JP5048969B2 - Method for producing acrylic polymer - Google Patents

Description

  The present invention relates to a method for producing an acrylic polymer by polymerizing a monomer using a polymerization initiator, and more specifically, a method for producing an acrylic polymer in which the kind of polymerization initiator to be used and its addition method are improved, and The present invention relates to a paint, an adhesive and a sealant containing an acrylic polymer obtained by the method for producing the acrylic polymer.

  Conventionally, when a polymer such as an acrylic monomer is polymerized to produce a polymer, a solution polymerization method or a bulk polymerization method has been often employed.

As an example of producing a polymer by a solution polymerization method, the following Patent Document 1 describes a silicon-containing functional group that is composed of a (meth) acrylate monomer unit as a molecular chain and can be crosslinked by forming a siloxane bond. The manufacturing method of the polymer (A) component which has this is disclosed. In patent document 1, the process which superposes | polymerizes a (meth) acrylic acid ester monomer and uses the solvent which does not contain an aromatic solvent as a polymerization solvent is used. As the polymerization solvent, for example, alcohol solvents, carbonyl group-containing solvents, C3-C4 aliphatic alcohols, dialkyl carbonates, and the like can be used.
JP 2003-96106 A

  In Patent Document 1, a polymer (A) component that does not contain an aromatic compound and has a small environmental load can be obtained. However, in Patent Document 1, since a polymer is produced by a solution polymerization method using a solvent, it is necessary to perform an extra step of devolatilizing the solvent after obtaining the polymer. Therefore, the production process is complicated and the polymer cannot be obtained efficiently.

  On the other hand, when a polymer is produced by a bulk polymerization method, there are problems that the viscosity becomes too high during production, a gelled product is formed, and it is difficult to dissipate heat generated by the polymerization reaction. It was. In particular, if the heat generated by the polymerization reaction cannot be sufficiently dissipated, the reaction temperature rises during production, and the reaction temperature may exceed the boiling point of the monomer. Therefore, when bulk polymerization is performed, for example, a high-pressure reaction vessel needs to be used.

  Therefore, after obtaining the polymer, there is no need to perform an extra step of devolatilizing the solvent as in the conventional solution polymerization method, and a special container such as a high-pressure reaction vessel is used as in the conventional bulk polymerization method. Therefore, there has been a strong demand for a method for producing a polymer that can safely polymerize a monomer.

  The object of the present invention is to eliminate the need for an extra step of volatilizing and removing the solvent after obtaining the acrylic polymer, and without using a special vessel such as a high-pressure reaction vessel. An object of the present invention is to provide a method for producing an acrylic polymer capable of safely polymerizing monomers, and a paint, an adhesive and a sealant containing the acrylic polymer obtained by the method for producing the acrylic polymer.

  The present invention is a method for producing an acrylic polymer in which a polymerization initiator is added stepwise to a monomer containing at least an acrylic monomer, and the monomer is polymerized, and the temperature at which the polymerization of the monomer is started as a polymerization initiator is X The polymerization initiator A having a 10-hour half-life temperature in the range of X-5 to X + 5 ° C. is used.

In the production how acrylic polymers according to the present invention, as the polymerization initiator, in addition to the polymerization initiator A, and further using a low polymerization initiator B than ten-hour half-life temperature of polymerization initiator A, the monomer After the polymerization initiator A is added stepwise to polymerize a part of the monomer, the polymerization initiator B is added stepwise to further polymerize the monomer.

  In another specific aspect of the method for producing an acrylic polymer according to the present invention, the monomer contains a polymerization inhibitor, and before the polymerization of the monomer is started, an amount of the polymerization initiator B that consumes the polymerization inhibitor is added. After the polymerization inhibitor is consumed, the monomer is polymerized.

  In still another specific aspect of the method for producing an acrylic polymer according to the present invention, a monomer is polymerized using a normal pressure reaction vessel that performs a reaction at normal pressure under a solvent-free condition.

  In still another specific aspect of the present invention, there is provided a method for producing an acrylic polymer used for a paint, an adhesive or a sealant containing a solvent and / or a plasticizer, wherein after the monomer is polymerized, the paint, the adhesive or A solvent and / or a plasticizer contained in the sealing material is added.

