JP2010077340A - (meth)acrylic acid-based polymer, application thereof, and method for producing (meth)acrylic acid-based polymer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a (meth)acrylic acid-based polymer that has extremely excellent dispersibility in calcium carbonate slurry and a narrow molecular weight distribution and exhibits particularly excellent performance when used for a dispersant, a detergent composition, a water treatment agent, a scale inhibitor, or the like, and a method for producing the same. <P>SOLUTION: In the (meth)acrylic acid-based polymer, the molar ratio of the amount of phosphorus atom located at the end of the main chain to the amount of phosphorus atom incorporated into the main chain is three or more, and the molecular weight distribution is 2.8 or less. The method for producing the (meth)acrylic acid-based polymer includes polymerizing a monomer component including a (meth)acrylic acid-based monomer while circulating a circulating liquid containing the monomer component through a circulating line 2 which extends from a tank 1 and circulates outside the tank and returns to the tank. The circulating line is provided with a supply inlet 11 through which a phosphorus-containing compound is supplied, at least one cooler 4, and a discharge line 3 through which a portion of the circulating liquid is discharged out of the circulating line; wherein 3 to 7 g of the phosphorus-containing compound based on 1 mole of the (meth)acrylic acid-based monomer is supplied. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a (meth) acrylic acid polymer, its use, and a method for producing a (meth) acrylic acid polymer.

  (Meth) acrylic acid polymers are known as water-soluble polymers suitable for dispersants, detergent compositions, water treatment agents, scale inhibitors, and the like.

  (Meth) acrylic acid heavy metals that can express exceptional performance when used in dispersants, detergent compositions, water treatment agents, scale inhibitors, etc., and can be manufactured with high efficiency on an industrial scale Coalescence is desired.

  As the (meth) acrylic acid polymer as described above, a (meth) acrylic acid polymer having a relatively good dispersibility of the calcium carbonate slurry is known (see Patent Document 1). The (meth) acrylic acid polymer described in Patent Document 1 is produced using phosphorous acid as a chain transfer agent. However, the (meth) acrylic acid polymer described in Patent Document 1 has not yet reached a sufficient level of dispersibility of the calcium carbonate slurry.

  On the other hand, as a method for producing a (meth) acrylic acid polymer, a method for producing a high-concentration sodium polyacrylate in batch polymerization with controlled foaming and temperature is known (see Patent Document 2). However, the production method described in Patent Document 2 uses a batch-type reactor having a cooling device, a tank reactor, and a stirring mixer, so that an excessively large device is required to ensure high productivity. Is required. Furthermore, the molecular weight distribution (Mw / Mn) of the resulting (meth) acrylic acid polymer becomes relatively large, and it is exceptional when used as a dispersant, detergent composition, water treatment agent, scale inhibitor, etc. It is difficult to develop excellent performance. The molecular weight distribution (Mw / Mn) is represented by a quotient obtained by dividing the weight average molecular weight (Mw) by the number average molecular weight (Mn).

  As a method for producing a (meth) acrylic acid polymer, there is known a continuous method for producing polyacrylic acid having a narrow molecular weight distribution using a plurality of reactors installed in series (Patent Document 3). And Patent Document 4). In the examples described in Patent Document 3 and Patent Document 4, a tank-type first to third reactor, and a series of stirred tanks having a cooling device and a stirring mixer in the second reactor as necessary. A type reactor is used. This reaction apparatus is called “continuous type”, but substantially, the stirring tank is connected in series as the first to third reactors, and the reaction liquid is sequentially supplied from the first reactor to the third reactor. It is a system which is sent and taken out from the third reactor. When such a series reactor is used, it is difficult to shorten the reaction time, it is difficult to increase productivity, and the heat removal efficiency is insufficient.

  As a method for producing a (meth) acrylic acid polymer, a continuous method for producing polyacrylic acid having a narrow molecular weight distribution using a loop-type circulation line is known (see Patent Document 5). Patent Document 5 describes a circulation type continuous reaction apparatus having a tubular reactor and a motionless mixer. However, when such a circulation type continuous reaction apparatus is used, it is difficult to shorten the reaction time, it is difficult to increase productivity, and the heat removal efficiency becomes insufficient.

  Furthermore, even if a (meth) acrylic acid polymer having desired characteristics can be obtained with high efficiency on a laboratory scale, it cannot be obtained in the same manner when manufactured on an actual production equipment scale. Can occur.

On the other hand, a continuous production method capable of producing a water-soluble polymer having a narrow molecular weight distribution with high efficiency is known (see Patent Document 6).
JP 2001-70778 A JP 2004-244617 A JP 2003-002909 A JP 2003-040912 A JP 2001-098002 A JP 2007-217654 A

  The problem of the present invention is that the dispersibility of the calcium carbonate slurry is very excellent, the molecular weight distribution is narrow, and when used as a dispersant, a detergent composition, a water treatment agent, a scale inhibitor, etc., exceptional performance can be expressed. Another object of the present invention is to provide a (meth) acrylic acid polymer that can be produced with high efficiency on an industrial scale and its use. Moreover, it is providing the manufacturing method of such a (meth) acrylic-acid type polymer.

In the (meth) acrylic acid polymer of the present invention, the ratio of the main chain internal insertion phosphorus atom weight to the main chain terminal-arranged phosphorus atom weight is 3 or more in terms of molar ratio, and the molecular weight distribution is 2.8 or less.
The (meth) acrylic acid polymer of the present invention also has
The monomer component is polymerized while circulating the circulating liquid containing the monomer component including the (meth) acrylic acid-based monomer to the circulation line that comes out of the tank, circulates outside the tank, and returns to the tank. A (meth) acrylic acid polymer obtained by the production method
The circulation line includes a supply port for supplying a phosphorus-containing compound, at least one cooler, and a discharge line for discharging a part of the circulation liquid to the outside of the circulation line;
3-7 g of the phosphorus-containing compound is supplied to 1 mol of the (meth) acrylic acid monomer.
According to another aspect of the present invention, a dispersant is provided. The dispersant of the present invention contains the (meth) acrylic acid polymer of the present invention.
According to another aspect of the invention, a detergent composition is provided. The detergent composition of the present invention contains the (meth) acrylic acid polymer of the present invention.
According to another aspect of the present invention, a water treatment agent is provided. The water treatment agent of the present invention contains the (meth) acrylic acid polymer of the present invention.
According to another aspect of the present invention, a scale inhibitor is provided. The scale inhibitor of the present invention contains the (meth) acrylic acid polymer of the present invention.
According to another aspect of the present invention, a method for producing a (meth) acrylic acid polymer is provided. The production method of the (meth) acrylic acid polymer of the present invention is as follows:
The monomer component is polymerized while circulating the circulating liquid containing the monomer component including the (meth) acrylic acid-based monomer to the circulation line that comes out of the tank, circulates outside the tank, and returns to the tank. A method for producing a (meth) acrylic acid polymer,
The circulation line includes a supply port for supplying a phosphorus-containing compound, at least one cooler, and a discharge line for discharging a part of the circulation liquid to the outside of the circulation line;
3-7 g of the phosphorus-containing compound is supplied to 1 mol of the (meth) acrylic acid monomer.

  According to the present invention, the dispersibility of the calcium carbonate slurry is very excellent, the molecular weight distribution is narrow, and when used as a dispersant, a detergent composition, a water treatment agent, a scale inhibitor, etc., it is possible to express exceptional performance. In addition, it is possible to provide a (meth) acrylic acid polymer that can be produced with high efficiency on an industrial scale and its use. Moreover, the manufacturing method of such a (meth) acrylic-acid type polymer can be provided.

  The above effect is such that the (meth) acrylic acid polymer has phosphorus atoms in the main chain terminal and the main chain of the polymer, and the ratio of the main chain internal insertion phosphorus atomic weight to the main chain terminal arranged phosphorus atomic weight. Can be expressed by setting the molar ratio to a predetermined value or more and the molecular weight distribution to a predetermined value or less.

  The above-described effect is also achieved in that a circulating liquid containing a monomer component including a (meth) acrylic acid monomer is removed from the tank as a (meth) acrylic acid polymer and circulated outside the tank. A (meth) acrylic acid polymer obtained by a production method in which the monomer component is polymerized while being circulated through a circulation line returning to the tank is adopted, and the circulation line has at least one supply port for supplying a phosphorus-containing compound. Two coolers and a discharge line for discharging a part of the circulating liquid to the outside of the circulation line, and a predetermined amount of the phosphorus-containing compound with respect to 1 mol of the (meth) acrylic monomer. By supplying within the range, it becomes possible to express.

  The above effect is also achieved as a method for producing a (meth) acrylic acid polymer by removing a circulating fluid containing a monomer component containing a (meth) acrylic acid monomer from the tank and leaving the outside of the tank. Adopting a method for producing a (meth) acrylic acid polymer that circulates and circulates the monomer component in a circulation line returning to the tank, and the circulation line supplies a phosphorus-containing compound. And at least one cooler and a discharge line for discharging a part of the circulating liquid to the outside of the circulating line, and further, the phosphorus-containing compound is added to 1 mol of the (meth) acrylic monomer. It can be expressed by supplying it within a predetermined range.

≪A. (Meth) acrylic acid polymer production equipment >>
Initially, the (meth) acrylic-acid-type polymer manufacturing apparatus used for the manufacturing method of this invention is demonstrated. FIG. 1 is a conceptual diagram illustrating a (meth) acrylic acid polymer production apparatus according to one embodiment of the present invention. FIG. 2 is a conceptual diagram illustrating a (meth) acrylic acid polymer production apparatus according to another embodiment of the present invention. The (meth) acrylic acid polymer production apparatus 100 includes a tank 1, a circulation line 2, and a discharge line 3. The tank 1 temporarily stores a circulating fluid containing a monomer component including a (meth) acrylic acid monomer. The circulation line 2 exits from the outlet a of the tank 1, circulates outside the tank 1, and returns to the return port b of the tank 1 (that is, the circulation line is a so-called loop type). The circulation line 2 is usually provided with a circulation pump 6 and a mixing device 5, and circulates the circulating liquid while mixing. While the circulating fluid circulates through the circulating line, the polymerization of the monomer in the circulating fluid proceeds. The circulation line 2 is usually provided with supply ports for monomers and various additives (supply ports 7, 8, 9 and 10 in the form of FIGS. 1 and 2). In the present invention, a supply port for supplying a phosphorus-containing compound is essential. Such a supply port may be provided at an arbitrary position of the tank 1. Further, the supply ports 7, 8, 9 and 10 may be a common supply port. In the present invention, the circulation line 2 has at least one cooler 4. By providing the cooler 4 in the circulation line 2, a (meth) acrylic acid polymer having a narrow molecular weight distribution can be obtained. Furthermore, the tank 1 may be provided with stirring means 12. The stirring means 12 preferably stirs the circulating fluid in the tank with a required power Pv of stirring of 0.5 kW / m ³ or more. In this way, by stirring the circulating liquid in the tank with the required power of stirring above a predetermined value, a (meth) acrylic acid polymer having a narrow molecular weight distribution can be obtained more efficiently even on an industrial scale production line. Can do. The discharge line 3 discharges a part of the circulating liquid from the circulation line 2 and collects the resulting polymer. Hereinafter, the components of the (meth) acrylic acid polymer production apparatus will be described in detail. In the present specification, for convenience, the tank and the circulation line may be collectively referred to as “reaction apparatus”, and the reaction apparatus and the discharge line may be collectively referred to as “production apparatus”. Furthermore, monomers and various additives may be collectively referred to as “raw materials”.

  The circulation line 2 is configured as any appropriate piping. The material constituting the tube is preferably SUS. It is because it is excellent in heat transfer and corrosion resistance and does not affect the polymerization reaction. Specific examples include SUS304, SUS316, SUS316L, and the like. If necessary, any appropriate scale inhibitor may be applied to the inner surface of the circulation line (surface in contact with the circulating fluid).

  In the present invention, as described above, the circulation line 2 is provided with at least one cooler 4. By providing a cooler, it is possible to remove heat of reaction such as heat of polymerization, heat of dilution, heat of neutralization, heat of decomposition, heat of dissolution, etc., and make the temperature distribution in the reactor uniform, The temperature in the reactor can be easily controlled. As a result, a (meth) acrylic acid polymer having a narrow molecular weight distribution can be obtained. If the cooler is not provided, the reaction heat cannot be removed sufficiently, and the polymerization reaction may proceed rapidly. As a result, handling may be difficult. Specifically, the reaction liquid (circulating liquid) reaches the boiling point, a large amount of Michael adduct is generated, or the chain transfer agent may not function sufficiently when a chain transfer agent is used. .

  In particular, the (meth) acrylic acid polymer production apparatus used in the present invention is suitable when a monomer (for example, polymerization of (meth) acrylic acid, a salt thereof, an ester, or the like) whose polymerization reaction proceeds quickly is used. Can be applied. By providing a cooler, a sufficiently mild polymerization reaction can be achieved even in such a case. For example, depending on the reaction conditions, there may be a reaction that is fast enough that 90% or more of the monomer is converted into a water-soluble polymer in 30 seconds. Even in such a case, the polymerization reaction can be controlled by appropriately providing a cooler in the circulation line.

Any appropriate cooler can be adopted as the cooler as long as the heat of reaction can be removed by lowering the temperature of the circulating liquid passing through the cooler. The proportion of reaction heat to be removed can vary depending on the purpose and reaction system. In one embodiment, the cooler can remove 1% or more, more preferably 30% or more, still more preferably 50% or more, particularly preferably 70% or more of the generated reaction heat. By removing the reaction heat, the temperature of the circulating liquid (polymerization temperature) can be controlled within a desired range according to the purpose. If the reaction heat is not sufficiently removed, the molecular weight distribution of the resulting (meth) acrylic acid polymer may not be sufficiently narrowed. Further, in the cooler, S / V is preferably 5 or more, more preferably 6.5 or more, and particularly preferably 8 or more. Here, V is the volume of the circulating fluid (total amount of circulating fluid in the circulating line and tank) [m ³ ], and S is the heat transfer area [m ² ] of the cooler. Particularly preferably, the cooler satisfies both the reaction heat removal efficiency and the S / V. The higher the cooling efficiency of the cooler, the more preferable is that a (meth) acrylic acid polymer having a narrow molecular weight distribution can be obtained with a short residence time (that is, with very high productivity).

  The shape or type of the cooler can be appropriately set according to the purpose. Any suitable cooler or heat exchanger shape or type may be employed as the cooler shape or type. Specific examples include a multi-tube cylindrical type, a double-pipe type, a plate type, an air cooler, an irrigation cooler, a coil type, a spiral type, and a jacket. These may be employed alone or in combination. For example, in the case of a jacket or the like, the length in contact with the pipe or the tank is not particularly limited.

