KR100874475B1 - Clay dispersed nanocomposite and its manufacturing method. - Google Patents

Abstract

A clay dispersed nanocomposite and a method for producing the same are provided. The clay dispersed nanocomposite according to the present invention includes a polymer resin comprising an ABS copolymer in a continuous phase and a PC in a dispersed phase; And clays surface-modified with quaternary ammonium containing aromatic functional groups, and have excellent dispersibility of clays in nanocomposites, and as a result, heat resistance and the like of the nanocomposites are improved.

Description

Clay-dispersed nano-composite and preparation method

The present invention relates to a clay dispersed nanocomposite and a method for manufacturing the same, and more particularly, to a nanocomposite having excellent dispersibility of clay in a nanocomposite, and improved heat resistance and the like.

Acrylonitrile-butadiene-styrene copolymer (hereinafter referred to as 'ABS') and polycarbonate (hereinafter referred to as 'PC') nanocomposites have excellent mechanical properties and heat resistance of PCs by blending ABS and PC, and excellent processability and economy of ABS. It is a kind of harmonized polymer composition. These polymer compositions have been researched in that many or more polymer materials can be mixed or compounded to maximize the advantages of each material and complement the disadvantages, and various polymer products are produced.

ABS / PC nanocomposites have been commercialized worldwide since they were first commercialized by Borg-Warner in 1970. PC is one of the five general-purpose engineering plastics, and is widely used in various fields because it is transparent, has excellent mechanical strength and impact strength, and has high heat resistance. However, PC has a high molding temperature and a relatively high melt viscosity, so that residual stress may exist in the molded article during injection molding. In addition, there is a disadvantage that the chemical resistance is weak and can be hydrolyzed by moisture. Accordingly, ABS / PC nanocomposites have been developed for the purpose of solving the disadvantages of the PC and simultaneously improving the mechanical properties and heat resistance of the general purpose ABS. However, conventional ABS / PC nanocomposites have a problem that the ratio of PC must be larger than that of ABS copolymer in order to obtain physical properties such as constant mechanical strength. That is, when the PC and the ABS copolymer which are heterogeneous materials are mixed, the one with a higher weight ratio becomes a continuous phase, and the one with the smaller weight ratio with respect to the continuous phase is dispersed, that is, a dispersed phase. Therefore, in the general ABS / PC nanocomposite, when PC is a continuous phase and ABS is a dispersed phase, the desired mechanical strength and heat resistance can be satisfied. Compared with the disadvantages of workability and high price, it is necessary to reduce the weight ratio of PC in ABS / PC nanocomposites.

In addition, there was a method of using an organic / inorganic composite material as a method of improving various physical properties by peeling and dispersing inorganic particles in a nano-scale to a polymer material such as a thermoplastic resin or a thermosetting resin. Since the inorganic particles are present in the aggregated state in the polymer, there is a problem of only increasing the strength of the composite material slightly. Among the nanocomposites using inorganic particles, there are clay dispersed nanocomposites. The clay dispersed nanocomposites cause peeling of the layered structure by infiltrating the nanocomposite between layers of clay minerals (clay) such as montmorillonite of silicate layered structure. , The nanoscale plate silicate can be peeled off and dispersed in the nanocomposite, thereby improving the physical properties of general purpose polymers having poor mechanical properties.

As a technology related to such clay-dispersed nanocomposites, a technique using clay such as montmorillonite for physical properties of ABS / PC nanocomposites is disclosed in Korean Patent Laid-Open Publication No. 10-2005-0114459. The technique is to modify the clay with a lipophilic organizing agent to improve the dispersibility by increasing the affinity of the clay for the nanocomposite, wherein the modification of the clay is substituted with methyl groups and hydrogenated tallow. Proceed with secondary ammonium salts. However, the modified clay may not be sufficiently peeled off from the nanocomposite of the modified clay. In particular, when the ABS is used as a continuous phase to increase workability, the modified clay is sufficiently peeled off and difficult to be dispersed in the nanocomposite.

