JPS61110510A - Crushing method of water-soluble polymer gel - Google Patents

Abstract

PURPOSE:To contrive an improvement in water-solubility, by cutting off a vinyl series monomer gel in a state of a narrow paper tablet and then in a state of a splinter. CONSTITUTION:A polymer gel obtained by polymerizing a water solution of a water-soluble vinyl series monomer is supplied to a roller type cutters 3, 4. As for the supply, it is desirable to perform the same continuously by a method wherein a polymer gel is unloaded continuously from the other end of an endless belt, which is made to intrude upon a roller type cutter. A strand of an article made into a state of a narrow paper tablet, for example, a strand of a polymer gel cut off in the state of the narrow paper tablet by the roller type cutters 3, 4 rotating in the direction wherein they are meshing with each other is peeled off from the external circumferential part of an inner blade A of a roller type cutter by edges at the top of combs 5, 6, descended between the combs 5, 6 and made into a state of a splinter with a stationary blade 2 and a rotating blade 1 of a rotor 10.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for crushing water-soluble polymer gel. More specifically, the water-soluble polymer gel is crushed by cutting the polymer gel obtained by polymerizing an aqueous solution of a water-soluble vinyl monomer into short pieces and cutting the rough pieces into small pieces. Regarding the method.

[Prior Art] Conventionally, acrylamide homopolymers, copolymers mainly composed of acrylamide with other polymerizable monomers, or alkaline hydrolysates thereof have been used as paper strength agents and thickeners. It is widely used as a soil conditioner, crude oil recovery agent, wastewater treatment agent, etc.

Methods for producing these water-soluble acrylamide polymers include bulk polymerization, suspension polymerization, emulsion polymerization, and solution polymerization, but since polymers with essentially high molecular weight are used, aqueous solution polymerization is usually used. is often adopted.

In order to obtain a polymer having a very high molecular weight and good water solubility by an aqueous solution polymerization method, it is necessary to conduct the polymerization at a relatively low concentration, also in the sense of preventing crosslinking in the polymerization reaction stage.

However, in recent years, as emphasis has been placed on economic efficiency such as transportation costs and storage costs, powder products have become the mainstream of production rather than liquid products, and when water-soluble polymerization is carried out at low concentrations, When powdering a polymer, a large amount of water must be volatilized and drying must be carried out, which has the drawback of increasing utility costs for powdering.

In order to eliminate such drawbacks, research has been conducted to carry out polymerization at the highest possible monomer concentration to reduce utility costs in the powdering step, and numerous patent applications have been filed.

However, vinyl-based compounds such as acrylamide and acrylic acid inherently have a very strong tendency to crosslink and become three-dimensional, and therefore, it is necessary to have relaxed conditions for preventing crosslinking, especially regarding monomer concentration, e.g. In the case of anionic or nonionic, at most 20 to 30
The polymerization must be carried out while maintaining the concentration at a relatively low concentration of % (weight %, same hereinafter).

When acrylamide or a monomer solution mainly consisting of acrylamide at the above concentration is polymerized, a hard or highly elastic gel-like material having no fluidity is obtained. Therefore, for example, if you try to volatilize the water contained in the gel polymer lump or sheet without mechanically crushing it, it will take a very long time.
It is necessary to leave the product under high temperature, and as a result, the molecular weight of the high molecular weight polymer that has been carefully prepared decreases, and crosslinking of the polymer due to thermal changes is promoted, resulting in a significant decrease in commercial value.

Therefore, generally, a method is adopted in which the obtained polymer gel lump or sheet-like material is crushed into small particles by some mechanical means, and then dried by heating to remove water. There is.

Generally, a method is widely adopted in which a polymer gel obtained by polymerization is crushed into strands by forming it into a strand using an extruder such as a meat grinder. However, when using an extrusion molding machine such as a meat grinder, if the polymer gel is extremely hard, there will be large friction with the machine wall, which will not only cause a loss of machine efficiency, but also cause the polymer gel itself to As a result of deterioration due to frictional heat and physical forces, the molecules that have been made to have a high molecular weight during the polymerization stage are severed, and as a result, the high molecular weight substance cannot be converted.

