KR20030027157A - Nanocomposite of Nylon 6 - Google Patents

Abstract

PURPOSE: A nylon 6 nano composite is provided to enhance the ductility and the impact property by the structural change which produces a crystal having the melting point of 230 to 250 deg.C. CONSTITUTION: The nylon 6 nano composite obtained from an organized montmorillonite, a coupling agent and a nylon 6 resin is characterized in that a crystal having the melting point of 230 to 250 deg.C exists in the nano composite. The nylon 6 nano composite has the ductility of 7.0 to 20.0 %, the impact strength of 7.0 to 12.0 kg.cm/cm and the flexion elasticity of 35000 to 60000 kg/cm2. The organized montmorillonite is one surface treated with the organic chemicals having the alkyldiamine terminal group represented by a formula of H2N(CH2)nNH2(wherein, n is an integer of 6 to 20).

Description

Nylon 6 Nanocomposite {Nanocomposite of Nylon 6}

The present invention relates to a nylon 6 nanocomposite, and more particularly, nylon 6 prepared by mixing a coupling agent and a nylon 6 polymer resin with a compounding method by using montmorillonite surface-treated with an organic agent containing an alkyldiamine group at the end. It relates to a nanocomposite.

Polymer nanocomposite manufacturing technology using clay minerals is a technology in which clay minerals having a silicate layered structure such as montmorillonite are peeled into nanoscale plate-based units and dispersed in polymer resins. It is a way to improve the mechanical properties to the level of engineering plastics.

However, since it is very difficult to peel and disperse the plate-shaped montmorillonite in the polymer resin as described above, in order to solve this problem, the penetration of the polymer resin is enhanced by inserting a low molecular weight organizing agent between the clay minerals and widening the gap between the plate silicates. The method of making it easy is used.

The method of separating clay minerals into nano-scale plate-shaped basic units and dispersing them in a polymer resin includes a solution method, a polymerization method, and a compounding method. Among them, the polymerization method and the compounding method have been studied in the 80s and 90s, respectively. It is a technology that has been commercialized in advanced countries such as the US and Japan.

In particular, the compounding method is to insert the polymer chain in the molten state between the clay mineral silicate layer and then mechanically mix it to disperse the clay mineral.In 1993, Cornell's research team inserted polystyrene melt directly to produce interlayer nanocomposites. In 1997, the Toyota Research Institute of Japan announced the technology of manufacturing peelable polypropylene nanocomposites by compounding method.

According to Toyota's technique, the conventional inorganic fillers, which are usually added during compounding to improve the mechanical and thermal properties of the polymer, are agglomerated and dispersed in the polymer chain with a particle size of 1 micron or more. Compared with the amount, the improvement of the mechanical and thermal strength was weak.

On the other hand, looking at the prior art of manufacturing such a nanocomposite, in Japanese Patent Publication No. 60-108463 and Japanese Patent Publication No. 60-47061, after modifying the surface of the clay mineral with an alkylamino acid-based organic agent, reacted with nylon monomers The polymerized nylon nanocomposite was prepared, but there was a disadvantage in that elongation and impact properties were greatly reduced.

In addition, US Pat. No. 4,874,728 uses clay minerals whose surface is modified with an alkylamino acid-based organic agent and a coupling agent such as alkoxy, acetoxy, or halosilyl-based organic silane, but this also improves elongation and impact strength. I could not.

In other words, the nanocomposites prepared using polyamide polymers have excellent stiffness and heat resistance even with the addition of a small amount of inorganic materials, but their elongation and impact strength are significantly lower than those of conventional inorganic fillers. Since there is a limitation in use, it is urgent to solve the problem accordingly.

Accordingly, the present inventors, while trying to solve the above problems, by using montmorillonite surface-modified with an organicating agent containing an alkyldiamine group at the end and compounding a polyolefin-based coupling agent grafted maleic hydride The prepared nylon 6 nanocomposite was found to have excellent elongation and impact strength by forming a structural change in which crystals were formed at a melting point of 230 to 250 ° C., which was not found in the conventional nylon 6, thereby completing the present invention.

Accordingly, an object of the present invention is to compound the organic montmorillonite and maleic hydride-grafted polyolefin-based coupling agent surface-treated with an organic agent containing an amine group having excellent reactivity at both ends of the alkyl group to increase the elongation and impact strength It is to provide a nylon 6 nanocomposite that can be improved.

The nylon 6 nanocomposite of the present invention for achieving this purpose is prepared from organicized montmorillonite, coupling agent and nylon 6 resin, wherein the nanocomposite is characterized by the presence of crystals having a melting point of 230 to 250 ° C. It is done.

