JP2003119059A - Method of manufacturing cement additive and reaction apparatus used for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a powdery polycarboxylic acid-base cement additive of a high grade at a low cost for a short time by polymerizing and continuously disintegrating the polycarboxylic acid-base cement additive and a reaction apparatus used for the same. SOLUTION: The method of manufacturing the cement additive comprising continuously performing the operations from polymerization to disintegration by using the reaction apparatus equipped with a reactor having a lower bearing type agitator in manufacturing the cement additive by using a monomer essentially consisting of alkoxy polyalkylene glycol mono (meth) acrylate monomer and (meth) acrylic acid monomer, a chain-transfer agent and a polymerization initiator and the reaction apparatus equipped with the reactor having the lower bearing type agitator of a high torque type used for the same.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a cement additive and a reactor having a reactor having a lower bearing type agitator used for the method. More specifically, a method for producing a powdery polycarboxylic acid cement additive in a short time, high quality, and at low cost by polymerizing a polycarboxylic acid cement additive and continuously pulverizing the same, It has a method for producing a polycarboxylic acid cement additive in a short time, high quality, and at low cost by polymerizing a cement additive in bulk polymerization or at a high concentration close to bulk polymerization, and a high-torque lower bearing type agitator used therefor. The present invention relates to a reactor having a reactor.

[0002]

2. Description of the Related Art Conventionally, ligninsulfonic acid, naphthalenesulfonic acid, styrene-maleic acid resin, urea-formalin resin, etc. have been used as cement dispersants. However, there is a problem of environmental resistance due to its low biodegradability.

Polycarboxylic acid type cement additives have been developed as cement dispersants for solving the above problems.

For example, Japanese Patent Laid-Open No. 9-86990 discloses a polycarboxylic acid type cement additive excellent in slump retention performance and water reduction performance by controlling the molecular weight distribution of the polycarboxylic acid type cement additive within a specific range. Is disclosed.

Further, in this publication, as a particularly preferable method for producing a polycarboxylic acid type cement additive, a monomer mixture (I) containing an unsaturated carboxylic acid type monomer as an essential component is disclosed.
((Alkoxy) polyalkylene glycol (meth) acrylic acid ester-based monomer (a) 5 to 98% by weight (hereinafter referred to as%), (meth) acrylic acid or a salt thereof (b) 95 to 2% and with them) The amount of the copolymerizable monomer (c) 0 to 50%) is 10 to 28% with respect to the total amount of the raw materials used, and the neutralization rate of the monomer mixture (I) is 0 to 20. A method is described in which the monomer mixture (I) is added dropwise to a reaction vessel containing water under the condition of mol% and polymerization is performed at a temperature not higher than the cloud point of the monomer mixture (I).

Further, the above-mentioned production method is not particularly limited as long as a predetermined molecular weight distribution can be obtained, and a solution polymerization method using a polymerization initiator or a bulk polymerization method carried out at 50 to 200 ° C. (however, this method is used). Can employ a known polymerization method such as the above-mentioned method in which the monomer mixture (I) is added dropwise to a reaction vessel containing water), and it may be a batch type or a continuous type. ing.

Regarding the reaction vessel to be used, [Example] describes a glass reaction vessel equipped with a thermometer, a stirrer, a dropping funnel, a nitrogen introducing tube and a reflux condenser, and water is contained in the vessel. It is described that the reactor is a reactor in which an aqueous solution of the monomer mixture (I) can be added dropwise.

It should be noted that as the polymerization concentration in the above [Example], an example of 20 to 50% is described.

[0009] For example, Japanese Patent Laid-Open No. 2001-2734 discloses a cement additive which improves productivity while maintaining high water reducing performance or effectively lowers air entrainment and has excellent storage stability. Production method, that is, at least unsaturated polyalkylene glycol monomer (1)
And the unsaturated carboxylic acid-based monomer (2) during polymerization, the concentration of water in the reactor during the polymerization is set to 50% or less, and at least a part of the monomer to be polymerized is previously prepared. It is described that a polymer is produced by initially charging the reactor and charging the remaining monomer into the reactor after the initiation of the polymerization (note that, as a preferable concentration of water in the reactor during polymerization, 55-99%, preferably 60-95
%, Particularly preferably 65 to 90%, but it seems to be a typographical error).

Further, in the publication, a predetermined amount of the monomer mixture (a) or the monomer mixture (b) obtained by adding a chain transfer agent to the monomer mixture (a) in the reaction and the reaction vessel is described. If necessary, water is charged into the reactor, the temperature is raised to the polymerization temperature while substituting with nitrogen, and the remaining monomer mixture (a) or monomer mixture (b) (may be diluted with water) is added dropwise. Polymerization and aging are carried out. For example, in Example 1, an aqueous solution of the monomer mixture is placed in a glass reaction vessel equipped with a thermometer, a stirrer, a dropping funnel, a nitrogen introducing tube and a reflux condenser. A reaction vessel capable of dropping is used.

It should be noted that an example of about 70.8% was described as the polymerization concentration in Example 1 and an example of about 71.4 to 71.5% was described as the polymerization concentration in the remaining Examples 2-3. Has been done.

Even if the polymerization can be controlled on the flask scale, it is difficult to control the heat of polymerization and the molecular weight distribution in the same manner as on the flask scale when the scale is increased at a high concentration, and the invention has been completed on an industrial level. I can't say.

As described above, Japanese Unexamined Patent Publication Nos. 9-86990 and 2001-2734 describe both polycarboxylic acid type cement additives used as cement dispersants. Is manufactured and used as a liquid product diluted to about 20% and used.

However, it is manufactured in the form of an aqueous solution and has a content of 20%.
When sold and used as a liquid product diluted before and after, when it is opened and left in the summer, it usually rots in 1 to 2 weeks. Further, in the winter and cold regions, it is necessary to freeze and separate and heat it for paying out. When heated, it may deteriorate and may not be redissolved. In this case, it must be discarded.

As a method for solving the problems of the products produced in the form of an aqueous solution and sold and sold as a liquid product diluted to about 20%, a polymer produced in the form of an aqueous solution is concentrated differently from the polymerization step. There is also a method of transferring to a dryness process to obtain a mixture of powder and solid, crushing this into a product with good storability, and re-dissolving it in water at the time of use to prepare a liquid product. It is not only costly but also extremely hygroscopic to re-dissolve the polymerization liquid obtained at the concentration in a separate step by concentration to dryness, pulverize it with a pulverizer, and re-dissolve it in water when using it. Is large, it is easy to be left in a mess, and it is difficult to dissolve it uniformly.

When a concentrated dry solid product of a polycarboxylic acid cement additive is crushed by a crusher, the polycarboxylic acid cement additive has poor crystallinity, so that crushing heat or shearing heat is generated by crushing. It becomes rubbery and cannot be crushed.

This problem can be solved by blowing cold air into the crusher and cooling the crusher to an extremely low temperature. However, even if the crusher can be crushed, it is possible to obtain amorphous fine particles having a spherical shape. Can't get Amorphous fine particles have a large hygroscopic property and cause problems such as blocking, and difficulty in uniform dispersion when water is added by premixing with cement. Furthermore, when the polymerization liquid is pulverized by a spray dryer, even if it can be granulated into a certain shape, it must be diluted to a viscosity of about 20% that can be sprayed, and the cost of spray drying becomes high. Moreover, the obtained particles are liable to become hollow, have extremely high hygroscopicity, and cause a problem that is the same as that of the amorphous powder.

Therefore, the products currently on the market and occupying the market are liquid products diluted to around 20%. Amorphous powder products that are slightly crushed by the above-mentioned crusher are also sold, but the cost is high and it has not been possible to replace liquid products.

Due to the above reasons, lignin, which has been used for many years, has a problem of environmental resistance due to its small biodegradability, and is far inferior in performance to polycarboxylic acid cement additives (water reducing agents). Sulfonic acid, naphthalene sulfonic acid, styrene maleic acid resin, urea formalin resin and the like are still used, and polycarboxylic acid cement additives have not been actively used in place of these.

Other factors that increase the cost of the polycarboxylic acid type cement additive are long polymerization time, low equipment efficiency (productivity), high transportation cost, and high storage cost. These include the loss of residual adherence to the container and the large cost of container disposal.

[0021] For example, in Japanese Patent Laid-Open No. 2001-2734, a small amount of a monomer is charged in advance in a reaction vessel, and after the initiation of polymerization, the remaining monomer is added and the internal temperature is maintained so that the maximum monomer concentration is 99%. Is described.

However, as a result of the study by the present inventors, Japanese Patent Laid-Open No.
When polymerization is performed in a polymerization system having a monomer concentration of 75% or more using the apparatus described in Japanese Patent Publication No. 001-2734, bench scale, further industrial scale, that is, 30 L or more, further 1000 L or more of a suspended type or kneader type reactor However, it is difficult to uniformly mix the polymerization initiator and the monomer. It usually takes 10 to 30 minutes to uniformly mix the monomers having different viscosities and polarities, the generated polymer and the monomers, and the polymerization initiator and the chain transfer agent. Difficult and only polymerization in a heterogeneous system occurs, the molecular weight distribution is narrow, good quality products cannot be obtained, and in many cases gelation occurs, so good products cannot be produced. Also, a small amount of monomer is charged in advance in the reaction vessel, and after the start of polymerization, the remaining monomer is added to maintain the internal temperature, so the monomer concentration gradually decreases from the start to the end of the polymerization, and only products with a wide molecular weight distribution range I can't get it. Close to bulk polymerization 75
%, The initial concentration of the polymerization initiator is high, but it gradually decreases as described above (when adding the polymerization initiator to the monomer, when the polymerization is performed at a higher concentration than when the polymerization is performed at a low concentration). In this case, the concentration of the polymerization initiator in the entire polymerization system becomes higher), and the molecular weight distribution width becomes wider. In addition, there is a large difference in viscosity between the monomer and polymer, but since a reactor that strongly and rapidly kneads and mixes is not used, heterogeneous polymerization occurs, and cross-linking or branching reactions, and even gelled products that do not dissolve in water, are included. However, only polymers can be obtained.

Instead of the apparatus described in Japanese Patent Laid-Open No. 2001-2734, a reactor such as a suspension type reactor or a suspension type screw reactor which is capable of kneading and mixing strongly and rapidly is used to obtain a polymerization system having a high monomer concentration. The same applies to polymerization.

Furthermore, no technique has been proposed for immediately neutralizing and powdering after polymerization.

Not only the suspension type reactor and the horizontal type reactor but also the paddle type reactor, the ribbon blender type reactor, and the kneader type reactor can be used to cope with an extremely large torque applied when powdering a highly viscous material. Can not. Even when using a kneader type reactor that can withstand high torque among the reactors, the molecule is cut due to high shear that occurs at the contact point between the bottom surface and the blade, and a crosslinked gelled product due to shear radicals is produced to obtain a good product. I can't.

When the polymerization of the polycarboxylic acid type cement additive is made to have a high concentration to approach the bulk polymerization, in a usual suspension type reactor or a high viscosity polymerization reactor having an upper bearing type screw blade, a uniform monomer distribution is obtained. Kneading, uniform contact with the polymerization initiator, dissolution, the polymerization is initiated 1
It is impossible to do it within 2 minutes. In order to make uniform contact and compatibility between the monomer and the polymerization initiator in a short time, the only way to increase the polymerization temperature is to raise the polymerization temperature. However, if the polymerization temperature is increased, the methoxypolyethylene glycol (meth) acrylate may be hydrolyzed. It is the main cause. To avoid this, add water to lower the monomer concentration (polymerization concentration),
A method is employed in which the polymerization temperature is lowered and the polymerization is carried out at a concentration and temperature at which hydrolysis or di (meth) acrylate is not formed.

According to the description in Japanese Patent Laid-Open No. 2001-2734, when it is attempted to polymerize at a high concentration of, for example, 75% or more, particularly in the vicinity of bulk polymerization, even if a suspended reactor is used, an extremely high viscoelastic region is obtained. It is impossible to uniformly knead and react, and normal polymerization does not occur. Further, it cannot be uniformly neutralized, and when it is attempted to be neutralized, it rapidly agglomerates.

