JP2012149186A - Polyalkylene glycol, method for producing the same, and its application - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyalkylene glycol excellent in silica-based scale preventive effect and the like.SOLUTION: The polyalkylene glycol is represented by formula (1), wherein: Rdenotes a 1-20C organic group; Rare identical or different, and denote a 2-20C alkylene group; Rdenotes a hydrogen atom or a 1-20C organic group; and n is an average addition molar number of an oxyalkylene group, and is the number of 1 to 300.

Description

  The present invention relates to a polyalkylene glycol. More specifically, the present invention relates to a polyalkylene glycol having an excellent silica-based scale prevention effect.

  Corrosion and scale failure occur on water such as cooling water, boiler water, geothermal water, and washing water, and on metal surfaces that contact water, especially heat transfer surfaces. In particular, in an open circulation type cooling water system, from the standpoint of resource and energy saving, when discharging the cooling water out of the system (blowing) and performing high concentration operation, the dissolved salts become highly concentrated and become corrosive. At the same time, scales such as calcium salt, magnesium salt, and silica are generated. Conventionally, various polymers have been proposed as scale inhibitors for preventing or removing these scales.

  For example, in Patent Document 1, (poly) amidoamine obtained by condensing (poly) alkylenepolyamine with dicarboxylic acid, hydrochloride or quaternary ammonium salt of secondary amine moiety of (poly) amidoamine, represented by the general formula (R-1) A polyamidoamine alkylene oxide adduct, a polyamidoamine partially alkylated alkylene oxide adduct, a (poly) alkylene polyamine represented by the general formula (R-2), partially amidated with a monocarboxylic acid, and A scale inhibitor comprising the alkylene oxide adduct and a hydrochloride of a secondary or tertiary amine moiety of a compound represented by the general formula (R-1) or (R-2) or a quaternary ammonium salt is disclosed. Has been.

[Wherein, R ¹ is a dicarboxylic acid residue having 1 to 100 carbon atoms, X ¹ is a (poly) oxyalkylene group represented by — (R ² O) _p —Z, a hydrogen atom, or 1 to 8 carbon atoms. And at least one is a (poly) oxyalkylene group represented by — (R ² O) _p —Z. R ² is an alkylene group having 2 to 8 carbon atoms, Z is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and p is an integer of 1 to 500. M is an integer of 1 to 100, and n is an integer of 1 to 100. ]

[Wherein, X ² is an acyl group represented by R ³ —CO—, a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or (poly) oxyalkylene represented by — (R ² O) _p —Z. And at least one is an acyl group represented by R ³ —CO—. R ³ is an alkyl group having 1 to 30 carbon atoms, R ² is an alkylene group having 2 to 8 carbon atoms, Z is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and p is an integer of 1 to 500. is there. m is an integer of 1-100. ]
For example, Patent Document 2 includes (a) a structural unit having a carboxylic acid group and (b) a structural unit having a polyalkylene oxide group as a repeating structural unit, and has a weight average molecular weight of more than 50,000 and not more than 3 million. It is disclosed that a water-soluble copolymer (salt) can control the adhesion problem of silica-based scales. Examples of the copolymer (salt) of acrylic acid and methoxypolyethylene glycol monomethacrylate are disclosed. Is specifically disclosed.

  For example, Patent Document 3 discloses a scale inhibitor comprising an alkylene oxide adduct of a compound having 3 or more active hydrogen atom-containing groups. In the Examples, a heavy weight obtained by adding ethylene oxide or propylene oxide to sorbitol is disclosed. A merger or the like is specifically disclosed.

  For example, in Patent Document 4, (a) (meth) acrylic acid (salt), (b) sulfonic acid group-containing monomer, (c) N-2-hydroxyethyl (meth) acrylamide, N-vinylpyrrolidone, And a water-soluble copolymer obtained by copolymerizing at least one monomer selected from the group consisting of N-vinyl-ε-caprolactam has good adsorption performance with respect to scale. Therefore, it is disclosed that a very excellent scale prevention effect is exhibited with respect to the generation of silica-based scale.

