KR100971312B1 - Synthetic method of polyvinylchloride nanocomposite via in situ miniemulsion polymerization - Google Patents

Abstract

The present invention relates to a method for synthesizing polyvinyl chloride nanocomposites using in situ mini emulsion polymerization, and more specifically, a) nanoparticles of any one of clay or calcium carbonate, co-stabilizer and initiator And, mixing the vinyl chloride monomer, aging to prepare a mixed solution; b) stirring the mixed solution to disperse the nanoparticles into a thin plate; c) emulsifying by adding a surfactant to the dispersed mixed solution; And d) homogenizing the emulsified mixed solution with a high-strength homogenizer, and mini emulsion polymerization.

According to the present invention, a polyvinyl chloride nanocomposite in which nanoparticles are uniformly dispersed and bonded to a vinyl chloride monomer can be synthesized.

Polyvinyl chloride, nanocomposite, clay, in situ, mini emulsion polymerization

Description

Synthetic method of polyvinylchloride nanocomposite via in situ miniemulsion polymerization}

The present invention relates to a method for synthesizing a polyvinyl chloride nanocomposite, and more particularly to a method for synthesizing a polyvinyl chloride nanocomposite exhibiting excellent physical properties in plasticity, viscosity and fluidity by dispersing and bonding nanoparticles to polyvinyl chloride. It is about.

Conventional Solvin and Solvay's joint venture have synthesized an innovative polyvinyl chloride nanocomposite (NanoVin) that combines clay nanoparticles with polyvinyl chloride (PVC).

The polyvinyl chloride nanocomposites have differentiating characteristics in plasticity, viscosity, and flow, and are materials that sense environmental changes and react accordingly due to these rheological properties.

In particular, it exhibits non-dripping and shear-thinning properties, making it suitable for use as a product for polyvinyl chloride (PVC) paste applications. Here, the oil film reduction characteristic means that the viscosity of the material decreases when shear stress is applied, and the viscosity value increases when the shear stress decreases.

That is, the polyvinyl chloride nanocomposite can be said to be a material having a high commercial value that can be applied to various industrial fields from a thick coat such as artificial feather to a field such as a car body of the automobile industry by the above characteristics.

To date, however, little is known about the polyvinyl chloride nanocomposites other than Solvay's report.

Hereinafter, referring to the surface particles of the polyvinyl chloride nanocomposite prepared by the conventional method of synthesizing the polyvinyl chloride nanocomposite with reference to FIG. 1, it can be seen that the conventional polyvinylchloride nanocomposite was synthesized using seed emulsion polymerization. Can be.

That is, the seed emulsion polymerization is a natural clay that exhibits hydrophilicity, or clay whose surface is organically modified to exhibit hydrophilicity, split into thin plates in water, delaminates, and the clay dispersed in thin plates is seed particles in the polymerization process. It was composed of two steps that are synthesized by being absorbed or adsorbed on the surface of the.

However, small seed grains grown in surfactant micelles are pure polyvinyl chloride, and in the case of synthesizing polyvinyl chloride nanocomposites using the synthetic method by conventional seed emulsion polymerization, the clay plates are formed in the polyvinyl chloride matrix. There was a problem that it is unevenly distributed.

In addition, there is a problem that adversely affects the improvement of mechanical and rheological properties of the polyvinyl chloride nanocomposites synthesized due to the above problems.

The present invention has been made to solve the above problems, and provides a method for synthesizing polyvinyl chloride nanocomposites using in situ miniemulsion polymerization to disperse and bind nanoparticles to vinyl chloride monomer more simply and uniformly. There is a purpose.

Synthesis method of the polyvinyl chloride nanocomposite using the in situ mini-emulsion polymerization of the present invention for achieving the above object, a) nanoparticles of any one of clay or calcium carbonate, co-stabilizer and Preparing a mixed solution by mixing the initiator and the vinyl chloride monomer, and aging; b) stirring the mixed solution to disperse the nanoparticles into a thin plate; c) emulsifying by adding a surfactant to the dispersed mixed solution; And d) homogenizing the emulsified mixed solution with a high-strength homogenizer and mini emulsion polymerization.