As an improvement method, a method has been proposed in which the frictional resistance of the machine is reduced by using a lubricant such as polyethylene glycol or nonionic surfactant during extrusion molding, but in order to obtain the desired effect, This requires the use of a large number of chemicals, which leads to unfavorable results such as a decrease in purity, an increase in sliminess when powdered, and a decrease in free-flowing properties of the powder.

For these reasons, there is a desire for a method of crushing the polymer gel obtained by polymerization into fine particles without deterioration due to frictional heat, physical forces, etc., and without causing a decrease in molecular weight.

[Problems to be Solved by the Invention] The present invention solves the problem of deterioration of the polymer due to frictional heat and physical force that occur when crushing the polymer gel as described above, and the deterioration of the polymer gel that occurs when crushing using a lubricant. This aims to solve problems such as a decrease in the content of the powder, an increase in sliminess when powdered, and a decrease in the free-flowing properties of the powder.

Means for Solving Problem E] The present invention provides a method of crushing a polymer gel obtained by polymerizing a water-soluble vinyl polymer as a first-stage crushing method using rotation in mutually interlocking directions. The polymer gel is inserted into a pair of roller-type cutters and cut into short pieces, and the resulting short pieces of polymer gel are then cut into strips using a rotating blade and a fixed blade. The present invention relates to a method for crushing a water-soluble polymer gel.

[Example] Examples of water-soluble vinyl monomers used in the present invention include water-soluble vinyl monomers such as acrylamide, methacrylamide, acrylic acid, methacrylic acid, vinylsulfonic acid, acrylamide-methylpropanesulfonic acid, and itaconic acid. (meth)acrylic acid dialkylaminoalkyl esters, salts or acidic salts thereof, or quaternized products thereof, dialkylaminoalkylacrylamides, salts or acidic salts thereof, or quaternary products thereof;
Examples include, but are not limited to, diallylamines such as graded compounds, diallylamine acid salts, and diallyldialkylammonium salts. These may be used alone or in combination of two or more.

The water-soluble vinyl monomers include monomers that are essentially insoluble in water to the extent that the resulting polymer is water-soluble, such as acrylonitrile, (meth)acrylates, vinyl acetate, and styrene. Hydrophobic monomers such as these may also be blended.

There are no particular limitations on the method of polymerizing the water-soluble vinyl monomer, such as thermal polymerization using a radical polymerization initiator such as a known persulfate or an azo initiator, a method using known persulfates/amines, or Common methods include a redox polymerization method using a redox polymerization initiator such as persulfate/sulfite, a photopolymerization method using a photopolymerization initiator such as benzoin or benzoin alkyl ether, or a radiation polymerization method. Usually, by such a method, an aqueous solution of a water-soluble vinyl monomer of a predetermined concentration is polymerized until it no longer flows freely.

When the above-described aqueous solution of a water-soluble vinyl monomer is polymerized by ultraviolet irradiation, not only does the polymerization start with almost no induction time, but the polymerization rate is significantly higher than that of other methods. The required time is short and it is efficient. This method is particularly suitable for polymerization at high concentrations, and is compact when polymerizing in a thin layer on a movable support and subsequently feeding it continuously to a crusher such as the one used in the present invention. It can be said to be a preferable polymerization method because it has the advantage of being able to be carried out with modern equipment without significantly reducing productivity.

It is preferable for the polymer gel obtained using water-soluble vinyl monomers to have as high a concentration as possible from the viewpoint of improving productivity. It is also preferable from the viewpoint of prevention. Generally, nonionic or anionic polymer gel obtained using acrylamide or acrylic acid has a content of 20 to 60%,
It is preferably 30 to 45%. On the other hand, in the case of a cationic polymer gel using dialkylaminoalkyl acrylate or its acid salt or quaternary salt, 50 to 9
0%, preferably 60-80%.

