KR20020094121A - Nanocomposite of regenerated polypropylene and clay - Google Patents

Abstract

PURPOSE: A nanocomposite of a regenerated polypropylene and clay and a container for an aircraft unit loading container prepared by using the composition are provided to improve the flame retardancy and the lightweight of the container without deterioration of the strength. CONSTITUTION: The nanocomposite comprises 100 parts by weight of a regenerated polypropylene; 2-10 parts by weight of clay modified organic-friendly by being mixed with an organic modifier; and 2-20 parts by weight of a phenol resin. Preferably the organic modifier is selected from the group consisting of dimethyl dihydrogenated-tallow ammonium, dimethylbenzyl hydrogenated-tallow ammonium and dimethyl hydrogenated-tallow (2-ethylhexyl)ammonium. The clay comprises phyllosilicate comprising aluminum or magnesium silicate layers charted anionically; and a sodium ion or a potassium ion charging the space between the layers.

Description

Nanocomposite of Regenerated Polypropylene and Clay

The present invention relates to nanocomposites of recycled polypropylene and clay, and more particularly, to regenerated polypropylene and organic modifiers having excellent flame retardancy of about 100% or more than pure polypropylene. The present invention relates to a nanocomposite in which silicates of a layered structure modified by mixing are mixed.

The nanocomposite of recycled polypropylene and clay according to the present invention is manufactured as a layered product by extrusion and used in a container for a unit-mounted container of an aircraft.

As high technology industries such as the electronics, aviation, and automotive industries develop, materials with unique properties are needed to meet these industrial characteristics. In order to meet the necessity of such materials, composite materials, in particular nanocomposites, have been widely studied.

Among these nanocomposites, nanocomposites of polymers and clays have advantages in that they have excellent tensile strength, tensile modulus, dimensional stability, and heat resistance even with a small amount of clay, and have a property of decreasing permeability to various gases.

Therefore, in the past decades, a method of improving the properties of a polymer by preparing a nanocomposite by mixing a polymer and a specific amount of clay has been proposed. Since a polymer is generally a nonpolar organic material, a clay is a much polar inorganic material. Their mixing was poor.

In order to overcome this difficulty, a method of polymerizing a polymer forming a matrix using monomers in the presence of clay has been proposed. This was because clay was thought to be more easily mixed with monomers than polymers. However, it has been found that this method produces a heterogeneous nanocomposite that does not have desirable physical properties. Because clay has a layered structure that cannot be easily broken, it is difficult to obtain a homogeneous mixture.

In the case of the nanocomposite of polypropylene and clay, in order to improve the affinity between polypropylene and clay, first, a polypropylene oligomer modified with maleic anhydride is prepared, and then inserted into clay and then mixed with polypropylene. It was also prepared a nanocomposite of polypropylene and clay, which did not have excellent mechanical properties.

On the other hand, the unit-mounted container described above is a set of containers for air cargo used only for air transportation, when using a unit-mounted container designed for the shape of the aircraft cargo compartment when transporting a large amount of air cargo can protect the cargo. In addition, the transportation of special cargoes can be facilitated, and freight transportation operations and handling can be performed quickly, thereby reducing operating time and increasing the operation rate of the aircraft.

However, in the related art, since the unit-mounted container was manufactured by a heavy aluminum plate, the load of the container itself occupies 10% of the cargo load. In other words, as the weight of the container increases, it is impossible to carry more cargo of the weight corresponding to the weight, thereby reducing the transportation efficiency and increasing fuel consumption.

In addition, the conventional layered products made of pure polypropylene had a problem that the strength was not enough to be used as a unit mounting container, so that the weight of the unit mounting container was reduced to lightness while being equivalent to the strength of aluminum. There is a need for materials.

Accordingly, an object of the present invention is to provide a nanocomposite having excellent physical properties in which regenerated polypropylene and silicate of a layered structure that is organically modified by an organic agent are mixed in order to solve the conventional problems.

1 is a heat flow graph of the regenerated polypropylene used in the present invention measured by a differential scanning calorimeter.

2 is an X-ray diffraction pattern measured from the nanocomposite according to the present invention.