Incidentally, there is a kneader type reactor as the only reactor capable of pulverization, but when this is used, high speed rotation is not possible and the mixing efficiency is extremely poor for structural reasons. It takes a very long time to be added and uniformly dissolved in the whole, and the larger the scale, the longer the time, and the uniform polymerization is not performed. In addition, strong shear friction occurs at the contact point between the bottom surface and the blade, cross-linking by molecular cutting radicals, low molecular weight of partially depolymerized polymer and alkoxy polyalkylene glycol group hydrolyzed, and low viscosity component increase, A large amount of deposits are generated on the blades and walls. further,
At the time of discharge, the deposits fall off and are mixed in as a non-dehydrated lump from a fist size to a golf ball size, and when crushed by a crusher, normal temperature crushing becomes impossible. In addition, since a large amount of deposits remain and remain during the next reaction, not only the molecular weight distribution widens, but also the remaining deposits (polymer) act as a polymerization initiator to form polymer radicals and gel. It becomes easy and it becomes difficult to obtain high quality powder.

On the other hand, the monomer concentration (polymerization concentration) is 75%.
If it is less than 1, the polymerization time increases as the concentration decreases. For example, polymerization at 75% for about 2 hours becomes 1 at 40%.
It takes 5 hours. If the polymerization temperature is increased or the amount of the catalyst added is increased in order to shorten the polymerization time, the molecular weight distribution becomes broad and only those containing a crosslinked polymer can be obtained.

[0030]

The present invention has been made to solve the above-mentioned problems, and has a reactor having a high-shear kneading function and a high-torque lower bearing type agitator (for example, (( Yes) Sanso Micron, Tokuhei 5-12
Japanese Patent Application No. 200, which is an improvement of the stirring tank described in Japanese Patent No. 372.
By using the reactor described in FIGS. 1, 2 and 3 which is a further improvement of the reactor described in the specification of 0-182993, the polycarboxylic acid cement additive is continuously polymerized to powdered. In addition, using a reactor having the above-mentioned high shear kneading function and a high torque lower bearing type agitator, the monomer concentration of the raw material of the polycarboxylic acid cement additive is 75%.
As mentioned above, it is possible to polymerize at a high concentration, preferably in the form of lumps, and further to find a reactor having the high shear kneading function used in the above method and having a high torque lower bearing type agitator, and to complete the present invention. Only

That is, the present invention provides (1) a monomer containing an alkoxypolyalkylene glycol mono (meth) acrylic acid ester monomer and a (meth) acrylic acid-based monomer as main components, a chain transfer agent, and a polymerization initiator. When a cement additive is produced using, a method for producing a cement additive characterized in that a reaction device having a reactor having a lower bearing type stirrer is used to continuously perform from polymerization to pulverization (claim 1 ), (2) the chain transfer agent is a water-soluble chain transfer agent and / or a water-insoluble chain transfer agent, and the polymerization initiator is a polymerization initiator aqueous solution, a polymerization initiator organic solvent solution or a polymerization initiator Claim 1 as it is
(3) The peripheral speed of the impeller of the stirrer is set to 9 in order to instantaneously and uniformly contact-dissolve (compatibilize) or disperse the monomer, the chain transfer agent and the polymerization initiator.
The method according to claim 1 or 2, wherein the polymerization is carried out batchwise in a range of 0 to 600 m / min (claim 3), and (4) intermittently or continuously the monomer and chain transfer to a reactor having a lower bearing type agitator. Supply agent and polymerization initiator,
The production method according to claim 1, 2 or 3 (claim 4), wherein the initial polymerization is carried out for 5 to 30 minutes and the aging polymerization is carried out for 20 minutes or more. (5) The initial polymerization time is 10 to 30 minutes. (Claim 5), (6) The method according to claim 1, 2, 3, 4 or 5, wherein the monomer concentration is 75% or more (Claim 6), (7) The monomer concentration is bulk polymerization or bulk The method according to claim 1, 2, 3, 4 or 5 (claim 7), (8), which has a concentration close to that of polymerization (concentration with or without addition of water or an organic solvent so that the monomer melts at the polymerization temperature). ) The polymerization temperature is 60 to 93 ° C.
The manufacturing method according to 2, 3, 4, 5, 6 or 7 (claim 8),
(9) The polymerization temperature is 65 to 90 ° C.
The manufacturing method according to 3, 4, 5, 6 or 7 (claim 9), (1
0) Polymerization pressure is 0.098 (normal pressure) to 0.196 MPa
The range of (1 kg / cm ² · G) is 1, 2, 3,
The manufacturing method according to claim 4, 5, 6, 7, 8 or 9 (claim 1
0), (11) The neutralizing agent used for neutralization after completion of the polymerization is a powder of an alkaline earth metal hydroxide or an alkali metal carbonate, 1, 2, 3, 4, 5, 6, 7, The manufacturing method (claim 11) according to claim 8, 9 or 10, and (12) before adding the neutralizing agent, dehydrating under reduced pressure to a moisture content of 3% or less and adding the neutralizing agent. 5, 6, 7, 8, 9, 10 or 11 (claim 12), (13) At the time of neutralization, 20% or less of a poor solvent is added to the total weight to make it non-uniform and powder. And volatile components are distilled off under reduced pressure.
2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or 1
The method according to claim 2 (claim 13), (14) at the time of neutralization, 10% or less of a poor solvent is added to the total weight to make the mixture non-uniform and pulverize, and the volatile components are distilled off under reduced pressure. 2, 3,
Production method (claim 14) according to 4, 5, 6, 7, 8, 9, 10, 11 or 12, (15) From the stage where the neutralizing agent is uniformly dispersed, the peripheral speed of the blade of the stirrer is gradually increased. Finally, by decompressing and drying to 90 m / min or less so as to keep the internal temperature at 90 ° C or less, alteration of powder due to heat generation by shearing (generation of gelation product by molecular cutting radicals)
Claims 1, 2, 3, 4, 5, 6, 7, 8, which prevent
The manufacturing method according to 9, 10, 11, 12, 13 or 14 (claim 15), (16) an alkoxypolyalkylene glycol mono (meth) acrylic acid ester monomer and a (meth) acrylic acid-based monomer as main components When a cement additive is produced by using a monomer, a chain transfer agent and a polymerization initiator, the reaction apparatus having a reactor having a lower bearing type agitator is used to polymerize at a monomer concentration of 80% or more. Manufacturing method of cement additive (Claim 1)
6), (17) The method for producing a cement additive according to claim 16, wherein the concentration of the monomer to be polymerized is 90% or more (claim 1
7), (18) After completion of the polymerization, water is added to dilute until the viscosity is such that it can be filled and taken out in a drum, a lorry or a can, and alkali metal carbonate, alkaline earth metal hydroxide, alkali metal hydroxide, 18. The method according to claim 16 or 17, wherein the method is neutralized with ammonia or amine (claim 18),
(19) Claims 1, 2, 3, 4, 5, 6, 7, 8, 9,
A reactor having a lower-bearing stirrer used in the method for producing the cement additive according to 10, 11, 12, 13, 14, 15, 16, 17, or 18, which is a reactor having a lower-bearing stirrer, It has a monomer tank, a polymerization initiator tank, a condenser and a condenser condensate holder, so that the monomer tank and the polymerization initiator tank can feed the monomer and the polymerization initiator through a weighing machine into a reactor having a lower bearing type agitator. Is connected to a reactor having a lower-bearing stirrer, and a condenser is connected to a reactor having a lower-bearing stirrer so that volatiles from the reactor having a lower-bearing stirrer can be cooled, condensed, and refluxed. The valve switching allows cooling and condensation from the condenser. The lower bearing is characterized in that it is connected to the condenser condensate holder so that it can be collected, a pressure control valve is provided in the exhaust line, and it can be controlled to normal pressure, pressurization, or decompression by switching the valve. A reactor having a reactor having a mold stirrer (claim 1
9), (20) Claims 1, 2, 3, 4, 5, 6, 7,
8, 9, 10, 11, 12, 13, 14, 15, 16,
A reactor having a reactor having a lower-bearing stirrer used in the method for producing the cement additive according to 17 or 18, which is a reactor for initial polymerization having a lower-bearing stirrer, a reactor for aging polymerization having a lower-bearing stirrer, It has a monomer tank, a polymerization initiator tank, a condenser and a condenser condensate holder, so that the monomer tank and the polymerization initiator tank can supply the monomer and the polymerization initiator to an initial polymerization reactor having a lower bearing type agitator. Is connected to an initial polymerization reactor having a lower bearing type agitator, and the initial polymerization reactor having a lower bearing type agitator is a lower bearing type initial polymerization product obtained by the initial polymerization reactor having a lower bearing type agitator. Feeding to a reactor for aging polymerization with stirrer It is connected to cut the initial polymerization, aging both for the polymerization condenser is cooled and condensed and the volatiles from the reactor having a lower bearing stirrers
It is connected to a reactor with a lower bearing type stirrer so that it can recirculate, and it is connected to a condenser so that cooling / condensate from the condenser accumulates in the condenser condensate holder for both initial polymerization and aging polymerization by switching valves. A reactor having a lower bearing type stirrer characterized in that a pressure control valve is provided in an exhaust line and can be controlled to normal pressure, pressurization, and depressurization by switching valves (claim Item 2
0), (21) A stirrer for a reactor having a lower bearing type stirrer has horizontal blades that are almost in contact with the bottom surface, rising blades that are present at both ends of the horizontal blades and are almost in contact with the wall surface, and the middle of the reactor (the middle of the top surface and the bottom surface) The horizontal blades and the falling blades existing in the horizontal blades, and the horizontal blades that are almost in contact with the bottom surface are knife blades to scrape up the substances that adhere to and deposit on the bottom surface. The rising blade that is in contact with the wall surface is a knife blade that scrapes off the substance that adheres to the side surface, and the horizontal blade that exists in the middle of the reactor presses the substance at the bottom. 21. The reactor according to claim 19 or 20, wherein the blades descending from the intermediate horizontal blades are configured to crush agglomerates (claim 21), and (2).
2) The reaction device (claim 22) according to claim 21, wherein each of the knife edges is processed into a comb shape.

[0032]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, an alkoxypolyalkylene glycol mono (meth) acrylic acid ester monomer and a monomer containing a (meth) acrylic acid monomer as a main component, a chain transfer agent and a polymerization initiator Is used to produce cement additives.

The cement additive is used as an AE water reducing agent which improves the fluidity of the cement and enables the cement to be constructed with a low water content.

The above-mentioned alkoxy polyalkylene glycol mono (meth) acrylic acid ester monomer and (meth)
The monomer containing an acrylic acid-based monomer as a main component means that the concentration of the alkoxypolyalkylene glycol mono (meth) acrylic acid ester monomer and the (meth) acrylic acid-based monomer with respect to all the monomers is 80% or more, and Is 90%
These are the above monomers.

The above-mentioned alkoxy polyalkylene glycol mono (meth) acrylic acid ester monomer is hydrophilic to the particles of cement or sand and therefore has electrostatic affinity and repels electrostatically. The steric repulsion by the glycol (PAG) chain acts synergistically, and is a component used for increasing the fluidity by using a small amount of water. In addition, (meth) acrylic acid-based monomers other than the alkoxypolyalkylene glycol mono (meth) acrylic acid ester monomers are used to have an ionic and electrostatic affinity with the surface of cement or sand. It is the ingredient used.

Specific examples of the alkoxy polyalkylene glycol mono (meth) acrylic acid ester monomer include, for example, a number average molecular weight of 500 to 2000, further 80 in view of the relationship between esterification reactivity and performance.
Examples thereof include esters of 0-1200 alkoxy polyalkylene glycol and (meth) acrylic acid.

If the number average molecular weight of the alkoxypolyalkylene glycol is too small, the esterification reactivity is high, but the performance tends to be poor. If it is too large, the esterification reactivity is poor and the cost is high. Tends to become.

Examples of the alkoxy polyalkylene glycol include methoxy polyethylene glycol,
Ethoxy polyethylene glycol, methoxy polypropylene glycol, ethoxy polypropylene glycol,
Examples thereof include methoxy glycol and ethoxy glycol obtained by copolymerizing ethylene oxide and propylene oxide, but are not limited thereto. Of these, methoxypolyethylene glycol is preferable from the viewpoint of hydrophilicity, steric electrostatic repulsion and cost.

The alkoxypolyalkylene glycol mono (meth) acrylic acid ester monomers may be used alone or in combination of two or more.

Examples of the (meth) acrylic acid type monomer include (meth) acrylic acid and (meth) acrylic acid salts (salts of alkali metals, ammonia, amines, etc.) and the like. These may be used alone or in combination of two or more. Of these, methacrylic acid is preferable in terms of price, performance, and polymerizability.

