JPH09124746A - Acrylonitrile solution of maleimide and production thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a stable soln. which is clear, does not become colored nor turbid during handling, and exhibits little difference in color between before and after the forced coloration test by dissolving a maleimide in acrylonitrile having a specified water content. SOLUTION: An acrylonitrile soln. of a maleimide (e.g., N-methylmaleimide) having a water content of 0.1wt.% or lower is obtd. by dissolving the maleimide in acrylonitrile having a water content reduced to 0.1wt.% or lower. Thus obtd. soln. exhibits differences in color between before and after the forced coloration test ΔL, Δa, and Δb (defined by formulas, I, II, and III, respectively) of 5 or lower, 5 or lower, and 10 or lower, respectively. Such a soln. can also be prepd. by adding at least one compd. selected from among an alkylated hydroxybenzene., a hindered phenol, a phosphite, a phosphoric ester, and a phosphoramide to an acrylonitrile soln. of a maleimide having a water content adjusted to 0.3wt.% or lower.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an acrylonitrile solution of maleimides, a method for preparing the same, and an acrylonitrile-maleimide-containing copolymer obtained by using the acrylonitrile solution.

[0002]

Maleimides typified by N-phenylmaleimide are acrylonitrile-butadiene-styrene (ABS) resin, acrylonitrile-acrylic rubber-styrene (AAS) resin, acrylonitrile-styrene (AS) resin, acrylonitrile-chlorinated resin. As a heat resistance improver for acrylonitrile-based copolymers such as polyethylene-styrene (ACS) resins, they are widely used for copolymerization with monomers constituting these resins. In the present invention,
The acrylonitrile-based copolymer containing these maleimides is referred to as "acrylonitrile-maleimide-containing copolymer".

Conventionally, maleimides which are solid at room temperature have generally been handled in the form of powder, flakes, tablets and the like. However, such solid maleimides become powdered during the transfer, generate a large amount of fine powder, and cause various problems such as deterioration of the working environment. In order to solve these problems, the present applicant has previously proposed a method for safely and stably handling maleimides in the form of an acrylonitrile solution in the presence of a polymerization inhibitor (Japanese Patent Publication No. Hei.
-12057). This method of handling maleimides in the form of an acrylonitrile solution is currently widely used industrially because it is excellent in solving the above problems.

Furthermore, the applicant of the present invention handles the maleimides as an acrylonitrile solution by adjusting the acid content in the acrylonitrile solution of the maleimides to 0.3% by weight (JP-A-64-61456), A method has been proposed in which the acid content of maleimides in an acrylonitrile solution is adjusted to 0.3% by weight or less and a polymerization inhibitor is allowed to coexist (JP-A-1-250348). These methods make it possible to safely and stably handle the acrylonitrile solution while preventing corrosion of the metal material by the acrylonitrile solution of maleimides.

An acrylonitrile solution of maleimides is
Used in combination with other monomers to produce an acrylonitrile-based copolymer as described above (acrylonitrile as a solvent serves as a source of an acrylonitrile component of this copolymer), but an acrylonitrile solution of a maleimide as a raw material Is colored or becomes cloudy, the resulting acrylonitrile-maleimide-containing copolymer has poor color tone, and its commercial value is significantly impaired. For this reason,
In order to increase the commercial value of such final products,
There is a strong demand for an acrylonitrile solution of maleimides that is clear and has excellent stability without coloring or turbidity during handling, because the criteria or requirements for coloring or clouding of an allonitrile solution of maleimides become more severe.

Although the above-mentioned method for handling an acrylonitrile solution of maleimides has solved the problem to some extent, it has not always been able to sufficiently meet the recent severe requirements as described above.

[0007]

SUMMARY OF THE INVENTION One of the objects of the present invention is to provide an acrylonitrile solution of a maleimide which is clear and has excellent stability without coloring or clouding during its handling.

Another object of the present invention is to provide a method for preparing an acrylonitrile solution of the above maleimides.

Another object of the present invention is to provide an acrylonitrile-maleimide-containing copolymer excellent in color tone, which is obtained by using the acrylonitrile solution of the above maleimides.

The term "handle" in the present invention means
Transport of maleimide acrylonitrile solutions by tank trucks, storage in tanks, pipes including valves, nozzles, etc. (for example, storage tank of maleimide acrylonitrile solution from polymerization supply line) means.

[0011]

The present invention provides a maleimide compound characterized in that the color differences ΔL, Δa and Δb before and after the test by the forced coloring test method are 5 or less, 5 or less and 10 or less, respectively. It relates to an acrylonitrile solution.

[Delta] L = | L value after test−L before test
Value | (absolute value) Δa = | a value after test−a value before test | (absolute value) Δb = | b value after test−b value before test | (absolute value) Relates to a method for preparing the acrylonitrile solution, wherein the water content in the acrylonitrile solution is 0.1% by weight or less.

In the present invention, the acrylonitrile solution contains at least one selected from alkyl-substituted hydroxybenzenes and hindered phenols and at least one selected from phosphites, phosphates and amides. The present invention relates to a method for preparing the above-mentioned acrylonitrile solution, which is characterized in that seeds are present.

