JP2009161677A - Method for producing dehydrated fluororubber particles - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing dehydrated fluororubber particles with high efficiency without aggregating the highly adhesive hydrous fluororubber particles. <P>SOLUTION: In the method for producing the dehydrated fluororubber particle, the dehydrated fluororubber is produced by vibrating a screen so as to transport the hydrous fluororubber on the screen 1 while jumping up and down to dehydrate the hydrous fluororubber. Concretely, the vibration is applied on the screen along a direction Di intersecting the screen surface Ps. The vibration is preferably applied to the hydrous fluororubber from the transporting direction upstream side Su to the downstream side Sd. The wedge wire screen is obliquely mounted so that the screen surface makes an angle of 70-85° to the vertical direction Dg and the hydrous fluororubber particles are preferably supplied from the high position side Sh onto the wedge wire screen. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for producing dehydrated fluororubber particles.

  In the past, “a method of separating a solid and a liquid using a wedge wire screen installed at an inclination” has been proposed (see, for example, Patent Documents 1, 2, and 3).

In addition, in the past, by putting the fluororesin-containing water-containing agglomerated particles into the filtration cylinder having a wire screen disposed in the circumferential direction, the filtration cylinder is rotated to roll the fluororesin-containing water-containing agglomerated particles. A “dehydration method” has been proposed (see, for example, Patent Document 4).
JP 59-52505 A Japanese Unexamined Patent Publication No. 60-5207 JP 2006-341227 A JP 2003-82111 A

  By the way, a method for efficiently dehydrating water-containing fluororubber particles having high tack has been sought. Therefore, the present inventors tried to apply the above-mentioned dehydration method to the hydrofluoric rubber particles, but in the former method, the hydrofluorinated rubber particles adhere to the wedge wire screen due to the high adhesiveness of the hydrous fluororubber particles. There was a problem that the fluororubber particles aggregated. On the other hand, the latter method has a problem that the hydrofluoric rubber particles are aggregated during the operation of putting the resin into a deposited state or scooping out the resin.

  An object of the present invention is to provide a method for obtaining dehydrated fluororubber particles by dewatering with high efficiency without agglomerating highly hydrous fluororubber particles.

  In the method for producing dehydrated fluororubber particles according to the first invention, the hydrofluorinated rubber particles are dehydrated by applying vibration to the screen so that the hydrofluorinated rubber particles are transported in the transport direction while jumping on the screen. Rubber particles are produced. Specifically, vibration is applied to the screen along a direction intersecting the screen surface. In addition, as a screen (sieving), a wedge wire screen, a punching metal plate, etc. can be used. Further, when the screen is installed so that the screen surface is orthogonal to the vertical direction, that is, when the screen is not inclined and installed, if vibration is applied only in the direction orthogonal to the screen surface, the hydrofluorinated rubber particles are moved in the transport direction. Not transported. Therefore, in such a case, the vibration is applied along a direction that intersects the screen surface and is not perpendicular to the screen surface. Moreover, it is preferable that the vibration is applied from the upstream side to the downstream side in the conveyance direction of the hydrofluoric rubber particles. In addition, when the screen is inclined and a vertical vibration is applied to the screen, the arrangement of the vibration source is not particularly limited. This is because the hydrofluorinated rubber particles spontaneously roll on the screen in the conveying direction due to gravity.

  In this method for producing dehydrated fluororubber particles, the hydrofluorinated rubber particles are dehydrated by applying vibration to the screen so that the hydrofluorinated rubber particles jump on the screen and are conveyed in the conveying direction. Is done. Therefore, if this method for producing dehydrated fluororubber particles is used, the contact time of the fluororubber particles with the screen can be shortened by vibration, and aggregation of the fluororubber particles due to contact between the fluororubber particles can be suppressed. . Therefore, if this method for producing dehydrated fluororubber particles is used, the adhesion of fluororubber particles to the screen can be suppressed, and the hydrous fluororubber particles can be transported quantitatively while dehydrating. Therefore, if this method for producing dehydrated fluororubber particles is used, the production efficiency of dehydrated fluororubber particles can be improved.

  The method for producing dehydrated fluororubber particles according to the second invention is the method for producing dehydrated fluororubber particles according to the first invention, wherein the screen is vibrated along a direction intersecting the screen surface.

