JP2001106715A - Production of ultrahigh molecular weight polymer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ultrahigh molecular weight (co)polymer having a weight- average molecular weight of >=5,000,000 and a Mw/Mn ratio of >=2.0 on the emulsion polymerization of a vinylic monomer. SOLUTION: This method for producing an ultrahigh molecular weight polymer comprises the emulsion polymerization of at least one kind of radical- polymerizable vinylic monomer. Therein, 0.0005 to 0.05 pt.wt. of an organic peroxide or a persulfate constituting a redox-based polymerization initiator, 0.1 to 5.0 pts.wt. of an activator, 0.005 to 0.1 pt.wt. of a chelating agent, 0.001 to 0.1 pt.wt. of a reducing agent, 3 to 60 pts.wt. of an emulsifier, and 1,000 to 15,000 pts.wt. of water are used per 100 pts.wt. of the total amount of the monomers.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing an ultrahigh molecular weight polymer by an emulsion polymerization method.

[0002]

2. Description of the Related Art It is well known that (co) polymers such as polystyrene and acrylonitrile-styrene copolymer are conventionally produced industrially by suspension polymerization, bulk polymerization, emulsion polymerization and the like. In particular, in emulsion polymerization, a polymer having a relatively high molecular weight was easily obtained as compared with other polymerization methods. However, in the conventional production method, the weight average molecular weight (Mw) is tens of thousands to
It was not common to produce a polymer having a weight average molecular weight of 5,000,000 or more by an emulsion polymerization method, which is a polymer of 2,000,000. In particular, a polymer such as polystyrene having an ultrahigh molecular weight polymer and having a small molecular weight distribution of Mw (weight average molecular weight) / Mn (number average molecular weight) has been obtained (JP-A-52-84269, JP-A-57-42703), and a (co) polymer having a vinyl monomer unit such as a polystyrene or an acrylonitrile-styrene copolymer having an ultrahigh molecular weight polymer having a large Mw / Mn molecular weight distribution has been obtained. Did not.

[0003]

DISCLOSURE OF THE INVENTION The present inventors have found that when emulsion polymerization of a vinyl monomer or a monomer mixture thereof is carried out, an ultrahigh molecular weight polymer and a molecular weight distribution having a larger Mw / Mn are obtained. As a result of intensive studies to solve the problem that the polymer having was not obtained, the weight average molecular weight is 5,000,000 or more,
Further, it has been found that a polymer having Mw / Mn of 2.0 or more can be obtained.

[0004]

SUMMARY OF THE INVENTION The present invention relates to a method for reducing the amount of a redox polymerization initiator and the method of addition, the amount of an emulsifier and the amount of water used for emulsification when emulsion-polymerizing a vinyl monomer or a monomer mixture thereof. It can be achieved by controlling and polymerizing at a specific polymerization temperature. In other words, when emulsion-polymerizing a vinyl monomer and its monomer mixture, the amount of the radical initiator is controlled by making the polymerization initiator constituting the redox polymerization initiator a small amount, and forming the redox catalyst. The growth rate of the vinyl monomer was controlled by controlling the amount and the total amount of the activator, chelating agent, and reducing agent to be added, and the amount of micelles generated by the emulsifier was controlled.

That is, the present invention relates to a method of emulsion-polymerizing at least one kind of a vinyl monomer which can be radically polymerized, wherein a redox-based polymerization initiator is added to 100 parts by mass of the total amount of the monomer. 0.0005 to 0.05 parts by mass of an organic peroxide or a persulfate, 0.1 to 5.0 parts by mass of an activator, and 0.005 to 5 parts by mass of a chelating agent.
0.1 parts by mass, 0.001 to 0.1 parts by mass of a reducing agent, 3 to 60 parts by mass of an emulsifier, and more than 1,000 parts by mass of water.
This is a method for producing an ultrahigh molecular weight polymer having a weight average molecular weight of 5,000,000 or more and Mw / Mn of 2.0 or more using 5,000 parts by mass.

Hereinafter, the present invention will be described in detail. Examples of the vinyl monomer used in the present invention include aromatic vinyl monomers such as styrene, α-methylstyrene, dimethylstyrene and vinyltoluene; vinyl cyanide monomers such as acrylonitrile, methacrylonitrile and fumaronitrile; Methacrylate monomers such as methyl acrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, phenyl methacrylate, benzyl methacrylate, isobornyl methacrylate, methyl acrylate, ethyl acrylate, Propyl acrylate, butyl acrylate, acrylic acid-2
-Ethyl hexyl, acrylate monomers such as cyclohexyl acrylate, maleic acid, itaconic acid, unsaturated dicarboxylic anhydride monomers such as citraconic anhydride, maleimide, N-methylmaleimide, N-butylmaleimide, Examples include unsaturated dicarboxylic acid imide compound monomers such as N-phenylmaleimide and N-cyclohexylmaleimide. These vinyl monomers can be used alone or in combination of two or more.