Furthermore, if the clay is dispersed without being sufficiently peeled in the nanocomposite as in the prior art, the clay is agglomerated in the nanocomposite and has a high probability of being present at a high concentration in the local region. In this case, the clay to be dispersed throughout the nanocomposite to improve the performance of the nanocomposite may not produce a sufficient effect in the nanocomposite.

Accordingly, the first object of the present invention is to provide a clay dispersed nanocomposite having excellent mechanical properties and heat resistance, as a result of which the clay can be sufficiently peeled and dispersed.

The second object of the present invention is to provide a method for producing the clay dispersed nanocomposite.

In order to solve the first problem, the present invention provides a polymer resin comprising a continuous acrylonitrile-butadiene-styrene (ABS) copolymer and a dispersed phase polycarbonate (PC) and a quaternary ammonium containing an aromatic functional group. Provided are clay dispersed nanocomposites comprising modified clays.

In an embodiment of the present invention, the aromatic functional group includes a phenyl group, and the quaternary ammonium in the quaternary ammonium salt may have a structure of Formula 1 below.

In Formula 1, HT represents hydrogenated tallow (here, the dewing is C18 65%, C16 30%, C14 5%, and in a salt state, the anion is a monovalent anion including Cl ⁻ , F ⁻ ). .

In addition, the clay in the present invention may be montmorillonite, the clay may be 1 to 5 parts by weight based on 100 parts by weight of the polymer resin including PC and ABS, wherein the PC is 20 to 40 of the polymer resin May comprise weight percent.

In order to solve the second problem, the present invention comprises the steps of preparing a polymer resin comprising a continuous phase ABS and PC of the dispersed phase; And it provides a clay dispersed nanocomposite manufacturing method comprising the step of adding a clay surface-modified with quaternary ammonium containing an aromatic functional group to the polymer resin. The clay addition may proceed simultaneously with the manufacturing step of the polymer resin.

In addition, in one embodiment of the present invention, the aromatic functional group may include a phenyl group, and the quaternary ammonium salt may have the structure of Chemical Formula 1.

In the present invention, the clay may be montmorillonite, and may be added in an amount of 1 to 5 parts by weight based on 100 parts by weight of the polymer resin including PC and ABS, and in the polymer resin, PC may be used in an amount of 20 to 40% by weight of the polymer resin. Can occupy.

In yet another embodiment according to the present invention provides a method for producing clay dispersion nanocomposites by melt mixing the polymer resin and clay with a twin screw extruder after the clay is added.

In the clay-dispersed nanocomposite according to the present invention, the clay is sufficiently exfoliated to have a high interlayer distance, and ABS can be effectively dispersed in the nanocomposite in the continuous phase. Therefore, not only the physical properties of the nanocomposite are improved, but also the nanocomposite of the present invention in which the ABS copolymer is a continuous phase is also excellent in workability.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings and examples, but the present invention is not limited thereto.

Clay-dispersed nanocomposites according to the present invention include clays surface-modified with quaternary ammonium containing an aromatic functional group and a polymer resin comprising an ABS copolymer in a continuous phase and a PC in a dispersed phase. That is, unlike the prior art in which the PC is a continuous phase and the ABS copolymer is a dispersed phase, since the ABS copolymer is a continuous phase and the PC is a dispersed phase, as described above, workability is excellent and manufacturing cost is low. However, deterioration of physical properties such as heat resistance generated when ABS is a continuous phase is prevented by modifying clay with a quaternary ammonium salt containing an aromatic functional group, thereby improving physical properties. That is, the modified clay containing the aromatic functional group on the surface is sufficiently peeled and selectively dispersed in the continuous ABS copolymer, which is considered to be the modified clay in consideration of the ABS copolymer forming a continuous phase in the ABS / PC polymer resin. This means that the polymer layer is uniformly dispersed in the silicate layer structure throughout the polymer resin. Therefore, mechanical properties and heat resistance of the nanocomposite including the polymer resin may be improved.