  The installation number and installation position of the coolers can also be appropriately set according to the purpose. For example, the number of installed coolers may be one or plural. FIG. 1 shows a case where one cooler is provided upstream of the monomer and various additive supply ports 7, 8, 9 and 10 (details will be described later) in the circulation line. FIG. 2 shows a case where one cooler is provided upstream and downstream of the monomer and various additive supply ports 7, 8, 9 and 10 (two in total). Although not shown, it goes without saying that three or more coolers may be provided. In the case where a plurality of units are installed, a plurality of units may be installed together in one circulation line. For example, they may be installed in a plurality of locations on the circulation line as shown in FIG. It is preferable to disperse and install in a plurality of places. This is because the cooling efficiency is further improved. For example, when using a monomer that generates a large amount of heat of reaction, it is particularly preferable to disperse and install a plurality of monomers. The installation position of the cooler is not limited to the illustrated example. For example, it may be provided immediately downstream of the tank outlet a, may be provided immediately upstream of the return port b, or may be provided in both of them. The cooler may be provided at least in the circulation line of the reaction apparatus. Therefore, the cooler may be provided only in the circulation line, or may be provided in both the circulation line and the tank. Preferably, the cooler is provided only in the circulation line. This is because it is not necessary to pay attention to the temperature gradient and concentration gradient of the circulating fluid in the tank (these may increase the molecular weight distribution of the resulting polymer). Even if a cooler such as a jacket or a double pipe is not provided, the temperature of the circulating fluid can be lowered to some extent by simply increasing the length of the circulation line. However, according to such means, the construction cost of the circulation line piping and device laying increases, and the pumping capacity needs to be strengthened. Furthermore, even if a very long circulation line is provided and the pumping capacity is strengthened, sufficient cooling capacity is often not obtained. As a result, the temperature gradient in the circulation line becomes large. In many cases, a polymer having these characteristics cannot be obtained. In addition, such a long circulation line has a problem that productivity is insufficient.

  As the circulation pump 6, any appropriate circulation pump can be adopted as long as the circulating liquid can be circulated to a degree sufficient to obtain a desired (meth) acrylic acid polymer. The installation position, number, type, and the like of the circulation pump can also be set appropriately according to the purpose. In the form shown in FIG. 1 and FIG. 2, one circulation pump is provided between the tank and the branch point from the circulation line to the discharge line.

  As the mixing device 5, any suitable mixing device that can make the concentration distribution of the circulating liquid uniform enough to obtain a desired (meth) acrylic acid polymer can be adopted. The installation position, number, type, and the like of the mixing device can be appropriately set according to the purpose. For example, the mixing device 5 may be provided at least in the circulation line, and thus may be provided in the tank and / or the discharge line in addition to the circulation line. Specific examples of the mixing device include a motor driven type represented by a stirring blade such as a paddle blade, Max Blend (registered trademark), an anchor blade, etc .; a surface driven type represented by a shaker, etc .; an injection collision type; an ultrasonic dispersion type A motionless mixer. Preferred are a paddle blade, Max blend, an agitation device using an anchor wing, and a motionless mixer, more preferably an agitation device using a paddle wing or an anchor wing, and a motionless mixer, and more preferably a motionless mixer. It is a mixer. By providing a motionless mixer in the circulation line, the monomer and additive (for example, polymerization initiator, chain transfer agent) in the circulation liquid are mixed efficiently, so that the concentration gradient of the circulation liquid is reduced and more There is an advantage that a uniform circulating fluid can be obtained.

  As described above, the circulation line 2 is usually provided with a supply port for monomers and various additives. In the present invention, a supply port for supplying a phosphorus-containing compound is essential. The number and installation positions of the supply ports can be appropriately set according to the type and molecular weight of the target polymer. For example, as shown in FIGS. 1 and 2, supply ports 7, 8, 9 and 10 may be provided. In one embodiment, an alkali agent or an oxidizing agent is supplied from the supply port 7, a monomer is supplied from the supply port 8, a phosphorus-containing compound is supplied from the supply port 9, and a polymerization initiator is supplied from the supply port 10. (Or polymerization accelerator) may be supplied. By providing the monomer supply port at a predetermined position in the circulation line, stirring is not necessarily required, which is very advantageous in terms of manufacturing cost of the apparatus and ease of installation. Needless to say, additives other than those described above (for example, scale inhibitors) may be supplied. Further, the supply ports 7, 8, 9 and 10 may be a common supply port. Moreover, although not shown, when the polymerization is performed in an inert gas atmosphere, such a gas inlet may be provided at an appropriate location. More specific installation forms of the monomer and additive supply ports will be described below. The monomer supply port, the polymerization initiator supply port, and other component supply ports will be described in this order.

  For example, in the form in which only one cooler as shown in FIG. 1 is provided, the monomer supply port 8 is arranged in the direction of the circulating fluid in the circulation line from the cooler to the tank as shown in FIG. Or between the tank and the cooler. When it is located between the cooler and the tank, the monomer can be supplied downstream of the cooler, so that it is easy to recover even if an unforeseen situation such as the circulation line is blocked. is there. When it is located between the tank and the cooler, there is an advantage that undesirable side reactions can be suppressed in a reaction system having a significantly large reaction heat. Further, for example, in a form in which a motionless mixer is provided in the circulation line, the monomer supply port 8 may be provided in any place of the circulation line. More specifically, the monomer supply port 8 may be provided in the motionless mixer, or may be provided between the tank and the motionless mixer in the direction of the circulating fluid in the circulation line. Well, it may be provided between the motionless mixer and the tank. Preferably, the monomer supply port is provided in the motionless mixer or between the tank and the motionless mixer. Particularly preferably, the monomer supply port is provided between the cooler and the motionless mixer in the direction of the circulating fluid flow path. By adding the monomer in or just before the motionless mixer, the supplied monomer is immediately stirred, and the concentration distribution of the monomer becomes uniform, so the molecular weight distribution is narrow (meta) An acrylic acid polymer can be obtained.

  For example, in the embodiment in which only one cooler as shown in FIG. 1 is provided, the polymerization initiator supply port 10 is connected to the tank from the cooler as shown in FIG. Or between the tank and the cooler. When it is located between the cooler and the tank, there is an advantage that the circulating fluid can be easily kept at a constant temperature when returning to the tank, and the temperature gradient can be extremely reduced. When located between the tank and the cooler, the initiator concentration is uniform in a remarkably fast reaction system, and there is an advantage that an undesired runaway reaction at the supply port can be suppressed. Further, for example, in a form in which a motionless mixer is provided in the circulation line, the polymerization initiator supply port 10 may be provided between the tank and the motionless mixer in the direction of the flow path of the circulating liquid in the circulation line. It may be provided between the motionless mixer and the tank. In any case, the circulating liquid can be sufficiently mixed by the motionless mixer.

  The relative positional relationship among the polymerization initiator supply port 10, the monomer supply port 8, the cooler 4 and the mixing device 5 is not particularly limited. For example, the polymerization initiator supply port 10 may be provided downstream of the monomer supply port 8 as shown in FIG. 1 and FIG. It may be provided. Further, in the direction of the circulating fluid in the circulation line, a polymerization initiator supply port 10 is provided downstream of the mixing device (for example, motionless mixer) 5 and a monomer supply port 8 is provided upstream of the mixing device 5. Alternatively, the polymerization initiator supply port 10 may be provided upstream of the mixing device 5 and the monomer supply port 8 may be provided downstream of the mixing device 5. Both the supply port 10 and the monomer supply port 8 may be provided upstream of the mixing device 5, and both the polymerization initiator supply port 10 and the monomer supply port 8 may be provided downstream of the mixing device 5. . Further, for example, in a mode in which only one cooler as shown in FIG. 1 is provided, the polymerization initiator supply port 10 is provided upstream of the cooler 4 and the monomer supply port 8 is provided downstream of the cooler 4. Alternatively, the polymerization initiator supply port 10 may be provided downstream of the cooler 4 and the monomer supply port 8 may be provided upstream of the cooler 4. The polymerization initiator supply port 10 and the monomer supply port 8 may be provided. Both may be provided upstream of the cooler 4, and both the polymerization initiator supply port 10 and the monomer supply port 8 may be provided downstream of the cooler 4. A preferable arrangement is that the cooler 4 / monomer supply port 8 / mixing device 5 / polymerization initiator supply port 10 and cooler 4 / monomer supply port 8 / polymerization in the flow direction of the circulating liquid in the circulation line. The initiator supply port 10 / mixing device 5 is particularly preferable, and the cooler 4 / monomer supply port 8 / polymerization initiator supply port 10 / mixing device 5 is particularly preferable. Furthermore, for example, in a form in which two coolers as shown in FIG. 2 are provided, a particularly preferable arrangement is the cooler 4 / monomer supply port 8 / mixing device 5 / polymerization initiator supply port 10 / cooler 4. It is. For example, when the viscosity of the circulating fluid is low, the monomers and the like are supplied in the above arrangement (order) so that they are mixed very quickly and the concentration gradient can be made uniform quickly. As a result, there is an advantage that a (meth) acrylic acid polymer having a very narrow molecular weight distribution can be obtained.

  In the present invention, a supply port for supplying a phosphorus-containing compound is essential. In the form shown in FIGS. 1 and 2, the phosphorus-containing compound can be supplied from the supply port 9. Preferably, the supply port is provided between the discharge line and the tank in the direction of the circulating fluid flow path. When the tank, the discharge line, and the cooler are arranged in this order in the direction of the circulating fluid in the circulation line, the supply port is preferably provided between the cooler and the tank or from the discharge line. It is provided between the coolers. When the circulation line has a motionless mixer, the supply port is preferably provided upstream of the motionless mixer in the direction of the flow path of the circulating liquid. By installing in such a position, it can be uniformly mixed with monomers and the like at an early stage by a motionless mixer.

  The number and position of the supply ports for the other components can be set appropriately according to the purpose. For example, as shown in FIGS. 1 and 2, the supply port 7 may be provided, or two or more supply ports for other components may be provided. In the form shown in FIGS. 1 and 2, an alkali agent, an oxidizing agent, or the like can be supplied from the supply port 7. Preferably, the supply port is provided between the discharge line and the tank in the direction of the circulating fluid flow path. When the tank, the discharge line, and the cooler are arranged in this order in the direction of the circulating fluid in the circulation line, the supply port is preferably provided between the cooler and the tank or from the discharge line. It is provided between the coolers. When the circulation line has a motionless mixer, the supply port is preferably provided upstream of the motionless mixer in the direction of the flow path of the circulating liquid. By installing in such a position, it can be uniformly mixed with monomers and the like at an early stage by a motionless mixer. A particularly preferable arrangement is the alkali agent supply port 7 / monomer supply port 8 / phosphorus-containing compound supply port 9 / mixing device 5 / polymerization initiator supply port 10 in the flow direction of the circulating liquid in the circulation line.

  Needless to say, the supply ports for the monomers and various additives may be provided at positions other than those described above. For example, at least one of the monomer and various additive supply ports 7, 8, 9 and 10 may be provided in the tank, may be provided immediately downstream of the tank outlet a, or immediately upstream of the tank return port b. These may be provided in combination.

  The tank 1 may have any appropriate configuration as long as the circulating fluid can be temporarily stored. For example, the material constituting the tank is the same as the circulation line. If necessary, any appropriate scale inhibitor may be applied to the inner surface of the tank (the surface in contact with the circulating fluid). Preferably, the tank not only stores and circulates the circulating liquid, but can also function as a polymerization vessel that advances the polymerization reaction of the circulating liquid. When the tank functions as a polymerization vessel (that is, by constituting a part of the reaction apparatus), the productivity of the (meth) acrylic acid polymer can be increased. Furthermore, when the production of a low molecular weight polymer is intended, the desired low molecular weight polymer can be obtained even if the concentration of the circulating liquid and the monomer supply amount are increased. In a continuous polymerization method using a conventional loop reactor (circulation line), a desired low molecular weight polymer can be obtained by increasing the concentration of circulating fluid and the amount of monomer supply in order to increase productivity. could not. On the other hand, according to the present invention, by providing a tank as a part of the reaction apparatus, a desired low molecular weight polymer can be produced with high productivity even if the concentration of the circulating liquid and the monomer supply amount are increased. Can be obtained at If necessary, the tank may be provided with a gas-liquid separator, and the circulation line may be circulated while degassing the circulating liquid.

  The tank preferably has a predetermined ratio of volume to the volume of the circulation line. More specifically, the volume of the tank is preferably 10% by volume or more, more preferably 30% by volume or more with respect to the volume of the entire circulation line. When the volume of the tank is less than 10% by volume, the piping becomes very long as a result, and pressure loss or the like may occur. As a result, the tank may not function sufficiently as a polymerization vessel, and productivity may be insufficient. On the other hand, the volume of the tank is preferably 90% by volume or less, more preferably 75% by volume or less, with respect to the volume of the entire circulation line. When the volume of the tank exceeds 90% by volume, it is necessary to increase the circulation speed very much in order to set the circulation ratio (described later) in an appropriate range. As a result, the pump needs to be large and the pressure loss may increase. Furthermore, heat removal may be insufficient. In this specification, for convenience, the tank may be referred to as a recycle tank.

  The tank and the circulation line are connected by an outlet a and a return port b. That is, the circulation line 2 exits from the outlet a of the tank 1, circulates outside the tank 1, and returns to the return port b of the tank 1. The outlet a and the return port b are provided at any appropriate place in the tank. In the example of illustration, the exit a is provided in the tank bottom part, and the return port b is provided in the tank upper part.

In the present invention, the tank 1 may be provided with stirring means 12. As the stirring means 12, any appropriate stirring means capable of stirring the circulating liquid in the tank with preferably the required power Pv of stirring of 0.5 kW / m ³ or more can be adopted. As means capable of realizing such a required power for stirring Pv, means for generating turbulent flow in the circulating liquid in the tank can be mentioned. Specific examples of the stirring means include a stirring device using a paddle type stirring blade, a saddle type stirring blade, a lattice type stirring blade, or a large flat plate blade. Specific examples of the large plate blade include a Max Blend (registered trademark) type stirring blade, a full zone type stirring blade, a supermix type stirring blade, and a Sammel type stirring blade. Moreover, you may provide a baffle plate in a normal stirring blade. By providing such a stirring means in the tank, a (meth) acrylic acid polymer having a narrow molecular weight distribution can be obtained even in an industrial scale production line. In general, the stirring device includes a drive unit, a transmission unit, and a stirring blade. The drive unit and the transmission unit may have any suitable shape and / or style as long as the desired stirring power Pv can be obtained. Specific examples of the drive unit include electric drive, hydraulic drive, and air drive (air motor). For example, the transmission unit can include an inverter and a transmission gear.

  The discharge line 3 is configured as any appropriate piping. The material which comprises a pipe | tube is the same as that of the said circulation line. The discharge line 3 may be provided at any position of the reaction apparatus. Preferably, the discharge line 3 is provided separately from the circulation line 2. This is because piping is simple, equipment is simplified, and cost is advantageous. Only one discharge line or two or more discharge lines may be provided depending on the purpose.

