KR20140004817A - Producing method of electrostatic dissipation plastic using functionalized carbon nanotube flame retardant composites - Google Patents

Abstract

The method for producing an electrostatic dispersion plastic using a functionalized carbon nanotube flame retardant composite according to the present invention is a functionalized carbon nanotube in which a carboxyl group is introduced by carrying out 80 to 99 parts by weight of a phosphorus-based compound containing no halogen and a purification and functional group introduction treatment 1 Dispersing the flame-retardant composite material containing 20 to 20 parts by weight in plastic, characterized in that the production of electrostatic dispersion plastic. In addition, the method for preparing a flame retardant composition according to the present invention is based on a patent application of the patent application No. 10-2011-0044904 to remove the amorphous carbon of the carbon nanotubes and the metal for the catalyst and to introduce a functional group, purification, functional introduction step; Mixing 80 to 99 parts by weight of a halogen-free phosphorus compound and 1 to 20 parts by weight of a carbon nanotube into which a functional group is introduced through the purification process; And chopping and suspending the mixture by ultrasonic waves, characterized in that the method is prepared by dispersing in a plastic using a functionalized carbon nanotube flame-retardant composite prepared.
By using the flame retardant composition of the present invention, it is possible to produce a plastic exhibiting electrostatic dispersibility while providing excellent flame retardancy to the resin while maintaining stable physical properties of the final resin without using harmful halogen. In addition, carbon nanotubes, which have excellent mechanical properties and are not easy to disperse, can be obtained more easily than compounding and dispersing carbon nanotubes directly into resin through primary dispersion in flame retardants. To provide a process. In addition, by using the method for producing an electrostatic dispersion plastic of the present invention, it is possible to effectively produce excellent plastics exhibiting electrostatic dispersion as described above.

Description

Producing method of electrostatic dissipation plastic using functionalized carbon nanotube flame retardant composites}

The present invention relates to a method for producing an electrostatic dispersion plastic. More specifically, the present invention provides an electrostatic dispersion plastic, characterized in that it is easily dispersed in plastic using a flame-retardant composite material in which functionalized carbon nanotubes are first dispersed in a phosphorus flame retardant to produce an electrostatic dispersion plastic (ESD plastic). It relates to a manufacturing method of.

Most synthetic polymers are flammable and are likely to release toxic gases on combustion. Therefore, for a long time, efforts have been made to impart flame retardancy and nonflammability with the development of synthetic resins. In particular, flame retardant grades of synthetic resins used as exterior materials for electrical and electronic products are currently required by law in most countries.

There has been a technique of using a halogen compound such as chlorine or bromine as a flame retardant. However, since halogen compounds emit various environmental pollutants and human hazards such as dioxin and furan in case of fire, various regulations on existing halogen flame retardants have been strengthened. The demand for flame retardants of the non-halogen series is expanding. Moreover, the use of antimony lowers the thermal stability and weather resistance of the plastics, so there is a disadvantage in that the physical properties deteriorate rapidly when staying in the injection machine.

In order to compensate for the above problems, phosphorus-based flame retardants such as phosphate ester compounds are used in plastic molding, but this has a problem in that the surface of the molded product tends to be poor and the heat resistance is lowered. In particular, when left at a high temperature for a long time, the decomposed phosphate ester compound is further reduced to phosphoric acid, etc., so that the physical properties of the molded product may be drastically lowered. This change is particularly acute in the case of phosphate esters in oligomeric form. Most phosphorus compounds are liquid or have a low softening point, so when they are added to synthetic resins, they act as plasticizers or softeners. In addition, in the thermoplastic resin such as ABS, PP or PE, or the thermosetting resin such as phenol resin, UPE or epoxy, the glass transition point is lowered or moved to lower the heat deformation temperature or heat resistance. Therefore, when the phosphorus compound is added to the resin in order to impart flame retardancy to the resin, there is a problem that the physical properties of the resin are lowered. In particular, in products requiring high modulus and strength, it is difficult to satisfy desired physical properties as existing phosphorus compounds. Therefore, the phosphorus-based flame retardant does not effectively act to improve the flame resistance and heat resistance of the final resin. For these reasons, there is an urgent need for an effective technology for imparting flame retardancy while maintaining stable physical properties of resins without using harmful halogen compounds.

