WO2006009377A1

WO2006009377A1 - Solvent for polymerization and method for preparing polymer using the same

Info

Publication number: WO2006009377A1
Application number: PCT/KR2005/002310
Authority: WO
Inventors: Kwang Rim CHOI
Original assignee: Sung Rim Chemical
Priority date: 2004-07-19
Filing date: 2005-07-18
Publication date: 2006-01-26
Also published as: KR20060007194A; CN101010345A; KR100597418B1; RU2007101279A

Abstract

Disclosed are a solvent for polymerization and a method for preparing polymers using the same. The solvent is less harmful to the human body, causes a resultant polymer to be present always in a liquid phase, and is not evaporated during polymerization and thus is present in a polymer in such a manner that the whole polymer may serve as active component, resulting in reduction of the polymer production cost.

Description

SOLVENT FOR POLYMERIZATION AND METHOD FOR PREPARING POLYMER USING THE SAME

Technical Field

[1] The present invention relates to a solvent for polymerization and a method for preparing polymers using the same. More particularly, the present invention relates to a solvent for polymerization, which is less harmful to the human body, causes a resultant polymer to be present always in a liquid phase, and is not evaporated during poly¬ merization and thus is present in a polymer in such a manner that the whole polymer may serve as active component capable of further proceeding of a reaction, resulting in reduction of the polymer production cost, and to a method for preparing polymer using the same solvent. Background Art

[2] As generally known in the art, polymerization processes are classified into bulk polymerization, solution polymerization, emulsion polymerization and suspension polymerization processes. Among those processes, a solution polymerization process using a solvent or dispersion medium is controlled with ease in terms of poly¬ merization heat contrary to a bulk polymerization process. However, solution poly¬ merization is problematic in that it is necessary to use organic solvents that are harmful to the human body and flammable in a closed space (for example, benzene, toluene, xylene, DMF, THF, acetone, etc.) for carrying out polymerization. Therefore, it is a conventional trend to prepare polymers by using emulsion or suspension poly¬ merization processes, considering the problems occurring in the polymers obtained by solution polymerization and effects on the environment.

[3] However, polymers obtained by emulsion polymerization or suspension poly¬ merization processes are those of water-dispersible type. When such water-dispersible polymers are used as surface coating agents, they show poor interfacial adhesion or smoothness compared to polymers obtained by solution polymerization processes due to the difference in properties between water used as dispersion medium and a coating interface.

[4] Therefore, it is necessary to provide a novel solvent, which is less harmful to the human body compared to conventional organic solvents, in order to prepare polymers by solution polymerization processes.

[5] Meanwhile, although solvents used generally in the art for carrying out poly¬ merization can dissolve polymers and serve to control the polymerization heat during polymerization, they are exhaustive components, which are evaporated and exhausted ultimately. Additionally, because such conventional solvents have a low boiling point, they cannot cause a resultant polymer to be present always in a liquid phase at room temperature. Therefore, when a liquid polymer is desired (for example, when concrete structures are repaired), there is a problem in that it is necessary to perform an additional step of separately liquefying polymers. Moreover, such conventional solvents are exhaustive components, resulting in an increase in polymer production cost compared to polymerization processes using active solvents. Disclosure of Invention Technical Problem

[6] Accordingly, the present invention has been made to solve the above-mentioned problems occurring in the prior art. We have studied intensively to develop a novel solvent for polymerization, which is less harmful to the human body, causes a resultant polymer to be present always in a liquid phase, and is not evaporated during poly¬ merization and thus is present in a polymer in such a manner that the whole polymer may serve as active component capable of further proceeding of a reaction, resulting in reduction of the polymer production cost. Finally, we have found that when silane compounds such as tetraethoxysilane and tetramethoxysilane are used as solvent for polymerization, they can satisfy the above requirements. The present invention is based on this finding.

[7] Therefore, an object of the present invention is to provide a solvent for poly¬ merization, which is less harmful to the human body compared to organic solvents that have been conventionally used for solution polymerization, causes a resultant polymer to be present always in a liquid phase, and is not evaporated during polymerization and thus is present in a polymer in such a manner that the whole polymer may serve as active component capable of further proceeding of a reaction, resulting in reduction of the polymer production cost.

[8] Another object of the present invention is to provide a method for preparing polymers by using the same solvent. Technical Solution

[9] In order to accomplish this object, there is provided a method for preparing polymers characterized by using a silane compound represented by the following formula 1 as solvent.

[10] [Formula 1]

[H] R₄-

[12] wherein R , R , R and R are the same or different and each represents a methoxy or ethoxy group.

[13] Hereinafter, the present invention will be explained in more detail. [14] The solvent for polymerization according to the present invention is a silane compound represented by the following formula 1. Preferably, the compound represented by formula 1 is tetramethoxy silane (also referred to as "TMOS" hereinafter), tetraethoxy silane (also referred to as "TEOS" hereinafter) or a mixture thereof.

[15] [Formula 1] [16]

R₄-S

R₃

[17] wherein R , R , R and R are the same or different and each represents a methoxy

1 2 3 4 or ethoxy group.