  The method for producing dehydrated fluororubber particles according to the third invention is the method for producing dehydrated fluororubber particles according to the first invention or the second invention, wherein the vibration is applied from the upstream side to the downstream side in the transport direction.

  For this reason, when the screen is not inclined, the hydrofluoric rubber particles can be transported in the transport direction. On the other hand, when the screen is inclined, the conveyance speed of the hydrofluoric rubber particles can be improved.

  The method for producing dehydrated fluororubber particles according to the fourth invention is the method for producing dehydrated fluororubber particles according to any one of the first to third inventions, wherein the screen has an angle formed by the screen surface and the vertical direction of 70. It is installed at an angle so that the angle is between 85 ° and 85 °. The hydrofluoric rubber particles are supplied onto the screen from the high position side of the screen.

  As a result of intensive studies by the inventors of the present application, it is possible to effectively prevent the aggregation of the hydrofluoric rubber particles when the screen is inclined and installed such that the angle between the screen surface and the vertical direction is 70 ° to 85 °. It was also found that the water-containing fluororubber particles can be properly maintained in the dryness and the conveying speed. For this reason, if this method for producing dehydrated fluororubber particles is used, aggregation of the hydrofluorinated rubber particles can be effectively prevented, and the dryness and transport speed of the hydrous fluororubber particles can be appropriately maintained.

  A method for producing dehydrated fluororubber particles according to a fifth invention is a method for producing dehydrated fluororubber particles according to any one of the first to third inventions, wherein the screen has a screen surface orthogonal to the vertical direction. Installed. In addition, vibration is applied to the screen along a direction that intersects the screen surface and is not perpendicular to the screen surface.

  Therefore, if this method for producing dehydrated fluororubber particles is used, the conveyance speed can be determined only by parameters such as the vibration direction and vibration frequency. In particular, when there is a situation where it is desired to reduce the transport speed, this method for producing dehydrated fluororubber particles is suitable.

  The method for producing dehydrated fluororubber particles according to the sixth invention is the method for producing dehydrated fluororubber particles according to any one of the first to fifth inventions, wherein the screen is a wedge wire screen.

  Wedge wire screens are widely known for their efficiency of dewatering compared to other screens. For this reason, if this manufacturing method of dehydrated fluoro rubber particles is used, dehydrated fluoro rubber particles can be efficiently obtained.

  The method for producing dehydrated fluororubber particles according to the seventh invention is the method for producing dehydrated fluororubber particles according to the sixth invention, wherein the wedge wire screen is installed so that the slit line is orthogonal to the transport direction.

  When the inventors of the present application have made extensive studies, it is possible to improve the dewatering efficiency by arranging the wedge wire screen so that the slit line is orthogonal to the conveying direction rather than arranging the wedge line so that the slit line is parallel to the conveying direction. It became clear. For this reason, if this manufacturing method of dehydrated fluoro rubber particles is used, dehydrated fluoro rubber particles can be more efficiently manufactured.

  In the method for producing dehydrated fluororubber particles according to the first invention, the hydrofluorinated rubber particles are dehydrated by applying vibration to the screen so that the hydrofluorinated rubber particles are transported in the transport direction while jumping on the screen. Rubber particles are produced. Therefore, if this method for producing dehydrated fluororubber particles is used, the contact time of the fluororubber particles with the screen can be shortened by vibration, and aggregation of the fluororubber particles due to contact between the fluororubber particles can be suppressed. . Therefore, if this method for producing dehydrated fluororubber particles is used, the adhesion of fluororubber particles to the screen can be suppressed and the hydrofluorinated rubber particles can be transported quantitatively while dehydrating. Therefore, if this method for producing dehydrated fluororubber particles is used, the production efficiency of dehydrated fluororubber particles can be improved.

  When the method for producing dehydrated fluororubber particles according to the third invention is used, when the screen is not tilted, the hydrous fluororubber particles can be transported in the transport direction, and the screen is tilted. In addition, the conveyance speed of the hydrofluoric rubber particles can be improved.

  If the method for producing dehydrated fluororubber particles according to the fourth invention is used, aggregation of the hydrofluorinated rubber particles can be effectively prevented, and the dryness and transport speed of the hydrofluorinated rubber particles can be appropriately maintained.