In another specific aspect of the acrylic polymer production method according to the present invention, by using the atmospheric pressure reaction vessel to carry out the reaction at atmospheric pressure, the solvent removal step is unnecessary amounts of removing SOLVENTS after obtaining the acrylic polymer The monomer is polymerized under conditions including a solvent.

In yet another specific aspect of the method of manufacturing the acrylic polymer according to the present invention, by using the atmospheric pressure reaction vessel to carry out the reaction at atmospheric pressure, monomer having no solvent and / or volatilization at temperatures at the time of polymerization of The monomer is polymerized under conditions including a plasticizer.

  In another specific aspect of the present invention, a method for producing an acrylic polymer used in a solvent-containing paint, adhesive or sealing material, wherein the paint, adhesion is produced using an atmospheric pressure reaction vessel that reacts at normal pressure. The monomer is polymerized under the condition including the solvent contained in the agent or the sealing material.

  In the method for producing an acrylic polymer according to the present invention, as a polymerization initiator, when the temperature at the time of initiating the polymerization of the monomer is X, the ten-hour half-life temperature is in the range of X-5 to X + 5 ° C. Since the polymerization initiator is added stepwise to the monomer using the agent A to polymerize the monomer, the polymerization initiator is not rapidly decomposed, and the increase in the reaction temperature during the polymerization of the monomer can be suppressed. it can. Therefore, the monomer can be safely polymerized without using a special vessel such as a high-pressure reaction vessel.

  Furthermore, when the monomer is polymerized, it is not necessary to use a solvent, and even if it is used, it is only necessary to use a small amount of solvent. Therefore, after obtaining the acrylic polymer, it is necessary to perform an extra step of volatilizing and removing the solvent There is no. Therefore, the production efficiency of the acrylic polymer can be increased.

  As a polymerization initiator, in addition to the polymerization initiator A, a polymerization initiator B having a 10-hour half-life temperature lower than that of the polymerization initiator A is further used, and the polymerization initiator A is added stepwise to the monomer. When a part of the polymerization initiator B is polymerized and then the polymerization initiator B is further added stepwise and the monomer is further polymerized, an increase in the reaction temperature during the polymerization of the monomer can be suppressed in the initial stage of the reaction. Furthermore, since the polymerization initiator B that is more easily decomposed than the polymerization initiator A is used, for example, in the latter half of the reaction after polymerizing a part of the monomer, the production efficiency of the acrylic polymer can be further enhanced.

  When the monomer contains a polymerization inhibitor and before the polymerization of the monomer is started, an amount of the polymerization initiator B that consumes the polymerization inhibitor is added, and after the polymerization inhibitor is consumed, the monomer is polymerized, By using the polymerization initiator B that is more easily decomposed than the polymerization initiator A, the polymerization inhibitor can be consumed quickly. Therefore, the polymerization inhibitor can be consumed quickly and the polymerization of the monomer can be started much earlier. Furthermore, when the polymerization initiator A is added for the first time, the polymerization of the monomer can proceed safely and reliably.

  When a monomer is polymerized under a solvent-free condition using a normal pressure reaction vessel that performs a reaction at normal pressure, it is necessary to perform a solvent removal step for removing the solvent after obtaining an acrylic polymer. Absent.

  To provide an acrylic polymer that can be used as a paint, adhesive or sealant when the solvent and / or plasticizer contained in the paint, adhesive or sealant is added after polymerizing the monomer it can.

  When the monomer is polymerized using a normal pressure reaction vessel that carries out the reaction at normal pressure, and the monomer is polymerized under the condition that the solvent removal step of removing the solvent substantially after the acrylic polymer is obtained, Since it is not necessary to perform a solvent removal step for removing the solvent after obtaining the polymer, the acrylic polymer can be produced efficiently.

  When the monomer is polymerized using a normal pressure reaction vessel that carries out the reaction at normal pressure, under conditions including a solvent and / or a plasticizer that is not substantially volatile at the temperature at which the monomer is polymerized, the monomer Thus, the volatilization of the solvent and the plasticizer during the polymerization can be reliably prevented. Therefore, the monomer can be safely polymerized using the atmospheric pressure reaction vessel.

