JPH08143607A - Production of thermoplastic ion-crosslinked polymer product - Google Patents

Abstract

PURPOSE: To obtain an ion-crosslinked polymer product with high degree of crosslinking without any intricate step, safe in sanitation, easy to reutilize its raw materials, by polymerizing styrene in the presence of a zinc salt mixture formed through reaction between (meth)acrylic acid, stearic acid and zinc oxide. CONSTITUTION: This invention comprises a bulk polymerization between (A) an aromatic vinyl-based monomer and (B) a zinc salt mixture containing (meth) acrylic acid and a 5-40C carboxyl group-containing compound as acid components in a reaction system substantially containing no dimethylformamide. Namely, the copolymerization reaction is conducted in a system containing no organic solvent capable of dissolving zinc di(meth)acrylate and compatibilizing it with the aromatic vinyl-based monomer. The bulk copolymerization is conducted in a continuous bulk polymerization line having a tubular reactor in which plural mixing elements without any movable part are fixed, while making a static agitation. The mixture is used at 0.01-5mol% in terms of zinc content based on the molar number of the monomer. The mixture is obtained by reaction between a zinc compound such as zinc oxide, etc., and acid components containing 25-99mol% of (meth)acrylic acid.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a thermoplastic ionic crosslinked product, which is an injection-molded product in the fields of weak electricity, electronics, toys, sundries, and sheets and films for packaging materials. The present invention provides an aromatic vinyl-based resin cross-linked with a zinc salt, which can be widely used for extruded products and the like.

[0002]

2. Description of the Related Art Conventionally, aromatic vinyl resins represented by polystyrene are resins excellent in moldability, rigidity, and electrical characteristics, so that they are used in household products, audio / visual fields, weak electrical fields, and uniaxial stretching. And biaxially oriented sheet,
It has been used in various fields such as sheet-shaped processed products such as films, film-shaped processed products, and foam-processed products such as foamed sheets. Among them, in the field where high strength is required, it has been dealt with by increasing the molecular weight of the aromatic vinyl resin. However, the method of improving the strength by increasing the molecular weight of the polymer has a problem that the fluidity is deteriorated and the moldability is deteriorated.

In order to solve such a problem, for example, in JP-A-4-258612, in a mixed solution of acrylic acid and dimethylformamide in an equimolar amount or more to acrylic acid, 0 is added to acrylic acid. A transparent homogeneous solution prepared by adding and reacting 5 times or less mole of zinc oxide with an aromatic vinyl compound unit or this and one or more other vinyl compound units are mixed, and further radical-polymerized as a transparent homogeneous solution to produce ions. A method of forming a crosslinked polymer is disclosed. That is, the ionically crosslinked polymer described in the publication reduces the intermolecular crosslinkability when the resin is in a fluidized state at high temperature by introducing a metal ion crosslinking site into the aromatic vinyl resin. This enables free thermoplastic processing.

[0004]

However, in the method disclosed in Japanese Patent Laid-Open No. 4-258612, dimethylformamide, which is known to stimulate the mucous membrane strongly and is also absorbed by the skin and causes poisoning, is used. There is a safety and health problem that we must do, and
After synthesizing zinc diacrylate in the presence of dimethylformamide and then dissolving it in an aromatic vinyl compound, a large amount of dimethylformamide had to be added, which was complicated in the process.

Further, since the obtained zinc diacrylate is not sufficiently soluble in styrene, the degree of crosslinking of the aromatic vinyl resin is low and the strength is not satisfactory. Furthermore, in order to reuse the raw material styrene from the recovered components in the devolatilization step after resin synthesis, it is necessary to separate and purify the recovered dimethylformamide from the monomer, solvent and the like, and a distillation facility and the like were required. .

The problem to be solved by the present invention is to eliminate such safety and health problems and complexity of the process, and the degree of crosslinking of the resulting thermoplastic ionic crosslinked product is high. Another object of the present invention is to provide a method for producing a thermoplastic ionic crosslinked product, which can be easily reused.

