JP2011208027A - Continuous production method of water-soluble polymer and water-soluble polymer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a carboxyl group-containing polymer having excellent dispersibility for an inorganic material and showing sufficient dispersibility with lapse of time.SOLUTION: The water-soluble polymer is produced by a continuous production method including steps of (i) continuously supplying a raw material containing a monomer having a polymerizable unsaturated bond to a reaction device including a tank that can be agitated as an essential component so as to polymerize the raw material and (ii) extracting a part of the reaction liquid from the reaction device, wherein a ratio of the mass of the effective component in the obtained water-soluble polymer composition to the mass of the solid content is not less than 0.9.

Description

The present invention relates to a continuous process for producing a water-soluble polymer. More specifically, the present invention relates to a method for continuously producing a water-soluble polymer useful as a dispersant such as a pigment, a detergent builder, a scale inhibitor, and an inorganic pigment dispersant.

  Water-soluble polymers have excellent basic performance as thickeners, adhesives, flocculants, hygroscopic agents, desiccants, surface modifiers, tackifiers, dispersants, etc. and are widely used in industry. ing. For example, in addition to excavation soil treatment agents, additives for poultices and poultices, dredging treatment agents, pharmaceuticals, paints, papermaking, detergents and cosmetics, water treatment, textile treatment, civil engineering architecture and agriculture / horticulture, adhesives, Widely used in ceramics, manufacturing process and other fields. Further, those having higher quality in terms of viscosity, the amount of remaining monomer, and the like are used for foods and feeds, for example, as thickeners and loosening accelerators.

  As a conventional method for producing a water-soluble polymer, a method for producing high-concentration sodium polyacrylate by batch polymerization with controlled foaming and temperature is disclosed (for example, see Patent Document 1), a cooling device, and the like. A batch reactor with a tank reactor and a stirring mixer is described. However, in this production method, a large-scale apparatus is required to ensure high productivity, and the molecular weight distribution (weight average molecular weight (Mw) / number average molecular weight (Mn)) of the obtained polymer is comparative. For example, when used as an inorganic dispersant, there is room for improvement to improve the dispersibility of the inorganic material and the temporal stability of the dispersibility.

  Moreover, the continuous manufacturing method of the polyacrylate of the low molecular weight distribution which installed the some reactor in series is disclosed (for example, refer patent document 2, patent document 3). In the Examples, a continuous production method of polyacrylate using a stirred tank series continuous reactor having tank-type first to third reactors is disclosed. According to this method, it is disclosed that a polyacrylate having a small content of Michael adduct and a narrow molecular weight distribution can be produced with a high reaction rate. In the reaction apparatus, the stirring tank is connected in series as the first to third reactors, and the reaction liquid is sequentially sent from the first reactor to the third reactor and is taken out from the third reactor. In such a series reaction apparatus, there is room for contrivance in order to be able to produce polyacrylic acid industrially efficiently in terms of shortening the reaction time and heat removal efficiency. Furthermore, the polyacrylic acid salt produced by the above method cannot be said to have a sufficiently small molecular weight distribution. For example, when used as an inorganic dispersant, the dispersibility of the inorganic substance and the stability over time of the dispersibility are reduced. Furthermore, there was room for a device for producing an improved polymer.

  On the other hand, a continuous production method of a water-soluble polymer such as polyacrylic acid having a low molecular weight distribution having a loop-type circulation line is disclosed (for example, see Patent Document 4), a tubular reactor, a motionless A circulation type continuous reaction apparatus having a mixer is described. According to this method, a water-soluble polymer having a relatively small molecular weight distribution can be produced. However, for example, when used as an inorganic dispersant, there is room for devising to produce a polymer with further improved dispersibility of the inorganic material and stability over time of the dispersibility.

  Furthermore, Patent Document 5 discloses that a water-soluble polymer is obtained by circulating a circulating liquid containing a monomer having a polymerizable unsaturated bond in a reactor having a circulation line constituted by a tank and piping that circulates outside the tank. A continuous production method of a water-soluble polymer comprising a step of continuously producing and a step of taking out a part of the circulating liquid from a discharge line, wherein the circulating line is provided with a cooler at at least one place. A continuous process for the production of water-soluble polymers is disclosed. According to the above method, polyacrylic acid having a small molecular weight distribution can be produced efficiently. For example, when used as an inorganic dispersant, the dispersibility of the inorganic substance and the temporal stability of the dispersibility can be further improved. There was room for ingenuity to produce a polymer.

JP 2004-244617 A JP 2003-040912 A JP 2003-002909 A JP 2001-098002 A JP 2007-217654 A

The present invention provides a water-soluble polymer excellent in inorganic dispersibility and the like and exhibiting sufficient dispersibility over time, a water-soluble polymer composition containing the polymer, and a method for easily producing the polymer. For the purpose.

The present inventors have intensively studied to solve the above problems. As a result, it has been found that a specific polymer (composition) produced by a specific continuous production process expresses good dispersibility of an inorganic substance and sufficient dispersibility with stability over time. It came to complete.
That is, the water-soluble polymer composition according to the present invention is polymerized by continuously supplying a raw material containing a monomer having a polymerizable unsaturated bond to a reactor containing (i) a stirrable tank as an essential component. A water-soluble polymer composition produced by a continuous production method comprising the steps of: (ii) removing a part of the reaction liquid from the reaction apparatus, wherein the water-soluble polymer composition obtained The water-soluble polymer composition is characterized in that the number obtained by dividing the mass of the active ingredient by the mass of the solid is 0.9 or more.
From another aspect of the present invention, a method for producing a water-soluble polymer is provided. That is, in the method for producing a water-soluble polymer of the present invention, (i) polymerization is carried out by continuously supplying a raw material containing a monomer having a polymerizable unsaturated bond to a reactor that essentially includes a stirrable tank. And (ii) a step of removing a part of the reaction liquid from the reactor, and a continuous production method of a water-soluble polymer, wherein the mass of the active ingredient in the extracted reaction liquid is the mass of the solid content. A method for producing a water-soluble polymer, wherein the number divided by is 0.9 or more.

The water-soluble polymer and water-soluble polymer composition of the present invention (hereinafter also referred to as water-soluble polymer (composition)) have excellent dispersibility of inorganic fine particles such as mud stains and inorganic pigments, Furthermore, the dispersive power with time can be exhibited. Therefore, when used as a detergent builder or a pigment dispersant, it is possible to obtain excellent detergency over time and dispersibility of the pigment over time.
According to the method for producing a water-soluble polymer of the present invention, the polymer (or the polymer) has excellent dispersibility of inorganic fine particles such as mud stains and inorganic pigments, and can further exhibit dispersibility over time. Composition) can be produced efficiently.

It is a conceptual diagram which shows one Embodiment of the continuous manufacturing method of the water-soluble polymer (composition) of this invention. It is a conceptual diagram which shows one Embodiment of the continuous manufacturing method of the water-soluble polymer (composition) of this invention. It is a conceptual diagram which shows one Embodiment of the continuous manufacturing method of the water-soluble polymer (composition) of this invention.

Hereinafter, the present invention will be described in detail.

[Method for producing water-soluble polymer]
The method for continuously producing a water-soluble polymer of the present invention comprises a step of continuously supplying a raw material containing a monomer having a polymerizable unsaturated bond to a reactor including an agitable tank as an essential component, and performing polymerization. And a step of removing a part of the reaction liquid from the reaction apparatus.

  When the reactor contains a tank as an essential component, the productivity of the water-soluble polymer can be increased, and a desired low molecular weight polymer can be obtained even if the monomer feed amount is increased. In a continuous polymerization method using a tubular reactor having no tank, if a monomer feed amount is increased in order to increase productivity, a desired low molecular weight polymer cannot be obtained. On the other hand, in the present invention, since the reaction apparatus includes a tank, a desired low molecular weight polymer can be obtained even when the monomer feed amount is increased, and can be produced with high productivity. .

  The tank preferably has a nozzle for supplying additives such as a polymerization initiator, a polymerization accelerator and a chain transfer agent. That is, it is preferable to add a polymerization initiator, a polymerization accelerator, and a chain transfer agent to advance the polymerization. It is preferable that the polymerization reaction proceeds mainly. Mainly means that 90 mol% or more of the monomer used reacts in the tank.

The tank is preferably provided with stirring means. The stirring means is not limited, but more preferably any suitable stirring means that can stir the reaction liquid in the tank with a required power Pv of 0.5 kW / m ³ or more can be adopted. By stirring the reaction solution in the tank with the above stirring power, the dispersibility of the resulting water-soluble polymer inorganic particles and the dispersibility over time tend to be improved. 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 water-soluble polymer having a narrow molecular weight distribution can be obtained even on an industrial scale production line. In general, the stirring device includes a drive unit, a transmission unit, and a stirring blade. As the drive unit and the transmission unit, those having any appropriate shape and / or mode can be adopted, and those capable of obtaining a desired power Pv for stirring are preferable. 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 material of the production apparatus of the present invention is preferably made of SUS from the viewpoint of heat transfer and corrosion resistance, and specific examples include SUS304, SUS316, SUS316L, and the like. In these cases, it is also possible to apply a conventionally known scale inhibitor or add this (a conventionally known scale inhibitor) to the reaction solution (the reaction solution may be suspended). The same applies to various supply ports that may be installed in the manufacturing apparatus of the present invention.

