Solution, dispersant, method for producing vinyl compound polymer, and method for producing solution

Abstract

Provided are: a solution which has high stability regardless of the alcohol content and has excellent performance as a dispersant for suspension polymerization; a method for producing the solution; and the like. A solution containing a vinyl alcohol polymer (A) having a degree of saponification of 30-80 mol% and a degree of polymerization of 100-700, a compound (B) represented by formula (1), and an alcohol (C). In formula (1), X is an oxygen atom or the like. And Y is a group with 1-10 carbon atoms. And Z is one selected from the group consisting of a carboxyl group, a sulfo group, a phosphate group, salts thereof, and anions thereof. R1 is acyl or alkyl.

Description

Technical Field

[0001] This invention relates to methods for manufacturing solutions, dispersants, vinyl compound polymers, and solutions. Background Technology

[0002] Vinyl alcohol polymers (hereinafter also referred to as "PVA") are known as water-soluble synthetic polymers. PVA is used in a variety of applications, including as a raw material for membranes and fibers, an additive for paper and fiber processing, an adhesive, a dispersant (also known as a dispersion stabilizer, etc.) for emulsion polymerization and suspension polymerization, and a binder for inorganic materials.

[0003] PVA is sometimes stored, distributed, sold, and used in solution form. Generally, the solubility of PVA in water and other substances varies depending on the degree of saponification, degree of polymerization, and the introduced modifiers. When storing and using PVA in solution form, especially from the viewpoint of productivity and processability, high-concentration, low-viscosity, and highly stable solutions are required. Here, it is known in the prior art that even PVA, which is insoluble in water on its own, can become soluble in water by combining it with specific surfactants (see Patent Document 1).

[0004] Existing technical documents Patent documents Patent Document 1: Japanese Patent Application Publication No. 53-133252. Summary of the Invention

[0005] The problem that the invention aims to solve By using specific surfactants, the solubility of PVA can be improved as described above, thereby enhancing the stability of the resulting solution. However, due to the influence of surfactants, it is impossible to produce a solution with excellent stability and properties as a dispersant for suspension polymerization. On the other hand, according to the inventors' understanding, even without using surfactants, it is possible to prepare a PVA solution with high stability and good performance as a dispersant for suspension polymerization by using a solvent with a high alcohol content. However, solutions containing solvents with a high alcohol content are sometimes limited in their processing form due to wastewater treatment, environmental impact, etc.

[0006] One of the objectives of this invention is to provide a solution that exhibits high stability regardless of the alcohol content and performs excellently as a dispersant for suspension polymerization, as well as a method for manufacturing such a solution.

[0007] In addition, another object of the present invention is to provide a dispersant with excellent performance as a dispersant for suspension polymerization, and a method for manufacturing vinyl compound polymers using such a dispersant.

[0008] means for solving problems The above objectives are achieved by providing the following solutions.

[0009] [1] A solution comprising a vinyl alcohol polymer (A), a compound (B), and an alcohol (C), wherein the vinyl alcohol polymer (A) has a saponification degree of 30 mol% or more and 80 mol% or less, and a polymerization degree of 100 or more and 700 or less. Compound (B) is the compound represented by the following formula (1); [Chemistry 1] (In formula (1), X is an oxygen atom, a group shown in formula (2) below, or a group shown in formula (3) below. Y is a group with 1 to 10 carbon atoms. Z is one selected from carboxyl, sulfonyl, phosphate, their salts, and their anions. R) 1 It can be an acyl or hydrocarbon group. [Chemistry 2] [Chemistry 3] (In equations (2) and (3), R) 2 R 3 and R 4 Each is independently a hydrogen atom, an alkyl group with 1 to 3 carbon atoms, or a linking bond to Y. * indicates a linking bond. [2] According to the solution of [1], the block character of the vinyl ester unit in the vinyl alcohol polymer (A) is 0.4 or more and 0.6 or less; [3] According to the solution of [1] or [2], the content of the vinyl alcohol polymer (A) is 15% by mass or more; [4] According to any one of [1] to [3], the content of compound (B) is 0.5% by mass or more and 10% by mass or less; [5] According to any one of [1] to [4], the content of alcohol (C) is more than 5% by mass and less than 80% by mass; [6] According to any one of [1] to [5], the content of alcohol (C) is less than 20% by mass% in the solution. [7] According to any one of [1] to [6], wherein the content of compound (B) is 0.5% by mass or more and 4% by mass or less, and the content of alcohol (C) is 5% by mass or more and 15% by mass or less; [8] A dispersant comprising a vinyl alcohol polymer (A) and a compound (B), wherein the vinyl alcohol polymer (A) has a saponification degree of 30 mol% or more and 80 mol% or less, and a polymerization degree of 100 or more and 700 or less. Compound (B) is the compound represented by the following formula (1); [Chemistry 4] (In formula (1), X is an oxygen atom, a group shown in formula (2) below, or a group shown in formula (3) below. Y is a group with 1 to 10 carbon atoms. Z is one selected from carboxyl, sulfonyl, phosphate, their salts, and their anions. R) 1 It can be an acyl or hydrocarbon group. [Chemistry 5] [Chemistry 6] (In equations (2) and (3), R) 2 R 3 and R 4 Each is independently a hydrogen atom, an alkyl group with 1 to 3 carbon atoms, or a linking bond to Y. * indicates a linking bond. [9] A method for manufacturing a vinyl compound polymer, comprising: a step of polymerizing a vinyl compound in the presence of a dispersant of [8];

[10] A method for manufacturing a solution comprising: adding a vinyl alcohol polymer (A) to a liquid comprising a compound (B) and an alcohol (C) as shown in formula (1) in multiple steps, wherein the vinyl alcohol polymer (A) has a saponification degree of 30 mol% or more and 80 mol% or less, and a polymerization degree of 100 or more and 700 or less. [Chemistry 7] (In formula (1), X is an oxygen atom, a group shown in formula (2) below, or a group shown in formula (3) below. Y is a group with 1 to 10 carbon atoms. Z is one selected from carboxyl, sulfonyl, phosphate, their salts, and their anions. R) 1 It can be an acyl or hydrocarbon group. [Chemistry 8] [Chemistry 9] (In equations (2) and (3), R) 2 R 3 and R 4 Each is independently a hydrogen atom, an alkyl group with 1 to 3 carbon atoms, or a linking bond to Y. * indicates a linking bond.

[11] The dispersant is a solution of 15% by mass or more of an ethylene alcohol polymer (A) having a saponification degree of 30 mol% or more and 80 mol% or less, a polymerization degree of 100 or more and 700 or less, and a block characteristic of ethylene ester units of 0.6 or less.

[12] According to the dispersant of

[11] , wherein the aforementioned solution contains at least one selected from acids, their salts and anions having an acid dissociation constant (pKa) of 0 or more and 6.0 or less in water;

[13] According to the dispersant of

[11] or

[12] , it is used for the polymerization of vinyl compounds;

[14] A method for manufacturing vinyl compound polymers, comprising: The preparation process involves preparing a vinyl alcohol polymer (A) with a saponification degree of 30 mol% or more and 80 mol% or less, a polymerization degree of 100 or more and 700 or less, and a block characteristic of ethylene ester units of 0.6 or less; and The polymerization process involves polymerizing vinyl compounds in the presence of a vinyl alcohol-based polymer (A) to obtain vinyl compound polymer particles with an average particle size of less than 220 μm. In the aforementioned preparation process, a solution of vinyl alcohol polymer (A) with a concentration of 15% by mass or more is prepared.

[15] The method for manufacturing a vinyl compound polymer according to

[14] , wherein the solution in the aforementioned preparation step comprises at least one selected from an acid, its salt and its anion having an acid dissociation constant (pKa) of 0 or more and 6.0 or less in water;

[16] According to the method for manufacturing vinyl compound polymers according to

[14] or

[15] , wherein, in the aforementioned polymerization step, a solution of the aforementioned vinyl alcohol polymer (A) with a concentration of 15% by mass or more is introduced into the polymerization reaction system of the vinyl compound;

[17] According to the method for manufacturing vinyl compound polymers according to

[14] or

[15] , in the aforementioned polymerization step, a solution of the aforementioned vinyl alcohol polymer (A) with a concentration of 15% by mass or more is diluted and introduced into the polymerization reaction system of the vinyl compound.

[0010] Invention Effects According to the present invention, a solution with high stability regardless of the alcohol content and excellent performance as a dispersant for suspension polymerization can be provided, as well as a method for manufacturing such a solution.

[0011] Furthermore, according to the present invention, a dispersant with excellent performance as a dispersant for suspension polymerization and a method for manufacturing vinyl compound polymers using such a dispersant can be provided. Detailed Implementation

[0012] In this specification, the numerical range recorded using "~" refers to the values ​​recorded before and after "~" as the lower and upper limits.

[0013] <solution> The solution described in one embodiment of the present invention comprises a vinyl alcohol polymer (A) (hereinafter also referred to as "PVA (A)"), a compound (B) and an alcohol (C), wherein the vinyl alcohol polymer (A) has a saponification degree of 30 mol% or more and 80 mol% or less, and a polymerization degree of 100 or more and 700 or less, and the compound (B) is the compound represented by formula (1) described later.

