JP3489893B2 - Polymethacrylate having a functional group at one end and method for producing the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polymethacrylate having a functional group at one end and a method for producing the same. The polymethacrylate having a functional group at one end of the present invention utilizes the reactivity of the functional group to utilize a resin modifier or a compatibilizer used in polymer blend alloy or reactive processing, or a raw material thereof. Is useful as

[0002]

2. Description of the Related Art In order to satisfy the requirements for high performance and high functionality for polymer materials, a polymer blend alloy combining two or more kinds of polymers has been actively used. When different kinds of polymers are mixed, in many cases, the respective polymers are incompatible with each other and thus macroscopically phase-separate, and the physical properties of the obtained products are extremely deteriorated as compared with the physical properties of the respective polymers before mixing. Therefore, in order to bring out the advantages of each polymer by mixing different kinds of polymers, a method of controlling the morphology by using a compatibilizer together is widely used. As the compatibilizer, various random,
Block or graft copolymers have been used.

As a method for synthesizing a block or graft copolymer, a method using a reactive polymer having a functional group is known. Particularly, a polymer having a polymerizable functional group such as a carboxyl group, an amino group, a hydroxyl group, and a carbon-carbon double bond-containing group at the terminal of the main chain of the molecule is called a macromonomer, and a copolymer having a controlled structure is comparatively used. It has the feature that it can be easily synthesized, and that it is possible to synthesize a copolymer that is difficult to synthesize by other methods.

As a typical example of a method for synthesizing a polymethacrylate macromonomer, a molecular main chain fragment comprising a radical polymerization of a methacrylate such as methyl methacrylate using a carboxyl group-containing mercaptan compound such as mercaptoacetic acid as a chain transfer agent. A method for synthesizing polymethacrylate having a carboxyl group at the terminal is known. In the above synthetic method, as the mercaptan compound-based chain transfer agent, by using those containing a functional group other than the carboxyl group, the functional group located at one end of the main chain of the resulting polymethacrylate is a functional group other than the carboxyl group. It can be changed to a base. For example, if 2-mercaptoethanol is used as a functional group-containing mercaptan compound-based chain transfer agent, polymethacrylate having a hydroxyl group at one end can be synthesized, and if 2-aminoethanethiol hydrochloride is used, at one end. A polymethacrylate having an amino group can be synthesized (Japanese Patent Laid-Open No. Sho 5)
8-59202, JP-A-62-250012, Journal of Polymer Science: Part A: Polymer Chemistry
nce: Part A: Polymer Chemistry), Volume 27, Volume 20
07-2014 (1989) etc.). In addition, in JP-A-62-250012, as a polymerization initiator,
It is described that an azo compound is preferable because it can avoid a reaction with a mercaptan compound-based chain transfer agent.
Further, in the same publication, when the number average molecular weight of polymethacrylate having a functional group at one end is less than 1000, the residual amount of the mercaptan compound which is a chain transfer agent increases,
This causes side reactions when using polymethacrylate as macromonomer, and
It is described that the ratio of the polymethacrylate having a functional group at one end in the produced polymethacrylate decreases when the ratio exceeds the range.

[0005]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
As is clear from the description of JP-A No. 0012, in a method for producing a polymethacrylate having a functional group at one terminal, which comprises radical polymerization of methacrylate in the presence of a functional group-containing mercaptan compound chain transfer agent, a chain transfer agent is used. From the viewpoint of reducing the remaining amount of unreacted substances such as, it is more advantageous when the number average molecular weight of the obtained polymethacrylate is higher, but in that case, conversely, the total number of moles of the generated polymethacrylate is On the other hand, there is an unfavorable tendency that the ratio of the number of moles of the target polymethacrylate having a functional group at one end (hereinafter, referred to as a functional group introduction rate) becomes small. As a result of the inventors' study on the synthesis of a polymethacrylate having a functional group at one end, (1) the polymethacrylate having a number average molecular weight of less than about 20,000 has a solubility with an unreacted monomer or a chain transfer agent. Since they are similar, it is difficult to separate and purify them by a simple method such as reprecipitation after polymerization.Because of their low melt viscosity, they are used as a macromonomer. Polymer blend alloy, reactive processing When melt-kneading with other polymer for the purpose of, for example, the difference in melt viscosity between the two becomes large and it becomes difficult to sufficiently knead, and (2) separation / purification after polymerization and the mixing with other polymer From the viewpoint of melt-kneading, it is particularly advantageous that the number average molecular weight of the polymethacrylate having a functional group at one end is 30,000 or more. It has been found.

