METHOD FOR PREPARING POLYMERIZATION INITIATOR COMPOSITION

Abstract

The present disclosure provides a method for preparing a polymerization initiator composition, including (a) a step of mixing water and a water-soluble initiator to prepare an aqueous initiator solution having a concentration of 1 to 10%; and (b) a step of activating the aqueous initiator solution, wherein the step of activating is performed by (b-1) a step of heat treating the aqueous initiator solution for 0.5 to 4.5 hours at a temperature of 48 to 62° C.; and (b-2) a step of treating the aqueous initiator solution to achieve pH of 1 to 7, where the steps above are performed in no particular order.

Claims

1. A method for preparing a polymerization initiator composition, the method comprising: (a) mixing water and a water-soluble initiator to prepare an aqueous initiator solution having a concentration of 1 to 10%; and (b) activating the aqueous initiator solution, performed by (b-1) heat treating the aqueous initiator solution for

0. 5 hours to 4.5 hours at a temperature of 48 to 62° C.; and (b-2) treating the aqueous initiator solution to achieve pH of 1 to 7, wherein the steps above are performed in no particular order.

2. The method of claim 1, wherein the water-soluble initiator is one or more selected from the group consisting of potassium persulfate, sodium persulfate and ammonium persulfate.

3. The method of claim 1, wherein the aqueous initiator solution has a concentration of 3 to 6%.

4. The method of claim 1, wherein, in the step of (b-1), the aqueous initiator solution is heat treated at a temperature of 50 to 60° C.

5. The method of claim 1, wherein, in the step of (b-1), the aqueous initiator solution is heat treated for 1 to 4 hours.

6. A method for preparing a vinyl chloride-based polymer, the method comprising: polymerizing a vinyl chloride-based monomer in the presence of the initiator composition prepared according to claim 1.

7. The method of claim 6, wherein the polymerization is performed at a polymerization temperature of 40 to 65° C.

8. The method of claim 6, wherein the polymerization is emulsion polymerization.

Description

EXAMPLES

[0056] Hereinafter, the present invention will be explained in more detail referring to Examples and Experimental

[0057] Examples. However, the Examples and Experimental Examples are only for illustrating the present invention and the scope of the present invention is not limited thereto.

Example 1

Activation of Water-Soluble Initiator

[0058] To a reactor tank, 10 g of potassium persulfate (KPS) as a water-soluble initiator and 240 g of water were injected and mixed to prepare a 4% aqueous solution. In the reactor tank, the aqueous solution was heat treated while keeping stirring force at a temperature of 50° C. for 60 minutes using a hot plate.

[0059] After the heat treatment, a 1% HCl aqueous solution and a 5% NaOH aqueous solution were added in 0.01-0.1 phm, respectively, to treat the aqueous solution to achieve pH in a range of 1 to 4.

Preparation of Vinyl Chloride-Based Polymer

[0060] In the reactor tank to which the activated aqueous solution of the water-soluble initiator was injected, a paste

[0061] PVC was polymerized by an emulsion polymerization method according to the order below. First, 180 kg of polywater (100 phm based on vinyl chloride monomer) and 18 kg of a first emulsifier (0.01 phm based on vinyl chloride monomer) were injected thereto, followed by elevating the temperature to 50° C. Then, 180 kg of a vinyl chloride monomer was injected, and 1800 g of a second emulsifier (1 phm based on vinyl chloride monomer) for stabilizing particles during reaction was injected, and the reaction was performed until a conversion ratio reached 90%.

Examples 2 to 7 and Comparative Examples 1 to 11

[0062] Vinyl chloride-based polymers according to Examples 2 to 7 and Comparative Examples 1 to 11 were obtained by the same method as in Example 1 except for changing the activation conditions of water-soluble initiators as shown in Table 1 below.

Experimental Example 1: Evaluation of Overall Results

[0063] As each polymerization result of the Examples and the

[0064] Comparative Examples, polymerization time and whether normal polymerization is performed or not are also shown in Table 1 below.

[0065] 1) Polymerization time: Polymerization time was obtained by measuring a time from the injection of polymerization supplementary and after elevating the temperature to a polymerization temperature to a point where a reaction pressure of 3.5 KG/cm.sup.2.

[0066] 2) Deciphering whether normal polymerization was performed or not: Whether or not normal polymerization was performed was evaluated by checking the aggregate through the aggregation of latex with the naked eye and was evaluated by O if aggregate was not confirmed, X if aggregate was confirmed, and X if latex was not obtained due to explosive reaction, etc.