  However, the silica-based scale preventing effect of conventional polymers is not always satisfactory.

JP 11-138193 A JP 2000-24691 A JP 2006-150180 A JP 2009-51883 A

  An object of the present invention is to provide a polyalkylene glycol excellent in a silica-based scale preventing effect and the like.

  The polyalkylene glycol of the present invention is a polyalkylene glycol represented by the following general formula (1).

In the formula, R ₀ represents an organic group having 1 to 20 carbon atoms, R ₁ is the same or different and represents an alkylene group having 2 to 20 carbon atoms, and R ₂ represents a hydrogen atom or 1 to 20 carbon atoms. N represents the average number of added moles of the oxyalkylene group, and represents a number of 1 to 300.

  According to another aspect of the present invention, a method for producing a polyalkylene glycol is provided. The method for producing a polyalkylene glycol of the present invention comprises a step of reacting a compound having a structural unit represented by the following structural formula (2) and a hydroxyl group with an alkylene oxide having 2 to 20 carbon atoms. This is a method for producing a polyalkylene glycol represented by the general formula (3).

In the formula, R ₀ represents an organic group having 1 to 20 carbon atoms, R ₁ is the same or different and represents an alkylene group having 2 to 20 carbon atoms, and n is an average added mole number of an oxyalkylene group. And represents a number from 1 to 300.
According to another aspect of the present invention, a scale inhibitor is provided. The scale inhibitor of the present invention is a scale inhibitor containing the polyalkylene glycol represented by the general formula (1).
According to another aspect of the invention, a detergent composition is provided. The detergent composition of the present invention is a detergent composition containing a polyalkylene glycol represented by the above general formula (1).
According to another aspect of the present invention, a pigment dispersant is provided. The pigment dispersant of the present invention is a pigment dispersant containing polyalkylene glycol represented by the general formula (1).

ADVANTAGE OF THE INVENTION According to this invention, the polyalkylene glycol excellent in the silica type scale prevention effect etc. can be provided. Moreover, according to this invention, the manufacturing method which can manufacture simply the polyalkylene glycol which has a favorable silica type scale prevention effect can be provided.

1 is a ¹ HNMR chart of a polyalkylene glycol produced in Example 1.

[Polyalkylene glycol]
The polyalkylene glycol of the present invention has a structure represented by the following general formula (1).

In the formula, R ₀ represents an organic group having 1 to 20 carbon atoms, R ₁ is the same or different and represents an alkylene group having 2 to 20 carbon atoms, and R ₂ represents a hydrogen atom or 1 to 20 carbon atoms. N represents the average number of added moles of the oxyalkylene group, and represents a number of 1 to 300.

R ₀ in the general formula (1) represents an organic group having 1 to 20 carbon atoms, and the organic group may include an ester bond, an amide bond, an ether bond, a urethane bond, etc. If it is C1-C20, you may include substituents, such as an alkyl group, an aryl group, an alkoxy group, a hydroxyl group, a carboxyl group, a sulfonic acid group, an acyl group, an amino group. Preferably it is a C1-C4 organic group. Specific examples include alkylene groups such as a methylene group, an ethylene group, a propylene group, and a butylene group, and an ethylene group (—CH ₂ CH ₂ —) is particularly preferable.