  When a monomer is polymerized under conditions including a solvent contained in a paint, an adhesive or a sealing material using a normal pressure reaction vessel that performs a reaction at normal pressure, the solvent is removed after obtaining an acrylic polymer. An acrylic polymer that can be used as a paint, an adhesive, or a sealant can be provided without performing a solvent removal step.

  The acrylic polymer constructed according to the production method of the present invention can be used as a raw material for paints, adhesives or sealants.

  Details of the present invention will be described below.

  The inventors of the present invention added a polymerization initiator in a stepwise manner to a monomer containing at least an acrylic monomer, and when polymerizing the monomer, when the temperature at the time of initiating polymerization of the monomer is X The present inventors have found that the above-mentioned problems can be achieved by using a polymerization initiator A having a 10-hour half-life temperature in the range of X-5 to X + 5 ° C., and the present invention has been made.

  In the case of solution polymerization of monomers, generally a method of boiling polymerization by heating the solution to the boiling point or a method of constant temperature polymerization at a temperature below the boiling point of the solution while cooling the solution using a temperature controller is performed. Yes. In the conventional solution polymerization method, the temperature of the solution rapidly increases immediately after the polymerization initiator is added to the monomer solution. In the case of the above boiling point polymerization, the solvent cooled in the cooling tube immediately after the addition of the polymerization initiator. There was a problem that the amount of steam increased remarkably. On the other hand, in the case of the above-mentioned constant temperature polymerization, it is necessary to use a cooling device that operates immediately in response to the temperature rise in order to suppress the temperature rise.

  For example, if a polymerization initiator having a relatively low 10-hour half-life temperature is used, the monomer can be polymerized quickly, but the reaction temperature may rise too much and the reaction temperature may exceed the boiling point of the monomer. there were. Therefore, when a polymerization initiator having a relatively low 10-hour half-life temperature is used, it is necessary to use a special container such as a high-pressure reaction container so that safety can be ensured even if the reaction temperature becomes too high. It was.

  Therefore, in the present invention, it is not necessary to use a solvent when polymerizing the monomer, and even if it is used, the monomer is polymerized without using a small amount of solvent and without rapidly increasing the reaction temperature of the monomer or monomer solution. As a polymerization initiator, the polymerization start has a 10-hour half-life temperature in the range of X-5 to X + 5 ° C. so that the monomer can be safely polymerized without using a special vessel such as a high-pressure reaction vessel. Agent A is used.

  In the polymerization of the monomer, by using the polymerization initiator A in the range of X-5 to X + 5 ° C. and adding the polymerization initiator A to the monomer stepwise, the reaction temperature can be increased even in bulk polymerization, for example. The monomer can be polymerized safely without becoming too high.

  If the ten-hour half-life temperature of the polymerization initiator A is less than X-5 ° C, the monomer may react vigorously when the polymerization initiator A is added. When the 10-hour half-life temperature of the polymerization initiator A exceeds X + 5 ° C., the decomposition rate of the polymerization initiator A is too slow, the monomer does not react efficiently, or it is necessary to use a large amount of the polymerization initiator A, A large amount of undecomposed polymerization initiator A may remain in the system.

  The 10-hour half-life temperature of the polymerization initiator is a temperature that requires 10 hours for the polymerization initiator concentration to be halved when the polymerization initiator is held at a certain temperature. The 10-hour half-life temperature of the polymerization initiator can be measured experimentally, for example, by putting the polymerization initiator solution dissolved in an inert solvent into a glass container purged with nitrogen and thermally decomposing it at a constant temperature. Can do.

  The polymerization initiator A is added stepwise to the monomer. The first addition amount of the polymerization initiator A is affected by the molecular weight and reactivity of the monomer, but is within the range of 0.0001 to 0.01 parts by weight with respect to 100 parts by weight of the total amount of monomers. Is preferred. When the first addition amount of the polymerization initiator A is within this range, the polymerization of the monomer can be started thermally and stably.

  The polymerization initiator A is added stepwise to the monomer, but is preferably added in two to five times. The addition amount of the polymerization initiator A after the second time is affected by the molecular weight and reactivity of the monomer, but in the range of 0.0001 to 0.1 parts by weight with respect to 100 parts by weight of the total amount of monomers. Preferably there is.

