KR20150067834A - Expanded polystyrene resin composition and manufacturing method thereof - Google Patents

Abstract

The present invention relates to an expandable polystyrene resin composition, including a carbon nanotube with bulk density to perform good insulation performance in a relatively low density, and a manufacturing method thereof wherein the expandable polystyrene resin composition includes 0.5-3 wt% of carbon nanotube; 0.0001-7 wt% of a blowing agent; and 97-99.4 wt% of a poly styrene resin.

Description

Expanded polystyrene resin composition and manufacturing method thereof [0002]

The present invention relates to a foamed polystyrene resin composition and a process for producing the same, and more particularly to a foamed polystyrene resin composition containing carbon nanotubes having a low bulk density so as to exhibit excellent heat insulation performance at a relatively low density. To compositions and methods of making the same.

Expanded polystyrene (EPS) is mainly used as an insulation board, and is widely used as insulation material, especially for building insulation.

Typically, the foamed polystyrenic resin obtained and commercialized has a density of 30 g / l, and at this density it is known that the thermal conductivity of the expanded polystyrene-based resin has a minimum value. Therefore, when the density of a general expanded polystyrene resin is higher than the above-mentioned density, it is not only disadvantageous in view of economical saving of the resin material and adiabatic performance, but also in the case where the density is lower than the density for the sake of material and space saving, May occur.

In order to solve these problems, it is known that by adding materials such as graphite, metal oxide, carbon black and the like to a foamable styrene resin, the heat insulating performance can be maintained or increased even at a low density. However, when a foamed resin is produced by mixing carbon black with a polystyrene-based resin, difficulties in processing and problems in product quality may arise.

For example, International Publication No. WO 94/137201 describes a process for preparing a foamed resin by mixing a polystyrene and a carbon black concentrate with an extruder, and then introducing a foaming agent into the mixture. However, the above-mentioned invention can easily achieve the purpose of producing a foam by using a carbon black concentrate containing carbon black having a particle size of 150 nm or more, because the technique of dispersing the carbon black is poor, There is a limitation in using carbon black having an average particle size of 150 nm or more.

Therefore, there is still a demand for the development of a new technique or structure capable of enhancing the heat insulating performance by being contained in the expanded polystyrene type resin.

Disclosure of the Invention In order to solve the problems described above, it is an object of the present invention to provide a foamed polystyrene resin composition comprising carbon nanotubes having a low bulk density so as to exhibit excellent heat insulation performance at a relatively low density, In particular, it is an object of the present invention to provide a method of controlling the volume density of a carbon nanotube to an optimum range to improve the heat insulating performance while using a small amount of carbon nanotubes.

The expanded polystyrene resin composition according to the present invention comprises 0.5 to 3% by weight of carbon nanotubes, 0.0001 to 7% by weight of a blowing agent, and 97 to 99.4% by weight of a polystyrene based resin.

The carbon nanotubes may have a bulk density within a range of 0.01 to 0.2 g / cc.

The carbon nanotubes may have an aspect ratio (L / D) of 100 to 1500.

The carbon nanotubes may be multi-walled carbon nanotubes.

The blowing agent may be a linear or branched hydrocarbon having 3 to 6 carbon atoms.

The blowing agent may be selected from the group consisting of n-butane, isobutane, cyclobutane, n-pentane, isopentane, neopentane, cyclopentane, n-hexane, cyclohexane and mixtures of two or more thereof.

The expanded polystyrene-based resin may have a density of 25 to 35 g / l.

The method for producing an expanded polystyrene-based resin composition according to the present invention comprises the steps of: (1) preparing a master batch of a polystyrene-based resin master batch containing carbon nanotubes; And (2) feeding the master batch to an extruder together with a polystyrene type resin, kneading and extruding the master batch and the polystyrene type resin so that the content of the carbon nanotubes is within a range of 0.5 to 3 wt% And a kneading step of supplying the blowing agent to the extruder and kneading the kneaded mixture, wherein the blowing agent is supplied to the extruder during the kneading.

