JP2001525447A - Method for producing antistatic resin composition and antistatic resin composition obtained by the method - Google Patents

Abstract

  (57) [Summary] In the present invention, a mixture of an alkali metal salt of alkyl sulfonic acid and a polyalkylene glycol is mixed and stirred to obtain a liquid mixture of an antistatic agent, which is extruded in an appropriate amount to be a homogeneous mixture with a molten resin. Provided is a method for producing an antistatic resin composition, comprising supplying and continuously extruding. The present invention also includes the use of the antistatic resin composition prepared by this method and the composition as a masterbatch.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001] The present invention relates to antistatic resin composition obtained by the production method and the method of the antistatic resin composition. In particular, the present invention provides a mixture of an anionic antistatic agent, such as, for example, an alkylsulfonic acid alkali metal salt, and a nonionic antistatic agent, such as a polyalkylene glycol, including, for example, polyethylene glycol.
Stir to obtain a liquid mixture of the antistatic agent, then feed the liquid mixture to the extruder in an amount appropriate to mix uniformly with a molten resin such as PMMA (polymethyl methacrylate), and continuously The present invention relates to a method for producing an antistatic resin composition which includes extruding into an antistatic resin composition; and an antistatic resin composition produced thereby.

[0002] In the background art generally plastic (synthetic resin), it its light weight, not only luxury color and good quality, because of its excellent insulating properties, is used in the manufacture of various articles You. However, the insulating properties of plastic sometimes cause the generation of static electricity which is an obstacle to using plastic in the manufacture of certain products. Although the reason for the generation of static electricity in plastics is not clearly understood, static electricity generally occurs due to surface contact such as friction, and in particular, insulating materials such as plastic are easily charged by friction. It is known.

[0003] The phenomenon of static electricity shortens the life of electrical / electronic products and poses a hazard to workers and workplaces. Therefore, development of a new plastic material in which generation of static electricity is prevented or reduced is desired. Conventionally, the following three methods have been proposed for suppressing the generation of static electricity in plastic. That is, spray a solution of antistatic agent on plastic products,
Or a surface coating method for coating the surface of a plastic product by immersing the plastic product in the solution; a melt mixing method in which the plastic material is melt-mixed with an antistatic agent; and a copolymer or graft in which a hydrophilic monomer is copolymerized with a resin. Is a copolymerization method.

[0004] The surface coating method is advantageous in that the antistatic property can be easily imparted to the resin, and the method of imparting the antistatic property is advantageous in that it is simple. However, this method is not suitable for large products. When it is necessary to remove it, it is disadvantageous in that it requires a large immersion bath and is difficult.

[0005] The copolymerization method can semi-permanently impart antistatic properties to a resin, and can be used for producing an antistatic article only by molding an antistatic resin composition. However, this method is disadvantageous in that it is difficult to manufacture various articles for various applications. Further, since the heat resistance of the antistatic resin composition is low, the product can be manufactured by injection molding, but it is difficult to manufacture by extrusion.

[0006] Melt-mixing methods have good flexibility, but it is very difficult to find optimal operating conditions such as operating temperature, compressibility, resin shape, antistatic agent, and compatibility. is there. Nevertheless, melt mixing is now commonly used and the method of the present invention is based on melt mixing. In the melt mixing method, the resin is melt mixed with an antistatic agent and extruded at a temperature between 210 ° C and 250 ° C or injected at a temperature between 190 ° C and 210 ° C. Thus, the antistatic agent used in the melt mixing method should have good thermal stability, especially in the extrusion method.

As antistatic agents that can be used to eliminate static electricity or reduce its generation, it is classified into two classes, one of which is an external coating type used in surface coating methods, One is an internal compounding type used in the melt mixing method. Alternatively, antistatic agents can be classified into three classes according to their properties. It is a cationic antistatic, such as a compound containing a quaternary ammonium salt in the molecule, an anionic antistatic, such as phosphate or sulfonate, or a nonionic antistatic, such as polyalkylene glycol. .

In general, cationic antistatic agents have the most antistatic properties, but have poor thermal stability and therefore cannot be used in the melt mixing method. Nonionic antistatic agents have the best thermal stability, but have the least antistatic properties, and thus should be added to the resin in large amounts, such as 10 parts or more by weight based on the resin. And the physical properties of the antistatic resin composition and the product obtained therefrom are deteriorated. Anionic antistatic agents have a good balance between good antistatic properties and good thermal stability.

However, the cationic or nonionic antistatic agent can be obtained in liquid or powder form, while the anionic antistatic agent is generally obtained in paste or solid form. It is difficult to supply such an anionic antistatic agent quantitatively with an ordinary liquid pump or powder feeder, and it is difficult to mix it tightly with a resin in an extruder.