In the present invention, the water content in the acrylonitrile solution is set to 0.3% by weight or less, and at least one selected from alkyl-substituted hydroxybenzenes and hindered phenols in the acrylonitrile solution, or phosphorous acid. The present invention relates to a method for preparing an acrylonitrile solution, characterized in that at least one selected from esters, phosphoric acid esters and phosphoric acid amides is present.

The present invention also provides an acrylonitrile-containing compound obtained by using the acrylonitrile solution of the above maleimides.
The present invention relates to a maleimide-containing copolymer.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION The acrylonitrile solution of the maleimides of the present invention is subjected to L.O. a. b. The difference ΔL, Δa and Δb in the values is 5 or less, 5 or less and 10 or less, respectively, and the stability is extremely small with no coloring or clouding. Particularly, ΔL, Δa and Δb are preferably 1 or less, 1 or less and 2 or less, respectively.

Here, L. a. b. The value measuring method and the forced coloring test method are as follows.

L. a. b. Value Using a Σ-80 type color difference meter manufactured by Nippon Denshoku Industries Co., Ltd., the concentration of the acrylonitrile solution of maleimides as a sample was adjusted to 30% by weight, and then the L. a. b. Values were measured in transmission mode. A commercially available acrylonitrile (special grade reagent) was used as a control, and the thickness of the cell used was 10 mm.

Forced coloring test method Pyrex test tube of 18 mm (inner diameter) × 180 mm (height) was charged with an acrylonitrile solution of maleimides as a sample, and then preliminarily polished in this solution 50 mm in length × 10 mm in width × thickness SU with a size of 2 mm
A test piece made of S304 was put in. After adjusting the molecular oxygen concentration in the gas phase part of the test tube to 3 to 10% by volume, the test tube was placed in an oil bath set at 70 ° C. and held for 3 days (72 hours), and then the test piece was taken out. hand,
L. acrylonitrile solution. a. b. The value was measured. However, the molecular oxygen concentration is based on the volume of the gas mixture excluding maleimides and acrylonitrile.

Specific examples of the maleimides used in the present invention include maleimide, N-methylmaleimide, N-ethylmaleimide, N-hexylmaleimide, N-octylmaleimide, N-dodecylmaleimide, N-benzylmaleimide, N-hexylmaleimide. Cyclohexylmaleimide, N-phenylmaleimide, N-nitrophenylmaleimide, N-methoxyphenylmaleimide, N-methylphenylmaleimide, N-carboxyphenylmaleimide, N-hydroxyphenylmaleimide, N-chlorophenylmaleimide, N-dimethylphenylmaleimide, N-dichlorophenylmaleimide, N-bromophenylmaleimide, N
-Dibromophenylmaleimide, N-trichlorophenylmaleimide, N-tribromophenylmaleimide and the like can be mentioned. Of these, N-phenylmaleimide is particularly preferably used. There is no limitation on the method for producing these maleimides, and those obtained by various methods can be used. Depending on the production method, the maleimides may contain an acid component, for example, the acid catalyst used in the reaction, and maleimides containing about 5% by weight of the acid component can also be used, but they may be washed with water and distilled. It is desirable that the content of the acid component is 0.3% by weight or less by the method described above.

The maleimides can be dissolved in acrylonitrile by any method, for example, by adding maleimides into acrylonitrile. Specifically, a method in which maleimides are filled in a substantially closed container having liquid circulation nozzles in the upper and lower portions and the acrylonitrile solution is circulated and dissolved while heating from the upper nozzle to the lower nozzle ( Japanese Patent Publication 6-70009
Japanese Patent Laid-Open No. 6-70008), in which a substantially sealed container equipped with one liquid circulation nozzle is filled with maleimides, and a heated acrylonitrile solution is repeatedly introduced and dissolved through this nozzle (Japanese Patent Publication No. 6-70008). Issue). The maleimides are preferably dissolved at a temperature not higher than the boiling point of acrylonitrile (78.5 ° C.), and usually a temperature in the range of 30 to 70 ° C. is preferred because acrylonitrile has a high vapor pressure. Also,
The temperature for handling the acrylonitrile solution is usually 30 to
70 ° C.

There are no particular restrictions on the material of the equipment that handles the acrylonitrile solution, and the surface of the equipment (including piping) that comes into contact with the acrylonitrile solution may be passivated, for example, glass lining, ceramic coating, etc. It is economical and advantageous to handle the acrylonitrile solution on an industrial scale by using equipment made of industrial materials such as carbon steel or stainless steel.

The concentration of the maleimides in the acrylonitrile solution is not particularly limited, and the handling temperature, the handling form (for example, transportation or storage), or the type of the copolymer produced using this acrylonitrile solution,
It can be appropriately determined in consideration of the production method and production conditions. For example, when it is used for producing an acrylonitrile-maleimide-containing copolymer having a high maleimide content, it may be preferable to use a high concentration. Usually, the concentration of maleimides is 40 to 90% by weight.

The acrylonitrile solution of the maleimides of the present invention is a clear solution. a. b. Value (that is, the L.
a. b. Values) are L = 90 to 100 and a = -10, respectively.
Acrylonitrile solutions in the range of -30 and b = 30-50 are preferably used.

