamine foam can be adopted as the base material 12 as long as it satisfies a numerical value sufficient to be used in physical properties such as a bubble ratio. In this case, the base material manufacturing step S1 is omitted.
[0017]
Next, the coating layer forming step S2 to be performed is a step of forming the coating layer 14 on the inner and outer surfaces of the base material 12 produced in the base material production step S1, that is, the skeleton. Specifically, it is formed by applying a required resin by a predetermined method.
[0018]
As a specific method for applying the required resin, any conventionally known method such as impregnation, spray coating, roll coating or flow coating can be employed. Prior to application, pre-treatment such as diluting the resin may be applied to improve the application. In particular, impregnation that can be uniformly applied to the inner and outer surfaces of the substrate 12 and whose basis weight can be easily controlled is preferable.
[0019]
The coating layer 14 covers the inner and outer surfaces of the base material 12 to express the following actions and improve / change physical properties. (1) and (2) are contents related to the coated foam 16 before carbonization by heat, and (3) and (4) are contents related to the finally obtained carbonized foam.
(1) The coated foam 16 can be formed into a desired cell diameter by subjecting the coated foam 16 to a later-described hot press. At this time, the substrate 12 made of melamine foam alone is restored to its original size and shape after the hot press. Resulting in. Therefore, it is possible to maintain the shape after the heat pressing by applying the coating layer 14 and setting the processing temperature at the time of hot pressing to be equal to or higher than the thermosetting temperature of a thermosetting resin (described later) forming the coating layer 14. To. It should be noted that the smaller the restoration rate indicating the degree of restoration at this time, the better. However, it is empirically known that there is no significant effect if it is about 3% or less.
(2) The substrate 12 is a melamine foam made of melamine resin as a raw material, and the foam is greatly shrunk by heating at the time of carbonization, that is, has a large thermal shrinkage rate. It is very difficult to design the shape when the molded foam 10 is produced. Therefore, the coating layer 14 is provided to suppress thermal shrinkage due to heating during carbonization. If the shrinkage rate indicating the degree of heat shrinkage is too large, the shape design becomes difficult as described above, and if it is too small, mechanical distortion occurs in the base material 12 that should be shrunk, so about 30 to 50%. It is preferable to set in the range.
(3) The internal structure of the substrate 12 is composed of a very thin skeleton, and the mechanical strength is poor and the substrate 12 is easily damaged. Therefore, the coating layer 14 is applied to reinforce the skeleton and improve the mechanical strength.
(4) Since the coating layer 14 is applied to the skeleton surface of the substrate 12, the bubble diameter of the substrate 12 is further reduced.
That is, (1) to (3) have the effect of eliminating the disadvantages that are the reverse of the advantages of the melamine foam, which is the material of the substrate 12 described above.
[0020]
As the material forming the coating layer 14, it is necessary to fulfill the above-described action.
(A) The base material 12 can be in a liquid state so that it can be applied to the inner and outer surfaces of the base material 12 in a temperature range where heat shrinkage or the like does not occur.
(B) It is equivalent that the thermal contraction rate is smaller than that of the melamine foam which is the material of the substrate 12.
(C) When to arbitrarily control the bubble size by performing heat up less which will be described later, said base 12 causes the thermally cured at a temperature range that does not cause thermal shrinkage, i.e. a resin having a thermosetting temperature.
It is necessary to achieve such a condition. As the resin having both of these conditions, a thermosetting resin such as a phenol resin or a melamine resin is suitable.
[0021]
Then, the predetermined resin applied on the substrate 12 in the next coating layer drying step S3 is dried at a temperature at which the resin can be dried. If this drying is not performed, carbonization in the carbonization step S4, which will be described later, is not performed uniformly, or when the hot press step S6 is performed, the coating layer 14 formed from a resin is used in a press machine or the like that performs the hot press. Care must be taken because it may adhere to the press surface.
[0022]
As a means for carrying out the present coating layer drying step S3, the coated foam 16 obtained through the previous steps is uniformly heated so as to keep the temperature difference depending on the region below a certain level, for example, by a hot air dryer or the like. Examples include a method in which external heating and internal heating by microwave heating or high-frequency heating are performed simultaneously.
[0023]
If the temperature difference by the site | part mentioned above is less than 10 degreeC, the movement by the capillary phenomenon of resin by this temperature difference can be suppressed. When the temperature difference exceeds 10 ° C., the heating progress is small due to the higher temperature, that is, the temperature is constant due to the phase change (from fluid to solid) of the resin at the higher temperature. On the other hand, the phase change of the resin at the low temperature portion is not started, and the fluid state resin and the solid state resin coexist through the two portions. Under this condition, resin movement occurs due to capillary action, resulting in inhomogeneous internal structure.