In the method for producing a water-soluble polymer of the present invention, it is preferable to set the residence time of the reaction liquid in the reaction apparatus (tank (circulation line described later when applicable)) to 240 minutes or less. By setting the residence time as described above, the dispersibility of the resulting polymer inorganic particles and the dispersibility over time tend to be improved.
More preferably, it is 150 minutes or less, and is 1 minute or more. More preferably, it is 120 minutes or less, and is 2 minutes or more. Especially preferably, it is 90 minutes or less, and is 3 minutes or more. The “residence time” is calculated by the following formula.
Residence time (minutes) = total amount of reaction solution (parts by mass) / discharged amount outside reaction apparatus per unit time (parts by mass / minute)
In the method for producing a water-soluble polymer of the present invention, the polymerization concentration is preferably set to 1 to 30% by mass. By setting the polymerization concentration as described above, the dispersibility of the resulting polymer inorganic particles and the dispersibility over time tend to be improved.
More preferably, it is 25 mass% or less, and is 5 mass% or more. More preferably, it is 20 mass% or less, and is 8 mass% or more. Especially preferably, it is 18 mass% or less, and is 10 mass% or more. In the present invention, “polymerization concentration” refers to the mass% of the monomer used relative to 100 mass% of the reaction solution. Here, when the polymerization concentration is calculated, when the monomer is an acid group-containing monomer, the polymerization concentration is calculated using the mass converted to the acid type. For example, when the acid group-containing monomer is “sodium acrylate”, the polymerization concentration is calculated as “acrylic acid” which is the corresponding acid. The acid group-containing monomer is a monomer having an acid group or a salt thereof, such as an unsaturated carboxylic acid monomer or a monoethylenically unsaturated monomer having a sulfonic acid group, which will be described later. Illustrated.

In the method for producing a water-soluble polymer of the present invention, the monomer used (monomer composition) contains an acid group-containing monomer, but the degree of neutralization of the acid group-containing monomer. Is preferably 50 mol% or more and 100 mol% or less. By setting the neutralization degree of the acid group-containing monomer as described above, the dispersibility of the resulting polymer inorganic particles and the dispersibility over time tend to be improved. More preferably, it is 60 mol% or more and 100 mol% or less. More preferably, it is 65 mol% or more and 100 mol% or less. Especially preferably, it is 70 mol% or more and 100 mol% or less.
The degree of neutralization of the acid group-containing monomer may be adjusted by adding an acid type acid group-containing monomer and a salt of the acid group-containing monomer at a predetermined rate. You may adjust by adding a group-containing monomer and an alkaline substance at a predetermined rate.

In the method for producing a water-soluble polymer of the present invention, the reaction temperature (the temperature of the reaction solution in the tank) is preferably 0 to 150 ° C. By setting the reaction temperature as described above, sufficient productivity can be achieved, and the dispersibility of the resulting polymer inorganic particles and the dispersibility over time tend to be improved.
More preferably, it is 50 degreeC or more and 130 degrees C or less. More preferably, it is 70 degreeC or more and 125 degrees C or less. Especially preferably, it is 80 degreeC or more and 120 degrees C or less.

Although the said reaction apparatus is not essential, it is preferable to have a circulation line comprised by the tank and piping which circulates the exterior. When the reactor has a circulation line, the dispersibility of the resulting polymer inorganic particles and the dispersibility over time tend to be further improved.
Therefore, the essential step of the continuous production method of the water-soluble polymer of the present invention is “continually supplying a raw material containing a monomer having a polymerizable unsaturated bond to a reactor containing a stirrable tank as an essential component. In the step of performing polymerization, “a raw material containing a monomer having a polymerizable unsaturated bond is continuously supplied to a reactor having a circulation line composed of a stirrable tank and piping circulating outside thereof. And the step of carrying out polymerization ".

  In the production method of the present invention, when the reaction apparatus is a reaction apparatus having a circulation line constituted by a stirrable tank and piping circulating outside thereof, it is not essential, but it is preferable to circulate the reaction liquid. The circulation ratio obtained by dividing the amount of liquid returning to the tank by the amount of liquid extracted from the discharge line to the outside of the manufacturing apparatus (the amount of liquid returning to the tank / the amount of liquid extracted outside) is preferably 3 or more. When the circulation ratio is 3 or more, a water-soluble polymer having a small concentration gradient and a narrow Mw / Mn can be obtained while maintaining high productivity. The circulation ratio is more preferably 5 or more, still more preferably 9 or more, and particularly preferably 10 or more.

In the production method of the present invention, the supply rate of the monomer to be supplied into the tank (the circulation line, if applicable) is set to a rate that satisfies the residence time. The supply rate can be increased if the capacity of the tank (where applicable, the circulation line) is increased.
When the reactor has a pipe that circulates outside the tank in addition to the tank (that is, when the reactor has a circulation line constituted by the tank and the pipe that circulates outside the tank), the tank has a sufficient volume compared to the pipe. It is preferable. In this case, since the reaction liquid returns to the tank and circulates, the tank is also called a recycling tank in the meaning of the circulating liquid tank. When the reactor has a pipe that circulates outside the tank in addition to the tank, the volume of the tank is preferably 10% by volume or more of the entire circulation line. When the volume of the tank is less than 10% by volume, there is a problem that the piping becomes very long, and from the viewpoint of the pressure loss and the like accompanying it, it does not function sufficiently as a reactor in which the polymerization reaction proceeds, The productivity of the conductive polymer may not be sufficiently increased. More preferably, it is 30 volume% or more.
Even when the reactor has a circulation line composed of a tank and piping that circulates outside the tank, the tank not only holds and circulates the circulating liquid, but also functions as a reactor in which the polymerization reaction proceeds as described above. It is preferable to do.

  The piping that circulates outside the tank is connected to the tank outlet (circulating fluid outlet) and the tank inlet (circulating fluid inlet) to form a circulation line (loop structure) together with the tank. 1 and 2, which is an example of a preferred embodiment of the present invention, if the tank bottom (tank outlet) in FIGS. 1 and 2 is a, and the place returning to the tank top (tank inlet) is b, The section indicated by a to b is referred to as “piping circulating outside the tank”.

  In the above piping, not only the circulating liquid is retained and circulated but also the polymerization reaction usually proceeds.

  The tank preferably comprises a condenser and / or a cooler. It is preferable that the tank is provided with a condenser and / or a cooler because excessive heat history is suppressed and the dispersive power with time of the obtained polymer tends to be improved.

When the reaction apparatus has a circulation line, it is preferable that the piping that circulates outside the tank includes a cooler in at least one place. By providing a cooler, reaction heat generated from polymerization heat, dilution heat, heat of neutralization, heat of decomposition, heat of dissolution, etc. can be efficiently removed, and the temperature distribution in the reactor should be uniform. In addition, since the temperature can be easily controlled, a water-soluble polymer having a narrower Mw / Mn tends to be obtained. The cooler is preferably one that can lower the temperature of the circulating fluid passing through the cooler and remove at least several percent of the heat of reaction. For example, it can remove 30% or more of the generated heat of reaction. It is preferable that If the removal of reaction heat is sufficient, Mw / Mn of the resulting water-soluble polymer tends to be sufficiently narrow. More preferably, 50% or more can be removed, and still more preferably 70% or more can be removed. As the cooler, it is preferable that the relationship between the volume V [m ³ ] of the circulating fluid and the heat transfer area S [m ² ] of the cooler satisfies S / V ≧ 5. When the cooler satisfies such requirements, the circulating fluid can be sufficiently cooled, and the effects of the present invention can be exhibited. More preferably, it is 6.5 or more, and more preferably 8 or more. As the cooler, it is preferable that at least one of the reaction heat removal efficiency and S / V satisfies the above requirements, and it is more preferable that both satisfy both requirements.

  In the present invention, for example, (meth) acrylic acid, its salts, esters, etc., acrylamide and its N-substituted product, etc. can be suitably applied to the reaction that proceeds rapidly. Polymerization reaction. In particular, in the polymerization reaction of acrylic acid and / or its salt, as described later, depending on the reaction conditions such as the initiator used, the reaction is faster as 90% or more of the raw material is converted into a water-soluble polymer in 30 seconds. Since the reaction heat accompanying it is also large, it is preferable to provide a cooler for removing the reaction heat in a circulation line constituted by a tank and piping circulating outside thereof.

  When a cooler is provided in a circulation line constituted by a tank and piping that circulates outside the tank, the shape, type, number of installation, installation position, etc. are not particularly limited as the structure of the cooler. As the shape and form of the cooler, for example, a multi-tube cylindrical type, a double-pipe type, a plate type, an air cooler, an irrigation cooler, a coil type, a spiral type, a jacket, etc. Any of them may be adopted, and they can be used alone or in combination. In the case of a jacket or the like, the length in contact with the pipe or the tank is not particularly limited. The number of installed coolers may be one or plural. In the case of a plurality of installations, a plurality of installations may be provided at one place or may be arranged in a distributed manner, but a distributed arrangement with good cooling efficiency is preferable. For example, when a large amount of reaction heat is generated, it is preferable to disperse and install a plurality.

  As described above, the tank is preferably provided with stirring means, but when the reaction apparatus has a circulation line constituted by the tank and piping circulating outside thereof, in order to make the concentration distribution of the raw material of the reaction solution uniform, It is preferable that at least one apparatus for mixing the reaction liquid is installed in a pipe that circulates outside the tank. The mixing device is preferably a motionless mixer, but a configuration in which a stirrer is installed (a mode in which a stirrer type reaction device is installed in the middle of a pipe circulating outside the tank) or a pipe that circulates outside the tank is used. The form etc. which mix from the outside by external forces, such as an ultrasonic wave, may be sufficient. Among these, by installing a motionless mixer with excellent stirring ability in the piping that circulates outside the tank, the reaction solution, raw materials, initiators described later, etc. are mixed more efficiently, and the concentration gradient decreases. There is an advantage that the reaction solution can be made more uniform. Thus, the form in which the piping circulating outside the tank has the motionless mixer is one of the preferred forms of the present invention. In addition, you may use the said stirring apparatus in combination of 2 or more types.

  In the above manufacturing method, the installation position of the raw material supply port is not particularly limited as long as the effects of the present invention are exhibited, and may be any position in the manufacturing apparatus (tank, circulation line if applicable). However, when the reaction apparatus has a circulation line, it is preferable that the raw material supply port is provided in a pipe circulating outside the tank. The number of installed raw material supply ports is not particularly limited, and may be at least one. Thus, the form in which the piping circulating outside the tank is provided with the raw material supply port in at least one place is one of the preferred forms of the present invention.

