KR100795171B1 - Manufacturing methods of conductine mc nylon and conductine mc nylon thereof - Google Patents

Abstract

A method for preparing conductive monomer casting nylons is provided to impart high electroconductivity and good mechanical strength to monomer casting nylons by adding carbon fiber powder having good electroconductivity and excellent dispersibility during an initial polymerization step. A method for preparing conductive monomer casting nylons includes the steps of: preparing a catalyst bath and a co-catalyst bath having the same volume; vacuum-drying a monomer(lactam) to a moisture content of 0.01wt% or less; charging 60-95wt% of the vacuum-dried monomer(lactam) and 5-40wt% of carbon fiber powder into the catalyst bath, thereto adding a catalyst, and stirring the admixture at a revolution speed of 500-5000 rpm for 3 minutes or more; putting the vacuum-dried monomer(lactam) having the same amount as the monomer(lactam) charged into the catalyst bath, a co-catalyst, and a dispersant/antifoaming agent into the co-catalyst bath, and mechanically mixing the admixture; heating a mixing bath to 100-120 °C; charging the monomer(lactam) mixed with a catalyst, and the monomer(lactam) mixed with a co-catalyst into the heated mixing bath, and stirring the mixture homogeneously for 4-7 minutes; heating a mold to 140-180 °C; and putting the homogenized mixture into the heated mold, and polymerizing the mixture.

Description

Manufacturing Method of Conducting MC Nylon and Conducting MC Nylon Prepared by the Method {Manufacturing Methods of Conductine MC Nylon and Conductine MC Nylon Thereof}

 The present invention relates to a monomer casting nylon (MC nylon) having a conductivity and a method for manufacturing the same, and more particularly, to reduce the amount of expensive conductive materials that impart an antistatic function and to provide an antistatic or equivalent antistatic agent. The present invention relates to a monomer cast nylon capable of imparting electrical conductivity and a method of manufacturing the same.

The monomer cast nylon has a molecular structure belonging to nylon, and is different from general molding nylon in that anion polymerization occurs in the molding mold in the presence of a basic catalyst.

When MC nylon is synthesized through an anion polymerization mechanism, nylon can be synthesized in a short time at a lower temperature than condensation polymerization. This nylon is called monomer casting nylon (weak MC nylon) because it is synthesized from monomer to casting method. Nylon has a narrow molecular weight distribution and is characterized by high crystallinity. MC nylon has excellent mechanical strength and heat resistance, and has been widely used in steel industry, automobile and shipbuilding industry, automation sector, and metal industry. However, as with other plastics, it is a nonconductor, so its use has been limited in the electrical and electronics industry and in the transportation machinery sector. Therefore, MC nylon needs to be electrically conductive so that MC nylon can be used in areas where antistatic properties are required.

Therefore, there is a continuous demand for the development of MC nylon having electrical conductivity at the same time as a semiconductor for antistatic function without significantly damaging the existing properties of MC nylon.

In response to these demands, various methods have been implemented. That is, a method of adding conductive carbon black or graphite, which is a conductive inorganic particle, has been used to synthesize conductive MC nylon.

However, when the conductive carbon black is mixed with the monomer, the conductive carbon black has a high viscosity in the form of a gel or slurry despite the low content, and adversely affects the reaction.

Meanwhile, US Pat. No. 6,265,529 reports that when graphite powder is used, unlike carbon black, a small amount of graphite is mixed with a monomer to maintain a low viscosity and synthesize the synthesized electrostatic polymer. have. However, in the case of synthesizing conductive plastic using particles of conductive shape, it is necessary to add higher loading in comparison with plastic resin, so that the conductive network is not formed in the polymer matrix. Formed to impart conductivity. In addition, when the carbon black or graphite particles in the particulate state are used in the operation section in the semiconductor process, the particles are released together with the worn plastics, which causes contamination of the clean room, and thus cannot be used. And the spherical particles lower the impact strength of the manufactured composite material. In order to make up for this drawback, it is necessary to use a conductive material in a fiber state. However, the longer the length of the fiber in the carbon fiber, when it is mixed with a low viscosity monomer such as molten lactam, poor dispersion due to agglomeration (agglomeration), etc. makes it difficult to synthesize a high conductive plastic.