  In the present invention, in addition to the polymerization initiator A, it is preferable to further use a polymerization initiator B having a 10-hour half-life temperature lower than that of the polymerization initiator A as the polymerization initiator. And after adding the polymerization initiator A to a monomer in steps and superposing | polymerizing a part of monomer, it is preferable to further add the polymerization initiator B in steps and to superpose | polymerize a monomer further.

  In this case, since the polymerization initiator A is used at the initial stage of the reaction, the monomer can be polymerized under relatively mild conditions. Therefore, the monomer reaction temperature does not increase excessively, and the monomer can be polymerized thermally and stably without using a special vessel such as a high-pressure reaction vessel.

  Furthermore, since the polymerization initiator B that is more easily decomposed than the polymerization initiator A is used, for example, in the latter half of the reaction when the monomer is reduced, the monomer can be polymerized more efficiently than when only the polymerization initiator A is used. That is, when the polymerization initiator B is added, a part thereof is polymerized to reduce the amount of monomers, and the polymerized acrylic polymer acts to reduce the reaction rate between the monomers. Therefore, even when the polymerization initiator B that is more easily decomposed than the polymerization initiator A is used, the reaction of the monomer does not proceed rapidly, and the monomer can be polymerized thermally and stably.

  The 10-hour half-life temperature of the polymerization initiator B has a 10-hour half-life temperature lower than that of the polymerization initiator A. When X is the temperature at which the polymerization of the monomer is initiated, X-50 to X A range of −20 ° C. is more preferable. When the 10-hour half-life temperature of the polymerization initiator B is less than X-50 ° C, the reaction temperature may increase excessively when the polymerization initiator B is added. When the 10-hour half-life temperature of the polymerization initiator B exceeds X-20 ° C., the decomposition rate of the polymerization initiator B is too slow and the monomer does not react efficiently, or it is necessary to use a large amount of the polymerization initiator B. In some cases, a large amount of undecomposed polymerization initiator B may remain in the system.

  The polymerization initiator B is added stepwise to the monomer. The first addition amount of the polymerization initiator B is affected by the molecular weight and reactivity of the monomer, but is within the range of 0.0001 to 0.01 parts by weight with respect to 100 parts by weight of the total amount of monomers. Is preferred. When the first addition amount of the polymerization initiator B is within this range, the monomer can be polymerized thermally and stably.

  The polymerization initiator B is added stepwise to the monomer, but is preferably added in 2 to 10 times. The addition amount of the polymerization initiator B after the second time is influenced by the molecular weight and reactivity of the monomer, the target reaction rate, etc., but is 0.0001 to 2 wt. The range of parts is preferred.

  When the polymerization initiator A and the polymerization initiator B are used in combination, the monomer can be polymerized safely and efficiently. Therefore, the use ratio of the polymerization initiator A and the polymerization initiator B is 1/1000: 1 by weight. It is preferable to be in the range of ˜1 / 100: 1.

  The polymerization initiator A and the polymerization initiator B are not particularly limited. For example, a peroxide-based or azo-based polymerization initiator having a suitable ten-hour half-life temperature may be selected and used. it can.

  Specific examples of the polymerization initiator include organic peroxide polymerization initiators such as benzoyl peroxide, di-t-butyl peroxide, cumene hydroperoxide, and t-butyl peroxybenzoate; Although radical polymerization initiators, such as azo polymerization initiators, such as' -azobis (2-methylbutyronitrile) and 2,2'-azobiscyclohexanecarbonitrile, are mentioned, it is not specifically limited.

  If the monomer contains a polymerization inhibitor, add the polymerization initiator B in an amount that consumes the polymerization inhibitor before starting the polymerization of the monomer, and after the polymerization inhibitor is consumed, polymerize the monomer. Is preferred. When the polymerization inhibitor is consumed using the polymerization initiator A, it is necessary to use a large amount of the polymerization initiator A to consume the polymerization inhibitor, or it takes a long time to consume the polymerization inhibitor. There is. On the other hand, when the polymerization initiator B, which is easier to decompose than the polymerization initiator A, is used, the polymerization inhibitor can be consumed quickly. Therefore, the monomer polymerization can be started more quickly after the polymerization inhibitor is consumed quickly.