This homogeneous dispersion of the modified clay for the ABS copolymer is believed to be due to the polar affinity difference that the modified clay has for the PC and ABS copolymer, which will be described in detail below.

The PC has a structure of Formula 2, and the ABS copolymer has a structure of Formula 3.

Wherein n is 10,000 to 15,000.

Wherein n is from 30,000 to 50,000.

Referring to the formulas (2) and (3), since one benzene ring is located on one side of the main chain, the ABS copolymer has an asymmetric shape as a whole, and thus the electrons tend to be biased to one side. However, since the PC tends to distribute electrons more evenly than the ABS copolymer, the ABS copolymer has a greater polarity than that of the PC. Therefore, it is determined that the above polarity difference is one cause of preventing the PC and the ABS copolymer from being completely mixed.

The clay added in the clay dispersion nanocomposite according to the present invention is modified with a quaternary ammonium salt substituted with an aromatic functional group, an example of which is the quaternary ammonium salt of Chemical Formula 1. The structure of the quaternary ammonium salt biases the electron distribution of the clay toward the aromatic functional group, thereby increasing the polarity of the clay. Therefore, the modified clay with increased polarity can be selectively dispersed in the ABS copolymer having a high polarity continuous phase. Thus, the similarity of the polarity of the modified clay and the ABS copolymer of the clay-dispersed nanocomposite according to the present invention eventually creates an environment that allows the ABS copolymer to penetrate between the silicate layered structures of the modified clay, resulting in the ABS copolymer being The silicate layered structure of the modified clay is disrupted to allow the clay to peel off and disperse nanoscale.

The prior art modified the clay with a quaternary ammonium salt having a quaternary ammonium having a structure as shown in Formula 4, which does not include an aromatic functional group such as benzyl.

In this case, when the ABS copolymer is the continuous phase and the PC is the dispersed phase, the modified clay is hardly selectively dispersed in the ABS which is the continuous phase due to the difference in polarity, but rather is distributed in the PC which is the dispersed phase. It is not evenly distributed, but rather exists in an aggregated state. Therefore, in the case of clay modified with conventional quaternary ammonium salts, since the dispersibility is not good for the polymer resin including ABS / PC in which ABS is a continuous phase, the peeling effect is rather inferior to that without using modified clay. It is explained in more detail in the following test examples.

In the present invention, the PC may be 20 to 40% by weight relative to the polymer resin including the PC and the ABS copolymer. If the content is less than 20% by weight, there is a concern that the improvement of physical properties such as mechanical strength is insufficient, and when the content exceeds 40% by weight, the amount of ABS copolymer decreases, so that the ABS copolymer does not exist continuously. Thus, the area where the clay modified according to the present invention can be selectively dispersed is reduced. In this case, it becomes difficult to uniformly disperse the clay with respect to the entire nanocomposite, and the reduction of the ABS copolymer causes a decrease in the processability and economical efficiency of the nanocomposite.

The clay may be montmorillonite, which is one of the clay minerals. The montmorillonite has a very high polarity because ions such as sodium are filled between the silicate layers and the hydroxyl group (OH ⁻ ) is present. Therefore, when montmorillonite is added to the hydrophobic nanocomposite, it is very difficult to disperse into the resin and peel off the layer. In the present invention, a quaternary ammonium salt containing an aromatic functional group was used such that the clay had a polarity similar to that of the continuous ABS copolymer.

In the present invention, the clay may be 1 to 5 parts by weight based on 100 parts by weight of the polymer resin including the ABS copolymer and PC. If the weight of the clay is less than 1 part by weight, the clay may be uniformly dispersed, but there is a concern that the effect of improving the physical properties may be insufficient due to the lack of clay content. There is.

The present invention comprises the steps of preparing a polymer resin comprising a continuous ABS ABS copolymer and a dispersed phase PC to solve the second problem; It provides a method for producing clay-dispersed nanocomposites comprising the step of adding a clay surface-modified with quaternary ammonium containing an aromatic functional group to the polymer resin. Since the clay of the present invention surface-modified as described above is sufficiently peeled and selectively dispersed in the ABS copolymer which is a continuous phase in the polymer resin, the nanocomposite produced by the manufacturing method according to the present invention has both excellent heat resistance and processability as a whole. do. The clay addition step may be performed separately from the high-rich resin manufacturing step, or may be performed simultaneously with the polymer resin manufacturing step.