The above-mentioned alkoxy polyalkylene glycol mono (meth) acrylic acid ester monomer and (meth)
The ratio of the alkoxy polyalkylene glycol mono (meth) acrylic acid ester monomer to the total amount of the acrylic acid-based monomer is generally 68 to 98%, more preferably 73 to 9%.
It is preferably 3%, particularly 78 to 88%, from the viewpoint of product price and mortar flow performance of cement.

As the monomer used in addition to the above main component, for example, (meth) acrylic acid ester such as glycerin (meth) acrylate and short chain alcohol (meth) acrylate is alkoxypolyalkylene glycol mono (meth) acrylic acid ester. Used as an alternative to monomers, vinyl monomers such as vinyl acetate and polyunsaturated carboxylic acids such as maleic acid and fumaric acid are used (meth).
Used as an alternative to acrylic acid monomers. The amounts used as alternatives are preferably below 20% of each.

The above-mentioned alkoxy polyalkylene glycol mono (meth) acrylic acid ester monomer and (meth)
It is preferable that the concentration of the monomer mainly containing the acrylic acid-based monomer is 75% or more, more preferably 80% or more, and especially 85% or more with respect to the total reaction system. The concentration is 75%
As described above, when the reactor having the lower bearing type agitator is used, the polymerization rate is high, the productivity is excellent, and the deterioration of quality such as hydrolysis and gelation is reduced. Moreover, it becomes easy to manufacture a spherical powdered product.

The chain transfer agent may have a weight average molecular weight of 5,000 to a molecular weight of a polymer produced from the monomer.
It is used as a main control factor to reach 200,000 and even 10,000 to 100,000.

As the chain transfer agent, a water-soluble chain transfer agent and / or a water-insoluble chain transfer agent can be used. When using the water-soluble chain transfer agent,
When the monomer concentration is 75 to 95%, it is preferable from the viewpoint that uniform polymerization can be controlled, and when the water-insoluble chain transfer agent is used, when the monomer concentration is 95% or more, uniform polymerization is achieved. It is preferable because polymerization can be controlled.

The molecular weight at the time of polymerization is controlled by the polymerization temperature,
It is carried out at a monomer concentration, a polymerization initiator concentration, and a chain transfer agent concentration.

Specific examples of the water-soluble chain transfer agent include:
For example, thiols such as mercaptoethanol, thioglycolic acid, acid compounds such as mercaptopropionic acid, thioglycols such as thioglycol, sodium methallyl sulfonate, sodium allyl sulfonate, etc.,
Specific examples of the water-insoluble chain transfer agent include α
Examples thereof include, but are not limited to, styrene dimers such as methylstyrene dimer, a mixture of α-methylstyrene monomer and α-methylstyrene dimer, and α-methylstyrene monomer alone.
These may be used alone or in combination of two or more. Among these, thiols such as mercaptoethanol and acid compounds such as thioglycolic acid and mercaptopropionic acid are preferable from the viewpoints of cost and ease of polymerization control.

Since the thiols, thioglycolic acid, mercaptopropionic acid and thioglycols are added to the polymerization system of the present invention in a small amount, they are compatible with non-aqueous systems and may be used in non-aqueous systems. it can.

The amount of the chain transfer agent used is usually
The amount is preferably 0.05 to 2.0 parts, more preferably 0.1 to 1.5 parts, relative to 100 parts by weight of the monomer (hereinafter referred to as "parts").

As the polymerization initiator, an oil-soluble polymerization initiator, a water-soluble polymerization initiator or the like can be used without particular limitation.

When the above-mentioned polymerization initiator is used, an aqueous solution of a water-soluble polymerization initiator, an organic solvent solution of an oil-soluble polymerization initiator or the polymerization initiator itself is used, but an aqueous solution of a water-soluble polymerization initiator is used. If the monomer concentration is 75-9
When it is in the range of 5%, a uniform polymerization reaction easily occurs, and when an organic solvent solution of an oil-soluble polymerization initiator is used, when a monomer concentration is 95% or more, a uniform polymerization reaction easily occurs. It is preferable to use the polymerization initiator itself, because treatment of distilled water becomes easy.

When the polymerization initiator is used as an aqueous solution or an organic solvent solution, it is preferable that the solution has a saturated solubility. As the organic solvent, for example, alcohol, ketone, xylene, etc. are used.

Specific examples of the oil-soluble polymerization initiator include:
For example, hydroperoxide such as cumene hydroperoxide, peroxide such as benzoyl peroxide, azo compound such as azobisbutyronitrile, and the like, specific examples of the water-soluble polymerization initiator include, for example, ammonium persulfate, Examples include persulfates such as potassium persulfate and hydrogen peroxide. These may be used alone or in combination of two or more. Among these, azobisbutyronitrile is preferable as the oil-soluble polymerization initiator, and ammonium persulfate and hydrogen peroxide are preferable as the water-soluble polymerization initiator, from the viewpoints of safety and controllability.

The amount of the polymerization initiator used is usually
The amount is preferably 0.05 to 2.0 parts, more preferably 0.1 to 1.5 parts, relative to 100 parts of the monomer.

In the present invention, a reactor having a lower bearing type agitator is used when a cement additive is produced using the above-mentioned monomer, chain transfer agent and polymerization initiator.

The reactor having the lower bearing type agitator means a bearing with a shaft having a bearing portion provided on the bottom surface of the reactor, an agitation blade attached to the shaft (the above is an agitator), and a blade for rotating the blade. It is a reactor that has a motor and can stir the contents by an attached stirrer.

Since the reactor has a stirrer attached to the lower bearing and the contents are agitated by the stirrer attached to the lower bearing, the alkoxypolyalkylene glycol mono (meth) acrylic acid ester mono-monomer, which is the main monomer, is conventionally used. When an alkoxypolyalkylene glycol part having a large molecular weight of about 1000 is used as a body and other monomers, a chain transfer agent, and water are pre-mixed to be uniform, they have greatly different properties (viscosity and compatibility). It was impossible to make it uniform in a short time because of 75%
As described above, even at a concentration of 80% or more up to the bulk polymerization, homogeneous compatibilization or dispersion can be carried out instantly (between 1 and 2 minutes when the polymerization is started), so that uniform polymerization can be performed. it can. As an extreme example, for example, the number c
P monomer, tens of thousands of cP monomer or polymer, powder monomer or powder polymerization initiator,
It can be instantly homogenized or dispersed. By the way, it can be made uniform in about 10 seconds or less at a concentration of 75 to 85%, about 20 seconds or less at 90%, about 30 seconds or less at 95%, and about 50 seconds at 100%. In addition, for the time when it became uniform, samples were sampled at three points with the passage of time (stop stirring every 10 seconds, sample at three points along the circumference of the reactor, and cool with ice. Stop stirring. (Do not add to the time from the start to the start), measure the peroxide value of the contained peroxide, and make it uniform time, that is, the three-point peroxide value is ± 5% or less of the average value. It is the time obtained by measuring the time. However, the added peroxide is 10
It was set to 0%, and if not, converted.

The above-mentioned monomer, chain transfer agent and polymerization initiator are intermittently or continuously supplied to a reactor having a lower bearing type stirrer, and these are instantaneously and uniformly subjected to catalytic dissolution (compatibility). As the stirring conditions, the peripheral speed of the blade of the stirrer is 90 to 600 m / min, and further 100
It is preferable to carry out batchwise continuous polymerization at ˜500 m / min, especially 120 to 400 m / min, especially 150 to 300 m / min.

The continuous method in the batch continuous method means that a series of steps from polymerization to pulverization (in the case of producing a liquid product, production) is continuously performed, and the batch method will be described later, for example. When the initial polymerization reaction, the aging polymerization reaction and the pulverization are continuously carried out in one reactor as shown in FIG. 1, the aging polymerization reaction is carried out after the initial polymerization of the monomer, followed by the neutralization and the pulverization. Therefore, each of the steps is performed separately, but each of these steps is performed separately, as will be described later with reference to FIG.
In the case of carrying out polymerization to pulverization using two reactors, as shown in, the first reactor (usually,
The initial polymerization of the monomer is continuously carried out with a small volume, and the resulting prepolymer is continuously supplied to the second reactor (usually,
Large capacity), and when the second reactor reaches a predetermined amount, pulverization is performed, and this pulverization will be performed in each step. It means to do. When powdered in the second reactor, two or more second reactors are provided in order to continuously transfer the prepolymerized product from the first reactor. Powder in the second reactor,
The remaining second reactor may continuously receive prepolymer from the first reactor. Also in this case, the step of pulverization is carried out batchwise while continuously performing from initial polymerization to pulverization.

In the case of, the initial polymerization is continuous, and the aging polymerization and the following are batchwise, and this case is also included in the batch continuous system.

When a conventional reactor such as an ordinary suspension type reactor, paddle type reactor, ribbon blender type reactor or kneader type reactor is used, the rotation speed is small and the stirring efficiency is low, so that the monomer mixture and the polymerization initiator are homogeneous. It takes 10 to 20 minutes to dissolve in water. When the monomer mixture is charged into the reactor and the polymerization initiator aqueous solution is added at the same time or afterwards, or when the monomer mixture or the polymerization initiator is added to the polymerized polymer, it is necessary to ensure a uniform compatibilization time of 20 minutes or more. Is. Therefore, heterogeneous polymerization occurs, and (meta)
Acrylic acid type monomer and alkoxy alkylene glycol (meth) acrylic acid ester monomer may be polymerized independently, or uneven polymerization between pre-polymerized polymer and additional monomer may occur. As a result, the molecular weight distribution becomes broader due to non-uniformity. Further, the polymerization initiator is deactivated during the long-term polymerization, and the unreacted monomer cannot be completely converted into the polymer. When a polymerization initiator is added and the mixture is aged and polymerized, a large amount of radicals act on the produced polymer to cause cross-linking and branch polymerization, and a gelled product is produced. Therefore, when a conventional suspended reactor or horizontal reactor is used, it is difficult to obtain a non-defective product which is uniform and has a narrow molecular weight distribution and a small amount of branched polymer or gelled product by polymerization with a monomer concentration of 75% or more. There are no literatures that demonstrate examples or suggest possibilities. Further, in the case of polymerization with a monomer concentration of less than 75%, it takes 2 hours or more for polymerization, and it takes 2 hours or more for condensing water to neutralize and powder, so that powder is pulverized through a high torque and high viscoelastic region. Is impossible.

In the present invention, the monomer concentration is preferably 75.
% Or more, more preferably 80% or more, and especially 90% or more, particularly at a bulk polymerization or a concentration close to the bulk polymerization (concentration with or without addition of water or an organic solvent so that the monomer melts at the polymerization temperature), Using a chain transfer agent and a polymerization initiator, these are instantly and uniformly contact-dissolved (compatibility),
In order to polymerize, the peripheral speed of the blade of the stirrer is 90 to 600 m / min, and further 100 to 500 m / min as described above.
Min, especially 120-400 m / min, especially 150-
The polymerization temperature is 60 to 93 ° C., further 65 to 90 ° C., and the polymerization pressure is 0.098 (normal pressure) to 0.
For example, by batchwise continuous polymerization in the range of 196 MPa (1 kg / cm ² · G), the polymerization time at the initial polymerization is 5 to 30 minutes, further 10 to 30 minutes, and especially 10 minutes.
~ 25 minutes, then 20 minutes or more as the aging polymerization time,
Polymerization is preferably performed for 60 minutes or less, and more preferably for 50 minutes or less, and high quality with a narrow molecular weight distribution free of unreacted monomer content, ultra-high molecular weight (molecules having extremely high molecular weight and hardly soluble in water) or gelation product. The polymer of can be manufactured. After the polymerization is completed, the polymer is neutralized with a neutralizing agent.

The neutralizing agent is a powder of an alkaline earth metal hydroxide or an alkali metal carbonate, which forms spherical fine particles having a low hygroscopic property upon neutralization to obtain a product having excellent solubility. It is preferable from the point. In particular, alkali metal carbonates are preferable because molecular cleavage is unlikely to occur, spherical fine particles are easily formed, and moisture absorption resistance and solubility can be greatly improved. In the case of alkali metal carbonate, the generated carbon dioxide gas and water can reduce the uniform neutralization reaction and the viscous resistance.

The powder (neutralizing agent) has a particle size range of 4
It is preferably 0 to 100 mesh from the viewpoint of preventing hygroscopicity, solubility, and workability such as weighing and subdivision.