Based on the data described in the above-mentioned Journal of Polymer Science, the functional group introduction rate was 7
It is estimated that polymethacrylate having a high value of 0% or more was obtained, but its number average molecular weight is 100.
It is limited to relatively low ones of 00 or less. The production method described in JP-A-58-59202 is for obtaining a polymethacrylate having a terminal functional group and having a number average molecular weight of about 300 to 9000, and the only specific production example thereof, 2-mercaptoethanol chain. Even in the polymerization reaction of a monomer containing methyl methacrylate as a main component and 2-hydroxyethyl acrylate as a copolymerization component in the presence of a transfer agent and a benzoyl peroxide polymerization initiator, the number average molecular weight of the obtained polymethacrylate was about 4000. Not too much. Also in the production example of the polymethacrylate having a functional group at the terminal specifically described in JP-B-43-11224, the number average molecular weight of the obtained polymethacrylate is limited to a relatively low number average molecular weight of 5000 or less. ing. In the method adopted in this production example, since a compound having a functional group is used not only as a chain transfer agent but also as a polymerization initiator, it is difficult to avoid by-product of polymethacrylate having functional groups at both ends of the main chain of the molecule. However, when it is used as a macromonomer, it has a drawback that it easily causes a gelation phenomenon due to the formation of crosslinks.
Also, in the production example of the polymethacrylate having a functional group at the terminal specifically described in JP-B-62-250012, the number average molecular weight of the obtained polymethacrylate is no more than 10200.

The present inventors have tried to improve the molecular weight of the polymethacrylate obtained by lowering the ratio of the chain transfer agent to the monomer in the above-mentioned various known methods. When the average molecular weight is 20,000 or more, the functional group introduction ratio is 70.
Only low numbers, less than%, were achieved.

An object of the present invention is that a high number average molecular weight facilitates separation and purification, is suitable for melt-kneading with other polymers, and has a high functional group introduction rate. An object of the present invention is to provide a polymethacrylate having and a production method suitable for producing the polymethacrylate.

[0009]

According to the present invention, firstly, a main chain is composed of a substantially linear polymethacrylate chain, and one end of the main chain has a general formula.

[0010]

Embedded image —S—R ¹ (−Z ¹ ) (− Z ² ) (I)

(In the formula, R ¹ represents a trivalent hydrocarbon group,
Z ¹ represents an amino group, a carboxyl group or a hydroxyl group,
Z ² represents a hydrogen atom, an amino group, a carboxyl group or a hydroxyl group)

A polymethacrylate having a number average molecular weight of 20,000 or more containing 0.7 to 1 group represented by the average value per molecule.

Secondly, according to the present invention, when the methacrylate is radical-polymerized in the presence of a functional group-containing mercaptan compound chain transfer agent and an azo compound polymerization initiator, the concentration C of the azo compound polymerization initiator is Formula

[0014]

[Equation 2] C · kd ≦ 5 × 10 ⁻⁸ (A)

(In the formula, C represents the concentration (mol / liter) of the azo compound-based polymerization initiator, and kd represents the initiation reaction rate constant of the azo compound-based polymerization initiator under the same temperature conditions as the above radical polymerization. 1 / sec)

A method for producing a polymethacrylate having a functional group at one end, which comprises performing radical polymerization under conditions satisfying

The polymethacrylate chain constituting the molecular main chain of the polymethacrylate of the present invention is a substantially linear polymer chain having a methacrylate component as a main repeating unit. Here, as the methacrylate component, a general formula

[0018]

Embedded image —CH ₂ —C (CH ₃ ) (COOR ² ) — (II)

(In the formula, R ² represents a monovalent hydrocarbon group)

The unit represented by is preferred. Examples of the monovalent hydrocarbon group represented by R ² include methyl, ethyl and n-
An alkyl group having 1 to 8 carbon atoms such as butyl and t-butyl;
Preferred is a cycloalkyl group having 6 to 12 carbon atoms such as cyclohexyl; and a monovalent hydrocarbon group having 1 to 12 carbon atoms such as aralkyl group having 7 to 9 carbon atoms such as benzyl. The methacrylate component constituting the polymethacrylate chain may be one type or two or more types.

Examples of the trivalent hydrocarbon group represented by R ¹ in the general formula (I) include methine, ethylidyne, 1,
1,2-ethanetriyl, propyridine, 1,2,3-
Propanetriyl, 1,1,2-propanetriyl,
Examples thereof include trivalent saturated aliphatic hydrocarbon groups having 1 to 3 carbon atoms such as 1,1,3-propanetriyl and 1,2,2-propanetriyl.