[0007]

Means for Solving the Problems As a result of intensive studies, the inventors of the present invention constituted an ionic crosslinked structure site (meta).
As a zinc acrylate salt, by using a specific carboxyl group-containing compound together with (meth) acrylic acid, the solubility in an aromatic vinyl monomer is improved, and it was found that the above problems can be solved and the present invention is completed. Came to.

That is, the present invention relates to a mixture of a vinyl salt (A), a zinc salt containing (meth) acrylic acid and a carboxyl group-containing compound having 5 to 40 carbon atoms as an acid component (B). ) And are bulk polymerized in a system substantially free of dimethylformamide, and a method for producing a thermoplastic ionic crosslinked product.

The term "substantially dimethylformamide-free system" as used herein means a system that does not use dimethylformamide at all, or the amount of dimethylformamide present is limited to an amount that does not complicate the safety and hygiene or the process. Aromatic vinyl monomer (A) 10
It is preferably 1 part by weight or less, more preferably 0.3 part by weight or less, and further preferably 0.1 part by weight or less, relative to 0 part by weight.

Further, the present invention is an organic solvent capable of dissolving not only the above-mentioned dimethylformaldehyde but also a zinc salt of di (meth) acrylic acid as the organic solvent substantially removed from the reaction system, and When the zinc salt solution is dissolved in the aromatic vinyl-based monomer (A), an organic solvent that can be compatibilized with the aromatic vinyl-based monomer (A) in an amount of 20% by weight or less of the organic solvent content is also used. Preferred examples include: That is, when the aromatic vinyl-based monomer (A) and the zinc di (meth) acrylic acid salt are compatibilized with such an organic solvent, the solubility is not sufficiently enhanced, and as a result, The resulting ionic crosslinked product has a low degree of crosslinking and is inferior in strength. Further, if the organic solvent is highly toxic, it is possible to avoid safety and health problems.
The above-mentioned dimethylformamide can be mentioned as an example of the organic solvent.

The zinc salt mixture (B) used in the present invention is
(Meth) acrylic acid and a carboxyl group-containing compound having 5 to 40 carbon atoms as an acid component, which is a mixture of zinc salt and a zinc salt, for example, (meth) acrylic acid and 5 to 40 carbon atoms. Examples thereof include those obtained by reacting with a zinc compound in the coexistence of a carboxyl group-containing compound. More specifically, zinc di (meth) acrylate, a zinc salt of a carboxyl group-containing compound having 5 to 40 carbon atoms, (meth) acrylic acid and a zinc salt of a carboxyl group containing compound having 5 to 40 carbon atoms The thing containing 3 components as a main component is mentioned.

The carboxyl group-containing compound having 5 to 40 carbon atoms is not particularly limited, but typically includes valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, and undecyl. Acid, dodecyl acid, octylic acid, lauric acid, myristic acid, palmitic acid, stearic acid, isostearic acid, nondecanoic acid, arachidic acid, behenic acid, lignosalinic acid, cerotic acid, heptacosanoic acid, montanic acid, melicinic acid, laxeric acid, Unsaturation of saturated fatty acids such as cyclohexanecarboxylic acid and mixtures thereof, undecylenic acid, oleic acid, elaidic acid, cetrainic acid, sorbic acid, linoleic acid, linolenic acid, arachidonic acid, propiolic acid, stearolic acid, beef tallow fatty acid, etc. Fatty acid, naphthenic acid, benzoic acid, methoxyphen Acetic acid, oxynaphthoic acid, salicylic acid, diphenyl-4-carboxylic acid, diphenylacetic acid, terephthalic acid, toluic acid, naphthoic acid, hydroxyphenylacetic acid, phenylacetic acid, phenoxyacetic acid, benzylic acid, benzoylbenzoic acid, mandelic acid, t -Carboxylic acid compounds containing a benzene skeleton such as butyl benzoic acid, a plurality of carboxylic acid-containing compounds such as adipic acid, sebacic acid, dodecanedioic acid, ε-caprolactone, δ-valerolactone obtained by ring-opening polymerization Examples thereof include carboxylic acid-containing compounds having an ester bond, nitrogen-containing carboxylic acid-containing compounds such as aminododecanoic acid, and the like.