  The content of the polymerization inhibitor varies depending on the monomer, and the addition amount of the polymerization initiator B for consuming the polymerization inhibitor is determined from the monomer used. The addition amount of the polymerization initiator B that consumes the polymerization inhibitor is not particularly limited because it is influenced by the purity and reactivity of the polymerization initiator B, and specifically, it is 1/3 to 2/2 of the polymerization inhibitor. A range of 3 equivalents is preferred.

  The amount that consumes the polymerization inhibitor is an amount that allows the polymerization of the monomer to be started without being inhibited by the polymerization inhibitor when the first polymerization initiator A is added later. It means that. As to whether or not the polymerization inhibitor is consumed, for example, while adding the polymerization initiator B to the monomer little by little, the decrease amount of the polymerization inhibitor is measured using gas chromatography or liquid chromatography, This can be confirmed by measuring the reaction temperature.

  The monomer used in the present invention is not particularly limited as long as it is a monomer containing at least an acrylic monomer.

  Although it does not specifically limit as said acrylic monomer, Acrylic acid ester or methacrylic acid ester etc. are mentioned. The acrylic ester or methacrylic ester is not particularly limited. (Meth) acrylic acid, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate , N-butyl (meth) acrylate, isobutyl (meth) acrylate, sec-butyl (meth) acrylate, tert-butyl (meth) acrylate, n-hexyl (meth) acrylate, cyclohexyl (meth) acrylate , N-octyl (meth) acrylate, isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, decyl (meth) acrylate, lauryl (meth) acrylate, isobornyl (meth) acrylate, (meth) Benzyl acrylate, phenyl (meth) acrylate, (meth) acrylic acid Teariru include dimethylaminoethyl (meth) acrylic acid.

  The monomer other than the acrylic monomer is not particularly limited as long as it is a monomer copolymerizable with the acrylic monomer. The monomer other than the acrylic monomer is not particularly limited, and examples thereof include vinyl ester monomers and styrene monomers.

  The vinyl ester monomer is not particularly limited, and vinyl acetate, vinyl formate, vinyl propionate, vinyl butyrate, vinyl n-caproate, vinyl isocaproate, vinyl octoate, vinyl laurate, vinyl palmitate, vinyl stearate. , Vinyl trimethyl acetate, vinyl pivalate, vinyl chloroacetate, vinyl trichloroacetate, vinyl trifluoroacetate, vinyl benzoate and the like.

  The styrene monomer is not particularly limited, and is styrene, α-methylstyrene, p-methylstyrene, m-methylstyrene, o-methylstyrene, 2,4-dimethylstyrene, 2,5-dimethylstyrene, p- Examples include ethyl styrene, p-isopropyl styrene, p-chloromethyl styrene, p- (2-chloroethyl) styrene.

  Since it is not necessary to perform a solvent removal step to remove the solvent after obtaining the acrylic polymer, the monomer is polymerized under solvent-free conditions using a normal pressure reaction vessel that performs the reaction at normal pressure. Is preferred.

  It is preferable to add a solvent and / or a plasticizer contained in the paint, adhesive or sealant after polymerizing the monomer. In this case, an acrylic polymer that can be used as a paint, an adhesive, or a sealant can be provided.

  Although it does not specifically limit as a solvent contained in a coating material, an adhesive agent, or a sealing material, Alcohol, ester, etc. can be mentioned.

  Although it does not specifically limit as a plasticizer contained in a coating material, an adhesive agent, or a sealing material, Polyacrylic acid ester with a molecular weight of several hundred to several thousand, polyester, etc. can be mentioned.

  It is preferable to polymerize the monomer using a normal pressure reaction vessel that performs the reaction at normal pressure, under conditions that include an amount of solvent that does not require a solvent removal step of substantially removing the solvent after obtaining the acrylic polymer. In this case, after the acrylic polymer is obtained, it is not necessary to perform a solvent removal step for removing the solvent, so that the acrylic polymer can be produced efficiently.

  The amount that does not require a solvent removal step that substantially removes the solvent means that the amount of the solvent is a slight amount that does not cause a problem in practical use of the acrylic polymer even if the obtained acrylic polymer contains the solvent. Means. Specifically, the amount of solvent that does not require a solvent removal step for substantially removing the solvent is preferably in the range of 1 to 25 parts by weight with respect to 100 parts by weight of the total amount of monomers.