The morphology of the polymer gel is one that rotates in the interlocking direction.
In order to cut efficiently with a pair of roller-type cutters, the polymer gel must be inserted into the roller-type cutter smoothly, so the polymer gel must be cut into a thin layer with a thickness of 2 to 30 ml, preferably 5 to 15 ml. It is preferable to do so. For example, when an aqueous solution of a water-soluble vinyl monolayer is polymerized using a dish-type, flat-plate-type, or tray-type container or a movable belt, it can be formed into a thin layer.

The method of polymerizing in a thin layer on a movable belt is a preferred method because subsequent crushing is continuous.

In the present invention, the polymer gel obtained as described above is crushed using a crusher as shown in one embodiment in FIGS. 1 to 3.

The polymer gel is fed into the crusher from above the crusher as shown in FIG. The supplied polymer gel is cut into short pieces by the roller cutters (3) and (4) shown in Figure 3, which is a top view of the crusher shown in Figures 1 and 2. Be made into strands.

As shown in Figure 3, and more specifically in Figures 4 and 5, the surfaces of the roller type cutters (3) and (4) are provided with cutter blades in a concave and convex shape so that the concavities and convexities engage with each other. It is formed. The intermeshed roller-type cutters, for example, have the same dimensions and rotate at the same rotational speed in the interlocking direction. The width, depth, and height of the unevenness of the blades formed to interlock with each other may be determined depending on the desired size of the crushed polymer gel; for example, the width (X+) in FIG. 5 is 2 to 10 mm. The depth of the concave part x 4) is about 10 to 15 mm, and the height of the convex part x 5) is 1
0 to 15IllI11, and even when the concave part and the convex part are most deeply engaged, the gap ((X3) in Figure 5) necessary for the cut polymer gel to pass through is 10
It is usually formed with a gap of about 25 mm. The blades on the surfaces of the roller type cutters (3) and (4) are formed in such a shape, and the rotating shaft (8) of the roller type cutter shown in FIG.
), (9) using two roller type cutters (3),
(4) is rotated as shown in Figure 2 (A-A cross-sectional view in Figure 1), and the polymer gel supplied from above is caught and cut, and the polymer gel is supplied downward. The polymer gel can be easily cut, for example, into short pieces in the form of strands.

In order to supply the polymer gel to the roller type cutters (3) and (4), there is a method in which the polymer gel is continuously taken out from the other end of a movable support, such as an endless belt, and then inserted into the roller type cutter. If the process is carried out continuously, the entire process can be made continuous, and production efficiency can be improved.

Next, a method of cutting the short strand into strips will be explained.

Roller-type cutters (3) that rotate in the direction of mutual engagement
), (4), for example, the polymer gel strands cut into short pieces are shown in FIG. 2 (5), (6).
) is separated from the outer periphery of the inner blade (A>) of the roller type cutter, descends between the comb (5) and <Li2), and is separated from the fixed blade (<L, +61) provided at the lower end. The strand of polymer gel normally does not get caught in the outer blade (8) of the roller type cutter.The strand of polymer gel reaches the position of the fixed blade (2) The strand-shaped strands are shown in Figures 1 and 2 ('7
The blade is cut by a cutting force acting between a rotary blade (1) and a fixed blade (2) provided on the outer periphery of a rotating body (10) with rotation axis 1, and is cut into strips, preferably about 3~ 20! lll1
It is made into a square shape.

The cross-sectional shape of the short piece in the horizontal direction is determined by the machine dimensions of the roller cutters [3) and [4] after assembly, that is, the width of the unevenness of the blade (X+), the height x 4), and (Xs).
, the depth of engagement x 2) and the rotational speed of the roller type cutters (3) and (4).

The rotational speed of the roller type cutters (3) and (4), the rotational speed of the rotating body (10) that rotates at a speed synchronized therewith, and the rotating blade (1) provided on the rotating body (10).
By adjusting the number of strips (six in FIG. 2), the length to be cut into strips can be determined.