Of these, aliphatic carboxylic acids are preferred because of their excellent solubility in aromatic vinyl monomers, and unsaturated aliphatic carboxylic acids are particularly preferred because of their high solubility at room temperature.

The carboxyl group-containing compound has 5 to 40 carbon atoms, but when the number of carbon atoms is less than 5 or the number of carbon atoms exceeds 40, the solubility in the aromatic vinyl monomer is high. Is poor, and only an ionic crosslinked product having a low degree of crosslinking can be obtained.

Among them, the number of carbon atoms is preferably 6 to 22, and particularly preferably 14 to 22 from the viewpoint of excellent solubility in an aromatic vinyl monomer, and specifically, the number of carbon atoms. An aliphatic carboxylic acid having 6 to 22,
Particularly, an aliphatic carboxylic acid having 14 to 22 carbon atoms is preferable, and an unsaturated aliphatic carboxylic acid having 14 to 22 carbon atoms is more preferable.

The content of (meth) acrylic acid in the acid component constituting the zinc salt mixture (B) is not particularly limited, but is 25 from the viewpoint of solubility and crosslinkability.
It is preferably ˜99 mol%.

The method for producing the mixture (B) of zinc salts is not particularly limited, but for example, (meth) acrylic acid is reacted with the above-mentioned compound containing a carboxyl group having 5 to 40 carbon atoms. There is a method in which the mixture is charged in a container, further dissolved by adding an organic solvent, and then heated to 10 to 60 ° C., and then the zinc compound is continuously or intermittently added with stirring and mixing.

The ratio of (meth) acrylic acid to the carboxyl group-containing compound having 5 to 40 carbon atoms used in the above-mentioned production method is not particularly limited, but the acid is used in view of solubility and crosslinking. It is preferable to use the (meth) acrylic acid in the component at a ratio of 25 to 99 mol%. That is, when it is less than 25 mol%, the content of (meth) acrylic acid is low and the effect of crosslinking is weakened, and when it exceeds 99 mol%, the solubility in an aromatic vinyl compound is weakened.

As the zinc compound used here,
Examples include, but are not limited to, zinc oxide, zinc hydroxide, and mixtures thereof. Among these, zinc oxide is preferable because it has excellent reactivity with the acid component. The amount of the zinc compound used is not particularly limited, but is 50 mol% with respect to the acid component.
The following is preferable from the viewpoint that the amount of unreacted zinc compound remaining decreases.

Examples of the organic solvent used here include aromatic solvents such as styrene, benzene, toluene, xylene and ethylbenzene, and alcohol solvents such as methyl alcohol, ethyl alcohol, propyl alcohol and butyl alcohol. Of these, styrene, toluene, and methyl alcohol are preferable because they are excellent in reactivity between the acid component and the zinc compound. Particularly, after the zinc salt mixture (B) is formed, an aromatic vinyl monomer is obtained without removing the organic solvent. Styrene is particularly preferable because it can be used for the radical polymerization.

The mixture (B) of zinc salts described in detail above is prepared by reacting (meth) acrylic acid with zinc oxide in a solvent of dimethylformamide, and then drying the solvent by vacuum drying or the like.
Compared with zinc (meth) acrylate obtained by removing it, it shows extremely excellent solubility in aromatic vinyl monomers.