Industrial acrylonitrile, which is generally used as a solvent, contains about 0.5 to 1% by weight of water. According to many years of research conducted by the present inventors, coloring or coloring of an acrylonitrile solution of maleimides or It has been found that the cloudiness is caused by the water in the acrylonitrile solution and thus the water contained in the acrylonitrile used as solvent. That is, for example, N-phenylmaleimide will be described as an example of the maleimides.
N-phenylmaleimide is hydrolyzed to produce N-phenylmaleamic acid that is insoluble in acrylonitrile, and this N-phenylmaleamic acid is further hydrolyzed to maleic acid and aniline. Is extremely corrosive, corrodes the surface of equipment that handles acrylonitrile solutions, especially equipment made of carbon steel or stainless steel, resulting in the formation of metal ions and, consequently, radical active species (hydroperoxide). It is believed that various aniline derivatives or low polymers are produced by this hydroperoxide, and the acrylonitrile solution is colored or clouded by these aniline and aniline derivatives or low polymers. The present invention is not limited by such theoretical consideration.

Thus, before and after the test according to the forced coloring test method of the present invention (hereinafter sometimes referred to simply as "before and after the test").
Difference ΔL, Δa and Δb are 5 or less, 5 or less and 10 or less, respectively, preferably 2 or less, 2 or less and 4 or less, more preferably 1 or less, 1 or less and 2 or less, particularly preferably respectively. 0.5 or less, 0.5
The following and 1 or less acrylonitrile solutions of maleimides can be efficiently prepared by the method described below, particularly when the acrylonitrile solution is handled using equipment made of carbon steel or stainless steel which is a general-purpose industrial material. <Method A> Method A comprises adjusting the amount of water in the acrylonitrile solution of maleimides to 0.1% by weight or less (see Example 9). If the water content exceeds 0.1% by weight, the acrylonitrile solution of the present invention cannot be prepared (see Comparative Examples 1 to 3). In order to reduce the amount of water in the acrylonitrile solution to 0.1% by weight or less, since the maleimides do not substantially contain water, the amount of water in the industrial acrylonitrile used as a solvent should be 0. 1
It may be less than or equal to weight%. The amount of water in acrylonitrile can be adjusted by a conventionally known method, for example, physical adsorption by precision distillation, silica gel, molecular sieve or the like, dehydration with anhydrous sodium sulfate, anhydrous magnesium sulfate, or the like. The smaller the amount of water in the acrylonitrile solution, the more preferable. The lower limit value can be appropriately determined in consideration of the clarity and stability of the acrylonitrile solution, economic cost, and the like.
In particular, the water content in the acrylonitrile solution is preferably 0.05% by weight or less, and by reducing the water content, the color differences ΔL, Δa and Δb before and after the test are 1 respectively.
Hereafter, 1 or less and 2 or less acrylonitrile solutions can be prepared.

<Method B> Method B comprises the coexistence of an antioxidant effective in preventing the generation of hydroperoxide as described above in the acrylonitrile solution. As the antioxidant, at least one selected from alkyl-substituted hydroxybenzenes and hindered phenols, or at least one selected from phosphite esters, phosphoric acid esters and phosphoric acid amides, is used alone. It can be used, but it is used in combination with at least one selected from alkyl-substituted hydroxybenzenes and hindered phenols and at least one selected from phosphites, phosphates and amides. It is effective to do. Thus, Method B can be performed in two forms:

<B-1> At least one selected from alkyl-substituted hydroxybenzenes and hindered phenols in an acrylonitrile solution of maleimides, and selected from phosphites, phosphates and amides. And at least one species are present (see Example 11). The amount of water in the acrylonitrile solution in this case is not limited, but in view of the amount of water in industrial acrylonitrile, the upper limit is usually 0.5 to 0.6% by weight.
It is about. The water content in the acrylonitrile solution is preferably as small as possible, and is preferably 0.3% by weight or less.

<B-2> The water content of the maleimides in the acrylonitrile solution is 0.3% by weight or less, and the acrylonitrile solution contains at least one selected from alkyl-substituted hydroxybenzenes and hindered phenols, or a At least one selected from phosphoric acid esters, phosphoric acid esters and phosphoric acid amides is present (see Example 12).

In the above methods B-1 and B-2, the water content in the acrylonitrile solution is set to 0.2% by weight or less, preferably 0.1% by weight or less, whereby the clarity and stability are further improved. Acrylonitrile solutions can be prepared. In particular, by setting the amount of water in the acrylonitrile solution to 0.05% by weight or less, it is possible to prepare an acrylonitrile solution in which the differences ΔL, Δa and Δb before and after the test are 1 or less, 1 or less and 2 or less, respectively. .

Typical examples of the alkyl-substituted hydroxybenzenes are 2,4-dimethyl-6-tert-butylphenol, 4-tert-butylcatechol,
2,5-di-tert-butylhydroquinone, 2-t
Examples thereof include ert-butyl hydroquinone and 4,4′-thio-bis (6-tert-butyl-m-cresol).