  In the production method of the present invention, when the reactor has a circulation line, the conversion rate indicating the monomer conversion amount at the tank inlet with respect to the monomer addition amount at the raw material supply port is 90% or more. Is preferred. If it is less than 90%, there are many residual monomers and the productivity may be lowered. More preferably, it is 92% or more, More preferably, it is 93% or more. For example, when using sodium acrylate as a monomer and obtaining sodium polyacrylate (PSA), the conversion rate can be varied in various amounts of initiator amount, transfer agent amount, accelerator amount, temperature, and residence time. It can be calculated based on the Arrhenius equation from the simulation result obtained by the reaction rate analysis. In the case of a copolymer such as (meth) acrylic acid (salt) / (meth) acrylic acid ester in a continuous stirred tank reactor (CSTR), the conversion rate is a homogeneity such as PSA. Although it may be different from the case of the polymer, the preferable range of the conversion is as described above. Details of the monomer will be described later.

  In the production method of the present invention, the polymerization reaction can be performed even under pressure. By carrying out the polymerization reaction under pressure, the reaction can be carried out at a high temperature. By promoting the reaction, there are few residual monomers and an improvement in productivity can be expected. The polymerization reaction can be performed under pressure, for example, by controlling the flow rate or temperature of the reaction solution. Although it does not specifically limit as said pressure, 0.1 MPa-3.0 MPa are preferable. More preferably, it is 0.12 MPa to 1.0 MPa.

  The polymerization temperature (reaction temperature) in the production method of the present invention is as described above for the temperature of the reaction kettle (tank), but when the reaction apparatus has a circulation line, the temperature of the piping circulating outside the tank is The temperature difference between the inlet (immediately after leaving the tank) and the outlet of the piping circulating outside the tank (immediately before returning to the tank) is preferably within 25 ° C.

The polymerization temperature may fluctuate over time during the polymerization (temperature increase or decrease), and may be temporarily out of the preferred polymerization temperature range at the start of polymerization. However, it is preferable to suppress the temperature fluctuation as much as possible, for example, it is preferable to suppress it to 25 ° C. or less. When the temperature variation is within 25 ° C., a narrow Mw / Mn polymer can be obtained, and the decomposition rate of the polymerization initiator can be made constant, so that uniform polymerization can proceed. More preferably, it is within 20 degreeC, More preferably, it is within 18 degreeC.
The polymerization reaction can be carried out in air, in an inert gas atmosphere such as nitrogen or argon, or in a reactive gas atmosphere derived from a chain transfer agent or the like.
The temperature of the reaction product is detected by a temperature sensor, the temperature of the heat exchanger is adjusted according to the detected value, and the temperature in the reaction vessel (manufacturing apparatus or reaction apparatus) becomes the target polymerization temperature (for example, T ° C It is preferable to carry out the polymerization while controlling the feedback so that it substantially coincides with A preferred guideline for the control range is T ° C. ± 10 ° C. More preferably, T ° C. ± 7 ° C., and further preferably T ° C. ± 5 ° C.
In the temperature control by the feedback control, when the production apparatus for the polymer solution is 1 m ³ or more, the heat radiation from the reactor surface is reduced. Therefore, when the reaction apparatus has a circulation line, the heat removal by the circulation line is particularly important. The effect is easy to appear and it can be suitably used. More preferably, it is 3 m ³ or more, and further preferably 5 m ³ or more. In this case, if it is necessary to keep the circulating fluid warm, control the temperature of the heat medium (or refrigerant) flowing in the jacket of the motionless mixer, control the monomer supply, And heat supply to piping and tanks as necessary.

In the production method of the present invention, the reaction apparatus may have a supply port for supplying other components as necessary. The supply port for the other components is not particularly limited as long as the effect exerted by adding the other components is obtained, and any one or more may be installed in the reaction apparatus, for example, as desired. In order to improve the reaction efficiency of the polymer, the reaction apparatus may have an inlet through which a reaction accelerator, an alkali agent, or the like can be introduced into a tank (in any of the circulation lines if applicable). .
As said other component, it is also possible to add a crosslinking agent in the range with which an alkali agent, a polymerization accelerator, a chain transfer agent, and a polymer maintain water solubility.
By supplying the alkaline agent, the pH of the circulating liquid can be appropriately changed, and the neutralization rate of the monomer can be changed. Moreover, by using a polymerization accelerator and a chain transfer agent, it is possible to control the polymerization reaction and narrow the Mw / Mn of the resulting water-soluble polymer.

When an alkali agent, a polymerization accelerator, or a chain transfer agent is used as the other component, the supply port for the other component is preferably located in the circulation line when the reaction apparatus has a circulation line. That is, the tank (circulation line, if applicable) is (1) an embodiment provided with an alkali agent supply port and / or (2) an embodiment provided with a polymerization accelerator supply port, And / or (3) a mode in which a chain transfer agent supply port is provided. In the case where the reaction apparatus has a circulation line, these supply ports are preferably located between the discharge line and the tank in the direction of the reaction liquid flow path. When the tank, discharge line, and cooler are arranged in this order in the flow direction of the reaction liquid in the circulation line, it is located between the cooler and the tank or between the discharge line and the cooler. Preferably it is located.
The production method of the present invention includes a step of taking a part of the reaction solution from the reaction apparatus. Therefore, it is preferable that the manufacturing apparatus used for the manufacturing method of the present invention includes a discharge device (also referred to as a discharge line). That is, the “step for removing a part of the reaction solution from the reaction apparatus”, which is an essential step of the continuous production method of the water-soluble polymer of the present invention, is a “step for removing a part of the reaction solution from the discharge line”. It is preferable.

In the production method of the present invention, when a part of the reaction solution is taken out from the discharge line, the reaction apparatus has at least one discharge line. The installation position of the discharge line is not particularly limited as long as the effect of the present invention is exhibited, and may be any position of the reaction apparatus (tank, circulation line if applicable), but the reaction apparatus is circulated. When it has a line, it is preferable that it is installed in piping circulating outside the tank in consideration of the ease of maintenance by simplifying the line and cost. More preferably, when the circulation line has a cooler, the discharge line is positioned between the tank and the cooler in the direction of the circulating fluid flow path from the viewpoint of simplifying the piping path and simplifying the equipment. It is located between the tank and the raw material supply port. When the tank, the cooler, and the raw material supply port are arranged in this order in the direction of the circulating fluid flow path, it is more preferable that the tank is located between the tank and the cooler. Moreover, when a tank, a raw material supply port, and a cooler are arrange | positioned in this order, it is still more preferable to be located between a tank and a raw material supply port. By installing in such a position, it is possible to take out the solution in which the monomer concentration of the circulating liquid is the lowest in the circulation line and the polymerization is most advanced.
The discharge line preferably has a motionless mixer and / or a stirred reactor (hereinafter also referred to as a motion-lens mixer or the like). In this way, by providing at least one motionless mixer or the like in the discharge line, it is possible to easily perform steps such as addition of an initiator for removing the residual monomer and neutralization of the polymer if applicable. .

  The discharge line is preferably provided with a cooler in at least one place. By providing a cooler in the discharge line, it is possible to sufficiently remove heat from the resulting product, and there is an advantage that the apparatus can be simplified when there are post-processes such as monomer removal and neutralization in the polymer. is there. Further, as will be described later, even if the discharge line is provided with the raw material supply port, the reaction heat can be sufficiently removed, so that the mixture of the circulating liquid and the raw material taken out from the discharge line can be heated to an appropriate temperature. It can be. As the cooler that can be provided in such a discharge line, the above-described cooler is preferable.

  The discharge line is preferably provided with a raw material supply port and has a mechanism in which the circulating liquid is mixed with the raw material and taken out. Thus, by providing at least one raw material supply port in the discharge line, for example, by additionally supplying a polymerization initiator or the like from the supply port, the residual monomer contained in the obtained water-soluble polymer can be reduced. There is an advantage that the level can be made extremely low. When installing a cooler, a motionless mixer, etc. in a discharge line, the form which installs a raw material supply port in at least one location of upstream, such as a cooler, a motionless mixer, etc. is preferable. When both a cooler and a motionless mixer are installed, it is preferable to provide a cooler upstream of the motionless mixer and provide a raw material supply port between the cooler and the motionless mixer. FIG. The form is shown.

  The discharge line may further have a supply port for supplying other components. When an alkali agent, a polymerization accelerator, or a chain transfer agent is used as the other component, the discharge line is (1) a form in which an alkali agent supply port is provided, and / or (2) a polymerization accelerator. A form in which a supply port is provided and / or (3) a form in which a chain transfer agent supply port is provided are suitable.

  When the discharge line includes a cooler and / or a motionless mixer, the other component supply port is preferably between the cooler and the motionless mixer in the direction of the circulating fluid flow path. When there are a plurality of supply ports for other components, the installation positions can be set as appropriate.

  Thus, the discharge line may be supplied with one or more agents selected from the group consisting of alkaline agents, raw materials (initiators, etc.), chain transfer agents, polymerization initiators and oxidizing agents. Other components may be supplied to the discharge line. Such a supply port may be provided at one place or two or more places on the discharge line.

  1 and 2 show a form in which one such agent supply port for supplying various agents and the like is provided between the cooler and the motionless mixer in the direction of the circulating fluid flow path.

  The production method of the present invention is characterized in that the number obtained by dividing the active ingredient of the water-soluble polymer composition obtained by the production method of the present invention by the solid content is 0.9 or more. Such a polymer exhibits good dispersibility of inorganic particles and dispersibility over time. Preferably it is 0.905 or more and 1 or less, 0.91 or more and 1 or less is more preferable, and 0.915 or more and 1 or less is especially preferable. According to the production method of the present invention, the water-soluble polymer (composition) can be produced.

[Water-soluble polymer and water-soluble polymer composition of the present invention]
The water-soluble polymer (composition) of the present invention is preferably produced by the above production method. The water-soluble polymer of the present invention is characterized in that the number obtained by dividing the active ingredient of the water-soluble polymer (composition) by the solid content is 0.9 or more.
In this invention, an active ingredient and solid content are calculated by the method shown below.