Thus, in the present invention, the pulverized carbon fiber having excellent electrical conductivity and very good dispersibility is added to the initial stage of polymerization when the MC nylon is synthesized to have high electrical conductivity and excellent mechanical strength in the MC nylon of the insulator.

In the present invention, a powdery carbon fiber having excellent dispersibility is used as a conductive imparting agent, and the aspect ratio (fiber length / fiber diameter) of the carbon fiber is 50 or less.

The present invention will be described in detail as follows.

In the present invention, polymerization was carried out using a monomer well dried under a dry nitrogen stream. In the present invention, the monomer which is a raw material of MC nylon was used after the caprolactam or lauryllacactam was vacuum-dried so that the water content was 0.01 wt% or less. The manufacturing process of MC nylon is as follows.

First, the same amount of dried lactam is transferred to the catalyst tank and the promoter tank, respectively.

In the catalyst tank, 5 to 40% by weight of pulverized carbon fiber is added to 60 to 95% by weight of vacuum-dried lactam, and the catalyst is added, followed by stirring for 3 minutes or more. Solid sodium (Na) was used as a catalyst, and the pulverized carbon fiber particles had a diameter of 10 to 20 µm and an aspect ratio of 50 or less, and were dried at 100 ° C. or more for 2 hours to remove moisture before addition. . At this time, the rotation speed of the stirrer should be between 500rpm and 5000rpm and the stirring time should be more than 3 minutes and all the work should be done under dry nitrogen stream. If the stirring speed is less than 500rpm, the dispersion state is not sufficiently changed, so the stirring is performed at a sufficiently high speed and the stirring is performed for at least 3 minutes so that the carbon fibers are uniformly dispersed in the monomer mixture.

The cocatalyst and the antifoam were put in a vacuum-dried lactam in the cocatalyst tank and mechanically mixed. At this time, methylene diisocyanate (MDI) was used as a promoter, and a dispersant and an antifoaming agent were wax and silicone oil (Shin-Etsu Silicone Co., Ltd., KS-603).

Subsequently, the mixed lactams in the catalyst tank and the co-catalyst tank were added to a mixing tank heated to 80 to 120 ° C., stirred to mix well for 4 to 7 minutes, and then put into a mold heated to 140 to 180 ° C. before polymerization. When it is put into a mold heated to 140 to 180 ℃ in advance, the polymerization is performed while converting from a liquid phase to a solid phase within several ten minutes.

The conductive MC nylon prepared as described above has electrical conductivity by forming a conductive network by pulverizing carbon fibers uniformly dispersed in MC nylon. In other words, the electrical resistance of the conductive MC nylon is measured by the four-point resistivity measurement (volume resistance), the electrical conductivity is 10 ^-5 to 10 ¹ S / cm.

In the present invention, the conductive MC with improved electrical conductivity and impact strength compared to the conventional spherical carbon black or graphite by the injection of pulverized carbon fiber having excellent dispersibility in the polymerization process for the production of MC nylon having a high electrical conductivity. I could synthesize nylon.

Hereinafter, the present invention will be described in more detail with reference to Examples. This embodiment is only for illustrating the present invention in more detail, it will be apparent to those skilled in the art that the scope of the present invention is not limited to this embodiment.

EXAMPLE

30 g of well-dried lactam was added to a catalyst tank and a co-catalyst tank each having a temperature of 120 ^° C., and the mixture was stirred while continuously adding nitrogen. Into the catalyst tank, 0.06g of solid Na and 10g of powdered carbon fiber (14 μm in diameter, 0.6mm in length, aspect ratio 43) were added. In the catalyst tank, 2ml of methylene diisocyanate (MDI) and 0.5ml of silicon oil were added. Stir well. The mixed lactam in the catalyst tank and the co-catalyst tank was put in a mixing tank maintained at 110 ^° C., stirred and mixed for 5 minutes or less, and then placed in a mold preheated to 160 ° C. for 10 minutes to perform a polymerization reaction. The physical properties of the conductive MC nylon polymerized in this way were evaluated and compared with those of other general MC nylon (Table 1).