The foaming agent may be supplied in an amount within a range of 2 to 7 parts by weight based on 100 parts by weight of the master batch supplied to the extruder and the polystyrene series resin.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a foamed polystyrene-based resin composition which exhibits excellent heat insulating performance at a relatively low density by using carbon nanotubes, particularly carbon nanotubes having a bulk density within a range of 0.01 to 0.2 / cc, There is an effect of providing a manufacturing method.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram showing the configuration of an extruder used in the production of the expanded polystyrene-based resin composition according to the present invention. FIG.

Hereinafter, the present invention will be described in detail with reference to specific embodiments.

The foamed polystyrene resin composition according to the present invention is characterized by containing 0.5 to 3% by weight of carbon nanotubes, 0.0001 to 7% by weight of a blowing agent, and 97 to 99.4% by weight of a polystyrene based resin.

That is, the foamed polystyrene-based resin composition according to the present invention is characterized in that it contains carbon nanotubes (CNTs) in order to improve the heat insulating performance of the foamed resin composition itself. Such carbon nanotubes have a known heat transfer coefficient of 3 It is considered that the foamed polystyrene based resin composition obtained by effectively reducing the radiation conduction can be improved in the heat insulating performance of the entire foamed polystyrene based resin composition and thus the foamed polystyrene based resin composition having a relatively low heat- . ≪ / RTI >

The carbon nanotubes may have a volume density within a range of preferably 0.01 to 0.2 g / cc, and the space occupied by the carbon nanotubes to which the carbon nanotubes having the volume densities within this range are added In order to avoid excessive use of carbon nanotubes while having an appropriate distribution pattern in a foamed polystyrene type resin composition of a carbon nanotube having a fibrous morphology so as to effectively block radiant heat conduction do. Particularly, with respect to the volume density of the carbon nanotubes, it may be desirable to have a volume density as low as possible within the above-mentioned volume density range, particularly within a range capable of providing a proper or higher adiabatic effect.

The carbon nanotubes may have an aspect ratio (L / D) of 100 to 1500, and the carbon nanotubes within the range of the aspect ratio have a length longer than the diameter, and are considered to be particularly effective in blocking radiant heat conduction.

The carbon nanotubes may be multi-walled carbon nanotubes. Multiwalled carbon nanotubes (MWCNTs) are composed of two or more walls made of carbon compared to single walled carbon nanotubes (SWCNTs). Multiwalled carbon nanotubes are single walled carbon nanotubes It differs in optical properties from nanotubes. If there is no difference in energy between the conduction band (CB) and the valence band (VB), the electrons are transferred to the conduction band from the valence band (VB) Can move freely, so that some substances become metallic and, conversely, if there is energy difference, electronic transition is not easy, so they become semiconducting or nonconductive. Due to these characteristics, the properties of single-walled carbon nanotubes and multi-walled carbon nanotubes are known to vary greatly. For example, semiconducting single-walled carbon nanotubes (assuming single-walled carbon nanotubes of constant size) emit light when excited, and then emit light as they return to the ground state. And can be used as a probe (probe). Semiconductor single-walled carbon nanotubes are widely used in bioimaging due to these characteristics. On the other hand, in the case of the multi-walled carbon nanotube, since the metallic and semiconducting single-walled carbon nanotubes are mixed, even if the electron transition occurs in the semiconducting single-walled carbon nanotube, the electrons are quickly transferred to the metallic single-walled carbon nanotube So that even if the electrons fall to the ground state, the light is not emitted, thereby the light absorbing effect is high, and it is considered to be more advantageous in blocking conduction radiation conducted in a wavelength form.

The carbon nanotubes may generally have an average outer diameter of 1 to 30 nm and an average length of 5 to 30 μm. It will be understood by those skilled in the art that such carbon nanotubes can be purchased and used commercially from leading domestic and overseas manufacturers.

The foaming agent may be a linear or branched hydrocarbon having 3 to 6 carbon atoms. Preferably, the foaming agent is at least one selected from the group consisting of n-butane, isobutane, cyclobutane, n-pentane, isopentane, neopentane, cyclopentane, Cyclohexane, and mixtures of two or more thereof.