<Method for measuring active ingredient>
Measuring instrument: Hiranuma Sangyo Co., Ltd. automatic titrator "COM-1500"
Indicator electrode: “GE-101B” manufactured by Hiranuma Sangyo Co., Ltd.
Reference electrode: “RE-201” manufactured by Hiranuma Sangyo Co., Ltd.
Analysis software: "Titration Mimee ver. 1.13" manufactured by the same company
Measurement procedure:
(I) About 5 g of an aqueous polymer solution is weighed (Ag in the following formula).
(Ii) Add about 100 g of distilled water to the above and stir.
(Iii) About 5 ml of 1 mol / l sodium hydroxide (Wako Pure Chemical Industries, Ltd. (for volumetric analysis)) is added with stirring.
(Iv) While stirring, 1 mol / l hydrochloric acid (manufactured by Wako Pure Chemical Industries, Ltd. (for volumetric analysis)) is added with the automatic titrator (the titer is assumed to be f). Continue titration until the pH of the system is 1.5.
(V) The obtained inflection point (neutralization point) data is derived by the analysis software (in the inflection point detection mode).
(Vi) Record the titration amount (drop amount pml up to the first neutralization point, enemy quantitative qml up to the second neutralization point) when showing the inflection point, and use the following calculation formula (1) to determine the active ingredient Is calculated.
(Vii) The above (i) to (vi) are carried out twice for the same sample, and the average value is used as the active ingredient. In addition, the said measurement is implemented at 25 degreeC.

However, in the above formula,
X (%): active ingredient M (g / mol): average molecular weight after neutralization (however, converted to monovalent acid)
f: titer of 1 mol / l hydrochloric acid q (ml): 1 mol / l hydrochloric acid dropwise to the second neutralization point p (ml): 1 mol / l to the first neutralization point
A (g): mass of collected polymer.

<Method for Measuring Solid Content of Polymer (Composition)>
The non-volatile content after 2 hours with a hot air dryer at 110 ° C. was defined as the solid content. It attached to the same polymer, measured three, and the average value of the obtained non-volatile content was made into solid content.

  According to the production method of the present invention, a water-soluble polymer having a narrow Mw / Mn can be obtained, but when used as a detergent builder, dispersant, scale inhibitor, etc., the weight average molecular weight (Mw) is 1500-500. 30000 is preferred, 2000-20000 is preferred, 2000-12000 is more preferred, and 2000-10000 is even more preferred. When Mw / Mn is narrowed in this molecular weight range, more polymers having the same degree of polymerization can be obtained. For example, the dispersant has a favorable influence on the performance of the agent, such as improved 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 2.7 or less.

The number average molecular weight (Mn), weight average molecular weight (Mw) and Mw / Mn of the polymer can be obtained by GPC (gel permeation chromatography) measurement. The measurement conditions are as follows.
<GPC measurement conditions>
G-3000PWXL (trade name) manufactured by Tosoh Corporation was used as a GPC column.
As a mobile phase, pure water was added to 34.5 g of disodium hydrogen phosphate 12 hydrate and 46.2 g of sodium dihydrogen phosphate dihydrate (both of which are reagent-grade) to make a total amount of 5000 g, and then 0. An aqueous solution (solid content: 0.1% by mass) filtered through a 45 μm membrane filter is used.
As the detector, L-7110 (trade name) manufactured by Hitachi, Ltd. was used, and the detection wavelength was 214 nm. Measurement is performed in the UV measurement mode.
The pump used was L-6000 manufactured by Hitachi, Ltd., the mobile phase flow rate was 0.5 ml / min, and the temperature was 35 ° C. A calibration curve is created 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 the present invention, the water-soluble polymer means a polymer having a structure derived from a monomer (unsaturated carboxylic acid monomer) having a carboxylic acid group and / or a salt thereof. 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. Preferred forms in the case of a salt are alkali metal salts such as sodium and potassium and ammonium salts, particularly preferably sodium salts and ammonium salts. Here, the structure derived from the unsaturated carboxylic acid monomer is a structural unit formed by radical polymerization of the unsaturated carboxylic acid monomer. For example, the structural unit derived from acrylic acid is a structural unit represented by —CH ₂ CH (COOH) —.

  The raw material that can be suitably used for the production of the water-soluble polymer of the present invention is not particularly limited as long as the water-soluble polymer can be produced. For example, an unsaturated carboxylic acid monomer is preferred, but an unsaturated carboxylic acid ester monomer or the like, such as a monomer capable of forming a structure derived from an unsaturated carboxylic acid monomer by hydrolysis or the like. good. Moreover, it is preferable that the manufacturing method of this invention is a method of using the raw material which contains an unsaturated carboxylic acid-type monomer as an essential. When the water-soluble polymer of the present invention has a structure derived from an unsaturated carboxylic acid monomer, the dispersibility of inorganic particles and the dispersibility over time of the resulting polymer tend to be improved.

  The unsaturated carboxylic acid monomer (hereinafter also referred to as monomer (I)) may be any monomer having a polymerizable unsaturated group and a group capable of forming a carbanion. Is a compound represented by the following 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⁾ z1COOM 2, z1 represents the number of 0 to 3. - _(CH 2) z1COOM ² is, -COOM ¹ or another _- (CH 2) _z1COOM may form a 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).

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 the monomer (I), an unsaturated monocarboxylic acid-based monomer, an unsaturated dicarboxylic acid-based monomer, and the like are preferable. Any monomer that has one saturated group and one group capable of forming a carbanion may be used, for example, acrylic acid, methacrylic acid, crotonic acid, α-hydroxyacrylic acid, etc .; these monovalent metal salts, 2 Preferred are valent metal salts, ammonium salts and organic amine salts.
The unsaturated dicarboxylic acid-based monomer may be any monomer having one unsaturated group and two groups capable of forming a carbanion in the molecule, such as maleic acid, itaconic acid, citraconic acid, Fumaric acid and the like, monovalent metal salts, divalent metal salts, ammonium salts and organic amine salts thereof, or anhydrides thereof are preferable.
As the monomer (I), in addition to these, a half ester of an unsaturated dicarboxylic acid monomer and an alcohol having 1 to 22 carbon atoms, an unsaturated dicarboxylic acid and one having 1 to 22 carbon atoms Half amides with amines, half esters of unsaturated dicarboxylic acid monomers and glycols having 2 to 4 carbon atoms, half amides of maleamic acid and glycols having 2 to 4 carbon atoms, α- (hydroxyalkyl) acrylic acid (Salt), α- (hydroxypolyalkyleneoxymethyl) acrylic acid (salt) and the like can also be used.
As the monomer (I), one or more of the above-exemplified examples can be suitably used. Among them, (meth) acrylic acid (salt), from the viewpoint of high polymerizability and versatility, Maleic acid (salt), maleic anhydride, itaconic acid (salt), and α-hydroxyacrylic acid (salt) are preferable, and (meth) acrylic acid and maleic acid (salt) are more preferable. More preferred is (meth) acrylic acid (salt). In addition, (meth) acrylic acid (salt) refers to (meth) acrylic acid and a partial or completely neutralized salt such as monovalent metal salt, divalent metal salt, ammonium salt or organic amine salt thereof. .
The monomer component capable of producing the water-soluble polymer can be copolymerized with other monomers (the unsaturated carboxylic acid monomer (monomer (I)) other than the monomer (I). Monomer (hereinafter also referred to as monomer (II)) can be preferably used.
The monomer (II) may be any monomer copolymerizable with the monomer (I), such as vinyl sulfonic acid, allyl sulfonic acid, 3-allyloxy-2-hydroxypropane sulfonic acid, isoprene. Monoethylenically unsaturated monomers having a sulfonic acid group such as sulfonic acid, 2-acrylamidomethylpropanesulfonic acid, styrenesulfonic acid, and 2-sulfoethyl methacrylate, and monovalent metal salts, divalent metal salts thereof, Partially or completely neutralized salts such as ammonium salts and organic amine salts; 3-methyl-2-buten-1-ol (also simply referred to as prenol), 3-methyl-3-buten-1-ol (simply simply isoprenol) Also called unsaturated hydrocarbons containing hydroxyl groups such as (meth) allyl alcohol, isoprenol and allyl alcohol. It was added Sid unsaturated polyalkylene glycol monomer, and the like.

  As said monomer (II), a radically polymerizable monomer can also be used conveniently. The radical polymerizable monomer is not particularly limited as long as it is a radical polymerizable monomer. For example, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, (meth) acrylic Hexyl acid, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, tridecyl (meth) acrylate, stearyl (meth) acrylate, cyclohexyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, ( Mono (meth) acrylates such as ethyl aminoethyl acrylate, glycidyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, allyl (meth) acrylate; triethylene glycol di (meth) acrylate, tetraethylene Glycol di (meth) acrylate, pentylglyco Rudi (meth) acrylate, dipropylene glycol di (meth) acrylate, trimethylolpropane di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, etc. (Meth) acrylates such as polyvalent (meth) acrylates; alkoxy polyalkylene glycol (meth) acrylates, polyalkylene glycol (meth) acrylates.

Aromatic monomers such as styrene and α-methylstyrene; vinyl esters such as vinyl acetate and vinyl propionate; vinyl ethers such as hydroxymethyl vinyl ether, hydroxyethyl vinyl ether, hydroxypropyl vinyl ether, and hydroxybutyl vinyl ether; N-vinyl Monomers having a nitrogen-containing functional group such as pyrrolidone and acryloylmorpholine; Nitrile group-containing monomers such as (meth) acrylonitrile; Amide monomers such as (meth) acrylamide and N-methylolacrylamide; Preferred monomers include hydroxyl group-containing monomers such as 2-hydroxyethyl acrylate; epoxy group-containing monomers such as glycidyl (meth) acrylate.
As said monomer (II), 1 type (s) or 2 or more types can be selected suitably and used.