[18] The silane compound, which is an inorganic substance, is less harmful to the human body compared to organic solvents that have been conventionally used for polymerization and has excellent dissolution capability, and thus is suitable for a solvent for polymerization.

[19] Additionally, because the silane compound has a high boiling point, it is hardly evaporated at room temperature, and thus causes a resultant polymer to be present always in a liquid phase. Therefore, a polymer formed by using the silane compound as solvent may be applied in a wide range of adhesives, paints, sealants, etc., with no need of additional liquefying treatment.

[20] Further, because the silane compound has methoxy groups or ethoxy group in its molecule, it reacts with functional groups such as hydroxy groups, amine groups, carboxyl groups, etc., with ease. Therefore, when monomers having such functional groups are used in a polymerization process, a polymer having methoxy groups or ethoxy groups derived from the solvent can be obtained, and thus the solvent can serve as active component while it is not evaporated. [21] Particularly, as shown in the following reaction scheme 1, copolymerization of t- butyl acrylate (I), methyl methacrylate (II) and hydroxyethyl acrylate (III) using TEOS as solvent and azobisisobutyronitrile (AIBN) as polymerization initiator results in the formation of a polymer through bonding of monomers having double bonds. At the same time, TEOS reacts with hydroxy functional groups present in hydroxyethyl acrylate (HI). Therefore, the solvent component can be present in the finally formed polymer (IV), and thus can serve as active component.

[22] [23] [24] [25] [26] [27] [28] [29] [Reaction Scheme 1] [30]

CH₃

H₂C=CH H₉C=C H^C=QH

AIBM

C = O C = O C=O

TEQS 0 O 0

H₃C — C — CH₃ C H₃ CH₂

CH_a CH₂O H

0) (H) (ED)

OC H₂CH₃

[31] [32] Meanwhile, a polymer obtained by using the solvent according to the present invention has ethoxy or methoxy groups present therein due to the solvent serving as active component. Therefore, when an acid or alkali catalyst is added to the finally formed polymer, the ethoxy or methoxy groups present in the polymer liberate ethanol or methanol to cause fast curing, resulting in the production of cured organic/inorganic polymer. Accordingly, the polymer obtained by using the solvent according to the present invention may be used in a wide range of applications including repairing of concrete structures based on this mechanism.

[33] More particularly, when the polymer obtained by using the solvent according to the present invention is applied on concrete surfaces for the purpose of repairing of concrete structures, the polymer present in a solution state not only exists on the concrete surface but also infiltrates into the concrete structures with ease. As a result, solidification of the polymer proceeds on the cracked surfaces of the concrete structures due to the effect of calcium hydroxide present in the concrete, resulting in sealing of the cracks and repairing of the structures. On the other hand, the polymer may be present in a solution state at the part that is not in contact with the concrete and may fill up the voids. When a newly cracked portion appears, the polymer present in the voids moves to the newly cracked portion, followed by solidification of the polymer and sealing of the cracked portion. Therefore, the above-mentioned mechanism may be applied to various fields including repairing of concrete structures.

[34] According to the present invention, the solvent may be used in an amount of between 5 wt% and 98 wt% based on the total weight of a composition to be polymerized. In other words, the solvent according to the present invention may be used in an adequate amount within the above range so that a polymer having a desired viscosity can be obtained depending on particular uses of the polymer.

[35] In polymerization processes using the solvent according to the present invention, there is no particular limitation in monomers to be polymerized as long as the monomers have double bonds in their molecules. However, it is preferable to use at least one monomer selected from the group consisting of styrene, methyl methacrylate, methyl acrylate, ethyl acrylate, butyl acrylate, acrylic acid, methacrylic acid, acryl amide, 2-ethylhexyl acrylate, 2-hydroxyethyl methacrylate, N-butyl acrylate, t-butyl acrylate and vinyl acetate.

[36]

[37]

Advantageous Effects

[38] As described above, when the silane compound represented by formula 1 is used for polymerization according to the present invention, it is possible to obtain polymers that have variable viscosity values depending on amounts of the solvent and are present always in a liquid phase. Therefore, it is possible to provide polymers useful for various applications including adhesives, paints, sealants, etc., according to the present invention.

[39] Additionally, when the silane compound is used for polymerization according to the present invention, the solvent is not evaporated but is present in the resultant polymer as active component. Therefore, it is possible to reduce the production cost of polymers based on the above mechanism.

[40] Further, the polymer formed by using the solvent according to the present invention reacts with an acid or alkali catalyst so that it is solidified. Therefore, when the polymer obtained according to the present invention is applied for repairing concrete structures, it is possible to achieve desired effects (for example, repairing of cracks) based on the above mechanism. Best Mode for Carrying Out the Invention

[41] Reference will now be made in detail to the preferred embodiments of the present invention. It is to be understood that the following examples are illustrative only and the present invention is not limited thereto.

