KR102477947B1 - Sponge-forming composition for absorbing static electricity - Google Patents

Abstract

The sponge composition for absorbing static electricity of the present invention can improve the static absorbing effect and has excellent durability such as elasticity, elongation, and tear strength.
In addition, the sponge composition for absorbing static electricity of the present invention can significantly reduce the generation of dust during work, thereby improving the working environment.

Description

Sponge composition for absorbing static electricity {SPONGE-FORMING COMPOSITION FOR ABSORBING STATIC ELECTRICITY}

The present invention relates to a sponge composition for absorbing static electricity, and more particularly, to a sponge composition for absorbing static electricity that has an improved static absorption effect and at the same time has excellent various physical properties and can be used in various types of products.

Static electricity is mainly caused by an imbalance of electric charges that occurs when the surfaces of two objects with different electrical properties come into contact with each other and then separate them. In particular, a lot of static electricity occurs in a dry environment, and the workplace is no exception, and it gives unpleasant stimulation to workers. Furthermore, when static electricity is generated in an industrial site where an ignition material is disposed, such as a semiconductor process, it may spread to an explosion fire. In a hospital operating room where delicate work is required, static electricity may pose a risk to a patient's life, so static electricity absorption or prevention is becoming a very important factor.

The generally used sponge for absorbing static electricity is too hard or has poor durability, so it collapses, making it difficult to form a sponge, and there are limitations in durability such as elasticity, elongation, and tear strength of the sponge. In addition, conventional static electricity absorbing compositions mainly use fine powdered acetylene black. In this case, a large amount of dust is generated due to acetylene black, and a marking phenomenon occurs on the floor, thereby contaminating the surrounding area.

Korean Registered Patent No. 10-1232846

An object to be solved by the present invention relates to a sponge composition for absorbing static electricity that has an improved static electricity absorption effect and at the same time has excellent various physical properties and can be used in various types of products.

In order to solve the above problems, the present invention is 10 to 30% by weight of a polyolefin resin having a melt index of 10 g/min or less and a polyolefin resin having a melt index of 15 to 100 g/min 70 to 90% by weight of a mixed polymer substrate; carbon fibers with an average length of 3 mm or more; and a porous filler impregnated with an antistatic additive.

According to a preferred embodiment of the present invention, 20 to 40 parts by weight of carbon fiber may be included based on 100 parts by weight of the polymer.

According to a preferred embodiment of the present invention, the porous filler is impregnated with an antistatic additive, and may contain 20 to 90 parts by weight of the antistatic additive based on 100 parts by weight of the porous filler.

According to a preferred embodiment of the present invention, 5 to 10 parts by weight of an additive based on 100 parts by weight of the polymer substrate is further included, and the additive may be at least one selected from the group consisting of zinc oxide, stearic acid, and polyethylene glycol. there is.

According to a preferred embodiment of the present invention, a filler, a peroxide-based crosslinking agent and a foaming agent may be further included.

According to a preferred embodiment of the present invention, the polyolefin resin is ethylene vinyl acetate (EVA), ethylene butyl acrylate (Ethylene Butylacrylate, EBA), ethylene methyl acrylate (Ethylene Methylacrylate, EMA), ethylene ethyl Acrylate (Ethylene Ethylacrylate, EEA), Ethylene Methylmethacrylate (EMMA), Ethylene Butene Copolymer (EB-Co), Ethylene Octene Copolymer (EO-Co), It may be at least one selected from the group consisting of low density polyethylene (LDPE), high density polyethylene (HDPE), and maleic anhydride grafted polyolefin (MAH-g).

According to a preferred embodiment of the present invention, at least one of a low molecular weight additive and a conductive polymer may be used as the antistatic additive.

According to a preferred embodiment of the present invention, the porous filler may have a porosity of 0.5 to 2.0 cc/g.

The sponge composition for absorbing static electricity of the present invention can improve the static absorbing effect and has excellent durability.

In addition, the sponge composition for absorbing static electricity of the present invention can significantly reduce the generation of dust during work, thereby improving the working environment.

1a to 1f are external images of foam specimens according to Examples 1 to 6 of the present invention, respectively.
2a to 2c are external images of foam specimens according to Comparative Examples 1 to 3 of the present invention, respectively.

Hereinafter, with reference to the accompanying drawings, an embodiment of the present invention will be described in detail so that those skilled in the art can easily carry out the present invention.

As described above, the conventional sponge composition for absorbing static electricity is too hard or has poor durability and collapses, making it difficult to form a sponge and having poor durability such as elasticity, elongation, and tear strength of the sponge. In addition, in the past, acetylene black of fine powder was mainly used, but in this case, a large amount of dust is generated due to acetylene black, and a marking phenomenon occurs on the floor, thereby contaminating the surrounding area.