The number of functional groups represented by the formula --SR ¹ (--Z ¹ ) (-Z ² ), which the polymethacrylate of the present invention has at one end of the main chain of the molecule, is the average per molecule. The value is within the range of 0.7 to 1. The average value of the number is 0.7
If it is less than the number of polymethacrylate molecules, the proportion of polymethacrylate molecules having no functional group at the end is large, so when used as a macromonomer, the resulting copolymer does not contain polymethacrylate having no functional group at the end. A large amount of the reaction mixture is mixed in, and the original performance of the resulting copolymer is lost or diluted. On the other hand, if the average value of the number is larger than 1, the proportion of polymethacrylate molecules containing functional groups at both ends of the main chain is large, and when used as a macromonomer, gelation occurs due to the formation of a crosslinked structure. It is easy to occur. The presence ratio of polymethacrylate molecules having a functional group only on one side of the terminal of the main chain of the molecule is particularly high, and the change in performance and gelation as described above when used as a macromonomer is particularly effectively suppressed. The average value of the numbers is preferably within the range of 0.8 to 1. The average value of the number of the functional groups contained in the polymethacrylate is the number average molecular weight in terms of standard polystyrene measured by gel permeation chromatography (hereinafter abbreviated as GPC), and the functional group content per unit weight of the polymethacrylate. It can be calculated from the quantity. The functional group content per unit weight is, for example, when the functional group is an amino group, by neutralization titration with an acid such as perchloric acid, and when the functional group is a carboxyl group, an alkali metal hydroxide or alkoxide. It can be appropriately determined by neutralization titration using a base such as. Further, in ¹ H-NMR measurement, the peak between the proton in the functional group represented by the formula —S—R ² (—Z ¹ ) (— Z ² ) and the proton of the α-methyl group in the methacrylate component in the polymethacrylate chain It can also be obtained from the area ratio. The average value (number / molecule) per molecule of the number of functional groups contained in polymethacrylate is converted into a percentage display, which corresponds to the above-mentioned functional group introduction rate.

The number average molecular weight of the polymethacrylate of the present invention is 20,000 or more. Number average molecular weight is 20,000
If it is less than 1, the melt viscosity becomes low, and other one or two kinds are used for the purpose of polymer blend alloy, reactive processing, etc., which is one usage form as a macromonomer.
When melt kneading with at least one polymer, the difference in melt viscosity is large, and it becomes difficult to sufficiently knead. In this respect, the number average molecular weight is preferably 25,000 or more, more preferably 30,000 or more. The upper limit of the number average molecular weight is not particularly limited, but it is preferably 200,000 or less from the viewpoint of improving the moldability of the resin containing or reacting it.

According to the above-mentioned production method of the present invention, polymethacrylate having a functional group at one end can be produced with a high functional group introduction rate even when the number average molecular weight is high. It is suitable as a method for producing the polymethacrylate of the present invention.

In the production method of the present invention, a radical polymerizable monomer containing methacrylate as a main component is used.
The methacrylate has the general formula

[0026]

CH ₂ ═C (CH ₃ ) (COOR ² ) (III)

(Wherein R ² is as defined above)

Those represented by are preferred. Preferable examples of the methacrylate include alkyl methacrylate such as methyl methacrylate, ethyl methacrylate, n-butyl methacrylate and t-butyl methacrylate; cycloalkyl methacrylate such as cyclohexyl methacrylate; aralkyl methacrylate such as benzyl methacrylate. Methacrylate is
Only one type may be used, or two or more types may be used. In addition to the above-mentioned methacrylate, methyl acrylate, ethyl acrylate, n-butyl acrylate, t
It is also possible to use a small amount of acrylate such as -butyl acrylate (preferably 10 mol% or less based on methacrylate).

In the production method of the present invention, as the functional group-containing mercaptan compound chain transfer agent, a mercaptan compound having at least one functional group such as amino group, carboxyl group and hydroxyl group in the molecule can be used. . In the case of producing the polymethacrylate of the present invention, as a functional group-containing mercaptan compound-based chain transfer agent, a general formula

[0030]

## STR00005 ## HS-R ¹ (-Z ¹ ) (-Z ² ) (IV)

(Wherein R ¹ , Z ¹ and Z ² are as defined above)

A mercaptan compound represented by or a salt thereof may be used. Examples of the mercaptan compound represented by the general formula (IV) or a salt thereof include a mercaptan compound containing one carboxyl group such as mercaptoacetic acid, 2-mercaptopropionic acid, and 3-mercaptopropionic acid; 2-aminoethanethiol hydrochloride A mercaptan compound containing one amino group such as a salt or a salt thereof; a mercaptan compound containing one hydroxyl group such as 2-mercaptoethanol; a mercaptan compound containing two carboxyl groups such as thiomalic acid; thioglycerin Examples thereof include mercaptan compounds having two hydroxyl groups.

