KR20030088632A - Preparation of polyester/layered clay nanocomposites - Google Patents

Abstract

PURPOSE: Provided is a method for producing an eco-friendly polyester nano-composite for a high-rigidity plastic material, which has excellent workability, molding processability, and shape stability. CONSTITUTION: The method comprises the steps of melting and mixing a demineralized and layered clay mineral and a polyester resin as a matrix resin, together with 1-10 wt% of a modified polyester copolymer as a compatibilizing agent based on the total weight of the composite, in a twin extruder to peel and disperse the mineral in the matrix in a maximum degree, and then carrying out a solid phase polymerization. The layered clay mineral particles are peeled in a solid-phase polymerized resin to disperse the particles in the resin in nano-scale.

Description

Preparation method of polyester nanocomposite containing layered clay minerals {Preparation of polyester / layered clay nanocomposites}

The present invention uses a copolymerized modified polyester resin containing a small amount of inorganic particles in the form of chemically organically treated platelet and hydrophilic groups and ionic groups as a commercialization material, or in a predetermined ratio with a polyester resin, which is a matrix resin, in an extruder. The present invention relates to a method for producing a polyester-based nanocomposite obtained by uniformly dispersing and controlling an inorganic particle and then peeling the inorganic particle into a resin at a nano level.

Particularly, in the present invention, montmorillonite, a layered clay mineral, is compatible with a polyester resin, and a small amount of inorganic particles (Bis (2-hydroxyethyl) tallow quaternary) in the form of a plate is chemically treated for peeling effect in the polyester resin. ammonium chloride) and ionomer resins containing ionic and hydrophilic groups can be used in the melt mixing step to increase the compatibility between resin and inorganic particles. It is related with the method of manufacturing this excellent polyester resin composition.

Conventional high-performance resin moldings are mainly made of polyamide-based, polyolefin-based or other expensive special resins with excellent impact strength and heat resistance as matrix resins, and most resins alone have weak physical properties when used as molding materials. In order to mix and to obtain the required sufficient physical properties, mixing of a large amount of inorganic additives is essential, but in this case, there is a problem that it is difficult to uniformly mix the matrix resin and accompanied by a decrease in processability. At present, the polyester resin has a specific molecular weight of 0.6dl / g, which is a general molecular weight for fibers and films, but the polyester resin for tire cords, various containers, and resins for microwave ovens has a high molecular weight, intrinsic viscosity of 0.7dl / g or more. Resin is used.

In general, high molecular weight polyester resins having an intrinsic viscosity of 0.7 dl / g or more are uneconomical when produced by melt polymerization, and side reactions due to prolonged reactions result in deterioration of physical properties. have. However, in the case of ordinary polyester, even in the case of solid state polymerization, moldability is poor.

Therefore, the present invention has developed a method for producing a polyester composite resin having excellent moldability and excellent gas barrier properties by a relatively simple and economical method.

In Japanese Patent Laid-Open Publication No. 3-62846, proper physical properties for use as engineering plastics are insufficient, and in the polymerization method, a composite resin is swelled when an organically treated layered clay mineral is mixed with a liquid monomer. Therefore, the production of the composite resin is very difficult due to the line blocking phenomenon in the transfer process of the polymerization process.

Conventional polyester resins are used as fibers, films, containers, sheets, etc. as general-purpose applications, but they are used to produce composite resins for high performance resin compositions and applications having excellent gas barrier properties.

In addition, the existing engineering plastics use a large amount of minerals, glass fibers, and carbon fibers as reinforcing materials during manufacturing, which makes it difficult to recycle, causing environmental problems. I would like to present.

SUMMARY OF THE INVENTION An object of the present invention is a polyester resin composite material having excellent physical properties by melt-mixing a plate-like inorganic additive chemically treated with a polyester resin, which is a matrix resin, or by solid-phase polymerizing it again to peel the plate-like clay mineral into the resin at a nano level. It is to provide a method of manufacturing.

In using polyester resin as a high-performance molding material, the manufacturing method introduces the concept of microstructured particles at the molecular level, rather than the existing method of adding large particles, and provides a method for producing a resin composite material using a small amount of additives and recycling. .

As a reinforcing material of the concept of improving physical properties in resin, minerals, glass fibers and carbon fibers of spherical particles have been used. However, they can increase the mechanical properties required in the manufacturing process should be about 10 to 50wt%, and the environmental problems are increasing because it is almost impossible to recycle after use.

