JP2000128911A - Catalyst for bulk polymerization and bulk polymerization using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform bulk polymerization at high yield in the presence of one- component catalyst without runaway reaction. SOLUTION: This catalyst for bulk polymerization of polymerizable unsaturated compounds comprises a compound having both (A) at least one of a thiol group expressed by the formula [wherein, R1-R5 are each H or an alkyl; R6 is hydroxyl, an alkyl or the like] and (B) a secondary hydroxyl group. This bulk polymerization of polymerizable unsaturated compounds is carried out in an inert gas in the presence of the above compound in the virtual absence of solvents.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a novel catalyst used for bulk polymerization of a polymerizable compound having a polymerizable double bond and a bulk polymerization method using the catalyst.

[0002]

BACKGROUND OF THE INVENTION Radical polymerization methods for polymerizable compounds having a polymerizable double bond such as acrylic acid, methacrylic acid, and derivatives thereof include emulsion polymerization, suspension polymerization, and solution polymerization. Legal and bulk polymerization processes are known. Among these polymerization methods, emulsion polymerization, suspension polymerization, and solution polymerization are used for dissolving or dispersing a reactive compound in a reaction solvent to carry out the polymerization reaction, so that the polymerization temperature is easily controlled and the polymerization rate is high. There is an advantage that the reaction solution has fluidity even when the temperature is high.

[0003] However, in such emulsion polymerization and suspension polymerization, precipitation is required to remove the polymer from the dispersion medium.
Operations such as filtration, washing, and drying are required, and the process becomes complicated. Moreover, it is difficult for the dispersant or emulsifier used in such a polymerization method to completely separate from the polymer, and the remaining emulsifier or dispersant has properties such as water resistance and strength that the original polymer has, such as water resistance and strength. This may have an adverse effect, and may also adversely affect processing characteristics when mixing, kneading, modifying, etc., these polymers and other materials. Further, in the solution polymerization method, since a large amount of an organic solvent is used, temperature control during the polymerization reaction is easy, and furthermore, for a homogeneous reaction, the polymer can be relatively easily designed. However, there is a problem that a large difference occurs in the monomer concentration between the initial stage and the latter half of the polymerization, the production rate of low molecular weight products is high, and the molecular weight distribution is widened. As a solution to these problems, attempts have been made to solve the above problems by employing a method of dividing and adding a monomer or a method of dropping a monomer. In addition, the convenience of the solution polymerization method that the reaction step is simple is impaired.

The organic solvent used as a reaction solvent in the solution polymerization is generally involved in a polymerization reaction such as a termination reaction or a chain transfer reaction in a polymerization reaction involving chain transfer. This complicates the design of the polymer.

Furthermore, the polymer obtained by solution polymerization contains a large amount of an organic solvent. Therefore, when these polymers are used, it is necessary to remove a large amount of the organic solvent used in the reaction, resulting in low productivity. In addition, when these polymer solutions are used as they are outdoors or the like, there is a problem that the load on the natural environment due to the volatilization of the organic solvent increases.

On the other hand, the bulk polymerization method does not require the use of an organic solvent, a dispersant or an emulsifier because it does not use a solvent, and does not contain impurities such as an organic solvent involved in polymerization. In addition to being simple, the obtained polymer does not contain impurities such as an emulsifier and a dispersant, and further, it is not necessary to remove a solvent to obtain a target polymer. From these points, it is an industrially advantageous polymerization method.

However, in general, such a bulk polymerization method has a remarkably high polymerization reaction rate, and it is practically very difficult to control the bulk polymerization method. In addition, the polymer produced at a high temperature without controlling the polymerization rate was in a state where the terminal group of the molecule became unstable due to the termination of disproportionation, became low molecular weight, or conversely produced earlier Branching or gelling of the polymer is likely to occur due to abstraction of hydrogen from the polymer. For this reason, not only is it difficult to design the molecular weight and molecular weight distribution of the polymer, but also it becomes difficult to design a clear molecular structure due to the branching of the polymer and the generation of the disproportionation termination terminal. Furthermore, rapid and large amounts of gelled material can be formed, and in the worst case, there is even a risk of explosion due to a runaway reaction.

Among these, styrene and methyl methacrylate have the characteristic that the polymerization rate is relatively slow, so that the reaction can be controlled by bulk polymerization, and control methods have been studied for a long time. I have. In such bulk polymerization of styrene and methyl methacrylate, mercaptan may be used to control the molecular weight and the molecular weight distribution.