  The discharge line 3 is configured so that the circulation ratio is preferably 3 or more, more preferably 5 or more, still more preferably 9 or more, and particularly preferably 10 or more. When the circulation ratio is 3 or more, a (meth) acrylic acid polymer having a small concentration gradient and a narrow molecular weight distribution can be obtained with high productivity. The circulation ratio is defined by (amount of circulating liquid returning to the tank) / (amount of discharged liquid discharged from the reactor). By appropriately adjusting the circulation ratio and the cooling efficiency of the cooler, a (meth) acrylic acid polymer having a very narrow molecular weight distribution can be obtained with very high productivity. Examples of means for adjusting the circulation ratio include adjusting the discharge amount (driving force) of the pump, adjusting the opening of the circulation line and / or the discharge line, and combinations thereof.

  Preferably, the discharge line 3 has at least one cooler 4. By providing a cooler in the discharge line, the product obtained can be sufficiently removed from heat, and the apparatus can be simplified when there are post-treatments such as monomer removal and neutralization in the polymer. Specific examples of the cooler are as described above. In the form shown in FIGS. 1 and 2, the coolers are provided at two places on the discharge line.

  Preferably, the discharge line 3 has at least one mixing device. As the mixing device, a motionless mixer is preferable. By providing a mixing device (for example, a motionless mixer) in the discharge line, post-treatment such as mixing of an initiator for removing residual monomers and neutralization of a polymer can be easily performed.

  Preferably, the discharge line 3 comprises at least one monomer supply port. By providing a monomer supply port in the discharge line and mixing the discharge liquid (water-soluble polymer solution) and the monomer, the residual monomer (and the (meth) acrylic acid polymer) (and Polymerization of the added monomer) newly proceeds, and the residual monomer contained in the resulting (meth) acrylic acid polymer can be made extremely low. In the case where either a cooler or a motionless mixer is installed in the discharge line, a mode in which a monomer supply port is installed in at least one location upstream of the cooler or the motionless mixer is preferable. When both a cooler and a motionless mixer are installed, a mode in which a cooler is provided upstream of the motionless mixer and a monomer supply port is provided between the upstream cooler and the motionless mixer is preferable (FIG. 1 and FIG. FIG. 2 shows such a configuration). By arrange | positioning in this way, the reaction heat by addition of a monomer can be removed favorably, and discharge liquid can be adjusted to moderate temperature.

  The discharge line 3 may have a supply port for supplying the additive (for example, an alkali agent, a polymerization initiator or a polymerization accelerator, a phosphorus-containing compound, and an oxidizing agent) as necessary. When either a cooler or a motionless mixer is installed in the discharge line, a mode in which an additive supply port is installed in at least one location upstream of the cooler or the motionless mixer is preferable. When both the cooler and the motionless mixer are installed, it is preferable to provide a cooler upstream of the motionless mixer and provide an additive supply port between the upstream cooler and the motionless mixer. By arrange | positioning in this way, the reaction heat by addition of a polymerization initiator etc. can be removed favorably, and discharged | emitted liquid can be adjusted to moderate temperature. Such a supply port may be provided separately from the monomer supply port described above, or may also be used as the monomer supply port. When a plurality of monomer and / or additive supply ports are provided, the positional relationship can be appropriately set according to the purpose. In FIGS. 1 and 2, the monomer and / or additive supply port is shown as one “agent supply port 11” for convenience.

≪B. Continuous production method of (meth) acrylic acid polymer >>
In the method for continuously producing the (meth) acrylic acid polymer of the present invention, a circulating liquid containing a monomer component containing a (meth) acrylic acid monomer is removed from the tank 1 and The monomer is polymerized while circulating in the circulation line 2 which circulates outside and returns to the tank. Details will be described below.

  First, the monomer and various additives (for example, an alkali agent, a polymerization initiator or a polymerization accelerator, a phosphorus-containing compound, an oxidizing agent, a crosslinking agent, etc.) are added to the manufacturing apparatus described in the above section A. Supply. The supply order of monomers and additives can be appropriately set according to the type of polymer, molecular weight, molecular weight distribution, and the like. For example, by supplying an alkali agent or an oxidant, the pH of the circulating liquid can be adjusted, and the monomer can be partially or completely neutralized; by using a polymerization accelerator, a polymerization reaction can be performed. The molecular weight distribution of the resulting water-soluble polymer can be narrowed; by using a phosphorus-containing compound, the polymerization reaction can be controlled and the molecular weight distribution of the resulting water-soluble polymer can be narrowed. In addition, it is possible to obtain a polymer in which the dispersibility of the calcium carbonate slurry is very excellent. In the embodiment using the production apparatus shown in FIGS. 1 and 2, the alkali agent, the monomer, the phosphorus-containing compound, and the polymerization initiator can be supplied in this order while circulating the circulating liquid in a steady state. Examples of a method for supplying the monomer or the like to the tank include a method using a metering pump or the like while using a back pressure valve to prevent the circulating fluid from flowing backward. The amount of each additive added to the monomer can be appropriately set according to the purpose. Details of the monomer and various additives will be described in Section C below.

  As a supply form of the monomer and various additives, any appropriate supply form can be adopted as long as the effects of the present invention are obtained. In one embodiment, the monomer and various additives can be dissolved in an appropriate solvent in advance (for example, a solvent described in Section C below) and supplied as a solution to the circulation line. The concentration of such a solution can be appropriately set according to the type and molecular weight of the target polymer. In one embodiment, the monomer and various additives can be supplied to the circulation line under temperature control within an appropriate range. The temperature of the monomer or the like can be appropriately set according to the desired circulating fluid temperature (polymerization temperature) or the like. A monomer and various additives may be supplied continuously, may be supplied collectively, and may be supplied by dividing | segmenting intermittently. In the case of continuous supply, the supply amount per unit time may be constant, may be gradually increased or decreased, or may be changed stepwise. Furthermore, the supply amount per unit time can be increased or decreased according to the purpose. Needless to say, the supply forms described above may be combined as appropriate. In the case of producing a copolymer, a plurality of monomers may be supplied all at once or sequentially. The supply order in the case of supplying sequentially may be appropriately set according to the purpose (for example, a desired structure of the copolymer).

  The total amount of monomers and various additives supplied to the circulation line is preferably 0.1 to 50% by weight, more preferably 0.5%, based on the total amount of circulating liquid in the circulation line. ~ 20% by weight. By controlling the supply amount in such a range, a water-soluble polymer having a narrow molecular weight distribution and few residual monomers can be obtained with high productivity. The flow rate of the circulating fluid can be appropriately set according to the purpose and the scale (production capacity) of the manufacturing apparatus. The flow rate of the circulating liquid may be constant or may be changed continuously or stepwise as the polymerization proceeds. The flow rate (or flow rate) of the circulating fluid can be appropriately set by the manufacturing apparatus. For example, when the total amount of the circulating fluid is 85 kg, the flow rate of the circulating fluid is preferably 1700 kg / h or more.

  In the method for continuously producing the (meth) acrylic acid polymer of the present invention, it is important to supply 3 to 7 g of the phosphorus-containing compound with respect to 1 mol of the (meth) acrylic acid monomer. By supplying a predetermined amount of the phosphorus-containing compound as described above, the effects of the present invention are sufficiently exhibited. In particular, it is possible to produce a (meth) acrylic acid polymer having a very excellent dispersibility of the calcium carbonate slurry and a narrow molecular weight distribution. The supply amount of the phosphorus-containing compound with respect to 1 mol of the (meth) acrylic acid monomer is preferably 3.1 to 6.5 g, more preferably 3.2 to 6.3 g. The phosphorus-containing compound referred to in the present invention may be any appropriate phosphorus-containing compound as long as it is a compound containing a phosphorus atom and can function as a chain transfer agent. Particularly preferred phosphorus-containing compounds in the present invention are hypophosphorous acid and hypophosphite (for example, sodium hypophosphite).

  In the method for continuously producing the (meth) acrylic acid polymer of the present invention, the circulating liquid is cooled in at least one position of the circulating line. The preferred cooling position (cooler installation position) in the circulation line is as described in the above section A. By performing such a cooling treatment, the heat of reaction can be efficiently removed, so that the monomer can be polymerized at a high polymerization concentration. As a result, the time during which the circulating liquid stays in the reaction apparatus can be shortened, so that a (meth) acrylic acid polymer can be obtained with very high productivity. The residence time will be described later.

  In one embodiment, the liquid temperature (polymerization temperature) of the circulating liquid in the said circulation line is 25-150 degreeC. The polymerization temperature is preferably 50 ° C. or higher, more preferably 70 ° C. or higher. The polymerization temperature is preferably 130 ° C. or lower, more preferably 99 ° C. or lower, and can be lower than 95 ° C. When the polymerization temperature is within such a range, sufficient productivity can be achieved with an appropriate polymerization time without causing an increase in molecular weight or an increase in impurities. When a polymerization initiator is used, the polymerization temperature can vary depending on the half-life of the polymerization initiator. For example, the polymerization temperature in the case of using a polymerization initiator is preferably 60 to 130 ° C, more preferably 70 to 120 ° C, and further preferably 80 to 120 ° C. In the production method of the present invention, the temperature of the circulating liquid can be efficiently controlled within a desired range by performing cooling at an appropriate position in the circulation line. As a result, there is an advantage that an inexpensive general-purpose polymerization initiator can be used. The temperature of the circulating fluid stored in the tank is also preferably in the above range. The polymerization temperature may be changed over time (increase or decrease in temperature) within a predetermined range as necessary.

  The polymerization temperature is preferably controlled within a predetermined range in the circulation line. For example, the difference between the temperature of the circulating fluid at the inlet of the circulation line (the outlet a of the tank 1) and the temperature of the circulating fluid at the outlet of the circulation line (the return port b of the tank 1) is preferably within 25 ° C. Preferably it is within 20 degreeC, More preferably, it is within 18 degreeC. By controlling the fluctuation range in the circulation line within such a range, a (meth) acrylic acid polymer having a narrow molecular weight distribution can be obtained. Further, when a polymerization initiator is used, the decomposition rate can be made almost constant, so that a uniform polymerization reaction can be performed. The temperature of the circulating liquid at the inlet and outlet of the circulation line is preferably 10 to 90 ° C. Thereby, heat can be stably removed from the circulating fluid. This temperature can be controlled by appropriately setting the solution flow rate and the temperature of the cooling medium in the production apparatus.

Examples of the method for controlling the desired polymerization temperature and fluctuation range include feedback control in which the temperature of the circulating liquid is detected by a temperature sensor and the setting of the cooler is adjusted according to the detected value. For example, when the target polymerization temperature is T ° C., the control range is preferably T ° C. ± 10 ° C., more preferably T ° C. ± 7 ° C., and further preferably T ° C. ± 5 ° C. The temperature control by this feedback control can be more effective as the scale of the manufacturing apparatus (particularly the tank) is larger. This is because heat dissipation from the tank surface is reduced, and in particular, an effect of heat removal by the circulation line is likely to appear. Specifically, the volume of the production apparatus (tank) is preferably 1 m ³ or more, more preferably 3 m ³ or more, and further preferably 5 m ³ or more. In addition, when it is necessary to keep the circulating fluid warm, any appropriate means can be used. For example, controlling the temperature of the heat medium (or refrigerant) flowing in the jacket of the motionless mixer, adjusting the monomer supply amount, keeping the pipes and tanks warm (wrapping a heat insulator, etc.), circulation lines and tanks Supply of heat to

  As described above, according to the method for continuously producing the (meth) acrylic acid polymer of the present invention, the monomer can be polymerized at a high polymerization concentration, and no aging step is required. The residence time of the liquid in the reactor can be shortened (that is, the monomer can be polymerized in a short polymerization time). Here, the residence time refers to the total amount of circulating fluid / the discharge amount per unit time. The residence time is preferably 240 minutes or less, more preferably 180 minutes or less, still more preferably 120 minutes or less, and particularly preferably 90 minutes or less. On the other hand, the residence time is preferably 3 minutes or more. According to the method for continuously producing the (meth) acrylic acid polymer of the present invention, a (meth) acrylic acid polymer having a narrow molecular weight distribution can be obtained very efficiently with such a short residence time. it can. Furthermore, a (meth) acrylic acid polymer excellent in various properties such as clay dispersibility can be obtained. Note that, when the residence time is shortened, the productivity is increased while the heat of reaction per unit time is increased. The method for continuously producing the (meth) acrylic acid polymer of the present invention can reduce the temperature gradient in the reaction system by performing the appropriate cooling treatment as described above. Production with a short residence time can be realized.

  In the method for continuously producing the (meth) acrylic acid polymer of the present invention, it is particularly preferable that the temperature fluctuation (temperature difference between the tank outlet and the return port) is small and the residence time is short. For example, the combination of temperature fluctuation / residence time is preferably within 25 ° C./180 minutes or less, more preferably within 20 ° C./120 minutes or less, even more preferably within 20 ° C./90 minutes or less, particularly Preferably, it is within 15 ° C./90 minutes or less.

  In the method for continuously producing the (meth) acrylic acid polymer of the present invention, the monomer conversion rate is preferably 90% or more, more preferably 96% or more, and even more preferably 99%. % Or more. If the conversion is less than 90%, there are many residual monomers and the productivity may be reduced. Here, the conversion rate refers to the amount of monomer converted into a polymer at the circulation line outlet (tank inlet) with respect to the amount of monomer added at the monomer supply port. The conversion rate can be obtained by changing the amount of initiator, amount of transfer agent, amount of accelerator, temperature, residence time in various ways, for example, when sodium acrylate is used as a monomer to obtain sodium polyacrylate (PSA). It can be calculated based on the Arrhenius equation from the result of the simulation by the reaction rate analysis. Note that the conversion rate by the above calculation method is as follows when a copolymer such as (meth) acrylic acid (salt) / (meth) acrylic acid ester is produced in a continuous stirred tank reactor (CSTR). , PSA and other homopolymers may be different, but the preferred range of conversion is as described above.

In the method for continuously producing the (meth) acrylic acid polymer of the present invention, the circulating liquid in the tank is preferably stirred with a required power Pv of stirring of 0.5 kW / m ³ or more. The required power Pv for stirring is more preferably 0.6 to 8.0 kW / m ³ , and further preferably 1.0 to 6.0 kW / m ³ . By stirring the circulating liquid in the tank with the power required for stirring in such a range, a (meth) acrylic acid polymer having a narrow molecular weight distribution can be obtained even on an industrial scale production line. Although even if the agitation power Pv greater than 8.0 kW / m ³ it is possible to obtain the desired stirring conditions, the effect obtained in the case of the preferred range substantially unchanged, economy (e.g. In view of the fact that it takes electric power and operating costs, and that the apparatus needs to be enlarged, it may not be adopted. The required stirring power Pv can be calculated, for example, from the Nagata equation described on page 431 of the Chemical Engineering Handbook (Edited by the Chemical Engineering Society, revised 6th edition, Maruzen Co., Ltd.).