The amount of the neutralizing agent used is 0.5 to 1.5 mol, based on 1 mol of the acid contained in the obtained polymer.
Further, it is preferably 0.9 to 1.1 mol from the viewpoint of obtaining a mortar flow value and a spherical powder having a commercial grade (high grade).

The peripheral speed of the blades of the stirrer at the time of neutralization,
The temperature and the like are preferably the same as those at the time of polymerization, from the viewpoint of preventing hydrolysis, depolymerization, molecular cleavage, crosslinking, gelation and the like.

The polymer after the neutralization may be obtained by distilling off the volatile components under reduced pressure and pulverizing it into a product. Also, the polymer has such a viscosity that it can be filled and taken out in a can such as a drum, a lorry or a gallon can. It may be diluted by adding water until it becomes a product.

When the product is added with water, it is sufficient to add water to the polymer to dissolve it uniformly and to neutralize it. In this case, the neutralizing agent need not be limited to the alkaline earth metal hydroxide or alkali metal carbonate suitable for pulverization,
Neutralizing agents such as alkali metal hydroxides, ammonia and amines can also be used.

Since the liquid cement additive produced in this manner is polymerized at a high concentration, the polymerization time is short, and the production amount per polymerization vessel is large and the productivity is high. In addition, since high-concentration polymerization is performed uniformly and all at once in a short period of time, the molecular weight distribution is narrow, and it is possible to obtain extremely low-grade products such as unreacted monomers, low-molecular weight polymers, ultra-high polymers and cross-linked polymers. .

On the other hand, when the volatile components are distilled off under reduced pressure and powdered into a product, dehydration under reduced pressure is performed to a water content of 3% or less before adding the neutralizing agent, and then the neutralizing agent is added and dehydration is performed under reduced pressure. Alternatively, at the time of neutralization, 20% or less of the total weight, and further 1
It is preferable to add 0% or less and 3% or more of a poor solvent to pulverize and distill off the volatile components under reduced pressure, because spherical particles of 5000 μm or less are generated immediately, which reduces the crushing step. In addition, the neutralizing agent is uniformly dispersed (after adding the neutralizing agent,
Stirring is stopped with time, sampling is performed from three points along the circumference, and the acid value is measured. The values at the three points are theoretical acid values ± (meth) acrylic acid-based monomer × 0.00
5 (0.5%) to determine that), the peripheral speed of the blades of the stirrer is gradually lowered to 90 m / min or less while gradually lowering the inner temperature so that the inner temperature does not rise. By concentrating under reduced pressure and drying to dryness so as to maintain the temperature at 90 ° C. or lower, it is possible to prevent alteration of the powder due to heat generation by shearing (generation of gelled product due to radical radicals for molecular cutting).

The powdered cement additive produced in this way has a particle size range of 5,000 to 100 after crushing.
.mu.m, spherical particles consist of a combination of particles of almost 50-500 .mu.m, and contain almost no irregular fine particles,
It is a product that has low hygroscopicity, excellent solubility in water, excellent mortar flow properties with excellent mixing and dispersibility in cement, and is easy to handle.

Next, the case where the method of the present invention is manufactured by one reactor as shown in FIG. 1 and the case of manufacturing by two reactors as shown in FIG. 2 will be described.

As a concrete example of the reactor having the lower bearing type agitator, for example, as shown in FIG. 1, a reactor used for continuously performing an initial polymerization reaction, an aging polymerization reaction, and a pulverization in one reactor, Using two reactors as shown in FIG. 2, in the first reactor, the monomer and the polymerization initiator are brought into contact with each other instantaneously to control the heat of polymerization, and the initial polymerization reaction having a narrow molecular weight distribution in a short time, In the second reactor, the reaction product obtained by converting about 90% or more of the monomers in the first reactor is aged, and the unreacted monomer is 1% or less, and the aging polymerization reaction and neutralization are performed. Examples include two reactors used to add powders of powders, to perform uniform dispersion and neutralization instantaneously, dehydration and desolvation under reduced pressure, and to perform pulverization mainly of spherical fine particles. Although it is not intended to be limited thereto.

When the initial polymerization reaction, the aging polymerization reaction and the powdering are continuously carried out in one reactor,
Since only one reactor is required, the equipment cost is low, and it is preferable from the viewpoint that a more uniform product with a sharp molecular weight distribution can be obtained. Also, using two reactors, the first reactor can be used. In the initial polymerization reaction, in the second reactor, when the reaction product obtained in the first reactor is aged and pulverized, the initial polymerization reaction, which is difficult to control the reaction, can be easily controlled in a small amount. By carrying out the step (1), the polymerization can be carried out safely and with a constant quality, and the aging and pulverization after the reaction can be easily controlled can be carried out in a large amount to improve the productivity. For the second aging polymerization, the monomer, chain transfer agent and polymerization initiator are fed continuously and proportionally while the feed port is injected from the lower part of the first reactor and overflowed from the upper part. By employing the polymerization process to continue to supply the actor, productivity, stable quality, it can be improved.

In FIG. 1, 1 is a monomer tank, 2 is a polymerization initiator tank, 3 is a monomer measuring machine, 4 is a polymerization initiator measuring machine, 5 is a lower bearing type agitator, and 6 is a reactor having a lower bearing type agitator. 7 is a motor, 8 is a condenser, 9 is a condenser condensate holder, 10 is a vacuum pump, 11 is a pressure control valve, 12 is an open valve, and 13 is an outlet having a discharge valve.

The monomer from the monomer tank 1 and the polymerization initiator from the polymerization initiator tank 2 can be supplied to the reactor 6 having the lower bearing type agitator 5 through the respective weighing machines 3 and 4, The monomer tank 1, the polymerization initiator tank 2, the monomer measuring machine 3, and the polymerization initiator measuring machine 4 are connected to a reactor 6 having a lower bearing type agitator 5.

Further, the condenser 8 is connected to the reactor 6 having the lower bearing type agitator so that the volatile matter from the reactor 6 having the lower bearing type agitator can be cooled, condensed, and recirculated, and the valve can be switched. The condenser condensate holder 9 is connected to the condenser so that the cooling / condensate from the condenser accumulates in the condenser condensate holder 9. The system pressure can be controlled to normal pressure, pressurization, or depressurization by switching the vacuum pump 10, the pressure control valve 11, and the opening valve 12 provided in the exhaust line.

The lower bearing type agitator 5 is driven by a motor 7.

When the cement additive is produced using the apparatus shown in FIG. 1, the reactor 6 is charged with a monomer, a chain transfer agent, a polymerization initiator, and optionally a solvent such as water. The monomer and the polymerization initiator may be charged from the monomer tank 1 and the polymerization initiator tank 2 through the monomer measuring machine 3 and the polymerization initiator measuring machine 4. The chain transfer agent and a solvent such as water used in some cases may be mixed with the monomer and charged from the monomer tank 1, or may be charged by separately providing a line.

The raw materials may be charged intermittently or continuously while carrying out the polymerization reaction from the viewpoints of productivity, safety, and stability / improvement of quality. Further, the cost of the equipment is reduced and the production in small quantities is possible. In order to control the quality easily, the whole amount may be charged all at once, but when polymerization, aging, neutralization and pulverization are carried out by one reactor as shown in FIG. Polymerization, neutralization, and pulverization are preferable from the viewpoints of safety, quality, and productivity because instrument costs for automatic and unmanned control are simple and the operation is simple.

The use ratio of the above-mentioned monomer, chain transfer agent, polymerization initiator and solvent optionally used is such that the monomer concentration is 75% or more, further 80% or more, especially 85% or more, particularly 90%. The above is preferable in view of productivity, quality, particularly hygroscopic resistance of powder, solubility, and handleability, and the rest is only a chain transfer agent and a polymerization initiator without using a solvent. It is preferable in terms of solvent recovery and recycling, and reduction of waste liquid treatment cost.

When the monomer does not melt even at the polymerization temperature, water or an organic solvent is added so that the monomer is melted at the polymerization temperature, and the monomer is uniformly dissolved, stirred, dispersed, preferably at a concentration close to that of the bulk polymerization. It is preferable to control the heat of polymerization by polymerization and reduce the torque of the machine. In this case, a large amount can be charged, and spherical particles are easily formed.

For example, methoxypolyethylene glycol (meth) acrylic acid ester having a high molecular weight and (meth)
When the acrylic acid-based monomer or the (meth) acrylic acid-based monomer and the other vinylcarboxylic acid monomer are mixed and copolymerized, the polymerization temperature is 60 to 93 ° C., and further 6
In order to carry out uniform polymerization at 5 to 90 ° C., an organic solvent or water may be added to lower the melting point and viscosity of the monomer so that a uniform reaction can be carried out.

Further, the melting point of methoxypolyethylene glycol (meth) acrylic acid ester having a molecular weight of about 1000 is 30 to 40 ° C. When (meth) acrylic acid is added thereto at a polymerization ratio of 20% and mixed to be compatible, the melting point is However, when a small amount of chain transfer agent is added to this and the mixture is held in the service tank as a monomer mixture, if it is kept at a high temperature, thermal polymerization will start even without the addition of a polymerization initiator. Therefore, it is necessary to keep the temperature at 40 to 50 ° C. or lower, but the viscosity in this case is as high as several thousand to several tens of thousands cP (centipoise). To this, an aqueous polymerization initiator solution or a liquid or powdery polymerization initiator is added, and in order to homogenize within 60 seconds, a small amount of an organic solvent or water can be added to make the homogenization faster, A uniform reaction can be performed.

As the organic solvent, a parent solvent is preferable, but a poor solvent can also be used. When a poor solvent is used, it is possible to carry out a polymerization which is heterogeneous but is close to emulsion polymerization. When a poor solvent is used, it is not necessary to add a poor solvent, which is added if necessary during neutralization.

The polymerization temperature is preferably from 60 to 93 ° C., more preferably from 65 to 90 ° C., from the viewpoint of preventing ester hydrolysis and crosslinking due to heat radicals.

The polymerization temperature is usually controlled so as to be proportional to the polymerization concentration. For example, a monomer concentration of 75
In the case of ~ 80%, 60 ~ 65 ° C, in the case of 85%, 65 ~ 65
70 ° C, 90%, 70-75 ° C, 95%,
In the case of 75 to 80 ° C and around 100% (because the chain transfer agent and the polymerization initiator are used, it does not become 100%),
It is preferable to control the temperature to 80 to 93 ° C.

The temperature can be shifted to the low temperature side depending on the amounts of the chain transfer agent and the polymerization initiator. By increasing the amounts of chain transfer agent and polymerization initiator, the monomer concentration was increased to 8
The polymerization temperature can be controlled in the range of 65 to 75 ° C. in the vicinity of 0% to 100%. In this case, a product with good productivity and stable quality can be manufactured safely and reliably.

Polymerization temperature is less than 60 ° C., monomer concentration is 7
When it is less than 5%, the polymerization time and the concentration time are long, and the hydrolysis and elimination of the alkoxyalkylene glycol group are likely to occur during the concentration. When the temperature exceeds 93 ° C, the alkoxyalkylene glycol group is present even if a small amount of water is present. It is easy to cause hydrolysis and elimination of the polymer, and molecular cleavage and three-dimensionalization by thermal radicals and formation of a branched polymer are likely to occur.

The polymerization pressure is 0.098MP.
a (1 kg / cm ² · G) (normal pressure) is safety,
It is preferable in terms of operability of the apparatus, but 0.100 to 0.
The range of 196 MPa (1 kg / cm ² · G) is
It is preferable in that hydrolysis of the alkoxy polyalkylene glycol (meth) acrylic acid ester is suppressed.

A pressure control valve is attached to the reactor, and when charging a monomer or a polymerization initiator, the pressure is opened to normal pressure, but a maximum of 0.196 MPa (1
(Kg / cm ² · G) by keeping the inside pressure, in the case of polymerizing in a water-containing system, for example, 80 to 99%, particularly at 75 to 90 ° C., an alkoxypolyalkylene glycol (meth) acrylic ester It is possible to prevent the degradation of the performance due to the hydrolysis of the polymer, the molecular weight distribution, gelation and branching. Pressure,
Keeping the pressure higher than 0.196 MPa (1 kg / cm ² · G) not only raises the cost of the apparatus and the risk at the time of reaction, but also raises the effect little. For example, when 90% of methoxy polyethylene glycol methacrylate (10% of water) is kept at 90 ° C. for 60 minutes, the hydrolysis rate is about 5% at normal pressure (0.098 MPa), while the hydrolysis rate is 0.147 MPa ( 0.5
kg / cm ² · G), about 0.1%, 0.196M
When Pa (1.0 kg / cm ² · G), about 0.05
%, 0.294 MPa (2.0 kg / cm ² · G), about 0.04%, 0.196 MPa (1.0 k
Even if a pressure exceeding g / cm ² · G) is applied, it is not so effective in lowering the hydrolysis rate.