  The blending amount of the monomer (I) is in the range of 50 to 100 mol%, preferably 70 to 100 mol%, more preferably 90 to 100 mol%, based on the total amount of monomers. When the amount of monomer (I) is 50 mol% or more, in many cases, water solubility can be widely expressed, which is preferable. On the other hand, the upper limit may be 100 mol%.

  The monomer (I) may be added in the form of a solution (preferably an aqueous solution) of the monomer (I) after being dissolved in a solvent described later, preferably water. The concentration when used as a monomer (I) solution (preferably an aqueous solution) is 30 to 75% by mass, preferably 35 to 70% by mass, and more preferably 40 to 65% by mass. When the concentration of the monomer (I) solution is within this range, a product with a good concentration can be obtained, which is preferable in terms of transportation and storage.

  It is preferable that the compounding quantity of the said monomer (II) is 0-50 mol% with respect to the monomer whole quantity. More preferably, it is 0-30 mol%, More preferably, it is 0-10 mol%. When the blending amount of the (II) is 50 mol% or less, the physical properties of the monomer (II) alone or in cooperation with the monomer (I) can be expressed as a polymer while maintaining water solubility. . On the other hand, the lower limit of the monomer (II) is 0 mol%. That is, any of a homopolymer (copolymer) or a copolymer (copolymer) based on the monomer (I) component may be used.

  The monomer (II) may be added in the form of a solution (preferably an aqueous solution) of the monomer (II) after being dissolved in a solvent described later, preferably water. The concentration when used as a monomer (II) solution (preferably an aqueous solution) is 10 to 100% by mass, preferably 20 to 95% by mass, more preferably 30 to 90% by mass. When the concentration of the monomer (II) solution is 10% by mass or more, a product with a good concentration can be obtained, which is preferable in terms of transportation and storage. On the other hand, the upper limit is not particularly limited, and may be 100% by mass (that is, the total amount) of monomer (II) (that is, no solvent).

  The water-soluble polymer (composition) of the present invention is produced using a solvent. 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 One type or two or more types of hydrocarbon solvents such as can be appropriately selected and used.

  The solvent is preferably an aqueous solvent such as water, alcohol, glycol, glycerin or polyethylene glycol. More preferably, it is 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 material, and the like, and is usually preferably 10% by mass or less.

  As described above, the amount of the solvent used is preferably 60 to 99% by mass, preferably 70 to 95% by mass with respect to 100% by mass of the total reaction solution, because the polymerization concentration is preferably set to 1 to 30% by mass. More preferably, it is the range of 75-90 mass%. When the amount of the solvent used is less than 60% by mass, the molecular weight becomes high. On the other hand, when the amount of the solvent used exceeds 99% by mass, the concentration of the produced water-soluble polymer is low. In some cases, it is not preferable because solvent removal is required. A part of the solvent may be appropriately added to the reaction system alone during the 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.

  As the polymerization initiator that can be used in the production method of the present invention, a redox initiator, an azo-based initiator, an organic peroxide, a photoinitiator and the like are suitable. Specifically, persulfates such as sodium persulfate, ammonium persulfate, and potassium persulfate; hydrogen peroxide; 2,2′-azobis (2-aminodipropane) dihydrochloride, 4,4′-azobis (4 -Cyanovaleric acid), azo-based compounds such as azobisisobutylnitrile, 2,2'-azobis (4-methoxy-2,4-dimethylvaleronitrile); benzoyl peroxide, lauroyl peroxide, peracetic acid, persuccinic acid, Examples thereof include organic peroxides such as di-t-butyl peroxide, t-butyl hydroperoxide and cumene hydroperoxide. These may be only one type or two or more types. Among these, redox initiators, azo initiators, and organic peroxides are preferable. Specifically, persulfate, hydrogen peroxide, organic peroxide, 2,2′-azobis (2-aminodipropane) dihydrochloride is preferable, and persulfate, hydrogen peroxide, 2,2′- Azobis (2-aminodipropane) dihydrochloride is more preferable, and persulfate and hydrogen peroxide are more preferable.

  In combination with the polymerization initiator, a simple metal, a salt and / or a complex containing a metal having a plurality of oxidation numbers as a constituent component may be used (also referred to as a heavy metal-containing compound). As described above, the above production method is a continuous production method of a water-soluble polymer comprising a metal simple substance, a salt and / or a complex containing a metal having a plurality of oxidation numbers as a constituent component from at least one place of a supply port. Is also one of the preferred embodiments of the present invention. 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. If there is a plurality of oxidation numbers, the type of the metal is not limited if it is used to promote the reaction, but considering that the reaction system is not complicated, it is a metal component having two types of oxidation numbers. More preferred are simple metals, salts and / or complexes. 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, vanadium oxytrichloride, vanadium trichloride, vanadyl oxalate, vanadyl sulfate, vanadic anhydride, ammonium metavanadate, ammonium sulfate hypovanadas [(NH4) 2SO4 · VSO4 · 6H2O], ammonium sulfate vanadas [(NH4 ) V (SO4) 2 · 12H2O], copper acetate (II), copper bromide (II), copper (II) acetyl acetate, cupric ammonium chloride, ammonium copper chloride, copper carbonate, copper chloride (II), citrate Copper (II) acid, copper (II) formate, copper (II) hydroxide, copper nitrate, copper naphthenate, copper (II) oleate, copper maleate, copper phosphate, copper (II) sulfate, first chloride Copper, copper cyanide (I), copper iodide, copper oxide (I), copper thiocyanate, iron acetyl acetonate, ammonium iron citrate, second oxalic acid Ammonium, ammonium iron sulfate (Mole salt), ferric ammonium sulfate, iron citrate, iron fumarate, iron maleate, ferrous lactate, ferric nitrate, iron pentacarbonyl, ferric phosphate, pyrophosphate Water-soluble polyvalent metal salts such as ferric iron; polyvalent metal oxides such as vanadium pentoxide, copper (II) oxide, ferrous oxide, ferric oxide; iron (III) sulfide, iron (II) sulfide It is preferable that it is 1 type, or 2 or more types, such as polyvalent metal sulfides, such as copper sulfide; 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.
It is preferable that the metal simple substance, salt and / or complex containing the metal having a plurality of oxidation numbers as a constituent component is added from the above-described polymerization initiator supply port, and the arrangement and installation of the polymerization initiator supply port The number and the like are as described above.

  As said other initiator, a chain transfer agent may be used and the molecular weight of a polymer can be adjusted by using a chain transfer agent. The chain transfer agent is not particularly limited, and sulfurous acid (salt), hydrogen sulfite (salt), pyrosulfurous acid (salt), phosphorous acid (salt), hypophosphorous acid (salt), thioglycolic acid, thioglycolic acid Octyl, thiopropionic acid, octyl thiopropionate, n-dodecyl mercaptan, t-dodecyl mercaptan, ethylene glycol dithioglycolate, ethylene glycol dithiopropionate, 1,4-butanediol thioglycolate, trimethylolpropane trithioglycol Rate, trimethylolpropane trithiopropionate, pentaerythritol tetrakisthioglycolate, pentaerythritol tetrakisthiopropionate, dipentaerythritol hexakisthioglycolate, dipentaerythritol hexakisthiopropionate Mercapto group-containing compounds, butanethiol, octanethiol, decanethiol, hexadecanethiol, octadecanethiol, cyclohexyl mercaptan, thiophenol, mercaptoethanol, thioglycerol, thiomalic acid, 2-mercaptoethanesulfonic acid and other mercaptan compounds, isopropanol, Secondary alcohols such as glycerin can be used.

  The polymerization initiator used in the polymerization reaction system when polymerizing the monomer in an aqueous solution includes persulfates and sulfites, persulfates and hydrogen peroxide, persulfates and hypophosphorous acid ( Salt) system, sulfite and oxygen system, polyvalent metal ions and one or more of these initiators (eg iron and hydrogen peroxide system, persulfate system, iron and persulfate and sulfite system), It can also be used in combination, such as a system comprising a reducing organic compound such as hydrogen peroxide and eliascorbic acid, thiouric acid, L-ascorbic acid and salts thereof. Of these, persulfates and sulfites, persulfates and hydrogen peroxide, persulfates and hypophosphorous acid (salts), polyvalent metal ions and persulfates and sulfites are preferred. More preferred are persulfate and hypophosphorous acid (salt) systems, polyvalent metal ions and persulfate and sulfite systems. Specific examples of the polyvalent metal ion include compounds exemplified by the heavy metal-containing compound. Of these, ammonium iron sulfate (Mole salt) is preferred.

  As described above, in the production method of the present invention, the polymerization initiator includes persulfate and sulfite, persulfate and hydrogen peroxide, persulfate and hypophosphorous acid (salt), and Although a polyvalent metal ion combined system is preferred, specific examples of persulfate include sodium persulfate (sodium peroxodisulfate), potassium persulfate, and ammonium persulfate.

  The amount of the persulfate added is preferably 0.5 to 5.0 g and more preferably 1.0 to 4.0 g with respect to 1 mol of the monomer. When the amount of persulfate added is 0.5 g or more, a water-soluble polymer having a sufficiently low molecular weight can be obtained, and when the amount added is 5.0 g or less, the purity of the resulting water-soluble polymer is reduced. The effect of persulfate that is sufficiently effective can be obtained without any problems.

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

  By using one or more persulfates and bisulfites in combination, a low molecular weight water-soluble polymer excellent in dispersibility and chelate ability can be obtained, which is preferable. By adding bisulfite to the initiator system in addition to persulfate, the resulting water-soluble polymer can be prevented from becoming too high in molecular weight, and the molecular weight of the polymer can be adjusted.

  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 obtained water-soluble 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. it can. In addition, the polymerization rate of the water-soluble polymer can be increased. For example, when producing polyacrylic acid and / or a salt thereof as the water-soluble polymer, 90% or more of acrylic acid and / or a salt thereof in 30 seconds. Can be converted to polyacrylic acid and / or its salts.

  Specific examples of the bisulfite include sodium bisulfite, potassium bisulfite, and ammonium bisulfite. Further, sulfite, pyrosulfite, etc. may be used instead of bisulfite.