In the step a), the mixed solution is preferably swelled by aging for 2 to 4 hours, by aging the mixed solution as described above b) nano-containing in the mixed solution in the dispersing step (S120) to be described later The particles can be delaminated by better dispersion in thin plates in the vinyl chloride monomer.

Here, the clay is preferably any one selected from the group consisting of montmorillonite, smectite and hectorite, more preferably montmorillonite is used. The montmorillonite has the advantage of being cheap and easy to obtain and easily changing the properties of the surface.

In addition, as the calcium carbonate, it is more preferable to use a surface treated to show hydrophobicity.

The nanoparticles serve to enhance mechanical properties in the polyvinyl chloride nanocomposite, and when the nanoparticles are used, mechanical properties such as tensile strength may be improved as compared to conventional polyvinyl chloride. In addition, in the case of the clay is easy to control the viscosity, mainly serves to increase the viscosity has the advantage of not having to use an additional viscosity modifier in a particular use, such as coating.

In addition, the co-stabilizer can be used for all hydrocarbon group of C7 or more, so long as the solubility in water, such as oil can be used, not only hydrocarbon group but also hydrocarbon group long hydrocarbon group such as cetyl alcohol (cetyl alcohol) It can be used as a tablet.

The co-stabilizer plays a role of stably maintaining the monomeric spherical droplets under the polymerization conditions in the polyvinyl chloride nanocomposite, and the mixed solution should have low solubility with water. It is preferable to use a co-stabilizer having a carbon number of C18 or less because it is present as a solid at room temperature and less compatible.

Therefore, more preferably, hexadecane having a melting point of about 18 ° is used.

In addition, the initiator is a hydrophobic polymerization initiator, azo compounds such as 2,2'-azobisisobutyronitrile (ABIN), azobisdimethylvaleronitrile (ABVN) or cumene hydroperoxide, t-butyl hydroperoxide , One or two or more selected from peroxides such as dicumyl peroxide, di-t-butyl peroxide, benzoyl peroxide and lauroin peroxide may be used, and more preferably 2,2'-azobisiso Butyronitrile and benzoyl peroxide can be used.

In addition, the mixed solution preferably contains 0.1 to 15 parts by weight of the nanoparticles, 0.5 to 5 parts by weight of the co-stabilizer and 0.01 to 1 parts by weight of the initiator with respect to 100 parts by weight of the vinyl chloride monomer.

In addition, the surfactant may use all of anionic, nonionic and cationic surfactants, and more preferably, sodium lauryl sulfate, which is effective and inexpensive, is used as the anionic surfactant.

In addition, in step b), the mixed solution is preferably stirred for 10 to 180 minutes at 100 to 20000 rpm, and in step c), the surfactant is dispersed at the mixed solution in a range of 1 to 60 at 100 to 20000 rpm. It is preferred to stir while adding slowly for minutes.

In steps b) and c), when the stirring speed of the mixed solution is higher than the numerical range, the stirring becomes difficult due to the increase in viscosity, and when the stirring speed is lower than the numerical range, dispersion is not performed well. There is a problem.

In addition, in step d), the mixed solution emulsified is preferably homogenized for 10 to 30 minutes at 5000 ~ 50000rpm, and mini emulsion polymerization for 2-6 hours at 54 ~ 80 ℃.

In the case of mini emulsion polymerization of the emulsified mixed solution, there is a problem in that the economic efficiency is lowered when the stirring condition is out of the numerical range. There is a problem that is not.

In addition, the mini emulsion polymerized mixed solution is preferably formed on the surface of the dispersed nanoparticles of 100 ~ 1000nm, when the size of the dispersed nanoparticles larger than 1000nm there is a problem that the mechanical stability of the nanocomposite is poor In case of less than 100 nm, the viscosity of the latex becomes very large.

Synthesis method of polyvinyl chloride nanocomposite using in situ mini emulsion polymerization of the present invention as described above,

First, it is possible to carry out the synthesis of the polyvinyl chloride nanocomposite more easily because it is made in an in situ manner in which all the reactions are carried out in one container without carrying out the synthesis.