1 is a diagram showing the results of differential scanning thermal analysis (DSC) of the nylon 6 nanocomposite obtained according to Example 1,

2 is a diagram showing the results of differential scanning thermal analysis (DSC) of the nylon 6 nanocomposite obtained according to Example 2,

3 is a diagram showing the results of differential scanning thermal analysis (DSC) of the nylon 6 nanocomposite obtained according to Example 3,

4 is a diagram showing the results of differential scanning thermal analysis (DSC) of the nylon 6 nanocomposite obtained according to Example 4,

5 is a diagram showing the results of differential scanning thermal analysis (DSC) of the nylon 6 nanocomposite obtained according to Comparative Example 1,

6 is a diagram showing the results of differential scanning thermal analysis (DSC) of the nylon 6 nanocomposite obtained according to Comparative Example 2,

7 is a diagram showing the results of differential scanning thermal analysis (DSC) of the nylon 6 nanocomposite obtained according to Comparative Example 3,

8 is a diagram showing the results of differential scanning thermal analysis (DSC) of the nylon 6 nanocomposite obtained according to Comparative Example 4.

The present invention will be described in more detail as follows.

The nylon 6 nanocomposite according to the present invention is obtained by melting and mixing montmorillonite and a coupling agent surface-treated with an organic agent through nylon 6 through a compounding method, and looking at the specific composition thereof as follows.

(1) Organicated montmorillonite surface-treated with an organic agent containing an alkyldiamine group at the terminal

In order to prepare the nylon 6 nanocomposite of the present invention, first, an organicized montmorillonite surface-treated with an organic agent containing an alkyldiamine group at the end should be prepared.

As used herein, the alkylating agent of the alkyldiamine type has excellent reactivity with the maleic hydride group in the coupling agent used in the present invention because the amine group having excellent reactivity is bonded to both ends of the alkyl group as shown in the following formula (1). The effect of improving elongation and impact strength is excellent.

H ₂ N (CH ₂ ) _n NH ₂

Where n is an integer between 6 and 20.

On the other hand, it is preferable that the added amount of the organicized montmorillonite is 2 to 10% by weight of the total nanocomposite. If the content is less than 2% by weight, the dispersion of nano clay minerals is so active that the flexural modulus decreases. If it exceeds 10% by weight, elongation and impact strength are inferior.

(2) coupling agent

The coupling agent is used for the purpose of improving compatibility between the nylon 6 resin, which is a base polymer, and the organicized montmorillonite, which is an inorganic filler, and specifically, the surface of montmorillonite organicized with an olefin oligomer resin having a number average molecular weight of 10,000 or less. The maleic hydride which can chemically bond the nylon 6 resin which is a base polymer is grafted, and the addition amount is 0.5 to 5 weight% of all nanocomposites. In the present invention, Eastman's Epolene C-18 having a number average molecular weight of 5,700 was used.

If the number average molecular weight of the olefin-based oligomer resin exceeds 10,000, there is a problem in that elongation and impact strength are lowered due to poor compatibility with nylon 6 resin, which is a base polymer.

In addition, when the amount of the coupling agent is less than 0.5% by weight, the addition amount is insufficient, and the effect of improving the elongation and impact strength is insufficient, and when the amount of the coupling agent is more than 5% by weight, the flexural modulus is lowered, so that the purpose of the nanocomposite cannot be achieved. The addition amount thereof is preferably 0.5 to 5% by weight based on 100% by weight of the total resin composition.

(3) nylon 6 resin

Nylon 6 resin, which is the base polymer of the nanocomposite of the present invention, can be used conventionally, and typically nylon 6 resin has a? -Crystal at a melting point of about 210 ° C and an α-crystal at about 220 ° C.

On the other hand, a heat stabilizer, a releasing agent, a weathering agent, or a pigment can be added within a range not impairing the object of the present invention.

The nanocomposite thus obtained has a new crystal having a melting point of 230 to 250 ° C. With these structural changes, physical properties such as elongation and impact strength are excellent.

On the other hand, the manufacturing process of the nylon 6 nanocomposite of the present invention will be described in detail.

First, a nylon 6 resin, a coupling agent, and organicized montmorillonite are introduced into a twin screw extruder, and melt-kneaded to prepare a chip (CHIP). After drying the prepared chip, each specimen is manufactured using a screw-type injection machine.

Evaluation of physical properties of the fabricated specimens is carried out as follows.

1) Elongation: Dumbbell-type specimens of 1/8 inch were prepared according to ASTM D638, and measured at a speed of 50 mm / min.

2) Impact strength: According to ASTM D256, 1/4 inch specimens were prepared, and the Izod Notched impact strength was measured at room temperature.

3) Flexural modulus: A 1/4 inch specimen was prepared according to ASTM D790, and measured at a speed of 5 mm / min.

4) Melting point measurement: using a differential scanning thermal analyzer (DSC) was measured at a temperature increase rate of 20 ℃ / min to 25 ~ 280 ℃.

Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited by the Examples.

Examples 1-4

The montmorillonite organicated with nylon 6 polymer resin, C-18 coupling agent and dodecyldiamine (H ₂ N (CH ₂ ) ₁₂ NH ₂ ) was melt-kneaded in a twin screw extruder heated at 245 ° C. to form a chip. It was. The composition and content of nylon 6, the coupling agent and the organicized montmorillonite are shown in Table 1 below. In addition, the organic agent used in each example is as shown in Table 1 below.