The addition ratio of persulfate and bisulfite is 0.5 to 5 parts by mass, preferably 1 to 4 parts by mass, and more preferably 1.25 to 3 parts by mass with respect to 1 part by mass of persulfate. Within the range of parts by mass. By using 0.5 parts by mass or more of bisulfite with respect to 1 part by mass of persulfate, it is possible to obtain a sufficient effect of bisulfite and to keep the weight average molecular weight of the water-soluble polymer sufficiently low. it can. On the other hand, when the amount of bisulfite is 5 parts by mass or less with respect to 1 part by mass 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 degradation of the water-soluble polymer obtained and 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, which is preferable.
The addition ratio in the case of using a simple metal, a salt and / or a complex containing a metal having a plurality of oxidation numbers as a constituent component is preferably 20% by mass or less with respect to 100% by mass of persulfate. When it exceeds 20% by mass, the effect of promoting the reaction and the like is maintained, but there is a possibility that the economy is inferior. Further, 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 water-soluble polymer, there is a possibility that an undesirable result may be produced. More preferably, it is 0.2 mass% or less, More preferably, it is 0.02 mass% or less.

The addition amount of the persulfate and bisulfite as the polymerization initiator is preferably 0.5 to 20 g, more preferably the total amount of the persulfate and bisulfite as the polymerization initiator with respect to 1 mol of the monomer. Preferably it is 1-15g, More preferably, it is 1-12g, Most preferably, it is 1-8g. 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, it is possible to prevent deterioration of the performance of the obtained water-soluble polymer and precipitation of impurities during holding at a low temperature. When the addition amount of the above-mentioned polymerization initiator persulfate and bisulfite is within the range of 2 to 20 g, a polymer having a good molecular weight can be efficiently produced without adversely affecting the purity of the resulting water-soluble polymer. Obtainable.
The amount of addition 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 mass or less with respect to 100% by mass of the monomer. Is preferred. When it exceeds 1.5 mass%, the effect of promoting the reaction and the like is maintained, but there is a possibility that the economy is inferior. Further, 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 water-soluble polymer, there is a possibility that an undesirable result may be brought about. More preferably, it is 0.015 mass% or less, More preferably, it is 0.0015 mass% or less.

  Bisulfite may be dissolved in the aqueous solvent and added in the form of a bisulfite solution (preferably an aqueous solution). The concentration when used as the bisulfite solution (preferably an aqueous solution) is 10 to 40% by mass, preferably 20 to 40% by mass, and more preferably 30 to 40% by mass. 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 in terms of transportation and storage.

  In the present invention, as described above, it is also preferable to use a persulfate and hypophosphorous acid (salt) in combination as the 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.

  Examples of the hypophosphorous acid (salt) include hypophosphorous acid, sodium hypophosphite, potassium hypophosphite, and ammonium hypophosphite, and these may be hydrates.

  The amount of the hypophosphorous acid (salt) added is preferably 0.25 to 10 g, more preferably 0.5 to 6.0 g with respect to 1 mol of the monomer. When the amount of hypophosphorous acid (salt) added is 0.25 g or more, a water-soluble polymer having a sufficiently low polymerization average molecular weight can be obtained. Further, when the addition amount is 10 g or less, there is little adverse effect due to the remaining hypophosphorous acid (salt) and its residue, and a sufficiently effective hypophosphorous acid (salt) effect can be obtained.

  The addition ratio of the above hypophosphorous acid (salt) and persulfate is such that when the mass of hypophosphorous acid (salt) is 1 by mass, the mass of persulfate is 0.05-20. Is preferable, and it is more preferable that it is 1-10. When the mass ratio of the persulfate is 0.05 or more, the weight average molecular weight of the obtained water-soluble polymer can be suppressed sufficiently low, and when it is 20 or less, the persulfate addition effect can be sufficiently obtained.

  In the present invention, as described above, it is also preferable to use one or more persulfates and hydrogen peroxide in combination 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.

  The amount of hydrogen peroxide added is preferably 2.0 to 10.0 g, more preferably 3.0 to 8.0 g, with respect to 1 mol of the monomer. When the amount of hydrogen peroxide added is 2.0 g or more, a water-soluble 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 addition ratio of hydrogen peroxide and persulfate is preferably 0.1 to 5.0 persulfate when the weight of hydrogen peroxide is 1 by weight. More preferably, it is -3.0. When the weight ratio of persulfate is 0.1 or more, the weight average molecular weight of the obtained water-soluble polymer can be suppressed sufficiently low, and when it is 5.0 or less, the effect of adding persulfate can be sufficiently obtained. .

  In the present invention, the above combinations are particularly preferably used. However, as described above, other initiators (including chain transfer agents) may be appropriately used as necessary as long as the effects are not adversely affected. May be.

  The other initiator may be added in the form of an aqueous solution after being dissolved in the aqueous solvent. The concentration in the case of using as an aqueous solution may be 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.

  Since it is desirable that the heavy metal ion concentration of the water-soluble polymer obtained in the present invention is 0.05 to 10 ppm, it is desirable 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, particularly iron ions, as defined above is used in the material of the container or the like under the production conditions of the present invention. This is advantageous in terms of cost-effectiveness because it is eluted (supplied) in a reaction solution from SUS. In the production method of the present invention, when such a reaction apparatus such as a reaction vessel made of SUS or a stirring blade is used, the same operational effects as 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, a lot of heavy metal ions may be eluted. In such a case, since it is colored with heavy metal, an operation for removing such heavy metal ions is required, which is uneconomical. Moreover, there is no problem even if the reaction vessel is glass-lined or the like, and a heavy metal-containing compound may be used if necessary.

  In the production method of the present invention, the polymerization reaction of the monomer can be performed under any of acidic, neutral, and alkaline conditions depending on the initiator used.

  Examples of an alkali agent (also referred to as a pH adjuster or a neutralizer) for adjusting the pH of the reaction solution during the polymerization or neutralizing the monomer include sodium hydroxide and potassium hydroxide. Examples thereof include alkali metal hydroxides, alkaline earth metal hydroxides such as calcium hydroxide and magnesium hydroxide, and organic amine salts such as ammonia, monoethanolamine and triethanolamine. 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.

  In the polymerization, the above monomers, initiators and other additives are usually dissolved in a suitable solvent (preferably the same type of solvent as the reaction solvent) in advance and added to the reactor from a predetermined supply port. It is preferable.

  In the method for producing a water-soluble polymer according to the present invention, a neutralization degree (final neutralization degree) of the obtained water-soluble polymer can be appropriately determined by installing an alkali agent supply port in the discharge line. It can set to a predetermined range by adding an alkali component suitably.

  The final neutralization degree is not particularly limited because it varies depending on the intended use, but as described above, the neutralization degree during the polymerization of the acid group-containing monomer may be 50 mol% or more. Since it is preferable, it is preferable to set it to 50 mol% or more, for example, preferably 50 to 100 mol%, more preferably 70 to 99 mol%. Further, when the final neutralization degree exceeds 99 mol%, the polymer aqueous solution may be colored. Therefore, in applications where coloring is not preferred, the final neutralization degree is preferably set to 99 mol% or less.

[Water-soluble polymer composition]
As described above, the water-soluble polymer composition of the present invention is water-soluble by continuously supplying (i) a raw material containing a monomer having a polymerizable unsaturated bond to a reactor that essentially includes a stirrable tank. It is characterized by being produced by a continuous production method comprising a step of continuously producing a polymer and (ii) a step of taking out a part of the reaction liquid from the reaction apparatus. Usually, the number obtained by dividing the mass of the active ingredient in the obtained water-soluble polymer composition by the mass of the solid content is 0.9 or more. The upper limit of the number obtained by dividing the mass of the active ingredient of the obtained water-soluble polymer composition by the mass of the solid content is preferably 1.
The water-soluble polymer composition of the present invention is produced by the above-mentioned method, and is not particularly limited. However, from the viewpoint of production efficiency, those obtained without going through a purification step such as impurity removal are more preferable. . Further, after the polymerization step, the obtained polymerization composition is diluted with a small amount of water (about 1 to 400% by mass with respect to the obtained mixture) for the convenience of handling, etc., or concentrated and dried. The water-soluble polymer composition referred to in the present application is also included.
The water-soluble polymer composition of the present invention contains the water-soluble polymer of the present invention as an essential component. In addition, unreacted monomers, unreacted polymerization initiators, polymerization initiator decomposition products, impurities derived from raw materials, and the like may be included.

  The water-soluble polymer composition of the present invention may contain a solvent such as water in addition to the water-soluble polymer of the present invention (referred to as the water-soluble polymer polymer (water) solution of the present invention). ). In that case, content of a solvent can be set to 0-99 mass%, for example with respect to 100 mass% of water-soluble polymer compositions. The content of the solvent is preferably 60 to 99% by mass, more preferably 75 to 95% by mass, preferably 80 to 92% by mass, and 82 to 90% by mass with respect to 100% by mass of the water-soluble polymer composition. Most preferred.

  A preferred range of the active ingredient and solid content of the water-soluble polymer composition of the present invention is, for example, a range during polymerization, but the active ingredient is preferably 1 to 40%, and the solid content is 1 to 40% by mass. It is preferable that

[Use of water-soluble polymer and water-soluble polymer composition of the present invention]
The present invention is also a detergent, water treatment agent or dispersant containing the water-soluble polymer of the present invention and / or the water-soluble polymer produced by the production method of the present invention.
Moreover, the said cleaning composition means the additive for cleaning agents, a cleaning agent, the builder for detergents (detergent builder), and a detergent.

The detergent builder has an excellent ability to disperse dirt, and exhibits an action for preventing dirt from reattaching to clothes being washed.
As other composition components and blending ratios other than the water-soluble polymer in the detergent builder, various components that can be used in a normal detergent builder, and based on the blending ratio, the range does not impair the effects of the present invention. It can be used as appropriate.