In the present invention, when the cement additive is produced using the monomer, the chain transfer agent and the polymerization initiator, since the polymerization is carried out by using the reactor having the reactor having the lower bearing type agitator, The transfer agent and the polymerization initiator can be batch-continuously polymerized while instantaneously and uniformly contact-dissolving (compating). Therefore, the polymerization time during the initial polymerization is 5 to 30 minutes, and further 10
It can be ~ 25 minutes. The subsequent aging time is 2
0 minutes or more, preferably 60 minutes or less, further 25 to 50
In addition, it is possible to carry out uniform polymerization in a short time, and to obtain a commercial grade polymer having a uniform molecular weight and a small amount of unreacted monomers, low molecular weight polymers, ultra-high polymers, cross-linked polymers and branched polymers. You can

Regarding the stirring speed of the lower bearing type agitator at the time of carrying out the polymerization, the peripheral speed of the side blades of the agitator is 90 to 60.
0 m / min, and even 100-500 m / min, especially 1
It is preferably 20 to 400 m / min, particularly 150 to 300 m / min from the viewpoint of instantaneously and uniformly mixing, compatibilizing, and reacting to prevent molecular cleavage and heat generation. For example, in the case of a kneader or a suspended reactor production machine used as a conventional high-viscosity reactor, it is used at 30 rpm or less, further 20 rpm or less in order to avoid mechanical overload, but the diameter (rotation diameter) is 1 m. In case of the blade of No. 3, the peripheral speed is 3.
14 × 0.5 × 2 = 3.14 m / revolution, so 9
It will be 4.2 m / min. Usually, the peripheral speed in the apparatus used for various polymerizations is generally 30 to 90 m / min.

The polymerization temperature may be controlled by controlling the jacket temperature of the reactor 6. monomer,
A chain transfer agent, a polymerization initiator and, if necessary, a solvent are charged in a predetermined order, a lower bearing type stirrer is operated under predetermined conditions, and the charged components are instantly made homogeneous and compatible, The monomer conversion can be 90% or more in 30 minutes, preferably 10 to 25 minutes. When the temperature of the refrigerant is normal water cooling (20 ° C.), the capacity of the reactor (in other words, the relationship of the charged amount of polymerization) is 1500 L at maximum.
(Preparation amount 700 kg), preferably 1200 L (preparation amount 500 kg), 1000 L (preparation amount 3
00 kg) or more is preferable. The capacity of the reactor does not need to be further reduced, but may be smaller (for example, a bench scale of about 30 L may be used). The temperature of the refrigerant is preferably 60 to 90 ° C, preferably 65 to 85 ° C during the initial polymerization. When using the reactor of FIG. 1, even if chiller water or brine is used as the refrigerant, the polymer is a highly viscous substance, and due to the thermal conductivity,
Not very effective. Further, when the reaction apparatus of FIG. 1 is used, heating is required at the time of aging, so that it is not so effective from this point as well.

The capacity of the reactor is the capacity up to the upper end of the jacket.

When 90% or more of the monomer is converted into a polymer, the heat of polymerization hardly occurs. Therefore, by heating the jacket to 60 to 90 ° C, preferably 65 to 85 ° C, the internal temperature is kept for 10 to 20 minutes. Although the monomer conversion becomes 99%, it is preferable to set the aging time to 20 minutes or more, just in case, but 60 minutes or less.

If the conversion after the completion of the initial polymerization is 90% or more, the molecular weight distribution is uniform to about 5,000 to 100,000, and the average molecular weight is around 15,000, there is no change in the mortar flow value (JIS method) when added to cement. monomer odor when residual monomer, yield, waste water, a problem such as the performance is caused, preferably performed ripening polymerization prospect for more than 20 minutes.

Although it depends on the kind and mixing ratio of the monomers, the kind and addition ratio of the polymerization initiator and the chain transfer agent, and the polymerization temperature, in the case of initial polymerization, it is usually 25 at a monomer concentration of 75%
~ 30 minutes, 85% for 20-25 minutes, 90% for 15-20
%, 95% to 10 to 15 minutes, and 100% to 5 to 10 minutes, about 90% or more of the monomer is converted into a polymer, and aging polymerization can be performed. In the above example, the fastest one takes 5 minutes and the slowest one takes 30 minutes. Usually, in order to produce stably and safely, the concentration and temperature of the monomer, the chain transfer agent and the polymerization initiator are controlled, 5-30
It is preferred to complete the initial polymerization in minutes.

After the completion of the polymerization, the powder is pulverized and neutralized to improve the mortar flow value. The neutralizing agent for neutralization is a powder of an alkaline earth metal hydroxide or an alkali metal carbonate. It is preferable from the viewpoint of producing fine particles of powder in a high yield.

As a method of adding the neutralizing agent used at the time of neutralization, neutralization equivalents are added all at once from the manhole, and stirring is continued for about 5 minutes from the time when the mixture becomes uniform (the time required for uniformization depending on the stirring speed). Is different, but at 300 m / min,
It becomes uniform within 1 minute. Continue stirring for about 5 minutes to ensure the neutralization reaction), reduced pressure, preferably about 5333 ±
2667 Pa (40 ± 20 torr), jacket temperature 6
The solvent, water or produced water used at 0 to 100 ° C. is preferably dried under reduced pressure.

The temperature at the time of neutralization is 60 to 90.
C., more preferably 65 to 80.degree. C., from the viewpoints of molecular scission due to viscous resistance, neutralization reactivity, and spherical particle production rate, and the stirring speed of the lower bearing stirrer is 90.
~ 600 m / min, even 100-500 m / min, especially 120-400 m / min, especially 150-300 m
/ Min means that evenly mixed, compatible, and reacting instantaneously
It is preferable from the viewpoint of preventing molecular cleavage and heat generation.

When the neutralization is carried out with a caustic alkali, hydrolysis occurs due to the heat of neutralization and high alkalinity, the alkoxypolyalkylene glycol group is eliminated, and the performance tends to deteriorate (however, after completion of the polymerization, the drum, When water is added to dilute the mixture until it has a viscosity that allows it to be filled or taken out in a lorry or a can, and then neutralized with a caustic alkali, the above problems are mostly solved). By neutralizing with a powder of alkali carbonate or alkaline earth metal hydroxide, especially after high-concentration polymerization or low-concentration polymerization and concentration, a polymer concentration of 75% or more, further 80% or more When it is neutralized, it can be neutralized more uniformly than the caustic aqueous solution without causing hydrolysis.

The reason for this is that, in the case of alkali carbonate, when a high-concentration (about 75% to 100%) viscoelastic polymer viscoelastic body and alkali carbonate powder come into contact with each other, carbon dioxide gas and water are generated. And foam.

[0104]

[Chemical 1]

When foaming, the high viscoelastic polymer is finely pulverized, and the neutralization is completed in a short time as if an alkaline aqueous solution was added to the polymer having a low concentration and a low viscosity to stir and neutralize. In the case of ash, to take water of crystallization,
The reaction product water and the contained water are adsorbed at a high speed, and this also serves as a rapid disintegration aid in the viscoelastic region of the molecule.

As a result, it is considered that hydrolysis of the polymer, molecular cleavage, cross-linking due to cleavage (shearing) radicals, etc. hardly occur, and the powder is converted into spherical powder in a short time in synergy with the stirring granulation function of the reactor. .

On the other hand, when the alkaline earth metal hydroxide powder is used, it has low solubility in water (water contained in the polymer and water produced during neutralization) and in the polymer, and Since it is taken as crystallization water, a neutralization reaction occurs while the viscoelastic polymer is crushed in a relationship like rice cake and flour, and as the neutralization progresses, the neutralized polymer greatly decreases its affinity for water and rapidly Powdering progresses.
The obtained powder is considered to be spherical fine particles without uniform lumps and aggregates thereof.

Thus, when the alkali metal carbonate is used as the neutralizing agent and the neutralization is carried out under a reduced pressure of about 5333 ± 2667 Pa (40 ± 20 Torr), the polymer foams to form a thin film (soap bubble). Therefore, it is uniformly neutralized and crushed into a uniform powder. Due to the high evaporation rate of residual water and neutralized water, the polymer content is 75% or more, and even 80%.
% To 1% or more, neutralized with caustic, and vacuum dried for 1/5 to 1/10 to complete neutralization and pulverization. Since the formed powder particles are spherical fine particles and aggregates thereof, they have low hygroscopicity. Even in the case of crushing (in this case, crushing), there is no coarse particle containing a large amount of water, so the crushing (crushing) efficiency is high.

When an alkaline earth metal hydroxide is used as a neutralizing agent, it can be neutralized and powdered under almost the same conditions as when an alkali metal carbonate is used.

Before adding the neutralizing agent, dehydration is performed under reduced pressure to a water content of 3% or less and the neutralizing agent is added to dehydrate under reduced pressure, or at the time of neutralization, 20% or less, more preferably 10% based on the total weight. % Or less and 3% or more, and further 7% or more of poor solvent is added,
60 to 90 ° C, stirring speed of lower bearing type stirrer 90 to 60
By uniformly dispersing and slurrying (wet crushing and granulating) under the condition of 0 m / min to make wet powder, and after wet powdering, the poor solvent and the solvent used at the time of polymerization are distilled off under reduced pressure. Polymer is the particle size required for cement additives 5
Most of the polymers can be pulverized at once in the reactor to 000 μm or less, further 1000 to 100 μm, and the crushing step can be omitted or the crushing time can be shortened, which is preferable.

Further, from the stage where the neutralizing agent is uniformly dispersed, the peripheral speed is reduced to 60 ° C. at the maximum by the steps of gradually reducing the peripheral speed so that the product temperature becomes 90 ° C. or lower and concentrating and drying.
By lowering from 0 m / min and finally to 90 m / min or less, it is possible to prevent alteration of the powder due to heat generation due to shearing (generation of gelled product by molecular cutting radicals, etc.).

Examples of the poor solvent include chlorine-based solvents such as trichlene and dichloromethane, benzene, toluene, cyclohexane, n-alkanes and the like.

The powder obtained by distilling off the solvent and water was 9
9% or more can be made into spherical fine particles of 5000 μm (0.5 mmφ) or less, which easily becomes uniform when mixed with cement, does not easily become muddy, and easily dissolves in water uniformly to obtain a high-performance good product. You can

A preferable product having less blocking due to moisture absorption of powder during the packaging, storage and use after production and a container or a loss of dust adhered to the packaging material can be obtained. This product does not need to be crushed (crushed), and when used as a liquid product, it can be smoothly dissolved in a short time without causing blocking simply by injecting (putting) it into a stirring water tank.

Since the poor solvent that has been distilled off can be separated and recovered from water and reused, it is extremely unlikely to cause a problem in terms of cost and environment.

In the above description, the produced polymer was pulverized, but water was added without adding a poor solvent at the time of neutralization to a predetermined concentration, for example, when filling in a drum, lorry, or a 5 gallon can, filling and withdrawing. The product may be diluted by adding water until the viscosity becomes possible.

In this way, polymerization is carried out at a high concentration,
Cement additives can be produced. Also, the manufactured cement additive can be made into powder. For example, when the monomer concentration is 80%, it can be carried out in about 2 hours from polymerization to neutralization and pulverization, in about 1 hour when the monomer concentration is 90%, and in about 30 minutes when the monomer concentration is around 100%. .

FIG. 3 is an enlarged explanatory view of the reactor having the lower bearing type agitator of the apparatus having the reactor having the lower bearing type agitator in FIG.