1 is a graph showing the physical properties of the resin composite material according to the layered clay mineral content.

2 is an X-ray diagram showing the effect of peeling dispersion of layered clay minerals in a resin composite material.

3 is a transmission electron micrograph showing the peeling dispersion effect of the layered clay mineral in the resin composite material.

4 is a graph showing the gas barrier effect of layered clay minerals in a resin composite material.

The present invention relates to a method for producing a polyester-based composite resin, and more particularly, a polyester resin copolymerized with a polyester resin (IV = 0.6) may be used, and a small amount of clay in the form of a chemically organically treated plate may be used. Minerals are melt-mixed in the extruder at a suitable ratio under appropriate conditions and then prepared to the extreme viscosity (IV) of about 0.5 to 0.6 dl / g, or solid-phase polymerized to give the ultimate viscosity (IV) of about 0.8 to 1.0 dl / g. The present invention provides a method of preparing a composite resin having excellent mechanical and thermal properties by exfoliating nanoclay minerals on the resin.

The present invention is a case of producing a resin composite by peeling and dispersing a layered clay mineral having a silicate laminated structure in a sheet form (thickness of 1 nm, length of 1 μm) in a polyester resin matrix, respectively. Physical properties such as elastic modulus, heat deflection temperature, and gas permeability are greatly improved (see Table 1).

Figure 1 shows the increase in modulus when prepared in the nanocomposite by increasing the content of the organic layered clay minerals in polyethylene terephthalate matrix resin. Figure 1 (a) is a graph showing the increase in tensile elasticity with increasing clay content, Figure 1 (b) is a graph showing the increase in bending modulus with increasing clay content.

However, very strong electrostatic attraction acts between the silicate plates, which are layered clay minerals, and it is not easy for organic polymers, which are matrices, to be inserted into these laminated structures to exfoliate and uniformly disperse the plate structures. Therefore, a layered clay mineral was organically treated to increase the affinity between the polyester resin and the silicate layer, and the layering layer of the polyester resin and the organic treatment was used as a compatibilizer to maximize the dispersing effect by further increasing its peeling effect. It is also possible to use modified copolyesters having both hydrophilic and ionic groups which have affinity for both clay minerals.

The method of manufacturing the nanocomposite, which is a resin / layered clay mineral, includes a solution method, a polymerization method, a melt mixing method, and the like, but an effective method needs to be selected according to the matrix resin type, application field, manufacturing cost, and the like. However, the solution method is a matter of selecting a suitable solvent and preparing a sample, and the polymerization method also has a poor transfer rate in a valve or a curved line in the transfer process when the layered clay mineral becomes more than 1wt% in the swollen state with the monomer in the manufacturing process. It is very difficult to produce composite resins such as clogging and maintaining reaction equilibrium. Melt mixing method can use a conventional injection or extrusion molding machine, it is possible to manufacture a nanocomposite without changing the molding conditions. In the present invention, this method is applied. A polyester-based nanocomposite prepared in this manner was used to prepare a specimen using a general injection molding machine to obtain various required physical properties.

The present invention describes in detail a method for producing a resin nanocomposite for use in resin moldings and high-performance gas barrier containers. According to the present invention, basic matrix resin polymerization was carried out by adjusting additives such as catalysts and stabilizers at a constant concentration, using various monomers of diol system such as high purity terephthalic acid (PTA), ethylene glycol (EG) and 1.4 butanediol as raw materials. In the above, without using an inorganic additive such as a matting agent (TiO ₂ ), a highly transparent polyester base resin having an intrinsic viscosity (IV) of about 0.6 dl / g was dried to a moisture content of less than about 50 ppm. The layered silicate clay mineral, which is a matrix resin reinforcing material, was organically treated with montmorillonite having a thickness of about 2 to 13 µm in length and thousands of nanometers in thickness. That is, a layered silicate inorganic nano material having a cation exchange capacity (CEC) of 90 to 125 meq / 100 g, montmorillonite of 50 to 75%, and a CEC component of 25 to 40% was used. In order to disperse the layered clay mineral particles in the form of uniform peeling on the matrix resin, as a compatibilizer, a copolyester resin having affinity for both of the above materials, namely, the layered nano inorganic particles and the matrix resin, was synthesized. Used.