On the other hand, porous powder resins such as PVC (polyvinyl chloride) are in the form of powder, liquid, paste, or granules regardless of the melt viscosity and thermal stability of the resin.
It can be easily mixed with an antistatic agent and extruded. Similarly, for non-porous resins such as, for example, PE (polyethylene) or PP (polypropylene), this is typically made in the form of pellets or granules, but with relatively low melt viscosity and good thermal stability. So that the resin, powder, liquid, paste,
Alternatively, it can be easily mixed with an antistatic agent in the form of granules and extruded. However, for some non-porous resins with low thermal stability and high melt viscosity, such as PMMA (polymethyl methacrylate), mixing and extruding with an antistatic agent in the form of powder, liquid or granules But cannot be mixed well with the antistatic agent in paste or solidified form.

As described above, anionic antistatic agents are excellent in terms of antistatic performance. However, since they are mainly made in paste or solid form, it is difficult to supply the anionic antistatic agent quantitatively, and furthermore, the viscous paste sticks to the extruder wall, making it difficult to mix at a fixed ratio. Becomes Further, it is difficult to predict the mixing amount of the antistatic agent. If the anionic antistatic agent in paste or solid form is heated so that it can be used in liquid form, problems arise due to the thermal decomposition of this antistatic agent. Furthermore, the viscosity of the drug does not drop sufficiently and it cannot be delivered by a liquid pump.

In particular, sodium alkyl sulfonate, which is an anionic antistatic agent, changes its color to black by heating, and its viscosity does not sufficiently decrease. Therefore, it is almost impossible to use a sulfonate type antistatic agent such as sodium alkyl sulfonate alone. There are commercially available anionic antistatic agents that are suitably processed during or after manufacture, in liquid or powder form, and not in solidified or pasty form. However, articles made using such anionic antistatic agents in liquid or powder form do not have satisfactory antistatic performance. In addition, such commercially available anionic antistatic agents in liquid or powder form are limited in type and supply, making it difficult to produce various products according to various applications. .

[0013] Most prior art compositions having antistatic properties are made by a method in which the resin and the antistatic agent are dry blended in a mixer such as a Henshel Mixer. However, in such a method, the added antistatic agent sticks to the wall of the mixer, which makes it difficult to incorporate an accurate amount of the drug into the resin, and a non-porous resin such as PMMA is not sufficient. Can not absorb drugs. Therefore, it is difficult to apply such a method to a real product, and it is difficult to mix a large amount of an antistatic agent for preparing a master batch.

The present invention provides a non-porous anionic antistatic agent having excellent antistatic properties,
An object of the present invention is to provide a new method for producing an antistatic resin composition by melt-mixing PMMA having a relatively high melt viscosity. As already mentioned, such anionic antistatic agents are usually obtained in paste or solidified form which makes melt mixing difficult.

Surprisingly, the inventor of the present invention has found that when the anionic antistatic agent obtained in paste or solidified form is mixed with a nonionic antistatic agent which is in liquid form, it forms a liquid mixture, The mixture can be fed using a conventional liquid pump or feeder, and furthermore, the feed liquid mixture thus obtained can be fed to a PMM
It has been found that it can be uniformly melt-mixed with a non-porous resin such as A and extruded. Furthermore, according to this new method, the inventor of the present invention has found that a large amount of anionic antistatic agent can be blended into a resin by melt mixing, so that an antistatic resin composition usable as a masterbatch can be used. They also found that things could be obtained.

[0016] Disclosure of the Invention Accordingly, a first object of the present invention is to provide a process for the preparation of antistatic resin composition. In this method, an anionic antistatic agent such as an alkylsulfonic acid alkali metal salt is mixed with a nonionic antistatic agent such as a polyalkylene glycol and stirred to obtain a liquid mixture of the antistatic agent. Next, the liquid mixture is supplied to an extruder in an appropriate amount to be uniformly mixed with the molten resin,
Includes continuous extrusion. According to the present invention, the anionic antistatic agents described above, which are generally obtained in paste or solidified form, without adding any steps to bring them into liquid or powder form Used directly. Examples of anionic antistatic agents include phosphates and sulfonates, preferably alkali metal salts of alkyl sulfonic acids, more preferably sodium dodecyl sulfonate.

Examples of the above-mentioned nonionic antistatic agents include polyalkylene glycols such as polyethylene glycol and polypropylene glycol, preferably polyethylene glycol. Their molecular weight is preferably between 100 and 500.

The mixing ratio of the anionic and nonionic antistatic agents is such that they can be mixed without separation and form a liquid phase or a phase that can be pumped by a liquid pump. This ratio is generally between 1: 1 and 1: 9 by weight. Further, the liquid mixture of the anionic and nonionic antistatic agents preferably has a viscosity of about 500 cps.