In the production method of the present invention, as the azo compound-based polymerization initiator, those usually used in radical polymerization of methacrylate can be used. Typical examples thereof are 2,2'-azobisisobutyronitrile (hereinafter abbreviated as AIBN), 1,1'-azobis (cyclohexane-1-carbonitrile) (hereinafter V-
Abbreviated as 40). The azo compound-based polymerization initiators may be used alone or in combination of two or more. When an azo compound having a functional group (amino group, carboxyl group, hydroxyl group, etc.) such as azobiscyanovaleric acid as described in JP-B-43-11224 is used as a polymerization initiator, It is better not to use an azo compound having a functional group because a methacrylate having a functional group at both ends is easily produced.

The radical polymerization of methacrylate according to the production method of the present invention is preferably carried out at a temperature in the range of 50 to 120 ° C., although it depends on the kind of the initiator and the like.
Regarding the polymerization method, it is preferable to carry out in a homogeneous system by a solution polymerization method or a bulk polymerization method. Furthermore, the reaction system is
In order to make the contact conditions of the methacrylate, the chain transfer agent and the polymerization initiator and the temperature conditions uniform in the system, it is preferable to carry out sufficient stirring. When the solution polymerization method is adopted, the solvent used may be a solvent which can dissolve the monomer, the chain transfer agent and the polymethacrylate to be formed, and is substantially inert with respect to the radical reaction,
For example, benzene, toluene, xylene, N, N-dimethylformamide (hereinafter abbreviated as DMF), methyl ethyl ketone and the like can be mentioned. Among these solvents, it is preferable to use toluene or DMF depending on the solubility of the chain transfer agent. As the polymerization operation, any of batch operation, semi-batch operation and continuous operation can be adopted. Therefore, the methacrylate, the chain transfer agent, and the polymerization initiator may be charged into the reaction system all at once at the start of the polymerization, and at least a part of them may be added during the polymerization in order to control the heat generation and the concentration of the reaction species accompanying the polymerization. It may be continuously or intermittently supplied to the reaction system.

In the production method of the present invention, radical polymerization of methacrylate is carried out for substantially the entire period of the polymerization reaction.
It is important to carry out under the conditions that satisfy the above formula (A). The concentration of the azo compound-based polymerization initiator represented by C in the formula (A) is calculated by the formula

[0036]

[Equation 3] dC / dt = -kd · C + F (t) (B)

(In the formula, t is the elapsed time from the start of polymerization (s
ec), F (t) represents the supply rate (mol / liter · sec) of the azo compound-based polymerization initiator at time t, dC / dt represents the differential value of C with respect to t, and C and kd are the above-mentioned values. As defined)

At the start of polymerization (t
= 0), the concentration of the azo compound-based polymerization initiator (C = C
_It can be obtained by solving ₀ ) as an initial condition. For example, when the polymerization reaction is carried out at a constant temperature while continuously supplying the azo compound-based polymerization initiator to the reaction system at a constant rate F ₁ (mol / liter · sec) from the start of the polymerization, kd is Since it becomes a constant value, C is a mathematical formula

[0039]

[Equation 4] C = (C ₀ −F ₁ / kd) · exp (−kd · t) + F ₁ / kd (C)

(In the formula, exp () represents an exponential function, and C,
(C ₀ , F ₁ , kd and t are as defined above)

It is represented by Further, when the polymerization is started in a state where all the amount of the azo compound-based polymerization initiator is charged into the reaction system at a time and the polymerization is carried out at a constant temperature, the differential equation represented by the mathematical formula (B) is given by F (t ) = 0 condition, k
By solving under the condition of d = constant value and C = C ₀ at t = 0, C is given by

[0042]

[Formula 5] C = C ₀ · exp (-kd · t) (D)

Where C, C ₀ , exp (), kd and t
Is as defined above)

It is represented by As described above, when the polymerization is started in a state where the entire amount of the azo compound-based polymerization initiator is charged at one time and the polymerization is carried out at a constant temperature, C is monotonic with time as apparent from the formula (D). Polymerization conditions such that the initial concentration (C ₀ ) of the azo compound-based polymerization initiator satisfies the above mathematical formula (A) because the maximum value of C decreases to C ₀ .
That is, C ₀ is a mathematical formula

[0045]

[Equation 6] C ₀ · kd ≦ 5 × 10 ⁻⁸ (E)

(Wherein C ₀ and k d are as defined above)

Polymerization conditions satisfying the above condition may be adopted. In this case, the minimum value of C is the concentration at the end of the polymerization and can be calculated based on the above mathematical expression (D).