For example, in the bulk polymerization of a styrene-type unsaturated compound such as styrene in which the reaction proceeds relatively slowly, it is known to perform the bulk polymerization while controlling the progress of the reaction using mercaptan. Specifically, Japanese Patent Publication No. 55-401 discloses that a polymerizable ethylenically unsaturated monomer is reacted at about 20 ° C. to about 200 ° C. in the presence of oxygen.
Contacting with an organic mercaptan having at least one thiol group at a temperature for a time sufficient to obtain substantially complete conversion of the monomer to polymer. Is disclosed. In this reaction,
The presence of oxygen is indispensable, and bulk polymerization of ethylenically unsaturated monomers is performed using mercaptan, the only activator, together with oxygen in the presence of oxygen. Therefore, this reaction does not effectively proceed in an atmosphere where oxygen is not present. In Example 6 of this publication, methacrylic acid, hydroxypropyl methacrylate, butyl acrylate and styrene were introduced at 85 ° C. to 140 ° C. while introducing air using 1-thioglycerol as a mercaptan, substantially It is described that copolymerization is carried out under a temperature condition of 140 ° C. However, in the bulk polymerization described in this publication, mercaptan is used together with oxygen, that is, mercaptan and oxygen are shown as essential components in the initiation of polymerization, and mercaptan alone is used to polymerize an ethylenically unsaturated compound. There is no description about using it as a catalyst. However, when mercaptan and oxygen described in this publication are used as a polymerization catalyst, oxygen is positively blown into the reaction system, so that when implemented in a large plant, there is a large risk of explosion and fire. Further, even if the polymer can be produced safely, there is a problem that the obtained polymer is colored.

[0010] The claims of Japanese Patent No. 2582510 include a method for producing an acrylic polymer by bulk polymerization of a monomer component containing an acrylic acid monomer as a main component. A, wherein the polymerization system in which the bulk polymerization of the monomer components is performed is in an inert gas atmosphere and contains mercaptan, and an acrylic polymer characterized by being substantially free of a polymerization initiator. Manufacturing method. " The role of the mercaptan in the invention described in this publication is one for controlling the molecular weight of the polymer, that is, for controlling the molecular weight and molecular weight distribution, and the other for gently progressing the bulk polymerization of the monomer components to a high polymerization rate. It is stated that this is for moderately controlling the polymerization rate when substantially no initiator is contained. That is, Comparative Example 3 described in paragraph [0032] of this publication is an experimental example in which the reaction was carried out without using 30 parts of octyl thioglycolate, which is a mercaptan used in Example 1, and According to the description, only the polymerizable monomer is heated under a nitrogen atmosphere, and the temperature rises to 130 ° C. 1 hour and 30 minutes after the start of polymerization, so that stable polymerization cannot be performed. The resulting polymer is shown to be gelled. That is, when this Comparative Example 3 was compared with Example 1, the initiation of polymerization was initiated by the heat of the monomer monomer, and the role of the octyl thioglycolate used as the mercaptan was determined by the molecular weight of the polymer. It has been shown that it is used for adjusting the amount of water and suppressing the rapid progress of the reaction in the bulk polymerization reaction.

As described above, in a conventional bulk polymerization reaction of an unsaturated monomer using a mercaptan, mercaptan is used so as to suppress the progress of the bulk polymerization reaction that easily runs away (ie, as a negative catalyst). Used), and there was no technical idea to use this mercaptan as a reaction catalyst for a bulk polymerization reaction of unsaturated monomers.

[0012]

An object of the present invention is to provide a novel catalyst for use in bulk polymerization of a polymerizable unsaturated compound.

In addition, the present invention provides a high polymerization rate and a low molecular weight dispersion index for bulk polymerization of a highly reactive polymerizable unsaturated compound such as an acrylic acid derivative. Another object of the present invention is to provide a novel catalyst for bulk polymerization capable of introducing a hydroxyl group into the obtained polymer.

Further, the present invention provides the use of the above-mentioned catalyst,
It is an object of the present invention to provide a method for performing bulk polymerization of a polymerizable unsaturated compound while reliably controlling the reaction.

[0015]

SUMMARY OF THE INVENTION The present invention resides in a catalyst for bulk polymerization of a polymerizable unsaturated compound, comprising a compound having at least one thiol group and a secondary hydroxyl group represented by the following formula [I].

[0016]

Embedded image

However, in the above formula [I], R ^{1 to} R ⁵
Are each independently a hydrogen atom or an alkyl group having 1 to 12 carbon atoms, and R ⁶ is at least selected from the group consisting of a hydroxyl group, an alkoxy group having 1 to 12 carbon atoms and an alkyl group having 1 to 12 carbon atoms. One type of group.

In the bulk polymerization method of the present invention, at least one thiol group represented by the following formula [I] can be used as a catalyst under an inert gas atmosphere under substantially solvent-free conditions. It is characterized in that a polymerizable unsaturated compound is polymerized using a compound having a hydroxyl group.