The redox polymerization initiator used in the present invention comprises a polymerization initiator and a redox catalyst comprising an activator, a chelating agent and a reducing agent. As the polymerization initiator used in the present invention, water-soluble and oil-soluble organic peroxides and persulfates can be used. Examples of the organic peroxide include t-butyl hydroperoxide, cumene hydroperoxide, benzoyl peroxide, lauroyl peroxide, and the like. Examples of the persulfate include potassium persulfate and ammonium persulfate.

The organic peroxide or persulfate used in the emulsion polymerization is 0.0005 to 0.05 parts by mass, preferably 0.1 to 0.05 parts by mass.
001 to 0.01 parts by mass. When the amount of the organic peroxide or persulfate is less than 0.0005 parts by mass per 100 parts by mass of at least one kind of the vinyl monomer, the polymerization becomes difficult to start, and the weight average molecular weight is more than 0.05 parts by mass. Cannot exceed 5,000,000. The polymerization initiator can be added all at once or dividedly, or a part of the used amount can be added all at once and the remainder can be added separately. In the case of the divisional addition method, divisional or continuous addition is performed according to the target molecular weight. In the present invention, the term "split" means to add a specified amount of a polymerization initiator evenly at regular intervals. Also, dispensing refers to a method of adding continuously within a certain time.

As activators constituting the redox catalyst used in the present invention, glucose, dextrose, formaldehyde sodium sulfoxylate, sulfite (eg, sodium sulfite), bisulfite (eg, sodium bisulfite), thiosulfate ( For example, sodium thiosulfate) can be used. The activator is used in an amount of 0.1 to 5.0 parts by mass, preferably 0.3 to 3.0 parts by mass, more preferably more than 0.5 part by mass and 2.0 parts by mass, based on at least one kind of the vinyl monomer. Part or less. If the amount of the activator is less than 0.1 part by mass per 100 parts by mass of at least one vinyl monomer, the polymerization reaction does not proceed and the molecular weight does not increase. If the amount is more than 5.0 parts by mass, an ultra-high molecular weight can be obtained, but the increase in the molecular weight is small and the effect of addition is small for the added amount.

As a chelating agent, hexacyanoiron (I
II) Potassium, ethylenediamine acetate, etc.
Ferrous sulfate, sodium pyrophosphate, sodium phosphate, copper sulfate and the like can be used as the reducing agent. An appropriate amount is used according to the combination of each initiator. The chelating agent is used in an amount of 0.005 to 0.1 part by mass, preferably 0.01 to 0.1 part by mass, per 100 parts by mass of at least one of the vinyl monomers.
08 parts by mass. The reducing agent is used in an amount of 0.001 to 0.1 part by mass, preferably 0.005 to 0.05 part by mass, per 100 parts by mass of at least one of the vinyl monomers. When the amount of the chelating agent is less than 0.005 part by mass or the amount of the reducing agent is less than 0.001 part by mass per 100 parts by mass of the vinyl monomer, the polymerization reaction does not proceed and the molecular weight is large. No. Further, even if the amount of the chelating agent or the reducing agent is more than 0.1 part by mass, an ultra-high molecular weight can be obtained, but the increase in the molecular weight is small for the added amount, and the effect of addition is small.

The total amount of the redox catalyst to be added is 0.1 to 100 parts by mass of at least one vinyl monomer.
The amount is controlled in the range of 11 to 5.2 parts by mass, preferably 0.3 to 2.0 parts by mass. If the total amount of the added redox catalyst is less than 0.11 part by mass, the polymerization reaction does not proceed and the molecular weight does not increase. Further, even if the amount is more than 5.2 parts by mass, the change in the value of the molecular weight is small and the effect of addition is small for the added amount. The redox catalyst is added all at once in the early stage of the polymerization, or divided or divided.

The emulsifier used in the emulsion polymerization of the present invention may be a known emulsifier, and is not particularly limited.
For example, anionic surfactants such as fatty acid salts, alkyl sulfate salts, alkyl benzene sulfonate salts, alkyl acid ester salts, alkyl diphenyl ether sulfonate salts, and polyoxyethylene alkyl ethers, polyoxyethylene fatty acid esters, and sorbitan fatty acid esters And nonionic surfactants such as glycerin fatty acid esters, and cationic surfactants such as alkylamine salts. These emulsifiers can be used alone or in combination.

Further, in the present invention, the emulsifier is used in an amount of 3 to 60 parts by mass, preferably 5 to 30 parts by mass, based on 100 parts by mass of at least one vinyl monomer. If the amount of the emulsifier is less than this, the desired ultrahigh molecular weight polymer will not be obtained. Outside this range, the polymer becomes an ultrahigh molecular weight polymer, but the molecular weight of the polymer is not stable.