[0014] This solution exhibits high stability regardless of the alcohol (C) content. By adjusting the composition ratio, it is possible to prepare solutions with high PVA (A) concentration, low viscosity, and high stability. This solution is particularly suitable from the viewpoint of productivity and processability. The alcohol (C) content in this solution is not limited; for example, by increasing the alcohol (C) content, a solution with particularly low viscosity can be prepared. On the other hand, by reducing the alcohol (C) content, processability in wastewater treatment and other applications can be improved. Furthermore, this solution performs excellently as a dispersant for suspension polymerization. Specifically, by using this solution as a dispersant in suspension polymerization, polymer particles with a stable average particle size and few coarse particles can be effectively obtained. Additionally, polymer particles obtained through suspension polymerization using this solution as a dispersant also exhibit good plasticizer absorption.

[0015] The reason why this solution exhibits the aforementioned effects is uncertain, but it can be speculated that it is due to the following reasons: It can be speculated that compound (B), by having a defined structure, functions as a good surfactant, maintaining a good dispersion of PVA (A) in the solution, thus improving the stability of the solution. Furthermore, it can be speculated that by including alcohol (C) in the solution, the stability of the solution is improved. Additionally, by giving compound (B) a defined structure, its acid dissociation constant falls within an appropriate range, thereby influencing the aforementioned effects. That is, for example, in a near-neutral environment, the interaction between compound (B) and PVA (A) can improve the dispersion stability of PVA (A). On the other hand, it can be considered that in suspension polymerization systems, which are typically in weakly acidic environments, compound (B) separates from PVA (A), and PVA (A) is less affected by compound (B), thus fully functioning as a dispersant for suspension polymerization.

[0016] In this way, the solution can be suitable as a dispersant when added to the suspension polymerization system during suspension polymerization. Furthermore, since the solution is a liquid, it also has advantages such as not requiring the dissolution of the vinyl alcohol polymer and excellent processability when used as a dispersant in suspension polymerization.

[0017] The solution may also contain other components besides PVA (A), compound (B), and alcohol (C). The components of the solution are described in detail below.

[0018] (PVA(A)) PVA(A) is a polymer having vinyl alcohol units as structural units. PVA(A) is typically obtained by saponifying vinyl ester polymers. PVA(A) is a type of PVA with a saponification degree of 30 mol% or more and 80 mol% or less, and a polymerization degree of 100 or more and 700 or less. PVA(A) with such a degree of saponification and polymerization typically has low solubility in water, and when a solution is obtained, its stability is also low, and it is prone to gelation, precipitation, etc. In one embodiment of the present invention, the solution contains compound (B) and alcohol (C), therefore, despite containing this type of PVA(A), the stability of the solution remains high.

[0019] The lower limit of the degree of saponification of PVA(A) is 30 mol%, which can be 32 mol% or 34 mol%. The upper limit of the degree of saponification of PVA(A) is 80 mol%, which can be 70 mol%, 60 mol%, 50 mol%, 45 mol%, or 40 mol%. When the degree of saponification of PVA(A) is within the above range, the surface activation energy can be optimized, thereby improving its performance as a dispersant for suspension polymerization. The degree of saponification is measured by the method described in JIS K6726:1994.

[0020] The lower limit of the degree of polymerization of PVA(A) is 100, but it can be 130, 160, 190, or 210. By setting the degree of polymerization above this lower limit, the protective colloidal properties are improved, and when used as a dispersant for suspension polymerization, smaller polymer particles can be produced. On the other hand, the upper limit of this degree of polymerization is 700, but it can be 600, 500, 400, or 300. By setting the degree of polymerization below this upper limit, the surface activation energy is increased, and when used as a dispersant for suspension polymerization, the plasticizer absorption capacity of the resulting polymer particles is improved, and smaller polymer particles can be produced. Furthermore, by setting the degree of polymerization below the upper limit, there is a tendency for the solution to become less viscous. It should be noted that the degree of polymerization of PVA(A) refers to the viscosity-average degree of polymerization measured according to JIS K6726:1994.

[0021] PVA(A) may have structural units other than vinyl alcohol units and vinyl ester units (hereinafter also referred to as "residual vinyl ester units"). Monomers providing these other structural units include α-olefins such as ethylene, propylene, 1-butene, isobutene, and 1-hexene; acrylic acid and methacrylic acid; acrylates such as methyl acrylate and ethyl acrylate; methacrylates such as methyl methacrylate and ethyl methacrylate; acrylamide derivatives such as N-methacrylamide and N-ethylacrylamide; methacrylamide derivatives such as N-methylmethacrylamide and N-ethylmethacrylamide; vinyl ethers such as methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, isopropyl vinyl ether, and n-butyl vinyl ether; and vinyl ethers containing hydroxyl groups such as ethylene glycol vinyl ether, 1,3-propanediol vinyl ether, and 1,4-butanediol vinyl ether. Ethers; allyl acetate; allyl ethers such as propyl allyl ether, butyl allyl ether, and hexyl allyl ether; monomers containing oxyalkylene groups; isopropyl acetate; α-olefins containing hydroxyl groups such as 3-buten-1-ol, 4-penten-1-ol, 5-hexen-1-ol, 7-octen-1-ol, 9-decen-1-ol, and 3-methyl-3-buten-1-ol; monomers containing silyl groups such as vinyltrimethoxysilane, vinylmethyldimethoxysilane, vinyldimethylmethoxysilane, vinyltriethoxysilane, vinylmethyldiethoxysilane, vinyldimethylethoxysilane, 3-(meth)acrylamidopropyltrimethoxysilane, and 3-(meth)acrylamidopropyltriethoxysilane. Among these, α-olefins, acrylic acid, methacrylic acid, acrylates, or methacrylates are preferred. In addition, in one embodiment of the present invention, PVA(A) preferably does not have polyoxyethylene side chains; in other embodiments, PVA(A) preferably does not contain structural units derived from monomers having oxyalkylene groups.

[0022] The proportion of the aforementioned other structural units in all structural units of PVA(A) is sometimes preferably 20 mol% or less, and more preferably 15 mol% or less, 10 mol% or less, 5 mol% or less, or 1 mol% or less. On the other hand, the proportion of the aforementioned other structural units may be, for example, 0.1 mol% or more, or 1 mol% or more.

[0023] As PVA(A), a material that has not been graft copolymerized is preferred. PVA(A) can be a material modified using one or more graftable comonomers. Graft copolymerization can be performed on at least one of a vinyl ester polymer and PVA obtained by saponification thereon. Examples of graftable comonomers include, for example, unsaturated carboxylic acids or their derivatives; unsaturated sulfonic acids or their derivatives; and α-olefins with 2 to 30 carbon atoms. The proportion of structural units derived from the graftable comonomer in PVA(A) is preferably 5 mol% or less relative to all structural units in PVA(A).

[0024] The block character (hereinafter also referred to as "block character") of the vinyl ester unit in PVA(A) can be, for example, 0.3 or more and 0.8 or less, preferably 0.4 or more and 0.6 or less. The lower limit of the block character can be 0.42 or 0.45. The upper limit of the block character can be 0.58, 0.55 or 0.53. When the block character is in the above range, surface activation energy and the like are well exhibited, thereby improving the performance as a dispersant for suspension polymerization. Specifically, for example, it is possible to manufacture polymer particles with better plasticizer absorption. On the other hand, when the block character is in the lower range as described above, there is usually a tendency for the water solubility and solution stability of PVA(A) to decrease. Therefore, when the present invention is applied to PVA(A) having this block character, the improvement of solution stability is of great technical significance.

[0025] The block characterization of PVA refers to a numerical value between 0 and 2, representing the distribution of residual esters (usually alkoxycarbonyl groups) and hydroxyl groups generated through ester saponification. 0 indicates that the residual esters or hydroxyl groups are distributed entirely in block form. As the value increases, the alternation gradually increases, with 1 indicating that the residual esters and hydroxyl groups are completely random, and 2 indicating that the residual esters and hydroxyl groups are completely alternating. The aforementioned residual esters refer to the esters (-OC(=O)-Q (Q represents the hydrocarbon group other than the CH2=CH-OC(=O) portion in the ethylene ester monomer) contained in the ethylene ester unit of the PVA obtained through saponification. In other words, the block characterization is a numerical value representing the distribution of ethylene ester units and ethylene alcohol units. It should be noted that the block characterization can be obtained through... 13 The block characteristics are determined by C-NMR measurements. When the PVA contains repeating units other than ethylene ester units and / or vinyl alcohol units, the block characteristics are calculated using all continuous sites of ethylene ester units and / or vinyl alcohol units in the PVA as the object.

[0026] The aforementioned block characteristics can be adjusted according to the type of ethylene ester monomer, the presence or absence of a chain transfer agent, the catalyst, the solvent, and other saponification conditions. For example, when using an alkaline catalyst for saponification, there is a tendency to obtain PVA with a high block character of 0.6 or less. On the other hand, when using an acid catalyst for saponification, there is a tendency to obtain PVA with a high randomness of block character exceeding 0.6.

[0027] The solution may contain one or more types of PVA (A).

[0028] The lower limit for the PVA(A) content in the solution is sometimes preferably 15% by mass, more preferably 20% by mass, even more preferably 25% by mass, and even more preferably 30% by mass, 35% by mass, or 40% by mass. By setting the PVA(A) content to the above lower limit or above, a high-concentration PVA solution is formed, which allows for effective circulation and storage. Furthermore, by setting the PVA(A) content to the above lower limit or above, the solution tends to have higher stability. The upper limit for the PVA(A) content can be 70% by mass, 60% by mass, 50% by mass, or 40% by mass. By setting the PVA(A) content to below the above upper limit, the solution viscosity can be reduced.