[0019]

Embedded image

However, in the above formula [I], R ^{1 to} R ⁵
Are each independently a hydrogen atom or an alkyl group having 1 to 12 carbon atoms, and R ⁶ is at least selected from the group consisting of a hydroxyl group, an alkoxy group having 1 to 12 carbon atoms and an alkyl group having 1 to 12 carbon atoms. One type of group.

The bulk polymerization catalyst of the present invention is a compound having a thiol group (-SH group) and a secondary hydroxyl group in the molecule as shown by the above formula [I]. This formula [I]
By performing bulk polymerization using the compound represented by the above as a catalyst, the bulk polymerization can be stably performed with a narrow molecular weight distribution without runaway of the reaction. In other words, by using a compound having a thiol group and a secondary hydroxyl group in the molecule in this way, even a highly reactive monomer such as acrylic acid or a derivative thereof can be satisfactorily reacted. The polymerization reaction can be performed while controlling. In this reaction, a reaction initiator is not used, and the compound represented by the formula [I] is a reaction catalyst and also a control agent for preventing runaway of the reaction. Therefore, by using the compound represented by the formula [I] as a catalyst for the bulk polymerization reaction, it is not necessary for other reaction initiators such as oxygen to coexist in the reaction system, and further, the bulk polymerization using this compound is not required. In the reaction, it is not necessary to perform two-stage polymerization using another reaction initiator.

Furthermore, by using this compound [I] as a catalyst, runaway of the reaction can be prevented, and a bulk polymerization reaction can be carried out under mild conditions. Is difficult to generate. And
The reaction mechanism in bulk polymerization using this catalyst is not always clear. However, the catalyst produced by using this catalyst has a specific effect of introducing a hydroxyl group into the polymer, and specifically, the polymer produced using this catalyst has a terminal effect on the polymer end. "-SR"
While the ratio of groups such as is extremely increased,
The polymer thus produced has a significant hydroxyl value (OHV value) due to the hydroxyl groups in the catalyst. Further, the catalyst of the present invention is not a negative catalyst for controlling the reaction like a conventional mercaptan, and can proceed a bulk polymerization reaction without using another polymerization initiator. By using the compound to be used, the bulk polymerization reaction can be gently advanced.

[0023]

Next, the bulk polymerization catalyst of the present invention and the bulk polymerization method using the catalyst will be described in detail.

The catalyst of the present invention comprises a compound having at least one thiol group and a secondary hydroxyl group represented by the following formula [I]. This catalyst is used for bulk polymerization using a polymerizable unsaturated compound.

[0025]

Embedded image

However, in the above formula [I], R ^{1 to} R ⁵
Is each independently a hydrogen atom or an alkyl group having 1 to 12 carbon atoms, preferably a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. Specific examples of such an alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, and a pentyl group. Particularly, among them, R ^{1 to} R ⁵ are preferably a hydrogen atom. In the formula [I],
R ⁶ is at least one group selected from the group consisting of a hydroxyl group, an alkoxy group having 1 to 12 carbon atoms and an alkyl group having 1 to 12 carbon atoms. Here, as the alkoxy group,
An alkoxy group having 1 to 4 carbon atoms is preferable, and specific examples include a methoxy group, an ethoxy group, a propoxy group, and a butoxy group. Here, the alkyl group has 1 carbon atom.
Preferred are alkyl groups of 5 to 5, and specific examples include a methyl group, an ethyl group, a propyl group, a butyl group, and a pentyl group. Further, in the present invention, R ⁶ is preferably a hydroxyl group.

Accordingly, in the present invention, as an example of the compound represented by the formula [I], thioglycerol (1-Thiogl
yserol), 1-mercapto-2,3-propanediol, 2-mercapto-3-butanol, 2-mercapto-3,4-butanediol, 1-mercapto-2,3-butanediol, 1-mercapto-2- Butanol, 2-mercapto-3,4,4'-butanetriol, 1-mercapto-3,4-butanediol, 1-mercapto-3,4,4'-butanetriol can be mentioned, these compounds are It is useful as a catalyst for bulk polymerization, and among these, thioglycerol is most useful as a catalyst for bulk polymerization.

The compound represented by the above formula [I] has both a thiol group (-SH) and a secondary hydroxyl group (-OH) in one molecule. In the present invention, in order to use it as a catalyst for bulk polymerization, it is necessary that a thiol group and a secondary hydroxyl group coexist in one molecule. For example, a compound such as octyl thioglycolate, which is conventionally used for bulk polymerization, has a thiol group in one molecule but does not have a hydroxyl group. When a compound having a thiol group but not having a hydroxyl group in such a molecule is allowed to coexist, for example, in the bulk polymerization of an acrylic acid derivative, such a compound suppresses the progress of the reaction, It acts as a negative catalyst on the polymerization reaction, and has little effect of promoting such a bulk polymerization reaction by itself. Therefore, in the catalyst used in the bulk polymerization, it is extremely important that the hydroxyl group present in the molecule is a secondary hydroxyl group. In a compound in which a secondary hydroxyl group and a thiol group coexist in one molecule, it is presumed that the hydrogen atom constituting the thiol group is attracted to the secondary hydroxyl group to start the reaction. The compound used as a catalyst needs to have a thiol group and a secondary hydroxyl group in one molecule.