There are no particular restrictions on the nature of the resins that can be used in the method of the present invention. For the purposes of the process according to the invention, commonly known non-porous resins, in particular in the form of pellets, can advantageously be used. In particular, PMMA can be used. A second object of the present invention is to provide an antistatic resin composition produced by the method of the present invention. The antistatic resin composition made in this way can contain an antistatic agent in an amount of 0.5 to 10% by weight, based on the total weight of the composition. Generally, the amount of antistatic agent in the composition is preferably about 1-3% by weight.

The antistatic resin composition of the present invention has a relatively high content of an antistatic agent, for example, 10 to 20% by weight, but can be used as a master batch. This masterbatch is then mixed or melt-blended with the antistatic agent-free resin in an appropriate ratio to give an antistatic resin composition having a relatively low antistatic agent content, e.g. . By preparing such a master batch, mass production of the antistatic resin composition becomes possible. Accordingly, a third object of the present invention is an antistatic resin composition having a relatively high antistatic agent content, which provides a method for using a masterbatch that can be made by the method of the present invention. It is to be.

Thus, the present invention solves the problems of the prior art caused by using only one type of antistatic agent. The present invention provides a synergistic antistatic effect by using a liquid mixture of both an anionic antistatic agent, such as an alkylsulfonic acid alkali metal salt, and a nonionic antistatic agent, such as polyethylene or polypropylene. give.

There is no particular limitation on the method of mixing the anionic antistatic agent and the nonionic antistatic agent. Preferably, they are mixed at a temperature of from 30C to 100C under stirring. When the temperature is lower than 30 ° C., they are not sufficiently mixed and separated, and when the temperature is higher than 100 ° C., foaming and / or coloring of the mixture occurs. As previously mentioned, as a nonionic antistatic agent, polyethylene glycol,
Particularly, polyethylene glycol having a molecular weight of 100 to 500 can be used. As the anionic antistatic agent, an alkali metal salt of alkyl sulfonic acid can be used.

In this connection, polyethylene glycol as a nonionic antistatic agent generally has better thermal stability, but has poorer antistatic performance compared to cationic or anionic antistatic agents. When used alone to provide antistatic properties,
More than 10 parts by weight of polyethylene glycol (non-ionic antistatic agent) should be added and the other type of antistatic agent used (0.2 to 2 parts by weight)
More than double. However, if such a large amount of polyethylene glycol is added to the resin, the surface of the obtained resin or product becomes slippery and its thermal stability is deteriorated.

On the other hand, an alkylsulfonic acid alkali metal salt as an anionic antistatic agent is
It has a good balance between antistatic properties and thermal stability, but is obtained in paste or solid form with high viscosity. Furthermore, alkali metal alkylsulfonates change the color of the resin to black, and thus are likely to change the color of the resin composition when used alone with PMMA, which is itself transparent. However, the present invention mixes polyethylene glycol and an alkali metal alkyl sulfonate to form a liquid mixture, introduces the liquid mixture into the extruder barrel with a liquid pump, and then applies a non-porous material such as PMMA. A novel method for continuously producing a uniform resin composition having an antistatic property which can be continuously produced by blending or mixing with a pellet or granular resin and finally extruding. According to a variant of the invention, the composition can also be used for casting.

The antistatic resin composition thus prepared exhibits an excellent antistatic effect without showing any significant deterioration in its physical properties, for example, impact strength, bending strength, elastic modulus and tensile strength. . Therefore, this antistatic resin composition is useful as a raw material for producing various articles requiring antistatic properties.

[0026] DESCRIPTION OF THE PREFERRED below best mode examples and comparative examples according to the invention for the implementation of the invention, are not intended to limit the scope of the present invention.

Examples 1-3, Comparative Examples 1-3 Preparation of resin compositions and test pieces Sodium dodecyl sulfonate as anionic antistatic agent and polyethylene glycol as nonionic antistatic agent (Mw = 400) At a weight ratio shown in Table 1 in a bath preheated to a temperature of 50 ° C to 200 ° C and stirred. When the viscosity of the mixture reaches about 500 cps, the mixture is quantitatively introduced into the extruder by a liquid pump in the ratio shown in Table 1 and mixed with 100 parts by weight of PMMA. During the introduction, the temperature of the mixture is between 80 ° C and 90 ° C to maintain the fluidity of the drug mixture.
Maintained between ° C. The mixed mixture is continuously extruded by an extruder into a sheet, a pellet, a granule, or the like.