[0029] (Manufacturing method of PVA(A)) PVA(A) can be manufactured, for example, by polymerizing ethylene ester monomers to obtain ethylene ester polymers and by saponifying the resulting ethylene ester polymers.

[0030] Examples of vinyl ester monomers include vinyl formate, vinyl acetate, vinyl propionate, vinyl valerate, vinyl decanoate, vinyl laurate, vinyl stearate, vinyl benzoate, vinyl neopentanoate, and vinyl tert-carbonate. Vinyl acetate is preferred.

[0031] Methods for polymerizing ethylene ester monomers include known methods such as bulk polymerization, solution polymerization, suspension polymerization, and emulsion polymerization. Among these methods, bulk polymerization carried out under solvent-free conditions or solution polymerization using solvents such as alcohols is preferred, and solution polymerization carried out in the presence of lower alcohols is more preferred. As for the lower alcohol, alcohols with 3 or fewer carbon atoms are preferred, and methanol, ethanol, n-propanol, or isopropanol are more preferred, with methanol being even more preferred. When using bulk polymerization or solution polymerization, the reaction can be carried out in either a batch or continuous manner.

[0032] Examples of polymerization initiators used in polymerization reactions include azo initiators such as 2,2'-azobisisobutyronitrile, 2,2'-azobis(2,4-dimethylpentanonitrile), and 2,2'-azobis(4-methoxy-2,4-dimethylpentanonitrile); and known polymerization initiators such as benzoyl peroxide, n-propyl peroxide carbonate, cumyl peroxide neodecanoate, and tert-butyl peroxide neodecanoate. There are no particular limitations on the polymerization temperature, but a range of 5°C to 200°C is preferred.

[0033] When the vinyl ester monomer is polymerized, other copolymerizable monomers can be further copolymerized. Examples of other monomers include those described above that provide other structural units.

[0034] During the polymerization of vinyl ester monomers, specified chain transfer agents can coexist. Examples of chain transfer agents include aldehydes such as acetaldehyde, propionaldehyde, and butyraldehyde; ketones such as acetone and methyl ethyl ketone; thiols such as 2-hydroxyethanethiol and 3-mercaptopropionic acid; thiocarboxylic acids such as thioacetic acid; and halogenated hydrocarbons such as trichloroethylene and perchloroethylene. Chain transfer agents can function as modifiers. Depending on the type of chain transfer agent, specified groups (e.g., carboxyl groups) can be introduced into the ends of PVA(A). When using PVA(A) with carboxyl groups at the ends, there is a tendency for the plasticizer absorption of polymer particles obtained through suspension polymerization to become better. When PVA(A) has carboxyl groups at its ends, these carboxyl groups can exist in the form of salts or anions.

[0035] The saponification of the resulting ethylene ester polymer can be carried out by treating the ethylene ester polymer with an alkaline catalyst or an acid catalyst, for example, in an alcoholic solution. The saponification reaction of the ethylene ester polymer can be performed using existing known alcoholysis or hydrolysis reactions using alkaline catalysts such as sodium hydroxide, potassium hydroxide, or sodium methoxide, or acid catalysts such as p-toluenesulfonic acid. Examples of solvents used in the saponification reaction include alcohols such as methanol and ethanol; esters such as methyl acetate and ethyl acetate; ketones such as acetone and methyl ethyl ketone; and aromatic hydrocarbons such as benzene and toluene. These can be used alone or in combination of two or more. Among these, using methanol or a mixture of methanol and methyl acetate as a solvent, and carrying out the saponification reaction in the presence of sodium hydroxide as an alkaline catalyst, is simple and therefore preferred.

[0036] Saponification can be carried out using belt reactors, kneader reactors, tower reactors, etc. The PVA(A) obtained after saponification can then be cleaned and dried.

[0037] (Compound (B)) Compound (B) is the compound shown in formula (1) below.

[0038] [Chemistry 10] In formula (1), X is an oxygen atom, a group shown in formula (2) below, or a group shown in formula (3) below. Y is a group having 1 to 10 carbon atoms. Z is one selected from carboxyl, sulfonyl, phosphate, their salts, and their anions. R 1 It can be an acyl or hydrocarbon group.

[0039] [Chemistry 11] [Chemistry 12] In equations (2) and (3), R 2 R 3 and R 4 Each is independently a hydrogen atom, an alkyl group with 1 to 3 carbon atoms, or a linker bonded to Y. * indicates a linker bond.

[0040] It can be inferred that the compound (B) achieves the effects of the present invention by having a group containing an electron-withdrawing atom such as an oxygen atom or a nitrogen atom as X, thereby improving the homogeneity of the solution and the separability from PVA (A).

[0041] X is preferably a group shown in formula (2) or formula (3) above, and more preferably a group shown in formula (2) above. When X is a group shown in formula (2) above, R 2 Preferably, it is an alkyl group having 1 to 3 carbon atoms, more preferably a hydrogen atom, methyl or ethyl, further preferably a hydrogen atom or methyl, and even more preferably methyl. When X is a group represented by formula (3) above, R 3 and R 4 Each of the components is preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, more preferably a hydrogen atom, methyl or ethyl, and even more preferably a hydrogen atom or methyl. Additionally, X is preferably a secondary amine, tertiary amine, or quaternary amine, more preferably a secondary or tertiary amine.

[0042] Y is a group having 1 to 10 carbon atoms, preferably a group having 1 to 8 carbon atoms, and more preferably a group having 1 to 5 carbon atoms. Y may contain atoms other than carbon. The atoms in Y other than carbon are preferably selected from at least one of oxygen, nitrogen, and hydrogen, and more preferably hydrogen. Furthermore, Y may bond with X to form a ring structure. In this case, when X is a group as shown in formula (2) above, R... 2 When X is a linking bond to Y and X is a group as shown in formula (3) above, R 3 and R 4At least one of them is a linker bonded to Y. As an embodiment, it is preferable that Y does not bond with X to form a ring structure. As an embodiment, Y can be a hydrocarbon group. Some or all of the hydrogen atoms in this hydrocarbon group may be substituted with other atoms or groups, or may be unsubstituted, preferably unsubstituted or substituted with a carboxyl group, its salt, or its anion. Y is preferably a hydrocarbon group having 1 to 5 carbon atoms, more preferably a straight-chain alkane dimethyl (-(CH2)) having 1 to 5 carbon atoms. n - (n is an integer from 1 to 5), more preferably methylene (-CH2-). Y is also preferably an alkane diester with 1 to 3 carbon atoms. The hydrogen atoms in these alkane diesters may optionally be replaced by carboxyl groups, their salts, or their anions. When Y is a smaller group, the presence of X containing an oxygen or nitrogen atom as an electron-withdrawing atom near Z can further improve the homogeneity of the solution and its separability from PVA (A).

[0043] Z is preferably a salt of a carboxyl group, a salt of a sulfonyl group, or a salt of a phosphate group. Alternatively, as an embodiment, Z is also preferably a carboxyl group, a salt of a carboxyl group, or an anion of a carboxyl group, more preferably a salt of a carboxyl group. Furthermore, when the solution is, for example, an aqueous solution, Z can be an anion of a carboxyl group (-COO). - ), sulfonyl anion (-SO3) - ) or phosphate anion (-HPO4) - or -PO4 2- Additionally, when Z is a sulfonyl group (SO3H-) or a phosphoric acid group (H2PO4-), compound (B) can be a phosphate ester or a sulfonate ester.

[0044] When Z is a salt of a carboxyl group, a sulfonic acid group, or a phosphate group, the type of salt is not particularly limited. Examples of salts include alkali metal salts such as sodium, potassium, and lithium; alkaline earth metal salts such as calcium and magnesium; organic amine salts such as aluminum, zinc, ammonium, monoethanolamine, diethanolamine, triethanolamine, and triisopropanolamine; and basic salts such as arginine and lysine. Among these, alkali metal salts are preferred, and sodium salts are more preferred. The salt form of compound (B) can be obtained, for example, by adding a basic compound or an aqueous solution thereof to compound (B) which is a carboxylic acid, sulfonic acid, or phosphoric acid. For example, to prepare a salt from an N-long-chain acyl amino acid described later, it is sufficient to add a basic compound or an aqueous solution thereof to the N-long-chain acyl amino acid.

[0045] R 1 The number of carbon atoms is, for example, 7 to 24, preferably 8 to 21, more preferably 10 to 14, and even more preferably 11 to 13.

[0046] R 1 Preferably, it is an acyl group. R 1 When it is an acyl group, R 1 Preferably, it is a group represented by the following formula (4).

[0047] [Chemistry 13] In equation (4), R 5 It consists of saturated or unsaturated hydrocarbon groups with 7 to 20 carbon atoms. * indicates a linking bond.

[0048] R 5 The number of carbon atoms is preferably 9 to 13, more preferably 10 to 12. Additionally, R... 5 Preferably, it is a straight-chain saturated or unsaturated hydrocarbon group, more preferably a straight-chain saturated hydrocarbon group. R 5 Saturated hydrocarbon groups are also preferred. As one embodiment, R 5 The best quality is derived from coconut oil.

[0049] R 1 When the hydrocarbon group is a hydrocarbon group, it is preferably a saturated or unsaturated hydrocarbon group with 7 to 21 carbon atoms, more preferably a straight-chain saturated or unsaturated hydrocarbon group with 7 to 21 carbon atoms, and even more preferably a straight-chain saturated hydrocarbon group with 7 to 21 carbon atoms. Regarding R as a hydrocarbon group... 1 Preferably, it is n-octyl, n-decyl, lauryl, or n-tetradecyl.