Kd in each of the above formulas represents the initiation reaction rate constant of the azo compound-based polymerization initiator at the temperature employed in radical polymerization. kd, in part, edited by J. Brandrup and EH Immergut, “Polymer
Handbook (Polymer Handbook), 3rd Edition [John ・
John Wiley and Sons
(USA), 1989], pages II / 3 and II /
It is described on page 6 and the like. For example, in the above polymer handbook, AIBN kd is 2.085 × 10 ⁻⁶ / sec at 50 ° C. and 8.45 × 10 at 60 ° C.
^-6 / sec, 3.166 x 10 ^-5 / sec at 70 ° C, 7
It is 8.023 × 10 ⁻⁵ / sec at 8 ° C. and 1.01 × 10 ⁻⁵ / sec at 80 ° C. for Vd kd of 80.
2.01 × 10 ⁻⁵ / sec at 5 ° C., 3.89 × at 90 ° C.
It is described that at 10 ^-5 / sec, 95 ℃ is 6.83 × 10 ^-5 / sec. Further, since the polymerization initiation reaction by the azo compound-based polymerization initiator generally follows a primary reaction,
It is also possible to experimentally determine kd by examining the change over time in the concentration of the polymerization initiator at a given temperature. That is, experimentally obtained data is plotted on a graph in which the horizontal axis represents the reaction time t (sec) and the vertical axis represents the natural logarithm of the concentration C (mol / liter) of the polymerization initiator in the reaction system. . The absolute value of the slope of the straight line obtained in this way is kd to be obtained. When two or more azo compound-based polymerization initiators are used, the sum of C · kd for each azo compound-based polymerization initiator may be adopted as C · kd in the formula (A).

When the value of C · kd is larger than 5 × 10 ⁻⁸ mol / liter · sec, the number average molecular weight of the obtained polymethacrylate is low, the rate of functional group introduction is low, or their Both will be. For the purpose of obtaining polymethacrylate in which both the number average molecular weight and the functional group introduction rate are particularly high, the value of C · kd is 5 × 10 ⁻⁹ mo
It is preferably 1 / liter · sec or less. From the viewpoint of reachable number average molecular weight and functional group introduction rate,
There is no particular restriction as to the lower limit of the C · kd, progress of the polymerization reaction and the value of C · kd is too low is slow, since the yield of the polymethacrylate is lower than 5 × 10 ^-10 mol / l · sec It is practical not to make it smaller.

From the reaction mixture obtained after the polymerization reaction,
Separation and purification of polymethacrylate having a functional group at one end can be carried out according to a conventional method, for example, by the following method. That is, the reaction mixture is a poor solvent for polymethacrylate, as well as methacrylate,
Impurities such as unreacted methacrylate, chain transfer agent, and polymerization initiator are dissolved and removed by adding them to a solvent that is a good solvent for the chain transfer agent and polymerization initiator (eg, methanol). As a precipitate, polymethacrylate having a desired functional group at one end can be obtained. If necessary, the obtained precipitate may be subjected to post-treatment such as dehydrochlorination treatment.

According to the production method of the present invention, polymethacrylate having a high number average molecular weight can be obtained. Therefore, separation and purification from the reaction mixture can be carried out very efficiently by the above-mentioned simple method. It will be possible. From the viewpoint of high efficiency of this separation / purification, the number average molecular weight of the obtained polymethacrylate is preferably 20,000 or more, more preferably 25,000 or more,
It is particularly preferably 30,000 or more.

Since the polymethacrylate of the present invention has a high functional group introduction rate and a high number average molecular weight, it has high reactivity and suppresses gelation when used as a macromonomer, and further has a polymer blend alloy. The effect of good melt-kneading with other polymers for the purpose of reactive processing and the like is exhibited. Also,
According to the production method of the present invention, polymethacrylate represented by the polymethacrylate of the present invention, which has a high number of functional groups and a high number average molecular weight, can be easily produced.

[0053]

EXAMPLES The present invention will be described more specifically below based on examples, but the present invention is not limited to these examples.