The detergent may be a powder detergent or a liquid detergent. In addition to the water-soluble polymer, additives generally used in detergents can be used for the detergent. Examples of the additives include surfactants, alkali builders, chelate builders, anti-redeposition agents for preventing redeposition of contaminants such as sodium carboxymethylcellulose, and dirt inhibitors such as benzotriazole and ethylene-thiourea. , Soil release agent, anti-transfer agent, softener, alkaline substance for pH adjustment, fragrance, solubilizer, fluorescent agent, colorant, foaming agent, foam stabilizer, polish, bactericidal agent, bleaching agent, Bleaching aids, enzymes, dyes, solvents and the like are preferred. In the case of a powder detergent, it is preferable to blend zeolite.
When used in the above powder detergent, the water-soluble polymer is preferably added in an amount of 0.1 to 20% by mass, more preferably 0.2 to 10% by mass, and still more preferably 0 to 100% by mass of the detergent. .3 to 5% by mass, particularly preferably 0.4 to 4% by mass. If it is less than 0.1% by mass, the cleaning power of the detergent may be insufficient, and if it exceeds 20% by mass, it may be uneconomical.

The form of the water-soluble polymer in the detergent may be liquid or solid, and can be determined according to the form at the time of sale of the detergent (for example, liquid or solid). You may mix | blend with the form of the aqueous solution after superposition | polymerization, you may mix | blend in the state which reduced the water | moisture content of the aqueous solution to some extent, and may mix | blend in the state solidified dry.
The above detergents are used only for specific applications such as synthetic detergents for household detergents, textile industry and other industrial detergents, hard surface cleaners, bleach detergents that enhance the function of one of its components, and fiber auxiliaries. Also includes the detergent used.

  The surfactant is at least one selected from anionic surfactants, nonionic surfactants, cationic surfactants and amphoteric surfactants, and these surfactants include one or more. Can be used. When using 2 or more types, the combined use amount of the anionic surfactant and the nonionic surfactant is preferably 50% by mass or more with respect to 100% by mass of the total surfactant. More preferably, it is 60 mass% or more, More preferably, it is 70 mass% or more, Most preferably, it is 80 mass% or more.

Examples of the anionic surfactant include alkylbenzene sulfonate, alkyl ether sulfate, alkenyl ether sulfate, alkyl sulfate, alkenyl sulfate, α-olefin sulfonate, α-sulfo fatty acid or ester salt, alkane sulfonic acid. Salt, saturated fatty acid salt, unsaturated fatty acid salt, alkyl ether carboxylate, alkenyl ether carboxylate, amino acid type surfactant, N-acyl amino acid type surfactant, alkyl phosphate ester or salt thereof, alkenyl phosphate ester Or its salt etc. are suitable.
The alkyl group or alkenyl group in the anionic surfactant may have a branched alkyl group such as a methyl group.

Examples of the nonionic surfactant include polyoxyalkylene alkyl ether, polyoxyalkylene alkenyl ether, polyoxyethylene alkyl phenyl ether, higher fatty acid alkanolamide or its alkylene oxide adduct, sucrose fatty acid ester, alkyl glycoxide, fatty acid glycerin. Monoesters, alkylamine oxides and the like are preferred. The alkyl group or alkenyl group in the nonionic surfactant may have a branched alkyl group such as a methyl group.
As the cationic surfactant, a quaternary ammonium salt or the like is preferable.
As the amphoteric surfactant, a carboxyl type amphoteric surfactant, a sulfobetaine type amphoteric surfactant and the like are suitable.
The alkyl group and alkenyl group in the cationic surfactant and amphoteric surfactant may be branched from an alkyl group such as a methyl group.

  In general, the blending ratio of the surfactant is preferably 10 to 60% by mass with respect to 100% by mass of the liquid detergent. More preferably, they are 15 mass% or more and 50 mass% or less, More preferably, they are 20 mass% or more and 45 mass% or less, Especially preferably, they are 25 mass% or more and 40 mass% or less. If the blending ratio of the surfactant is less than 10% by mass, sufficient detergency may not be exhibited, and if it exceeds 60% by mass, the economy may be lowered.

  The blending ratio in the liquid detergent builder is usually preferably 0.1 to 20% by mass with respect to 100% by mass of the liquid detergent. More preferably, it is 0.2 mass% or more and 15 mass% or less, More preferably, it is 0.3 mass% or more, 10 mass% or less, More preferably, it is 0.4 mass% or more, 8 mass% Or less, and particularly preferably 0.5% by mass or more and 5% by mass or less. If the blending ratio of the builder for liquid detergent is less than 0.1% by mass, sufficient detergent performance may not be exhibited, and if it exceeds 20% by mass, the economy may be lowered.

  The water content contained in the liquid detergent is usually preferably 0.1 to 75% by mass with respect to 100% by mass of the liquid detergent. More preferably, it is 0.2 mass% or more and 70 mass% or less, More preferably, it is 0.5 mass% or more and 65 mass% or less, Especially preferably, it is 0.7 mass% or more, 60 mass% Or less, more preferably 1% by mass or more and 55% by mass or less, and most preferably 1.5% by mass or more and 50% by mass or less.

As the enzyme that can be blended in the detergent of the present invention, amylase, protease, lipase, cellulase and the like are suitable. Of these, alkaline amylase, protease, alkaline lipase, and alkaline cellulase, which are highly active in an alkaline washing solution, are preferred.
The amount of the enzyme added is preferably 5% by mass or less with respect to 100% by mass of the detergent. If it exceeds 5% by mass, improvement in detergency cannot be seen, and the economy may be reduced.

As the alkali builder, silicate, carbonate, sulfate and the like are preferable. As the chelate builder, diglycolic acid, oxycarboxylate, EDTA (ethylenediaminetetraacetic acid), DTPA (diethylenetriaminepentaacetic acid), citric acid and the like are preferable. A water-soluble polycarboxylic acid polymer may be used.
The above-mentioned detergent has excellent dispersibility, and can be a highly stable detergent with extremely high quality agent performance that is unlikely to cause deterioration in performance when stored for a long period of time or precipitation of impurities when held at a low temperature.

The said water treatment agent is added to water systems, such as a cooling water system and a boiler water system, for example. In this case, the water-soluble polymer may be added as it is, or one containing other components other than the water-soluble polymer may be added.
As other composition components and blending ratios other than the water-soluble polymer in the water treatment agent, various effects that can be used in normal water treatment agents and blending ratios thereof are not impaired. It can use suitably in the range.

<Pigment dispersant>
The water-soluble polymer or water-soluble polymer composition of the present invention can be used as a pigment dispersant.
Although the water-soluble polymer of the present invention can be used alone as a pigment dispersant, the pigment dispersant of the present invention may contain a condensed phosphoric acid as a solvent such as water or other compounding agents as necessary. And salts thereof, phosphonic acid and salts thereof, and polyvinyl alcohol.

The content of the water-soluble polymer of the present invention in the pigment dispersant is preferably 0.3 to 10% by weight with respect to the entire pigment dispersant. Further, any appropriate water-soluble polymer may be included as long as it does not affect the performance and effect.
According to the present invention, it is possible to provide a paper slurry having a low viscosity and a viscosity stability with time and having a high concentration. As a result, coating defects are suppressed when coating with the slurry, good base paper coverage, printing gloss, blister resistance, uniform printing surface feeling, and the inherent whiteness and poorness of the pigment are provided. It becomes possible to provide a coated paper for printing having significant points of transparency and ink acceptability.

  The pigment used in the present invention is not particularly limited, and examples thereof include kaolin, clay, heavy calcium carbonate, light calcium carbonate, titanium dioxide, satin white, talc, aluminum hydroxide, and plastic pigment.

  In the present invention, as a method for adjusting the pigment, conventionally known methods can be referred to or combined as appropriate, and examples thereof include a method in which primary dispersion is performed and wet pulverization is performed. This method is preferable in that a high-concentration pigment slurry having a low viscosity and excellent dispersion stability can be obtained. Of course, the method for adjusting the pigment according to the present invention is not limited to this wet pulverization method, and it is not limited at all to adopt an adjustment method without applying the wet pulverization treatment. In the method for preparing the pigment, the primary dispersion method is not particularly limited, but it is preferable to mix with a mixer, for example, a high-speed disper, a homomixer, a ball mill, a coreless mixer, a stirring disper, etc. It is preferable to use a high one.

  In the wet pulverization treatment, the water-soluble polymer of the present invention may be charged into a pulverizer and pulverized. In such a case, the polymer also serves as a grinding aid.

  The average particle size of the pigment contained in the slurry is preferably 1.5 μm or less, more preferably 1.0 μm or less. The average particle size referred to here is a particle size measured by a laser particle size distribution meter or a particle size distribution meter having an X-ray detector as used in Examples described later. The desired particle size is preferably 85% or more, more preferably 90% or more.

  When the pigment dispersant is used as a pigment dispersant, the amount of the pigment dispersant used is 0.1 to 5.0 parts by mass with respect to 100 parts by mass of the water-soluble polymer of the present invention. preferable. When the amount of the pigment dispersant used is within the above range, a sufficient dispersion effect can be obtained, and an effect commensurate with the addition amount can be obtained, which can be economically advantageous.

  The pigment slurry in the present invention preferably has a solid content concentration of 60% by mass or more, more preferably 70% by mass or more, and further preferably 75% by mass or more.

The viscosity of the pigment slurry is not particularly limited, but varies greatly depending on the slurry concentration. Therefore, when adjusted to 75% by mass, it is preferably 1000 mPa · s or less, more preferably 600 mPa · s or less. When it is higher than 1000 mPa · s, when the coating liquid prepared with the slurry as a main component is applied while receiving a high shearing force at high speed, coating defects such as streak, bleeding and sarcophagus are likely to occur. There is a possibility that an excellent coated paper texture cannot be obtained.
The pigment slurry viscosity is measured using a B-type viscometer. The value measured at 4, 60 rpm for 5 minutes.
Thus, the water-soluble polymer of the present invention is suitable for use in detergent builders, detergents, water treatment agents or dispersants, but also in other uses where the water-soluble polymer is used. Various properties exhibited by the polymer can be improved and used suitably.