[0050] In one embodiment, compound (B) preferably has X in formula (1) being a group represented by formula (2) above, and R 1 It is an acyl group. As an embodiment, more preferably: X is a group represented by formula (2) above, Y is a hydrocarbon group with 1 to 5 carbon atoms, Z is a salt of a carboxyl group, and R... 1 R is the group shown in formula (4). 2 It is an alkyl group with 1 to 3 carbon atoms, and R 5 It is a straight-chain saturated hydrocarbon group with 9 to 13 carbon atoms.

[0051] In one embodiment, compound (B) is preferably selected from at least one of phosphate ester salts, acyl amino acid salts, acyl lactates, acyl taurates, alkyl sulfosuccinates, acyl hydrolyzed collagen salts, and acyl hydroxyethanesulfonates, more preferably from at least one of acyl lactates and acyl amino acid salts, and even more preferably from acyl amino acid salts. As an acyl amino acid salt, an N-acyl amino acid salt is more preferably preferred.

[0052] As an N-acyl amino acid salt, it is preferably a salt of an N-acyl amino acid (also called "N-long-chain acyl amino acid") whose amino group is introduced into the amino group of the amino acid by an acyl group derived from a saturated or unsaturated fatty acid with 8 to 21 carbon atoms. The amino acid residue of the N-acyl amino acid salt can be various amino acids such as α-amino acid, β-amino acid, γ-amino acid, or ω-amino acid. The amino group can be an N-methyl or N-ethyl form. In addition, any of the optical isomers, namely the D-form, L-form, or racemic form, is acceptable. Examples of amino acid residues that are N-acyl amino acid salts include glutamic acid, aspartic acid, glycine, sarcosine, alanine, leucine, isoleucine, serine, threonine, cysteine, cystine, methionine, lysine, arginine, phenylalanine, tyrosine, histidine, tryptophan, proline, hydroxyproline, β-aminopropionic acid, γ-aminobutyric acid, anthranilic acid, m-aminobenzoic acid, para-aminobenzoic acid, lanethionine, β-methyllanethionine, cystathionine, and quinoline. The ingredients include caturine, aminomalonic acid, β-hydroxyaspartic acid, α-amino-α-methylsuccinic acid, β-hydroxyglutamic acid, γ-hydroxyglutamic acid, γ-methylglutamic acid, γ-methyleneglutamic acid, γ-methyl-γ-hydroxyglutamic acid, α-aminohexanoic acid, α,α'-diaminohexanoic acid, β,β'-diaminohexanoic acid, α-amino-γ-hydroxyhexanoic acid, α-aminopimelic acid, α-amino-γ-hydroxypimelic acid, β-aminopimelic acid, α-aminooctanoic acid, and α-aminosepiaic acid. Among these, sarcosine is preferred.

[0053] The acyl group in acyl lactates and acyl amino acid salts is preferably derived from a saturated or unsaturated fatty acid with 8 to 21 carbon atoms. This fatty acid can be straight-chain, branched, or cyclic. Examples of fatty acids include, for instance, straight-chain saturated fatty acids such as octanoic acid, nonanoic acid, decanoic acid, undecanoic acid, lauric acid, tridecanoic acid, myristic acid, pentadecanoic acid, palmitic acid, heptadecanoic acid, stearic acid, nonadecanoic acid, and arachidic acid; and 2-butyl-5-methylvaleric acid, 2-isobutyl-5-methylvaleric acid, dimethyloctanoic acid, dimethylnonanoic acid, 2-butyl-5-methylhexanoic acid, methylundecanoic acid, dimethyldecanoic acid, 2-ethyl-3-methylnonanoic acid, 2,2-dimethyl-4-ethyloctanoic acid, methyldocoanoic acid, 2-propyl-3-methylnonanoic acid, methyltridecanoic acid, dimethyldodecanoic acid, 2-butyl-3-methylnonanoic acid, methyltetradecanoic acid, and ethyldecanoic acid. Trialkyl acid, propyl dodecanoic acid, butyl undecanoic acid, pentyl decanoic acid, hexyl nonanoic acid, 2-(3-methylbutyl)-3-methylnonanoic acid, 2-(2-methylbutyl)-3-methylnonanoic acid, butyl ethyl nonanoic acid, methyl pentadecanoic acid, ethyl tetradecanoic acid, propyl tridecanoic acid, butyl dodecanoic acid, pentyl undecanoic acid, hexyl decanoic acid, heptyl nonanoic acid, dimethyl tetradecanoic acid, butyl pentyl heptanoic acid, trimethyl tridecanoic acid, methyl hexadecanoic acid, ethyl pentadecanoic acid, propyl tetradecanoic acid, butyl tridecanoic acid, pentyl dodecanoic acid, hexyl undecanoic acid, heptyl decanoic acid, methyl heptyl nonanoic acid, dipentyl heptanoic acid, methyl heptadecanoic acid, ethyl hexadecanoic acid, propyl Branched-chain saturated fatty acids such as pentadecanoic acid, butyltetradecanoic acid, pentyltridecanoic acid, hexyldodecanoic acid, heptylundecanoic acid, octyldecanoic acid, dimethylhexadecanoic acid, methyloctylnonanoic acid, methyloctadecanoic acid, ethylheptadecanoic acid, dimethylheptadecanoic acid, methyloctyldecanoic acid, methylnonadecanoic acid, methylnonadecanoic acid, dimethyloctadecanoic acid, butylheptadecanoic acid, etc.; octenic acid, nonenoic acid, decenoic acid, undecenoic acid, dodecano-5-enoic acid, decano-4-enoic acid, myrcenoic acid, arbutinic acid, myristic acid, pentadecenoic acid, hexadecenoic acid, palmitoleic acid, heptadecanoic acid, oleic acid, nonadecanoic acid, eicosenoic acid, etc. Straight-chain monoenoic acids such as 11-enoic acid; branched-chain monoenoic acids such as methylheptenic acid, methylnonenoic acid, methylundecenoic acid, dimethyldecenoic acid, methyldodecenoic acid, methyltridecenoic acid, dimethyldodecenoic acid, dimethyltridecenoic acid, methyloctadecenoic acid, dimethylheptadecanenoic acid, and ethyloctadecenoic acid; dienoic or trienoic acids such as linoleic acid, translinoleic acid, tungstenic acid, linolenic acid, translinolenic acid, pseudotungstenic acid, octadecanotic tetraenoic acid, and arachidonic acid; and alkynic acids such as octylalkynic acid, nonylalkynic acid, decylalkynic acid, undecylalkynic acid, dodecylalkynic acid, tridecylalkynic acid, tetradecylalkynic acid, pentadecylalkynic acid, hexadecylalkynic acid, octadecylalkynic acid, nonadecylalkynic acid, and dimethyloctadecylalkynic acid.Cyclic acids such as methylene octadecenoic acid, methylene octadecanoic acid, cyclopentenic acid, cyclopentenylpentanoic acid, cyclopentenylheptanoic acid, cyclopentenylnonanoic acid, cyclopentenylhexanoic acid, cyclopentenyltridecenoic acid, α-cyclopentyl acid, α-cyclohexyl acid, and α-cyclopentylethyl acid. As fatty acids, straight-chain fatty acids are preferred. Furthermore, as fatty acids, saturated fatty acids are preferred, more preferably straight-chain saturated fatty acids, and particularly preferably lauric acid.

[0054] The acyl group in acyl lactates and acyl amino acid salts can be an acyl group derived from fatty acids obtained from natural oils, preferably an acyl group derived from a mixture of fatty acids containing 80% by mass or more of saturated or unsaturated fatty acids with 8 to 21 carbon atoms. Examples of such acyl groups include those derived from coconut oil fatty acids, palm oil fatty acids, linseed oil fatty acids, sunflower oil fatty acids, soybean oil fatty acids, sesame oil fatty acids, castor oil fatty acids, olive oil fatty acids, and camellia oil fatty acids.

[0055] When compound (B) is an acyl amino acid salt, preferred acyl amino acid salts include sodium cocoyl glutamate, TEA cocoyl glutamate, potassium cocoyl glutamate, sodium lauroyl glutamate, TEA lauroyl glutamate, potassium lauroyl glutamate, sodium cocoyl sarcosinate, TEA cocoyl sarcosinate, potassium cocoyl sarcosinate, sodium lauroyl sarcosinate, TEA lauroyl sarcosinate, potassium lauroyl sarcosinate, sodium cocoyl aspartate, TEA cocoyl aspartate, potassium cocoyl aspartate, sodium lauroyl aspartate, TEA lauroyl aspartate, potassium lauroyl aspartate, sodium cocoyl methyl alanine, sodium cocoyl methyl alanine, sodium cocoyl methyl alanine. Examples of suitable salts include: TEA (tetraacetic acid), potassium cocoyl methyl alanine, sodium lauroyl methyl alanine, TEA lauroyl methyl alanine, potassium lauroyl methyl alanine, sodium cocoyl glycinate, TEA cocoyl glycinate, potassium cocoyl glycinate, sodium lauroyl glycinate, TEA lauroyl glycinate, potassium lauroyl glycinate, sodium myristoyl sarcosinate, sodium myristoyl sarcosinate, TEA myristoyl sarcosinate, potassium myristoyl sarcosinate, sodium lauroyl methyl-β-alanine, TEA lauroyl methyl-β-alanine, potassium lauroyl methyl-β-alanine, sodium cocoyl methyl-β-alanine, TEA cocoyl methyl-β-alanine, potassium cocoyl methyl-β-alanine, etc. Among these, lauroyl sarcosinate salts are more preferred, and sodium lauroyl sarcosinate is even more preferred.