Accordingly, in the present invention, 10 to 30% by weight of a polyolefin resin having a melt index of 10 g/min or less and 70 to 90% by weight of a polyolefin resin having a melt index of 15 to 100 g/min are mixed polymer substrate; carbon fibers with an average length of 3 mm or more; and a porous filler impregnated with an antistatic additive.

Accordingly, according to the present invention, it is possible to easily form a sponge having an excellent static electricity absorption effect and excellent various physical properties, and it is possible to significantly reduce dust generated during work by using carbon fibers, thereby improving a working environment. In addition, by including a porous filler impregnated with an antistatic additive, migration and blooming of the antistatic additive can be suppressed while the effect of removing static electricity by carbon fiber can be maximized.

First, the polymer substrate will be described.

The polymer substrate is a mixture of 10 to 30% by weight of a polyolefin resin having a melt index of 10 g/min or less and 70 to 90% by weight of a polyolefin resin having a melt index of 15 to 100 g/min. use that

The melt index means the melt flowability of a resin at a constant load and a constant temperature. As described above, the present invention forms a polymer substrate by mixing two types of polymer resins having different melt indices. Accordingly, in the case of forming a sponge using the sponge composition of the present invention, the expansion is performed at an appropriate level, and the sponge can be easily formed without difficulties such as sinking of the sponge during the forming process. In addition, it is possible to form a sponge with excellent physical properties such as elasticity, elongation, and tear strength.

Specifically, the polyolefin-based resin has a melt index of 10 g/min or less. It may be preferably 0.2 to 10 g/min, and more preferably 1 to 5 g/min. In addition, the polyolefin resin has a melt index of 15 to 100 g/min. It may be preferably 20 to 50 g/min, more preferably 30 to 100 g/min.

If the melt index of the resin exceeds the above range, the melt flowability of the composition is too high, and a problem in that the molded article sinks during the foaming process may occur, and if the melt index of the resin is less than the above range, the composition Melt flowability is too low, and a problem in which it is difficult to manufacture a molded product having a certain size may occur.

In addition, as described above, the present invention uses a polymer substrate in which a polyolefin resin having a melt index of 10 g/min or less and a polyolefin resin having a melt index of 15 to 100 g/min are mixed It has to be done.

In this way, when a sponge is formed using the sponge composition of the present invention by mixing resins having melt indices in different ranges from each other to form a polymer substrate, expansion is performed at an appropriate level, thereby facilitating an expanded molding having a certain size. In addition, the sponge can be easily formed without difficulties such as sinking of the sponge during the sponge formation process. In addition, at the same time, it is possible to form a sponge having excellent mechanical strength such as elasticity, elongation, and tear strength.

On the other hand, the polymer substrate contains 10 to 30% by weight of a polyolefin resin having a melt index of 10 g/min or less and 70 to 90% by weight of a polyolefin resin having a melt index of 15 to 100 g/min. It is formed by mixing, and preferably, 15 to 25% by weight of the polyolefin-based high viscosity resin and 75 to 85% by weight of the low-viscosity polyolefinic resin may be mixed.

When the high-viscosity polyolefin-based resin and the low-viscosity polyolefin-based resin are mixed in the above content range, the melt index of the composition is improved to an appropriate level. This means that the flow of the composition is smooth, and the composition moves evenly to all areas in the mold before crosslinking is performed, reducing errors during sponge molding. In addition, the durability of the sponge can be further improved by adding the flexibility of the low-viscosity polyolefin to the excellent impact resistance of the high-viscosity polyolefin.

According to a preferred embodiment of the present invention, the polyolefin resin is ethylene vinyl acetate (EVA), ethylene butyl acrylate (Ethylene Butylacrylate, EBA), ethylene methyl acrylate (Ethylene Methylacrylate, EMA), ethylene ethyl Acrylate (Ethylene Ethylacrylate, EEA), Ethylene Methylmethacrylate (EMMA), Ethylene Butene Copolymer (EB-Co), Ethylene Octene Copolymer (EO-Co), It may be at least one selected from the group consisting of low density polyethylene (LDPE), high density polyethylene (HDPE), and maleic anhydride grafted polyolefin (MAH-g).

In this case, the meaning of 'any one or more' may mean any one, two or more, or a combination of two or more.

Next, carbon fiber will be described.