R ₁ in the general formula (1) represents an alkylene group having 2 to 20 carbon atoms, and examples thereof include an ethylene group, a propylene group, a butylene group, and an octylene group. R ₁ is preferably an alkylene group having 2 to 8 carbon atoms, more preferably an alkylene group having 2 to 4 carbon atoms, since the silica-based scale preventing effect of polyalkylene glycol is improved. Particularly preferred is an alkylene group having a number of 2 to 3. As the R _1, in which only one may be present alone, or two or more may be mixed.
The group formed by the oxyalkylene group in the general formula (1) (that is, (—O—R ₁ —) _n ) is mainly composed of an oxyethylene group (—O—CH ₂ —CH ₂ —). Preferably there is. In this case, “mainly composed of oxyethylene groups” means that oxyethylene groups account for more than half of the total number of oxyalkylene groups present. As a result, a better scale prevention effect can be obtained. In (—O—R ₁ —) _n in the above general formula (1), “mainly composed of oxyethylene groups” is expressed as 50% by mol% of oxyethylene groups in 100 mol% of all oxyalkylene groups. It is preferably ˜100 mol%. When the content of the oxyethylene group is less than 50 mol%, the scale prevention ability (also referred to as scale prevention ability) may be reduced. More preferably, it is 60 mol% or more, more preferably 70 mol% or more, particularly preferably 80 mol% or more, and most preferably 90 mol% or more.

In the general formula (1), n oxyalkylene groups _{(-O-R 1} -) represents an average addition mole number of a number of 1 to 300, preferably from 3 to 150, more preferably 5 It is -100, More preferably, it is 7-60. If it is the said range, favorable scale prevention ability will be acquired.

R ₂ in the general formula (1) represents a hydrogen atom or an organic group having 1 to 20 carbon atoms, and the organic group having 1 to 20 carbon atoms includes an ester bond, an amide bond, an ether bond, a urethane bond, and the like. If the organic group as a whole has 1 to 20 carbon atoms, it may contain a substituent such as an alkyl group, an aryl group, an alkoxy group, a hydroxyl group, a carboxyl group, a sulfonic acid group, an acyl group, and an amino group. . Specific examples include a methyl group, an ethyl group, a propyl group, and a butyl group.
R ₂ is preferably a hydrogen atom or an organic group having 1 to 4 carbon atoms, and particularly preferably a hydrogen atom.

Further, the polyalkylene glycol of the present invention may be a polyalkylene glycol in which a part or all of the hydrogen atoms present in the pyrrolidone ring in the general formula (1) are substituted with other organic groups. Examples of the other substituent in this case include the same groups as those in R ₂ in the general formula (1).

[Production method of polyalkylene glycol]
Since the polyalkylene glycol of the present invention tends to improve the yield, the step of reacting the structural unit represented by the following structural formula (2) and a compound having a hydroxyl group with an alkylene oxide having 2 to 20 carbon atoms. (It is preferable to manufacture by the method which makes a process (1) essential.

By the above reaction, a compound represented by the following general formula (3) is obtained.

In the formula, R ₀ represents an organic group having 1 to 20 carbon atoms, R ₁ is the same or different and represents an alkylene group having 2 to 20 carbon atoms, and n is an average added mole number of an oxyalkylene group. And represents a number from 1 to 300.
The compound represented by the general formula (3) may be further modified by reacting the terminal hydroxyl group with an alkyl halide, an acid anhydride or the like.

The compound having the structural unit represented by the structural formula (2) and the hydroxyl group is not particularly limited, but a method of reacting γ-butyrolactones and amino alcohols is preferable. For example, JP-A-2002-167375 It can be produced by the disclosed method.
Examples of the compound having a structural unit represented by the structural formula (2) and a hydroxyl group include N-hydroxyethylpyrrolidone, N-hydroxypropylpyrrolidone, N-hydroxybutylpyrrolidone and the like.

  The polyalkylene glycol of the present invention may be produced by a method that does not include the step (1). For example, (i) a compound having a structural unit represented by the above structural formula (2) and a hydroxyl group, and (ii) a reaction capable of reacting with a polyalkylene glycol chain and a hydroxyl group such as an isocyanate group, an epoxy group, an ester group or an amide group. You may manufacture by making the compound which has a sex group react.