Second, since the synthesized polyvinyl chloride nanocomposite is uniform crystal nucleation is formed, the nanoparticles are uniformly dispersed in the vinyl chloride monomer may exhibit excellent mechanical and rheological properties.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, terms or words used in the specification and claims should not be construed as having a conventional or dictionary meaning, and the inventors should properly explain the concept of terms in order to best explain their own invention. Based on the principle that can be defined, it should be interpreted as meaning and concept corresponding to the technical idea of the present invention.

Therefore, the embodiments described in the specification and the drawings shown in the drawings are only the most preferred embodiments of the present invention and do not represent all of the technical idea of the present invention, various equivalents that may be substituted for them at the time of the present application It should be understood that there may be water and variations.

Hereinafter, a method of synthesizing a polyvinyl chloride nanocomposite using in situ mini emulsion polymerization according to an embodiment of the present invention will be described with reference to FIGS. 2 to 5.

2 is a block flow diagram illustrating a method of synthesizing a polyvinyl chloride nanocomposite using in situ mini emulsion polymerization according to an embodiment of the present invention, and FIG. 3 is a synthetic method of the polyvinyl chloride nanocomposite of FIG. It is a photograph of the polyvinyl chloride nanocomposite, FIG. 4 is an XRD graph of the polyvinyl chloride nanocomposite shown in FIG. 3, and FIG. 5 is a TEM photograph of the polyvinyl chloride nanocomposite shown in FIG.

Referring to Figure 2, the synthesis method of polyvinyl chloride nanocomposite using in situ mini emulsion polymerization according to an embodiment of the present invention is a) mixed solution preparation step (S110), b) dispersion step (S120), c) Emulsifying step (S130) and d) mini emulsion polymerization step (S140).

First, a nanoparticle, a co-stabilizer and an initiator are contained in a reactor, while slowly injecting a vinyl chloride monomer, nanoparticles are dispersed in a vinyl chloride monomer to prepare a mixed solution (S110). In this case, the mixed solution is preferably matured for 2 to 4 hours to swell, and when the mixed solution is aged b) in the subsequent dispersion step (S120), the nanoparticles may be more easily dispersed in a thin plate.

In other words, when the mixed solution is prepared, the nanoparticles are dispersed in a thin plate by stirring with a mechanical stirrer (S120). This dispersing step is called delamination, and the nanoparticles in the mixed solution are dispersed in thin plate pieces in the vinyl chloride monomer.

Next, the surfactant is added and emulsified in the mixed solution dispersed (S130).

The surfactant is used as an emulsifier, prepared by containing a surfactant consisting of an aqueous solution of sodium lauryl sulfate (SLS) and pure water in another vessel prepared separately from the reactor containing the mixed solution, and the dispersed mixture The mixed solution is emulsified while slowly adding the surfactant to the reactor containing the solution.

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Subsequently, the polyvinyl chloride nanocomposite is synthesized by homogenizing the mixed solution emulsified using a high strength homogenizer and mini emulsion polymerization (S140).

Hereinafter, a process of synthesizing the polyvinyl chloride nanocomposite according to the synthesis method of the polyvinyl chloride nanocomposite using the in situ mini emulsion polymerization of the present invention will be described in more detail with reference to Example 1 below.

Example  One

An aqueous solution of 315 g of DI water and 2.7 g of sodium lauryl sulfate (SLS) was prepared as a surfactant in a 1 L first reactor, 5.4 g of Cloisite® 20A and hexadecane. A mixture of 2.7 ml, 0.06 g of 2,2'-azobisisobutyronitrile (ABIN) and 0.03 g of azobisdimethylvaleronitrile (ABVN) was added to the second reactor. The materials used and their contents are shown in Table 1 below.

After slowly injecting a vinyl chloride monomer into the second reactor containing the mixture, the mixture was aged at 250 rpm for 3 hours to prepare a mixed solution, followed by stirring the mixed solution at 1000 rpm for 10 minutes to form nanoparticles in the vinyl chloride monomer. The clay Cloisite®20A was dispersed in a thin plate.

