JP3197353B2 - Method for producing degradable polymer dispersion - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing a degradable polymer dispersion. More specifically, the present invention relates to a method for producing a dispersion by mixing a specific polymer compound and a plasticizer while heating.

[0002]

2. Description of the Related Art The use of degradable polymers as binders, the production of degradable films, and the use of degradable adhesives are widely performed. Usually, degradable polymers are dissolved in solvents. It is used in the state where it was done. As a solvent, a decomposable polymer is not dissolved in water, and is used by dissolving it in an organic solvent.

[0003]

However, since the organic solvent of the decomposable polymer solution is removed by evaporation during use, it is necessary to make the solvent harmless or to recover it. In some cases, it is necessary to use explosion-proof equipment. There are problems such as.

[0004]

Means for Solving the Problems The present inventors have solved the above problems, and have intensively searched for a method for producing a degradable dispersion liquid without using an organic solvent, and have completed the present invention.

That is, the present invention relates to a method for preparing a poly-α-methylstyrene or polyalkylene carbonate ,
α-methylstyrene or polyalkylene carbonate
A method for producing a degradable polymer dispersion, comprising dispersing in water under heating at a temperature not lower than the temperature at which the mixture of the polymer and the plasticizer is plasticized .

In the present invention, a high molecular weight polymer obtained by anionic polymerization of α-methylstyrene is used as polyα-methylstyrene, and other polystyrene-based monomers are used as long as the decomposability is not impaired. Polymerized, for example, when styrene is used, 50 mol% or less,
And a number average molecular weight of about 5,000 to 100,000, preferably about 10,000 to 500,000. Examples of the polyalkylene carbonate include those obtained by copolymerizing an alkylene oxide having 2 to 10 carbon atoms and carbon dioxide using a catalyst, and having a molecular weight of 1,000 to 100,000, usually about 5,000 to 500,000. Available.

In the present invention, the above-mentioned polymer is used by mixing with a plasticizer. Here, as the plasticizer, a compound having a low melting point and a relatively high boiling point is used, and an ester of phthalic acid, an ester of phosphoric acid, and an oligomer of α-methylstyrene are used. The usage ratio of the polymer and the plasticizer is generally about 200 to 1 per 100 of the polymer.

Thus, the mixing with the plasticizer can be performed prior to the mixing with the water, but if a device capable of sufficiently mixing is used, the mixing with the water may be performed at the same time. When mixing with water, a small amount of a surfactant and a water-soluble polymer are preferably present. Here, the amount of the surfactant used is 0.01 to 5, usually 0.1
About 2 and the total of the polymer and the plasticizer is 1 to 10
0, especially about 5 to 50. Heating is essential for mixing, and the heating temperature is equal to or higher than the temperature at which the mixture of the polymer and the plasticizer is plasticized, and is performed under pressure as necessary. Usually, it is carried out at 50 to 300 ° C.
At this time, it is also possible to use sodium hydroxide, potassium hydroxide, calcium hydroxide, sodium phosphate, sodium dihydrogen phosphate, potassium phosphate, potassium dihydrogen phosphate or the like to stabilize the aqueous emulsion. . As the surfactant, nonionic and anionic surfactants can be used, and various surfactants are available on the market. Specifically, sodium alkylbenzene sulfonate, sodium alkyl sulfonate, polyethylene oxide alkyl ether, polyethylene oxide alkylbenzene Ether is exemplified. In order to obtain a dispersion, the mixing is preferably performed under strong stirring, and various types of such devices are already known and can be obtained on the market.

[0009]

The present invention will be further described with reference to examples.

Example 1 Poly-α-methylstyrene 12 having a number average molecular weight of 120,000 was obtained by polymerizing α-methylstyrene using butyllithium.
g and 8 g of a trimer of α-methylstyrene were added to a solution of 1 g of sodium dodecylbenzenesulfonate in 100 ml of water, and the mixture was stirred well at 150 ° C. using an autoclave. After the temperature was lowered to 30 ° C. with stirring, the dispersion was taken out to obtain a uniformly dispersed liquid. This dispersion was applied to a glass plate and dried to form a film having a thickness of 3 μm. 38
When treated at 0 ° C. for 1 hour, the coating film was completely scattered.

Example 2 An oligomer (molecular weight of about 45) obtained by hydrolyzing polypropylene carbonate (molecular weight: 80,000) obtained by polymerizing propylene oxide and carbon dioxide with an aqueous sodium hydroxide solution.
00) Except that 20 g and 2 g of dioctyl phthalate were used, the same procedure was performed as in Example 1 to obtain a homogeneous dispersion.
A uniform film was obtained by applying the liquid.

[0012]

By carrying out the method of the present invention, an aqueous dispersion of a degradable polymer is obtained, which is extremely valuable industrially.

Claims (1)

(57) [Claims] 1. A poly-α-methylstyrene or polyalkylene carbonate and a plasticizer are mixed with poly-α-methylstyrene.
Mixture of plasticizer and ren or polyalkylene carbonate
A method for producing a degradable polymer dispersion, comprising dispersing in water under heating at a temperature not lower than the temperature at which the compound is plasticized .