In FIG. 3, the preferred shape of the reactor 6 having the lower bearing type agitator has a diameter (0.2 to 2 m).
The height (depth of the tank) is 2 to 3 times the diameter (0.4 to
4 m to 0.6 to 6 m, preferably smaller for initial polymerization described later and larger for aged polymerization). The reactor has a jacket 31 so that it can be heated and cooled.
Is attached and has a thick structure that can withstand pressure and decompression. The stirring shaft 32 is composed of a shaft seal portion, a shaft and a bearing portion at the bottom of the tank, and the shaft seal portion may be any of a mechanical seal, an oil seal and a gland seal. As for the shaft, the pulley may be driven by an inverter motor by a belt or a hydraulic motor. The shaft should be in horizontal contact with the bottom of the tank (the gap is 0.5 to 2.0 mm, and even 0.5 to 1.0 mm), and the material that adheres to and deposits on the bottom should be raised horizontally. The blades 33 are attached, and both ends of the horizontal blades 33 are almost in contact with the wall surface so as to scrape off the adhered matter on the wall surface if necessary (the interval is 0.5 to 5 mm, and further, 0.
5 to 3 mm) A rising vane 34 (the tip of the rising vane is preferably 1/3 to 1/2 of the height of the tank) is attached, and the shaft top (between the upper surface and the bottom surface of the reactor is a tank). If necessary, a horizontal blade 35 is provided at the bottom (1 / 3rd position from the bottom) of the horizontal blade 35, which has a tip that extends to near the wall surface of the tank and the center of the shaft. It is preferable that the tip be located approximately in the middle of the outer wall and the shaft)
Falling vanes 36 (preferably the tips of the vanes are approximately in the middle between the horizontal vanes 33 and 35) for breaking up the agglomerates. The blade portion of the blade is preferably a knife blade, but if necessary, it may be processed into a saw blade or a comb shape. Further, when taper processing is applied to the back side of the surface of the blade that is almost in contact with the wall surface and the bottom surface, phenomena such as sticking, adhesion, baking, overload, and solidification can be prevented.

The horizontal blades 35 hold down the substance to be lifted up, and crush the solid mass generated in the space (dead zone) between the horizontal blades 33 and the central shaft to instantly make uniformly different compositions. It serves to mix.

As described above, since the horizontal blades 33 and the rising blades 34 are close to the bottom surface and the wall surface, the deposits and the deposits can be scraped off. Further, the horizontal blades 35 and the falling blades 36 disintegrate and disperse the substance to be agglomerated and form a circumferential motion at any part, so that uniform mixing and spherical granulation and disintegration can be performed. .

In the apparatus shown in FIG. 1, a plurality of reactors 6 each having a lower bearing type agitator may be provided side by side to share the monomer tank 1 and the polymerization initiator tank 2.

Further, as shown in FIG. 1, in the case where the initial polymerization reaction is repeated in one reactor for pulverization (manufacturing in the case of producing a liquid product), the inner surface (wall surface or stirring blade) of the reactor from which the powder is discharged is repeated. Etc.) with a solution of a polymerization initiator (for example, an aqueous solution) to remove residual catalyst poisons, and then carry out the next polymerization because the next polymerization can be performed without completely cleaning the reactor. preferable.

In the above description, the case where the initial polymerization reaction, the aging reaction and the pulverization are continuously carried out in one reactor has been described. However, the initial polymerization reaction in the first reactor and the first polymerization reaction in the second reactor are performed. When aging and pulverizing the reaction product obtained in the second reactor, it is generally as follows. In addition, if the second reactor is made into two and one is pulverized, and the other is subjected to the aging reaction, it is not necessary to stop the first reactor.

In FIG. 2, 1 is a monomer tank, 2 is a polymerization initiator tank, 3 is a monomer meter, 4 is a polymerization initiator meter, 5 is a lower bearing type agitator, 7 is a motor, 8 is a condenser, and 9 is a condenser. Condenser condensate holder, 10
Is a vacuum pump, 11 is a pressure control valve, 12 is an open valve, 14
Is a reactor for initial polymerization having a lower bearing type agitator, 1
5 is a lower bearing type agitator, 16 is a aging reactor having a lower bearing type agitator, 17 is a motor, 18 is a condenser, 19 is a condenser condensate holder, 20 is a vacuum pump, 21 is a pressure control valve, 22 is an open valve, Reference numeral 23 represents an outlet having a discharge valve, and 24 represents an initial polymer transfer valve.

As in the case of FIG. 1, the monomer from the monomer tank 1 and the polymerization initiator from the polymerization initiator tank 2 pass through the respective weighing machines 3 and 4 and have the lower bearing type agitator 5 for the initial polymerization reactor. It is connected to an initial polymerization reactor 14 having a lower-bearing stirrer 5 so that it can be fed to.

Further, the condenser 8 is connected to the initial polymerization reactor 14 having the lower bearing type agitator so that the volatile matter from the initial polymerization reactor 14 having the lower bearing type agitator can be cooled, condensed and refluxed. The condenser condensate holder 9 is connected to the condenser so that the cooling / condensate from the condenser is accumulated in the condenser condensate holder 9 by switching the valve. The system pressure is the vacuum pump 1 installed in the exhaust line.
By switching between 0, the pressure control valve 11 and the open valve 12, normal pressure, pressurization and decompression can be controlled.

The lower bearing type agitator 5 is driven by a motor 7.

When the cement additive is produced using the apparatus shown in FIG. 2, the reactor 14, a monomer, a chain transfer agent, a polymerization initiator, and optionally a solvent such as water are charged.
The monomer and the polymerization initiator may be charged from the monomer tank 1 and the polymerization initiator tank 2 using the monomer measuring machine 3 and the polymerization initiator measuring machine 4. The chain transfer agent and a solvent such as water used in some cases may be mixed with the monomer and charged from the monomer tank 1, or may be charged separately by providing a line.

From the viewpoints of cost, safety, enlargement of polymerization, mass production, and reduction of investment during mass production, the raw materials are intermittently aged and neutralized while continuously carrying out the initial polymerization reaction. -Powdering may be performed, and in order to obtain a product having a uniform and narrow molecular weight distribution, the whole amount may be charged all at once, but polymerization by two reactors as shown in Fig. 2,
When aging and pulverizing, it is preferable from the viewpoint of economy, quality and stable control that the aging reaction is continuously performed while intermittently performing the initial polymerization reaction.

The use ratio of the monomer, the chain transfer agent, the polymerization initiator and the solvent used in some cases is such that the monomer concentration is 75% or more, further 80% or more, especially 85% or more, particularly 90%. The above is preferable in that a product-grade product can be produced at low cost, and the rest is only a chain transfer agent and a polymerization initiator without using a solvent. It is preferable because it can be produced.

When the monomer does not melt at the polymerization temperature, water or an organic solvent is added so that the monomer does not melt even at the polymerization temperature, and the monomer is hydrolyzed at a concentration preferably close to that of the bulk polymerization so that the monomer is hydrolyzed or decomposed. It is preferable to prevent the formation of a cross-linked product or a branched polymer due to shear radicals or heat radicals of the polymer, and obtain a desired molecular weight and particle shape.

The polymerization temperature is preferably from 60 to 93 ° C., more preferably from 65 to 90 ° C., from the viewpoint of not causing the molecular weight, hydrolysis, crosslinking or branching due to molecular cutting radicals or heat radicals.

The polymerization pressure is usually 0.09.
8 MPa (normal pressure) is preferable from the viewpoint of equipment cost and operability, but slight pressure (0.1 kg / cm ² · G) to
The range of 0.196 MPa (1 kg / cm ² · G) is preferable from the viewpoint of suppressing hydrolysis of the alkoxypolyalkylene glycol (meth) acrylic acid ester. If there is no water, normal pressure may be used.

In the batch type batch-injection polymerization, the reactor for the initial polymerization is 1500 L or less, the charged amount is 700 kg or less, preferably 1200 L or less, the charged amount is 500 kg or less, and the productivity is 1000 L or more in batch batch polymerization. The amount of 300 kg or more is preferable, and the reactor for aging polymerization has a maximum of 5000 L from the operating cost and the equipment cost.
3000 L, and more preferably 2000 L are suitable. If it is too large, coarse particles are likely to be formed, and in order to obtain a fine spherical powder (increase the crushing rate), it is preferable that it is small, but from the viewpoint of productivity, about 2000 L is preferable.

In the present invention, when the cement additive is produced by using the monomer, the chain transfer agent and the polymerization initiator, the polymerization is carried out by using a reactor having an initial polymerization reactor having a lower bearing type agitator. The monomer, the chain transfer agent, and the polymerization initiator can be batch-continuously polymerized while instantaneously and uniformly contact-dissolving (compating). Therefore, the polymerization time at the initial polymerization can be 5 to 30 minutes, further 10 to 25 minutes, and the subsequent aging time can be 20 minutes or more, preferably 60 minutes or less, further 25 to 50 minutes. It is possible to carry out uniform polymerization in a short time, and to obtain a commercial grade polymer having a uniform molecular weight and a small amount of unreacted monomers, low molecular weight polymers, ultra-high polymers, cross-linked polymers and branched polymers.

The stirring speed of the lower bearing type stirrer at the time of carrying out the initial polymerization may be the same as that at the time of carrying out the polymerization using the reactor of FIG.

Monomer concentration of 75% or more, further 80%
As described above, preferably, in bulk polymerization, the reactor 14 for initial polymerization has a polymerization temperature of 60 to 93 ° C., preferably 65 to 90 ° C., by controlling (cooling) the jacket temperature.
The monomer mixture and the chain transfer agent are separately or uniformly mixed and metered in while controlling so that the polymerization initiator is metered in, and instantly homogeneously compatible or dispersed. Minutes, preferably 10-2
The monomer conversion can be increased to 90% or more in 5 minutes. When the temperature of the refrigerant is normal water cooling (20 ° C.), the capacity of the initial polymerization reactor 14 (in other words, the relationship of the charged amount of polymerization) is 1500 L at the maximum (charged amount of 700 kg),
It is preferably 1200 L (a charge amount of 500 kg). From the economical point of view, it is not necessary to make it less than 1000 L (preparation amount: 300 kg). Even if you use chiller water or brine as a refrigerant,
Due to the relationship between high viscosity and thermal conductivity, it is not easy to make it larger than this.

When 90% or more of the monomer is converted into a polymer, the heat of polymerization is hardly generated. Therefore, the monomer is transferred to a large-scale aged polymerization reactor and kept at 60 to 90 ° C., preferably 65 to 85 ° C. while maintaining the internal temperature. By keeping the temperature, the monomer conversion rate is 9 in 10 to 20 minutes.
Although it will be 9%, the aging time is preferably 20 minutes or more, just in case, but 60 minutes or less.

If the conversion after the initial polymerization is 90% or more, the molecular weight distribution is uniform to about 5,000 to 100,000, and the weight average molecular weight is 15,000 to 25,000, there is no change in the mortar flow value (JIS method) when added to cement. However, if monomer remains, monomer odor, yield, wastewater,
A problem such as the performance is caused, preferably performed ripening polymerization prospect for more than 20 minutes.

Although it depends on the kind of the monomer, the compounding ratio, the kind of the polymerization initiator or the chain transfer agent, the addition amount ratio and the polymerization temperature, in the case of the initial polymerization, it is usually 25 at a monomer concentration of 75%.
~ 30 minutes, 85% for 20-25 minutes, 90% for 15-20
%, 95% to 10 to 15 minutes, and 100% to 5 to 10 minutes, about 90% or more of the monomer is converted into a polymer, and aging polymerization can be performed. In the above example, the fastest one takes 5 minutes and the slowest one takes 30 minutes. Usually, in order to produce stably and safely, monomer, chain transfer agent,
By controlling the concentration and temperature of the polymerization initiator,
It is preferable to complete the initial polymerization in 30 minutes.

In the above description, the initial polymerization is carried out by an intermittent (batch type) method, the polymer is transferred to the reactor for aging polymerization, and the cement additive is continuously produced.
Initial polymerization reactor 14 and aging polymerization reactor 16
In the case where the initial polymerization is continuously performed by linking with the above, the polymerization is performed from the upper part of the initial polymerization reactor 14 while injecting the monomer, the polymerization initiator and the chain transfer agent from the lower part (bottom surface) of the initial polymerization reactor 14. By transferring the product to the reactor 16 for aging polymerization in the form of overflow, it is possible to continue the initial polymerization and the aging polymerization in different reactors (FIG. 4). At this time, by attaching the horizontal blades 33 of the lower bearing type agitator 5 to the bottom surface and removing the horizontal blades 35 (upper blades), the monomer, the chain transfer agent, and the polymerization initiator injected from the bottom are uniformly made instantaneously. Is
It is transferred to the upper layer while being converted to 90% or more by staying for 5 to 30 minutes (in this case, to make the conversion time faster). If the conversion is close to 90%, phase separation does not occur, so a continuous method is possible.