(Process (1))
Step (1) includes, as described above, (i) a compound having a structural unit represented by the above structural formula (2) and a hydroxyl group (hereinafter also referred to as compound A), and (ii) an alkylene having 2 to 20 carbon atoms. This is a step of reacting an oxide.
In the step (1), the compound A and the alkylene oxide are reacted without a catalyst or in the presence of a catalyst. From the viewpoint of the reaction rate, the step (1) is preferably performed in the presence of a catalyst. A preferred catalyst is an acid catalyst or a basic catalyst.

  Examples of the acid catalyst include mineral acids such as sulfuric acid and phosphoric acid, and Lewis acids such as tin tetrachloride and boron trifluoride. Among them, tin tetrachloride, antimony pentachloride, boron trifluoride, or a complex thereof, This is preferable because the scale preventing ability of polyalkylene glycol is improved. As the basic catalyst, sodium hydroxide and potassium hydroxide are preferable.

The step (1), as the reaction pressure, 20 Kg / ^cm 2 G from atmospheric pressure, preferably 1~10Kg / cm ² G. The reaction temperature is preferably 20 to 180 ° C, more preferably 30 to 160 ° C.

The step (1) is usually a step (1-1) of charging the compound A into the reactor, a step (1-2) of adding alkylene oxide to the reactor, and a step of reacting the compound A and alkylene oxide (1). -3).
Preferably, the method further includes a step (1-4) of adding a reaction catalyst. By including the process of (1-4), since reaction efficiency improves and an impurity can be reduced, the scale prevention ability of the polyalkylene glycol obtained improves.
Furthermore, a step (A-5) for removing impurities such as moisture may be provided before or during the step (1-2) or (1-3), preferably after the step (1-4). .
The process (1-2) and the process (1-3) may be started at the same time, or the process (1-3) may be started after the process (1-2). It is preferable to continue the process (1-3) after the process (2) is completed (that is, the process (1-3) is completed later than the process (1-2)). By performing all or part of the step (1-3) after the step (1-2), the polyalkylene glycol can be efficiently produced.
Moreover, it is preferable to perform a process (1-4) before the process of (1-2) and the process of (1-3).

The step (1) is usually preferably performed in an atmosphere of an inert gas such as nitrogen gas. Moreover, you may preserve | save in the atmosphere of inert gas, such as nitrogen gas, after reaction.
The step (1) is preferably carried out without a solvent, but a solvent may be used. When a solvent is used, those capable of dissolving Compound A and alkylene oxide are preferred.

  In the above step (1), it is preferable that Compound A is charged in advance into the reactor (initial charge). By initially charging, the distribution of the number of added moles is narrowed, and for example, the dispersion performance of inorganic particles is improved. On the other hand, the entire amount of alkylene oxide may be added, but it is preferable to gradually add it to the reactor after the start of the reaction. When adding gradually, a batch type or a continuous type may be sufficient.

  Note that the step (1) can be further divided into a plurality of steps. For example, a step of adding a small amount of alkylene oxide to Compound A and a step of further adding alkylene oxide to the polyalkylene glycol obtained by the step may be provided, and alkylene oxide may be added in two steps or three or more steps. good.

  There may be a step of removing the catalyst in the reaction solution after or during the step (1). For example, when the polyalkylene glycol in the course of the reaction is insoluble in water, it is allowed to stand after washing with water or the like, and the organic layer and the aqueous layer can be separated to remove the catalyst. The said washing | cleaning can be performed at 20-150 degreeC with a stirring tank and a line mixer, for example.

In the production method of the polyalkylene glycol of the present invention, a purification step may be provided after or in the middle of the step (1) other reaction step, if necessary. Examples of the purification step include a step of removing residual raw materials, by-products, moisture, catalyst residues, and the like, a step of neutralizing the catalyst, and the like.
As the step of neutralizing the catalyst, for example, when the reaction is carried out in the presence of sodium hydroxide and / or potassium hydroxide, a solid acid such as sulfuric acid, acetic acid or activated clay is used as the neutralizing agent at that time. Can do.