Copolyester resins are monomers of high purity terephthalate (PTA), ethylene glycol (EG) and polyethylene glycol, which have a molecular weight of 600 to 6000, and ionic groups of sodium sulfonate in the range of 1 to 7 mole%. Modified copolyesters having ionomers were prepared using the monomers of the intrinsic viscosity (IV) at a level of 0.70 dl / g and used as a compatibilizer. It contains both hydrophilic and ionic groups in the molecular structure, facilitating intercalation of organically treated layered clay minerals, increasing the exfoliation effect at the molecular level, and translating both materials by transesterification with polyester resins, matrix resins. Acts to impart affinity at the same time. Hereinafter, the present invention will be described in detail by way of examples and comparative examples according to a method of manufacturing a polyester-based nanocomposite.

Example 1

The composition and physical properties of this example are shown in Table 1. 95wt% of polyester resin with intrinsic viscosity of 0.64dl / g and water content of 50ppm or less, and layered silicate minerals of about 2 ~ 13㎛ in length and layer thickness of thousands of nanometers. 5 wt% resin reinforcement was melt-mixed into 50 ~ 75% of constituents and 25 ~ 40% of constituents of organicized CEC) to prepare nanocomposite in pellet form, and the prepared resin ranged from 210 ~ 240 ℃. Solid phase polymerization was performed at about 10 to 19 hours to prepare a polyester nanocomposite composite having a final intrinsic viscosity (IV) of 0.8 dl / g. Various specimens were prepared using the nanocomposite resin and the physical properties and the degree of uniform dispersion of the inorganic clay mineral in the resin were measured by XRD and TEM (transmission scanning microscope). Reference)

Figure 2 shows the degree of dispersion by X-ray irradiation of the degree of peeling dispersion of the layered organic mineralized clay mineral in the nanocomposite. 2 shows Example 3, Example 2, Example 1 and layered clay minerals from above.

In FIG. 3, the degree of peeling and dispersion was visually confirmed through a transmission electron microscope in order to confirm the degree of peeling and dispersion of the organic-treated nano inorganic additive in the nanocomposite. Fig. 3 (a) shows Example 1, Fig. 3 (b) shows Example 2, and Fig. 3 (c) shows Example 3, which are enlarged 100,000 times.

Example 2

The composition and physical properties of this example are shown in Table 1. Modified copoly with an intrinsic viscosity of 0.7 dl / g and a moisture content of 50 ppm or less for the purpose of maximizing the dispersing effect and improving the physical properties by completely peeling off the plate-shaped laminated inorganic particles to the polyester resin as the matrix resin using the reinforcing material as in Example 1. Ester was used and the same procedure as in Example 1 was repeated.

The modified copolyester is an ionomer having both hydrophilic and ionic groups in the molecule. The hydrophilic group in the molecule is a polyol system having a molecular weight ranging from 600 to 6000. It is about 10% in the entire molecule and the sodium sulfonate ion group is 1 to 7 mole%. Applied.

Before using the layered clay mineral, which is an inorganic particle additive, it was dried to less than about 100 ppm of moisture to remove the large particles, and the matrix resin used before the melt mixing and the resin used as the compatibilizer were controlled to maintain a constant moisture content.

Melt extruder for manufacturing nanocomposite material has less kneading effect when L / D is lower than 25 or screw diameter is 20mm, so that it is difficult to uniformly disperse in extruder, so L / D = 36, screw diameter is about 40mm The twin-screw extruder with the standard of was used. The exfoliation effect of the layered clay mineral and the transesterification reaction of the polyester resin, which is a matrix resin, and the modified copolyester having a hydrophilic group and an ionic group, which are compatibilizers, ranged from 245 to 255 ° C. When the screw speed is in the range of 100 ~ 150rpm is effective. Prior to melt mixing, the matrix resin, compatibilizer modified resin, and organic layered clay minerals are weighed in advance and mixed uniformly in a batch form in a batch form before being melt mixed and extruded after extruded (resin Composite) was passed through the cooling water to solidify and cut to a certain size to prepare a nanocomposite resin.

In addition, the final polyester nanocomposite resin was obtained through a solid-phase polymerization process in order to increase the molecular weight and increase the peeling effect to improve the final physical properties of the composite resin. Solid phase polymerization process is possible in batch or continuous process, and then, after precrystallization, crystallization and drying by temperature and time in a single process, the polyester nano resin composite is manufactured by solid phase polymerization in the range of 200 ~ 240 ℃ and 10 ~ 19 hours. It was.