  In the method for continuously producing the (meth) acrylic acid polymer of the present invention, the monomer concentration of the circulating liquid at the tank outlet is preferably 0.3 mol / kg or less, more preferably 0.8. 15 mol / kg or less, more preferably 0.10 mol / kg or less. The monomer concentration of the circulating liquid at the tank outlet is preferably as small as possible, and particularly preferably substantially 0 mol / kg. By controlling to such a concentration, the residual monomer of the finally obtained product can be made extremely low. According to the method for continuously producing the (meth) acrylic acid polymer of the present invention, such a monomer concentration can be achieved by the tank also functioning as a polymerization vessel.

  In the method for continuously producing the (meth) acrylic acid polymer of the present invention, the polymerization reaction in the tank and / or the circulation line may be performed under pressure. By performing the polymerization reaction under pressure, the polymerization reaction can be performed at a high temperature. As a result, a (meth) acrylic acid polymer with little residual monomer can be obtained with very high productivity. The pressure may be controlled, for example, by adjusting the flow rate or temperature of the circulating fluid, or may be controlled using pressure control means such as a pressure pump or a pressure reduction pump. The pressure in the tank and / or the circulation line is preferably 0.1 MPa to 3.0 MPa, more preferably 0.12 MPa to 1.0 MPa. The polymerization reaction can be performed under any appropriate atmosphere (for example, under air, under an inert gas atmosphere such as nitrogen or argon, under a reactive gas atmosphere derived from a chain transfer agent, etc.).

  In the method for continuously producing the (meth) acrylic acid polymer of the present invention, the polymerization reaction can be performed in any appropriate pH range. In other words, the polymerization reaction may be performed under acidic conditions, may be performed under neutral conditions, or may be performed under alkaline conditions. For example, when persulfate is used as the polymerization initiator, it is preferably carried out under low pH conditions, and when hydrogen peroxide is used, it is preferably carried out under high pH conditions. For example, when the polymerization reaction is carried out in an acidic region, an increase in the viscosity of the aqueous solution of the polymerization reaction system can be suppressed, and a low molecular weight (meth) acrylic acid polymer can be produced favorably. The pH of the circulating fluid can be adjusted by appropriately using an oxidizing agent or an alkaline agent.

  As described above, in the method for continuously producing the (meth) acrylic acid polymer of the present invention, the supplied monomer is converted into a polymer at a very high conversion rate while circulating in the circulation line. is doing. Therefore, the discharged liquid ((meth) acrylic acid polymer solution) can be recovered by discharging a part of the circulating liquid to the outside of the circulation line while circulating the circulating liquid. Usually, the effluent can be post-treated. In this specification, “post-treatment” means that the (meth) acrylic acid polymer in the discharged liquid is suitably used for a predetermined application (for example, a dispersant, a detergent composition, a water treatment agent, a scale inhibitor). In order to be able to do this, it refers to various treatments performed on the (meth) acrylic acid polymer. Hereinafter, typical post-processing will be described in detail.

  In one embodiment, the effluent may be supplied with the monomer and, if necessary, the various additives. Polymerization of residual monomer (and added monomer) contained in (meth) acrylic acid polymer by mixing waste liquid (solution of (meth) acrylic acid polymer) and monomer Newly proceed and the residual monomer contained in the resulting (meth) acrylic acid polymer can be made extremely low. In one embodiment, mixing (typically agitation) and / or cooling can occur at an appropriate location in the discharge line. The mixing device and the cooler are as described in the above section A.

  In one embodiment, the additive can be an oxidizing agent. By supplying the oxidizing agent, the pH of the effluent is adjusted, and new polymerization of the residual monomer can proceed well. Therefore, the oxidizing agent can be preferably supplied before supplying the monomer. The kind of the oxidizing agent to be supplied can be appropriately selected according to the kind of the polymerization initiator, the components in the discharged liquid, and the like.

  The various post-treatments described above can be performed in appropriate combination.

  The solid content concentration of the discharged liquid at the time when the discharged liquid is recovered from the discharge line (at the time when the polymerization reaction is completed) is preferably 35% by mass or more, more preferably 40 to 70% by mass, and further preferably 45 to 65% by mass. It is. When the solid content concentration is less than 35% by mass, for example, it may be necessary to concentrate the effluent for practical use of the (meth) acrylic acid polymer. According to the method for continuously producing the (meth) acrylic acid polymer of the present invention, the polymerization can be carried out in such a high concentration (high solid content concentration) and in a single stage, so that the low molecular weight (meth) An acrylic acid polymer can be obtained efficiently. For example, the above-described concentration step (which was necessary in many cases in the conventional manufacturing method) can be omitted. As a result, the production efficiency and production cost of the (meth) acrylic acid polymer can be greatly improved. Furthermore, in the conventional method, when the solid content concentration is increased, the viscosity of the reaction solution is significantly increased with the progress of the polymerization reaction, and the weight average molecular weight of the resulting (meth) acrylic acid polymer is significantly increased. The problem that occurred. According to one embodiment of the method for continuously producing the (meth) acrylic acid polymer of the present invention, the polymerization reaction is carried out under acidic conditions (for example, the pH at 25 ° C. is 1 to 6, When the degree of harm is in the range of 0 to 25 mol%, an increase in the viscosity of the reaction solution (circulated liquid and / or discharged liquid) accompanying the progress of the polymerization reaction can be suppressed. As a result, a (meth) acrylic acid-based polymer having a high concentration (high solid content concentration) and a low molecular weight can be obtained.

  If necessary, any appropriate alkaline agent is added to the recovered effluent (the solution of the desired (meth) acrylic acid polymer) to obtain a desired degree of neutralization (final neutralization degree). Can be adjusted to range. An alkali agent may be used independently according to the objective, and may be used in combination of 2 or more type. The desired degree of final neutralization varies depending on the use of the water-soluble polymer. Therefore, the final neutralization degree can be set in a very wide range of 0 to 100 mol%. For example, in the case of using (meth) acrylic acid polymer as a detergent builder for weakly acidic detergents that are said to be gentle to the skin, even if the acid is used without neutralizing the effluent. Good. The final neutralization degree when used as an acidic polymer is preferably 0 to 75 mol%, more preferably 5 to 70 mol%. Further, for example, when used in a neutral detergent or an alkaline detergent, the discharged liquid may be neutralized with an alkaline agent and neutralized to a degree of neutralization of 90 mol% or more. When used as a neutral to alkaline polymer, the final neutralization degree is preferably 75 to 100 mol%, more preferably 85 to 99 mol%. Although there may be no problem depending on the application, when the final neutralization degree exceeds 99 mol%, the discharged liquid ((meth) acrylic acid polymer solution) may be colored.

  As described above, the (meth) acrylic acid polymer is produced.

≪C. (Meth) acrylic acid polymer and its raw material >>
C-1. (Meth) acrylic acid polymer When the (meth) acrylic polymer of the present invention is used as a dispersant, detergent composition, water treatment agent, scale inhibitor, etc., its weight average molecular weight (Mw) is , Preferably it is 1500-30000, More preferably, it is 2000-20000, More preferably, it is 3500-15000, Most preferably, it is 4000-12000. When the (meth) acrylic acid polymer of the present invention is a homopolymer of (meth) acrylic acid (salt), its weight average molecular weight (Mw) is preferably 1500 to 30000, more Preferably it is 2000-12000, More preferably, it is 2000-10000. By narrowing the molecular weight distribution (Mw / Mn) in such a molecular weight range, more polymers having the same degree of polymerization can be obtained. As a result, for example, the dispersant has a favorable influence on the performance required for each application, such as improvement of dispersibility. Mw / Mn is preferably 7 or less, more preferably 5 or less, still more preferably 3.5 or less, particularly preferably 3.2 or less, and most preferably 2.8 or less.

  The number average molecular weight (Mn), weight average molecular weight (Mw) and Mw / Mn of the (meth) acrylic acid polymer of the present invention can be obtained by GPC (gel permeation chromatography) measurement. Measurement conditions are as follows: (1) As a GPC column, G-3000PWXL (trade name) manufactured by Tosoh Corporation is used. (2) As a mobile phase, 34.5 g of disodium hydrogen phosphate 12 hydrate and 46.2 g of sodium dihydrogen phosphate dihydrate (both of which are reagent-grade) are added pure water to make a total amount of 5000 g, Thereafter, an aqueous solution (solid content: 0.1% by mass) filtered through a 0.45 μm membrane filter is used. (3) As the detector, L-7110 (trade name) manufactured by Hitachi, Ltd. is used, and the detection wavelength is 214 nm. (4) Measurement is performed in the UV measurement mode. (5) The pump is L-6000 manufactured by Hitachi, Ltd., the mobile phase flow rate is 0.5 ml / min, and the temperature is 35 ° C. (6) A calibration curve is prepared using a sodium polyacrylate standard sample manufactured by Soka Kagaku Co., Ltd., and the molecular weight is calculated using analysis software SIC480II data station manufactured by System Instruments Co., Ltd.

  In this specification, the (meth) acrylic acid polymer is a simple substance that essentially includes at least one selected from acrylic acid, methacrylic acid, acrylate, methacrylate, acrylate, and methacrylate. It means a polymer obtained by polymerizing a monomer component. Examples of the salt include alkali metal salts such as sodium and potassium; alkaline earth metal salts such as calcium and magnesium; ammonium salts; organic amine salts such as monoethanolamine and triethanolamine. These salts may be used alone or as a mixture of two or more. The preferred form in the case of a salt is an alkali metal salt such as sodium or potassium and an ammonium salt, and particularly preferably a sodium salt or an ammonium salt.

  The (meth) acrylic acid polymer of the present invention has a phosphorus atom at the end of the main chain and inside the main chain. The phosphorus atom is derived from a phosphorus-containing compound used during production. In the (meth) acrylic acid polymer of the present invention, the ratio of the amount of phosphorus atoms inserted into the main chain to the amount of phosphorus atoms arranged at the end of the main chain is preferably a molar ratio, preferably 3 or more, more preferably 3.5 or more, and particularly preferably 4 That's it. The upper limit of the ratio of the phosphorus atom weight inserted into the main chain to the phosphorus atom weight arranged at the end of the main chain is preferably 50 or less, more preferably 30 or less, and particularly preferably 20 or less, in molar ratio. In the (meth) acrylic acid polymer of the present invention, when the ratio of the main chain internal insertion phosphorus atom weight to the main chain terminal arrangement phosphorus atom weight is in the above range in terms of molar ratio, the dispersibility of the calcium carbonate slurry is very excellent, and the molecular weight Narrow distribution, can exhibit exceptional performance when used in dispersants, detergent compositions, water treatment agents, scale inhibitors, etc., and can be manufactured with high efficiency on an industrial scale (meta) An acrylic acid polymer can be provided.

In the (meth) acrylic acid polymer of the present invention, the form having a phosphorus atom in the main chain can be expressed by the following general formula when the polymer main chain of the polymer is represented by A.
AP (= O) (OX) -A
X represents a hydrogen atom; an alkali metal such as sodium or potassium; an alkaline earth metal such as calcium or magnesium; an ammonium; an organic amine such as monoethanolamine or triethanolamine; X is preferably an alkali metal such as sodium or potassium and ammonium, and particularly preferably sodium and ammonium.

In the (meth) acrylic acid polymer of the present invention, the form having a phosphorus atom at the end of the main chain can be expressed by the following general formula when the polymer main chain of the polymer is represented by A.
AP (= O) (OX) -H
Or A-P (= O) (OX) -OX
X represents a hydrogen atom; an alkali metal such as sodium or potassium; an alkaline earth metal such as calcium or magnesium; an ammonium; an organic amine such as monoethanolamine or triethanolamine; X is preferably an alkali metal such as sodium or potassium and ammonium, and particularly preferably sodium and ammonium.

  The peak top molecular weight of the (meth) acrylic acid polymer of the present invention is preferably in the range of 100 to 50,000. In addition, the (meth) acrylic acid polymer of the present invention is gel permeation chromatography with a molecular weight obtained from a calibration curve using standard sodium polyacrylate from 2500 to 7000. The area strength of the included section is preferably 38.0% or more, more preferably 39.0% or more, and more preferably, with respect to the total area strength of the (meth) acrylic acid polymer. 39.5% or more, particularly preferably 40.0% or more, and most preferably 41.0% or more. The (meth) acrylic acid polymer of the present invention is included in the retention time when the molecular weight obtained from the calibration curve using standard sodium polyacrylate is 2500 to the retention time of 7000 by gel permeation chromatography. The area strength of the section is preferably 100% or less, more preferably 95.0% or less, and further preferably 90.0% or less, with respect to the total area strength of the (meth) acrylic acid polymer. It is particularly preferably 85.0% or less, and most preferably 80.0% or less.

  The ratio of the above area strengths is an area ratio obtained by gel permeation chromatography (GPC), which is 7000 from the retention time when the molecular weight obtained from the calibration curve using standard sodium polyacrylate is 2500. The area strength of polyacrylic acid and / or its salt in the section included in the holding time] / [total area strength of (meth) acrylic acid polymer] × 100. When the retention time is less than 2500, the resulting (meth) acrylic acid polymer has low dispersibility, and when the retention time exceeds 7000, when a metal atom coexists, the metal atom is crosslinked, There is a possibility that it becomes insolubilized and cannot be suitably used for various applications described later. As the area ratio, for example, as shown in the conceptual diagram of FIG. 3, the mesh portion has a retention time from which the molecular weight obtained from a calibration curve using standard sodium polyacrylate is 2500 to 7000. The area strength of the (meth) acrylic acid polymer in the section contained in the graph is shown, and the hatched portion represents the total area strength of the (meth) acrylic acid polymer.

  The measurement conditions for the gel permeation chromatography (GPC) are preferably as described above. The standard curve using standard sodium polyacrylate is the same as the GPC measurement conditions of standard polysodium acrylate having a peak top molecular weight (Mp) of 900 to 47500, for example. It is measured under conditions and represents the relationship between retention time and molecular weight. The area intensity of the (meth) acrylic acid polymer is obtained by dividing the area of the section corresponding to Mp of 2500 to 7000 by the area of the entire section from the calibration curve.

  The (meth) acrylic acid polymer of the present invention may contain other components other than the polymer component. Examples of the other components include organic substances / inorganic substances derived from initiators / transfer agents, residual monomers and addition reaction products derived from residual monomers. As a content rate of the said polymer component, it is preferable that it is 90 mol or more in 100 mol of (meth) acrylic-acid type polymers. There exists a possibility that the effect of this invention cannot fully be exhibited as it is less than 90 mol. More preferably, it is 95 mol or more, More preferably, it is 100 mol%.

  The (meth) acrylic acid polymer of the present invention preferably has a clay dispersibility of 0.85 or more. If it is less than 0.85, it may not be suitably used for various applications such as a dispersant, a detergent composition, a water treatment agent, and a scale inhibitor. More preferably, it is 0.88 or more, More preferably, it is 0.90 or more.

C-2. Monomer Component In the present invention, as the monomer component, any appropriate monomer component can be used as long as it is a monomer component containing a (meth) acrylic acid monomer.