[Polyalkylene glycol composition]
The polyalkylene glycol composition of the present invention is characterized by containing the polyalkylene glycol of the present invention as an essential component. Content of the polyalkylene glycol of this invention is 1-100 mass parts with respect to 100 mass parts of compositions.
The polyalkylene glycol composition of the present invention may contain water in consideration of stability and handleability. The water content is preferably 0 to 50 parts by mass with respect to 100 parts by mass of the composition. . 5-30 mass parts is preferable from the surface of stability improvement.
The polyalkylene glycol composition of the present invention may contain, in addition to the polyalkylene glycol of the present invention and water, raw materials, by-products, catalyst residues, solvents and the like as impurities.

[Use]
The polyalkylene glycol of the present invention can be used as a scale inhibitor, but can be used as an additive such as a pigment dispersant and a fiber treatment agent, a detergent additive, and the like.

<Water treatment agent, scale inhibitor>
The polyalkylene glycol of the present invention can be added to water treatment agents and scale inhibitors. For the water treatment agent and the like, an anticorrosive agent, a slime control agent, and a chelating agent may be used as other compounding agents as necessary. Anticorrosive agents include phosphates, polymerized phosphates, phosphate esters, phosphonates, polyvalent metals such as zinc, aluminum and nickel, azoles such as benzotriazole, tolyltriazole and mercaptobenzothiazole, hydrazine, etc. Is mentioned. Examples of the slime control agent include quaternary ammonium salts such as alkyldimethylbenzylammonium chloride, chloromethyltrithiazoline, methylisothiazoline, and ethylaminoisopropylaminomethylthiotriazine.

  The above-mentioned water treatment agent and the like are useful for preventing scale in a cooling water circulation system, a boiler water circulation system, a seawater desalination apparatus, a pulp digester, a black liquor concentration tank, a steel dust collecting water system, a geothermal water system, and the like. It is particularly useful as a silica-based scale inhibitor. Examples of the aqueous system in which the scale inhibitor of the present invention sufficiently exhibits the effect include a high salt aqueous system, particularly a high silica concentration aqueous system having a silica concentration of 150 mg / L or more.

  The water treatment agent may contain any appropriate water-soluble polymer as long as the performance and effects are not affected. Suitable water-soluble polymers include carboxyl group-containing monomers such as acrylic acid and maleic acid, styrene sulfonic acid, allyl sulfonic acid, methallyl sulfonic acid, 2-hydroxy-3-allyloxypropane sulfonic acid, 2- Examples of the present invention include copolymers and / or homopolymers obtained by polymerizing sulfonic acid group-containing monomers such as hydroxy-3-methallyloxypropanesulfonic acid and isoprenesulfonic acid, and salts thereof as essential components. The water treatment agent in is effective even if the polyalkylene glycol of the present invention alone is used, but the effect is further exhibited by the combined use with the appropriate water-soluble polymer. These two types of polymers may be mixed in advance at a predetermined ratio, or may be separately injected into the target water system. The amount added varies depending on the water quality of the target aqueous system, but is preferably about 1 to 200 mg / L as a standard. When the polyalkylene glycol of the present invention and the appropriate water-soluble polymer are used in combination, the ratio is preferably 99/1 to 10/90 mass ratio.

  The water treatment agent may be in the form of a solid such as a powder or a liquid.

<Inorganic pigment dispersant>
The polyalkylene glycol of the present invention can be added to an inorganic pigment dispersant. In the inorganic pigment dispersant, condensed phosphoric acid and its salt, phosphonic acid and its salt, and polyvinyl alcohol may be used as other compounding agents as required.

  The content of the polyalkylene glycol of the present invention in the inorganic pigment dispersant is preferably 5 to 100% by weight with respect to the whole inorganic pigment dispersant. Further, any appropriate water-soluble polymer may be included as long as it does not affect the performance and effect. The inorganic pigment dispersant may be either solid, such as powder, or liquid.