Specifically, the solubility of zinc acrylate using dimethylformamide as a reaction solvent and styrene at 90 ° C. is 0.1% by weight or less, while stearic acid and (meth) acrylic acid are equivalent. In the case of a zinc salt mixture of (meth) acrylic acid and stearic acid obtained by reacting a molar amount of the mixture with zinc oxide, 9
Solubility in styrene at 0 ° C is 10% by weight or more, which is 2 even when converted to the amount of (meth) acrylic acid unit.
The solubility is drastically improved when the content is at least wt%.

Further, a dimethylamide solution of zinc acrylate prepared by the method described in JP-A-4-25861 described above is mixed with styrene so that the amount of zinc acrylate is 1% by weight in terms of zinc acrylate. As a result, white turbidity occurred and the solubility of the zinc salt in styrene was insufficient.
The solubility of the mixture (B) having a mixing molar ratio of 1 to styrene was 15% by weight or more, and was 3% by weight or more when calculated as the amount of zinc acrylate salt. That is, the method according to the present invention not only eliminates the use of dimethylformamide, which is unfavorable for safety and hygiene, but also significantly improves the solubility of zinc acrylate in styrene.

Further, in the specification of JP-A-4-258612, even if powdered zinc acrylate is mixed with vinyl monomer such as styrene as a method without using dimethylformamide, a uniform solution is not obtained. Describes that zinc acrylate is hardly contained in the polymer, but as compared with such powdery zinc acrylate, the solubility in aromatic vinyl monomers is extremely excellent as described above. Becomes

Next, examples of the aromatic vinyl monomer (A) used in the present invention include styrene, alpha methyl styrene, alkylated alpha methyl styrene, ethyl styrene, isobutyl styrene, tertiary butyl styrene, brom styrene, Examples thereof include styrene-based monomers such as chlorostyrene and vinyltoluene, and mixtures thereof. Among them, styrene is preferable from the viewpoint of moldability.

In the present invention, in addition to the aromatic vinyl monomer (A), a polymerizable monomer copolymerizable with the aromatic vinyl monomer (A) may be used in combination. it can. Examples of such a polymerizable monomer include (meth)
Acrylic acid; (meth) acrylic acid alkyl esters such as methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, and iso-butyl (meth) acrylate; (meth) acrylonitrile, etc. Vinyl cyan compounds; polymerizable unsaturated fatty acids such as itaconic acid, maleic acid, fumaric acid, crotonic acid, cinnamic acid; N
-Methylmaleimide, N-ethylmaleimide, N-butylmaleimide, N-octylmaleimide, N-isopropylmaleimide, N-phenylmaleimide, Np-bromophenylmaleimide, N-o-chlorophenylmaleimide, N-cyclohexylmaleimide, etc. Maleimides; unsaturated carboxylic acid anhydrides represented by maleic anhydride, itaconic anhydride, citraconic anhydride, etc .; epoxy group-containing unsaturated compounds such as allyl glycidyl ether, glycidyl (meth) acrylate; allyl amine, ( Amino group-containing unsaturated compounds such as aminoethyl (meth) acrylate, aminopropyl (meth) acrylate, and aminostyrene; acrylamide-based compounds such as acrylamide and N-methylacrylamide; 2-hydroxyethyl-acrylate, 3- Mud propyl methacrylate, hydroxyl group-containing unsaturated compounds such as 4-hydroxy-2-butene and may also be used mixtures thereof.

In the production method of the present invention, an aromatic vinyl-based monomer (A), a zinc salt (B), and, if necessary, a polymerizable monomer capable of polymerizing with the above-mentioned (A) are used as polymerization components. Although it may be used, the impact strength of the resulting resin can be further improved by polymerizing these monomer components in the presence of the rubbery polymer.