Typical examples of the hindered phenols are 2,4-bis (n-octylthio) -6- (4-
Hydroxy-3,5-di-tert-butylanilino)
-1,3,5-triazine, 2,2'-thiobis- (4
-Methyl-6-tert-butylphenol), triethyleneglycol-bis- (3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate), pentaerythritol-tetrakis (3-
(3,5-di-tert-butyl-4-hydroxyphenyl) propionate), octadecyl-3- (3,5
-Di-tert-butyl-4-hydroxyphenyl) propionate, 2,2-thio-diethylenebis (3-
(3,5-di-tert-butyl-4-hydroxyphenyl) propionate), 1,6-hexanediol-
Bis (3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate), Tris- (3,5
-Di-tert-butyl-4-hydroxybenzyl)-
Isocyanurate, 1,3,5-trimethyl-2,4
6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, N, N′-hexamethylenebis (3,5-di-tert-butyl-4-hydroxy-hydrocinnamide), 3 , 5-di-tert-butyl-4-hydroxy-benzylphosphonate-diethyl ester and the like.

Among these, 2,4-dimethyl-6
-Tert-butylphenol, 4-tert-butylcatechol, 2,5-di-tert-butylhydroquinone, 2-tert-dibutylhydroquinone, 4,
4'-thio-bis (6-tert-butyl-m-cresol), 2,4-bis (n-octylthio) -6- (4
-Hydroxy-3,5-di-tert-butylanilino) -1,3,5-triazine, 2,2'-thiobis-
(4-methyl-6-tert-butylphenol) and triethylene glycol-bis- (3- (3-ter
t-Butyl-5-methyl-4-hydroxyphenyl) propionate) is preferably used.

Typical examples of the phosphorous acid esters are triphenylphosphite, tris (nonylphenyl) phosphite, triethylphosphite, tris (2-ethylhexyl) phosphite, tridecylphosphite, tris (tridecyl) phosphite. Fight, tristearyl phosphite, diphenyl mono (2-ethylhexyl) phosphite, diphenyl monodecyl phosphite, diphenyl monotridecyl phosphite, dilauryl hydrogen phosphite, dilauryl hydrogen phosphite, diphenyl hydrogen phosphite,
Tetraphenyl dipropylene glycol phosphite,
Tetraphenyltetra (tridecyl) pentaerythritol tetraphosphite, tetra (tridecyl) -4,
4'-isopropylidene diphenyl phosphite, trilauryl trithiophosphite, bis (tridecyl) pentaerythritol diphosphite, bis (nonylphenyl) pentaerythritol phosphite, distearyl pentaerythritol diphosphite, tris (2,
4-di-tert-butylphenyl) phosphite, hydrogenated bisphenol A-pentaerythritol phosphite polymer, hydrogenated bisphenol A-phosphite polymer and the like.

Typical examples of phosphoric acid esters and phosphoric acid amides include ethyldiethylphosphonoacetate,
Ethyl acid phosphate, β-chloroethyl acid phosphate, butyl acid phosphate, butylpyrophosphate, butoxyethyl acid phosphate, 2-ethylhexyl acid phosphate, di (2
-Ethylhexyl) phosphate, ethylene glycol acid phosphate, (2-hydroxyethyl) methacrylate acid phosphate, tris (2-chloroethyl) phosphate, tris (dichloropropyl) phosphate, octyldichloropropyl phosphate,
Examples thereof include phenyldichloropropyl phosphate, trimethyl phosphate, triethyl phosphate, tributyl phosphate, trioctyl phosphate, tricresyl phosphate, triphenyl phosphate, hexamethylphosphoric triamide and the like.

Among these phosphorous acid esters, phosphoric acid esters and phosphoric acid amides, tris (nonylphenyl) phosphate, distearyl pentaerythritol diphosphite, tristearyl phosphite,
Di (2-ethylhexyl) phosphate is preferably used.

At least one selected from the above alkyl-substituted hydroxybenzenes and hindered phenols
The amount of seed used is 0.0001 to 1% by weight, preferably 0.001 to 0.1% by weight, based on the maleimide. The amount of at least one selected from the above phosphites, phosphates and amides is 0.0001 to 1% by weight, preferably 0.001 to 0.1% by weight, based on maleimides. %. When at least one selected from alkyl-substituted hydroxybenzenes and hindered phenols and at least one selected from phosphite esters, phosphoric acid esters and phosphoric acid amides are used in combination, the ratio is particularly There is no limitation, and the amount can be appropriately determined within the above range of use.

In the case of the above combination, a particularly preferable combination is 4-tert-butylcatechol and distearylpentaerythritol diphosphite, and triethyleneglycol-bis [3- (3-ter).
t-Butyl-5-methyl-4-hydroxyphenyl) propionate] with distearyl pentaerythritol diphosphite, and 4-tert-butyl catechol with tristearyl phosphite.

In the above methods A and B, the metal deactivation is carried out by defining the molecular oxygen concentration in the gas phase part of the acrylonitrile solution of maleimides in a specific range or in order to prevent the generation of the hydroperoxide. By adding the agent, it is possible to prepare an acrylonitrile solution of maleimides having further excellent clarity and stability. These methods will be described below.