  If the method for producing dehydrated fluororubber particles according to the fifth aspect of the invention is used, the conveying speed can be determined only by parameters such as the vibration direction and vibration frequency. In particular, when there is a situation where it is desired to reduce the transport speed, this method for producing dehydrated fluororubber particles is suitable.

  If the method for producing dehydrated fluororubber particles according to the sixth invention is utilized, dehydrated fluororubber particles can be produced efficiently.

  If the method for producing dehydrated fluororubber particles according to the seventh invention is utilized, dehydrated fluororubber particles can be produced more efficiently.

  Hereinafter, a method for producing dehydrated fluororubber particles according to an embodiment of the present invention will be described.

<Hydrofluorinated rubber particles>
Here, first, the water-containing fluororubber particles to be used in the method for producing dehydrated fluororubber particles according to the present invention will be described in detail below.

  The hydrofluoric rubber particles may be dispersed in a dispersion containing fluororubber obtained by emulsion polymerization, or may be obtained by coagulating a dispersion containing fluororubber. It may also be obtained by filtering the coagulated dispersion. The hydrofluorinated rubber particles may be a raw powder before drying obtained by suspension polymerization, or may be in a state containing moisture in the step of granulating the raw powder.

  The particle diameter of the hydrofluoric rubber particles is not particularly limited, but is preferably 100 μm or more, more preferably 150 μm or more in terms of being larger than the opening of the wedge wire screen and improving dewatering efficiency. preferable. Further, the upper limit is preferably 15 mm, and more preferably 7 mm.

  In addition, as the fluoro rubber in the hydrous fluoro rubber particles, vinylidene fluoride type fluoro rubber, propylene / tetrafluoroethylene type fluoro rubber, tetrafluoroethylene / perfluoroalkyl vinyl ether type fluoro rubber, thermoplastic fluoro rubber, fluoro silicone rubber, Examples thereof include fluorophosphanzene rubber, nitroso rubber, and fluorine-containing triazine elastomer. Among these fluororubbers, those that can be suitably used for the production method of the dehydrated fluororubber particles are vinylidene fluoride fluororubber, propylene / tetrafluoroethylene fluororubber, tetrafluoroethylene / perfluoroalkyl. Vinyl ether type fluororubber.

<Wedge wire screen>
Next, the wedge wire screen, which is an essential component for realizing the method for producing dehydrated fluororubber particles according to the present invention, will be described in detail below. In the present invention, other screens such as punch metal may be used instead of the wedge wire screen.

  The wedge wire screen is preferably configured by arranging linear members (wedge wires) having a wedge-shaped cross section in parallel so that the mesh opening is in the range of 0.02 to 2.0 mm. The opening is more preferably 0.05 to 1 mm.

  The area of the wedge wire screen, the length in the conveying direction, and the like are not particularly limited, and are appropriately selected depending on the moisture content of the hydrofluorinated rubber particles and the type of fluororubber.

  In addition, the wedge wire screen may be installed so that the screen surface is along the horizontal direction, but the screen is inclined so that the angle between the screen surface and the vertical direction (hereinafter referred to as “inclination angle”) is 70 ° to 85 °. It is preferable to install the projector so that the inclination angle is 75 to 83 °. If the installation angle of the wedge wire screen is too small, the fluororubber particles may aggregate, and if the installation angle of the wedge wire screen is too large, dehydration may be insufficient. In the present embodiment, the wedge wire screen is preferably disposed so that the slit line is orthogonal to the transport direction, but may be disposed so that the slit line is parallel to the transport direction.

<Means for vibrating the wedge wire screen>
Subsequently, means for vibrating the wedge wire screen will be described in detail below.

  The means for vibrating the wedge wire screen is not particularly limited, and examples include means for directly or indirectly connecting the vibration motor M to the wedge wire screen.

  Moreover, it is preferable to vibrate the wedge wire screen so that the amplitude of the hydrofluoric rubber particles in the conveying direction is 1 to 10 mm and the frequency in the conveying direction is 500 to 2000 cycles / min. This is because if the vibration is too small, the dehydration of the hydrofluorinated rubber particles tends to be insufficient, or the hydrous fluororubber particles tend to aggregate.