Examples of such rubbery polymers include natural rubber (NR), acrylonitrile-butadiene rubber (NBR), styrene-butadiene rubber (SBR), polybutadiene rubber (BR), isoprene rubber (IR),
Chloroprene rubber (CR), butyl rubber (IIR), ethylene-propylene-non-conjugated diene rubber (EPDM),
Acrylic rubber (ACM, ANM), chlorinated polyethylene rubber (CSR), fluororubber (FKM), silicone rubber (Q), urethane rubber (AU, EU), polysulfide rubber (T), epichlorohydrin rubber (CO, ECO) , Chlorosulfonated polyethylene (CSM), norbornene rubber and / or their vulcanized polymeric materials and mixtures thereof may be added during the polymerization.

In the production method of the present invention, radical polymerization may be carried out by bulk polymerization using each of the above-mentioned components, and the method is not particularly limited, but specifically, batch polymerization method and continuous polymerization method are used. A method of carrying out by a conventional bulk polymerization method such as a polymerization method can be mentioned. When using a mixture of zinc salts (B), when styrene is used as a reaction solvent during the production, it can be directly used for radical polymerization, but when other organic solvent is used, It is preferable that the organic solvent is dried and removed before use.

The amount of the zinc salt mixture (B) used with respect to the aromatic vinyl monomer (A) is not particularly limited, but the amount of zinc is based on the number of moles of the aromatic vinyl monomer. If it is less than 0.01 mol%, the amount of the cross-linking agent will be small and the cross-linking effect will be weak. From these points, the amount of the zinc salt mixture (B) used is preferably in the range of 0.01 to 5 mol%, more preferably 0.05 to 1 mol%, and still more preferably 0.1 to 0. A range of 8 mol% is preferred.

The polymerization temperature is not particularly limited, but is usually in the temperature range of 60 ° C. to 250 ° C., preferably 70 ° C. to 220 ° C., among which the reaction rate is good and , 80 ℃ ~ 2 from the point of excellent heat removal efficiency
A temperature range of 00 ° C. is particularly preferred.

As the radical generating source, thermal initiation may be used, or an organic peroxide or the like may be used. The organic peroxide used here is not particularly limited, but for example, benzoyl peroxide, t-butylperoxy 2-ethylhexanoate,
1,1-bis (t-butylperoxy) -3,3,5-
Trimethylcyclohexane, 2,2-bis (4,4-di-t-butylperoxycyclohexyl) propane, t
-Butyl peroxybenzoate, di-t-butyl peroxide, etc. are mentioned.

As described above, the polymerization method can be carried out by a conventional batch-type bulk polymerization method, a continuous-type bulk polymerization method, or the like. Among them, continuous bulk polymerization is preferable from the viewpoint of productivity and cost.

In particular, in a continuous bulk polymerization line incorporating a tubular reactor in which a plurality of mixing elements having no moving parts are fixed, continuous bulk polymerization is carried out while static mixing is performed by the tubular reactor. By doing
It is preferable because a polymer having a high molecular weight and a high degree of crosslinking can be obtained.

As a particularly preferred continuous bulk polymerization method, the following methods are specifically mentioned. That is, a monomer component containing the components (A) and (B) as essential components is sent by a plunger pump to a circulation type polymerization line having a tubular reactor having a static mixing element and a gear pump. Then, while radical polymerization is carried out while circulating in the circulation polymerization line, a part of the radical polymerization is continuously sent to a non-circulation polymerization line in which tubular reactors having static mixing elements are installed in series, and in the non-circulation line. Main polymerization takes place. The polymerization liquid that has passed through the non-circulation line is continuously introduced into the devolatilization tank to remove unreacted monomers, and the desired thermoplastic ion crosslinked product can be obtained. The monomer removed in the devolatilization tank can be reused as a raw material monomer component again without being particularly purified.

Further, in the above-mentioned polymerization method, the flow rate of the mixed solution refluxing in the circulating polymerization line without flowing into the non-circulating polymerization line is set to F1 (liter / hour), and flows out from the circulating polymerization line to the non-circulating polymerization line. Flow rate of mixed solution F
Reflux non-ratio R = F1 at 2 (liter / hour)
/ F2 is preferably in the range of 3 to 15.