The present invention will be described in more detail with reference to examples below, but the present invention is not limited to these examples. Unless otherwise specified, “part” means “part by mass” and “%” means “% by mass”.
Further, the weight average molecular weight, number average molecular weight, quantification of unreacted monomer, polymer composition, and solid content of the polymer aqueous solution of the polymer of the present invention were measured according to the following methods.

<Measurement conditions of weight average molecular weight and number average molecular weight (GPC)>
Measurement was performed by the method described above.

<Polymer composition, method for measuring solid content of polymer aqueous solution>
Measurement was performed by the method described above.

<Measurement of monomer in polymer composition>
The monomer was measured using liquid chromatography under the conditions shown in Table 1 below.
Measuring device: L-7000 series detector manufactured by Hitachi, Ltd .: UV detector L-7400 manufactured by Hitachi, Ltd.
Column: SHODEX RSpak DE-413 manufactured by Showa Denko Co., Ltd.
Temperature: 40.0 ° C
Eluent: 0.1% phosphoric acid aqueous solution Flow rate: 1.0 ml / min.

<Measurement of active ingredients>
Measurement was performed by the method described above.

<Heavy calcium carbonate grinding / dispersion test>
200 g of "heavy calcium carbonate" manufactured by Maruo Calcium Co., Ltd. Of the polymer to be evaluated while stirring at a low speed (about 300 rpm) in five stages, each having a stir bar (pin spacing 12 mm) arranged alternately so that the angle between adjacent pins is 90 °. Water was added so that 8.00 g of the aqueous solution (10% by mass in terms of solid content) and 77% of the calculated value of the slurry solid content were obtained. While further stirring, 500 g of alumina beads having a particle diameter of 2 mm were slowly added, and then time measurement was started and dispersed while maintaining a rotational speed of about 1400 rpm.
In 40 minutes from the start of pulverization, 4.00 g of the 10% by mass polymer aqueous solution described above was added, and 2.00 g was added in the same 70 minutes and 90 minutes, respectively. The pulverization was continued until the amount of 2 μm or less became 90% or more while measuring with LA-910) manufactured by HORIBA, Ltd.
The obtained slurry is put on a 1 mm sieve, and the slurry and beads are sieved, and then the slurry is put into a container (having a height and an inner diameter that can be measured later with a Brookfield viscometer, about 50 mL in volume). Collected. Immediately after the separation of the slurry and the beads was taken as a reference for time (after 0 hour).

<Measurement of viscosity over time>
The sample collected in the above <heavy calcium carbonate pulverization / dispersion test> was measured using a Brookfield viscometer (product number BM, manufactured by Tokimec Co., Ltd.) with spindle No. The sample was rotated for 5 minutes under the condition of 3, 60 rpm, and the values after 1 minute, 3 minutes and 5 minutes were read. Among these, the lowest indicated value was adopted as the viscosity (the slurry viscosity after 0 hour). The container after collecting the sample was placed in a 25 ° C. water bath until just before the measurement.

  In this measurement, the measurement after 7 days was required immediately after collecting the slurry, and the data after 1 hour and after 1 to 6 days were arbitrarily measured for confirming the viscosity change. The samples were stored in a constant temperature room at 25 ° C. except during the measurement.

<Example 1>
A pump and a Liebig cooler for extracting the reaction solution were prepared in a 2 L glass separable flask. A separable flask was charged with 720 g of water in advance and heated according to the recipe. Under the conditions, the reaction liquid extraction pump is started, and at the same time, the temperature in the flask is maintained at the set reaction temperature by air cooling as necessary, while keeping the predetermined reaction temperature constant, 37% by weight sodium acrylate (SA) aqueous solution, 15% by weight sodium persulfate (sodium peroxodisulfate; NaPS) aqueous solution, and 45% by weight sodium phosphinate (sodium hypophosphite; SHP as required) ) A prescribed amount of an aqueous solution and a 41 mass% sodium methacrylate (S-MAA) aqueous solution were added. The amount of the reaction liquid extracted from the reaction liquid extraction pump was adjusted so that the amount of the reaction liquid was kept constant. The polymerization prescription is as shown in Table 1, and the molecular weight was adjusted by adjusting the monomer, initiator, transfer agent, reaction temperature, and residence time.
The total mass of the added monomer, initiator, chain transfer agent and aqueous catalyst solution was determined by the residence time and the reaction time, but the reaction time was 6 hours. After the reaction, the raw material supply was stopped, the reaction liquid (water-soluble polymer composition 1) remaining in the flask was taken out after cooling, and a sample was prepared for measurement of physical properties and pulverization evaluation.
Table 2 shows the results of measuring the molecular weight of the polymer (practical polymer 1) in the water-soluble polymer composition 1, the active ingredient of the water-soluble polymer composition 1, and the solid content by the above-described methods.
Table 3 shows the results of heavy calcium carbonate pulverization / dispersion test and viscosity measurement over time by the above method.

<Examples 2-3>
In Example 1, except having changed superposition | polymerization prescription as shown in Table 1, it superposed | polymerized like Example 1 and obtained the water-soluble polymer compositions 2-3. Table 2 shows the results of measuring the molecular weight of the polymer (practical polymer) in the obtained water-soluble polymer composition, the active ingredient of the water-soluble polymer composition, and the solid content by the above method.
Table 3 shows the results of heavy calcium carbonate pulverization / dispersion test and viscosity measurement over time by the above method.

<Comparative Example 1>
A Liebig condenser was prepared in a 2 L glass separable flask, and 720 g of water was charged in advance in the separable flask and heated according to the prescription. Under the conditions, while adjusting the cooling water temperature and the cooling water amount so that the temperature in the flask maintains the set reaction temperature, 80% by mass acrylic acid (AA) aqueous solution, 15% by mass sodium persulfate ( A prescribed amount of an aqueous solution of sodium peroxodisulfate (NaPS) and an aqueous solution of 45% by mass sodium phosphinate (sodium hypophosphite; SHP) were added. The dropping time is 10-190 minutes for an AA aqueous solution, 10-195 minutes for an NaPS aqueous solution, 0-185 minutes for an SHP aqueous solution, and the formulation is as shown in Table 1.
After completion of the dropwise addition, the temperature is further maintained for 30 minutes, and after cooling, the solution is neutralized to pH 7 with a 48 mass% aqueous sodium hydroxide solution (comparative water-soluble polymer composition 1), and a sample is prepared for measurement of physical properties and evaluation of pulverization. went.
Table 2 shows the results of measuring the molecular weight of the polymer (comparative polymer 1) in the comparative water-soluble polymer composition 1, the active ingredient of the comparative water-soluble polymer composition 2, and the solid content by the above method.
Table 3 shows the results of heavy calcium carbonate pulverization / dispersion test and viscosity measurement over time by the above method.

<Comparative example 2>
Polymerization was performed in the same manner as in Example 1 except that 80% by weight AA aqueous solution was used instead of 37% by weight SA aqueous solution and 100% by weight methacrylic acid (MAA) was used in place of 41% by weight S-MAA aqueous solution. Carried out. After the reaction, the raw material supply was stopped, the reaction liquid remaining in the flask was cooled, neutralized to pH 7 with a 48% by mass aqueous sodium hydroxide solution (Comparative water-soluble polymer composition 2), and a sample was used for measurement of physical properties and evaluation of grinding. Prepared.
Table 2 shows the results of measuring the molecular weight of the polymer (comparative polymer 2) in the comparative water-soluble polymer composition 2, the active ingredient of the comparative water-soluble polymer composition 2, and the solid content by the above method.
Table 3 shows the results of heavy calcium carbonate pulverization / dispersion test and viscosity measurement over time by the above method.

<Examples 3 to 4>
In Comparative Example 2, polymerization was carried out in the same manner as in Comparative Example 2 except that the polymerization formulation was changed as shown in Table 1, and Comparative Water-soluble Polymer Compositions 3 to 4 were obtained. Table 2 shows the results of measuring the molecular weight of the polymer (comparative polymer) in the obtained comparative water-soluble polymer composition, the active ingredient of the comparative water-soluble polymer composition, and the solid content by the above method.
Table 3 shows the results of heavy calcium carbonate pulverization / dispersion test and viscosity measurement over time by the above method.

From the results shown in Table 3, it has been clarified that the polymer of the present invention has a good initial dispersive force and a dispersive force over time as compared with conventional polymers.

DESCRIPTION OF SYMBOLS 1 Tank 2 Piping which circulates outside the tank 3 Discharge line 4 Cooling machine 5 Motionless mixer 6 Circulation pump 7 Alkali agent supply port 8 Raw material supply port 9 Chain transfer agent supply port 10 Polymerization initiator supply port 11 Agent supply port 12 Discharge Pump a Circulation line inlet b Circulation line outlet

Claims (5)

(I) a step of performing polymerization by continuously supplying a raw material containing a monomer having a polymerizable unsaturated bond to a reactor containing a stirrable tank as an essential component;
(Ii) removing a part of the reaction liquid from the reaction apparatus;
A water-soluble polymer composition produced by a continuous production method having a mass obtained by dividing the mass of the active ingredient of the obtained water-soluble polymer composition by the mass of the solid content is 0.9 or more A water-soluble polymer composition characterized by the above. A pigment dispersant comprising the polymer composition according to claim 1. (I) a step of performing polymerization by continuously supplying a raw material containing a monomer having a polymerizable unsaturated bond to a reactor containing a stirrable tank as an essential component;
(Ii) removing a part of the reaction liquid from the reaction apparatus;
A continuous process for producing a water-soluble polymer having
A method for producing a water-soluble polymer, wherein the number obtained by dividing the mass of the active ingredient in the extracted reaction liquid by the mass of the solid content is 0.9 or more. The method for producing a water-soluble polymer according to claim 3, wherein the residence time of the reaction liquid in the tank is 240 minutes or less. The method for producing a water-soluble polymer according to claim 3 or 4, wherein the polymerization concentration in terms of acid type is 1 to 30% by mass.

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