  The inorganic pigment dispersant can exhibit good performance as a dispersant for carbon black, for example. For example, by adding a small amount of an inorganic pigment dispersant to an inorganic pigment and dispersing it in water, a high-concentration carbon black that has low viscosity and high fluidity and good aging stability of their performance. High concentration inorganic pigment slurries such as slurries can be produced.

  When the inorganic pigment dispersant is used as a dispersant for an inorganic pigment, the amount of the inorganic pigment dispersant used is preferably 0.05 to 2.0 parts by weight with respect to 100 parts by weight of the inorganic pigment. When the amount of the inorganic pigment dispersant used is within the above range, a sufficient dispersion effect can be obtained, and an effect commensurate with the addition amount can be obtained, which can be economically advantageous.

<Fiber treatment agent>
The polyalkylene glycol of the present invention can be added to a fiber treatment agent. The fiber treatment agent includes at least one selected from the group consisting of a dye, a peroxide and a surfactant, and the polyalkylene glycol of the present invention.

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

  Below, the compounding example of the fiber processing agent which is closer to embodiment is shown. This fiber treatment agent can be used in the steps of refining, dyeing, bleaching and soaping in fiber treatment. Examples of dyeing agents, peroxides and surfactants include those usually used for fiber treatment agents.

  The blending ratio of the polyalkylene glycol of the present invention to at least one selected from the group consisting of a dye, a peroxide and a surfactant is, for example, for improving the whiteness, color unevenness and dyeing tempering of the fiber. In the amount of pure fiber treatment agent, 0.1 to 100 at least one selected from the group consisting of a dye, a peroxide and a surfactant is added to 1 part by weight of the polymer composition of the present invention. It is preferable to use the composition mix | blended in the ratio of the weight part as a fiber processing agent.

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

When the fiber treatment agent is applied to the refining process, it is preferable to blend the amino acid (salt) composition of the present invention with an alkali agent and a surfactant. When applied to the bleaching step, it is preferable to blend the polyalkylene glycol of the present invention, a peroxide, and a silicic acid-based agent such as sodium silicate as a decomposition inhibitor for the alkaline bleaching agent.
The surfactant is one or more selected from the group consisting of an anionic surfactant, a nonionic surfactant, a cationic surfactant and an amphoteric surfactant. When two or more kinds are used in combination, the total amount of the anionic surfactant and the nonionic surfactant is preferably 50% by mass or more, more preferably 60% by mass with respect to the total amount of the surfactant. It is above, More preferably, it is 70 mass% or more, Most preferably, it is 80 mass% or more.
The fiber treatment agent may be in a solid form such as a powder form or in a liquid form.

<Detergent composition>
The polyalkylene glycols of the present invention can also be added to detergent compositions.

  The content of the polyalkylene glycol in the detergent composition is not particularly limited. However, from the viewpoint of exhibiting excellent builder performance, the content of polyalkylene glycol is preferably 0.1 to 15% by mass, more preferably 0.3%, based on the total amount of the detergent composition. It is 10 mass%, More preferably, it is 0.5-5 mass%.

  Detergent compositions used in detergent applications usually include surfactants and additives used in detergents. Specific forms of these surfactants and additives are not particularly limited, and conventionally known knowledge can be appropriately referred to in the detergent field. The detergent composition may be a powder detergent composition or a liquid detergent composition.

  The surfactant is one or more selected from the group consisting of an anionic surfactant, a nonionic surfactant, a cationic surfactant and an amphoteric surfactant. When two or more kinds are used in combination, the total amount of the anionic surfactant and the nonionic surfactant is preferably 50% by mass or more, more preferably 60% by mass with respect to the total amount of the surfactant. It is above, More preferably, it is 70 mass% or more, Most preferably, it is 80 mass% or more.