Figure 3 is a graph of heat generation rate measured from the nanocomposite according to the present invention.

The present invention provides a nanocomposite having excellent physical properties formed by recycled polypropylene and clay in order to achieve the above object.

Hereinafter, the present invention will be described in detail.

The nanocomposites of the present invention consist of recycled polypropylene, clays and phenolic resins.

First, the recycled polypropylene used in the present invention is recycled waste polypropylene by dissolution and regeneration method, and it is prepared by dissolving waste oil such as waste oil and then adding an adhesive and mixing it with sand, clay, etc. as a filler, and forming it under pressure. It has about 100% better flame retardancy than pure polypropylene.

Table 1 below shows the results of measuring physical properties of the recycled polypropylene.

TABLE 1

Item unit result Test method (year of issue) Melt index g / 10min 2.2 ASTM D1238 (1999) Tensile Strength (Yield Point) kgf / ㎠ 229 ASTM D638 (1999) Elongation Rate (Yield Point) % 8.7 Flexural strength kgf / ㎠ 319 ASTM D790 (2000) Flexural modulus kgf / ㎠ 15,200 Izod impact strength kgfcm / cm 8.6 ASTM D256 (1997) importance - 1.209 ASTM D792 (1998)

As the regenerated polypropylene is melted at 130 ° C. and 167 ° C. as shown in the heat flow graph measured by the differential scanning calorimeter of FIG. 1, the processing temperature when preparing the nanocomposite of the present invention is pure polypropylene. It should be slightly lower than the processing temperature of 230 to 250 ℃ when used.

Second, the clay used in the present invention is based on silicate of nano-scale layered structure, and may be natural clay or synthetic clay.

In its form, a phyllosilicate consisting of an anionically charged aluminum or magnesium silicate layer having a thickness of 7 to 12 microns and a sodium ion (Na ⁺⁾ filling between these anionically charged aluminum or magnesium silicate layers. Or small cations such as potassium ions (K ⁺ ).

Specific examples of the phyllosilicates according to the present invention include montmorillonite, hectorite, saponite, beadellite, nontronite, vermiculite or halosite. halloysite and the like, which impart very desirable mechanical properties and heat resistance to the nanocomposite.

However, since the clay used in the present invention has a strong polarity in the unmodified state, in order to mix well with the non-polar organic polymer, it has to be somewhat polarized.

To this end, in the present invention, the clay is mixed to an organic affinity and mixed with an organic agent to give the clay a certain degree of polarity, thereby providing compatibility with non-polar organic polymer regenerated polypropylene.

The organic agent may be dimethyl dihydrogenated-tallow ammonium, dimethyl benzyl hydrogenated-tallow ammonium, or dimethyl hydrogenated-tallow (2-ethyl Hexyl) ammonium (Dimethyl hydrogenated-tallow (2-ethylhexyl) ammonium) is used to organically modify the clay.

In other words, the organically-modified clay according to the present invention has a low molecular weight organizing agent inserted into a phyllosilicate having a strong van der Waals attraction as a basic unit of clay, so that sodium or potassium ions located inside the phyllosilicate are hydrogenated. By substitution with hydrogenated-tallow alkyl, the clay becomes organic-friendly and the d-spacing of phyllosilicates is widened.

The characteristics of such organically modified clays can be characterized by anionic surface charge, that is, cation exchange capacity expressed in meq / 100g.

The organically-modified clay in the present invention preferably has a cation exchange capacity of 30 to 250 meq / 100 g because of the strong interaction of the phyllosilicate and the organic agent if it has a cation exchange capacity of greater than 250 meq / 100 g. This is because it becomes difficult to peel off the phyllosilicate into the nanoscale sheet, and when the cation exchange capacity is less than 30 meq / 100 g, the interaction between the phyllosilicate and the organic agent is reduced.

In addition, the moisture content is preferably 1 to 3%, the weight loss rate when igniting is preferably 30 to 50%.

Therefore, when the organically modified clay is dispersed in the regenerated polypropylene described above, the regenerated polypropylene is intercalated into the space of the phyllosilicate having an increased interlayer distance, and the interlayer distance is further increased by the insertion of the regenerated polypropylene. When increased, phyllosilicates can be exfoliated onto nanoscale sheets and irregularly dispersed in recycled polypropylene.