Further, as the plurality of mixing elements fixed inside the tubular reactor having the static mixing element used in the above-mentioned production method, for example, the division of the flow of the polymerization liquid flowing into the pipe and the changing of the flow direction are performed. , A method of mixing the polymerization liquid by repeating division and merging. As such a tubular reactor, for example, S
MX type and SMR type Sulzer type tubular mixers, Kenix type static mixers, Toray type tubular mixers and the like are preferable.

The organic solvent such as toluene and ethylbenzene may be used as a solvent not only in the continuous bulk polymerization method but also in the bulk polymerization. The amount of the organic solvent used is preferably in the range of 20% by weight or less in the reaction system, and more preferably 15% by weight or less. That is, if it exceeds 20% by weight,
It cannot be said to be bulk polymerization, and it becomes close to steam solution polymerization, and in this case, the obtained ionic crosslinked product is not dissolved and precipitates, making polymerization impossible. On the other hand, when the content is 15% by weight or less, the compatibility is further improved and the degree of crosslinking is increased, which is preferable.

Further, as a conventional additive, a molecular weight regulator such as α-methylstyrene or mercaptans represented by dodecyl mercaptan and a naphthene-based or paraffin-based mineral oil are added for the purpose of improving moldability. Good.

In the radical polymerization described in detail, usually,
In the devolatilization step, the nonvolatile components containing the monomer component can be removed to obtain a product, and the recovered monomer component can be reused as a monomer for polymerization. In the conventional method of performing radical polymerization using a large amount of the above-mentioned dimethylformamide, it is necessary to purify and separate the recovered monomer from dimethylformamide, which is cumbersome to introduce a separation device for that purpose. In the invention, the recovered monomer can be reused as a raw material monomer as it is without using such a separation device.

[0041]

EXAMPLES Next, the present invention will be described in more detail with reference to Examples and Comparative Examples.

Reference Example-1 [Preparation Method of Mixture (B) of Zinc Salt] (meth) acrylic acid and the carboxyl group-containing compound having 4 to 40 carbon atoms shown in Table 1 are shown in Table 1. After mixing in 60 g of toluene at a ratio and heating to 40 ° C., zinc oxide in an amount shown in Table 1 was gradually added with stirring.

After the addition of zinc oxide was completed, the mixture was stirred for 5 hours. Volatile components were removed from the obtained mixed liquid by a vacuum dryer, and methacrylic acid-based zinc salts (sample name MAA-0 to MAA-6) and acrylic acid-based zinc salts (sample name AA-0 to AA-2).
Was adjusted.

0.3% by weight of the (meth) acrylic acid zinc salt thus prepared was mixed with styrene, and then 90%
After heating to 90 ° C. and measuring the solubility in styrene at 90 ° C., insolubles were observed for the AA-0 and MAA-0 samples, and AA-1, AA-2 and MAA-1 were observed.
No insoluble matter was observed for the MAA-6 samples.

Reference Example-2 [Preparation method of styrene solution of zinc salt mixture] 2.16 g of acrylic acid, 2.82 g of oleic acid and 5 parts of styrene
After mixing in 6.2 g and heating to 35 ° C., zinc oxide 1.63
g was gradually added with stirring.

After the addition of zinc oxide was completed, the mixture was stirred for 5 hours and then allowed to stand to separate precipitated water to obtain 10% by weight of acrylic acid zinc salt.
A styrene solution (sample name AA-3) was prepared. No insoluble matter was observed in the styrene solution of the lead acrylate, which was prepared in this manner, and even when this styrene solution was mixed with styrene, it remained a transparent solution.

Reference Example-3 [Preparation method of dimethylformamide solution of zinc salt] 72.06 g of acrylic acid and 110.76 of dimethylformamide
After mixing with g, it is introduced into the reactor. Then 30
Total amount of zinc oxide 4 while adjusting the temperature so that it does not exceed ℃ 4
0.69 g was added slowly with stirring.