When cutting polymer gel with a crusher, the temperature of the polymer gel at the time of cutting should be kept as low as possible in order to increase cutting efficiency and prevent redeposition of the resulting pieces of polymer gel. It is preferable to prevent the temperature of the polymer gel from increasing due to heat generated during cutting.

Methods for lowering the humidity of the polymer gel include a method of sufficiently cooling it during the polymerization stage, a method of forcibly cooling the polymer gel obtained by polymerization with cold air, etc. before crushing it with a crusher, etc. , but usually 1
It is preferable to adjust the temperature to 0 to 30°C, preferably 20°C or less.

Furthermore, if the crushing process is cooled by blowing cold air, preferably cold air at a temperature of 25°C or lower, to produce short strands, and then the strands are further cut into strips, the friction at the time of cutting is It is possible to reduce the possibility that the polymer gel becomes sticky due to heat or the driving heat of a roller type cutter, or that the cut pieces of the polymer gel adhere to each other and form blocks.

Adopting such a method is effective because it increases crushing efficiency.

If necessary, polyethylene glycol, nonionic surfactants, anionic surfactants, etc. may be added to the crusher or applied to the surface of the polymer gel to prevent the pieces of polymer gel from re-adhering. You can also

Next, the method of the present invention will be explained based on examples.

Example 1 A polymerization apparatus with a jacket (length: 200 ml, width: 300 mm, height: 5
A 0 ml 1 liter square container (without top lid) was installed.

150 g of acrylamide, 38 g of acrylic acid, and 20 g of caustic soda, from which dissolved oxygen was sufficiently removed using nitrogen gas in a deoxidizing tank (cylindrical type with a capacity of 116 mm), were mixed with 275 g of deionized water.
Add 5% potassium persulfate aqueous solution 5Id and 5% sodium sulfite aqueous solution 5d to the monomer aqueous solution dissolved in g,
After continuing to deoxidize with nitrogen gas for several minutes, the mixture was introduced into the polymerization apparatus installed in a room sealed with nitrogen gas, and polymerization was started. Water at 25°C was passed through the jacket. Polymerization started after about 10 minutes, and the aqueous monomer solution gradually thickened. When 15 minutes had passed after the start of polymerization, the monomer aqueous solution was in a state of gently flowing.

Approximately 2 hours after the start of polymerization, the polymer became a hard gel. The polymer gel was approximately 8 mlg thick.

The resulting polymer gel was crushed using a crusher as shown in Figures 1 to 3, with a roller-type cutter having 5 mm in the unevenness, 15 mm in the depth of the concave, 14 m +++ in the height of the convex, and 7 mm in the depth of engagement. The slit between the blade and the rotating outer diameter of the rotary blade is 0.
A crusher with a diameter of 3 mm and a rotation speed of a rotary blade of 20 to 100 r/min was used to crush the material at 20°C by adjusting the rotation speed of the rotary blade using a roller type cutter with a surface speed of 30 cm/min. A strip-shaped gel of mm square was obtained.

The obtained strip-like gel had almost no adhesion between the polymer gels and was in a loose state.

Comparative Example 1 An attempt was made to extrude the polymer gel obtained in Example 1 using a small meat grinder, but the polymer gel was so hard that it was impossible to move the small meat grinder.

Approximately 1% polyethylene glycol (MW 600) was applied to the surface of the polymer gel, and when it was extruded using a small meat grinder, it was barely broken into pieces and dangling, but the resulting polymer gel was compatible with each other. It was found that the particles were tied together like a string, and the particles were kneaded together, and mechanical deterioration was clearly caused by frictional heat and physical force.

Example 2 500 g of an 80% aqueous solution of N, N, N-trimethylaminoethyl methacrylate chloride was collected, and after adjusting the pH to 4 using a 10% aqueous hydrogen chloride solution, the total amount was made up to 565 g with distilled water. Thereafter, it was charged into the polymerization container used in Example 1, and polymerized in the same manner as in Example 1.