[0056] When compound (B) is an acyl lactate, preferred acyl lactates include sodium cocoyl lactate, TEA cocoyl lactate, potassium cocoyl lactate, sodium lauroyl lactate, TEA lauroyl lactate, potassium lauroyl lactate, sodium stearoyl lactate, TEA stearoyl lactate, potassium stearoyl lactate, sodium isostearyl lactate, TEA isostearyl lactate, potassium isostearyl lactate, etc.

[0057] Compound (B) is preferably selected from at least one acid, its salt, and its anion, which have an acid dissociation constant (pKa) of 0 or more and 6.0 or less in water. The lower limit of pKa is more preferably 1.0, and even more preferably 1.5. Furthermore, the upper limit of pKa is more preferably 5.5, and even more preferably 5.0. By making compound (B) an acid or its salt within the above-mentioned pKa range, the solubility of PVA (A) in a solution containing PVA (A) and compound (B) is superior, and the separation of PVA (A) from the solution under weakly acidic conditions (e.g., in a suspension polymerization system) is also superior.

[0058] The solution may contain one or more compounds (B).

[0059] The lower limit for the content of compound (B) in the solution is, for example, 0.1% by mass, preferably 0.5% by mass, more preferably 0.7% by mass, and even more preferably 0.8% by mass or 0.9% by mass. By setting the content of compound (B) to the above lower limit or above, the stability of the solution can be further improved. The upper limit for the content of compound (B) is preferably 10% by mass, more preferably 4% by mass, and even more preferably 2% by mass. By setting the content of compound (B) to the above upper limit or below, the influence of compound (B) during suspension polymerization is further reduced, and the performance of the dispersant for suspension polymerization is further improved.

[0060] (Alcohol (C)) Examples of alcohols (C) include monohydric alcohols such as methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-methyl-1-propanol, 2-butanol, and 2-methyl-2-propanol; and polyhydric alcohols such as ethylene glycol and glycerol. From the viewpoint of the solubility of PVA (A), compatibility with water, and solution viscosity, alcohols with 1 to 4 carbon atoms are preferred as alcohol (C). The number of carbon atoms in alcohol (C) is more preferably 1 to 3, and even more preferably 2. In one embodiment, alcohol (C) is preferably a straight-chain alcohol. Monohydric alcohols are also preferred as alcohol (C), primary alcohols are also preferred, and ethanol is particularly preferred.

[0061] The solution may contain one or more alcohols (C).

[0062] The lower limit for the alcohol (C) content in the solution is, for example, 1% by mass, preferably 3% by mass, more preferably 5% by mass, even more preferably 6% by mass, and even more preferably 7% by mass. By setting the alcohol (C) content to the lower limit or above, the stability of the solution can be further improved. The upper limit for the alcohol (C) content is preferably 80% by mass, more preferably 50% by mass. The alcohol (C) content is sometimes further preferably less than 20% by mass or less than 15% by mass. By setting the alcohol (C) content to the upper limit or below the upper limit, wastewater treatment can be easily carried out, the environmental impact can be reduced, and the treatability is improved.

[0063] More preferably, in this solution, the content of compound (B) is 0.5% by mass or more and 4% by mass or less, and the content of alcohol (C) is 5% by mass or more and 15% by mass or less. In this case, a solution with superior properties as a dispersant in suspension polymerization is formed, and its treatability in wastewater treatment and the like is also excellent.

[0064] (Other ingredients, etc.) The solution may contain water as a component other than PVA (A), compound (B), and alcohol (C). The solution may be an aqueous solution. The lower limit of the water content in the solution may be, for example, 0.1% by mass, 1% by mass, 10% by mass, 20% by mass, 30% by mass, 40% by mass, or 50% by mass. The upper limit of the water content in the solution may be, for example, 90% by mass, 80% by mass, 70% by mass, or 60% by mass.

[0065] The solution may also contain solid components other than PVA (A) and compound (B), and organic solvents other than alcohols, as other components. Examples of solid components other than PVA (A) and compound (B) include resins other than PVA (A), surfactants other than compound (B), plasticizers, and various compounds used in the manufacturing process. The lower limit of the total content of PVA (A), compound (B), alcohol (C), and water in the solution is preferably 90% by mass, more preferably 99% by mass, and even more preferably 99.9% by mass. The upper limit of the total content of PVA (A), compound (B), alcohol (C), and water in the solution can be 100% by mass. Furthermore, the lower limit of the total content of PVA (A) and compound (B) in the solid components of the solution is preferably 90% by mass, more preferably 99% by mass, and even more preferably 99.9% by mass. The upper limit of the total content of PVA (A) and compound (B) in the solid components of the solution can be 100% by mass.

[0066] The upper limit of the viscosity of the solution is preferably 30,000 mPa·s, more preferably 20,000 mPa·s, even more preferably 10,000 mPa·s, even more preferably 5,000 mPa·s, and particularly preferably 3,000 mPa·s. By keeping the viscosity of the solution below the above upper limit, processability and other properties can be improved. The lower limit of the above viscosity can be 1 mPa·s, 10 mPa·s, 100 mPa·s, 500 mPa·s, or 1,000 mPa·s. The viscosity of the solution is set as the value measured using a type B viscometer (measuring shaft: LV-03~LV-04) under the conditions of a rotor speed of 60 rpm and a temperature of 20°C.

[0067] The solution is preferably neutral or alkaline, more preferably neutral or weakly alkaline. In this case, the stability of the solution is further improved. The pH of the solution is preferably 5.0 or higher, more preferably 6.0 or higher. In addition, the pH of the solution is preferably 9.0 or lower, more preferably 8.0 or lower, and can be 7.5 or lower or 7.0 or lower.

[0068] This solution is suitable for use as a dispersant in suspension polymerization. It can also be used for other applications besides being a dispersant in suspension polymerization. This solution can be used as a dispersant in emulsion polymerization, and also for other applications besides being a dispersant. Examples of applications other than being a dispersant include those common to conventional PVA applications.

[0069] <Methods for preparing solutions> As one embodiment of the present invention, the method for manufacturing the solution is not particularly limited, and the solution can be manufactured by, for example, mixing the components. Preferably, the solution is manufactured using the method described below.

[0070] That is, the solution manufacturing method according to one embodiment of the present invention includes a step of adding PVA (A) to a liquid containing compound (B) and alcohol (C) in multiple steps.

[0071] According to this manufacturing method, the solution described in one embodiment of the present invention can be manufactured efficiently. That is, PVA (A), which has low solubility in water or the like, can be effectively dissolved, and a solution with high stability and excellent performance as a dispersant for suspension polymerization can be obtained.

[0072] The number of times PVA (A) is added is not particularly limited as long as it is two or more times; for example, it can be two or more times but less than 20 times, or three or more times but less than 12 times. Furthermore, in this manufacturing method, the liquid containing compound (B) and alcohol (C) may also contain water, etc. The specific and suitable forms of the PVA (A), compound (B), and alcohol (C) used in this manufacturing method are the same as the specific and suitable forms of these components contained in the solution described in one embodiment of the present invention.

[0073] <Dispersant> The dispersant (1) according to one embodiment of the present invention comprises PVA (A) and compound (B). This dispersant (1) is an additive used to improve the dispersibility of monomers and control the plasticizer absorption of the resulting polymer particles during suspension polymerization. The specific and suitable forms of the PVA (A), compound (B), and alcohol (C) (described later as optional components) contained in this dispersant (1) are the same as those of the components contained in the solution described in one embodiment of the present invention.

[0074] The lower limit of the total content of PVA (A) and compound (B) in the non-volatile components of the dispersant (1) is sometimes preferably 30% by mass, more preferably 50% by mass, and even more preferably 70% by mass, 90% by mass, or 99% by mass. The upper limit of the total content of PVA (A) and compound (B) in the non-volatile components of the dispersant (1) can be 100% by mass. Examples of non-volatile components that may be included in the dispersant (1) besides PVA (A) and compound (B) include resins other than PVA (A), surfactants other than compound (B), plasticizers, and various compounds used in the manufacturing process. The upper limit of the content of volatile components in the dispersant (1) is, for example, 80% by mass, but can be 60% by mass or 40% by mass. Examples of volatile components that may be included in the dispersant (1) include alcohols (C) and water.

[0075] The dispersant (1) can be, for example, a solid (powder, etc.) dispersant consisting only of PVA (A) and compound (B). The solid dispersant is well soluble in solvents containing alcohol. The solid dispersant (1) can also be used in alcohol-free solvents (e.g., water). When used as a dispersant in suspension polymerization, the concentration of PVA (A) in the polymerization system is usually not as high as, for example, more than 1% by mass, and therefore it is sufficiently soluble in alcohol-free solvents.

[0076] The dispersant (1) can be in solution form. The dispersant (1) may contain PVA (A) and compound (B), and may also contain alcohol (C), and may contain water. That is, the solution described in one embodiment of the present invention, when used as a dispersant, is one embodiment of the dispersant of the present invention. A dispersant in solution form with a high concentration can also be used after dilution. The dispersant (1) in solution form containing alcohol exhibits high stability.