In the nanocomposite manufacturing method according to the present invention uses a clay surface-modified with a quaternary ammonium salt containing an aromatic functional group, the aromatic functional group may be a phenyl group. Furthermore, in one embodiment of the present invention, the quaternary ammonium salt of Formula 1 is used as the quaternary ammonium salt, wherein the aromatic functional group is effective peeling of clay and selective dispersion of continuous ABS copolymer as described above. To make it possible.

The content of clay added in the nanocomposite manufacturing method according to the present invention is 1 to 5 parts by weight based on 100 parts by weight of the polymer resin including the ABS copolymer and PC, and the reason is as described above. The weight ratio of PC in the polymer resin may also be 20 to 40% by weight relative to the polymer resin including the PC and the ABS copolymer as described above.

In the manufacturing method according to the present invention provides a nanocomposite manufacturing method further comprising the step of melting and mixing the polymer resin and clay using a twin screw extruder after the clay addition step for effective dispersion of the clay. More specifically, this is because the montmorillonite is sufficiently peeled by the high shear force of the biaxial extruder, so that the nanoization proceeds further, and thus, clay dispersed nanocomposites having improved mechanical properties such as tensile strength can be manufactured.

Hereinafter, the present invention will be described in more detail with reference to Examples. However, the following examples are intended to illustrate the invention, the invention is not limited or limited.

Example  One

Nanocomposite Manufacturing

Dimethylbenzyl dihydrogenatedtallow quaternary ammonium chloride, where tallow is C18 65%, C16 30%, C14 5% by weight, montmorillonite Cloisite 10A (manufactured by Southern Clay, USA, After obtaining "Clay 10A" (1255 meq / 100g, organic content 39%, interlayer distance 1.92 nm), the montmorillonite was dried in a dry oven for 24 hours to remove moisture. Separately, ABS copolymer (manufactured by LG Chemical, Korea, glass transition temperature 122 ℃, weight average molecular weight 160,000, butadiene content 15% and acrylonitrile content 22%, grade RS650) was dried at 80 ℃ for 6 hours, PC (manufactured by LG-DOW, Korea, glass transition temperature 165 ℃, weight average molecular weight 28,000, polycarbonate grade 300 10) was dried at 100 ℃ for 6 hours.

Thereafter, 70 weight% of the ABS copolymer and 30 weight% of the PC are mixed to prepare a polymer resin, and the montmorillonite is added in a ratio of 1 part by weight based on 100 parts by weight of the polymer resin, followed by dry mixing for high shear biaxiality. Clay-dispersed nanocomposites were manufactured by melt extrusion using a extruder (Bautech Corporation, Korea, BA-11MM, inner diameter 11mm, length / diameter = 40) under conditions of hopper 180 ° C, barrel 240 ° C, screw rotation speed 50rpm. It was.

Example  2

Nanocomposite Manufacturing

A clay dispersion nanocomposite nanocomposite was prepared in the same manner as in Example 1 except that clay 10A was added at a ratio of 3 parts by weight based on 100 parts by weight of the polymer resin.

Example  3

Nanocomposite Manufacturing

A clay dispersion nanocomposite nanocomposite was prepared in the same manner as in Example 1, except that clay 10A was added at a ratio of 5 parts by weight based on 100 parts by weight of the polymer resin.

Comparative example  One

Clay dispersion nanocomposites were prepared in the same manner as in Example 1 except that no clay was added.

Comparative example  2

Clay-dispersed nanocomposites were prepared in the same manner as in Example 2, except that montmorillonite Cloisite 15A (hereinafter referred to as “clay 15A”) modified with dimethyl dihydrogenatedtallow quaternary ammonium chloride was used. .