Third, the phenolic resin used in the present invention is a resin having excellent flame retardancy, which is first crosslinked to exist as individual particles by phase separation of regenerated polypropylene and phenol, thereby increasing the overall flame retardancy. Bring it.

In the present invention, 100 parts by weight of regenerated polypropylene, 2 to 10 parts by weight of clay modified by an organic agent, and 2 to 20 parts by weight of phenol resin are used to prepare a nanocomposite.

According to the method for preparing a nanocomposite according to the present invention, first, an organic clay is organically prepared by organizing clay with an organic agent, and then 100 parts by weight of recycled polypropylene and 2 to 10 parts by weight of organically modified clay and phenol 2 to 20 parts by weight of a pellet obtained by melt mixing under conditions of a column temperature of 210 to 250 ° C. and a speed of 180 to 350 rpm using a twin screw extruder is pelletized, and the pellet is 78 to After drying under vacuum at 82 ° C., the dried pellet is injected into a nanocomposite under conditions of a cylinder temperature of 180 to 200 ° C. and a mold temperature of 25 to 35 ° C.

The present invention also provides a container for an aircraft unit-mounted container manufactured by a layered product using the nanocomposite as a material.

Such container unit container for aircraft of the present invention is a hexahedron having a thickness of 1.0 to 4.0 mm using rivets, bolts and welding to meet the standards and specifications specified by the International Air Transport Association (IATA) by a conventional method. Are manufactured.

Hereinafter, the present invention will be described in detail with reference to Examples. However, the examples are only to illustrate the invention and the present invention is not limited by the following examples.

Example 1 Preparation of Organo-Friendly Modified Clay

Na ⁺ -montmorillonite was dispersed in distilled water with tertiary deionization and left for 3 days. Sodium chloride (NaCl) was added to Na ⁺ -montmorillonite in powder form, stirred at 75 ° C for 24 hours, and centrifuged at 10,000 rpm. . Was added to 0.1N of silver nitrate (AgNO ₃₎ solution was then centrifuged to separate the liquid chlorine ion (Cl ^-) repeatedly washed with distilled centrifuged until no detection Na ⁺ - montmorillonite was obtained.

The Na ⁺ -montmorillonite was dispersed in water at about 80 DEG C using a stirrer to form a mixture of Na ⁺ -montmorillonite and water, and then dissolved in water, an organic dimethyl dihydrogenated-tallow ammonium and hydrochloric acid (HCl). The mixture was mixed with Na ⁺ -montmorillonite and water, and stirred vigorously for about 5 minutes until a white precipitate formed. The precipitate produced at this time was removed using a glass filter, washed three times in water at about 80 ° C., and lyophilized, resulting in 95 meq / 100 g of cation exchange capacity, 2% water content, and 38% weight loss upon ignition. Organo-friendly modified clays having properties were prepared.

Example 2 Preparation of Nanocomposites of the Invention

100 parts by weight of regenerated polypropylene, 3.5 parts by weight of organically-modified clay prepared in Example 1, and 3 parts by weight of phenol resin were melted under the conditions of a column temperature of 210 to 250 ° C. and a speed of 300 rpm using a twin screw extruder. The strand obtained by melting mixing is made into pellets, the pellets are dried under vacuum at 80 ° C, and then the dried pellets are injected under conditions of a cylinder temperature of 200 ° C and a mold temperature of 30 ° C. Nanocomposites were prepared.

Example 3. Preparation of Nanocomposites of the Present Invention

A nanocomposite of the present invention was prepared in the same manner as in Example 2, except that 6 parts by weight of phenol resin was used instead of 3 parts by weight.

Example 4 Preparation of Nanocomposites of the Invention

A nanocomposite of the present invention was prepared in the same manner as in Example 2, except that 9 parts by weight of phenol resin was used instead of 3 parts by weight.

Experimental Example 1. X-ray Diffraction Test

The X-ray diffraction test results of the nanocomposites of Examples 2 to 4 are shown in FIG. 2, and the results of the first peak (2θ) and the interlayer distance (d-spacing) for them are shown in Table 2 below. .