In this way, the jacket temperature of the reactor for initial polymerization was kept at 60 to 70 ° C., the monomer mixture was metered in (the chain transfer agent may be the same or different),
When the temperature of the monomer mixture reaches 60 ° C., a polymerization initiator is metered in and charged, the jacket is immediately switched to cooling, and the polymerization temperature is 60 to 90 ° C., preferably 65 to 75 ° C.
Adjust the jacket temperature to cool or heat to keep it at ℃. Hydrolysis of the monomer can be suppressed by simultaneously charging the polymerization initiator and sealing the reactor by using a pressure control valve and holding the reactor in a slightly pressurized system by raising the temperature. If abnormal polymerization occurs and the internal pressure rises so much that the pressure cannot be released by the pressure control valve, the pressure may be released by a release valve attached for safety.

When the monomer conversion rate is 90% or more, the heat of polymerization is not generated. Therefore, at this point, it is transferred to a reactor for aging polymerization and aging polymerization is carried out.

The neutralization after completion of the polymerization may be the same as in the case of one reactor.

The polymer produced and neutralized had
As in the case of the two reactors, water may be added to dilute the product to a predetermined concentration to give a product, or powder may be used to give a product.

The reactor for initial polymerization is equipped with an inlet for monomers, a chain transfer agent, a polymerization initiator and the like, a pressure holding control valve, and a discharge valve. Further, the reactor for aging polymerization is equipped with a neutralizer inlet, reduced pressure, distillation, a drying line, and a product discharge valve.

The apparatus of the present invention preferably has a flat bottom surface, but may be a semicircular type (Kagami type, that is, Kawata type). It is ideal that the clearance between the blades and the wall surface be zero in order to scrape off the product that adheres to the bottom and side surfaces, but considering the thermal expansion of the machine, adjust it to 0.5 to 5 mm depending on the size of the reactor. Preferably.

In a normal high-viscosity reactor, such as a horizontal kneader or a paddle type drier, adhesion occurs due to the low rotation speed, so it is difficult to polymerize, concentrate, and dry the polymer from liquid to powder. Is.

The above-mentioned reactor having the lower bearing type agitator used in the present invention has a low adhesion and residual rate, and can solve the problems of torta and the pressure holding (pressurizing, depressurizing) problems. From, for example, those described in Japanese Patent Publication No. 5-12372 of Sanso Micron,
Kawata's super mixer type, Fukae Kogyo's flat bottom mixer type, Pawreck's mixer type,
It is also possible to use a mixer type reactor manufactured by Nara Machinery Co., Ltd. in the method of the present invention. Also, in the reactor described in Japanese Patent Application No. 2000-182939 by the present inventors, since the scraping blades are attached in a special direction, a considerably large torque is generated at the solid-liquid branching point where the powder is pulverized. Partial adhesion may occur but can be used in the method of the invention.

As described above, the device of the present invention (high torque,
It has a high shearing force, can pressurize, depressurize, heat and cool, and can produce a uniform fine spherical particle powder from a liquid with a viscosity of 1 cP through a viscous body and a viscoelastic body). Therefore, preferably at a concentration close to that of bulk polymerization,
High-quality powder products can be produced in a short time in one pot.

In the present invention, a small amount of the chain transfer agent and the polymerization initiator are made compatible with each other in the monomer mixture in a short time (instantaneous state), or the monomers are not always separated but uniformly dispersed and uniformly contacted. For polymerization, for example, when a sodium methacrylic acid sulfonate chain transfer agent having a large polarity or a persulfate alkali salt polymerization initiator is used, polymerization with a monomer concentration of 75% or more has hitherto been carried out in a suspended reactor or a kneader. It was not possible, but this became possible, and at extremely high concentrations, thiol chain transfer agents and oil-soluble chain transfer agents such as α-methylstyrene dimer were used as chain transfer agents, and benzoyl peroxide and azoisobutyro In addition to using an organic polymerization initiator such as nitrile, instantaneous viscosity,
By using a reactor having a lower bearing type stirrer for uniformly dispersing and compatibilizing compositions having different compatibility, the monomer mixture and the chain transfer agent, or both of them and the polymerization initiator are instantly (1 to 60 seconds). It is possible to uniformly polymerize by mixing or dispersing.

[0153]

EXAMPLES In order to explain the present invention more specifically, the following examples are shown, but the present invention is not limited to these.

Example 1 In this example, a 30L reactor (hereinafter, also referred to as a reactor) having a lower bearing type agitator in the apparatus as shown in FIGS. 1 and 3 (reactor diameter 0.25) was used.
m, the height to the top of the jacket is 0.6 m, the flat bottom, the diameter of the horizontal blade 33 is about 0.249 m, the diameter of the horizontal blade 35 is 0.12
5 m, rising blade height 0.25 m, falling blade height 0.125 m, gap 0.5 mm between flat bottom and horizontal blade 33, gap 0.5 between wall surface and rising blade
mm), a monomer tank, a polymerization initiator tank, a condenser and a condenser condensate holder, the monomer tank and the polymerization initiator tank are connected to the reactor so that the monomer and the polymerization initiator can be fed to the reactor through a metering device. Connected, the condenser is connected to the reactor so that the volatile matter from the reactor can be cooled, condensed, and recirculated, and the cooling / condensate from the condenser is accumulated in the condenser condensate holder by switching the valve. Was used, and a pressure control valve was provided in the exhaust line, and by switching the valve, it was possible to control to normal pressure, pressurization, and depressurization.

The reactor jacket temperature was set to 65 ° C., and methoxypolyethylene glycol methacrylate (methoxy PEGMA) dissolved in advance at 60 ° C. (molecular weight 1000, manufactured by Shin Nippon Rika Co., Ltd.)
Mercaptopropionic acid (MPA) 150 in 8.3 kg
What added g was weighed in a weighing and mixing tank, charged into the reactor, separately charged with 150 g of azobisisobutyronitrile at the same time as 1.7 kg of methacrylic acid, and the stirrer was set to a peripheral speed of 300 m / min. Set and stir. The reaction started at the same time as the stirring and generated heat. After that, the peripheral speed 1
The temperature was adjusted to 50 m / min, and at the same time, cold water (20 ° C.) was controlled through the jacket so that the internal temperature was maintained at 65 to 90 ° C.

In order to check the mixed state of the raw materials, the reaction solution was sampled at three points on the circumference every minute and the acid value was measured to obtain the theoretical acid value (± 5% or less of the theoretical acid value). When the time was measured, it became uniform within 1 minute.

Further, in order to measure the conversion rate of the monomer, sampling was carried out every 5 minutes, rapid cooling and GPC measurement revealed that the conversion rate was 90% or more in 10 minutes.

The sampling was performed with stirring stopped for about 1 minute.

After that, the jacket temperature is adjusted to 65 to 70 ° C.
The reaction was stopped when the conversion reached 99.1%.

After the reaction, anhydrous sodium carbonate (soda ash) (manufactured by Tosoh Corp., particle size 50-100 mesh) 1.05k
When 1 g was added and 1 minute later, sampling was carried out at the above 3 points and the acid value was measured, the acid value at 3 points was constant (theoretical acid value ± acid value from methacrylic acid × 0.005
Within), and mixed uniformly.

Immediately reduce the pressure (about 5333 to 3997P).
a (40 to 30 Torr)), the jacket temperature was maintained at 90 ° C., the blade peripheral speed was gradually reduced from 200 m / min, and the internal temperature was maintained at 90 ° C. or lower. After adding the neutralizing agent 1
The powder granules changed from the viscoelastic region at 0 minutes. After changing to powder granules, the peripheral speed is reduced to 90 m / min or less, and the internal temperature is set to 9
The temperature was maintained at 0 ° C. or lower, and 15 minutes after the addition of the neutralizing agent, it was discharged from the discharge valve.

After cooling, the maximum particle size of the obtained powder granules is 5
In mmφ, 70% of spherical particles had a diameter of 0.5 mmφ (5000 μm) or less. When this was crushed with a 1.0 mmφ power mill (manufactured by Showa Giken Co., Ltd.), 98% was 50%.
The particles became spherical particles having a diameter of 00 μm or less.

The resulting spherical particles had a weight average molecular weight (G
PC) is 19300 (peak top molecular weight 19100)
The solubility in water was such that the jar tester dissolution time was 1 minute, the solution was a transparent liquid, and there was no cloudiness. In addition, the hygroscopicity is extremely low, and the sample 10g has a humidity of 60 ± 5
%, The time required to reach a water content of 10% was 81 minutes, there was no further moisture absorption, and no deliquescent was observed (it did not become sticky).

A mortar flow test (JIS A 1101 and JIS A 11) was performed using the obtained spherical particles.
26), the mortar flow value was 250 mm immediately after kneading, 210 mm and 240 mm after 30 minutes,
After 60 minutes they were 200 mm and 230 mm.

(Jar tester dissolution time) 500 cc of water was put in a 500 cc beaker, the rotation speed was set to 60 rpm, and 10 g of the polymer powder was put into the beaker, and the time until completely dissolved was measured.

(Mortar flow value) In a thermostatic chamber at 20 ° C., 0.1% of a cement additive to cement and a defoaming agent (a 100-fold diluted solution of a commercially available defoaming agent (CC-118)) in a mortar. Add 0.9g and 31.5g of water, low speed (60rpm
After 30 seconds of stirring, 90 g of cement was added, and 13.5 g of JIS standard sand was added in 30 seconds, and after 1 minute, the wall surface was scraped off for 2 minutes, followed by low-speed stirring for 2 minutes, and then Immediately after 30 minutes,
The flow value after 60 minutes was measured.

Comparative Example 1 Among the conventional polymerization machines, a 30L kneader (Nippon Roll Co., Ltd.) was used as an apparatus capable of high-concentration polymerization to powderization.
Manufactured) was selected and a comparative experiment was conducted.

With the same composition as in Example 1, the peripheral speed at the time of polymerization was set to a maximum mechanically possible value of 60 to 90 m / min.
The jacket temperature was controlled so that the internal temperature was the same as in Example 1, but the stirring efficiency and cooling efficiency were poor, and it was difficult to control the polymerization. After 7 minutes, the internal temperature rose to 110 ° C and the viscosity increased. , Gelled. After 120 minutes, the monomer conversion was 79%, so the powdering and mortar flow tests were discontinued.

Example 2 The same composition as in Example 1 (however, the polymerization initiator was an aqueous solution of 20% ammonium persulfate in an amount of 0.1 kg as pure matter and MP).
A was used (0.1 kg), 2.5 kg of water was added to adjust the monomer concentration to 78.7%, and slightly pressurized (0.049MP).
a (0.5 kg / cm ² · G)) was polymerized under the same conditions as in Example 1.
It took 35 minutes for the aging polymerization reaction. It should be noted that the sampling was performed by opening to normal pressure for about 1 minute.

Anhydrous sodium carbonate (soda ash) was added, and when the mixture became uniform, it was decompressed for neutralization and dehydration, pulverized in 25 minutes, and dispensed 30 minutes after the addition of the neutralizing agent.

The maximum particle size of the obtained powder powder is 8 mmφ
Then, when the proportion of 5000 μm or less was 60% and the powder was crushed with a power mill of 1 mmφ, the spherical fine particles had a proportion of 0.5 mmφ (5000 μm) or less and 95%.

The powder powder obtained had a weight average molecular weight of 1
9800, the peak top molecular weight is 18700,
As a result of the mortar flow test, the mortar flow value was 255 mm immediately after kneading, and the solubility in water was such that the jar tester dissolution time was 1.5 minutes and there was no cloudiness in the solution.
Moreover, the hygroscopicity is extremely low, and the sample 10 g has a humidity of
In a room of 0 ± 5%, the time to reach the water content of 10% is 75
There was no further moisture absorption in minutes and no deliquescent was observed.

Comparative Example 2 With the same composition as in Example 2, a reaction was carried out using a 30 L kneader at a peripheral speed of 60 to 90 m / min during polymerization.
It took 165 minutes to do more. At this time, when the polymer was dissolved in water, white zaku (a white undissolved mottle of the three-dimensionalized polymer, which was separated into two layers when the amount increased).

When the residual amount of the polymerization initiator was measured, it was almost zero. Therefore, when 0.5 part was added to carry out the reaction, it took 60 minutes to reach a conversion of 99% or more.

When 0.75 kg (pure content) of caustic soda diluted to 20% was added to the reaction product and dried under reduced pressure,
It took 105 minutes until powdering and 155 minutes until the caustic soda was charged and discharged (water content: 3% or less).

The peripheral speed of the stirrer was 10 m /
Although it dropped to the minute, it became overloaded and the motor stopped 5 times. As the powdering progressed, metallic noises were generated and the adhesion to the blades and the bottom was remarkable.