The resulting polymer gel was a hard polymer gel with a thickness of 9.4n+m.

When the polymer gel was crushed in the same manner as in Example 1 using the crusher of Example 1 with the width of the slit of the fixed blade/rotary blade being 0.5 mu+, the gel was easily transformed into fine granular gel of 3×8×5IIllIl square. Ta.

Comparative Example 2 When an attempt was made to crush the polymer gel obtained in Example 2 using a small meat grinder, the polymer gel was too hard and could not be crushed due to poor penetration.

Example 3 Tetrafluoroethylene-ethylene copolymer film (
Medium 450mm with a thickness of 50μm), effective length 3.0
An endless belt made of 00mn+ stainless steel uA with a structure capable of spraying hot to cold water on the back side was installed as a movable support for polymerization in a chamber completely filled with nitrogen gas, and the belt was heated at 30l1lIIl/min. The belt was moved at a constant speed of 25° C. and water at 25° C. was sprayed onto the back surface of the belt.

N with a concentration of 75% adjusted to pH 4 with a 10% aqueous hydrochloric acid solution,
The N,N-trimethylaminoethyl methacrylate chloride monomer aqueous solution layer 3012 is sufficiently degassed with nitrogen gas, and the layer 101/
The feed was directed from one end of the belt at a rate of 1 hour.

To mix the polymerization initiator and monomer aqueous solution, separately put a 5% potassium persulfate solution and a sodium sulfite solution as polymerization initiators into two temporary storage tanks (5ff capacity) equipped with a stirrer installed above the belt, and add 70ml each. ! /
Polymerization started in 20 minutes after the monomer aqueous solution was supplied onto the belt while being uniformly mixed with the monomer aqueous solution at a constant speed. It continued to be supplied continuously.

The time that the monomer aqueous solution is subjected to polymerization on the belt is 10
0 minutes, the monomer aqueous solution layer during polymerization is approximately 12 mm.
And the total polymerization time was 2 hours.

After 12,020 minutes from the start of supply of the seven-mer aqueous solution, a sheet-like polymer having a thickness of about 12 IllIll was transferred from the other end of the belt. The obtained polymer could be easily peeled off from the belt surface by hand, and continuous polymerization for about 3 hours was possible.

The temperature of the resulting polymer gel was about 28°C.

The polymer gel sheet continuously obtained from the other end of the endless belt is crushed into pieces with a width of 5 mm using a crusher as shown in Figs.
n+m, depth of recess 15RIIl, height of protrusion 14m1
, the slit width between the fixed blade and the rotating outer diameter of the rotary blade is 0.5 mm.
, using a crusher with a rotation speed of the rotary blade of 20 to 100 r/min, the surface speed of the roller cutter is 30 c.
The mixture was continuously fed to a crusher with a rotating blade whose rotational speed was adjusted at 11/min, and the mixture was shredded into small pieces. Approximately 5X12X from the crusher outlet
A polymer gel fragmented into 511111 corners was continuously removed. There was very little adhesion between the pieces of polymer gel, and they were in a state of being separated from each other.

When continuously crushing a polymer gel sheet, blowing cold air adjusted to about 15°C into the inlet of the crusher will harden the finely divided polymer gel and reduce the frictional heat of the cutting machine. There was almost no generation, and the fragmentation efficiency was significantly improved.

Example 4 Made of stainless steel, width 450mm, effective length 3.000m
A polytetrafluoroethylene-ethylene copolymer film whose back side is vapor-deposited with aluminum is attached to an endless belt of 1.0 m, and the structure is such that hot to cold water can be sprayed onto the endless belt from below. Installed as a movable support in a room completely filled with nitrogen gas,
The belt was operated at a low speed of 0 mm for 7 minutes, and water at 15° C. was sprayed from below the belt. Furthermore, a low-pressure mercury lamp was installed as an ultraviolet irradiation source above the movable support, and the intensity of ultraviolet rays was set to 50 W/m''.