Next, while slowly stirring the mixed solution dispersed in the second reactor at 500 rpm, the surfactant solution contained in the first reactor was slowly injected into the second reactor for 5 minutes to emulsify.

Subsequently, the homogenizer (Ultra-Turrax IKA®) of high strength allows the emulsified mixed solution to be stably mini emulsion polymerization. After homogenizing at 22000 rpm for 20 minutes using T25), the reactor temperature was raised to 58.5 degrees, and polyvinyl chloride monomer was polymerized for 4 hours to synthesize polyvinyl chloride nanocomposite (PVC-clay nanocomposite latex).

The photo of the polyvinyl chloride nanocomposite prepared in Example 1 is shown in Figure 3, through which it was confirmed that the polyvinyl chloride nanocomposites in which nano clay is dispersed uniformly.

In addition, as shown in FIG. 4, the Cloisite®20A of Example 1 through XRD showed a D ₀₀₁ peak of 3.3 ° at 2θ, corresponding to 26.5 nm, which is the spacing between the thin plates, while the polyvinyl chloride nanocomposite of It was confirmed that the peak disappeared.

This means that the nano clay was completely dispersed in the polyvinyl chloride nanocomposite, and FIG. 5 shows a TEM photograph of the polyvinyl chloride nanocomposite prepared by Example 1. FIG.

As mentioned above, although this invention was demonstrated by the limited embodiment and drawing, this invention is not limited by this, The person of ordinary skill in the art to which this invention belongs, Of course, various modifications and variations are possible within the scope of equivalent claims.

1 is a photograph of a polyvinyl chloride nanocomposite prepared by a method of synthesizing a conventional polyvinyl chloride nanocomposite,

2 is a block flow diagram illustrating a method for synthesizing a polyvinyl chloride nanocomposite using in situ mini emulsion polymerization according to an embodiment of the present invention.

3 is a photograph of a polyvinyl chloride nanocomposite synthesized by the method for synthesizing the polyvinyl chloride nanocomposite of FIG.

4 is an XRD graph of the polyvinyl chloride nanocomposite shown in FIG.

FIG. 5 is a TEM photograph of the polyvinyl chloride nanocomposite shown in FIG. 3.

Claims (7)

a) mixing a nanoparticle of any one of clay or calcium carbonate, a co-stabilizer, an initiator, and a vinyl chloride monomer, and aging to prepare a mixed solution; b) stirring the mixed solution to disperse the nanoparticles into a thin plate; c) emulsifying by adding a surfactant to the dispersed mixed solution; And d) a method of synthesizing the polyvinyl chloride nanocomposite using in situ mini emulsion polymerization, comprising homogenizing the emulsified mixed solution with a high strength homogenizer and mini emulsion polymerization. The method of claim 1, The clay is a synthetic method of polyvinyl chloride nanocomposite using in situ mini emulsion polymerization, characterized in that any one selected from the group consisting of montmorillonite, smectite and hectorite. The method of claim 1, The co-stabilizer is a method of synthesizing polyvinyl chloride nanocomposites using in situ mini emulsion polymerization, characterized in that hexadecane. The method of claim 1, In the step b), the mixed solution is a method of synthesizing polyvinyl chloride nanocomposite using in situ mini emulsion polymerization, characterized in that for 10 to 180 minutes stirring at 100 ~ 20000rpm. The method of claim 1, In the step c), a method of synthesizing the polyvinyl chloride nanocomposite using the in-situ mini emulsion polymerization, characterized in that the stirring is slowly added to the dispersed solution at 100 ~ 20000rpm for 1 to 60 minutes. The method of claim 1, In the step d), the mixed solution emulsified poly homogenized by in-situ mini emulsion polymerization, characterized in that homogenization for 10 to 30 minutes at 5000 ~ 50000rpm, mini emulsion polymerization for 2 to 6 hours at 54 ~ 80 ℃ Synthesis method of vinyl chloride nanocomposite. The method of claim 1, The mini emulsion polymerized mixed solution is a method of synthesizing polyvinyl chloride nanocomposite using in situ mini emulsion polymerization, characterized in that the nanoparticles are dispersed in 100 ~ 1000nm.

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