  When the wedge wire screen is vibrated in this manner, dehydrated fluororubber particles having a moisture content of 200% DB (dry base, that is, “dry standard”) or less are obtained from a mixture of 1500% or more of water and hydrous fluororubber particles. Obtainable. In the present specification, the moisture content is a value obtained by dividing the mass of moisture contained in the hydrous fluororubber particles by the mass of the dry fluororubber particles. The dry fluororubber mass means the mass of fluororubber particles after drying at 150 ° C. for 8 hours.

<Dehydration of hydrofluoric rubber particles with a vibrating wedge wire screen>
When the hydrous fluororubber particles are supplied onto the wedge wire screen, the hydrous fluororubber particles are dehydrated while being transported in the transport direction, and dehydrated fluororubber particles can be obtained. The water separated from the water-containing fluororubber particles passes through the wedge wire screen, is collected at the liquid receiver, and then drained.

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples.

  As shown in FIG. 1, the dehydrated fluororubber particle manufacturing apparatus 10 according to the present embodiment mainly includes a trough 2, a vibrator 3, and a wedge wire screen 1. As shown in FIG. 1, the trough 2 is a funnel-shaped member, and mainly includes a main body portion 2 a having a substantially inverted conical cylindrical shape and a foot portion 2 b extending from the lower end of the main body portion 2 a. . The vibrator 3 is attached to the foot 2b side of the main body 2a of the trough 2, and is attached to the supply pipe 6 side of the hydrofluoric rubber particles WP, that is, the upstream side Su in the transport direction Dc of the hydrofluoric rubber particles WP. Yes. The wedge wire screen 1 has a width of 300 mm, a length of 900 mm, and a clearance of 0.5 mm. And this wedge wire screen 1 is installed so that the large diameter opening of the main-body part 2a of the trough 2 may be covered, as FIG. 1 shows. At this time, the wedge wire screen 1 is installed such that the screen surface Ps is orthogonal to the vertical direction Dg, as shown in FIG. Moreover, this wedge wire screen 1 is arrange | positioned so that a slit line may be orthogonal to the conveyance direction Dc.

  Then, the amplitude of the vibrator 3 is set to 6 mm, and the vibrator 3 is set so that the vibration direction Di forms an angle of about 30 ° with respect to the screen surface Ps of the wedge wire screen 1. While applying vibration, the hydrofluorinated rubber particles WP and water after coagulation were supplied from the supply pipe 6 at a ratio of 15:85, respectively. Then, the hydrofluoric rubber particles WP are transported toward the transport direction Dc while bouncing and rolling on the wedge wire screen 1 by vibration, and finally roll off from the end of the wedge wire screen 1 on the downstream side Sd in the transport direction Dc. went. On the other hand, the water WT that passed through the wedge wire screen 1 was discharged from the foot 2 b of the trough 2. At this time, the supply amount of the hydrofluoric rubber particles WP and water was 57 kg / min in total. That is, the supply amount of the hydrofluoric rubber particles is 8.5 kg / minDB. Moreover, the particle size of the hydrofluoric rubber particles WP was 3 to 5 mm.

  And finally, when the wedge wire screen 1 was observed, the hydrous fluoro rubber particle WP hardly adhered to the wedge wire screen 1. The water content of the fluororubber particles DP after dehydration was 80% DB. Further, when the hydrofluorinated rubber particles WP were conveyed while being dehydrated on the wedge wire screen 1, some aggregation of the particles was observed due to the contact between the hydrofluorinated rubber particles WP.

  It should be noted that the main feature points in this embodiment are summarized in Table 1 and should be referred to.