In addition, the general plastic is a non-conductor, due to the problem of generating electricity without electricity, there has been a restriction on the use of plastic because it is connected to short phenomena in electronic devices, sparks caused by static electricity in industrial sites, and even to fire in the worst case. . In industrial sites that produce electric appliances, static electricity generated in the body of workers can be restricted due to friction even on walls and floors. You can. In order to introduce electrostatic dispersion into the plastic, a method of dispersing or coating metal or silver particles or coating silver foil is used, which greatly increases the weight of the plastic or causes a large loss in cost. Will be.

Therefore, carbon nanotubes, first discovered in 1991 by S. Iijima, Japan, have superior electrical conductivity and chemical properties to conductors or semiconductors compared to other nanofillers (Ex: nanoclay, carbon black). Its excellent stability and mechanical strength make it the most efficient and economical filler in the production of electrostatic dispersion plastics. However, despite the excellent physical properties and structure, the agglomeration of carbon nanotubes acts as a big disadvantage for its application. Therefore, the technique of dispersing carbon nanotubes is the key to using carbon nanotubes in composite materials. .

For this reason, R & D is currently focusing on technology for manufacturing plastics by dispersing new carbon nanotubes at home and abroad, but it is not commercialized.

The present invention is to solve the above problems, to provide a manufacturing method for imparting flame retardancy and electrostatic stability to the resin while maintaining the stable physical properties of the final resin without using harmful halogen. It is also an object of the present invention to provide a new process for obtaining the final carbon nanotube dispersion resin much more easily than compounding and dispersing the carbon nanotubes directly on the resin.

In addition, the method for producing an electrostatic dispersion plastic according to the present invention, an object of using the excellent flame retardant composition to play the role as described above effectively.

On the other hand, prior to explaining the solution of the problem, terms used in the present specification are defined as follows.

"Functionalized carbon nanotube" means a carbon nanotube in which a carboxyl group is introduced through a process of introducing a purified functional group into a multiwall nanotube and a single wall nanotube.

"Nano composite" refers to a compound in which a nano-sized ( ^10-9 ) filler is combined with a matrix compound.

In order to achieve the above object, the electrostatic dispersion plastic using the functionalized carbon nanotube flame retardant composite of the present invention includes 80 to 99% by weight of a halogen-free phosphorus compound and 1 to 20% by weight of carbon nanotubes into which functional groups are introduced. Characterized in that the step of dispersion mixing to composite the flame-retardant composite material into the plastic.

In the flame retardant composition, the phosphorus compound is selected from the group consisting of phosphoric acid esters, oligomers of phosphoric acid esters and inorganic phosphorus compounds.

When the electrostatic dispersion plastic is produced using the functionalized CNT flame retardant composite composition of the present invention, it is possible to simultaneously impart excellent flame retardancy and electrostatic dispersibility to the resin while maintaining stable physical properties of the final resin without using harmful halogen. In addition, the electrostatic dispersion plastic manufacturing method of the present invention can add carbon nanotubes to maintain the inherent physical properties of the final resin properties and improve the strength or electrical and thermal properties, and achieve the primary dispersion of the easy carbon nanotubes in the final resin Dispersion can be achieved.

In the flame retardant composition and method for producing the functionalized carbon nanotubes, the step of complexing with a phosphorus-based flame retardant is characterized in that the functional group has been selectively introduced from the group consisting of multi-walled carbon nanotubes and single-walled carbon nanotubes. It is based on the patent (application number 10-2011-0044094).

In the flame retardant composition and method for producing the carbon nanotubes must overcome phase separation, agglomeration, low dispersibility and poor adhesion in the matrix. These causes are nano metal particles, amorphous carbon, pentagonal fullerenes, graphite, nanocarbons. This is because carbonaceous materials such as particles and carbon nanotubes have different structures. In addition, the chemical method of introducing functional groups in order to disperse carbon nanotubes in a polymer covalently has the advantage of effectively transferring the force from the polymer matrix to the carbon nanotubes, while damaging the carbon nanotubes, rather deteriorating the reinforcing effect. It can cause, but it can be seen that due to the cohesion of covalent bonds dispersibility is greatly improved. Therefore, the carbon nanotubes undergoing the purification and functional group introduction process remove carbonaceous substances of different structures and disperse the carbon nanotubes into which the functional groups are introduced by covalent bonds.