[42] Example 1

[43] To a 5-ton reactor, 800 kg of TEOS and 8 kg of AIBN were introduced and purged with nitrogen gas. Then, 868 kg of methyl methacrylate, 300 kg of butyl acrylate, 32 kg of hydroxyethyl methacrylate and 20 kg of dodecyl mercaptan were added to a dropping funnel, followed by mixing, to provide a mixed solution of monomers.

[44] The reactor was heated to an inside temperature of 80°C, while being agitated at

80-120 rpm, and then the mixed solution of monomers contained in the funnel was added by drops into the reactor over a period of 5 hours. At this time, heat emission in the reactor was controlled carefully so that the inside temperature of the reactor did not exceed 90°C.

[45] 5 hours after the addition of mixed monomers, 2 kg of AIBN was further added and the resultant mixture was reacted for an additional 2 hours.

[46] Finally, a polymer having a final viscosity of 450 cps was obtained, wherein conversion of the reactants into polymer was 99.7%.

[47]

Mode for the Invention

[48] Example 2

[49]

[50] Example 1 was repeated to provide a polymer, except that the reactants described in the following Table 1 were used. [51] [52] Table 1

[53] [54] Finally, a polymer having a final viscosity of 750 cps was obtained, wherein conversion of the reactants into polymer was 99.8%.

[55] Example 3 [56] Example 1 was repeated to provide a polymer, except that the reactants described in the following Table 2 were used.

[57] Table 2

[58] [59] Finally, a polymer having a final viscosity of 850 cps was obtained, wherein conversion of the reactants into polymer was 99.6%.

[60] Example 4 [61] Example 1 was repeated to provide a polymer, except that the reactants described in the following Table 3 were used.

[62] [63] Table 3

[64]

[65] Finally, a polymer having a final viscosity of 750 cps was obtained, wherein conversion of the reactants into polymer was 99.8%.

[66] [67] Example 5 [68] Example 1 was repeated to provide a polymer, except that the reactants described in the following Table 4 were used.

[69] [70] Table 4

[71] [72] [73] Finally, a polymer having a final viscosity of 95 cps was obtained, wherein conversion of the reactants into polymer was 99.4%.

[74] Experimental Example [75] 0.6 kg of the polymer obtained from Example 5 was applied on a specimen having an area of 1 m² and a concrete strength of 400 kg/cm². After the application, it was shown that the polymer infiltrated into the specimen to a depth of 8 mm or more. Ad¬ ditionally, the concrete specimen was dipped into the polymer, left at room temperature for 48 hours, and then stored in a water tank with a depth of 2 m for 7 days. Next, the waterproof property of the specimen was tested. It was shown that the specimen did not accumulate water.

[76] As can be seen from the above Examples 1 to 5, when the solvent according to the present invention is used for polymerization, it is possible to obtain polymers having various viscosity values. Additionally, as can be seen from the above Experimental Example, because the polymer formed by using the solvent according to the present invention is present in a liquid phase, it can be applied to various uses directly with no need for a separate liquefying step so as to achieve desired effects.

[77] Reference Example

[78] To 100 kg of the polymer obtained from Example 1, 20% aqueous solution of a phosphate salt was added in an amount of 2 g. Then, the resultant mixture was stirred for 5 hours and left at room temperature for 48 hours. After the mixture was stored for 24 hours, it began to be solidified. Finally, after the lapse of 48 hours, a solid polymer having a final tensile strength of 316 kg/cm , elongation of 160% and a surface hardness of 4H or more as measured by pencil hardness was obtained.

[79] As can be seen from the above Reference Example, the polymer formed by using the solvent according to the present invention does not cause evaporation of the solvent. Moreover, because the solvent is present in the polymer as active component, addition of an acid or base to the resultant polymer results in further proceeding of a reaction, followed by the formation of a solid polymer.

[80] Although a preferred embodiment of the present invention has been described for il¬ lustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.

[81]

Claims

[ 1 ] L A method for preparing a polymer by solution polymerization of monomers for forming the polymer, characterized by using a silane compound represented by the following formula 1 as solvent: [Formula 1]

R₁ R₄-S

wherein R 1 , R2 , R 3 and R 4 are the same or different and each rep ^Vresents a methoxy or ethoxy group. [2] The method as claimed in claim 1, wherein the solvent is tetramethoxysilane

(TMOS), tetraethoxysilane (TEOS) or a mixture thereof. [3] The method as claimed in claim 1, wherein the silane compound as solvent is used in an amount of between 5 wt% and 98 wt% based on the total weight of a composition to be polymerized. [4] The method as claimed in claim 1, wherein the monomer is a monomer containing a double bond in its molecule. [5] The method as claimed in claim 4, wherein the monomer containing a double bond in its molecule is at least one selected from the group consisting of styrene, methyl methacrylate, methyl acrylate, ethyl acrylate, butyl acrylate, acrylic acid, methacrylic acid, acryl amide, 2-ethylhexyl acrylate, 2-hydroxyethyl methacrylate, N-butyl acrylate, t-butyl acrylate and vinyl acetate. [6] A polymer obtained by the method as claimed in any one of claims 1 to 5, which is present in a liquid phase.