In the following examples and comparative examples, "parts" are parts by weight. The molecular weight of the polymer is GP
Adopting a standard polystyrene-equivalent molecular weight measured by C, and introducing the functional group from the number average molecular weight (hereinafter abbreviated as Mn) and the functional group content per unit weight of the polymer obtained by the neutralization titration method. The rate was calculated.

In Examples and Comparative Examples, the polymerization was started in a state where all the amount of the azo compound-based polymerization initiator was charged at one time, and the polymerization was carried out at a constant temperature. The initiation reaction rate kd of the polymerization initiator becomes a constant value, and the concentration C of the azo compound-based polymerization initiator C
Is the concentration at the beginning of the polymerization (C ₀ ) and the minimum value is the concentration at the end of the polymerization, according to the mathematical formula (D). Therefore, the maximum value (value at the start of polymerization) and the minimum value (value at the end of polymerization) of C · kd are represented by the formula (D) in the azo compound-based polymerization initiator described in the Polymer Handbook. It was calculated by substituting k d of, and C ₀ calculated from the polymerization conditions.

Example 1 Methyl methacrylate (hereinafter abbreviated as MMA) 20
Part, 2-aminoethanethiol hydrochloride (hereinafter referred to as AET.
Abbreviated as HCl) 0.23 parts, AIBN 0.003
Charge 3 parts and 30 parts of DMF into a glass flask,
Degassed by freeze. After introducing nitrogen gas, the flask is set to 60
It was immersed in an oil bath at 0 ° C., and radical polymerization was carried out for 24 hours while stirring the solution. After the reaction was completed, the obtained reaction mixture was poured into a large amount of methanol to reprecipitate the polymer and collect it. The obtained polymer was dissolved in acetone and then reprecipitated in a large amount of dilute aqueous ammonia to dehydrochlorinate the amino group. The treated polymer was again dissolved in acetone, purified by reprecipitation in a large amount of methanol, and vacuum-dried at 70 ° C. to obtain a white powdered purified polymer (polymethyl methacrylate having an amino group at one end). ) Was obtained (the yield of the purified polymer was 36%). M of the obtained purified polymer
n was 35300, and the weight average molecular weight (hereinafter abbreviated as Mw) was 57600. In addition, ¹ H-NMR spectrum analysis (solvent: CDC indicates that the purified polymer is polymethylmethacrylate having an amino group at one end.
In l _3), the peak of α- methyl methyl methacrylate in the component of polymethyl methacrylate chains Deruta0.9～1.2, methylene group methyl methacrylate in the component of polymethyl methacrylate chains δ1.8~2.1 Peak, the peak of the methyl group of the methyl ester portion in the methyl methacrylate component of the polymethylmethacrylate chain at δ3.6, and the 2-aminoethylthio group at δ2.4 to 3.1 (represented by the above general formula (I)). The peak of the methylene group in (corresponding to the group) was observed, and it was calculated from the amount of amino groups quantified by titrating the acetone solution of the purified polymer with the acetic acid solution of perchloric acid and the above Mn value. It was confirmed that the introduction rate of the functional group (amino group) was 83%. C · k at the start and end of polymerization
The respective values of d are shown in Table 1 below together with the functional group introduction ratio and Mn in the obtained polymethyl methacrylate.

Comparative Example 1 20 parts of MMA, 0.23 parts of AET · HCl, AIB
A glass flask was charged with 0.33 part of N and 30 parts of DMF and freeze-deaerated. After introducing nitrogen gas, the flask was immersed in an oil bath at 60 ° C., and radical polymerization was carried out for 8 hours while stirring the solution. Thereafter, the same operation as in Example 1 was performed to obtain 18 parts of a white powdery purified polymer (yield of the purified polymer was 90%). M of the obtained purified polymer
n was 16600 and Mw was 32700. However, the introduction rate of functional groups (amino groups) in the purified polymer is 2
It was found that the amount of the purified polymer was only 7%, and in addition to the molecule of polymethylmethacrylate having an amino group at one end, a large amount of the molecule of polymethylmethacrylate having no amino group was contained. The respective values of C · kd at the start of polymerization and at the end of polymerization are shown in Table 1 below together with the introduction rate of functional groups and Mn in the obtained polymethylmethacrylate.