After drying for 5 hours using a dehumidifying dryer, a specimen was prepared at the same temperature as melt kneading using a heated screw-type injection machine.

Elongation, impact strength, flexural modulus, melting point, and the like were measured using the prepared specimens in the same manner as described above, and the results are shown in Table 2 below.

On the other hand, the DSC results of the nanocomposites obtained in Examples 1 to 4 are shown in Figs.

Example One 2 3 4 Nylon 6 (% by weight) 94 90 92 88 Coupling Agent ⁽¹⁾ (wt%) 2 2 4 4 Organized Montmorillonite Content (% by weight) 4 8 4 8 Organizing agent H ₂ N (CH ₂ ) ₁₂ NH ₂ H ₂ N (CH ₂ ) ₁₀ NH ₂ H ₂ N (CH ₂ ) ₆ NH ₂ H ₂ N (CH ₂ ) ₈ NH ₂ (1) Epolene C-18, number average molecular weight 5,700, manufactured by Eastman.

Example One 2 3 4 Elongation (%) 10.5 7.2 15.0 13.4 Impact Strength (kgcm / cm) 8.2 7.5 11.3 10.2 Flexural modulus (kg / ㎠) 46,100 57,200 47,900 55,400 Melting Point (℃) γ-crystal 210 210 211 211 α-crystal 220 221 221 221 x -determination 240 239 240 240 X-crystals: Refers to the newly discovered crystals in the present invention.

Comparative Examples 1 to 4

Comparative Examples 1 to 4 are examples of preparation of nanocomposites outside the composition range of the present invention, the contents of which are shown in Table 3 below, and the physical properties were evaluated in the same manner as in the above Examples, and the results are shown in Table 4 below. Indicated.

On the other hand, the DSC results of the nanocomposites obtained according to Comparative Examples 1 to 4 are shown in Figs.

Comparative example One 2 3 4 Nylon 6 (% by weight) 96 92 94 88 Coupling Agent ⁽¹⁾ (wt%) - - 2 4 Organized Montmorillonite (wt%) A ⁽²⁾ 4 8 - - B ⁽³⁾ - - 4 8 (Note) (1) Epolene C-18 , the number average molecular weight 5,700, East things _{product. (2) H 2 N (} CH 2) will the organized into _{12 NH 2. (3) H} 2 N (CH 2) 11 CH Organicated to ₃ .

Comparative example One 2 3 4 Elongation (%) 5.8 5.2 3.1 4.2 Impact Strength (kgcm / cm) 6.2 4.8 4.2 3.9 Flexural modulus (kg / ㎠) 25,300 28,400 25,700 32,500 Melting Point (℃) γ-crystal Appears together in the α-crystal peak. α-crystal 222 223 222 224 x-the decision Not found X-crystals: Refers to the newly discovered crystals in the present invention.

From the results of Tables 2 and 4, it can be seen that the nylon 6 nanocomposite of the present invention is excellent in elongation and impact strength with structural changes according to the new melting point at 230 ~ 250 ℃.

In addition, it can be clearly seen from FIGS. 1 to 4 and 5 to 8 that the nylon 6 nanocomposite of the present invention has a crystal showing a melting point of 230 to 250 ° C.

As described in detail above, according to the present invention, organic montmorillonite surface-treated with a nylon 6 resin, an olefin oligomer resin having a number average molecular weight of 10,000 or less, and a coupling agent and an alkylating agent of an alkyldiamine type are grafted with maleic anhydride. As a result of preparing the nylon 6 nanocomposite, it was confirmed that not only the structural change in which the new melting point appeared at 230 to 250 ° C. but also the low elongation and impact strength of the conventional nylon 6 nanocomposite could be improved.

Claims (4)

In the nylon 6 nanocomposites obtained from organicized montmorillonite, coupling agents and nylon 6 resins, The nanocomposite is nylon 6 nanocomposite, characterized in that the presence of a crystal showing a melting point of 230 ~ 250 ℃. The nylon 6 nanocomposite of claim 1, wherein the nanocomposite has elongation of 7.0 to 20.0%, impact strength of 7.0 to 12.0 kg · cm / cm, and flexural modulus of 35,000 to 60,000 kg / cm 2. The nylon 6 nanocomposite according to claim 1, wherein the organicized montmorillonite is surface-treated with an organic agent containing an alkyldiamine group represented by the following formula (1) at the end thereof, and the content thereof is 2 to 10 wt%. Formula 1 H ₂ N (CH ₂ ) _n NH ₂ , Where n is an integer between 6 and 20 The nylon 6 nanocomposite of claim 1, wherein the coupling agent is a polyolefin-based coupling agent grafted with maleic hydride, and its content is 0.5 to 5 wt%.