In the ordinary emulsion polymerization, ion-exchanged water or pure water can be used, but if it exceeds 1,000 parts by mass and exceeds 15.0 parts by mass for at least 100 parts by mass of the vinyl monomer.
00 parts by mass or less, preferably more than 1,000 parts by mass
The range is not more than 000 parts by mass. The amount of water is 100,000 parts per 100 parts by mass of at least one vinyl monomer.
When the amount is less than 0 parts by mass, the polymer becomes an ultrahigh molecular weight polymer, but the molecular weight distribution is narrow and Mw / Mn becomes small, making it difficult to obtain the target ultrahigh molecular weight polymer. It becomes difficult to control the temperature. On the other hand, when the amount exceeds 15,000 parts by mass, the polymerization reaction hardly proceeds.

No chain transfer agent or molecular weight modifier is used to make an ultrahigh molecular weight polymer. In addition, it is desired that the polymerization temperature at the time of emulsion polymerization be in the range of -10 to 80C, preferably 0C to 60C.

In the method for recovering an ultrahigh molecular weight polymer according to the method of the present invention, for example, the obtained polymer latex is cooled to room temperature, and an acid such as sulfuric acid, hydrochloric acid, phosphoric acid or the like, or aluminum chloride, calcium chloride, With electrolytes such as magnesium sulfate, aluminum sulfate, and salts such as calcium acetate,
After the polymer is precipitated by acid coagulation or salting out, the polymer can be further filtered, washed and dried. In addition, a known recovery method can be used, such as recovering the obtained polymer latex by a technique such as spray drying or freeze drying.

When the ultrahigh molecular weight polymer of the present invention is used as a modifier for polystyrene, styrene-acrylonitrile copolymer, ABS resin, MBS resin, etc., the aromatic vinyl monomer is 60% by mass or more. Thus, a polymer having a vinyl cyanide monomer content of 40% by mass or less is preferably produced.

The ultrahigh molecular weight polymer of the present invention has a weight average molecular weight of 5,000,000 or more and a ratio of Mw to Mn (M
(w / Mn) is a polymer having a molecular weight distribution of 2.0 or more, and a polymer having Mw / Mn of more than 2.5 is preferably produced. When mixed as a modifier for the above resin, the weight average molecular weight is preferably at least 6.7 million, more preferably over 7.6 million, and Mw / Mn is at least 2.7, more preferably 3.0-
Those which are 15 are preferably produced.

The polymerized latex of the present invention can be used alone as a film or a resin. Further, it can be mixed with a latex obtained by other known polymerization methods. These single resins and resin compositions are excellent in vacuum molding and blow molding properties, and exhibit excellent properties such as prevention of uneven thickness in films and sheets.

[0020]

The present invention will be described in detail with reference to the following examples and comparative examples, but the present invention is not limited to the following examples.

Each physical property in each example and comparative example was measured as follows. (1) Weight average molecular weight and Mw / Mn Weight average molecular weight and Mw / M of the ultrahigh molecular weight polymer, styrene polymer and styrene copolymer obtained in the present invention
n was measured using a gel permeation chromatography (GPC) apparatus under the following conditions, and the molecular weight is a value in terms of polystyrene. Apparatus; “SYSTEM-21” column, manufactured by Tosoh Corporation; PLgel MIXED-B temperature; 40 ° C. solvent; tetrahydrofuran detection; RI concentration; 0.2 mass% injection amount; 100 μl calibration curve; standard polystyrene (manufactured by Polymer Laboratories) )use

Example 1 A-1: 14,000 parts by mass of ion-exchanged water, higher fatty acid soap in a 5-liter stainless steel reactor equipped with a stirrer, a heating / cooling device, a thermometer, and a raw material addition device under a nitrogen atmosphere. Raw materials of 10 parts by mass, 30 parts by mass of acrylonitrile and 70 parts by mass of styrene were charged, and a redox catalyst (0.01 parts by mass of ferrous sulfate, 0.02 parts by mass of sodium ethylenediaminetetraacetate, 0.6 parts by mass of sodium formaldehyde sulfoxylate) Parts), while maintaining the internal temperature at 50 ° C. and continuously dropping 0.01 parts by mass of potassium persulfate,
Emulsion polymerization was carried out by heating and stirring for 4 hours and 30 minutes, and the reaction was terminated by cooling. The obtained latex is dropped into methanol,
After filtration and drying, polymer A-1 was obtained. Table 1 shows the results.