In the present invention, the compound represented by the formula [I] can be obtained by coexisting the compound represented by the above formula [I] and the polymerizable unsaturated compound under an inert atmosphere such as nitrogen gas or argon gas. The compound represented by the formula serves as a catalyst for promoting the bulk polymerization reaction in the bulk polymerization reaction.
Moreover, even when a polymerizable unsaturated compound such as an acrylate ester, in which the bulk polymerization reaction rate is difficult to control, is used, the bulk of the polymerizable unsaturated compound can be controlled within a range where the reaction rate can be controlled. The polymerization reaction can proceed. In the bulk polymerization using the compound represented by the formula [I] as a catalyst, the presence of oxygen in the reaction system inhibits the original catalytic action of the compound represented by the formula [I].
Therefore, when the compound represented by the formula [I] is used as a catalyst, the reaction system is purged with an inert gas.

Regarding the polymer obtained by performing bulk polymerization using the catalyst of the present invention, regardless of the type of the raw material monomer, the hydroxyl value (O) is probably due to the hydroxyl group of the catalyst used.
HV value). In addition, the molecular terminal of the polymer obtained by bulk polymerization using the compound represented by the above formula [I] has
Very often -SR groups are introduced.

Hereinafter, a bulk polymerization method using the compound represented by the above formula [I] as a catalyst will be described. In the bulk polymerization method of the present invention, a compound having at least one thiol group represented by the following formula [I] and a secondary hydroxyl group as a catalyst under an inert gas atmosphere under substantially solvent-free conditions: Is used to polymerize the polymerizable unsaturated compound.

The compound used as a catalyst in the bulk polymerization method of the present invention is a compound having at least one thiol group and a secondary hydroxyl group represented by the following formula [I].

[0033]

Embedded image

However, in the above formula [I], R ^{1 to} R ⁶
Has the same meaning as described above. The monomer used in the bulk polymerization using the compound is a polymerizable unsaturated compound,
It is a compound having an ethylenic double bond.

Examples of such a polymerizable unsaturated compound include a vinyl group-containing compound. Further, examples of such a polymerizable unsaturated compound include the following compounds.

Salts such as acrylic acid and alkali metal acrylate; salts such as methacrylic acid and alkali metal methacrylate; methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, pentyl acrylate, acrylic acid Hexyl, 2-ethylhexyl acrylate, octyl acrylate, nonyl acrylate,
Alkyl acrylates such as decyl acrylate and dodecyl acrylate; aryl acrylates such as phenyl acrylate and benzyl acrylate; methoxyethyl acrylate, ethoxyethyl acrylate, propoxyethyl acrylate, butoxyethyl acrylate; Alkoxyalkyl acrylates such as ethoxypropyl acrylate; methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate;
Methacrylic alkyl esters such as pentyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, octyl methacrylate, nonyl methacrylate, decyl methacrylate and dodecyl methacrylate; methacrylic acids such as phenyl methacrylate and benzyl methacrylate Aryl acid esters; methoxyethyl methacrylate, ethoxyethyl methacrylate, propoxyethyl methacrylate, butoxyethyl methacrylate, ethoxypropyl methacrylate; alkoxyalkyl methacrylates; diacrylates of ethylene glycol, diacrylates of diethylene glycol, triacrylate Ethylene glycol diacrylate, polyethylene glycol diacrylate, propylene glycol diacrylate (Poly) alkylene glycol diacrylates such as acid S, dipropylene glycol diacrylate, tripropylene glycol diacrylate; ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol Dimethacrylates of (poly) alkylene glycols such as dimethacrylate, polyethylene glycol diacrylate, propylene glycol dimethacrylate, dipropylene glycol dimethacrylate, tripropylene glycol dimethacrylate; Polyacrylates such as trimethylolpropane triacrylate; trimethylolpropane trimethacrylate Polyhydric methacrylates such as acid esters; acrylonitrile; methacrylonitrile; vinyl acetate; vinylidene chloride; vinyl halide compounds such as -2-chloroethyl acrylate and -2-chloroethyl methacrylate; Acrylic ester of alicyclic alcohol; Methacrylic ester of alicyclic alcohol such as cyclohexyl methacrylate; 2-vinyl-2-oxazoline, 2-vinyl-5-methyl-2-oxazoline, 2-isopropenyl-2 An oxazoline group-containing polymerizable compound such as -oxazoline; acryloylaziridine, methacryloylaziridine, 2-aziridinylethyl acrylate,
Aziridine group-containing polymerizable compound such as 2-aziridinylethyl methacrylate; allyl glycidyl ether, glycidyl acrylate, glycidyl methacrylate, glycidyl acrylate, acrylic acid
Epoxy group-containing vinyl monomers such as 2-ethyl glycidyl ether and methacrylic acid-2-ethyl glycidyl ether; 2-hydroxyethyl acrylate, methacrylic acid-2-
Contains hydroxyl groups such as hydroxyethyl, 2-hydroxypropyl acrylate, monoester of acrylic acid or methacrylic acid with polypropylene glycol or polyethylene glycol, adducts of lactones with 2-hydroxyethyl (meth) acrylate Vinyl compounds; fluorinated vinyl monomers such as fluorinated alkyl methacrylates and fluorinated alkyl acrylates; unsaturated carboxylic acids such as itaconic acid, crotonic acid, maleic acid and fumaric acid, excluding (meth) acrylic acid Acids, salts thereof, and (partially) ester compounds and acid anhydrides thereof; reactive halogen-containing vinyl monomers such as 2-chloroethyl vinyl ether and vinyl monochloroacetate; methacrylamide, N-methylol methacrylamide, N- Methoxyethylmethac Amide group-containing vinyl monomers such as vinylamide, N-butoxymethylmethacrylamide; vinyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, allyltrimethoxysilane, trimethoxysilylpropylallylamine, 2-methoxyethoxytrimethoxy Organic silicon group-containing vinyl compound monomers such as silane; and diene compounds such as ethyldennorbornene, piperidine, isoprene, pentadiene, vinylcyclohexene, chloroprene, butadiene, methylbutadiene, cyclobutadiene and methylbutadiene.