Example 2 20 parts of MMA, 0.23 part of AET · HCl, V-4
0.0049 parts of 0 and 30 parts of DMF were charged into a glass flask and freeze-deaerated. After introducing nitrogen gas,
The flask was immersed in an oil bath at 80 ° C., and radical polymerization was carried out for 24 hours while stirring the solution. Thereafter, the same operation as in Example 1 was performed to obtain 10.6 of a white powdered purified polymer (polymethyl methacrylate having an amino group at one end).
Parts were obtained (yield of purified polymer was 53%). The purified polymer obtained had Mn of 40300 and Mw of 75700.
Met. ¹ H-NMR spectrum analysis and titration were conducted in the same manner as in Example 1 (the introduction ratio of the functional group (amino group) was 82).
%), And it was confirmed that the purified polymer was polymethylmethacrylate having an amino group at one end. The respective values of C · kd at the start of polymerization and at the end of polymerization are shown in Table 1 below together with the introduction rate of functional groups and Mn in the obtained polymethylmethacrylate.

Comparative Example 2 20 parts of MMA, 0.34 part of AET · HCl, V-4
0.098 parts of 0 and 30 parts of DMF were charged into a glass flask and freeze-deaerated. After introducing nitrogen gas, the flask is immersed in an oil bath at 80 ° C., and the solution is stirred with stirring 1
Radical polymerization was carried out for 5 hours. Thereafter, the same operation as in Example 1 was performed to obtain 18.6 parts of a white powdered purified polymer (yield of the purified polymer was 93%). The molecular weight of the obtained purified polymer was 15600 for Mn and 29700 for Mw.
Met. However, the introduction rate of the functional group (amino group) of the purified polymer is only 61%, and the purified polymer has a molecule of polymethylmethacrylate having no amino group in addition to a molecule of polymethylmethacrylate having an amino group at one end. It was found to contain a large amount. The respective values of C · kd at the start of polymerization and at the end of polymerization are shown in Table 1 below together with the introduction rate of functional groups and Mn in the obtained polymethylmethacrylate.

Example 3 25 parts of MMA, 0.27 of 3-mercaptopropionic acid
Parts, 0.0041 parts of AIBN and 23 parts of toluene were charged into a glass flask and freeze-deaerated. After introducing nitrogen gas, the flask was immersed in an oil bath at 60 ° C., and radical polymerization was carried out for 24 hours while stirring the solution. After the reaction was completed, the obtained reaction mixture was poured into a large amount of methanol,
The polymer was reprecipitated and recovered. The obtained polymer was dissolved in acetone, purified by reprecipitation in a large amount of methanol, and vacuum dried at 70 ° C. to obtain a white powdered purified polymer (polymethyl methacrylate having a carboxyl group at one end). ) Was obtained (the yield of the purified polymer was 42%). The molecular weight of the resulting purified polymer was 21300 for Mn and 3750 for Mw.
It was 0. Further, the purified polymer is polymethylmethacrylate having a carboxyl group at one end,
^{In 1} H-NMR spectrum analysis (solvent: CDCl ₃ ), a peak of α-methyl group in the methyl methacrylate component of the polymethyl methacrylate chain was found at δ 0.9 to 1.2.
.delta.1.8 to 2.1, the peak of the methylene group in the methyl methacrylate component of the polymethylmethacrylate chain, .delta.3.
6 is the peak of the methyl group of the methyl ester portion in the methyl methacrylate component of the polymethyl methacrylate chain, and δ 2.2-3 is the methylene group in the 2-carboxyethylthio group (corresponding to the group represented by the general formula (I)). Of the functional group (carboxyl group) calculated from the amount of the carboxyl group quantified by titrating the acetone solution of the purified polymer with a methanol solution of sodium methoxide and the above Mn value. Introduction rate is 8
It was confirmed from 6%. The respective values of C · kd at the start of polymerization and at the end of polymerization were determined by introducing the functional group introduction ratio and M in the obtained polymethylmethacrylate.
It is shown in Table 1 below together with n.

Comparative Example 3 25 parts of MMA, 0.27 of 3-mercaptopropionic acid
Parts, 0.082 parts of AIBN and 23 parts of toluene were charged into a glass flask and freeze-deaerated. After introducing nitrogen gas, the flask was immersed in an oil bath at 60 ° C., and radical polymerization was carried out for 20 hours while stirring the solution. Thereafter, the same operation as in Example 3 was performed to obtain 2 parts of the white powdered purified polymer.
3 parts were obtained (yield of purified polymer was 92%). The molecular weight of the obtained purified polymer was 14300 for Mn and 27 for Mw.
It was 500. However, the introduction rate of the functional group (carboxyl group) of the purified polymer is only 62%, and the purified polymer contains a large amount of polymethylmethacrylate molecules having no carboxyl in addition to the polymethylmethacrylate molecule having a carboxyl group at one end. Was found to be contained in. C at the start of polymerization and at the end of polymerization
The respective values of kd are shown in Table 1 below together with the functional group introduction ratio and Mn in the obtained polymethyl methacrylate.