Example 2 A-2: The reaction vessel used in Example 1 was placed under a nitrogen atmosphere.
8,000 parts by mass of ion-exchanged water, 15 parts by mass of higher fatty acid soap, 30 parts by mass of methyl methacrylate, and styrene 7
0 parts by mass of the raw materials were charged, and a redox catalyst (0.02 parts by mass of ferrous sulfate, 0.03 parts by mass of sodium ethylenediaminetetraacetate, 1.0 part by mass of sodium formaldehyde sulfoxylate) was added, and the internal temperature was 50 ° C. , And while continuously dropping 0.02 parts by mass of t-butyl peroxyacetate, the mixture was heated and stirred for 4 hours and 30 minutes to carry out emulsion polymerization, and the reaction was terminated by cooling. The obtained latex was dropped into methanol, filtered and dried to obtain a polymer A-2.
Table 1 shows the results.

Example 3 A-3: The reaction vessel used in Example 1 was placed under a nitrogen atmosphere.
2,000 parts by mass of ion-exchanged water, 20 parts by mass of a higher fatty acid soap, 25 parts by mass of acrylonitrile and 75 parts by mass of styrene were charged, and a redox catalyst (ferrous sulfate 0.1 part) was added.
03 parts by mass, ethylenediaminetetraacetic acid 0.05
Parts by mass and 1.5 parts by mass of sodium formaldehyde sulfoxylate) were added thereto, and the mixture was heated and stirred for 4 hours and 30 minutes while maintaining the internal temperature at 40 ° C. and continuously dropping 0.006 parts by mass of t-butyl hydroperoxide. Perform polymerization,
The reaction was terminated by cooling. The obtained latex was dropped into methanol, filtered and dried to obtain a polymer A-3. Table 1 shows the results.

Comparative Example 1 B-1 80 parts by weight of ion-exchanged water and 2.0 parts by weight of a higher fatty acid soap were charged in a nitrogen atmosphere in the reaction vessel used in Example 1, and a redox catalyst (ferrous sulfate 0.1%) was added. 005 parts by mass, 0.01 parts by mass of sodium ethylenediaminetetraacetate, 0.3 parts by mass of sodium formaldehyde sulfoxylate
Parts by mass), the mixture was maintained at an internal temperature of 70 ° C., and while continuously adding 30 parts by mass of acrylonitrile, 70 parts by mass of styrene, and 0.1 parts by mass of potassium persulfate, the mixture was heated and stirred for 4 hours and 30 minutes to carry out emulsion polymerization. The reaction was terminated by cooling. The obtained latex was dropped into methanol, filtered and dried to obtain a polymer B-1. Table 1 shows the results.

Comparative Example 2 B-2: 400 parts by mass of ion-exchanged water and 5.0 parts by mass of a higher fatty acid soap were charged into a reaction vessel used in Example 1 under a nitrogen atmosphere, and a redox catalyst (0.5 part by mass of glucose) was added. ,
0.5 parts by mass of sodium pyrophosphate, ferrous sulfate 0.0
1 part by mass), 100 parts by mass of styrene, and 0.1 part by mass of cumene hydroperoxide were added, and the mixture was maintained at an internal temperature of 40 ° C., heated and stirred for 5 hours to carry out emulsion polymerization, and cooled to terminate the reaction. The obtained latex was dropped into methanol, filtered and dried to obtain a polymer B-2. Table 1 shows the results.

[0027]

[Table 1]

[0028]

According to the production method of the present invention, an ultra-high molecular weight polymer can be obtained with extremely high precision, so that it is suitable as an industrial method for producing an ultra-high molecular weight polymer.

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference) 4J011 KA04 KA08 KA12 KA15 KB07 KB29 4J015 CA03 CA05 CA07 CA14 4J100 AB02P AB03P AB04P AK31P AK32P AL03P AL04P AL08P AL11P AM02P AM07P AM43P AM45P AM47P AM48P BC04 FA04 BC08

Claims (3)

[Claims] 1. A method of emulsion-polymerizing at least one kind of vinyl monomer capable of undergoing radical polymerization, wherein an organic compound constituting a redox-based polymerization initiator is added to 100 parts by mass of the total amount of the monomer. 0.0005 to 0.05 parts by mass of peroxide or persulfate, and 0.1 to 5.
0 parts by mass, 0.005 to 0.1 parts by mass of a chelating agent, 0.001 to 0.1 parts by mass of a reducing agent, 3 to 60 parts by mass of an emulsifier, and more than 1 000 parts by mass of water to 15,000. A weight-average molecular weight of 50 or less,
A method for producing an ultrahigh molecular weight polymer having a molecular weight of not less than 10,000 and Mw (weight average molecular weight) / Mn (number average molecular weight) of not less than 2.0. 2. The method for producing an ultrahigh molecular weight polymer according to claim 1, wherein the activator constituting the redox polymerization initiator is more than 0.5 parts by mass and not more than 2.0 parts by mass. 3. The weight average molecular weight obtained by the method for producing an ultrahigh molecular polymer according to claim 1 or 2 is 5,000,000 or more,
And an ultrahigh molecular weight polymer having a Mw / Mn of more than 2.5.