  The content ratio of the (meth) acrylic acid monomer in the monomer component is preferably 50 to 100 mol%, more preferably 70 to 100 mol%, still more preferably 90 to 100 mol%, particularly preferably. It is 95-100 mol%, Most preferably, it is 100 mol%. When the content ratio of the (meth) acrylic acid monomer in the monomer component is in the above range, the effect of the present invention can be sufficiently exhibited.

  The (meth) acrylic acid monomer is preferably at least one selected from acrylic acid, methacrylic acid, acrylate, methacrylate, acrylate, and methacrylate. Examples of the salt include alkali metal salts such as sodium and potassium; alkaline earth metal salts such as calcium and magnesium; ammonium salts; organic amine salts such as monoethanolamine and triethanolamine. These salts may be used alone or as a mixture of two or more. The preferred form in the case of a salt is an alkali metal salt such as sodium or potassium and an ammonium salt, and particularly preferably a sodium salt or an ammonium salt. The said (meth) acrylic-acid type monomer may be used only 1 type, and may use 2 or more types together.

  In the present invention, examples of the monomer that can be contained in the monomer component other than the (meth) acrylic acid monomer include unsaturated carboxylic acids other than the (meth) acrylic acid monomer. An acid monomer (hereinafter also referred to as monomer (I)), the above (meth) acrylic acid monomer and other monomers copolymerizable with monomer (I) (hereinafter referred to as “monomer (I)”) , Also referred to as monomer (II)). The monomer (I) may be used alone or in combination of two or more. The monomer (II) may be used alone or in combination of two or more.

The monomer (I) may be any monomer having a polymerizable unsaturated group and a group capable of forming a carbanion other than the (meth) acrylic acid monomer. It is a compound represented by General formula (1).

^Wherein, R 1, ^{R 2} and ^{R 3} are the same or different, a hydrogen atom, a methyl group, or _- represents a ^{_{(CH 2) z1 COOM 2,}} z1 represents the number of 0 to 3. - _{(CH 2)} z1 COOM ² may, -COOM ¹ or another _{- (CH} 2) may form a z1 COOM ² and anhydride. M ¹ and M ² are the same or different and each represents a hydrogen atom, a metal atom, an ammonium group, or an organic amine group (organic ammonium group). However, the case where the compound represented by the general formula (1) is a (meth) acrylic acid monomer is excluded.

The metal atom in M ¹ and M ² of the general formula (1) is a monovalent metal atom such as an alkali metal atom such as lithium, sodium or potassium; a divalent metal such as an alkaline earth metal atom such as calcium or magnesium; A trivalent metal atom such as aluminum or iron is preferred. Moreover, as an organic amine group, alkanolamine groups, such as an ethanolamine group, a diethanolamine group, and a triethanolamine group, and a triethylamine group are suitable. Further, the organic amine group may be an ammonium group.

  As said monomer (I), unsaturated monocarboxylic acid-type monomers other than (meth) acrylic acid-type monomers, unsaturated dicarboxylic acid-type monomers, etc. are suitable. The unsaturated monocarboxylic acid-based monomer other than the (meth) acrylic acid-based monomer may be any monomer having one unsaturated group and one group capable of forming a carbanion in the molecule. For example, crotonic acid, α-hydroxyacrylic acid, etc .; these monovalent metal salts, divalent metal salts, ammonium salts, and organic amine salts are preferred. The unsaturated dicarboxylic acid monomer may be any monomer having one unsaturated group and two groups capable of forming a carbanion in the molecule. Maleic acid, itaconic acid, citraconic acid, fumaric acid Acids, etc., their monovalent metal salts, divalent metal salts, ammonium salts, organic amine salts, etc., or their anhydrides are preferred.

  The monomer (I) also includes a half ester of an unsaturated dicarboxylic acid monomer and an alcohol having 1 to 22 carbon atoms, a half amide of an unsaturated dicarboxylic acid and an amine having 1 to 22 carbon atoms, A half ester of an unsaturated dicarboxylic acid monomer and a glycol having 2 to 4 carbon atoms, a half amide of maleamic acid and a glycol having 2 to 4 carbon atoms, or the like can also be used.

  Examples of the monomer (II) include vinyl sulfonic acid, allyl sulfonic acid, 3-allyloxy-2-hydroxypropane sulfonic acid, isoprene sulfonic acid, 2-acrylamidomethylpropane sulfonic acid, styrene sulfonic acid, and 2-sulfo. Monoethylenically unsaturated monomers having a sulfonic acid group such as ethyl methacrylate, and partial or completely neutralized salts thereof such as monovalent metal salts, divalent metal salts, ammonium salts, and organic amine salts; Unsaturated carbonization containing hydroxyl groups such as methyl-2-buten-1-ol (simply also referred to as prenol), 3-methyl-3-buten-1-ol (simply also referred to as isoprenol), (meth) allyl alcohol, etc. Unsaturated polyalkylene glycos with addition of alkylene oxide to hydrogen and isoprenol or allyl alcohol It can be exemplified Le-based monomers and the like.

  As said monomer (II), a radically polymerizable monomer can also be used conveniently. As the radically polymerizable monomer, when the (meth) acrylic acid monomer is at least one selected from acrylic acid, methacrylic acid, acrylate, and methacrylate, for example, (meth) Methyl acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, tridecyl (meth) acrylate, (meth ) Stearyl acrylate, cyclohexyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, ethylaminoethyl (meth) acrylate, glycidyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, (meth) acrylic Mono (meth) acrylates such as allyl acid; triethylene glycol di ( Acrylate), tetraethylene glycol di (meth) acrylate, pentyl glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, trimethylolpropane di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol Poly (meth) acrylates such as tri (meth) acrylate and pentaerythritol tetra (meth) acrylate; (meth) acrylates such as; alkoxy polyalkylene glycol (meth) acrylate; polyalkylene glycol (meth) acrylate; α- (Hydroxyalkyl) acrylic acid (salt); α- (hydroxypolyalkyleneoxymethyl) acrylic acid (salt);

  Examples of the radical polymerizable monomer include aromatic monomers such as styrene and α-methylstyrene; vinyl esters such as vinyl acetate and vinyl propionate; hydroxymethyl vinyl ether, hydroxyethyl vinyl ether, hydroxy Vinyl ethers such as propyl vinyl ether and hydroxybutyl vinyl ether; monomers having a nitrogen-containing functional group such as N-vinylpyrrolidone and acryloylmorpholine; nitrile group-containing monomers such as (meth) acrylonitrile; (meth) acrylamide, N- Amide monomers such as methylolacrylamide; carboxyl group-containing monomers such as itaconic acid, crotonic acid, maleic anhydride, and maleic acid; hydroxyl group-containing monomers such as 2-hydroxyethyl (meth) acrylate; (Meth) acrylic acid Epoxy group-containing monomers such Rishijiru; and the like.

  In the present invention, the (meth) acrylic acid monomer, monomer (I), and monomer (II) in the monomer component are each dissolved in a solvent described later, preferably water. It may be added in the form of a solution (preferably an aqueous solution).

  Examples of the solvent include water; monohydric alcohols such as methanol, ethanol, propanol, isopropyl alcohol, butanol, pentanol, hexanol, cyclohexanol, methylcyclohexanol, and benzyl alcohol; ethylene glycol, propylene glycol, ethylene glycol diacetate, Ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, diethylene glycol, diethylene glycol diacetate, propylene glycol monomethyl Ether, propire Polyhydric alcohols such as glycol monoethyl ether, propylene glycol monobutyl ether, propylene glycol monomethyl ether acetate and glycerin and derivatives thereof; Amides such as dimethylformaldehyde; Ethers such as diethyl ether and dioxane; Acetone, methyl ethyl ketone, diisobutyl ketone and diisopropyl Ketone solvents such as ketone, diethyl ketone, cyclohexanone, methyl isobutyl ketone; ester solvents such as methyl acetoacetate, ethyl acetoacetate, methyl benzoate, ethyl benzoate, ethyl acetate, butyl acetate; benzene, toluene, xylene, cyclohexane Hydrocarbon solvents such as; and the like. The said solvent may use only 1 type and may use 2 or more types together.

  The solvent is preferably an aqueous solvent such as water, alcohol, glycol, glycerin or polyethylene glycol. More preferably, the aqueous solvent uses water and one or more kinds other than water. When a solvent other than water is used, the boiling point or solubility can be adjusted. The mixing ratio of water and a solvent other than water may be appropriately set in consideration of the solubility of the polymer, the reactivity with the raw materials, and the like, and is usually preferably 10% by weight or less.

  The amount of the solvent used is preferably 40 to 200% by weight, more preferably 45 to 180% by weight, and still more preferably 50 to 150% by weight, based on the total amount of the monomer components. When the amount of the solvent used is less than 40% by weight, the molecular weight becomes high. On the other hand, when the amount of the solvent used exceeds 200% by weight, the produced (meth) acrylic acid polymer This is not preferable because the concentration of the solution becomes low and, in some cases, solvent removal is required. A part of the solvent can be charged into the production apparatus at the initial stage of polymerization as required. A part of the solvent may be appropriately added to the reaction system alone during polymerization, for example, from the supply port of other components. In addition, monomer components, initiators, other additives, and the like may be appropriately added to the reaction system during the polymerization together with these components in the form of being dissolved in a solvent in advance.

  The amount ratio of the solvent and the monomer component is preferably, for example, 200 parts by weight or less based on 100 parts by weight of the solvent. More preferably, it is 180 weight part or less, More preferably, it is 160 weight part or less.

  In the case of copolymerization, the addition time may be controlled according to the polymerizability of each monomer contained in the monomer component. For example, when using a monomer having low polymerizability, the addition time may be shortened. Further, a part or the whole amount of the monomer may be charged in the production apparatus in advance.

C-3. Polymerization initiators As the polymerization initiator that can be used in the production method of the present invention, persulfates, redox initiators, azo initiators, organic peroxides, and photoinitiators are suitable. Specifically, for example, persulfates such as sodium persulfate, ammonium persulfate, and potassium persulfate; hydrogen peroxide; 2,2′-azobis (2-amidinopropane) dihydrochloride, 4,4′-azobis ( Azo compounds such as 4-cyanovaleric acid), azobisisobutylnitrile, 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile); benzoyl peroxide, lauroyl peroxide, peracetic acid, persuccinic acid , Organic peroxides such as di-t-butyl peroxide, t-butyl hydroperoxide, cumene hydroperoxide, and the like. Among these, redox initiators, azo initiators, and organic peroxides are preferable. Specifically, for example, persulfate, hydrogen peroxide, organic peroxide, 2,2′-azobis (2-amidinopropane) dihydrochloride is preferable, and persulfate, hydrogen peroxide, 2,2 ′. -Azobis (2-amidinopropane) dihydrochloride is more preferred, and persulfate and hydrogen peroxide are more preferred. Only 1 type may be used for a polymerization initiator and it may use 2 or more types together.

  As said polymerization initiator, you may use the metal single-piece | unit, salt, and / or complex (these may be named a polyvalent metal ion generically) which has the metal which has several oxidation number as a structural component. Metals having a plurality of oxidation numbers include, for example, iron divalent and trivalent, copper monovalent and divalent, cobalt divalent and trivalent, chromium divalent, trivalent and hexavalent, It has a plurality of oxidation numbers. Preferably, it is a metal simple substance, salt and / or complex as a metal constituent having two kinds of oxidation numbers. Examples of the ligand of the metal complex include water (aquo complex), ammonia (ammonium complex), ethylenediamine, cyan (cyano complex), hydroxyl group (hydroxy complex), halogen (halogeno complex), cyclic ether, pyridine, and the like. Cyclic amine, fullerene, porphyrin, cyclopentadiene (metallocene) and the like are preferable.

As the metal simple substance, salt and / or complex containing the metal having a plurality of oxidation numbers as a constituent, a polyvalent metal compound or simple substance is preferable. Specifically, for example, vanadium oxytrichloride, vanadium trichloride, vanadyl oxalate, vanadyl sulfate, vanadic anhydride, ammonium metavanadate, ammonium sulfate hypovanadas [(NH ₄ ) ₂ SO ₄ · VSO ₄ · 6H ₂ O ], Ammonium sulfate vanadas [(NH ₄ ) V (SO ₄ ) ₂ · 12H ₂ O], copper (II) acetate, copper (II) bromide, copper (II) acetyl acetate, cupric ammonium chloride, copper chloride Ammonium, copper carbonate, copper chloride (II), copper citrate (II), copper formate (II), copper hydroxide (II), copper nitrate, copper naphthenate, copper oleate (II), copper maleate, phosphorus Copper acid, copper sulfate (II), cuprous chloride, copper cyanide (I), copper iodide, copper oxide (I), copper thiocyanate, iron acetyl acetonate, iron ammonium citrate , Ammonium ferrous oxalate, ammonium ammonium sulfate (Mole salt), ferric ammonium sulfate, iron citrate, iron fumarate, iron maleate, ferrous lactate, ferric nitrate, iron pentacarbonyl, phosphorus Water-soluble polyvalent metal salts such as ferric acid and ferric pyrophosphate; polyvalent metal oxides such as vanadium pentoxide, copper (II) oxide, ferrous oxide and ferric oxide; iron sulfide (III ), Iron (II) sulfide, copper sulfide and other polyvalent metal sulfides; copper powder; iron powder; These may be in the form of hydrates. In view of availability and economy, sulfates, halides, and water-soluble complexes are more preferable, and sulfates and water-soluble complexes are more preferable. The metal simple substance, salt and / or complex containing the metal having a plurality of oxidation numbers as a constituent component is preferably made into a circulation line from the above-mentioned polymerization initiator supply port, and the arrangement of the polymerization initiator supply port The number of installations is as described above.

  The above polymerization initiators may be combined. For example, persulfates and sulfites, persulfates and hydrogen peroxide, sulfites and oxygen, polyvalent metal ions and one or more of the above initiators (eg, iron and hydrogen peroxide or persulfate) Salt, iron, persulfate, and sulfite), hydrogen peroxide and thiouric acid, and a reducing organic compound such as L-ascorbic acid or a salt thereof. Among these, a combination of polyvalent metal ions and persulfate is preferable. Specific examples of the polyvalent metal ions include compounds mentioned in the heavy metal-containing compounds described later, for example, water-soluble polyvalent metal salts such as vanadium oxytrichloride, polyvalent metal oxides such as vanadium pentoxide, and sulfides. Examples thereof include polyvalent metal sulfides such as iron (III), complexes containing polyvalent metals such as ammonium iron sulfate (Mole salt), and simple metals such as copper powder. Of these, ammonium iron sulfate (Mole salt) is preferred. That is, as the polymerization initiator, a complex containing a polyvalent metal and a persulfate system are more preferable, and an ammonium iron sulfate (mole salt) and a persulfate system are more preferable. Specifically, a form in which ammonium iron sulfate (Mole salt) and sodium persulfate or ammonium persulfate are combined is preferable.