For comparison, the X-ray diffraction test was performed using the organically modified clay of Example 1, and the results are shown together in FIG. 2.

At this time, X-ray diffraction test was performed using M18-X-ray of MAC Science of Japan with CuKa (λ = 0.154 nm) radiation and curved graphite crystal monochromator. The change in the characteristic peak of the nanocomposite was observed by measuring θ = 1 to 10 at 40 kV, 50 mA, and 1 ° C./min.

TABLE 2

First peak (2θ) D-spacing Clay of Example 1 3.62 ° 24.4 Å Nanocomposites of Example 2 2.16 ° 40.9Å Nanocomposites of Example 3 2.24 ° 39.4Å Nanocomposites of Example 4 2.08 ° 42.5Å

As shown in Table 2, 2θ of the clay of Example 1 was 3.62 °, and the interlayer distance was 24.4Å. On the contrary, the 2θ of the nanocomposite of Example 2 was 2.16 ° and the interlayer distance was 40.9Å, the 2θ of the nanocomposite of Example 3 was 2.24 ° and the interlayer distance was 39.4Å, and the nano of Example 4 2θ of the composite was 2.08 ° and the interlayer distance was 42.5Å.

From this, it can be inferred that the nanocomposite was prepared by intercalation of the regenerated polypropylene into the organic affinity-modified clay.

Experimental Example 2 Flame Retardant Analysis

In order to analyze the flame retardancy of the nanocomposites of Examples 2 and 4, the measurement of cone calorimeter (Fire Testing Technology Ltd.) was performed under ASTM E1354 standard conditions under conditions of 50 kW / m 2 heat rate and 0.024 m 3 / sec. The heat generation rate over time was measured, and the result is shown in FIG. 3, and the heat generation rate was measured using regeneration polypropylene alone for comparison.

In the case of recycled polypropylene, since it is known that the flame retardancy is improved by about 100% or more than that of pure polypropylene, according to FIG. 3, the flame retardancy of the nanocomposite of the present invention is improved by about 60% compared to the flame retardancy of the recycled polypropylene. As a result, the flame retardancy of the nanocomposite of the present invention can be seen to be improved by about 200% compared to pure polypropylene.

As described above, in the present invention, a nanocomposite exhibiting excellent improvement in strength and flame retardancy is produced by inserting regenerated polypropylene into an organically modified clay by an organic agent.

In addition, the unit-mounted container manufactured by the layered product made of the nanocomposite of recycled polypropylene and clay according to the present invention has superior strength compared to the unit-mounted container manufactured by the layered product made of only the conventional recycled polypropylene. It has the advantage that the flame retardancy is improved, and also significantly lighter than the unit-mounted container manufactured by the conventional aluminum plate to improve fuel efficiency and transportation efficiency.

Therefore, when manufacturing a unit-mounted container, the aluminum frame is used as it is only at the corners, and other parts can be manufactured using a layered product made of the nanocomposite of the present invention.

Claims (5)

Nanocomposite comprising 100 parts by weight of regenerated polypropylene and 2 to 20 parts by weight of organically modified clay and 2 to 20 parts by weight of phenol resin by mixing an organic modifier. . The method of claim 1, The organicating agent is dimethyl dihydrogenated-tallow ammonium, dimethylbenzyl hydrogenated-tallow ammonium and dimethyl hydrogenated-tallow (2-ethyl Hexyl) ammonium (Dimethyl hydrogenated-tallow (2-ethylhexyl) ammonium) nanocomposite, characterized in that it is selected from the group consisting of. The method of claim 1, The clay is a phyllosilicate consisting of anionically charged aluminum or magnesium silicate layers and sodium ions (Na ⁺ ) or potassium ions (K ⁺ ) filling between these anionically charged aluminum or magnesium silicate layers. Nanocomposite, characterized in that consisting of. The method of claim 3, wherein The phyllosilicate is selected from the group consisting of montmorillonite, hectorite, saponite, baydellite, nontronite, vermiculite and halloysite Nanocomposite, characterized in that. A container for an aircraft unit mounting container, which is manufactured by a layered product using the nanocomposite of claim 1 as a material.