<Method C> In Method C, the molecular oxygen concentration in the gas phase part of the acrylonitrile solution of maleimides (volume basis of gas mixture excluding maleimides and acrylonitrile; the same applies hereinafter) is 0 in the above methods A and B. ．
It consists of adjusting to 01-10% by volume. When the molecular oxygen concentration exceeds 10% by volume, coloration and cloudiness cannot be prevented more effectively, while when the molecular oxygen concentration is less than 0.01% by volume, maleimides and monomers other than acrylonitrile are mixed, or storage tanks, etc. There is a case where a problem such as clouding of the acrylonitrile solution due to contamination of the container is caused, which is not preferable. Thus, the molecular oxygen concentration is 0.01 to 10% by volume, preferably 0.1 to 8% by volume,
More preferably, it is 1 to 7% by volume. The gas mixture excluding the maleimides and acrylonitrile is
Usually molecular oxygen and nitrogen, carbon dioxide, helium,
It is composed of an inert gas such as argon, and nitrogen is particularly preferably used as the inert gas. Therefore, a preferable example of the gas mixture excluding maleimides and acrylonitrile is a gas mixture composed of molecular oxygen and nitrogen. Can be mentioned. Specifically, it is as follows.

<C-1> The amount of water in the acrylonitrile solution of maleimides is set to 0.1% by weight or less, and the molecular oxygen concentration in the gas phase part of the acrylonitrile solution is 0.01 to 0.01%.
Adjust to 10% by volume (see Example 13).

<C-2> At least one selected from alkyl-substituted hydroxybenzenes and hindered phenols in an acrylonitrile solution of maleimides, and selected from phosphites, phosphates and amides. And at least one, and the molecular oxygen concentration in the gas phase part of the acrylonitrile solution is 0.0
Adjust to 1-10% by volume (see Examples 1, 2, 3, 6).

<C-3> The amount of water in the acrylonitrile solution of maleimides is 0.3% by weight or less, and at least one selected from alkyl-substituted hydroxybenzenes and hindered phenols in the acrylonitrile solution, or a sub-component. At least one selected from phosphoric acid esters, phosphoric acid esters and phosphoric acid amides is present, and the molecular oxygen concentration in the gas phase of the acrylonitrile solution is adjusted to 0.01 to 10% by volume (Examples) 10
reference).

In the above methods C-1 to C-3, by setting the water content in the acrylonitrile solution to 0.2% by weight or less, preferably 0.1% by weight or less, the clarity and stability are further improved. Acrylonitrile solutions can be prepared. In particular, by setting the amount of water in the acrylonitrile solution to 0.05% by weight or less, it is possible to prepare an acrylonitrile solution in which the differences ΔL, Δa and Δb before and after the test are 1 or less, 1 or less and 2 or less, respectively. .

<Method D> The method D comprises adding the metal deactivator to the acrylonitrile solution in the methods A to C. A typical example of the metal deactivator is N, N′-bis [3- (3,5-di-te].
rt-Butyl-4-hydroxyphenyl) propionyl] hydrazine, 2,2′-oxamide bis- [ethyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], N, N′-disalicylidene Examples include -1,2-propanediamine, benzotriazole, tolyltriazole, tolyltriazole-potassium salt, and mercaptobenzotriazole-sodium salt. Of these, N, N'-bis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyl] hydrazine, 2,2'-
Oxamide bis- [ethyl-3- (3,5-di-ter
t-butyl-4-hydroxyphenyl) propionate] and the like are preferably used. These metal deactivators may be used alone or in admixture of two or more. The amount of the metal deactivator added is 0.0001 to 1% by weight, preferably 0.001 to 1% by weight, based on the maleimides.
0.1% by weight. Specifically, it is as follows.

<D-1> The amount of water in the acrylonitrile solution of maleimides is set to 0.1% by weight or less, and a metal deactivator is added (see Example 14).

<D-2> The amount of water in the acrylonitrile solution of maleimides is set to 0.1% by weight or less, and the molecular oxygen concentration in the gas phase part of the acrylonitrile solution is 0.01 to 0.01%.
Adjust to 10% by volume and add metal deactivator (see Example 15).

<D-3> At least one selected from alkyl-substituted hydroxybenzenes and hindered phenols in an acrylonitrile solution of maleimides, and selected from phosphites, phosphates and amides. And at least one metal deactivator are added (see Example 4).

<D-4> The amount of water in the acrylonitrile solution of maleimides is set to 0.3% by weight or less, and at least one selected from alkyl-substituted hydroxybenzenes and hindered phenols in the acrylonitrile solution, or a sub-method. At least one selected from phosphoric acid esters, phosphoric acid esters and phosphoric acid amides is present, and a metal deactivator is added (see Example 16).

<D-5> At least one selected from alkyl-substituted hydroxybenzenes and hindered phenols in an acrylonitrile solution of maleimides, and selected from phosphites, phosphates and amides. And at least one of them is present, and the molecular oxygen concentration in the gas phase part of the acrylonitrile solution is 0.0
It is adjusted to 1 to 10% by volume, and a metal deactivator is added (see Examples 5, 7, and 8). <D-6> The amount of water in the acrylonitrile solution of maleimides is 0.3 wt% or less, and at least one selected from alkyl-substituted hydroxybenzenes and hindered phenols in the acrylonitrile solution, or phosphite ester , At least one selected from phosphoric acid esters and phosphoric acid amides is present, and the molecular oxygen concentration in the gas phase part of the acrylonitrile solution is 0.01 to
Adjust to 10% by volume and add metal deactivator (see Example 17).

In the above methods D-1 to D-6, the water content in the acrylonitrile solution is 0.2% by weight or less, preferably less than 0.1% by weight, whereby the clarity and stability are further improved. Acrylonitrile solutions can be prepared. In particular, by setting the amount of water in the acrylonitrile solution to 0.05% by weight or less, it is possible to prepare an acrylonitrile solution in which the differences ΔL, Δa and Δb before and after the test are 1 or less, 1 or less and 2 or less, respectively. .