[0024]
By the base material production step S1, the coating layer forming step S2, and the coating layer drying step S3 applied so far, the coated foam 16 that is a base for producing the carbonized foam 10 can be obtained from the base material 12. .
[0025]
The carbonization step S4 is a step in which the coated foam 16 that has been pressed at a predetermined magnification is heated to about 1,000 ° C. in an oxygen-free atmosphere such as argon gas to be carbonized. Although there is no restriction | limiting in particular about heating temperature, The implementation in the temperature range below 3,000 degreeC is suitable from the point of sublimation suppression of carbon, manufacturing cost, etc. Moreover, if it is in this temperature range, crystallization of the said carbon will be accelerated | stimulated, so that higher mechanical strength can be anticipated as a result.
[0026]
In the finishing step S5 to be finally performed, the carbonized foam 10 is subjected to polishing into a predetermined shape and a predetermined inspection, and the carbonized foam as a final product is obtained through this step S5. 10 is completed.
[0027]
The carbonized foam of the present invention can be used as a foam as it is. In addition to this, for example, a filter base material that imparts a predetermined function, and a catalyst carrier that has high-temperature heat resistance and chemical resistance that imparts a predetermined catalyst. Etc. can also be suitably used.
[0028]
Further, for the purpose of controlling the cell diameter of the finally obtained carbonized foam to an arbitrary diameter equal to or less than the cell diameter of the base material 12, the heating state is changed between the coating layer drying step S3 and the carbonization step S4. In step S6, the hot pressing step S6 may be performed in which the hot pressing is performed at a predetermined magnification. This hot pressing step S6 is a step of pressing at a predetermined magnification while being applied to the coated foam 16. The bubble diameter changes with the press magnification. Basically, the bubble diameter is reduced to half when the press magnification is 2 times, and is compressed to about 1/10 when the press magnification is 10. The above-mentioned press is basically applied in a direction that shrinks the height direction of the foam, although depending on the manufacturing process, the shrinkage of the bubble diameter also appears remarkably in that direction, and is large in a direction unrelated to the press direction. There is no contraction.
[0029]
When performing this heat press process S6, it is necessary to suppress the restoration rate after the press of the base material 12 as the resin, but there is no problem as long as it is a thermosetting resin such as the above-described phenol resin or melamine resin.
[0030]
Moreover, when implementing this heat press process S6, the drying temperature in the said coating layer drying process S3 is the thermosetting resin of the said thermosetting resin which forms the said coating layer 14 so that the thermosetting resin used as the said resin may not harden | cure. It is necessary to set it below the thermosetting temperature. This is because if the drying is performed at a temperature higher than this temperature, the coating layer 14 formed from the thermosetting resin is completely cured and destroyed during the pressing in the hot pressing step S6.
[0031]
[Experimental example]
Although the manufacturing method of the carbonized foam according to the example and the physical properties resulting from the thickness of the skeleton of the carbonized foam obtained by this method, that is, an experimental example for evaluation of elasticity, mechanical strength, etc. are shown, The carbonized foam and the manufacturing method thereof according to the present invention are not limited to this experimental example.
[0032]
Basically, a commercially available melamine foam (general-purpose melamine foam (made by BASF; dimensions 15 × 15 × 2 cm)) is used as a base material, and a phenol resin (trade name PE-201-) as a thermosetting resin is used for this. L; manufactured by Dainippon Ink & Chemicals, Inc.) was applied so that the dry weight per unit area was 0.012 g / cm ³ . And about an experimental example, the comparative example 1, and the comparative example 2, it dried according to the method of Table 1, performed about 10 times press about an experimental example, and performed 2 times press about each comparative example, and after temperature in argon atmosphere, Carbonized foams were obtained by carbonization at 1,000 ° C. for 2 hours. And about the said experimental example and the comparative example 1 and the comparative example 2, the temperature of the upper surface, the lower surface, and an inside, the time required for drying, and the intensity | strength by direct contacts, such as handling, were measured or confirmed. Further, the skeleton of each of the obtained coated foam and carbonized foam was cut at a substantially center line, and the cut cross section was visually observed (color tone of the phenol resin provided) and a scanning electron microscope (hereinafter referred to as SEM). (For the example, the part having a typical structure because the whole is homogeneous, and for the comparative example, the portions where the color tone is lightened by the movement of the resin due to capillary action were respectively taken). The contents of each method used as the drying means are as follows.
Experimental Example (External Heating and Internal Heating: Drying is performed simultaneously for 4 minutes by a hot air dryer under the condition of a temperature of 100 ° C. and microwave irradiation under the condition of an output of 1 kw.
Comparative Example 1 (external heating): Performed by using a hot air dryer under conditions of a temperature of 100 ° C. for 30 minutes.
Comparative Example 2 (Internal heating): Performed by irradiating microwaves under conditions of an output of 1 kw for 4 minutes.