In addition, macromonomers having a radically polymerizable vinyl group at the terminal of a monomer obtained by polymerizing a vinyl group (eg, a fluorine-based monomer, a silicon-containing monomer,
Macromonomer, styrene, silicon, etc.).

These polymerizable unsaturated compounds can be used alone or in combination. These polymerizable unsaturated compounds may be liquid, solid, or gas under the reaction conditions, but are preferably used as liquids for simplicity of operation.

The polymerization method of the present invention is bulk polymerization, and the reaction is carried out under the condition that substantially no solvent is used. Here, “substantially does not use a solvent” means that no reaction solvent is used. For example, in order to uniformly disperse the compound represented by the formula [I] used as a catalyst throughout the monomer. In addition, a solvent used for dissolving or dispersing in a very small amount of a solvent, a solvent remaining in a raw material, and the like are not excluded.

The bulk polymerization reaction of the present invention is performed in an inert gas atmosphere, and therefore, there is no active gas such as oxygen in the bulk polymerization reaction system. Examples of the inert gas used here include a nitrogen gas, an argon gas, a helium gas, and a carbon dioxide gas.

In the bulk polymerization, the compound represented by the above formula [I] used as a catalyst can be used in a usual amount of a catalyst. The thiol group is used in an amount of 0.1 to 50 mol, preferably 0.5 to 35 mol, based on 100. When the number of moles of thiol group is 0.1 or less with respect to the number of moles of unsaturated group of 100, no sufficient initiation effect is observed, and the unsaturated group is particularly stable as in a styrene type unsaturated compound. It is preferable to use 0.5 moles or more of thiol group moles per 100 moles of unsaturated groups. When the mole number of the thiol group is 50 moles or more with respect to the mole number of the unsaturated group of 100, a sudden addition reaction occurs preferentially to the polymerizable unsaturated compound, and a polymer having a sufficient degree of polymerization is obtained. Not only cannot be obtained, but also it is difficult to maintain the reaction due to remarkable heat generation. Also,
Like acrylate-based polymerizable unsaturated compounds,
When a compound having a high activity of an unsaturated group is used, and when the number of moles of a thiol group is 35 or more with respect to 100 moles of an unsaturated group, remarkable heat generation occurs due to a sudden reaction, and it becomes difficult to maintain the reaction.

When the compound represented by the formula [I] is used alone, the bulk polymerization of the polymerizable unsaturated compound proceeds well, but in addition to the compound represented by the formula [I], Alternatively, a conventionally used reaction initiator can be used in combination. Even when such a reaction initiator is used in combination, the bulk polymerization of the present invention proceeds smoothly without runaway.