Regarding the maximum diameter of the dispensed product, about 50% of the 50 mmφ large lumps were included in the irregularly shaped powder, which had rubber elasticity and the water content was 2%. %
However, it was close to 5%. The yield when pulverized with a 1 mmφ power mill was 20%. Crystallization was performed at a low temperature (5 to 7 ° C.) for 3 days, and the pulverization was repeated 4 times, but the pulverization was not completed in the end. 0.5 mmφ (50
The total yield of 100 μm or less was 70%.

The obtained particle powder has a weight average molecular weight of 1
2000, peak top molecular weight 38,000, wide molecular weight distribution, mortar flow value 128m immediately after kneading
It was mφ.

When the obtained particle powder was observed with a microscope, it was an amorphous powder. As for hygroscopicity, it takes 5 minutes for a 10g sample to reach a water content of 10% in a room with a humidity of 60 ± 5%, and the jar tester dissolution time is that the portion that becomes lumps immediately after being dissolved in water dissolves. It took 25 minutes to settle and there was a precipitate of insoluble gel.

The results of Examples 1 and 2 and Comparative Examples 1 and 2 are summarized in Table 1.

[0181]

[Table 1]

Example 3 The polymerization initiator used in Example 1 was the ammonium persulfate (A
SP), benzoyl peroxide (BPO),
Spherical particles were produced in the same manner as in Examples 1 and 2 except that the polymerization initiator used in Example 2 was changed to azobisisobutyronitrile (AIBN) and benzoyl peroxide.

The weight average molecular weight, peak top molecular weight and mortar flow value of the obtained polymer were measured. The results are shown in Table 2 together with the results of Examples 1 and 2.

Further, the monomer concentration is 92%, 87.1%,
Spherical particles were similarly prepared for the 83% system.
The results are also shown in Table 2.

Ammonium persulfate (ASP) was used by appropriately selecting it from those having a concentration of 20 to 100%.

Comparative Example 3 An attempt was made to produce a polymer in the same manner as in Comparative Example 2 except that the polymerization initiator used in Comparative Example 2 was changed in the same manner as in Example 3, but gelation occurred. The results are shown in Table 2 together with the results of Comparative Example 2.

As a polymerization initiator, ASP was used.
In a system having a monomer concentration of 83%, it was attempted to produce spherical particles in the same manner, but gelation occurred. The results are also shown in Table 2.

[0188]

[Table 2]

Example 4 Polymerization was carried out under the same conditions as in Example 1 at a monomer concentration of about 97.1%, and the effect of the polymerization temperature on the 90% conversion time was examined. The results are shown in Table 3.

[0190]

[Table 3]

Reference Example 1 The same reactor used in Example 1 was charged with methoxypolyethylene glycol methacrylate and water for a total of 10 k.
g, charged so that the monomer concentration shown in Table 4 is obtained, 95-1
Methoxypolyethylene glycol concentration (hydrolysis rate) and holding pressure (gauge pressure) when held at 00 ° C for 1 hour
The relationship with was measured. The results are shown in Table 4.

The concentration (hydrolysis rate) of methoxypolyethylene glycol was measured using GPC.

[0193]

[Table 4]

Examples 5 to 7 A neutralizer (sodium carbonate anhydrous) was added to the polymer produced in the same manner as in Example 1, and then 5%, 10% and 20% of trichlene was added to the total content. (Example 5 in order
~ 7), neutralization and crushing was performed for 20 minutes. After that, the solvent (reaction water and trichlene) was distilled off under reduced pressure to obtain a particulate matter. The shape of the obtained particulate matter was examined. The results are shown in Table 5.

[0195]

[Table 5]

Example 8 Using a reactor having a 1500 L lower bearing type agitator, the charged amount was successively increased under the same conditions as in Examples 1 and 2 to carry out polymerization. The weight average molecular weight, peak top molecular weight and mortar flow value of the obtained polymer were measured. The results are shown in Table 6.

[0197]

[Table 6]

[0198]

According to the method of the present invention, the polycarboxylic acid type cement additive can be produced in a short time, with good quality and at low cost, and can be continuously pulverized.

[Brief description of drawings]

1 is an illustration of a reactor with one reactor that can be used when carrying out the process of the invention.

FIG. 2 is an illustration of a reactor with two reactors that can be used when carrying out the process of the invention.

FIG. 3 is an enlarged view of the reactor section shown in FIG.

4 is an explanatory diagram showing one embodiment of a method of connecting two reactors included in the reaction apparatus shown in FIG.

[Explanation of symbols]

1 Monomer tank 2 Polymerization initiator tank 3 Monomer weighing machine 4 Polymerization initiator weighing machine 5 Lower bearing type agitator 6 Reactor with lower bearing type agitator 7, 17 motor 8, 18 condenser 9, 19 condenser condensate holder 10, 20 vacuum pump 11, 21 Pressure control valve 12, 22 Open valve 13, 23 Discharge port with discharge valve 14 Reactor for initial polymerization having lower bearing type agitator 15 Lower bearing type agitator 16 Reactor for aging having lower bearing type agitator 24 Early Polymer Transfer Valve 31 jacket 32 stirring shaft 33, 35 horizontal blades 34 Standing blade 36 falling blades

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Claims (22)

[Claims] 1. A cement additive using a monomer containing an alkoxypolyalkylene glycol mono (meth) acrylic acid ester monomer and a (meth) acrylic acid type monomer as main components, a chain transfer agent and a polymerization initiator. A method for producing a cement additive, characterized in that, during production, a reactor having a reactor having a lower bearing type stirrer is used to continuously carry out from polymerization to pulverization. 2. The chain transfer agent is a water-soluble chain transfer agent and / or a water-insoluble chain transfer agent, and the polymerization initiator is a polymerization initiator aqueous solution, a polymerization initiator organic solvent solution or a polymerization initiator. The method according to claim 1, which is itself. 3. The peripheral speed of the blade of the stirrer is batched in the range of 90 to 600 m / min in order to instantaneously and uniformly contact dissolve (compatibility) or disperse the monomer, the chain transfer agent and the polymerization initiator. The method according to claim 1 or 2, wherein the polymerization is carried out continuously. 4. An initial polymerization for 5 to 30 minutes and an aging polymerization for 20 minutes or more by intermittently or continuously supplying the monomer, chain transfer agent and polymerization initiator to a reactor having a lower bearing type agitator. Item 4. The method according to Item 1, 2 or 3. 5. The method according to claim 4, wherein the initial polymerization time is 10 to 30 minutes. 6. The method according to claim 1, wherein the monomer concentration is 75% by weight or more. 7. The monomer concentration is a bulk polymerization or a concentration close to the bulk polymerization (concentration with or without addition of water or an organic solvent so that the monomer melts at the polymerization temperature). The method according to 4 or 5. 8. The method according to claim 1, wherein the polymerization temperature is 60 to 93 ° C. 9. The method according to claim 1, wherein the polymerization temperature is 65 to 90 ° C. 10. The polymerization pressure is 0.098 (normal pressure) to 0.
The manufacturing method according to claim 1, 2, 3, 4, 5, 6, 7, 8 or 9, wherein the pressure is in the range of 196 MPa (1 kg / cm ² · G). 11. A neutralizing agent used for neutralization after completion of polymerization is
The method according to claim 1, which is a powder of an alkaline earth metal hydroxide or an alkali metal carbonate. 12. A moisture content of 3% by weight before adding the neutralizing agent.
Dehydrating under reduced pressure and adding a neutralizing agent to the following:
The method according to 3, 4, 5, 6, 7, 8, 9, 10 or 11. 13. At the time of neutralization, 20% by weight based on the total weight.
The following poor solvent is added to make powder, and volatile components are distilled off under reduced pressure.
The production method according to 0, 11 or 12. 14. At the time of neutralization, 10% by weight based on the total weight.
The following poor solvent is added to make powder, and volatile components are distilled off under reduced pressure.
The production method according to 0, 11 or 12. 15. From the stage where the neutralizing agent is uniformly dispersed,
While gradually lowering the peripheral speed of the stirrer blade, finally 90
A method for preventing deterioration (generation of a gelled product due to molecular cutting radicals) of a powder by shearing heat generation by concentrating to dryness under reduced pressure so as to keep the internal temperature at 90 ° C. or lower and m / min or less. 3, 4, 5, 6, 7, 8, 9, 10, 1
The method according to 1, 12, 13 or 14. 16. Alkoxy polyalkylene glycol mono (meth) acrylic acid ester monomer and (meth)
When a cement additive is produced using a monomer containing an acrylic acid-based monomer as a main component, a chain transfer agent and a polymerization initiator, a reactor having a reactor having a lower bearing type agitator is used, and a monomer concentration of 80% by weight is used. %, A method for producing a cement additive characterized by polymerizing. 17. The concentration of monomers to be polymerized is 90% by weight.
The method for producing a cement additive according to claim 16, which is the above. 18. After the completion of polymerization, water is added to dilute the mixture until it has a viscosity such that it can be filled in and taken out from a drum, a lorry or a can, and alkali metal carbonate, alkaline earth metal hydroxide, alkali metal hydroxide or ammonia is added. Alternatively, the method according to claim 16 or 17, wherein neutralization is performed with an amine. 19. The method according to claim 1, 2, 3, 4, 5, 6, 7,
8, 9, 10, 11, 12, 13, 14, 15, 16,
A reactor having a lower bearing type stirrer for use in the method for producing a cement additive according to 17 or 18, which is a reactor having a lower bearing type stirrer, a monomer tank, a polymerization initiator tank, a condenser and a condenser condensate holder. And a monomer tank and a polymerization initiator tank are connected to the reactor having a lower bearing stirrer so that the monomer and the polymerization initiator can be fed through the metering machine to the reactor having a lower bearing stirrer, The condenser is connected to the reactor with the lower bearing type agitator so that the volatile matter from the reactor with the lower bearing type agitator can be cooled / condensed / circulated, and the cooling / condensate from the condenser can be changed by switching the valve. It will collect in the condenser condensate holder A reactor having a reactor having a lower bearing type agitator, characterized in that a pressure control valve is provided in the exhaust line, and the pressure can be controlled to normal pressure, pressurization, or depressurization by switching the valve. . 20. Claims 1, 2, 3, 4, 5, 6, 7,
8, 9, 10, 11, 12, 13, 14, 15, 16,
A reactor having a reactor having a lower-bearing stirrer used in the method for producing the cement additive according to 17 or 18, which is a reactor for initial polymerization having a lower-bearing stirrer, a reactor for aging polymerization having a lower-bearing stirrer, It has a monomer tank, a polymerization initiator tank, a condenser and a condenser condensate holder, so that the monomer tank and the polymerization initiator tank can supply the monomer and the polymerization initiator to an initial polymerization reactor having a lower bearing type agitator. Is connected to an initial polymerization reactor having a lower bearing type agitator, and the initial polymerization reactor having a lower bearing type agitator is a lower bearing type initial polymerization product obtained by the initial polymerization reactor having a lower bearing type agitator. Feeding to a reactor for aging polymerization with stirrer It is connected to cut the initial polymerization, aging both for the polymerization condenser is cooled and condensed and the volatiles from the reactor having a lower bearing stirrers
It is connected to a reactor with a lower bearing type stirrer so that it can recirculate, and it is connected to the condenser so that the cooling / condensate from the condenser accumulates in the condenser condensate holder for both initial polymerization and aging polymerization by switching the valve. A reactor having a lower bearing type stirrer characterized in that a pressure control valve is provided in an exhaust line and can be controlled to normal pressure, pressurization, and depressurization by switching valves. 21. A stirrer for a reactor having a lower bearing type stirrer is provided with horizontal blades that are substantially in contact with the bottom surface, rising blades that are present at both ends of the horizontal blades and that are substantially in contact with the wall surface, and in the middle of the reactor (the middle of the top surface and the bottom surface). There are horizontal blades and falling blades existing on the horizontal blades, and the horizontal blades that are almost in contact with the bottom surface are knife blades so as to scrape up the substances that adhere to and deposit on the bottom surface. Exists,
The rising blades that are almost in contact with the wall surface are knife blades to scrape off the substances adhering to the side surfaces, and the horizontal blades that are present in the middle of the reactor are designed to hold down the substances at the bottom. 20. The blades descending from the horizontal blades are adapted to crush the agglomerates.
Or the reaction device according to 20. 22. The reactor according to claim 21, wherein each of the knife blades is processed into a comb shape.