  Additives include anti-redeposition agents to prevent redeposition of contaminants such as alkali builders, chelate builders, sodium carboxymethylcellulose, stain inhibitors such as benzotriazole and ethylene-thiourea, soil release agents, and color transfer. Inhibitors, softeners, alkaline substances for pH adjustment, fragrances, solubilizers, fluorescent agents, colorants, foaming agents, foam stabilizers, polishes, bactericides, bleaching agents, bleaching aids, enzymes, dyes A solvent or the like is preferable. In the case of a powder detergent composition, it is preferable to blend zeolite.

  In addition, the concept of the above-mentioned detergent composition includes specific detergents such as synthetic detergents for household detergents, textile industry and other industrial detergents, hard surface cleaners, and bleaching detergents that enhance one of the components. Also included are detergents that are only used.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these Examples. Unless otherwise specified, parts and% in the examples are based on mass.

(Measurement of solid content)
In an oven heated to 130 ° C. in a nitrogen atmosphere, 1.0 g of polyalkylene glycol (composition) +3.0 g of water was left for 1 hour for drying treatment. From the weight change before and after drying, the solid content (%) and the volatile component (%) were calculated.

(Measurement conditions for polyalkylene glycol)
The polyalkylene glycol of the present invention was measured using high performance liquid chromatography.
Measuring device: 8020 series manufactured by Tosoh Corporation Column: CAPCELL PAK C1 UG120 manufactured by Shiseido Co., Ltd.
Temperature: 40.0 ° C
Eluent: 10 mmol / L Disodium hydrogen phosphate.12 hydrate aqueous solution (adjusted to pH 7 with phosphoric acid) / acetonitrile = 45/55 (volume ratio)
Flow rate: 1.0 ml / min
Detector: RI, UV (detection wavelength 215 nm)
(Method for evaluating silica-based scale prevention (silica-based scale prevention ability))
(1) 200 mg / L MgSO ₄ · 7H ₂ O in ion-exchanged water (in terms of CaCO ₃ ) and the scale inhibitor described in Table 1 are added to 100 ppm, and Na ₂ SiO ₃ · 9H ₂ 210 mg / L of O (converted to SiO ₂ ) and 500 mg / L of NaHCO ₃ (converted to CaCO ₃ ) were added. After adjusting the pH of this solution to 9.00 ± 0.1, the solution was allowed to stand at 70 ° C. for 40 hours (also referred to as a post-heat treatment solution). Further, only Na ₂ SiO ₃ .9H ₂ O was prepared to 210 mg / L (converted to SiO ₂ ) with ion-exchanged water (referred to as non-heat-treated liquid).
Thereafter, the heat treatment liquid was filtered through a 0.1 μ filter. The filtrate was diluted 10 times with pure water, and the Si concentration was measured using an ICP emission spectrophotometer (ICPE-9000, manufactured by Shimadzu). The 10 times this value was taken as the Si concentration in the filtrate, and the Si concentration Was converted to SiO ₂ concentration. Si deposition amount (Amg / L, SiO ₂ conversion) was calculated as follows.
Si deposition amount (Amg / L, SiO ₂ in terms of) a SiO ₂ concentration of = unheated liquid - except without the addition of scale inhibitor in the SiO ₂ concentration in the heat-treated solution (2) above (1) similar to (1) was calculated Si deposition amount of the blank (Bmg / L, SiO ₂ conversion) on to.
(3) The silica-based scale preventing ability was calculated as follows.
Silica-based scale prevention ability (%) = (B−A) / B × 100
The results are shown in Table 1. In the case SiO ₂ concentration in the filtrate is high, indicates that Si components not scaled often, i.e., indicating that the scale prevention is good. Therefore, the higher the silica-based scale prevention ability (%), the better the scale prevention ability.