Differences before and after the test of the present invention ΔL, Δa and Δ
The acrylonitrile solution of maleimides in which b is 5 or less, 5 or less and 10 or less, preferably 1 or less, 1 or less and 2 or less, respectively, is clear and has excellent stability without coloring or clouding. By using this acrylonitrile solution of maleimides, an acrylonitrile-maleimide-containing copolymer excellent in color tone can be obtained. That is, acrylonitrile-butadiene-styrene (AB containing maleimides, respectively)
S) resin, acrylonitrile-acrylic rubber-styrene (AAS) resin, acrylonitrile-styrene (AS)
It is possible to obtain an acrylonitrile-maleimide-containing copolymer having excellent clarity and heat resistance, such as a resin or an acrylonitrile-chlorinated polyethylene-styrene (ACS) resin.

These acrylonitrile-maleimide-containing copolymers can be easily produced by a conventionally known method. That is, it can be produced by using the acrylonitrile solution of maleimides of the present invention instead of the conventional acrylonitrile solution of maleimides. It should be noted that these acrylonitrile-maleimide-containing copolymers can be blended with various conventionally known additives, if necessary.

[0054]

EXAMPLES The present invention will be described more specifically below with reference to examples and comparative examples. The N-phenylmaleimide used was prepared by the following synthesis example.

Synthetic Example N-phenylmaleamic acid obtained from aniline and maleic anhydride was reacted in the presence of an acid catalyst in an o-xylene solvent at a temperature of 130 ° C. or higher. The water produced is o-
The reaction was allowed to proceed while distilling it out of the system as a mixture with xylene. The reaction mixture obtained by ring-closing imidation was separated into an organic solvent layer containing N-phenylmaleimide and a catalyst layer, and the organic solvent layer was washed with water. O-xylene was removed from the organic solvent layer thus obtained under reduced pressure, and then distilled to obtain yellow N-phenylmaleimide. As a result of analysis by liquid chromatography, this product had a purity of 99.5% or more.

Example 1 Two 18 mm (inner diameter) × 180 mm (height) Pyrex test tubes were prepared. In each test tube, 9 g of N-phenylmaleimide and 6 g of acrylonitrile having a water content of 0.005% by weight were put and dissolved, and then pentaerythrityl-tetrakis [3- (3,5-di-tert-butyl-4-hydroxy) was added. Phenyl) propionate] (antioxidant (a-1)) 4.5 mg and tristearyl phosphite (antioxidant (b-1)) 4.5 mg are added, and the water content is further adjusted to obtain N-phenyl. Maleimide concentration 60% by weight, water content 0.1% by weight, antioxidant (a-1) content of 500 ppm (vs. N-phenylmaleimide; the same applies hereinafter) and antioxidant (b-1) content of 500
A ppm acrylonitrile solution was prepared.

One test tube of acrylonitrile solution L. a. b. The value was measured after its preparation, L = 9
The values were 9.3, a = -21.0, and b = 39.0. For the other test tubes, the gas phase part of the acrylonitrile solution was replaced with nitrogen gas containing 7% by volume of molecular oxygen, and then subjected to the forced coloring test of the present invention. 3 days (72 hours)
After that, the test piece was taken out, and L. a. a. b. When the value was measured, L = 98.6, a
= -19.8, b = 41.2, and the color differences before and after the test were ΔL = 0.7, Δa = 1.2, and Δb = 2.2.
The solution after the test was clear. The results are shown in Table 1.

Example 2 As an antioxidant, triethylene glycol-bis [3
-(3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate] (antioxidant (a-
2)) and trisnonylphenyl phosphite (antioxidant (b-2)) according to the method of Example 1,
The acrylonitrile solutions shown in Table 1 were prepared. Less than,
In the same manner as in Example 1, the L. a. b. The value and the color difference before and after the test were measured. The results are shown in Table 1.

Example 3 As an antioxidant, octadecyl-3- (3,5-di-
tert-Butyl-4-hydroxyphenyl) propionate (antioxidant (a-3)) and distearyl pentaerythritol diphosphite (antioxidant (b-
3)) was used according to the method of Example 1 to prepare an acrylonitrile solution shown in Table 1. Thereafter, in the same manner as in Example 1, the L. a. b. The value and the color difference before and after the test were measured. The results are shown in Table 1. Example 4 4-tert-butylcatechol (antioxidant (a-4)) and distearyl pentaerythritol diphosphite (antioxidant (b-
3)), and N, N'-bis [3] as a metal deactivator.
-(3,5-di-tert-butyl-4-hydroxyphenyl) propionyl] hydrazine (inactivating agent (c-
1)) was used according to the method of Example 1 to prepare an acrylonitrile solution shown in Table 1. Thereafter, in the same manner as in Example 1, the L. a. b. The value and the color difference before and after the test were measured. The results are shown in Table 1.

Example 5 As an antioxidant, triethylene glycol-bis [3
-(3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate] (antioxidant (a-
2)) and distearyl pentaerythritol diphosphite (antioxidant (b-3)), and 2,2'-oxamide bis- [ethyl-
3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] (inactivating agent (c-2))
Was used according to the method of Example 1 to prepare an acrylonitrile solution shown in Table 1. Thereafter, in the same manner as in Example 1, the L. a. b. The value and the color difference before and after the test were measured. The results are shown in Table 1.