After the addition of zinc oxide was completed, the mixture was stirred for 3 hours and then allowed to stand still to obtain a solution of zinc acrylate in dimethylformamide (AA
-4) (hereinafter, abbreviated as "DMF solution") was prepared.

The DMF solution of this zinc acrylate salt was a transparent solution, but when the DMF solution of this zinc acrylate salt was mixed with styrene, it became cloudy and did not become a transparent solution.

[0050]

[Table 1]

[0051]

[Table 2]

[0052]

[Table 3]

Examples 1-14 and Comparative Examples 1-7 52 g of styrene, 0.125 g of t-butylperoxy (2-ethylhexanoate) as a polymerization catalyst, t-
Butyl peroxybenzoate (0.035 g) and each zinc salt (B) obtained in Reference Example were charged in a glass ampoule in an amount shown in Table 2, then sealed in a nitrogen stream, and sealed in an oil bath at 90 ° C. Polymerization was performed for 4 hours at 110 ° C. for 3 hours. After completion of the polymerization, the polymer was taken out and the solution viscosity was measured. The sample name and addition amount of the (meth) acrylic acid zinc salt and the measurement results of the solution viscosity are summarized in Table 2.

Example 15 The same method as in Example 1 except that 49.9 g of styrene and 2.34 g of a styrene solution of an acrylic acid zinc salt prepared in Reference Example-2 were used as a mixture (B) of zinc salt. Polymerization was carried out and the solution viscosity was measured.

Comparative Example 8 Polymerization was carried out in the same manner as in Example 1 except that 0.31 g of a zinc acrylate DMF solution prepared in Reference Example 3 as a zinc salt was used to measure the solution viscosity.

The melt viscosity was measured by the following method. That is, the polymer obtained by the polymerization reaction was dissolved in dry toluene so that the polymer concentration was 10% by weight, and the viscosity was measured at a temperature of 25 ° C. using a Canon Fenske viscometer.

Next, 5 g per 15 g of this toluene solution was added.
A drop of 35% hydrochloric acid was added and the solution viscosity after the hydrochloric acid treatment was measured. Such a hydrochloric acid treatment is intended to dissociate the crosslinked portion of the ionically crosslinked product with zinc, and shows that the higher the viscosity reduction rate before and after the hydrochloric acid treatment, the higher the degree of crosslinking.

The viscosity reduction rate was calculated by the following formula.

[0059]

[0060]

[Table 4]

[0061]

[Table 5]

[0062]

[Table 6]

[0063]

[Table 7]

[0064]

[Table 8]

[0065]

[Table 9]

From the above results, Comparative Example 1 and Example 1, Comparative Example 2 and Example 2, Comparative Example 3 and Example 3 and Comparative Example 4
According to a comparison between Example 4 and Example 4, the solubility of the acrylic acid zinc salt (B) in the monomer was improved by using 3 mol% of stearic acid, and the solution viscosity after polymerization and the decrease rate of the solution viscosity were large and the efficiency was high. It can be seen that ionic crosslinking is in progress.

Further, in Example 5, it is found that the same effect is obtained even when stearic acid is changed to oleic acid. On the other hand, from Comparative Example 5 and Example 6, Comparative Example 6 and Example 7, and Comparative Example 7 and Example 8, also in the methacrylic acid-based zinc salt (B), the ionic cross-linking proceeded similarly effectively. In Example 8, it can be seen that the same effect can be obtained even if the amount of stearic acid is significantly increased.

Examples 9 to 14 have 5 to 5 carbon atoms.
The results are obtained by variously changing the carboxyl group-containing compound of 40, and it can be seen that the ionic cross-linking proceeds efficiently in any of the examples.

In each of the examples, the solution viscosity of the sample in which the crosslinking point was dissociated with hydrochloric acid was much lower than the solution viscosity before the treatment with hydrochloric acid, and a polymer crosslinked by the metal salt was formed. It is understood that there is.