Carbon fiber means a fibrous carbon material having a mass content of carbon element of 90% by weight or more. Carbon fiber is a material that combines the characteristics of carbon materials and the characteristics of fibers. Heat resistance, chemical stability, electrical and thermal conductivity, dimensional stability due to low thermal expansion, low density, friction and wear characteristics, X-ray permeability, electromagnetic wave shielding, biophilicity It has excellent characteristics such as flexibility and flexibility. In addition, remarkably excellent adsorption characteristics can be imparted depending on the activation conditions. The electrical conductivity of carbon fibers depends on crystallinity, and generally has an electrical resistance value of 0.5 to 0.8×10 ^-3 Ω·cm.

The average length of the carbon fibers used in the present invention should be 3 mm or more, preferably 3 to 10 mm, and more preferably 4 to 7 mm. This enables smooth compounding and uniform dispersion. If the average length of the carbon fiber is 3 mm or less, a problem in that the economic feasibility is significantly lowered compared to the effect expressed may occur.

In addition, the present invention includes 20 to 40 parts by weight of carbon fiber based on 100 parts by weight of the polymer substrate. Accordingly, the present invention has an effect of reducing dust generated during work to effectively improve the working environment and improving the static electricity absorption effect.

If the carbon fiber is included in an amount of less than 20 parts by weight, mechanical strength such as hardness, tensile strength, elongation, etc. is somewhat lowered, and it is difficult to absorb static electricity due to high resistance, and the prevention effect may be deteriorated. In addition, if the carbon fiber is included in an amount of more than 40 parts by weight, the static control performance is exceeded, and thus the weight increase effect is low, the cost is increased, and the processing time is prolonged.

Next, the porous filler impregnated with the antistatic additive will be described.

The porous filler impregnated with the antistatic additive means that the pores of the porous filler are impregnated with the antistatic additive.

When a porous filler impregnated with an antistatic additive is included, the porous filler serves as a reinforcing filler and provides space at the same time, thereby preventing migration and blooming of the antistatic additive, and maximizing the effect of carbon fiber to absorb static electricity. can be significantly improved. In addition, carbon fiber is treated as a relatively expensive material, and when a porous filler impregnated with an antistatic additive is included, the required content range of carbon fiber can be lowered, thereby improving economic feasibility.

Meanwhile, according to a preferred embodiment of the present invention, the antistatic additive may be included in an amount of 10 to 100 parts by weight based on 100 parts by weight of the porous filler. More preferably, it may be included in 20 to 90 parts by weight.

In addition, according to another preferred embodiment of the present invention, 10 to 25 parts by weight of low molecular alcohol may be included with respect to 100 parts by weight of the polymer substrate. More preferably, it may be included in 10 to 20 parts by weight, and more preferably, it may be included in 10 to 15 parts by weight. In this case, it is possible to lower the content range of the carbon fiber required to improve the static electricity absorption effect, and thus the economic feasibility can be improved.

If the antistatic additive is included in an amount less than the above range, the effect of the carbon fiber cannot be maximized, thereby reducing the antistatic effect, and as more carbon fibers must be used, economic feasibility may significantly decrease. In addition, if the antistatic additive is included in excess of the above range, migration and blooming may occur due to the antistatic additive not impregnated into the porous filler.

As the porous filler, a ceramic type filler having a porosity of 0.5 to 2.0 cc/g may be used. Through this, it can be easily dispersed in the polymer composition, so there is an effect of obtaining a uniform composition.

When the porosity is 0.5 cc/g or less, it is difficult to impregnate the antistatic additive in a sufficient amount due to an insufficient amount of impregnation, and as a result, the static control effect is insignificant. Alternatively, migration and blooming may occur due to excessive impregnation of antistatic additives. When the porosity is 2.0 cc/g or more, there is a high possibility of making the work process difficult due to excessive impregnation.

The antistatic additive means an additive for absorbing or preventing static electricity, such as an antistatic agent, and those commonly used in the art may be used. Preferably, at least one of a low molecular weight additive or a conductive polymer may be used. Examples of the low molecular weight additive include polyethylene glycol (PEG), diethylene glycol (DEG), ethylene glycol (EG), and polypropylene. Glycol (Polypropylene glycol, PPG) and the like can be used.

Through this, the effect of the carbon fiber can be maximized, and thus the content range of the carbon fiber required for absorbing static electricity can be minimized.

Optionally, the present invention may further include an additive, a filler, a peroxide-based crosslinking agent, and a foaming agent.

The present invention may further include any one or more selected from the group consisting of zinc oxide and stearic acid as an additive.

Zinc oxide can improve heat resistance and vulcanization rate, and stearic acid can improve the dispersibility of the composition.