Example 3

The same procedure as in Example 1 was repeated except that the matrix resin was used as copolyester having a hydrophilic group and an ionic group in place of the polyester resin.

Comparative Example 1

Solid phase polymerization was carried out with polyester resin alone, which is a matrix resin, to obtain physical properties in the same manner as in Example 1.

Comparative Example 2

The same procedure was repeated except that the solid phase polymerization process was omitted in the same manner as in Example 1.

Comparative Example 3

The same procedure as in Comparative Example 2 was repeated in the same manner as in Example 3.

[Comparative Example 4]

The same procedure as in Comparative Example 2 was repeated in the same manner as in Example 2.

<Table 1> Composition and Properties Table

Item Example Example Example Comparative example Comparative example Comparative example Comparative example number One 2 3 One 2 3 4 Furtherance Layered clay minerals Montmorillonite Montmorillonite Montmorillonite Montmorillonite Montmorillonite Montmorillonite Organic Treatment Clay Mineral Weight (wt%) 5 5 5 5 5 5 Compatibilizer Resin Weight (wt%) 10 95 95 10 Matrix resin weight (wt%) 95 85 100 95 85 Solid state polymerization practice practice practice practice Not carried Not carried Not carried Properties Tensile Strength (MPa) 61.7 60.0 68.8 55.5 Tensile Modulus (MPa) 2599.0 3281.0 3231.0 1970.1 3445.5 3234.8 3424.8 Flexural Modulus (MPa) 3787.0 4399.0 4515.3 2998.1 2936.0 2990.0 3012.35 Heat Deflection Temperature (℃) 111.0 114.2 107.1 75.6 85.4 102.5 106.4

Table 1 is an organic treatment of the layered clay mineral to polyethylene terephthalate resin, which is a matrix resin, divided into Comparative Examples and Examples according to the use of compatibilizers, the content and content of the compatibilizer, the solid-state polymerization, and nothing. Indicated.

In order to solve the above-mentioned problems, the present invention can be used as a polyester composite resin which can be produced with high productivity and low cost, as a resin having excellent gas barrier properties or a high-strength plastic material (see Fig. 4).

FIG. 4 shows that in the case of a nanocomposite prepared using a layered inorganic nano additive, gas permeability is suppressed as a gas passage path is blocked due to peeling dispersion of plate-shaped inorganic particles in the composite. Here, in order to confirm this indirectly, the result of testing the absorbency of the solvent in acetone solvent was shown and the effect was proved. (Example 1 and Comparative Example 1)

As described above, the present invention has an effect of economically manufacturing polyester-based nanocomposites for high-strength plastics with excellent workability and molding processability, and does not use inorganic additives such as glass fibers of Danson. By using a very small amount of the plate-shaped fine particles in size, it is possible to recycle, and the crystallization is fast during molding, it is possible to produce an environmentally friendly composite material as a composite resin material excellent in shape stability.

Claims (3)

In order to maximize the dispersing effect by peeling the layered clay mineral into polyester resin, which is a matrix resin, the modified copolyester having hydrophilic and ionic groups in the molecule is used in a solid phase polymerization using 1 to 10wt% of the total composite material. Method for producing polyester-based nanocomposites. When manufacturing a composite resin, the matrix resin is melt mixed using a layered nano inorganic mineral particle and a solid state polymerized high viscosity resin (viscosity IV = 0.8 to 10 dl / g) or low viscosity resin (viscosity IV = 0.5 to 0.7 dl / g). After melt-mixing the nano-inorganic particles, the solid-phase polymerization of the inorganic particles in the range of 210 ~ 230 ℃ for more than about 10 ~ 19 hours to uniform dispersion of the inorganic particles and physical strength and inorganic particles of the high viscosity composite resin (viscosity IV = 0.8 ~ 1.0dl / g) Dispersing and peeling the resin in the resin to increase the heat deformation temperature and gas barrier properties. The resin composite material according to claim 1 or 2, wherein the matrix resin is used as polyethylene terephthalate, polybutylene terephthalate, polyethylene terephthalate-co-isophthalate, polyethylene naphthalate, or polytrimethylene terephthalate, respectively. Manufacturing method.