[0077] The dispersant (1) exhibits excellent performance as a dispersant for suspension polymerization. It is suitable as a dispersant for the suspension polymerization of vinyl compounds, effectively producing polymer particles with a stable average particle size and few coarse particles. Furthermore, the polymer particles obtained through suspension polymerization using this dispersant (1) also exhibit good plasticizer absorption.

[0078] The lower limit of the content of compound (B) in the dispersant (1) relative to 100 parts by mass of PVA (A) is preferably 0.5 parts by mass, more preferably 1 part by mass, and even more preferably 2 parts by mass. By making the content of compound (B) above or above the above-mentioned lower limit, the solubility of PVA (A) can be improved. The upper limit of the content of compound (B) in the dispersant (1) relative to 100 parts by mass of PVA (A) is preferably 20 parts by mass, more preferably 12 parts by mass, and even more preferably 10 parts by mass. By making the content of compound (B) below or below the above-mentioned upper limit, the influence of compound (B) during suspension polymerization is reduced, and the performance of the dispersant is further improved.

[0079] In other embodiments of the present invention, the dispersant (2) is a solution of PVA (A) with a concentration of 15% by mass or more, having a saponification degree of 30 mol% or more and 80 mol% or less, a polymerization degree of 100 or more and 700 or less, and a block characteristic of ethylene ester units of 0.6 or less. This dispersant (2) is an additive used to improve monomer dispersibility during suspension polymerization. This dispersant (2) is suitable for use in the polymerization of vinyl compounds. This dispersant (2) is suitable as a dispersant for suspension polymerization of vinyl compounds, and can effectively obtain polymer particles with a stable average particle size and few coarse particles. Furthermore, the polymer particles obtained by suspension polymerization using this dispersant (2) also exhibit good plasticizer absorption.

[0080] The specific and suitable form of PVA(A) contained in the dispersant (2) is the same as that of PVA(A) contained in the solution described above as an embodiment of the present invention. The lower limit of the concentration of PVA(A) in the dispersant (2) is sometimes preferably 20% by mass, more preferably 25% by mass, further preferably 30% by mass, and even more preferably 35% by mass or 40% by mass. The upper limit of the concentration of PVA(A) can be 70% by mass, or 60% by mass, 50% by mass, or 40% by mass.

[0081] The dispersant (2) preferably comprises at least one (compound (B') selected from acids, their salts, and their anions with an acid dissociation constant (pKa) of 0 or more and 6.0 or less in water. The lower limit of pKa is more preferably 1.0, and even more preferably 1.5. In addition, the upper limit of pKa is more preferably 5.5, and even more preferably 5.0. As such a compound (B'), compounds having a carboxyl group or its salt can be listed. The compound (B') preferably has a hydrocarbon group with 7 to 24 carbon atoms and has a carboxyl group or its salt. The number of carbon atoms of the hydrocarbon group of the compound (B') is preferably 8 to 21, more preferably 10 to 14, and even more preferably 11 to 13. The hydrocarbon group of the compound (B') is preferably an aliphatic hydrocarbon group, and more preferably an alkyl group. As a suitable form of compound (B'), the compound (B) contained in the solution described in one embodiment of the present invention can be listed. In another embodiment of the present invention, the dispersant (2) preferably comprises compound (B).

[0082] The dispersant (2) preferably further comprises an alcohol (C). The specific and suitable forms of the alcohol (C) that may be contained in the dispersant (2) are the same as those of the alcohol (C) contained in the solution described in one embodiment of the present invention and described above. In addition, the specific and suitable forms of the dispersant (2) can be listed as the specific and suitable forms of the solution or dispersant (1) described in one embodiment of the present invention.

[0083] <Methods for manufacturing vinyl compound polymers> A method for manufacturing a vinyl compound polymer according to one embodiment of the present invention includes a step of polymerizing a vinyl compound in the presence of a dispersant according to one embodiment of the present invention. This manufacturing method can be a polymerization method for vinyl compounds. This manufacturing method is the same as conventionally known methods for manufacturing vinyl compound polymers, except that it uses the dispersant according to one embodiment of the present invention as the dispersant.

[0084] In this manufacturing method, the vinyl compound is typically subjected to suspension polymerization in an aqueous medium. As the aqueous medium, in addition to pure water, aqueous solutions containing various additives or aqueous media containing other organic solvents can be used. A dispersant is added to the aqueous medium. A polymerization initiator and the vinyl compound are further added to the aqueous medium, and suspension polymerization is carried out under stirring.

[0085] In one embodiment of the present invention, the amount of dispersant added during suspension polymerization of vinyl compounds is not particularly limited. However, relative to the vinyl compound, it is sometimes preferred to be 1 ppm or more and 50,000 ppm or less in terms of mass based on solid content, more preferably 10 ppm or more and 20,000 ppm or less, and even more preferably 10,000 ppm or less, 5,000 ppm or less, or 1,000 ppm or less.

[0086] The dispersant described in one embodiment of the present invention can be used alone or in combination with other dispersants. Examples of other dispersants include various dispersants commonly used in suspension polymerization of vinyl compounds in an aqueous medium. Specifically, examples include water-soluble cellulose ethers such as methylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, and hydroxypropyl methylcellulose; water-soluble polymers such as PVA (excluding PVA(A)) and gelatin; oil-soluble emulsifiers such as sorbitol monolaurate, sorbitol trioleate, glyceryl tristearate, and ethylene oxide-propylene oxide block copolymers; and water-soluble emulsifiers such as polyoxyethylene sorbitol monolaurate, polyoxyethylene glyceryl oleate, and sodium laurate.

[0087] As the polymerization initiator used in this manufacturing method, substances conventionally used in the polymerization of vinyl compounds can be used; specifically, the same polymerization initiators exemplified in the polymerization of the ethylene ester monomers described above can be used. In one embodiment, the polymerization initiator is preferably an organic peroxide-based initiator. The organic peroxide-based initiator can be a compound having a peroxycarboxylic acid structure (-C(=O)-OO-).

[0088] In this manufacturing method, various other additives can be added to the polymerization system as needed. Examples of additives include polymerization regulators such as aldehydes, halogenated hydrocarbons, and thiols; polymerization inhibitors such as phenolic compounds, sulfur compounds, and N-oxide compounds. Additionally, pH adjusters, antioxidants, and crosslinking agents can also be added. Multiple additives can be used in combination.

[0089] Examples of vinyl compounds capable of suspension polymerization in this manufacturing method include halogenated vinyl groups such as vinyl chloride; vinyl esters such as vinyl acetate and vinyl propionate; acrylic acid, methacrylic acid, their esters and salts; maleic acid, fumaric acid, their esters and anhydrides; styrene; acrylonitrile; vinylidene chloride; and vinyl ethers. Among these vinyl compounds, halogenated vinyl groups are preferred, and vinyl chloride is more preferred. This manufacturing method is particularly suitable as a method for suspension polymerization of vinyl chloride alone, or for suspension polymerization of vinyl chloride together with monomers capable of copolymerizing with vinyl chloride. Examples of monomers capable of copolymerizing with vinyl chloride include vinyl esters such as vinyl acetate and vinyl propionate; (meth)acrylates such as methyl (meth)acrylate and ethyl (meth)acrylate; α-olefins such as ethylene and propylene; unsaturated dicarboxylic acids such as maleic anhydride and itaconic acid; acrylonitrile; styrene; vinylidene chloride; and vinyl ethers. It should be noted that when halogenated vinyl compounds such as halogenated vinylidene chloride and vinylidene chloride are used as vinyl compounds, hydrogen halides are generated as polymerization proceeds, and the polymerization system tends to be weakly acidic. It can be considered that, in the case of a weakly acidic polymerization system, as described above, compound (B) separates from PVA (A), and PVA (A) is not affected by compound (B), thus functioning particularly well as a dispersant for suspension polymerization.

[0090] In this manufacturing method, when the vinyl compound is subjected to suspension polymerization, the feed ratio of each component, polymerization temperature, polymerization time, etc., can be set to the same conditions as those used in conventional suspension polymerization of vinyl compounds. Furthermore, there are no restrictions on the order or ratio of feeding the vinyl compound, polymerization initiator, dispersant, aqueous medium, and other additives.

[0091] According to this manufacturing method, vinyl compound polymer particles with a stable average particle size and few coarse particles can be effectively obtained. Furthermore, the vinyl compound polymer particles obtained by this manufacturing method also exhibit good plasticizer absorption.

[0092] The method for manufacturing a vinyl compound polymer according to other embodiments of the present invention comprises: a preparation step in which a PVA(A) with a saponification degree of 30 mol% or more and 80 mol% or less, a polymerization degree of 100 or more and 700 or less, and a block characteristic of vinyl ester units of 0.6 or less is prepared; and a polymerization step in which a vinyl compound is polymerized in the presence of PVA(A) to obtain vinyl compound polymer particles with an average particle size of 220 μm or less, wherein in the aforementioned preparation step, a solution with a PVA(A) concentration of 15% by mass or more is prepared. The specific form and suitable form of the aforementioned solution prepared by this manufacturing method are the same as the specific form and suitable form of the dispersant (2) of one embodiment of the present invention described above.

[0093] In one embodiment of the present invention, in the method for manufacturing a vinyl compound polymer, a solution of PVA (A) (dispersant (2)) may be introduced into the polymerization reaction system of the vinyl compound during the polymerization step. Alternatively, in this manufacturing method, a solution of PVA (A) (dispersant (2)) may be diluted and introduced into the polymerization reaction system of the vinyl compound during the polymerization step. Example

[0094] The present invention is illustrated by the following embodiments, but the present invention is not limited to these embodiments at all.