  When the monomer is polymerized using a normal pressure reaction vessel that carries out the reaction at normal pressure, under conditions including a solvent and / or a plasticizer that is not substantially volatile at the temperature at which the monomer is polymerized, the monomer Thus, volatilization of the solvent and plasticizer during the polymerization can be reliably prevented, and the monomer can be polymerized safely.

  The solvent having no volatility is affected by the temperature at which the monomer is polymerized and is not particularly limited, but examples thereof include fatty acid esters and higher alcohols, and are preferably used.

  The volatile plasticizer is influenced by the temperature at which the monomer is polymerized and is not particularly limited, and examples thereof include polyacrylic acid esters and polyesters having a molecular weight of several hundred to several thousand, and are preferably used. .

  When a monomer is polymerized under conditions including a solvent contained in a paint, an adhesive or a sealing material using a normal pressure reaction vessel that performs a reaction at normal pressure, the solvent is removed after obtaining an acrylic polymer. An acrylic polymer that can be used as a paint, an adhesive, or a sealant can be provided without performing a solvent removal step.

  As the solvent contained in the paint, adhesive or sealant, the above-mentioned solvents generally contained in the paint, adhesive or sealant are appropriately used. The solvent content when the monomer is polymerized under the conditions including the solvent contained in the paint, adhesive or sealant is the amount of solvent generally contained in the paint, adhesive or sealant, that is, the total amount of monomer. It is preferable that it is the range of 1-25 weight part with respect to 100 weight part.

  The acrylic polymer constituted according to the production method of the present invention can be suitably used as a raw material for paints, adhesives or sealants. Paints, adhesives and sealants containing acrylic polymers constructed according to the production method of the present invention are also one aspect of the present invention.

  Hereinafter, the effects of the present invention will be clarified by giving examples and comparative examples of the present invention. In addition, this invention is not limited to a following example.

(Materials used)
Butyl acrylate (acrylic monomer, Nippon Shokubai Co., Ltd., 15ppm polymerization inhibitor included)
DMAEA (acrylic monomer, N, N-dimethylaminoethyl acrylate, manufactured by Kojin Co., Ltd., containing 2000 ppm polymerization inhibitor)
n-DDM (chain transfer agent, n-dodecyl mercaptan, manufactured by Wako Pure Chemical Industries, Ltd.)
Solmic AP-7 (solvent, industrial alcohol, Nippon Alcohol, boiling point of about 80 ° C)
Rick Sizer C-401 (solvent, fatty acid ester, manufactured by Ito Oil Co., Ltd.)
Perhexa TMH (polymerization initiator A, manufactured by NOF Corporation, 10-hour half-life temperature 86.7 ° C)
Perhexyl PV (polymerization initiator B, manufactured by NOF Corporation, 10-hour half-life temperature 53.2 ° C.)
Perhexyl Z (polymerization initiator A, manufactured by NOF Corporation, 10-hour half-life temperature 99.4 ° C.)
Perhexyl O (polymerization initiator A, manufactured by NOF Corporation, 10-hour half-life temperature 69.9 ° C)

Example 1
After placing 100 parts by weight of butyl acrylate and 5 parts by weight of n-DDM in a flask as a normal pressure reaction vessel for performing reaction at normal pressure, the inside of the flask was purged with nitrogen. Thereafter, the flask was placed in a 90 ° C. water bath, and the inside of the flask was heated to 90 ° C.

  Next, after the time shown in the following Table 1 has elapsed since the start of the polymerization reaction and after the start of the reaction, perhexa TMH as the polymerization initiator A in the amount shown in the following Table 1 was added to polymerize a part of the acrylic monomer. did. After addition of the polymerization initiator A, after the time shown in the following Table 1 had elapsed from the start of the reaction, perhexyl PV as an amount of the polymerization initiator B shown in the following Table 1 was added, and an acrylic monomer was further polymerized.

  After 7 hours from the start of the reaction, the flask was cooled to complete the polymerization reaction.

(Examples 2 to 4 and Comparative Examples 1 and 2)
Except for changing the types and blending amounts of the materials used, the addition temperature, addition timing and addition amount of the polymerization initiators A and B, the flask cooling time and the reaction end time as shown in Tables 1 to 3 below. The acrylic monomer was polymerized in the same manner as in Example 1.