Table 1 Comparison of Properties

Here, the tensile strength is a universal testing machine (Lloyd instruments, LR 50K), the impact strength is notched Izod method using TMI Co. (Model: 43-02, pendulum: 75kgcm), according to the ASTM method Was performed. After the experiment was repeated at least 10 times, the average value was obtained except the maximum and minimum values.

characteristic How to measure unit MC nylon Carbon black additive (7%) MC nylon Powdered Carbon Fiber (14%) MC Nylon Melting point ASTM D696 ℃ 220 220 220 Heat Deflection Temperature (18.5kg / cm ² ) ASTM D648 ℃ 150 180 200 The tensile strength ASTM D638M kg / cm ² 850 800 950 Elongation ASTM D638M % 30 5 10 Impact strength ASTM D256 kgcm / cm 5.5 3.5 8.0 Volume resistance ASTM D257 Ωcm 10 ¹⁴ 10 ⁷ 10 ²

As shown in the comparison table, the MC nylon of the present invention can be seen that it is superior to other general MC nylon and carbon black addition (7%) MC nylon in all fields, such as heat deformation temperature, tensile strength, elongation, impact strength and volume resistance. .

Therefore, the present invention,

Preparing an equal volume of catalyst and promoter tanks;

Vacuum drying the monomer (lactam) so that the water content is 0.01% by weight or less;

5 to 40% by weight of the pulverized carbon fiber in 60 to 95% by weight of the vacuum-dried monomer (lactam) in the catalyst tank and adding a catalyst, followed by stirring at a rotational speed of 500 rpm to 5000 rpm for at least 3 minutes;

Mechanically mixing a vacuum-dried monomer, a promoter, and a dispersant and an antifoaming agent having the same capacity as the monomer introduced into the catalyst tank into the promoter tank;

Heating the mixing bath at 80 to 120 ° C;

Adding a monomer (lactam) mixed with a catalyst and a monomer (lactam) mixed with a cocatalyst to the mixed mixing tank heated as described above, and stirring the mixture for 4 to 7 minutes;

Heating the mold to 140-180 ° C .; And

It provides a method of producing MC nylon and MC nylon prepared by the method characterized in that it comprises a; through the step of polymerization by putting the mixture stirred well to the heated mold as described above.

As described in detail above, in the present invention, in the initial stage of the polymerization of MC nylon, high conductivity and dispersibility of powdery carbon fibers (aspect ratio, 50 or less) were added to the conductivity to add conductivity. This is an efficient and economical method compared to mixing conductive additives in a polymer melt having a very high viscosity.

Claims (5)

Preparing an equal volume of catalyst and promoter tanks; Vacuum drying the monomer (lactam) so that the water content is 0.01% by weight or less; Adding 5-40% by weight of pulverized carbon fibers to 60-95% by weight of the vacuum-dried monomer (lactam) in the catalyst tank, and adding the catalyst and stirring at a rotational speed of 500 rpm to 5000 rpm for at least 3 minutes; Mechanically mixing a vacuum-dried monomer (lactam), a promoter, a dispersant, and an antifoaming agent in an amount equal to that of the monomer (lactam) introduced into the catalyst tank; Heating the mixing bath to 100 to 120 ° C; Adding a monomer (lactam) mixed with a catalyst and a monomer (lactam) mixed with a cocatalyst to the mixed mixing tank heated as described above, and stirring the mixture for 4 to 7 minutes; Heating the mold to 140-180 ° C .; And Method of producing a conductive MC nylon, characterized in that through; the step of polymerization by putting the mixture stirred well to the heated mold as described above The method of claim 1, The monomer is a method for producing a conductive MC nylon, characterized in that the caprolactam or lauryl lactam The method of claim 1,  Particles of the pulverized carbon fiber has a diameter of 10 ~ 20㎛, the length is an aspect ratio of 50 or less and a method for producing a conductive MC nylon, characterized in that dried for 2 hours at 100 ℃ or more Conducting MC nylon, characterized in that produced by the method of claim 1. The method of claim 4  The conductive MC nylon is a conductive MC nylon, characterized in that consisting of 60 to 95% by weight monomer and 5 to 40% by weight of pulverized carbon fiber.