Comparative Example 4 20 parts of MMA, 1.45 parts of AET · HCl, AIB
A glass flask was charged with 0.30 part of N and 45 parts of DMF and freeze-deaerated. After introducing nitrogen gas, the flask is immersed in an oil bath at 60 ° C., and the solution is stirred with stirring.
The radical polymerization was carried out for an hour. After completion of the reaction, the obtained reaction mixture was poured into methanol to try to reprecipitate the polymer in the same manner as in Example 1. However, the solubility of the obtained polymer was similar to that of MMA and the like, so that it became cloudy. Almost no precipitate was formed. Therefore, the mixture of the above reaction mixture and methanol was concentrated by an evaporator, and the obtained concentrate was poured into diethyl ether. Water was added to the obtained white viscous substance and the mixture was sufficiently stirred to form a powdery substance, which was vacuum dried at 70 ° C. to obtain 14 parts of a white powdery polymer (polymer yield Is 70%). C at the start of polymerization and at the end of polymerization
The respective values of kd are shown in Table 1 below together with Mn in the obtained polymethylmethacrylate. The obtained polymethylmethacrylate could not be sufficiently purified, and the unreacted chain transfer agent remained, so that the rate of introduction of the functional group could not be determined.

[0063]

[Table 1]

From Table 1 above, C · kd during polymerization
In Examples 1 to 3 according to the present invention, in which the maximum value (value at the initiation of polymerization) was 5 × 10 ⁻⁸ mol / liter · sec or less and the polymerization was carried out under the conditions satisfying the formula (A). It can be seen that a polymethacrylate having a high functional group introduction rate (70% or more) and a high number average molecular weight (20,000 or more) and having a functional group at one end was obtained. On the other hand, C · kd during the entire polymerization period or during the halfway period
Was larger than 5 × 10 ⁻⁸ mol / liter · sec, and the polymerization was carried out under the condition that the formula (A) was not satisfied.
In Comparative Examples 1 to 3 other than the present invention, it is understood that the obtained polymethacrylate has a low functional group introduction rate and a low number average molecular weight. Similarly, in Comparative Example 4 other than the present invention in which the polymerization was carried out under the condition that the formula (A) was not satisfied, the number average molecular weight of the obtained polymethacrylate was low, and simple separation / purification such as reprecipitation was performed. It turns out that adopting the law is difficult.

[0065]

INDUSTRIAL APPLICABILITY The polymethacrylate of the present invention has a functional group introduction rate of 70% or more and a number average molecular weight of 20,000 or more, so that the polymethacrylate molecule having a functional group only at one end of the main chain of the molecule has high purity, And the melt viscosity is moderately high. Therefore, the polymethacrylate is useful as a macromonomer, and is used alone or in the form of a block or graft copolymer obtained by reacting with another polymer having a functional group, as a resin modifier or phase modifier. It is preferably used as a solubilizer.

According to the production method of the present invention, a polymethacrylate having a high functional group introduction rate and a high number average molecular weight, such as the polymethacrylate of the present invention, can be easily obtained. Furthermore, according to the production method, the number average molecular weight of the obtained polymethacrylate can be increased, and therefore, it is possible to separate the unreacted monomer and the chain transfer agent by a simple method such as reprecipitation after the reaction. , Purification becomes easy.

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Claims (2)

(57) [Claims] 1. A main chain is composed of a substantially linear polymethacrylate chain, and one end of the main chain has the general formula: --S--R ¹ (--Z ¹ ) (-Z ² ) ( I) (in the formula, R ¹ represents a trivalent hydrocarbon group, Z ¹ represents an amino group, a carboxyl group or a hydroxyl group, and Z ² represents a hydrogen atom, an amino group, a carboxyl group or a hydroxyl group). A polymethacrylate having a number average molecular weight of 20,000 or more containing 0.7 to 1 group per molecule on average. 2. When radically polymerizing methacrylate in the presence of a functional group-containing mercaptan compound chain transfer agent and an azo compound polymerization initiator, the concentration C of the azo compound polymerization initiator is expressed by the following formula: kd ≦ 5 × 10 ⁻⁸ (A) (where C is the concentration of the azo compound-based polymerization initiator (mol /
Liter), and kd represents radical polymerization under conditions satisfying the initiation reaction rate constant (1 / sec) of the azo compound-based polymerization initiator under the same temperature conditions as the above radical polymerization. And a method for producing a polymethacrylate having a functional group at one end.