(Evaluation of Examples and Comparative Examples)
[Acrylic monomer polymerization rate]
Acrylic monomer polymerization rate was measured using n-heptane as an internal standard using gas chromatography (manufactured by Shimadzu Corporation, column: PEG 1500).

  After all of the polymerization initiator A was added, the polymerization rate of the acrylic monomer in the flask immediately before adding the first polymerization initiator B was determined. Furthermore, all the polymerization initiators B were added, and the polymerization rate of the acrylic monomer after completing the polymerization reaction was determined.

[Molecular weight of acrylic polymer]
After all of the polymerization initiator B was added and the polymerization reaction was completed, the number average molecular weight (Mn) and the weight average molecular weight (Mw) of the obtained acrylic polymer were determined by gel permeation chromatography (GPC, manufactured by Waters, column). : Showa Denko Co., Ltd., polystyrene gel LF-804, solvent: THF, flow rate: 1 mL / min), and measured in terms of polystyrene.

  Furthermore, the molecular weight distribution (Mw / Mn), which is the ratio of the measured weight average molecular weight (Mw) to the number average molecular weight (Mn), was determined.

  The results are shown in Table 1 below.

  In the production method of Comparative Example 1, since the ten-hour half-life temperature of perhexyl Z was high, it was necessary to use a large amount of a polymerization initiator. Further, in the production method of Comparative Example 2, since the ten-hour half-life temperature of perhexyl O was low, it was necessary to add a polymerization initiator little by little in order to prevent the monomer from reacting violently.

Claims (8)

A method for producing an acrylic polymer, wherein a polymerization initiator is added stepwise to a monomer containing at least an acrylic monomer, and the monomer is polymerized,
As the polymerization initiator, a polymerization initiator A having a 10-hour half-life temperature in the range of X-5 to X + 5 ° C. when the temperature when starting the polymerization of the monomer is X ,
As the polymerization initiator, in addition to the polymerization initiator A, a polymerization initiator B having a 10-hour half-life temperature lower than that of the polymerization initiator A is further used.
The polymerization initiator A stepwise added to the monomer after polymerization of a portion of the monomer, adding the polymerization initiator B stepwise, characterized that you further polymerizing said monomer, A method for producing an acrylic polymer. The method for producing an acrylic polymer according to claim 1, wherein the acrylic monomer is an acrylic ester or a methacrylic ester. The monomer contains a polymerization inhibitor;
The polymerization initiator B is added in an amount that consumes the polymerization inhibitor before the polymerization of the monomer is started, and after the polymerization inhibitor is consumed, the monomer is polymerized. 3. A method for producing an acrylic polymer according to 1 or 2.   The method for producing an acrylic polymer according to any one of claims 1 to 3, wherein the monomer is polymerized under a solvent-free condition containing no solvent using a normal pressure reaction vessel that performs the reaction at normal pressure. A method for producing an acrylic polymer used in a paint, adhesive or sealant containing a solvent and / or a plasticizer,
5. The acrylic polymer according to claim 1, wherein after the monomer is polymerized, a solvent and / or a plasticizer contained in the paint, adhesive, or sealant is added. Production method. Using atmospheric pressure reaction vessel to carry out the reaction at atmospheric pressure, at conditions including a solvent removal step is unnecessary amount of solvent to remove the Solvent after obtaining the acrylic polymer, polymerizing the monomer, claim 1 4. The method for producing an acrylic polymer according to any one of 3 above. Using atmospheric pressure reaction vessel to carry out the reaction at atmospheric pressure, in conditions including without solvent and / or plasticizer volatilization at temperatures at the time of polymerizing the monomer, polymerizing the monomer, claims 1 to 3 The manufacturing method of the acrylic polymer of any one of these. A method for producing an acrylic polymer used in a solvent-containing paint, adhesive or sealant,
The said monomer is polymerized on the conditions containing the solvent contained in the said coating material, an adhesive agent, or a sealing material using the normal pressure reaction container which reacts by a normal pressure, The 1-3 characterized by the above-mentioned. The method for producing an acrylic polymer according to any one of 7 and 7.