Testing Sheets prepared by the Bravender Single Extruder T-Die were subjected to ASTM D618.
Cut according to -61 at 23 ° C and 50% RH, and cut to dimensions of 5 cm in width and 5 cm in length. Using a sheet prepared as a test piece, a surface resistance meter (Ultra Resi
Using stance Meter, Adventest Japan), measure surface resistance according to ASTM D257. The results are shown in Table 1.

[0029]

[Table 1]

Example 4 A masterbatch is prepared in the same manner as in Example 1, except that the content of the antistatic agent is 15 parts by weight based on the total weight of the antistatic resin composition. . 8.2 and 28.7 parts by weight of the masterbatch were each combined with 100 parts by weight of PM
It is mixed with MA to prepare an antistatic resin composition containing 1 and 3 parts by weight of an antistatic agent, respectively. The composition thus obtained is extruded into a sheet. The surface resistance (Ω / sqare) of this sheet is 2.0 × 10 ¹¹ and 1.1 × 10 ¹⁰ , respectively.

According utilization present invention on the industrial, antistatic resin composition having a good balance between antistatic and thermal stability, a resin such as PMMA, such as alkylsulfonic acid alkali metal salt It can be manufactured economically and simply by melt-mixing with a liquid mixture of an anionic antistatic agent and a nonionic antistatic agent such as polyethylene glycol.

[Procedural Amendment] Submission of translation of Article 34 Amendment of the Patent Cooperation Treaty

[Submission date] October 28, 1999 (1999.10.28)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction contents]

The present invention provides a non-porous anionic antistatic agent having excellent antistatic properties,
An object of the present invention is to provide a new method for producing an antistatic resin composition by melt-mixing PMMA having a relatively high melt viscosity. As already mentioned, such anionic antistatic agents are obtained in a paste or solidified form that is thermally unstable and usually makes melt mixing difficult.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0017

[Correction method] Change

[Correction contents]

Examples of the above-mentioned nonionic antistatic agents include polyalkylene glycols such as polyethylene glycol and polypropylene glycol, preferably polyethylene glycol. Their molecular weight is preferably between 100 and 500. Polyalkylene glycols of molecular weight less than 100 evaporate or evaporate upon heating . Additionally, about 700 or 800 is greater than polyalkylene glycol molecular weight, poor combination with other materials, thus antistatic agent is not be sufficiently mixed.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0023

[Correction method] Change

[Correction contents]

In this connection, polyethylene glycol as a nonionic antistatic agent is commonly used
Has better thermal stability, but is not suitable for cationic or anionic antistatic agents
The antistatic performance is inferior in comparison. When used alone to provide antistatic properties, Based on the weight of the resin to be treated, More than 10 parts by weight of polyethylene
Recall (non-ionic antistatic agent) should be added,Of the resin to be processed Based on weight, Usage of other types of antistatic agents (0.2 to 2 parts by weight)
5 times or more. However, if such a large amount of polyethylene glycol is
When added to fats, the surface of the resulting resin or product becomes slippery and its heat stability
The property is deteriorated.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] Claim 1

[Correction method] Change

[Correction contents]

──────────────────────────────────────────────────の Continuation of the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (Reference) C09K 3/16 108 C09K 3/16 108Z (71) Applicant 146-1, Ima Building, Susong-dong, Chong ro-ku, Seoul 110-140, Republic of Korea (72) Inventor Park, Chang-Dong Korea, 305-345 Daejeon, Yousung-gu, Jinson-Dong, Durae Apartments 110-1304 F-term (reference) 4F070 AA32 AA71 AB09 AC50 AC84 AE05 FA01 FA03 FB04 FB06 FC05 4J002 BG061 CH022 EV256 FD102 FD106 GQ00

Claims (8)

[Claims] 1. A liquid mixture of an antistatic agent is prepared by mixing an anionic antistatic agent such as an alkali metal alkyl sulfonate and a nonionic antistatic agent such as a polyalkylene glycol under stirring. A method for producing an antistatic resin composition, comprising supplying the mixture to an extruder in an amount suitable for uniformly mixing the molten resin with the extruded molten resin. 2. The method according to claim 1, wherein the molten resin is PMMA (polymethyl methacrylate). 3. The method according to claim 1, wherein the polyalkylene glycol is polyethylene glycol. 4. The method according to claim 1, wherein the resin is in the form of pellets. 5. The method according to claim 1, wherein the alkali metal alkylsulfonate and the polyalkylene glycol are mixed in a weight ratio of 1: 1 to 1: 8-9. 6. An antistatic resin composition prepared by the method according to any one of claims 1 to 5. 7. Use of the antistatic composition according to claim 6 as a masterbatch. 8. An antistatic composition comprising an alkali metal alkylsulfonate and a polyalkylene glycol, wherein the alkali metal alkylsulfonate and the polyalkylene glycol are mixed in a weight ratio of 1: 1 to 1: 8-9. Composition.