In addition to the phosphorus compound and the carbon nanotube, the flame retardant composition of the present invention may be added with an inorganic additive or a heat stabilizer according to each use.

In the present invention, the functionalized carbon nanotube flame-retardant composites developed in advance by dispersing and compounding plastics, and the results of evaluating electrostatic dispersibility are shown in Table 1 and the test procedure in Scheme 1.

Surface Resistance According to Functionalized Carbon Nanotube Content Evaluation item Assessment Methods Evaluation results 3% CNT / flame retardant 5% CNT / flame retardant Halogen content Elemental measurement 0% containing 0% containing Flammability UL-standard V-1 V-0 Surface resistance Surface Resistance Meter 2.06x107 / sq 1.75 x 10 ⁵ / sq

Scheme 1 manufactured composits and film molding

   (a) Composites pellet (b) Film

UL-94V Test Rating V-0 V-1 V-2 Digestion time after the first and second burnout of each specimen
(t1 or t2) = 10 = 30 = 30 Sum of total post-fire extinguishing times (t1 + t2) of five specimens = 50 = 250 = 250 Digestion time and flameless combustion time after the second burning of each specimen
sum of (t2 + t3) = 30 = 60 = 60 Flame fragments or lumps fall off the specimen below 300 mm
Combustibility of Cotton NO NO YES

As shown in Table 1, the electrostatic dispersion plastic according to the present invention does not contain any halogen material as a result of elemental measurement, and is measured according to the UL-standard to obtain V-1 and V-0 grades to ensure flame retardancy and to be used as a flame retardant. It has played a role. This is because PC / ABS resin without flame retardant is V-2 grade due to combustion of the cotton below, and simple phosphorus-based flame retardant additives have a total digestion time of more than 300 seconds, which makes it difficult to achieve V-1 grade. The effect of nanotubes was confirmed. In addition, the electrical resistance of the thin film film resistance of Neat PC / ABS resin was 1.0x10 ¹³ / sq to improve the electrostatic dispersion (Electrostatic dissipation) level by the addition of complete non-conductor or carbon nanotubes. This result is the level of electrostatic dispersion can be seen by the following Scheme 2.

[Scheme 2]

ESD Compounds are Electrostatic Dissipation Plastics. Electrostatic Dissipative Plastics have a resistance level of 1x10 ⁸ / sq to 1x10 ² / sq. The two samples evaluated showed the difference in flame retardancy and resistance according to the content of carbon nanotubes, and when 5% functionalized CNTs were added, the flame retardancy and positive electrodispersity characteristics of V-0 were expressed.

Therefore, it was confirmed that the primary carbon nanotube dispersion of the flame retardant was uniformly dispersed in the final polymer matrix, thereby reducing the surface resistance to the level of electrostatic dispersion and improving the flame retardancy to V-0 grade.

In addition, the phase separation in the plastic matrix uses twin-screw extruder. The most important thing is the temperature, feed rate and screw rpm of each sector. Commonly used twin extruder, temperature and rpm of each section are shown in Table 3.

Twin-screw extruder and temperature and rpm of each section Extruder Screw Pelletizer

HEATHER () #One () #2 () # 3 () #4 () # 5 () SCRW rpm HOPPER rpm 250 255 260 260 260 205 62 50

Claims (3)

A carbon nanotube-containing flame retardant composition comprising 80 to 99% by weight of a halogen-containing phosphorus compound and 1 to 20% by weight of carbon nanotubes into which a functional group is introduced by treating with purified functional group. The method of claim 1,
The phosphorus compound is a carbon nanotube-containing flame retardant composition, characterized in that selected from the group consisting of phosphate esters, phosphate ester oligomers and inorganic phosphorus compounds. 3. The method according to claim 1 or 2,
The flame retardant composition is a method of dispersing in a plastic using a carbon nanotube-containing flame retardant composition, characterized in that the phosphorus compound is nanocomposited by covalently bonded to the carbon nanotubes.