[0095] [Manufacturing Example 1] (Manufacturing of PVA-1) 300 parts by mass of vinyl acetate and 1,200 parts by mass of methanol were added to a 3L reaction vessel equipped with a stirrer, reflux condenser, nitrogen inlet, additive inlet, and initiator inlet. After heating to 60°C, the system was purged with nitrogen by bubbling for 30 minutes. 4.8 parts by mass of 2,2'-azobis(4-methoxy-2,4-dimethylpentanonitrile) (AIBN) were added to initiate polymerization. During polymerization, the polymerization temperature was maintained at 60°C, and polymerization was stopped after 4 hours when the polymerization rate reached 50%. Unreacted vinyl acetate was then removed under reduced pressure to obtain a methanol solution of polyvinyl acetate (PVAc). A 10% by mass NaOH methanol solution was added to a PVAc solution adjusted to 40% by mass at an alkali molar ratio (moles of NaOH / moles of vinyl ester units in PVAc) of 0.0025 for saponification. The water content of the saponification solution was adjusted to 1% by mass. Through the above operations, a vinyl alcohol polymer (PVA-1) with a degree of polymerization (viscosity-average degree of polymerization) of 250, a degree of saponification of 43.1 mol%, and a block character of 0.499 was obtained as PVA (A).

[0096] It should be noted that the degree of polymerization of the PVA obtained in each manufacturing example was determined as follows: A methanol solution of PVAc, obtained previously after removing unreacted vinyl acetate and used before the saponification reaction, was added to n-hexane to precipitate the PVAc. After three reprecipitation purifications using acetone, the recovered PVAc was dried under reduced pressure at 60°C to obtain a purified PVAc product. This purified PVAc product was then saponified in a methanol solution at a base molar ratio of 0.2, followed by three days of methanol-based Soxhlet extraction, and then dried to obtain a purified PVA product. The degree of polymerization (viscosity-uniform polymerization degree) of the obtained PVA was determined according to JIS K6726:1994.

[0097] Furthermore, the block characteristics of the ethylene ester units of PVA obtained in each manufacturing example were determined as follows: For samples prepared by dissolving PVA in a mixed solvent of heavy water / deuterated methanol, the tests were conducted at a temperature of 70°C and a cumulative number of tests of 18,000. 13 C-NMR determination was performed by analyzing three peaks in the methylene region related to the binary chain structure (dyad), and the results were obtained from the integral values ​​of these peaks. These three peaks correspond to: the methylene carbon sandwiched between the main chain carbon atom bonded to the residual ester (-OC (=O)-Q (Q has the same meaning as above)) and the main chain carbon atom bonded to the hydroxyl group; the methylene carbon sandwiched between the main chain carbon atom bonded to the residual ester and a nearby carbon atom bonded to the residual ester; and the methylene carbon sandwiched between the main chain carbon atom bonded to the hydroxyl group and a nearby carbon atom bonded to the hydroxyl group. Specific determination and calculation methods are described in POVAL (Polymer Research Council, 1984, pp. 246-249) and Macromolecules, 10, 532 (1977), and were performed according to these descriptions.

[0098] [Manufacturing Examples 2~3] (Manufacturing of PVA-2~3) As shown in Table 1, the molar ratio of sodium hydroxide to vinyl acetate units during saponification (alkali molar ratio) was changed. Otherwise, PVA-2 to PVA-3 were manufactured as PVA (A) by the same method as in Manufacturing Example 1. The physical properties of PVA-2 to PVA-3 are shown in Table 2.

[0099] [Manufacturing Example 4] (Manufacturing of PVA-4) In the saponification process, p-toluenesulfonic acid was used instead of NaOH, and its molar ratio (moles of p-toluenesulfonic acid / moles of vinyl ester units in PVAc) was changed to 0.0210. Otherwise, PVA-4 was manufactured as PVA (A) by the same method as in Manufacturing Example 1. The physical properties of PVA-4 are shown in Table 2.

[0100] [Manufacturing Example 5] (Manufacturing of PVA-5) 1,050 parts by mass of vinyl acetate and 450 parts by mass of methanol were added to a 3L reaction vessel equipped with a stirrer, reflux condenser, nitrogen inlet, additive inlet, and initiator inlet. After heating to 60°C, the system was purged with nitrogen by bubbling for 30 minutes. A 50% by mass solution of 3-mercaptopropionic acid (hereinafter referred to as 3-MPA), acting as a chain transfer agent, was prepared by dissolving it in methanol, and nitrogen purging was performed. The internal temperature of the reaction vessel was adjusted to 60°C. After adding 1.0 part by mass of 3-MPA, 1.2 parts by mass of 2,2'-azobis(4-methoxy-2,4-dimethylpentanonitrile) were added to initiate polymerization. During polymerization, the polymerization temperature was maintained at 60°C, and a 50% by mass methanol solution of 3-MPA was continuously added at a rate of 5 mL / hr, with 3-MPA comprising 11.5 parts by mass in the total system. After 4 hours, when the polymerization rate reached 40%, the polymerization was stopped by cooling. Next, unreacted vinyl acetate was removed under reduced pressure to obtain a methanol solution of modified polyvinyl acetate (modified PVAc). A 10% (w / w) NaOH methanol solution was added to a 40% (w / w) modified PVAc solution at an alkali molar ratio (moles of NaOH / moles of vinyl acetate units in the modified PVAc) of 0.0243, and saponification was performed. The water content of the solution during saponification was adjusted to 1% (w / w). Through the above operations, a vinyl alcohol polymer (PVA-5) with a degree of polymerization of 140, a degree of saponification of 33.0 mol%, a block character of 0.525, and a terminal carboxyl group was obtained as PVA (A).

[0101] It should be noted that the confirmation of whether PVA-5 has a terminal carboxyl salt is performed as follows: The PVA after degree of polymerization was dissolved in heavy water, and nuclear magnetic resonance analysis was performed. The results confirmed the presence of a single terminal carboxyl salt (COONa group) within the molecule.

[0102] [Manufacturing Examples 6~11] (Manufacturing of PVA-6~11) As shown in Table 1, the amounts of vinyl acetate and methanol used in polymerization, the type and amount of chain transfer agent, the amount of AIBN, and the alkali molar ratio during saponification were changed. Otherwise, PVA-6 to 11 were manufactured as PVA (A) using the same method as in Manufacturing Example 5. The physical properties of PVA-6 to 11 are shown in Table 2.

[0103] [Example 1] The solution of Example 1 was obtained by adding 40 parts by mass of PVA-1 to a liquid containing 1 part by mass of sodium lauroyl sarcosinate (Lauroyl sarcosinate Na) as compound (B), 8 parts by mass of ethanol as alcohol (C), and 51 parts by mass of water in 6 separate additions.

[0104] The viscosity of the resulting solution was measured to be 3,110 mPa·s. It should be noted that the viscosity was measured using a Type B viscometer BLII (measuring shaft: LV-04) manufactured by Toki Sangyo Co., Ltd., at a rotor speed of 60 rpm and a temperature of 20°C.

[0105] [Examples 2-30, Comparative Examples 1-5, Reference Example 1] As shown in Table 2, the types and amounts of PVA (A), compound (B), and alcohol (C), as well as the amount of water, were varied. Otherwise, solutions for Examples 2-30, Comparative Examples 1-5, and Reference Example 1 were obtained using the same method as in Example 1. Viscosity measurements were performed on each of the obtained solutions. The results are shown in Table 2.

[0106] [evaluate] (Solution stability) For each solution obtained in Examples 1-30, Comparative Examples 1-5, and Reference Example 1, viscosity was measured using the same method as described above after standing at 40°C for 7 days. The stability of the solution was evaluated based on the viscosity before and after standing, according to the following criteria. In this evaluation, cases A or B were judged to have high stability. The evaluation results are shown in Table 2.

[0107] A: No viscosity change (viscosity increase rate less than 1%).

[0108] B: It has fluidity, but thickens (viscosity increase rate exceeds 1%).

[0109] C: No fluidity, gelation occurs.

[0110] In addition, solutions prepared separately for Examples 1-30, Comparative Examples 3, 5, and Reference Example 1 were used as dispersants, and suspension polymerization of vinyl chloride was carried out using the method described below. It should be noted that the solutions for Comparative Examples 1, 2, and 4 were not used for suspension polymerization due to their low stability. Next, the average particle size, amount of coarse particles, and plasticizer absorption of the resulting vinyl chloride polymer were evaluated according to the following criteria. The evaluation results are shown in Table 2.

[0111] (Suspension polymerization of vinyl chloride) The solid content of each solution from the examples and comparative examples was measured to be 400 ppm relative to vinyl chloride (described later). The measured solutions were diluted with deionized water to obtain a first dispersant aqueous solution. 100 parts by mass of the first dispersant aqueous solution were added to a 5L autoclave. Similarly, the solid content of a PVA aqueous solution containing commercially available PVA (Kuraray POVAL 48-80) was measured to be 800 ppm relative to vinyl chloride. The measured PVA aqueous solution was diluted with deionized water to obtain a second dispersant aqueous solution. 100 parts by mass of the second dispersant aqueous solution were added to the aforementioned autoclave. Next, deionized water was added to the aforementioned autoclave to a total volume of 1300 parts by mass.