The bulk polymerization reaction can be carried out with heating, heating or cooling, depending on the type of the polymerizable unsaturated compound. It is preferable to set within the range of ° C, and it is especially preferable to set within the range of 25 to 120 ° C. By setting the bulk polymerization reaction temperature within the above range, the compound represented by the formula [I] can function efficiently as a positive catalyst. Depending on the activity of the unsaturated group of the polymerizable unsaturated compound used, even when a relatively polymerizable acrylate-based polymerizable unsaturated compound is used, when the reaction temperature is 0 ° C or lower, The activity of the compound represented by the formula [I] as a catalyst decreases, and the time required to obtain a sufficient polymerization rate increases,
ineffective. Further, even when a compound having a low polymerization activity such as a styrene-type unsaturated compound is used, a sufficient polymerization rate can be obtained under conditions of 25 ° C. or higher. When the reaction temperature is 150 ° C. or higher, depending on the activity of the polymerizable unsaturated compound, acrylate-type unsaturated compounds and the like also cause polymerization by thermal initiation,
In addition to the polymer produced by using the compound represented by the formula [I] as a catalyst, a polymer produced by thermal initiation is included, so that not only the desired polymer cannot be obtained, but also a runaway reaction due to significant heat generation during the polymerization reaction. Danger. Polymerization temperature 12
By setting the temperature at 0 ° C. or lower, a polymer produced by the catalytic action of the compound represented by the formula [I] can be efficiently obtained, and the progress of the reaction can be maintained without runaway of the reaction. .

The bulk polymerization reaction using the compound represented by the formula [I] of the present invention as a catalyst is described using thioglycerol (3-mercapto-1,2-propanediol) as an example. Although it is not possible, it is estimated that the process proceeds as follows.

[0045]

Embedded image

That is, as shown in the above schematic diagram, in the initial stage, in the thioglycerol having an SH group and a secondary hydroxyl group in the molecule, the hydrogen atom of the thiol group is attracted to the secondary hydroxyl group, and the thio radical (.S It is presumed that the initiation of the initial polymerization reaction occurs due to the formation of a radical) and the addition of the thio radical to the polymerizable unsaturated compound. Next, it is presumed that chain transfer and growth reaction to thioglycerol and the unsaturated compound proceed as described above. The termination of this reaction is presumed to be due to termination of chain transfer to thioglycerol, termination of recombination between growing radicals, and termination of recombination with thioglycerol radicals existing in a thioradical state. In this case, the thioglycerol radical from which hydrogen has been abstracted by chain transfer is again added as a starting terminal with a monomer, or recombines with a growing radical and added to the polymer terminal as a terminator.

Since the thioglycerol introduced into the start terminal and the stop terminal has a hydroxyl group, a hydroxyl group is introduced into the molecular terminal of the polymer produced by the method of the present invention. That is, in the case of thioglycerol, the molecule has two hydroxyl groups in the molecule, and the resulting polymer has a molecular structure in which two or four hydroxyl groups are introduced at the start end, or at the start and stop ends. A polyfunctional hydroxyl group-containing polymer having the same is obtained.

Therefore, the polymer obtained by the bulk polymerization method of the present invention has a hydroxyl group derived from the compound represented by the formula [I], and the specific hydroxyl group value (OHV) depends on the type and amount of the catalyst used. Value). The hydroxyl group thus introduced into the molecular terminal has the same reactivity as a normal hydroxyl group, for example, it can react with a compound having an isocyanate group to have a urethane bond, It can also react with chloride groups and carboxyl groups and have an ester bond. Therefore, the polymer obtained by the bulk polymerization method of the present invention easily reacts with a polyfunctional compound having a functional group capable of reacting with a hydroxyl group to form a crosslinked structure.

By using the compound represented by the formula [I] as a catalyst as described above, the reaction rate of this bulk polymerization is usually at least 50%, preferably at least 70%.
In spite of the high reaction rate, the use of the compound represented by the formula [I] as a catalyst makes it possible to use a highly reactive polymerizable unsaturated compound such as an acrylate ester. Even if it does, the reaction does not run away and the bulk polymerization reaction can be stably performed.

The bulk polymer (including the composition) produced as described above varies depending on the type of the polymerizable unsaturated compound used and the type and amount of the catalyst represented by the formula [I]. The average molecular weight is usually 500 to 10,000
0, preferably in the range of 1000-10000,
The weight average molecular weight is usually in the range of 1,000 to 300,000, preferably 1,000 to 100,000.

The bulk polymer thus obtained is purified, if necessary, and used in the same manner as a usual polymer.

[0052]

Industrial Applicability The bulk polymerization catalyst of the present invention can be effectively used as a bulk polymerization catalyst for polymerizable unsaturated compounds. The bulk polymerization catalyst can perform bulk polymerization under mild conditions without runaway without using oxygen or other polymerization initiators. further,
By using the bulk polymerization catalyst of the present invention, a polymer can be obtained in high yield. Moreover, by using this catalyst, a hydroxyl group can be introduced into at least a part of the molecules of the obtained copolymer.

Further, according to the polymerization method of the present invention, even when a highly reactive compound such as an acrylate is used, which has conventionally been difficult to control the reaction in bulk polymerization due to a high reaction rate. The reaction can be performed smoothly without runaway.