  As shown in FIG. 2, the wedge wire screen 1 in the dehydrated fluororubber particle production apparatus 10 shown in Example 1 is inclined so as to have a downward gradient of 10 degrees from the upstream side Su to the downstream side Sd. Except for the above, dehydrated fluororubber particles WP were produced under the same conditions as in Example 1. In the dehydrated fluororubber particle manufacturing apparatus 10A shown in this embodiment, the supply pipe 6 is disposed on the high position side Sh of the wedge wire screen 1 as shown in FIG. As a result, the hydrofluorinated rubber particles WP could be transported on the wedge wire screen 1 more efficiently than in Example 1, and the hydrous fluororubber particles WP could be prevented from aggregating with each other. Further, the moisture content of the fluororubber particles DP after dehydration is 80% DB, and the dehydrated fluororubber particle production apparatus 10A shown in Example 2 is equivalent to the dehydrated fluororubber particle production apparatus 10 shown in Example 1. It was confirmed to have a dehydrating ability. Finally, when the wedge wire screen 1 was observed, the adhesion of the hydrofluoric rubber particles WP to the wedge wire screen 1 was further reduced as compared with Example 1.

  It should be noted that the main feature points in this embodiment are summarized in Table 1 and should be referred to.

(Comparative Example 1)
As shown in FIG. 3, the wedge wire screen 1 similar to that of the first embodiment is tilted so as to have a downward slope of 70 degrees from the upstream side Su to the downstream side Sd in the transport direction, and no vibration is given. Except for the above, dehydrated fluororubber particles WP were produced under the same conditions as in Example 1 (see FIG. 3). In the dehydrated fluororubber particle production apparatus 10B shown in the present embodiment, the supply pipe 6 is disposed on the high position side Sh of the wedge wire screen 1 as shown in FIG. As a result, the transport state of the hydrofluorinated rubber particles WP on the wedge wire screen 1 was not uniform, and a large amount of aggregation of the hydrofluorinated rubber particles WP occurred. Finally, when the wedge wire screen 1 was observed, the wet fluorine rubber particles WP were often attached to the wedge wire screen 1. The moisture content of the fluororubber particles DP after dehydration was 140% DB, and a sufficient dehydration effect was not obtained as compared with Example 1 and Example 2.

  It should be noted that the main feature points in this embodiment are summarized in Table 1 and should be referred to.

  The method for producing dehydrated fluororubber particles according to the present invention is characterized in that the adhesion of the hydrofluorinated rubber particles to the wedge wire screen can be suppressed and the hydrous fluororubber particles can be transported quantitatively while dehydrating. And is very effective in the production of dehydrated fluororubber particles.

1 is a simplified configuration diagram of a dehydrated fluororubber particle production apparatus according to Example 1. FIG. It is a simple block diagram of the dehydration fluoro rubber particle manufacturing apparatus which concerns on Example 2. FIG. It is a simple block diagram of the dehydration fluororubber particle manufacturing apparatus which concerns on the comparative example 1.

Explanation of symbols

1 Wedge wire screen Dc Transport direction (specific direction)
Dg Vertical direction Di Direction intersecting with screen surface Ps Screen surface Sh High position side of wedge wire screen Su Conveyance direction of hydrous fluororubber particles Sd Conveyance direction of hydrous fluororubber particles Downstream side WP Hydrous fluororubber particles

Claims (7)

A vibration is applied to the screen so that the water-containing fluororubber particles (WP) jump on the screen (1) and is transported in the transport direction (Dc) to dehydrate the water-containing fluororubber particles to produce dehydrated fluororubber particles. A method for producing dehydrated fluororubber particles. The method for producing dehydrated fluororubber particles according to claim 1, wherein vibration is applied to the screen along a direction (Di) intersecting the screen surface (Ps). The vibration is applied from the upstream side (Su) to the downstream side (Sd) in the transport direction.
A method for producing dehydrated fluororubber particles according to claim 1 or 2. The screen is installed so as to be inclined so that an angle between the screen surface and the vertical direction (Dg) is 70 ° to 85 °,
The hydrofluoric rubber particles are supplied onto the screen from the high position side (Sh) of the screen.
The method for producing dehydrated fluororubber particles according to any one of claims 1 to 3. The screen is installed such that the screen surface is orthogonal to the vertical direction,
The method for producing dehydrated fluororubber particles according to any one of claims 1 to 3, wherein the screen is vibrated along a direction that intersects the screen surface and is not perpendicular to the screen surface. The method for producing dehydrated fluororubber particles according to claim 1, wherein the screen is a wedge wire screen. The said wedge wire screen is a manufacturing method of the dehydrated fluororubber particle of Claim 6 installed so that a slit line may orthogonally cross the said conveyance direction.

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