[0112] Next, 0.65 parts by mass of a 70% toluene solution of neodecanoate and 1.05 parts by mass of a 70% toluene solution of neodecanoate were added to the autoclave. Degassing was performed until the pressure inside the autoclave reached 0.0067 MPa to remove oxygen. Then, 800 parts by mass of vinyl chloride were added to the autoclave, and the contents were heated to 57°C. Polymerization was initiated with stirring. The initial pressure inside the autoclave was 0.83 MPa. After 3.5 hours, polymerization was stopped when the pressure inside the autoclave reached 0.70 MPa, and unreacted vinyl chloride was removed. The polymer slurry was then removed and dried at 65°C for 17 hours to obtain vinyl chloride polymer particles.

[0113] (1) Average particle size of vinyl chloride polymer particles The particle size distribution of the obtained vinyl chloride polymer particles was determined by dry sieving analysis using a Taylor sieve-based metal mesh. The results were plotted in a Rosin-Rammler distribution, and the average particle size (d) was calculated. p50 (Median particle size). In this evaluation, when the average particle size is below 220 μm, it is judged that the average particle size is not large. Regarding Comparative Examples 3 and 5, the obtained vinyl chloride polymer particles agglomerated, and the average particle size was not determined using the above method, but the average particle size was significantly large.

[0114] (2) The amount of coarse particles in vinyl chloride polymer particles For the obtained vinyl chloride polymer particles, the content of particles that did not pass through a 250 μm sieve (equivalent to 60 mesh in JIS standard sieve conversion) was determined as a percentage by mass. A smaller value indicates fewer coarse particles and better polymerization stability of the dispersant used. In this evaluation, a coarse particle content of less than 10% by mass was considered low. Regarding Comparative Examples 3 and 5, the obtained vinyl chloride polymer particles showed agglomeration. In other words, in Comparative Examples 3 and 5, the particles were essentially all coarse.

[0115] (3) Plasticizer absorption (CPA) of vinyl chloride polymer particles The mass of a 5mL syringe containing 0.02g of absorbent cotton (denoted as X (g)) was measured, and 0.5g of vinyl chloride polymer granules was added to it, with the mass measured (denoted as Y (g)). 1g of dioctyl phthalate (DOP) was added, and the mixture was allowed to stand for 15 minutes. Subsequently, the mixture was centrifuged at 3000 rpm for 40 minutes to remove unabsorbed DOP, and the mass of the residue after removal was measured (denoted as Z (g)). The plasticizer absorption rate (%) of the vinyl chloride polymer granules was then calculated using the following formula. Higher plasticizer absorption rate indicates easier processing, primarily reducing the likelihood of defects such as particulate matter during sheet formation. In this evaluation, a plasticizer absorption rate of 25% or higher was considered good. This evaluation was not performed for Comparative Examples 3 and 5.

[0116] Plasticizer absorption (%) = 100 × [{(ZX) / (YX)} - 1].

[0117] [Table 1] .

[0118] [Table 2] .

[0119] As shown in Table 2, the solutions of Examples 1-30 exhibit high stability. Furthermore, when the solutions of Examples 1-30 are used as dispersants for suspension polymerization, vinyl chloride polymer particles with a stable average particle size, few coarse particles, and good plasticizer absorption are obtained. Therefore, it can be confirmed that the solutions of Examples 1-30 are useful as dispersants for suspension polymerization.

[0120] On the other hand, Comparative Examples 1-5 failed to obtain solutions with high stability containing PVA (A) or the resulting vinyl chloride polymer particles had a large average particle size and many coarse particles.

[0121] It should be noted that when the alcohol (C) content is increased as in Reference Example 1, even solutions without compound (B) exhibit high stability and can be used as dispersants for suspension polymerization. However, as in Comparative Example 4, when the alcohol (C) content is low, solutions without compound (B) exhibit low stability. In contrast, when compound (B) is included as in the solutions of Examples 1-30, solutions with high stability can be obtained regardless of the alcohol (C) content. Furthermore, a comparison between Example 9 and Reference Example 1 confirms that by including compound (B) in the solution, a lower viscosity is achieved.

[0122] Industrial utilization The solution of the present invention can be suitably used as a dispersant for suspension polymerization.

Claims

1. A solution comprising a vinyl alcohol polymer (A), a compound (B), and an alcohol (C), wherein the vinyl alcohol polymer (A) has a saponification degree of 30 mol% or more and 80 mol% or less, and a polymerization degree of 100 or more and 700 or less. Compound (B) is the compound represented by the following formula (1). [Chemistry 1] In formula (1), X is an oxygen atom, a group shown in formula (2) below, or a group shown in formula (3) below; Y is a group with 1 to 10 carbon atoms; Z is selected from carboxyl, sulfonyl, phosphate, their salts, and their anions; R 1 It is an acyl or hydrocarbon group. [Chemistry 2] [Chemistry 3] In equations (2) and (3), R 2 R 3 and R 4 Each is independently a hydrogen atom, an alkyl group with 1 to 3 carbon atoms, or a linking bond bonded to Y; * indicates a linking bond.

2. The solution according to claim 1, wherein, The block character of the vinyl ester unit in the vinyl alcohol polymer (A) is above 0.4 and below 0.

6.

3. The solution according to claim 1, wherein, The content of vinyl alcohol polymer (A) is 15% by mass or more.

4. The solution according to claim 1, wherein, The content of compound (B) is 0.5% by mass or more and 10% by mass or less.

5. The solution according to claim 1, wherein, The content of alcohol (C) is more than 5% by mass and less than 80% by mass.

6. The solution according to claim 1, wherein, The content of alcohol (C) is less than 20% by mass.

7. The solution according to claim 1, wherein, The content of compound (B) is 0.5% by mass or more and 4% by mass or less, and the content of alcohol (C) is 5% by mass or more and 15% by mass or less.

8. A dispersant comprising a vinyl alcohol polymer (A) and a compound (B), wherein the vinyl alcohol polymer (A) has a saponification degree of 30 mol% or more and 80 mol% or less, and a polymerization degree of 100 or more and 700 or less. Compound (B) is the compound represented by the following formula (1). [Chemistry 4] In formula (1), X is an oxygen atom, a group shown in formula (2) below, or a group shown in formula (3) below; Y is a group with 1 to 10 carbon atoms; Z is selected from carboxyl, sulfonyl, phosphate, their salts, and their anions; R 1 It is an acyl or hydrocarbon group. [Chemistry 5] [Chemistry 6] In equations (2) and (3), R 2 R 3 and R 4 Each is independently a hydrogen atom, an alkyl group with 1 to 3 carbon atoms, or a linking bond bonded to Y; * indicates a linking bond.

9. A method for manufacturing a vinyl compound polymer, comprising: a step of polymerizing a vinyl compound in the presence of the dispersant as described in claim 8.

10. A method for manufacturing a solution, comprising: a step of adding a vinyl alcohol polymer (A) to a liquid comprising a compound (B) as shown in formula (1) and an alcohol (C) in multiple separate additions, wherein the vinyl alcohol polymer (A) has a saponification degree of 30 mol% or more and 80 mol% or less, and a polymerization degree of 100 or more and 700 or less. [Chemistry 7] In formula (1), X is an oxygen atom, a group shown in formula (2) below, or a group shown in formula (3) below; Y is a group with 1 to 10 carbon atoms; Z is selected from carboxyl, sulfonyl, phosphate, their salts, and their anions; R 1 It is an acyl or hydrocarbon group. [Chemistry 8] [Chemistry 9] In equations (2) and (3), R 2 R 3 and R 4 Each is independently a hydrogen atom, an alkyl group with 1 to 3 carbon atoms, or a linking bond bonded to Y; * indicates a linking bond.

11. A dispersant, which is a solution of an ethylene alcohol polymer (A) having a saponification degree of 30 mol% or more and 80 mol% or less, a polymerization degree of 100 or more and 700 or less, and a block characteristic of ethylene ester units of 0.6 or less, having a concentration of 15% by mass or more.

12. The dispersant according to claim 11, wherein, The solution contains at least one acid selected from acids, their salts, and their anions that have a dissociation constant (pKa) of 0 or greater and 6.0 or less in water.

13. The dispersant according to claim 11 or 12, used for the polymerization of vinyl compounds.

14. A method for manufacturing vinyl compound polymers, comprising: The preparation process involves preparing a vinyl alcohol polymer (A) with a saponification degree of 30 mol% or more and 80 mol% or less, a polymerization degree of 100 or more and 700 or less, and a block characteristic of ethylene ester units of 0.6 or less; and The polymerization process involves polymerizing vinyl compounds in the presence of a vinyl alcohol-based polymer (A) to obtain vinyl compound polymer particles with an average particle size of less than 220 μm. In the preparation step, a solution of vinyl alcohol polymer (A) with a concentration of 15% by mass or more is prepared.

15. The method for manufacturing the vinyl compound polymer according to claim 14, wherein, The solution in the preparation step contains at least one acid selected from acids, their salts and anions that have a dissociation constant (pKa) of 0 or more and 6.0 or less in water.

16. The method for manufacturing the vinyl compound polymer according to claim 14 or 15, wherein, In the polymerization process, a solution of the vinyl alcohol polymer (A) with a concentration of 15% by mass or more is introduced into the polymerization reaction system of the vinyl compound.

17. The method for manufacturing the vinyl compound polymer according to claim 14 or 15, wherein, In the polymerization process, a solution of the vinyl alcohol polymer (A) with a concentration of 15% by mass or more is diluted and introduced into the polymerization reaction system of the vinyl compound.

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