N with a concentration of 75% adjusted to pH 4 with a 10% aqueous hydrochloric acid solution,
Approximately 40 d of an aqueous solution of N,N-1-limethylaminoethyl methacrylate chloride monomer is thoroughly degassed with nitrogen gas, and is poured onto the belt in operation at a rate of 13.512/hour from one end of the belt at a constant = 20 − Quantity supplied.

In addition, there is a temporary storage tank (5I) with an agitator installed above the belt.
A 5% methanol solution of benzoin isopropyl ether as a polymerization initiator was supplied into the monomer aqueous solution at a rate of 30 d/hour from a 2-volume suspension), and the monomer aqueous solution and the polymerization initiator were uniformly mixed while being supplied onto the belt. Polymerization was carried out by ultraviolet irradiation.

Under the above conditions, the time during which the monomer aqueous solution was subjected to polymerization on the belt was 30 minutes, and the monomer aqueous solution layer during polymerization was about 5111 Ill.

Thirty minutes after the start of supply of the monomer aqueous solution, a sheet-like polymer having a thickness of 5 mm was transferred from the other end of the endless belt. The obtained polymer was in a state where it could be easily peeled off manually from the belt surface, and continuous polymerization for about 3 hours was possible.

The temperature of the obtained polymer gel was 20°C.

The polymer gel sheet obtained continuously from the other end of the endless belt is shaped into a shape with a width of 5 mm as shown in Figures 1 to 3.
n+m, depth of recess 1511J height of convexity 14mm, slit width of fixed blade and rotary blade 051, rotation speed of rotary blade 2
Using a crusher with a speed of 0 to 100 r/min, the surface speed of the roller type cutter was 10011+11/min, and the number of revolutions of the rotary blade was adjusted. Pieces of the polymer gel, each having a size of about 3×5×5 mm square and free of mutual adhesion, were continuously taken out.

[Effects of the Invention] The method of the present invention provides the following advantages: (1) Even if the polymer gel is very hard, it can be easily broken into pieces without reducing the molecular weight of the polymer by mechanical friction or physical force. (2) Since the fragmented gel does not stick to each other and is in pieces, and is finely divided, it significantly improves the drying efficiency during drying. (3) It can be a continuous process from the polymerization step to the drying step. (4) Adopting a polymerization method by irradiating ultraviolet rays is excellent in that YJn can be made more compact.

[Brief explanation of the drawing]

FIG. 1 is a front view of an embodiment of a crusher used in the present invention;
Fig. 2 is a sectional view taken along the line A-A' of the crusher shown in Fig. 1, Fig. 3 is a plan view of the crusher shown in Fig. 1, Fig. 4 is an explanatory diagram of the engaging portion of the roller cutter, and Fig. 5 is a cross-sectional view of the crusher shown in Fig. 1. The figure is an enlarged explanatory view of the engaging portion shown in FIG. 4. (Main symbols in the drawings) (1) Two-rotating blade (2): Fixed blade (3), (4): Roller type cutter = 24- First diagram 4: Roller type force. Figure 2/Yuichi Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] 1. When crushing a polymer gel obtained by polymerizing an aqueous solution of a water-soluble vinyl monomer, the polymer gel is bitten into a pair of roller-type cutters that rotate in a mutually interlocking direction. 1. A method for crushing a water-soluble polymer gel, which comprises cutting the polymer gel into short pieces using a rotary blade and a fixed blade. 2. The crushing method according to claim 1, wherein the polymer gel is continuously fed to a crusher using a movable support and is continuously cut into strips. 3. The crushing method according to claim 1 or 2, wherein the polymer gel is a polymer gel obtained by irradiating an aqueous solution of a water-soluble vinyl monomer with ultraviolet rays. 4. The crushing method according to claim 1, 2, or 3, wherein the polymer gel is cut into strips while passing cold air at 25° C. or lower.