According to a preferred embodiment of the present invention, the additive may be included in an amount of 0.1 to 10 parts by weight based on 100 parts by weight of the polymer substrate. More preferably, 0.1 to 4 parts by weight of zinc oxide and 0.1 to 2 parts by weight of stearic acid may be included based on 100 parts by weight of the polymer substrate. More preferably, 1 to 3 parts by weight of zinc oxide and 0.5 to 1.5 parts by weight of stearic acid may be included based on 100 parts by weight of the polymer substrate.

In this case, the crosslinking reaction can be maintained at an appropriate rate, so that productivity can be improved.

If the additive is less than the above range, a crosslinking reaction may be too slow, and if the additive is more than the above range, the crosslinking reaction rate is too fast and the unreacted material may be present on the surface of the specimen. A blooming phenomenon may occur.

In addition, the present invention may crosslink the sponge composition by further including a peroxide-based crosslinking agent. Peroxide-based crosslinking agents include 1.1-(t-butylperoxy)-3.3.5-trimethyl cyclohexane (TMC), n-butyl-4.4-bis-butylperoxy) Valerate (TVP), Dicumyl peroxide (DCP), 1.1'-bis(t -butyl peroxy) disoproppyl benzene (BPPB), benzoyl peroxide (BPO), t-butyl peroxy benzoate (Z), di-t-butyl peroxide (DTBP), 2.5-dimethyl-2.5-di-t-butyl peroxy hexane (25B ), 2.5-dimethyl-2.5-di-t-butyl peroxyl hexne-3 (Hexyne-3), and the like. Through this, it is possible to improve heat resistance and crosslinking density by reducing the distance between polymer molecular chains.

According to a preferred embodiment of the present invention, 0.5 to 5 parts by weight of a crosslinking agent may be further included based on 100 parts by weight of the polymer substrate. More preferably, 1 to 3 parts by weight of a crosslinking agent may be further included based on 100 parts by weight of the polymer substrate. In this case, durability and durability properties can be improved, and heat resistance can be improved.

In addition, the present invention may further include a foaming agent to prepare a foamed body. As the foaming agent, azo compounds, Oxybisbenzene sulfonyl hydrazide (OBSH), Dinitroso pentamethylene tetramine (DPT), Toluene sulfonyl hydrazide (TSH) ), toluene sulfonyl semi carbazide (PTSS), etc. may be used.

On the other hand, the present invention may further include other additives, crosslinking accelerators, crosslinking agents, etc., which are used in the field of conventional sponge compositions, if necessary. As for other additives, common additives used in the manufacture of foam, such as metal oxides, antioxidants, zinc stearate, titanium dioxide, and crosslinking aids, which are commonly used to help process characteristics and improve physical properties of foam, can be used. It is also possible to use various pigments.

Hereinafter, the present invention will be described in more detail based on examples.

Example 1

In a kneader preheated to 50 ~ 80 ℃, the raw polymer resin according to Table 1 and all additives except for the crosslinking agent, crosslinking accelerator, and foaming agent were added together and kneaded for 15 minutes at a speed of 30 rpm. Thereafter, a crosslinking agent, a crosslinking accelerator, and a foaming agent were added to the composition through a twin roll mill, dispersed and mixed for 5 minutes, and a sheet having a thickness of 3 to 3.5 mm was prepared. This was molded at a pressure of 130 kg/cm 2 with a press at 160 to 170° C. to produce a sponge having an expansion ratio of 150 to 160%.

Examples 2-6

Example 1 was performed except that the raw polymer resin, crosslinking agent, crosslinking accelerator, foaming agent and additives were used according to Table 1 below.

Comparative Examples 1 to 3

Example 1 was performed except that the raw polymer resin, crosslinking agent, crosslinking accelerator, foaming agent and additives were used according to Table 2 below.

Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 polymer resin
(parts by weight) high viscosity
EVA 10 20 20 10 20 20 low viscosity
EVA 90 80 80 0 0 0 LDPE 0 0 0 90 80 80 conductive filler
(parts by weight) carbon fiber
(6mm) 20 20 30 20 20 30 Impregnated porous filler (parts by weight) Diethylene glycol/
filler ¹⁾ 20 20 20 20 20 20 additive
(parts by weight) zinc oxide 2 2 2 2 2 2 stearic acid One One One One One One blowing agent
(parts by weight) Azo type ²⁾ 2.5 2.5 2.5 2.5 2.5 2.5 Crosslinking accelerator (parts by weight) TAC 0.5 0.5 0.5 0.5 0.5 0.5 Crosslinking agent (parts by weight) TMC ³⁾ 1.5 1.5 1.5 1.5 1.5 1.5