[0033]
[Table 1]

[0034]
(result)
When drying is performed only by external heating or internal heating, the shade of yellow color of the phenol resin forming the coating layer is clearly confirmed at the stage of the coated foam, as shown in FIG. Compared to the experimental example (see FIG. 3 (a)), in the case of the external heating, the outside yellow is dark (see FIG. 3 (b)), and in the case of the internal heating, the inside yellow is dark. (See FIG. 3 (c)), that is, it was confirmed that the phenol resin had moved to the side that was previously dried by heating. Further, as for the carbonized foam obtained by carbonization, as shown in FIG. 4, it is confirmed that a uniform skeleton is formed in the carbonized foam according to the experimental example (see FIG. 4 (a)). On the other hand, in the carbonized foam according to the comparative example, formation of a film between the skeletons was confirmed (see FIG. 4B). Although the SEM photograph concerning FIG.4 (b) is a thing of the carbonization foam concerning the comparative example 1, since the big difference was not confirmed by the comparative example 1 and the comparative example 2, only the SEM photograph concerning the comparative example 1 is employ | adopted. did. In the SEM photograph according to FIG. 4, the difference in size between the skeletal gaps is caused by the difference in the press magnification described above.
[0035]
The strength also reflects the thickness of the skeleton, and the carbonized foams according to Comparative Example 1 and Comparative Example 2 are contacted with each other to cause defects or have poor tactile sensations. The carbonized foam according to the example did not cause a problem. Further, regarding the heating time, the carbonized foam according to the experimental example could not achieve sufficient drying with the drying times of 30 minutes and 4 minutes, respectively, according to the comparative examples 1 and 2. Thus, sufficient drying was achieved with a drying time of 4 minutes.
[0036]
【The invention's effect】
As mentioned above has been described, according to the carbonization foams and a manufacturing method thereof according to the present invention, the drying of the required resin applied on the substrate of the melamine foam, or external heating and microwave heating by Neppuinui 燥 By simultaneously carrying out internal heating by high frequency heating , avoiding uneven drying of the required resin, thereby forming a uniform coating layer, thereby having a uniform and strong mechanical strength of the bubble diameter, Carbonized foam can be produced without compromising pressure loss. Moreover, the time required for drying can be shortened, and the effect of reducing the manufacturing cost can also be expected.
[Brief description of the drawings]
FIG. 1 is an internal structural view showing a carbonized foam according to a preferred embodiment of the present invention.
FIG. 2 is a flowchart showing a process for producing a carbonized foam according to an embodiment.
FIG. 3 is a schematic cross-sectional view showing an internal color state (thickness of a phenolic resin applied to a base material) by cutting a coated foam obtained from an experimental example according to an experiment and a comparative example.
4 is a scanning electron micrograph showing the skeleton and the structure of the carbonized foam obtained from an experimental example related to the experiment and Comparative Example 1. FIG.
FIG. 5 shows that after application of the resin on the base material, uneven heating is performed, the temperature difference due to the heating is large, and the portion A where the coating layer is dried by sandwiching the heating boundary and drying is completed. It is the schematic which shows the motion of this resin when the site | part B where resin exists without coexisting.
[Explanation of symbols]
12 Substrate 14 Covering layer 16 Covered foam

Claims (6)

A coated foam comprising a base material (12) made of a melamine resin foam, and a required resin coating layer (14) which is applied to the inner and outer surfaces of the base material (12) and dried. 16) a carbonized foam obtained by heating and carbonizing in an oxygen-free atmosphere,
The covering layer (14) includes an external heating by hot air Drying the desired resin, is carried out inside the heating and at the same time by microwave heating or radio frequency heating, the whole is dried uniformly, and becomes homogeneous Carbonized foam characterized by The carbonized foam according to claim 1 , wherein the required resin is a thermosetting resin.   The carbonized foam according to claim 1 or 2, wherein a difference between a temperature at a site where the external heating is performed and a temperature at a site where the internal heating is performed is set within 10 ° C. Prepare a base material (12) in which the foam of melamine resin is molded into the required shape,
By applying the required resin to the inner and outer surfaces of the base material (12) as a whole and drying, a coated foam (16) having a coating layer (14) formed on the entire inner and outer surfaces,
A method for producing a carbonized foam in which the coated foam (16) is carbonized by heating in an oxygen-free atmosphere,
And external heating by Neppuinui 燥, drying the desired resin by simultaneously implementing the internal heating by microwave heating or radio frequency heating, thereby a uniform drying and homogeneity of the coating layer (14) A method for producing a carbonized foam, characterized in that it is secured. The method for producing a carbonized foam according to claim 4 , wherein a thermosetting resin is used as the required resin.   The method for producing a carbonized foam according to claim 4 or 5, wherein the temperature difference between the portion where the external heating is performed and the portion where the internal heating is performed is controlled to be within 10 ° C.

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