[0061]

[Table 1]

Example 6 As the antioxidant, 4-tert-butylcatechol (antioxidant (a-4)) and di (2-ethylhexyl) phosphate (antioxidant (b-4)) were used. According to the method of 1, the acrylonitrile solution shown in Table 2 was prepared. Thereafter, in the same manner as in Example 1, the L. a. b. The value and the color difference before and after the test were measured. The results are shown in Table 2.

Example 7 As an antioxidant, triethylene glycol-bis [3
-(3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate] (antioxidant (a-
2)) and distearyl pentaerythritol diphosphite (antioxidant (b-3)), and 2,2'-oxamide bis- [ethyl-3- as a metal deactivator.
(3,5-di-tert-butyl-4-hydroxyphenyl) propionate] (inactivating agent (c-2)) was used to prepare an acrylonitrile solution shown in Table 2 according to the method of Example 1. did. Hereinafter, in the same manner as in Example 1,
L. a. Of this acrylonitrile solution. a. b. The value and the color difference before and after the test were measured. The results are shown in Table 2.

Example 8 As an antioxidant, triethylene glycol-bis [3
-(3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate] (antioxidant (a-
2)) and distearyl pentaerythritol diphosphite (antioxidant (b-3)), and 2,2'-oxamide bis- [ethyl-3- as a metal deactivator.
Using (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] (inactivating agent (c-2)), the acrylonitrile solution shown in Table 2 was prepared according to the method of Example 1. . Hereinafter, in the same manner as in Example 1,
L. a. Of this acrylonitrile solution. a. b. The value and the color difference before and after the test were measured. The results are shown in Table 2.

Example 9 According to the method of Example 1, an acrylonitrile solution shown in Table 2 was prepared. Thereafter, in the same manner as in Example 1, the L. a. b. The value and the color difference before and after the test were measured. The results are shown in Table 2.

Example 10 As an antioxidant, 1,6-hexanediol-bis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] (antioxidant (a-
5)) was used according to the method of Example 1 to prepare an acrylonitrile solution shown in Table 2. Thereafter, in the same manner as in Example 1, the L. a. b. The value and the color difference before and after the test were measured. The results are shown in Table 2.

[0067]

[Table 2]

Example 11 As an antioxidant, triethylene glycol-bis [3
-(3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate] (antioxidant (a-
2)) and distearyl pentaerythritol diphosphite (antioxidant (b-3)) were used and the acrylonitrile solution shown in Table 3 was prepared according to the method of Example 1. Thereafter, in the same manner as in Example 1, the L. a. b. The value and the color difference before and after the test were measured. The results are shown in Table 3.

Example 12 Using distearyl pentaerythritol diphosphite (antioxidant (b-3)) as an antioxidant, an acrylonitrile solution shown in Table 3 was prepared according to the method of Example 1. . Thereafter, in the same manner as in Example 1, the L. a. b. The value and the color difference before and after the test were measured. The results are shown in Table 3.

Example 13 According to the method of Example 1, an acrylonitrile solution shown in Table 3 was prepared. Thereafter, in the same manner as in Example 1, the L. a. b. The value and the color difference before and after the test were measured. The results are shown in Table 3.

Example 14 As a metal deactivator, 2,2'-oxamide bis- [ethyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] (deactivator (c-
2)) was used and the acrylonitrile solution shown in Table 3 was prepared according to the method of Example 1. Thereafter, in the same manner as in Example 1, the L. a. b. The value and the color difference before and after the test were measured. The results are shown in Table 3.

Example 15 2,2'-Oxamide bis- [ethyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] as a metal deactivator (deactivator (c-
2)) was used and the acrylonitrile solution shown in Table 3 was prepared according to the method of Example 1. Thereafter, in the same manner as in Example 1, the L. a. b. The value and the color difference before and after the test were measured. The results are shown in Table 3.

[0073]

[Table 3]

Example 16 Di (2-ethylhexyl) phosphate (antioxidant (b-4)) was used as an antioxidant, and N, N'-bis [3- (3,5-) was used as a metal deactivator. The acrylonitrile solution shown in Table 4 was prepared according to the method of Example 1 using di-tert-butyl-4-hydroxyphenyl) propionyl] hydrazine (inactivating agent (c-1)). Thereafter, in the same manner as in Example 1, the L. a. b. The value and the color difference before and after the test were measured. The results are shown in Table 4.

Example 17 As an antioxidant, distearyl pentaerythritol diphosphite (antioxidant (b-3)), and as a metal deactivator, 2,2'-oxamide bis- [ethyl-3- ( 3,5-di-tert-butyl-4-hydroxyphenyl) propionate] (inactivating agent (c-
2)) was used and the acrylonitrile solution shown in Table 4 was prepared according to the method of Example 1. Thereafter, in the same manner as in Example 1, the L. a. b. The value and the color difference before and after the test were measured. The results are shown in Table 4.

[0076]

[Table 4]

Comparative Examples 1 to 3 Acrylonitrile solutions shown in Table 5 were prepared and Example 1
In the same manner as in L. a. b. The value and the color difference before and after the test were measured. The results are shown in Table 5.