On the other hand, in Comparative Examples 1 to 6, the decrease in the solution viscosity before the treatment with hydrochloric acid and the decrease in the viscosity after the treatment were smaller than those in the examples, and only a part of the zinc (meth) acrylate used contributed to the ionic crosslinking. I understand.

In Example 15 and Comparative Example 8, the zinc salt (B) dissolved in styrene or DMF was used, but the ionic crosslinked product obtained in Example 15 was transparent. On the other hand, the ionic cross-linked product obtained in Comparative Example 8 was opaque, suggesting that a part of the zinc salt did not contribute to the reaction. The decrease in solution viscosity after the treatment with hydrochloric acid is lower than that in Example 15. It can be seen that the efficiency of ionic crosslinking is reduced.

Example 16 One reactive group (reactive group A) with a circulation line having a built-in static mixing device having an internal volume of 2 L, and two plug flow type reactive groups having an internal volume of 0.5 L (reactive group B, C) and a devolatilization equipment are arranged in series, and 290 g of styrene per hour, 25 g of toluene, and sample AA-1 0.7 are used.
5 g was continuously supplied, and the temperature of each reactive group was 138 ° C. for the reactive group A, 150 ° C. for the reactive group B, and 16 ° C. for the reactive group C.
The temperature was kept at 0 ° C., 250 g of the polymer was obtained per hour, and the solution viscosity was measured. The results are shown in Table-3.

Comparative Example 9 A polymer was obtained in the same manner as in Example 14 except that the sample AA-1 was changed to the sample AA-0, and the solution viscosity was measured. The results are shown in Table-3.

[0074]

[Table 10]

[0075]

EFFECTS OF THE INVENTION According to the present invention, there are no safety and health problems and no complication in the process, the degree of crosslinking of the obtained thermoplastic ionic crosslinked product is high, and the reuse of raw materials is easy. It is possible to provide a method for producing a thermoplastic ionic crosslinked product.

Claims (8)

[Claims] 1. A mixture of an aromatic vinyl monomer (A) and a zinc salt containing (meth) acrylic acid and a carboxyl group-containing compound having 5 to 40 carbon atoms as an acid component (B). A process for producing a thermoplastic ionic crosslinked product, which comprises bulk polymerization in a system substantially free of dimethylformamide. 2. An organic solvent capable of dissolving a zinc salt of di (meth) acrylic acid, and the content of the organic solvent in dissolving the zinc salt in the aromatic vinyl monomer (A) as a solution of the zinc salt. A mixture of the aromatic vinyl-based monomer (A) and the mixture (B), which is substantially free of an organic solvent compatible with the aromatic vinyl-based monomer (A) within a range of 20% by weight or less. The method according to claim 1, wherein the reaction is carried out with. 3. A continuous bulk polymerization line incorporating a tubular reactor in which a plurality of mixing elements having no moving parts are fixed to an aromatic vinyl monomer (A) and a mixture (B). 3. The production method according to claim 1, wherein the bulk polymerization is continuously carried out while statically mixing with the tubular reactor. 4. The amount of the mixture (B) used is the monomer (A).
The production method according to claim 1, 2 or 3, wherein the amount of zinc is 0.01 to 5 mol% with respect to the number of moles. 5. The production method according to claim 1, 2, 3 or 4, wherein the content of (meth) acrylic acid in the acid component constituting the mixture (B) is 25 to 99 mol%. 6. The mixture (B) is obtained by reacting with a zinc compound in the coexistence of (meth) acrylic acid and a carboxylic xyl-containing compound having 5 to 40 carbon atoms.
The manufacturing method according to any one of 1. 7. The zinc compound is zinc oxide.
The manufacturing method described. 8. The production method according to claim 1, wherein the aromatic vinyl monomer (A) and the mixture (B) are radically polymerized in a temperature range of 60 ° C. to 250 ° C.