Furthermore, according to the bulk polymerization of the present invention, it is possible to introduce a hydroxyl group into the molecular terminal of the obtained polymer.

[0055]

Next, the present invention will be described in more detail by way of examples, but the present invention is not limited to these examples.

[0056]

Example 1 A flask equipped with a stirrer, a nitrogen gas inlet tube, a thermometer and a reflux condenser was charged with butyl acrylate.
Then, nitrogen gas was introduced into the flask, and the air in the flask was replaced with nitrogen gas. further,
The contents of the flask were slowly heated to a temperature of 60 ° C. while introducing nitrogen gas.

Then, as a catalyst, 5 parts by weight of thioglycerol sufficiently substituted with nitrogen gas was added to the flask with stirring. After the addition of thioglycerol, the reaction was carried out for 4 hours while cooling and heating so that the temperature inside the flask during stirring was maintained at 60 ° C.

After 4 hours, the temperature of the reaction product was returned to room temperature, and 20 parts by weight of a benzoquinone solution (a solution in which benzoquinone was diluted to 5% by weight with THF) was added to the reaction product to terminate the polymerization.

With respect to the THF solution of the thus obtained reaction product, the amount of the remaining monomer was measured by gas chromatography to determine the degree of polymerization. As a result, the conversion was 75
%, And no runaway of the polymerization reaction was observed during the polymerization.

[0060]

Example 2 After replacing the inside of a flask equipped with a stirrer, nitrogen gas inlet tube, thermometer and reflux condenser with nitrogen gas, the flask was charged with 1200 parts by weight of ethyl methacrylate, 225 parts by weight of methyl methacrylate, and methacrylic acid. 75 parts by weight of hydroxyethyl acid and 16 parts by weight of thioglycerol were charged and stirred. The mixture was heated to 70 ° C. with stirring while gently blowing nitrogen gas through the mixture. Polymerization was continued at this temperature for 4 hours.

After 4 hours, the temperature of the reaction product was returned to room temperature, and the benzoquinone solution used in Example 1 was added to the reaction product for 1 hour.
The polymerization was stopped by adding 0 parts by weight. With respect to the THF solution of the reaction product thus obtained, the residual amount of the monomer was measured by gas chromatography to determine the conversion.
As a result, the polymerization rate was 60%, and no runaway of the polymerization reaction was observed at the time of the above polymerization.

[0062]

Example 3 Ethyl acrylate 1 was placed in a flask equipped with a stirrer, a nitrogen gas inlet tube, a thermometer and a reflux condenser.
Then, nitrogen gas was introduced into the flask, and the air in the flask was replaced with nitrogen gas. further,
The contents of the flask were slowly heated to a temperature of 75 ° C. while introducing nitrogen gas.

Next, as a catalyst, 8 parts by weight of thioglycerol sufficiently substituted with nitrogen gas was added to the flask with stirring. After the addition of thioglycerol, the reaction was carried out for 6 hours while cooling and heating so that the temperature in the flask during stirring was maintained at 75 ° C.

After a lapse of 6 hours, the temperature of the reaction product was returned to room temperature, and 20 parts by weight of a benzoquinone solution (a solution of benzoquinone diluted to 5% by weight with THF) was added to the reaction product to terminate the polymerization.

With respect to the THF solution of the reaction product thus obtained, the amount of the remaining monomer was measured by gas chromatography to determine the conversion. As a result, the conversion was 72
%, And no runaway of the polymerization reaction was observed during the polymerization.

Subsequently, the obtained reaction product was transferred to an evaporator, and while gradually heating to 70 ° C. under reduced pressure,
F and residual monomer and residual thioglycerol were removed. The residue obtained by heating the polymer obtained at 150 ° C. was 9%.
It was 9.7%.

The molecular weight measured by gel permeation chromatography (GPC) was as follows: weight average molecular weight = 4800, number average molecular weight = 2800, dispersion index =
1.7 and a viscosity at 23 ° C of 1190 centipoise (cps). In addition, the hydroxyl value (O
HV: mg / g KOH) was 77.

[0068]

Comparative Example 1 After replacing the inside of a flask equipped with a stirrer, a nitrogen gas inlet tube, a thermometer and a reflux condenser with nitrogen gas, the flask was charged with 1200 parts by weight of ethyl methacrylate, 225 parts by weight of methyl methacrylate, and methacrylic acid. 75 parts by weight of hydroxyethyl acid and 30 parts by weight of octyl thioglycolate were charged and stirred. The mixture was heated to 70 ° C. with stirring while gently blowing nitrogen gas through the mixture. Polymerization was continued at this temperature for 4 hours.