The polystyrene-based resin may be a copolymer of a homopolymer of an aromatic vinyl monomer, preferably a styrene monomer, or a comonomer copolymerizable with the aromatic vinyl monomer. The styrene monomer may be a styrene derivative as well as styrene. The comonomer is not limited as long as it is copolymerizable with the aromatic vinyl monomer, but it may be a vinyl comonomer.

The expanded polystyrene-based resin may have a density of 25 to 35 g / l.

The foamed polystyrene resin may further include a flame retardant and / or a flame retardant additive that can be usually applied as needed, and may further include other processing aids.

The method for producing an expanded polystyrene-based resin composition according to the present invention comprises the steps of: (1) preparing a masterbatch for producing a polystyrene-based resin masterbatch containing carbon nanotubes; And (2) feeding the master batch to an extruder together with a polystyrene type resin, kneading and extruding the master batch and the polystyrene type resin so that the content of the carbon nanotubes is within a range of 0.5 to 3 wt% And a kneading step of supplying the kneaded mixture to an extruder and kneading the kneaded mixture, wherein the blowing agent is supplied to the extruder during the kneading.

The master batch preparation step (1) comprises mixing and kneading the carbon nanotubes and the polystyrene-based resin first to prepare a polystyrene-based resin master batch containing the carbon nanotubes. By using the master batch prepared through the master batch preparation step, the carbon nanotubes can be easily dispersed in the polystyrene type resin, thereby preventing biased carbon nanotubes and having uniform heat insulating properties . The content of the carbon nanotubes in the master batch is controlled by adjusting the content of carbon nanotubes in the foam polystyrene type resin composition which is ultimately obtained according to the mixing ratio of the polystyrene type resin and the master batch which are further mixed in the subsequent kneading step It is possible to prepare the master batch without limitation of the content of the carbon nanotubes. However, considering the even mixing between the carbon nanotubes and the polystyrene-based resin during the preparation of the master batch, The master batch can be prepared by mixing 80 to 99% by weight of a polystyrene type resin.

In the kneading step (2), the master batch obtained in the master batch preparation step is fed to an extruder together with a polystyrene type resin, kneaded and extruded, and the content of the carbon nanotubes is adjusted to 0.5 to 3 wt% And the master batch and the polystyrene type resin are fed to the extruder and kneaded. Therefore, the content of the carbon nanotubes in the expanded polystyrene-based resin composition finally obtained regardless of the content of the carbon nanotubes in the master batch in the master batch preparation step can be made constant.

Thereafter, the foaming agent is supplied to the extruder and foamed.

At this time, the extruder used for the foaming is not limited. For example, the extruder may be a uniaxial or biaxial extruder, and preferably an extruder having a typical configuration as shown in Fig. The operation conditions of the extruder may be set normally, and may be suitably operated according to the kind of the base material and the additive. In typical operation conditions, the extruder is rotated at a rotation speed of 150 to 300 rpm And mixing and kneading are carried out. The temperature of the barrel to which the extruded barrel is fixed may be in the range of 120 to 250 ° C, but the present invention is not limited to these operating conditions.

During the extrusion through the extruder or after the extrusion is completed, foaming by the foaming agent is carried out to obtain the desired expanded polystyrene type resin composition. As a specific example, the blowing agent may be directly injected into an extruder in which the polystyrene-based resin and the master batch are in a molten state, and then quenched at the outlet of the extruder to produce an extruded foam.

The foaming agent is preferably used to obtain an extrudate having an appropriate density to be fed in an amount within a range of 2 to 7 parts by weight based on 100 parts by weight of the master batch fed to the extruder and the total of the polystyrene series resin.

However, the present invention is not limited to the above-mentioned extrusion method. Alternatively, the extruded product may be extruded without extrusion of the blowing agent to introduce the extrudate into a pressure vessel, impregnating the extruded product with a blowing agent under a predetermined temperature and pressure, A foamed product may also be produced.