[0078]

[Table 5]

Example 18 38.4 g of styrene was placed in a 1-liter four-necked flask equipped with a stirrer, a condenser, a nitrogen gas introducing tube and a dropping funnel.
And toluene 269.3 g (both Wako Pure Chemical Industries, Ltd.)
(Manufactured by: reagent special grade) was charged, the gas phase was sufficiently replaced with nitrogen, and then heated to 90 ° C. 172.7 g of an acrylonitrile solution of N-phenylmaleimide obtained in Example 4 was added thereto.
And toluene 54.3 g mixed solution, styrene 102.
4 g, and a solution of 0.26 g of benzoyl peroxide (manufactured by NOF CORPORATION) and 12.2 g of toluene were added dropwise with a dropping funnel over 3 hours while maintaining the internal temperature at 90 ° C. After the dropping was completed, stirring was continued for another 1.5 hours.

Next, a part of the reaction product was taken out, diluted with methyl ethyl ketone, and then reprecipitated in methanol by a conventional method. After the precipitated polymer was filtered and dried, a melt indexer (L240 manufactured by Techno Seven Co., Ltd.) was used.
It was put into a mold and heated at 240 ° C. for 4 hours, and then formed into a strand. Visual observation of the polymer thus formed into a strand revealed that the appearance was pale yellow and clear.

Comparative Example 4 A strand polymer was obtained in the same manner as in Example 9 except that the N-phenylmaleimide acrylonitrile solution obtained in Comparative Example 1 was used. The appearance of this polymer was yellowish brown and was clearly colored.

Example 18 L, a, b, values and color differences before and after the test were carried out in the same manner as in Example 4 except that the molecular oxygen concentration in the gas phase part of the acrylonitrile solution was changed to 5% by volume. Was measured. The results are shown in Table 6.

Example 19 L, a, b, values and color differences before and after the test were carried out in the same manner as in Example 9 except that the molecular oxygen concentration in the gas phase part of the acrylonitrile solution was changed to 5% by volume. Was measured. The results are shown in Table 6.

Example 20 Example 11 was repeated except that the concentration of molecular oxygen in the gas phase of the acrylonitrile solution was changed to 5% by volume.
The L, a, b, and the color difference before and after the test were measured in the same manner as in. The results are shown in Table 6.

Example 21 Example 12 was repeated except that the concentration of molecular oxygen in the gas phase part of the acrylonitrile solution was changed to 5% by volume.
The L, a, b, and the color difference before and after the test were measured in the same manner as in. The results are shown in Table 6.

Example 22 Example 14 was repeated except that the concentration of molecular oxygen in the gas phase of the acrylonitrile solution was changed to 5% by volume.
The L, a, b, and the color difference before and after the test were measured in the same manner as in. The results are shown in Table 6.

[0087]

[Table 6]

Example 23 Example 16 was repeated except that the concentration of molecular oxygen in the gas phase of the acrylonitrile solution was changed to 5% by volume.
The L, a, b, and the color difference before and after the test were measured in the same manner as in. The results are shown in Table 7.

Comparative Example 5 L, a, b, values and color differences before and after the test were carried out in the same manner as in Comparative Example 1 except that the molecular oxygen concentration in the gas phase part of the acrylonitrile solution was changed to 7% by volume. Was measured. The results are shown in Table 7.

[0090]

[Table 7]

[0091]

The maleimide acrylonitrile solution of the present invention is clear and has excellent stability without coloration or clouding during its handling.

According to the method of the present invention, an acrylonitrile solution of the above maleimides can be efficiently prepared.

By using the acrylonitrile solution of maleimides having excellent clarity as described above, an acrylonitrile-maleimide-containing copolymer having excellent color tone can be obtained.

Claims (6)

[Claims] 1. A color difference Δ before and after the test according to the forced coloring test method.
L, Δa and Δb are 5 or less, 5 or less and 1 respectively
An acrylonitrile solution of maleimides, which is 0 or less. Where ΔL = | L value after test−L value before test | (absolute value) Δa = | a value after test−a value before test | (absolute value) Δb = | b after test Value-b value before test | (absolute value) 2. The method for preparing an acrylonitrile solution according to claim 1, wherein the water content of the maleimide acrylonitrile solution is 0.1% by weight or less. 3. A solution of maleimides in an acrylonitrile, and at least one selected from alkyl-substituted hydroxybenzenes and hindered phenols and at least one selected from phosphites, phosphates and amides. The method for preparing an acrylonitrile solution according to claim 1, characterized in that 4. A water content of maleimides in an acrylonitrile solution is set to 0.3% by weight or less, and at least one selected from alkyl-substituted hydroxybenzenes and hindered phenols in the acrylonitrile solution,
Alternatively, the method for preparing an acrylonitrile solution according to claim 1, wherein at least one selected from phosphite esters, phosphoric acid esters and phosphoric acid amides is present. 5. An acrylonitrile-maleimide-containing copolymer obtained by using the acrylonitrile solution of the maleimide according to claim 1. 6. When the acrylonitrile solution according to claim 1 is stored in contact with a metal, the concentration of molecular oxygen in the vapor phase part of the solution is adjusted to 0.01 to 10% by volume. Method for storing acrylonitrile solution of maleimides.