After a lapse of 4 hours, the temperature of the reaction product was returned to room temperature, and the benzoquinone solution used in Example 1 was added to the reaction product for 1 hour.
The polymerization was stopped by adding 0 parts by weight. With respect to the THF solution of the reaction product thus obtained, the residual amount of the monomer was measured by gas chromatography to determine the conversion.
As a result, the conversion was 2%, and the conversion was extremely low.

[0070]

Comparative Example 2 Ethyl acrylate 100 was added to a flask equipped with a stirrer, an air inlet tube, a thermometer, and a reflux condenser.
The weight of the flask was charged, air was blown into the flask, and the contents of the flask were heated to 75 ° C. while filling the flask with air.
Heated slowly to the temperature.

Next, thioglycerol 8 was used as a catalyst.
When parts by weight were added to the flask with stirring, the temperature in the reaction system rapidly increased and the reaction could not be controlled.

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[Procedure amendment]

[Submission date] February 16, 1999 (1999.2.1
6)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0067

[Correction method] Change

[Correction contents]

The molecular weight measured by gel permeation chromatography (GPC) was as follows: weight average molecular weight = 4800, number average molecular weight = 2800, dispersion index =
1.7 and a viscosity at 23 ° C. of 11900 centipoise (cps). The reaction product had a hydroxyl value (OHV: mg KOH / g ) of 77.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08F 22/00 C08F 22/00 26/06 26/06 30/08 30/08 36/04 36/04 F term (reference) 4J011 AA05 AB02 BB02 FA03 FA05 FB05 4J015 EA03 EA05 4J100 AC04P AE18P AG04P AG41P AJ01P AJ02P AJ08P AJ09P AK08P AK31P AK32P AL03P AL04P AL05P AL08P AL09P AL10P AL11P AL62P AL63P AL66P AM02P AM15P AM21P AP16P AQ15P AR16P AS02P AS03P AS04P AS07P AS15P AU21P BA02P BA03P BA04P BA05P BA06P BA08P BA72P BB01P BC04P BC43P BC54P BC64P CA01 FA08 FA18 FA28

Claims (8)

[Claims] 1. A catalyst for bulk polymerization of a polymerizable unsaturated compound, comprising a compound having at least one thiol group and a secondary hydroxyl group represented by the following formula [I]: [However, in the above formula [I], R ^{1 to} R ⁵ are each independently a hydrogen atom or an alkyl group having 1 to 12 carbon atoms, and R ⁶ is a hydroxyl group, an alkoxy group having 1 to 12 carbon atoms and And at least one group selected from the group consisting of alkyl groups having 1 to 12 carbon atoms]. 2. The bulk polymerization catalyst according to claim 1, wherein the compound represented by the formula [I] is thioglycerol. 3. A compound having at least one thiol group and a secondary hydroxyl group represented by the following formula [I] as a catalyst under an inert gas atmosphere under substantially solvent-free conditions. A bulk polymerization method characterized by polymerizing a polymerizable unsaturated compound; [However, in the above formula [I], R ^{1 to} R ⁵ are each independently a hydrogen atom or an alkyl group having 1 to 12 carbon atoms, and R ⁶ is a hydroxyl group, an alkoxy group having 1 to 12 carbon atoms and And at least one group selected from the group consisting of alkyl groups having 1 to 12 carbon atoms]. 4. The compound represented by the formula [I], wherein the number of moles of the thiol group is in the range of 0.5 to 35 moles per 100 moles of the unsaturated group of the polymerizable unsaturated compound. 4. The bulk polymerization method according to claim 3, wherein the bulk polymerization method is used in an amount. 5. The bulk polymerization method according to claim 3, wherein said bulk polymerization reaction is carried out at a temperature in the range of 25 to 120 ° C. 6. The bulk polymerization method according to claim 3, wherein the compound represented by the formula [I] is thioglycerol. 7. The bulk polymerization method according to claim 3, wherein said polymerizable unsaturated compound is a vinyl group-containing compound. 8. The polymerizable unsaturated compound is selected from the group consisting of acrylic acid and salts thereof, methacrylic acid and salts thereof, alkyl acrylate, alkyl methacrylate,
Diacrylate, dimethacrylate, acrylonitrile, methacrylonitrile, vinyl acetate, vinyl halide compounds, vinylidene chloride, acrylates of alicyclic alcohols, methacrylates of alicyclic alcohols, oxazoline group-containing polymerizable compounds, Aziridine group-containing polymerizable compound, epoxy group-containing vinyl monomer, hydroxyl group-containing vinyl compound, unsaturated carboxylic acid (excluding (meth) acrylic acid), salts and esters thereof, unsaturated dicarboxylic acids, salt,
These (partial) ester compounds and acid anhydrides, reactive halogen-containing vinyl monomers, amide group-containing vinyl monomers, organosilicon group-containing vinyl compound monomers, and
8. The bulk polymerization method according to claim 3, comprising at least one kind of polymerizable unsaturated compound selected from the group consisting of diene compounds.