According to the above-described method, a foam of a polystyrene type resin in the form of a spherical bead, a disk or a cylindrical pellet having an average diameter of 0.1 to 2.0 mm, that is, a foamed polystyrene resin composition can be obtained. And has a thermal conductivity of less than 34 mW / mK as measured, for example, in accordance with DIN 52612 at a density within the range of 15 to 35 g / l.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope and spirit of the invention as disclosed in the accompanying claims. Changes and modifications may fall within the scope of the appended claims.

[Example]

Example 1

10% by weight of NC7000 (diameter: 9.5 nm, length: 1.5 μm, volume density: 0.06 g / cc) of Nanocyl, a commercialized carbon nanotube, was mixed with 90% by weight of polystyrene resin and kneaded to prepare a master batch Respectively. 1, the polystyrene and the master batch were fed into the twin-screw extruder while the extruded amount of the carbon nanotubes was controlled to be 1.0 wt% And 50 parts by weight of n-butane as a foaming agent were charged and foamed to obtain foamed products (foamed polystyrene-based resin compositions) having densities of 30.29 g / L, 30.8 g / L and 30.9 g / L and the thermal conductivities of the respective foams Measured according to DIN 52612, and the results are shown in Table 1 below.

Example 2

Carbon nanotubes were obtained in the same manner as in Example 1 except that the amount of the masterbatch was adjusted so that the amount of extrusion of the carbon nanotubes was 1.5% by weight of the total amount of extrusion, The thermal conductivity of each of the foams was measured according to DIN 52612, and the results are shown in Table 1 below.

division CNT content
(weight%) CNT volume density
(g / cc) Foam density
(g / l) Thermal conductivity
(mW / mK)
Example 1
1.0
0.06 30.29 31.00 31.10 30.80 31.12 30.90
Example 2
1.5
0.06 29.91 30.80 30.45 30.50 31.03 30.60 CNT = carbon nanotube,
CNT content (wt%) = carbon nanotube content (wt%) in the foam

According to the present invention, it is possible to achieve a relatively low thermal conductivity in a relatively low-density foamed material by increasing the content of the inventions according to the present invention, particularly the content of carbon nanotubes.

(Without reference numerals)

Claims (9)

0.5 to 3% by weight of carbon nanotubes, 0.0001 to 7% by weight of a foaming agent and 97 to 99.4% by weight of a polystyrene-based resin.
Expanded polystyrene type resin composition. The method according to claim 1,
Wherein the carbon nanotubes have a bulk density within a range of 0.01 to 0.2 g / cc.
Expanded polystyrene type resin composition. The method according to claim 1,
Wherein the carbon nanotubes have an aspect ratio (L / D) of 100 to 1500
Expanded polystyrene type resin composition. The method according to claim 1,
Wherein the carbon nanotubes are multi-walled carbon nanotubes.
Expanded polystyrene type resin composition. The method according to claim 1,
Wherein the blowing agent is a linear or branched hydrocarbon having 3 to 6 carbon atoms
Expanded polystyrene type resin composition. 6. The method of claim 5,
Characterized in that the foaming agent is selected from the group consisting of n-butane, isobutane, cyclobutane, n-pentane, isopentane, neopentane, cyclopentane, n-hexane, cyclohexane and mixtures of two or more thereof
Expanded polystyrene type resin composition. The method according to claim 1,
Characterized in that the expanded polystyrene-based resin has a density of 25 to 35 g / l
Expanded polystyrene type resin composition. (1) preparing a master batch for producing a polystyrene-based resin master batch containing carbon nanotubes; And
(2) The master batch is supplied to an extruder together with a polystyrene type resin and kneaded and extruded. The master batch and the polystyrene type resin are fed to the extruder (2) so that the content of the carbon nanotubes is within a range of 0.5 to 3% To knead the mixture;
, ≪ / RTI &
And a foaming agent is supplied to the extruder during the kneading.
A method for producing an expanded polystyrene type resin composition. 9. The method of claim 8,
Wherein the foaming agent is supplied in an amount within a range of 2 to 7 parts by weight based on 100 parts by weight of the master batch and the total of the polystyrene series resin supplied to the extruder
A method for producing an expanded polystyrene type resin composition.

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