TABLE-US-00001 TABLE 1 Heat treatment Normal temperature Heat treatment Solvent polymerization (° C.) time (hr) pH Time (hr) or not Example 1 50 1 2.5 5 hr 43 min ∘ Example 2 50 1 4.5 6 hr 57 min ∘ Example 3 60 1 6.5 8 hr 30 min ∘ Example 4 55 1 6.5 8 hr 53 min ∘ Example 5 50 2 6.5 8 hr 53 min ∘ Example 6 50 3 6.5 8 hr 30 min ∘ Example 7 50 4 6.5 8 hr 12 min ∘ Comparative 50 1 — 14 hr 27 min ∘ Example 1 Comparative — 0 4.5 9 hr 20 min ∘ Example 2 Comparative — — 6.5 15 hr 0 min ∘ Example 3 Comparative 20 1 6.5 15 hr 20 min ∘ Example 4 Comparative 10 1 6.5 15 hr 20 min ∘ Example 5 Comparative 50 1 7.5 15 hr 10 min ∘ Example 6 Comparative 50 1 0.5 — X (aggregate) Example 7 Comparative 65 1 6.5 6 hr 28 min ∘ Example 8 Comparative 70 1 6.5 — X (explosive Example 9 reaction) Comparative 45 1 6.5 17 hr 40 min ∘ Example 10 Comparative 50 6 6.5 10 hr 20 min ∘ Example 11

[0067] Referring to Table 1, it could be confirmed polymerization was completed normally within a polymerization time of 5 hours to 9 hours for Examples 1 to 7, but the polymerization time was significantly long for Comparative Example 1 in which only heat treatment was performed, Comparative Example 2 in which only pH treatment was performed, Comparative Example 3 in which activation was not performed, Comparative Example 4 in which pH conditions during activation were high, and Comparative Example 8 in which heat treatment temperature was low. In addition, it could be confirmed from the results that in Comparative Example 5 in which pH conditions were too low, aggregation was generated in the polymer latex state thus prepared, and in Comparative Example 7 in which temperature conditions were too high, explosive reaction occurred.

Experimental Example 2: Evaluation of Plastisol Performance

[0068] In order to compare and analyze the physical properties of each vinyl chloride-based polymer prepared according to Example 1 to Example 7 and Comparative Example 1 to Comparative Example 11, 100 g of each vinyl chloride-based polymer and 120 g of dioctyl phthalate (DOP) were stirred using Werke mixer (EUROSTAR IKA) in 800 rpm for 10 minutes to prepare each plastisol.

[0069] The viscosity and heat resistance (white index) of the plastisol thus prepared were measured by the methods below, and the results are shown in Table 2 below.

[0070] 1) Viscosity: The viscosity of each plastisol was measured using BrookField viscometer (BrookField Co., LV-DV 1 Prime viscometer) at 25° C. with number 7 spindle in 20 rpm.

[0071] 2) Heat resistance: Each plastisol was applied on a release paper, coated using a bar with 0.5 mm, and dried using Mathis oven at 150° C. for 45 seconds to manufacture a pregelling sheet, and then was heated at 200° C. for 100 seconds. According to ASTM E313-73, using SPECTRO PHOTO METER (CM-700d, KONICA MINOLTA), white index was measured.

TABLE-US-00002 TABLE 2 Normal Heat polymerization Viscosity resistance Time or not (Pa .Math. s) (WI) Example 1 5 hr 43 min ∘ 110 53 Example 2 6 hr 57 min ∘ 115 52.7 Example 3 8 hr 30 min ∘ 112 52.4 Example 4 8 hr 53 min ∘ 111 52.4 Example 5 8 hr 53 min ∘ 114 52.9 Example 6 8 hr 30 min ∘ 116 53.1 Example 7 8 hr 12 min ∘ 114 50.9 Comparative 14 hr 27 min ∘ 111 51.4 Example 1 Comparative 9 hr 20 min ∘ 111 52.1 Example 2 Comparative 15 hr 0 min ∘ 113 53.1 Example 3 Comparative 15 hr 20 min ∘ 112 52.1 Example 4 Comparative 15 hr 20 min ∘ 112 52.7 Example 5 Comparative 15 hr 10 min ∘ 119 52.3 Example 6 Comparative — X (aggregate) — — Example 7 Comparative 6 hr 28 min ∘ 350 45 Example 8 Comparative — X (explosive — — Example 9 reaction) Comparative 17 hr 40 min ∘ 102 51.5 Example 10 Comparative 10 hr 20 min ∘ 105 51.7 Example 11

[0072] From the results of Table 2, it could be confirmed that in Comparative Example 6 in which the activation of a water-soluble initiator was performed at a temperature of 65° C., the reaction time was decreased but viscosity was markedly increased, and since low white index was shown by a heat resistance test, heat resistance was degraded. In addition, in Comparative Examples 1 to 4, 8 and 9, it was confirmed that the results on viscosity and heat resistance were relatively good, but polymerization time was excessively long.

[0073] However, it could be confirmed that in Examples 1 to according to the present invention, polymerization was completed in a normal level, the generation of aggregation or the phenomenon of explosive reaction were not shown, and the viscosity or heat resistance of the plastisol was also excellent. That is, in case of performing polymerization reaction by activating an initiator according to an embodiment of the present invention, heat resistance may be secured to an excellent degree as well as polymerization productivity, stability, and the processability of plastisol processing.