Comparative example  3

The clay dispersion nanocomposite was prepared in the same manner as in Example 3, except that clay 15A was used.

Test Example  One

Clay Interlayer Distance  Test

In order to analyze the distance between the clay 10A according to the present invention and the clay 15A according to the prior art, an X-ray diffractometer (manufactured by Rigaku, Japan, D / MAX) was used to measure the nanocomposite. In order to compare the peeling effect of the clay when dispersed in Comparative Examples 1, 2, 3 and Comparative Examples 2 and 3, the nanocomposites prepared in Comparative Examples 2 and 3 were cut to less than 1mm to make a specimen and analyzed it. .

FIG. 1 shows X-ray diffraction analysis results of clays dispersed in the nanocomposites of conventional clay 15A and comparative examples 2 and 3 measured by the above-described method.

2 is an X-ray diffraction analysis of the clay dispersed in the clay 10A and the nanocomposites of Examples 1, 2 and 3 according to the present invention.

The interlayer distance of clay was calculated from Bragg's law of Equation 1 from the X-ray diffraction analysis result.

2d sinθ = nλ

First, referring to FIG. 1, the clay 15A not dispersed in the nanocomposite has an interlayer distance of 3.15 nm, but has an interlayer distance of 2.83 or 3.00 nm when dispersed in the nanocomposite. These results do not form a silicate layer in which the clay 15A is sufficiently peeled when dispersed in the nanocomposite, which means that the clay 15A cannot contribute significantly to the improvement of physical properties of the nanocomposite.

On the other hand, referring to Figure 2, the clay 10A of the present invention that is not dispersed in the nanocomposite has a distance of 1.92nm, but when dispersed in the nanocomposite has a distance of 3.53, 3.27, 2.94nm. That is, the clay 10A according to the present invention maintains a sufficiently peeled state in the nanocomposites of Examples 1 and 2 3, has excellent dispersibility in the nanocomposite, and the nanocomposite penetrates into the silicate layer of the clay to make the nano Physical properties such as heat resistance of the composite material can be improved.

In addition, this peeling effect can be directly seen through the profile of the XRD analysis result. In general, the intensity of the wide-angle X-ray diffraction (WAXD) peak represents the distance between layers of clay, and as the value decreases, the distance between layers increases. When complete peeling occurs, the peak disappears. Therefore, referring to FIG. 2, in the case of the nanocomposite according to the present invention, there is almost no such peak, and thus, the clay 10A is completely peeled and dispersed in the nanocomposite according to the present invention. However, referring to FIG. 1, it can be seen that the clay 15A, which does not contain an aromatic functional group in the quaternary ammonium, did not disappear such a peak, and thus the peeling effect did not sufficiently occur. This phenomenon is not large in the selectivity of the ABS copolymer in the continuous phase when using the clay according to the prior art, it is distributed in the PC region of the dispersed phase in the state surrounded by the continuous phase, as a result the clay is not sufficiently peeled off This is because aggregation phenomenon appears.

The reason for this phenomenon can also be found in the penetration of the nanocomposite into the clay having a plate-like structure. That is, when well dispersed in the polymer, the polymer penetrates between the plates to widen the plate spacing (d-spacing). However, since the polar affinity for the ABS copolymer of clay 15A according to the prior art is relatively low, ABS Since the copolymer does not sufficiently penetrate between the clay layers, a sufficient peeling effect does not occur. On the other hand, since the clay 10A according to the present invention has a high polar affinity for the ABS copolymer, it is possible to increase the interlayer distance by penetration of the continuous ABS copolymer between the layers of clay 10A.

Test Example  2

Morphology  Test

The clay dispersion nanocomposite of Example 3 was measured using a transmission electron microscope (TEM) (manufactured by Cal Zeiss Corporation, Germany, EM912OMEGA), and the results are shown in FIG. 3.

Referring to FIG. 3, it is confirmed that clay is not dispersed in the PC region, and that clay is selectively dispersed in the ABS copolymer region. That is, in the clay dispersed nanocomposite according to the present invention, the clay is selectively dispersed in the continuous ABS copolymer, thereby improving mechanical properties of the entire nanocomposite.