Example 1
In a SUS autoclave reaction vessel equipped with a thermometer, a stirrer, a raw material introduction tube and a nitrogen introduction tube, N-hydroxyethylpyrrolidone (hereinafter sometimes referred to as HEP) 374.6 g (2.9 mol), reaction catalyst As a solution, 0.33 g (200 ppm) of sodium hydroxide was charged, and the reaction vessel was purged with nitrogen under stirring, and heated to 120 ° C. in a nitrogen atmosphere. Then, 1281.8 g (29.0 mol) of ethylene oxide was introduced into the reactor over 3.5 hours while maintaining 120 ± 5 ° C. under safe pressure, and the temperature was maintained for another 2 hours after the introduction. Finally, the inside of the reaction vessel was purged with nitrogen under stirring and cooled to room temperature. Thus, polyalkylene glycol (1) in which an average of 10 moles of ethylene oxide was added to HEP was obtained.

(Example 2)
600 g of polyalkylene glycol in which an average of 10 mol of ethylene oxide was added to HEP produced in the same manner as in Example 1 above in a SUS autoclave reaction vessel equipped with a thermometer, a stirrer, a raw material introduction tube and a nitrogen introduction tube ( 1.1 mol), the reaction vessel was purged with nitrogen under stirring, and heated to 120 ° C. in a nitrogen atmosphere. Then, 195.1 g (4.4 mol) of ethylene oxide was introduced into the reactor over 2.5 hours while maintaining 120 ± 5 ° C. under safe pressure, and the temperature was maintained for another 1.5 hours after the introduction. Finally, the inside of the reaction vessel was purged with nitrogen under stirring and cooled to room temperature. In this way, polyalkylene glycol (2) in which 14.2 moles of ethylene oxide was added to HEP on average was obtained.

(Example 3)
Polyalkylene glycol in which 14.2 moles of average ethylene oxide was added to HEP produced in the same manner as in Example 2 above in a SUS autoclave reaction vessel equipped with a thermometer, stirrer, raw material introduction tube and nitrogen introduction tube 780.7 g (1.1 mol) was charged, the inside of the reaction vessel was purged with nitrogen under stirring, and heated to 120 ° C. in a nitrogen atmosphere. Then, 284.2 g (6.5 mol) of ethylene oxide was introduced into the reactor over 5.3 hours while maintaining 120 ± 5 ° C. under safe pressure, and the temperature was maintained for another 4.2 hours after the introduction. Finally, the inside of the reaction vessel was purged with nitrogen under stirring and cooled to room temperature. Thus, polyalkylene glycol (3) in which 20.4 moles of ethylene oxide was added to HEP on average was obtained.

Example 4
The polyalkylene glycols (1) and (2) obtained in the above-mentioned Examples, and the silica-based scale preventing ability of sodium polyacrylate having a weight average molecular weight of 5000, which is a representative scale inhibitor as the comparative polymer (1). It measured according to the said evaluation method. The measurement results are shown in Table 1.

It has been clarified that the polyalkylene glycol of the present invention exhibits better silica-based scale prevention properties than conventional polyalkylene glycols.

  The polyalkylene glycol of the present invention has a good scale preventing ability. Therefore, particularly excellent performance can be exhibited when used in water treatment applications such as scale inhibitors, detergent additives, and pigment dispersants.

Claims (5)

Polyalkylene glycol represented by the following general formula (1).

In the formula, R ₀ represents an organic group having 1 to 20 carbon atoms, R ₁ is the same or different and represents an alkylene group having 2 to 20 carbon atoms, and R ₂ represents a hydrogen atom or 1 to 20 carbon atoms. N represents the average number of added moles of the oxyalkylene group, and represents a number of 1 to 300. The structural unit represented by the following structural formula (2) and a hydroxyl group-containing compound and a C2-C20 alkylene oxide are essentially required to be reacted, which is represented by the general formula (3). A method for producing polyalkylene glycol.

In the formula, R ₀ represents an organic group having 1 to 20 carbon atoms, R ₁ is the same or different and represents an alkylene group having 2 to 20 carbon atoms, and n is an average added mole number of an oxyalkylene group. And represents a number from 1 to 300. A scale inhibitor comprising the polyalkylene glycol according to claim 1. A detergent composition comprising the polyalkylene glycol according to claim 1. A pigment dispersant comprising the polyalkylene glycol according to claim 1.

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