  In the present invention, when persulfate and bisulfite are used in combination, for example, by using one or more persulfates and bisulfites in combination, a low molecular weight (meta ) An acrylic acid polymer can be obtained, which is preferable. By adding bisulfite to the initiator system in addition to persulfate, the resulting (meth) acrylic acid polymer is prevented from becoming too high in molecular weight, and the molecular weight of the polymer is adjusted. Can do. In addition, when a single metal, a salt and / or a complex containing a metal having a plurality of oxidation numbers as a constituent component is combined, there is an advantage that the reaction rate can be greatly improved. For example, when a mole salt is used in combination, the molecular weight of the resulting (meth) acrylic acid polymer can be easily defined, deoxygenated in bisulfite, and at the same time a water-soluble polymer having a desired molecular weight. Can be obtained. Further, the polymerization rate of the (meth) acrylic acid polymer can be increased.

  In the present invention, when persulfate and bisulfite are used in combination, specifically, as described above, as described above, sodium persulfate (sodium peroxodisulfate), potassium persulfate, ammonium persulfate, etc. Can be mentioned. Sodium persulfate is preferred. Specific examples of the bisulfite include sodium bisulfite, potassium bisulfite, and ammonium bisulfite. Further, sulfite, pyrosulfite, etc. may be used instead of bisulfite.

  In the present invention, when the persulfate and the bisulfite are used in combination, the addition ratio of the persulfate and the bisulfite is preferably 0.5 to 1 part by weight persulfate. It is 5 parts by weight, more preferably 1 to 4 parts by weight, and still more preferably 1.25 to 3 parts by weight. By using 0.5 parts by weight or more of bisulfite with respect to 1 part by weight of persulfate, a sufficient effect of bisulfite can be obtained, and the weight average molecular weight of the (meth) acrylic acid polymer is also sufficient. It can be kept low. On the other hand, by using 5 parts by weight or less of bisulfite with respect to 1 part by weight of persulfate, a sufficient bisulfite addition effect can be obtained, and excessive supply of bisulfite can be suppressed. For this reason, generation | occurrence | production of sulfurous acid gas by an excessive bisulfite being decomposed | disassembled by a polymerization reaction system can be suppressed. Moreover, the performance fall of the (meth) acrylic-acid type polymer obtained and the impurity precipitation at the time of low temperature holding can be prevented effectively, and it does not cause impurity precipitation at the time of low temperature holding, and is preferable. The addition ratio in the case of using a single metal, a salt and / or a complex containing a metal having a plurality of oxidation numbers as a constituent is preferably 20% by weight or less with respect to 100% by weight of persulfate. When it exceeds 20% by weight, the effect of promoting the reaction and the like is maintained, but there is a possibility that the economy is poor. In addition, depending on the metal salt or complex to be added, it may be colored depending on conditions such as pH, and depending on the use of the (meth) acrylic acid polymer, there is a possibility that an undesirable result may be brought about. More preferably, it is 0.2 weight% or less, More preferably, it is 0.02 weight% or less.

  In the present invention, when persulfate and bisulfite are used in combination, the total amount of persulfate and bisulfite is added to 1 mol of the monomer component. Preferably it is 2-20g, More preferably, it is 4-15g, More preferably, it is 6-12g, Most preferably, it is 6-9g. In the present invention, persulfate and bisulfite may be added in such a low addition amount range, and the generation of impurities can be reduced. Furthermore, the performance degradation of the (meth) acrylic acid-type polymer obtained and the impurity precipitation at the time of low-temperature holding | maintenance can be prevented. When the addition amount of the above-mentioned polymerization initiator persulfate and bisulfite is in the range of 2 to 20 g, it has a good molecular weight (without adverse effects such as a decrease in purity of the obtained (meth) acrylic acid polymer). A (meth) acrylic acid polymer can be obtained efficiently. The addition amount in the case of using a single metal, a salt and / or a complex containing a metal having a plurality of oxidation numbers as a constituent component is 1.5% by weight or less with respect to 100% by weight of the monomer component. It is preferable. When it exceeds 1.5% by weight, the effect of promoting the reaction and the like is maintained, but there is a risk of being inferior in economic efficiency. In addition, depending on the metal salt or complex to be added, it may be colored depending on conditions such as pH, and depending on the use of the (meth) acrylic acid polymer, there is a possibility that an undesirable result may be brought about. More preferably, it is 0.015 weight% or less, More preferably, it is 0.0015 weight% or less.

  The persulfate may be dissolved in the aqueous solvent and added in the form of a persulfate solution (preferably an aqueous solution). The concentration when used as the persulfate solution (preferably an aqueous solution) is preferably 1 to 35% by weight, more preferably 5 to 35% by weight, and still more preferably 10 to 30% by weight. Here, when the concentration of the persulfate solution is less than 1% by weight, the concentration of the product is lowered, and transportation and storage become complicated. On the other hand, when the concentration of the persulfate solution exceeds 35% by weight, the persulfate may be precipitated.

  When producing a (meth) acrylic acid polymer by batch polymerization, the end time of addition of persulfate (solution) during polymerization is greater than the end time of addition of (meth) acrylic acid monomer (solution). It is preferable to delay. Specifically, the delay is preferably 1 to 30 minutes, more preferably 1 to 20 minutes, and still more preferably 1 to 15 minutes. Thereby, the amount of the monomer component remaining after the completion of the polymerization can be reduced, and impurities caused by the remaining monomer can be significantly reduced.

  When producing a (meth) acrylic acid polymer by batch polymerization, the persulfate (solution) addition completion time is less than 1 minute later than the (meth) acrylic acid monomer (solution) addition completion time. If this is not possible, the monomer component may remain after completion of the polymerization. In such a case, the end of the addition of the persulfate (solution) and the end of the addition of the (meth) acrylic monomer (solution) are the same, or the end of the addition of the persulfate (solution). Is earlier than the end of the addition of the (meth) acrylic acid monomer (solution). In such a case, it is difficult to effectively and effectively suppress the formation of impurities. On the other hand, if the addition end time of the persulfate (solution) is more than 30 minutes later than the addition end time of the (meth) acrylic acid monomer (solution), the persulfate or the decomposition thereof after completion of the polymerization There is a risk that objects remain and impurities are formed.

  In the present invention, when a persulfate and a bisulfite are used in combination, the bisulfite is dissolved in the aqueous solvent when the (meth) acrylic acid polymer is produced by batch polymerization. It may be added in the form of a solution (preferably an aqueous solution). The concentration when used as the bisulfite solution (preferably an aqueous solution) is preferably 10 to 40% by weight, more preferably 20 to 40% by weight, and still more preferably 30 to 40% by weight. By setting the concentration of the bisulfite solution within the above range, a product having a sufficient concentration can be obtained without fear of precipitation of bisulfite, which is preferable for transportation and storage.

  Further, in bisulfite, the molecular weight at the initial stage of polymerization greatly affects the final molecular weight. For this reason, in the present invention, when a persulfate and a bisulfite are used in combination, in order to reduce the initial molecular weight, when a (meth) acrylic acid polymer is produced by batch polymerization, it is preferably 60 from the start of polymerization. Within 5 minutes, more preferably within 30 minutes, and even more preferably within 10 minutes by adding bisulfite or a solution thereof in an amount of 5 to 20% by weight, especially when polymerization is started from room temperature. It is.

  In the present invention, when persulfate and bisulfite are used in combination, the addition time of the bisulfite or the solution thereof among the components added during the polymerization is determined by batch polymerization. When producing a coalescence, it is preferably 1 to 30 minutes, more preferably 1 to 20 minutes, and even more preferably 1 to 15 minutes before the end of the addition of the (meth) acrylic acid monomer (solution). Thus, the amount of bisulfite after the completion of polymerization can be reduced, and generation of sulfurous acid gas and formation of impurities by the bisulfite can be effectively and effectively suppressed. For this reason, after the polymerization is completed, impurities formed by dissolving the sulfurous acid gas in the gas phase in the liquid phase can be significantly reduced. When bisulfite remains after the completion of the polymerization, impurities are generated, leading to deterioration in the performance of the polymer and precipitation of impurities when kept at a low temperature. Therefore, it is more desirable that the initiator containing bisulfite is consumed and does not remain at the end of the polymerization.

  Here, in the present invention, when the persulfate and the bisulfite are used in combination, when the (meth) acrylic acid polymer is produced by batch polymerization, the addition end time of the bisulfite (solution) is set to (meta ) When the addition time of the acrylic acid monomer (solution) can be shortened by less than 1 minute, the bisulfite may remain after completion of the polymerization. In such cases, the end of the addition of bisulfite or its solution and the end of the addition of the (meth) acrylic acid monomer (solution), or the end of the addition of bisulfite (solution) Includes a case that is later than the end of the addition of the (meth) acrylic acid monomer (solution). In such a case, it becomes difficult to effectively and effectively suppress the generation of sulfurous acid gas and the formation of impurities, which may adversely affect the thermal stability of the polymer from which the remaining initiator is obtained. On the other hand, when the addition end time of bisulfite or its solution exceeds 30 minutes earlier than the addition end time of the (meth) acrylic acid monomer (solution), the bisulfite is consumed by the end of the polymerization. It has been done. For this reason, there exists a possibility of causing the increase in molecular weight. In addition, the addition rate of bisulfite during polymerization is faster than the addition rate of (meth) acrylic acid monomer (solution) and is added in a short time. A large amount of sulfurous acid gas may be generated.

  Moreover, in this invention, it is also preferable to use together 1 type, or 2 or more types of persulfate and hydrogen peroxide as a polymerization initiator. In some cases, a chain transfer agent or a polyvalent metal ion may be used (wherein the polyvalent metal ion serves as a decomposition accelerator for the polymerization initiator), and both of these may be used simultaneously.

  In the present invention, when persulfate and hydrogen peroxide are used in combination, the amount of hydrogen peroxide added is preferably 2.0 to 10.0 g with respect to 1 mol of the monomer component, and 3.0 More preferably, it is -8.0g. When the amount of hydrogen peroxide added is 2.0 g or more, a (meth) acrylic acid polymer having a sufficiently low polymerization average molecular weight can be obtained. Further, when the addition amount is 10.0 g or less, there is no adverse effect due to the remaining hydrogen peroxide, and a sufficiently effective hydrogen peroxide effect can be obtained. The amount of the persulfate added is preferably 1.0 to 5.0 g and more preferably 2.0 to 4.0 g with respect to 1 mol of the monomer. A (meth) acrylic acid polymer having a sufficiently low molecular weight can be obtained when the amount of persulfate added is 1.0 g or more, and (meth) acrylic acid obtained when the amount added is 5.0 g or less. A sufficiently effective persulfate effect can be obtained without causing a decrease in the purity of the polymer.

  In the present invention, when persulfate and hydrogen peroxide are used in combination, the addition ratio of hydrogen peroxide and persulfate is as follows. It is preferable that it is 0.1-5.0, and it is more preferable that it is 0.5-3.0. When the weight ratio of persulfate is 0.1 or more, the weight average molecular weight of the resulting (meth) acrylic acid polymer can be kept sufficiently low. Obtainable.

  In the present invention, other initiators may be appropriately used as necessary as long as the effects of the present invention are not adversely affected. In the present invention, as the initiator system, the above-mentioned persulfate alone (including the case of using a chain transfer agent), or a simple metal, a salt and / or a persulfate and a metal having a plurality of oxidation numbers. Alternatively, a combination of complexes (polyvalent metal ions) is preferably used, but is not particularly limited. That is, as long as the effects of the present invention are exhibited, the above-described initiator may be used, other initiators may be used, and other initiators may be used in addition to the above-described initiators. Also good. Examples of other initiators include 2,2′-azobis (2-amidinopropane) hydrochloride, 4,4′-azobis-4-cyanoparellinic acid, azobisisobutyronitrile, 2,2′-azobis ( Azo compounds such as 4-methoxy-2,4-dimethylvaleronitrile); benzoyl peroxide, lauroyl peroxide, peracetic acid, di-t-butyl peroxide, t-butyl hydroperoxide, cumene hydroperoxide, etc. Organic peroxide; hydrogen peroxide; and the like.

  The other initiator may be added in the form of an aqueous solution after being dissolved in the aqueous solvent. The concentration when used as the aqueous solution may be in a range that does not impair the effects of the present invention, and is usually appropriately determined based on the same level as the concentration of the above-described persulfate or bisulfite solution.

C-4. Phosphorus-containing compound In the present invention, a phosphorus-containing compound is essential. As the phosphorus-containing compound, any appropriate phosphorus-containing compound can be adopted as long as it is a compound containing a phosphorus atom and can function as a chain transfer agent. Particularly preferred phosphorus-containing compounds in the present invention are hypophosphorous acid and hypophosphite (for example, sodium hypophosphite). In the present invention, it is important to supply 3 to 7 g of the phosphorus-containing compound with respect to 1 mol of the (meth) acrylic acid monomer. By supplying a predetermined amount of the phosphorus-containing compound as described above, the effects of the present invention are sufficiently exhibited. In particular, it is possible to produce a (meth) acrylic acid polymer having a very excellent dispersibility of the calcium carbonate slurry and a narrow molecular weight distribution. The supply amount of the phosphorus-containing compound with respect to 1 mol of the (meth) acrylic acid monomer is preferably 3.1 to 6.5 g, more preferably 3.2 to 6.3 g.

C-5. Chain Transfer Agent In the present invention, a chain transfer agent other than the phosphorus-containing compound may be used. Examples of chain transfer agents other than phosphorus-containing compounds include, for example, sulfurous acid (salt), hydrogen sulfite (salt), pyrosulfurous acid (salt), thioglycolic acid, octyl thioglycolate, thiopropionic acid, octyl thiopropionate, n- Dodecyl mercaptan, t-dodecyl mercaptan, ethylene glycol dithioglycolate, ethylene glycol dithiopropionate, 1,4-butanediol thioglycolate, trimethylolpropane trithioglycolate, trimethylolpropane trithiopropionate, pentaerythritol Inclusion of mercapto groups such as tetrakisthioglycolate, pentaerythritol tetrakisthiopropionate, dipentaerythritol hexakisthioglycolate, dipentaerythritol hexakisthiopropionate Things, butanethiol, octanethiol, decanethiol, hexadecane thiol, octadecane thiol, cyclohexyl mercaptan, thiophenol, mercaptoethanol, thioglycerol, thiomalic acid, 2-mercapto-ethanesulfonic acid, isopropanol, glycerin.

C-6. Alkaline Agent An alkali agent (also referred to as a pH adjuster or a neutralizer) may be used to adjust the pH of the reaction solution during polymerization or to neutralize the monomer component. Examples of the alkali agent include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide; alkaline earth metal hydroxides such as calcium hydroxide and magnesium hydroxide; ammonia; monoethanolamine and triethanolamine. And the like, and the like. These may be used alone or in combination of two or more. Among these, alkali metal hydroxides such as sodium hydroxide and potassium hydroxide and ammonia are preferable, and sodium hydroxide and ammonia are more preferable.