Test Example  3

Rheology  Test

Each of the clay dispersion nanocomposites of Comparative Examples 1 and 1, 2, and 3 was prepared by using a high-temperature press, and then an Advanced Rheometric Expansion System (ARES; manufactured by TA Instruments, USA) was prepared. Rheological properties (storage modulus) were measured at .1% strain and frequency of 1Hz. The temperature range was 30 ~ 190 ℃ and 5 ℃ / min. 4 shows the rheology test results.

Referring to Figure 4, it can be seen that the storage modulus increases as the clay content of the clay dispersion nanocomposites according to the present invention increases. The increase in the storage modulus is apparent at a temperature of 120 ° C. or more, which is greater than or equal to the glass transition temperature (Tg) of the ABS copolymer, which in turn implies an improvement in mechanical properties such as tensile strength.

Test Example 4

Thermal stability test

In order to analyze the thermal stability of the nanocomposites of Comparative Example 1 and Examples 1, 2, 3, TGA (Thermogravimetric Analyzer, manufactured by TY Instruments, USA, SDT Q600) after measuring the weight loss rate by temperature 5 is shown.

Referring to FIG. 5, it can be seen that the higher the clay content of the nanocomposite is, the higher the thermal decomposition temperature is, which indicates excellent thermal stability of the clay dispersion nanocomposite according to the present invention.

1 is an XRD graph of clay dispersion nanocomposites according to the prior art.

2 is an XRD graph of clay dispersed nanocomposites according to the present invention.

Figure 3 is a transmission electron micrograph of an embodiment of the clay dispersion nanocomposite according to the present invention.

Figure 4 is a graph showing the rheological test results for the embodiment of the clay dispersion nanocomposites according to the present invention.

5 is a graph showing the results of thermal stability analysis for the embodiments of the clay dispersion nanocomposites according to the present invention.

Claims (14)

A clay-dispersed nanocomposite comprising a clay modified with a quaternary ammonium salt comprising an aromatic functional group and a polymer resin comprising a continuous acrylonitrile-butadiene-styrene (ABS) copolymer and a dispersed polycarbonate. The clay dispersed nanocomposite of claim 1, wherein the aromatic functional group comprises a phenyl group. According to claim 1, wherein the quaternary ammonium salt is clay dispersed nanocomposite, characterized in that it comprises a quaternary ammonium and monovalent anion of the following structure.

(Wherein HT represents hydrogenated tallow) The clay dispersed nanocomposite of claim 1, wherein the clay is montmorillonite. According to claim 1, wherein the clay is clay dispersion nanocomposite, characterized in that 1 to 5 parts by weight based on 100 parts by weight of the polymer resin. According to claim 1, wherein the polycarbonate is clay dispersed nanocomposite, characterized in that 20 to 40% by weight of the polymer resin of the polycarbonate and the acrylonitrile-butadiene-styrene. Preparing a polymer resin comprising acrylonitrile-butadiene-styrene in a continuous phase and polycarbonate in a dispersed phase; Clay-modified nanocomposite manufacturing method comprising the step of adding a surface-modified clay to the polymer resin with a quaternary ammonium salt containing an aromatic functional group. 8. The method of claim 7, wherein the clay addition step is carried out simultaneously with the polymer resin manufacturing step. 8. The method of claim 7, wherein the aromatic functional group comprises a phenyl group. 8. The method of claim 7, wherein the quaternary ammonium salt comprises quaternary ammonium and monovalent anions having the following structure.

(Wherein HT represents hydrogenated tallow) 8. The method of claim 7, wherein the clay is montmorillonite. 8. The method of claim 7, wherein the clay is added in an amount of 1 to 5 parts by weight based on 100 parts by weight of the polymer resin. 8. The method of claim 7, wherein the polycarbonate is 20 to 40% by weight of the polymer resin. The method of claim 7, further comprising melt mixing the polymer resin and the clay using a twin screw extruder after the clay addition step.

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