  The degree of neutralization during the polymerization is preferably 0 to 25 mol%, but preferably 0 to 15 mol% when the monomer component used for the polymerization is only a (meth) acrylic acid monomer. More preferably, it is in the range of 0 to 10 mol%. When the monomer used for polymerization contains the monomer (I) or monomer (II), a part or all of the monomer (I) or monomer (II) is initially It is possible to charge. The degree of neutralization during the polymerization at this time is preferably in the range of 0 to 25 mol%, more preferably 0 to 10 mol%. If the degree of neutralization during polymerization is within this range, good copolymerization is possible. Moreover, the viscosity of the aqueous solution of the polymerization reaction system does not increase, and a low molecular weight polymer can be produced satisfactorily. In addition, since the polymerization reaction can proceed under higher concentration conditions than in the prior art, production efficiency can be significantly increased. When an initiator system that generates volatile gas, for example, when using sulfite, if the degree of neutralization during polymerization is 1 mol% or more, the amount of sulfurous acid gas generated can be satisfactorily suppressed, and the resulting polymer This is preferable because the molecular weight can be kept sufficiently low. Further, if the degree of neutralization during polymerization is 25 mol% or less, sufficient bisulfite chain transfer efficiency can be obtained, so that the molecular weight of the resulting polymer can be kept sufficiently low, The increase in the viscosity of the aqueous solution of the polymerization reaction system as the polymerization proceeds can be suppressed, and a low molecular weight polymer can be obtained without unnecessarily increasing the molecular weight of the resulting polymer, which is preferable. Furthermore, since the effect by the said neutralization degree reduction can fully be exhibited and an impurity can be reduced, it is preferable. On the other hand, in the case of using an initiator system that does not generate volatile gas, for example, persulfate, hypophosphite, and polyvalent metal ions, there is no need to suppress volatile components by neutralization. The reaction can be carried out even when the degree is 0 mol%.

  Any appropriate method can be adopted as the neutralization method. As the neutralizing agent, for example, an alkaline monomer component such as sodium (meth) acrylate may be used, or an alkali metal hydroxide such as sodium hydroxide may be used. You may use together. The form of addition of the neutralizing agent at the time of neutralization may be a solid or an aqueous solution dissolved in an appropriate solvent, preferably water. When using an aqueous solution, the concentration of the aqueous solution is preferably 10 to 60% by weight, more preferably 20 to 55% by weight, and still more preferably 30 to 50% by weight. If the concentration of the aqueous solution is 10% by weight or more, a product having a good concentration can be obtained, which is preferable for transportation and storage. If the density | concentration of aqueous solution is 60 weight% or less, there is no possibility of precipitation or a viscosity raise, and liquid feeding and liquid-liquid mixing are easy, and it is preferable.

C-7. Oxidizing agent As oxidizing agent, oxygen, ozone, hydrogen peroxide, persulfate, perchlorate, permanganate, dichromate, bromate, nitric acid (salt), hypochlorite, etc. are suitable It is. The oxidizing agent can be selected depending on the type of initiator, the corrosiveness to the apparatus, and the components remaining in the resulting water-soluble polymer. Among them, oxygen, ozone, hydrogen peroxide, and persulfate are preferable.

C-8. Other Additives As other additives that can be used in the polymerization reaction system, an appropriate amount of any appropriate additive can be added as long as the effects of the present invention are not affected. For example, it is preferable to use a heavy metal-containing compound, an organic peroxide, hydrogen peroxide (H ₂ O ₂ ) and a metal salt. By using such an additive, the reaction can be accelerated, and it is preferable to add them from the viewpoint of production efficiency. As said heavy metal containing compound, the thing as described in the metal simple substance, salt, and / or complex which uses the metal which has several oxidation number mentioned above as a structural component can be used as an additive, for example.

  Since the heavy metal ion concentration of the (meth) acrylic acid polymer in the present invention is preferably 0.05 to 10 ppm, it is preferable to add an appropriate amount of the heavy metal-containing compound as necessary. Furthermore, in the present invention, when a SUS (stainless steel) container, a stirrer, or the like is used, an appropriate amount of heavy metal ions specified above, particularly iron ions, is introduced into the reaction solution from SUS, which is the material of the container. Elution (supply) in a very small amount is advantageous in terms of cost effectiveness. In the present invention, when such a reaction device such as a SUS reaction vessel or a stirring blade is used, the same effect as that in the case of adding the heavy metal-containing compound can be obtained. Although there is no problem even with an existing reaction vessel made of steel or copper alloy, there is a possibility that a lot of heavy metal ions are eluted. In such a case, since coloring occurs due to heavy metal, an operation for removing heavy metal ions is required, which is uneconomical.

≪D. Application >>
D-1. Dispersant The dispersant of the present invention contains the (meth) acrylic acid polymer of the present invention. The dispersant of the present invention may be an aqueous dispersant, and for example, a pigment dispersant, a cement dispersant, a calcium carbonate dispersant, a kaolin dispersant, and the like are suitable. Since the dispersant of the present invention contains the (meth) acrylic acid polymer of the present invention, it can exhibit extremely excellent dispersibility. Since the dispersant of the present invention contains the (meth) acrylic acid polymer of the present invention, it is extremely high-quality, high-performance and stable without degradation of performance or precipitation of impurities when kept at low temperatures even after long-term storage. Dispersant with excellent properties.

  As other composition components and blending ratios of the dispersant of the present invention other than the (meth) acrylic acid polymer of the present invention, various components that can be used in ordinary dispersants and blending ratios thereof are used. It can set suitably in the range which does not impair the effect of invention.

  The dispersant of the present invention can be particularly preferably used as an inorganic pigment dispersant. If necessary, the inorganic pigment dispersant may use condensed phosphoric acid and a salt thereof, phosphonic acid and a salt thereof, and polyvinyl alcohol as another compounding agent.

  The content of the (meth) acrylic acid polymer of the present invention in the inorganic pigment dispersant is preferably 5 to 100% by weight with respect to the whole inorganic pigment dispersant. Further, any appropriate water-soluble polymer may be included as long as it does not affect the performance and effect.

  The inorganic pigment dispersant can exhibit good performance as a dispersant for heavy or light calcium carbonate or clay inorganic pigment used in paper coating. For example, by adding a small amount of an inorganic pigment dispersant to an inorganic pigment and dispersing it in water, high concentration calcium carbonate having low viscosity and high fluidity and good aging stability of their performance. High concentration inorganic pigment slurries such as slurries can be produced.

  When the inorganic pigment dispersant is used as a dispersant for an inorganic pigment, the amount of the inorganic pigment dispersant used is preferably 0.05 to 2.0 parts by weight with respect to 100 parts by weight of the inorganic pigment. When the amount of the inorganic pigment dispersant used is less than 0.05 parts, there is a possibility that a sufficient dispersing effect cannot be obtained. If the amount of the inorganic pigment dispersant used exceeds 2.0 parts by weight, the effect corresponding to the amount added may not be obtained, which may be economically disadvantageous.

D-2. Detergent Composition The detergent composition of the present invention contains the (meth) acrylic acid polymer of the present invention. In the detergent composition of the present invention, the amount of the (meth) acrylic acid polymer of the present invention is preferably 1 to 20% by weight based on the whole detergent composition. If the blending amount of the (meth) acrylic acid polymer is less than 1% by weight based on the entire detergent composition, the effect of addition may not be exhibited. If the blending amount of the (meth) acrylic acid polymer exceeds 20% by weight with respect to the whole detergent composition, the added effect does not lead to an improvement in cleaning power, which may be economically disadvantageous.

  The detergent composition of the present invention includes any appropriate surfactant, enzyme, alkali builder, chelate builder, anti-redeposition agent, soil release agent, color transfer inhibitor, softener, fluorescent agent, if necessary. You may mix | blend the component normally used for detergent compositions, such as a bleaching agent, a bleaching assistant, a fragrance | flavor, a foaming agent, an antifoamer, an antibacterial agent, a corrosion inhibitor, and a coloring agent. Moreover, you may mix | blend a zeolite.

  As the surfactant, at least one selected from the group consisting of an anionic surfactant, a nonionic surfactant, an amphoteric surfactant and a cationic surfactant can be used.

  Any appropriate anionic surfactant can be adopted as the anionic surfactant. For example, alkylbenzene sulfonate, alkyl or alkenyl ether sulfate, alkyl or alkenyl sulfate, α-olefin sulfonate, α-sulfo fatty acid or ester salt, alkane sulfonate, saturated or unsaturated fatty acid salt, alkyl or alkenyl Examples include ether carboxylates, amino acid type surfactants, N-acyl amino acid type surfactants, alkyl or alkenyl phosphate esters or salts thereof.

  Any appropriate nonionic surfactant can be adopted as the nonionic surfactant. For example, polyoxyalkylene alkyl or alkenyl ether, polyoxyethylene alkyl phenyl ether, higher fatty acid alkanolamide or its alkylene oxide adduct, sucrose fatty acid ester, alkyl glycoxide, fatty acid glycerin monoester, alkyl amine oxide and the like can be mentioned.

  Any appropriate amphoteric surfactant can be adopted as the amphoteric surfactant. For example, carboxy type or sulfobetaine type amphoteric surfactants and the like can be mentioned.

  Any appropriate cationic surfactant can be adopted as the cationic surfactant. Examples thereof include quaternary ammonium salts.

  Any appropriate enzyme can be adopted as the enzyme that can be blended in the detergent composition of the present invention.

  Examples of the enzyme include protease, lipase, cellulase and the like. In particular, protease, alkaline lipase and alkaline cellulase having high activity in the alkaline washing solution are preferable.

  Any appropriate alkali builder can be adopted as the alkali builder. For example, silicate, carbonate, sulfate and the like can be mentioned.

  Any appropriate chelate builder can be adopted as the chelate builder. For example, diglycolic acid (salt), oxycarboxylic acid (salt), EDTA (ethylenediaminetetraacetic acid), DTPA (diethylenetriaminehexaacetic acid), citric acid (salt), 3-hydroxy-2,2'-iminodisuccinic acid (salt) , L-aspartate diacetate (salt), methylglycine diacetate (salt), L-glutamine diacetate (salt), and the like.

D-3. Water Treatment Agent The water treatment agent of the present invention contains the (meth) acrylic acid polymer of the present invention. In the water treatment agent of the present invention, a polymerized phosphate, phosphonate, anticorrosive, slime control agent, and chelating agent may be used as other compounding agents as necessary.

  The water treatment agent of the present invention is useful for scale prevention in a cooling water circulation system, a boiler water circulation system, a seawater desalination apparatus, a pulp digester, a black liquor concentration tank, and the like. Further, any appropriate water-soluble polymer may be included as long as it does not affect the performance and effects.

D-4. Scale inhibitor The scale inhibitor of the present invention comprises the (meth) acrylic acid polymer of the present invention. The scale inhibitor of the present invention is excellent in the prevention and removal of various scales such as calcium carbonate, calcium phosphate, magnesium silicate, zinc hydroxide, zinc phosphate, barium sulfate, calcium sulfate, magnesium hydroxide, silica, and iron. To demonstrate.

  The scale inhibitor of the present invention may be composed of only the (meth) acrylic acid polymer of the present invention, and may contain any appropriate other scale inhibitor as necessary. Other scale inhibitors include, for example, acrylic acid polymers, maleic acid polymers, acrylic acid, and monoethylenic acids such as 2-hydroxy-3-allyloxypropane sulfonic acid and acrylamide-2-methylpropane sulfonic acid. Examples thereof include a copolymer with an unsaturated sulfonic acid compound. Moreover, content of the (meth) acrylic acid-type polymer of this invention in the scale inhibitor of this invention becomes like this. Preferably it is 10-100 weight%, More preferably, it is 20-100 weight%.

  The scale inhibitor of the present invention may be used together with a drug generally used in water treatment. Examples of the agent include metal corrosion inhibitors such as phosphoric acid compounds such as polymerized phosphates, phosphonates, and phosphonocarboxylic acids, and metal salts such as zinc; chlorine, hypochlorite, hydrazine, etc. Such as antibacterial agent, anti-slime agent, sludge dispersant, antifoaming agent, oxygen scavenger, and the like. These drugs may be used alone or in combination of two or more. What is necessary is just to set the usage-amount of the said chemical | medical agent suitably. By using the scale inhibitor of the present invention together with the above agent, a very effective water treatment can be performed.

  Since the scale preventive agent of the present invention is excellent in scale preventive ability in all aqueous systems, the addition amount is usually preferably about 0.1 to 100 ppm. The scale inhibitor of the present invention may be added as it is to a water system such as a cooling water system, a boiler water system, a seawater desalination device, an oil feed, a dust collection water system, a pulp dissolving kettle, a black liquor concentration kettle, You may mix and add.

D-4. Other uses
The (meth) acrylic acid polymer of the present invention is very excellent in dispersibility of calcium carbonate slurry and has a narrow molecular weight distribution, so that it can also be used for any other appropriate application. For example, it can be used for fiber treatment agents, metal ion encapsulants, thickeners, various binders, and the like. Taking the case of using as a fiber treating agent as an example, the fiber treating agent includes at least one selected from the group consisting of a dyeing agent, a peroxide and a surfactant, and the (meth) acrylic acid polymer of the present invention. .

  The content of the (meth) acrylic acid polymer of the present invention in the fiber treatment agent is preferably 1 to 100% by weight, more preferably 5 to 100% by weight, based on the entire fiber treatment agent. Further, any appropriate water-soluble polymer may be included as long as the performance and effects are not affected.

  The fiber treatment agent can be used in the steps of refining, dyeing, bleaching and soaping in fiber treatment. Examples of the dyeing agent, peroxide, and surfactant include those usually used for fiber treatment agents.

  The blending ratio of the (meth) acrylic acid polymer of the present invention to at least one selected from the group consisting of a dye, a peroxide, and a surfactant is, for example, whiteness of fibers, uneven color, and dyeing warp In order to improve the degree, the fiber treatment agent is selected from the group consisting of a dye, a peroxide and a surfactant with respect to 1 part by weight of the (meth) acrylic acid polymer of the present invention in terms of a pure component. It is preferable to use at least one at a ratio of 0.1 to 100 parts by weight.

  Arbitrary appropriate fiber can be employ | adopted as a fiber which can use the said fiber processing agent. Examples thereof include cellulosic fibers such as cotton and hemp, chemical fibers such as nylon and polyester, animal fibers such as wool and silk, semi-synthetic fibers such as human silk, and woven fabrics and blended products thereof.

  When the fiber treatment agent is applied to the refining process, it is preferable to blend the (meth) acrylic acid polymer of the present invention with an alkali agent and a surfactant. When applied to the bleaching step, it is preferable to blend the (meth) acrylic acid polymer of the present invention, a peroxide, and a silicic acid agent such as sodium silicate as a decomposition inhibitor for the alkaline bleaching agent.

EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these Examples. Unless otherwise specified, parts and% in the examples are based on weight.
<Measurement of ³¹ P-NMR>
The polymer to be measured was dried under reduced pressure at room temperature, and the resulting solid content was dissolved in heavy water (Aldrich) so as to be 10% by weight, and Varian's UnityPlus-400 (400 MHz, pulse sequence: s2pu1, measurement interval). 100.00 seconds, pulse: 45.0 degrees, capture time: 0.800 seconds, integration number: 128 times).

[Example 1]
A 2 L glass separable flask was provided with a pump for extracting the reaction liquid, and a circulation line capable of adjusting the opening degree, coming out of the flask and circulating outside the flask and returning to the flask. The circulation line was provided with a raw material supply port, a cooler and a static mixer. In addition, a discharge line was branched off from the circulation line. In addition, a stirring blade was installed in the flask. In this way, a loop line type reactor (polymer production apparatus) was produced.
This separable flask was charged with 720 g of water in advance and heated to the temperature shown in Table 1. Under such conditions, the reaction liquid extraction pump is started, and the temperature of the cooling water and the amount of cooling water are adjusted so that the temperature in the flask is maintained, and an 80 wt% aqueous acrylic acid solution (80% AA) is supplied from the raw material supply port. Table 1 shows an aqueous solution of 45 wt% sodium phosphinate (sodium hypophosphite) (45% SHP), an aqueous solution of 15 wt% sodium persulfate (sodium peroxodisulfate) (15% NaPS), and a 5 ppm molle salt aqueous solution. Each was added in the prescription. The molecular weight was adjusted by appropriately adjusting the reaction conditions. The reaction time was 6 hours. Further, the circulation ratio (= circulation amount / external liquid removal amount) was adjusted to be 10. After the reaction, the raw material supply and circulation were stopped, and the reaction solution remaining in the flask was cooled and taken out, and neutralized until 48 mass% sodium hydroxide was added until pH = 7.
The weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn) of the obtained polymer (1) were measured by GPC. The results are shown in Table 3.

[Example 2]
Except having performed by the prescription shown in Table 1, it carried out like Example 1 and the polymer (2) was obtained.
The weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn) of the obtained polymer (2) were measured by GPC. The results are shown in Table 3.
Furthermore, ³¹ P-NMR measurement of the obtained polymer (2) was performed. From the integrated intensity in the obtained NMR chart, the integrated intensity ratio of phosphorus atoms arranged at the end of the main chain and the integrated intensity ratio of phosphorus atoms inserted into the main chain when the integrated intensity of the remaining SHP is set to 1 are calculated. The ratio (molar ratio) of the main chain internal insertion phosphorus atomic weight to the arranged phosphorus atomic weight was calculated. The results are shown in Table 4.

Example 3
Except having performed by the prescription shown in Table 1, it carried out similarly to Example 1 and obtained the polymer (3).
The weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn) of the obtained polymer (3) were measured by GPC. The results are shown in Table 3.

Example 4
Except having performed by the prescription shown in Table 1, it carried out like Example 1 and the polymer (4) was obtained.
The weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn) of the obtained polymer (4) were measured by GPC. The results are shown in Table 3.

Example 5
Except having performed by the prescription shown in Table 1, it carried out like Example 1 and the polymer (5) was obtained.
The weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn) of the obtained polymer (5) were measured by GPC. The results are shown in Table 3.
Furthermore, ³¹ P-NMR measurement of the obtained polymer (5) was performed. From the integrated intensity in the obtained NMR chart, the integrated intensity ratio of phosphorus atoms arranged at the end of the main chain and the integrated intensity ratio of phosphorus atoms inserted into the main chain when the integrated intensity of the remaining SHP is set to 1 are calculated. The ratio (molar ratio) of the main chain internal insertion phosphorus atomic weight to the arranged phosphorus atomic weight was calculated. The results are shown in Table 4.

Example 6
Except having performed by the prescription shown in Table 1, it carried out like Example 1 and the polymer (6) was obtained.
The weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn) of the obtained polymer (6) were measured by GPC. The results are shown in Table 3.

[Comparative Example 1: Batch polymerization]
Water and Mole salt were added to a 2 L glass separable flask as shown in Table 2 and heated to the temperature shown in Table 2. While stirring, while maintaining the temperature in the flask at the temperature, 80% by weight acrylic acid aqueous solution (80% AA), 45% by weight sodium phosphinate (sodium hypophosphite) aqueous solution ( 45% SHP) and 15% by weight sodium persulfate (sodium peroxodisulfate) aqueous solution (15% NaPS) were added in the formulations shown in Table 2, respectively. The molecular weight was adjusted by appropriately adjusting the reaction conditions.
The temperature was kept for 30 minutes after the supply of the raw materials was completed, and then cooled, and 48 wt% sodium hydroxide was added to neutralize until pH = 7.
The weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn) of the obtained polymer (C1) were measured by GPC. The results are shown in Table 3.

[Comparative Example 2: Batch polymerization]
Except having performed by the prescription shown in Table 2, it carried out similarly to the comparative example 1, and obtained the polymer (C2).
The weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn) of the obtained polymer (C2) were measured by GPC. The results are shown in Table 3.

[Comparative Example 3: Batch polymerization]
Except having performed by the prescription shown in Table 2, it carried out similarly to the comparative example 1, and obtained the polymer (C3).
The weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn) of the obtained polymer (C3) were measured by GPC. The results are shown in Table 3.

[Comparative Example 4: Batch polymerization]
Except having performed by the prescription shown in Table 2, it carried out similarly to the comparative example 1, and obtained the polymer (C4).
The weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn) of the obtained polymer (C4) were measured by GPC. The results are shown in Table 3.

[Comparative Example 5: Batch polymerization]
Except having performed by the prescription shown in Table 2, it carried out similarly to the comparative example 1, and obtained the polymer (C5).
The weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn) of the obtained polymer (C5) were measured by GPC. The results are shown in Table 3.
Furthermore, ³¹ P-NMR measurement of the obtained polymer (C5) was performed. From the integrated intensity in the obtained NMR chart, the integrated intensity ratio of phosphorus atoms arranged at the end of the main chain and the integrated intensity ratio of phosphorus atoms inserted into the main chain when the integrated intensity of the remaining SHP is set to 1 are calculated. The ratio (molar ratio) of the main chain internal insertion phosphorus atomic weight to the arranged phosphorus atomic weight was calculated. The results are shown in Table 4.

[Comparative Example 6: Batch polymerization]
Except having performed by the prescription shown in Table 2, it carried out similarly to the comparative example 1, and obtained the polymer (C6).
The weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn) of the obtained polymer (C6) were measured by GPC. The results are shown in Table 3.
Furthermore, ³¹ P-NMR measurement of the obtained polymer (C6) was performed. From the integrated intensity in the obtained NMR chart, the integrated intensity ratio of phosphorus atoms arranged at the end of the main chain and the integrated intensity ratio of phosphorus atoms inserted into the main chain when the integrated intensity of the remaining SHP is set to 1 are calculated. The ratio (molar ratio) of the main chain internal insertion phosphorus atomic weight to the arranged phosphorus atomic weight was calculated. The results are shown in Table 4.

[Comparative Example 7: Batch polymerization]
To a 2 L glass separable flask, water, 45 wt% sodium phosphinate (sodium hypophosphite) aqueous solution (45% SHP), and Mole salt were added as shown in Table 2, and heated to the temperature shown in Table 2. . While stirring, while maintaining the temperature in the flask at the temperature, 80% by weight acrylic acid aqueous solution (80% AA), 45% by weight sodium phosphinate (sodium hypophosphite) aqueous solution ( 45% SHP) and 15% by weight sodium persulfate (sodium peroxodisulfate) aqueous solution (15% NaPS) were added in the formulations shown in Table 2, respectively. The molecular weight was adjusted by appropriately adjusting the reaction conditions.
The temperature was kept for 30 minutes after the supply of the raw materials was completed, and then cooled, and 48 wt% sodium hydroxide was added to neutralize until pH = 7.
The weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn) of the obtained polymer (C7) were measured by GPC. The results are shown in Table 3.

[Example 7: Evaluation of dispersibility of calcium carbonate slurry]
200 g of “heavy calcium carbonate” manufactured by Maruo Calcium Co., Ltd. was placed in a bead mill (pulverizer) and stirred at a low speed (about 300 rpm), and the aqueous solution of the polymer (2) obtained in Example 2 (in terms of solid content) (10 wt%) 9.50 g and 43.50 g of water were added. While further stirring, 500 g of alumina beads having a particle diameter of 2 mm were slowly added, and then the timing was started, and the rotation speed was maintained at about 500 rpm for the initial 5 minutes, about 1000 rpm for the next 5 minutes, and then about 1400 rpm. While being dispersed.
In 40 minutes from the start of pulverization, 4.75 g of the aqueous solution of the above polymer (2) was added, and 2.375 g was added in 70 minutes and 90 minutes, respectively. While measuring with a distribution meter (LA-910, manufactured by Horiba, Ltd.), pulverization was continued until the amount of 2 μm or less reached 93% or more.
The obtained slurry is put on a 1 mm sieve, and the slurry and beads are sieved, and then the slurry is a container (having a height and an inner diameter that can be measured later with a Brookfield viscometer, and about 50 mL in volume. ).
The collected sample was adjusted to 25 ° C. and stored, and the slurry was homogenized by shaking for 1 minute at 120 times / minute or more before measurement. Then, using a Brookfield viscometer (manufactured by Tokimec, product number: BM), the spindle No. The sample was rotated for 1 minute under the condition of 3, 60 rpm, and the value after 1 minute was read.
The measurement described above required measurement after 1 hour, 3 hours, 1 day, and 7 days after collecting the slurry, and data after 2 to 6 days were arbitrarily measured to confirm the change in viscosity.
The measurement results are shown in Table 5.

[Example 8: Evaluation of dispersibility of calcium carbonate slurry]
The same procedure as in Example 7 was performed except that the polymer (5) obtained in Example 5 was used in place of the polymer (2) obtained in Example 2.
The measurement results are shown in Table 5.

[Comparative Example 8: Evaluation of dispersibility of calcium carbonate slurry]
The same procedure as in Example 7 was performed except that the polymer (C5) obtained in Comparative Example 5 was used in place of the polymer (2) obtained in Example 2.
The measurement results are shown in Table 5.

[Comparative Example 9: Evaluation of dispersibility of calcium carbonate slurry]
The same procedure as in Example 7 was performed except that the polymer (C7) obtained in Comparative Example 7 was used in place of the polymer (2) obtained in Example 2.
The measurement results are shown in Table 5.

  The four polymers evaluated for the dispersibility of the calcium carbonate slurry each have almost the same weight average molecular weight (Mw), and are components derived from a polymerization initiator and a chain transfer agent contained in the solid content of the polymer. The amount is almost unchanged. The increase in slurry viscosity for the polymer (2) was about 200 mPa · s, and the increase in slurry viscosity for the polymer (5) was about 250 mPa · s. In contrast, the polymer (C5) had a high initial viscosity and an increase in slurry viscosity of about 500 mPa · s. Further, regarding the polymer (C7), although the initial viscosity was not high, the increase in slurry viscosity was about 700 mPa · s.

  It is presumed that in order for the dispersibility of the calcium carbonate slurry to be excellent, adsorption to the calcium carbonate surface and force to repel particles (electrostatic repulsion and steric hindrance) are necessary. Since the (meth) acrylic acid polymer of the present invention has a large amount of phosphorus atoms inserted into the main chain, adsorption of the inserted portion onto the surface of calcium carbonate occurs and many phosphorus atoms are inserted into the main chain. It is considered that the steric hindrance increases due to this, and it is considered that the dispersibility of the calcium carbonate slurry is excellent.

  Since the polymer (2) and the polymer (5) have a large amount of phosphorus atoms fitted inside the main chain (Table 4), they have a structure capable of efficiently dispersing the calcium carbonate slurry. Furthermore, since the polymer (2) and the polymer (5) have a narrow molecular weight distribution (Mw / Mn) (Table 3), components having a molecular weight preferable as a dispersant increase. By these synergistic effects, it is considered that excellent dispersibility of the calcium carbonate slurry as shown in Table 5 can be expressed.

  On the other hand, although the polymer (C5) has a large amount of phosphorus atoms inserted into the main chain, the molecular weight distribution (Mw / Mn) is wide (Table 3), so that the component having a preferable molecular weight as a dispersant decreases. As shown in Table 5, it is considered that the dispersibility of the calcium carbonate slurry cannot be sufficiently exhibited. In addition, although the polymer (C7) has a narrow molecular weight distribution (Mw / Mn) (Table 3), the amount of phosphorus atoms inserted into the main chain is small (Table 4). It is considered that the dispersibility of the calcium slurry cannot be fully expressed.

  The (meth) acrylic acid polymer of the present invention is suitable for a dispersant, a detergent composition, a water treatment agent, a scale inhibitor and the like.

It is a conceptual diagram explaining the water-soluble polymer manufacturing apparatus in one Embodiment of this invention. It is a conceptual diagram explaining the water-soluble polymer manufacturing apparatus in another embodiment of this invention. It is a conceptual diagram which shows the area ratio obtained by gel permeation chromatography (GPC).

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 (Meth) acrylic acid polymer production apparatus 1 Tank 2 Circulation line 3 Discharge line 4 Cooler 5 Mixing device 6 Circulation pump 7 Alkali agent supply port 8 Monomer supply port 9 Phosphorus-containing compound supply port 10 Polymerization initiator Supply port 11 Agent supply port 12 Stirring means a Tank outlet b Tank return port

Claims (7)

  A (meth) acrylic acid polymer in which the ratio of the amount of phosphorus atoms inserted into the main chain to the amount of phosphorus atoms arranged in the main chain terminal is 3 or more in terms of molar ratio and the molecular weight distribution is 2.8 or less. The monomer component is polymerized while circulating the circulating liquid containing the monomer component including the (meth) acrylic acid-based monomer to the circulation line that comes out of the tank, circulates outside the tank, and returns to the tank. A (meth) acrylic acid polymer obtained by the production method
The circulation line includes a supply port for supplying a phosphorus-containing compound, at least one cooler, and a discharge line for discharging a part of the circulation liquid to the outside of the circulation line;
3 to 7 g of the phosphorus-containing compound is supplied to 1 mol of the (meth) acrylic acid monomer.
(Meth) acrylic acid polymer.   The dispersing agent containing the (meth) acrylic-acid type polymer of Claim 1 or 2.   A detergent composition comprising the (meth) acrylic acid polymer according to claim 1.   A water treatment agent comprising the (meth) acrylic acid polymer according to claim 1.   The scale inhibiting agent containing the (meth) acrylic-acid type polymer of Claim 1 or 2. The monomer component is polymerized while circulating the circulating liquid containing the monomer component including the (meth) acrylic acid-based monomer to the circulation line that comes out of the tank, circulates outside the tank, and returns to the tank. A method for producing a (meth) acrylic acid polymer,
The circulation line includes a supply port for supplying a phosphorus-containing compound, at least one cooler, and a discharge line for discharging a part of the circulation liquid to the outside of the circulation line;
3 to 7 g of the phosphorus-containing compound is supplied to 1 mol of the (meth) acrylic acid monomer.
A method for producing a (meth) acrylic acid polymer.

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