1) Impregnated with 30 parts by weight of diethylene glycol in 100 parts by weight of Zeosil-175

2) Azodicarbonamide

3) 1.1-(t-butylperoxy)-3.3.5-trimethyl cyclohexane

Comparative Example 1 Comparative Example 2 Comparative Example 3 polymer resin
(parts by weight) high viscosity
EVA 100 0 20 low viscosity
EVA 0 100 80 conductive filler
(parts by weight) carbon fiber
(6mm) 20 20 0 carbon fiber
(0.3mm) 0 0 10 impregnated porous filler
(parts by weight) Diethylene glycol/
filler ¹⁾ 20 20 20 additive
(parts by weight) zinc oxide 2 2 2 stearic acid One One One blowing agent
(parts by weight) Azo type ²⁾ 2.5 2.5 2.5 Crosslinking accelerator (parts by weight) TAC 0.5 0.5 0.5 Crosslinking agent (parts by weight) TMC ³⁾ 1.5 1.5 1.5

1) Impregnated with 30 parts by weight of diethylene glycol in 100 parts by weight of Zeosil-175

2) Azodicarbonamide

3) 1.1-(t-butylperoxy)-3.3.5-trimethyl cyclohexane

Experimental Example 1. Resistance evaluation

The specimens of Examples 1 to 6 and Comparative Examples 1 to 3 were divided into 9 equal parts, and the resistance values of each zone were measured using the resistance measurement position of FIG. 1 and the resistance measurement method of FIG. 2 to confirm uniformity. At this time, the experimental conditions were adjusted to room temperature of 24 ℃ and humidity of 55 to 65%, and the probe distance of the resistance meter was maintained at 3 cm. The resulting values are shown in Tables 3 and 4 below.

resistance measurement location Resistance (Ω, temperature 23℃/humidity 40%) Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 One 4×10 ⁸ 8×10 ⁷ 4×10 ⁶ 2×10 ⁸ 6×10 ⁷ 4×10 ⁶ 2 8×10 ⁷ 1×10 ⁸ 5×10 ⁷ 6×10 ⁸ 2×10 ⁷ 3×10 ⁶ 3 5×10 ⁷ 8×10 ⁷ 3×10 ⁷ 5×10 ⁸ 4×10 ⁶ 6×10 ⁶ 4 6×10 ⁷ 1×10 ⁸ 4×10 ⁶ 3×10 ⁸ 6×10 ⁷ 3×10 ⁶ 5 5×10 ⁸ 1×10 ⁸ 1×10 ⁶ 6×10 ⁷ 2×10 ⁸ 2×10 ⁷ 6 1×10 ⁸ 1×10 ⁸ 7×10 ⁶ 7×10 ⁷ 4×10 ⁶ 4×10 ⁶ 7 5×10 ⁷ 8×10 ⁷ 3×10 ⁶ 5×10 ⁷ 3×10 ⁷ 5×10 ⁶ 8 2×10 ⁸ 1×10 ⁸ 2×10 ⁷ 9×10 ⁷ 3×10 ⁸ 6×10 ⁶ 9 6×10 ⁷ 1×10 ⁸ 6×10 ⁶ 7×10 ⁷ 3×10 ⁸ 6×10 ⁶

resistance measurement location Resistance (Ω, temperature 23℃/humidity 40%) Comparative Example 1 ^One) Comparative Example 2 ^One) Comparative Example 3 One - - > 1×10 ¹⁰ 2 - - > 1×10 ¹⁰ 3 - - > 1×10 ¹⁰ 4 - - > 1×10 ¹⁰ 5 - - > 1×10 ¹⁰ 6 - - > 1×10 ¹⁰

1) Resistance not measured because molding is not possible

Experimental Example 2. Appearance evaluation

The appearances of the specimens of Examples 1 to 6 and Comparative Examples 1 to 3 were observed and evaluated according to the following criteria. The resulting values are shown in Table 5 below. In this regard, FIGS. 1A to 1F are external images of foam specimens according to Examples 1 to 6 of the present invention, respectively, and FIGS. 2A to 2C are foam specimens according to Comparative Examples 1 to 3 of the present invention, respectively. This is an exterior image.

(No damage such as twisting or surface open cell occurrence: ◎, twisting, surface open cell occurrence, etc. 1 or more damages: Δ, twisting, surface open cell occurrence, etc. 1 or more damages and molding is not possible : ×)

appearance observation Example 1 ◎ Example 2 ◎ Example 3 ◎ Example 4 ◎ Example 5 ◎ Example 6 ◎ Comparative Example 1 × Comparative Example 2 × Comparative Example 3 △

Claims (8)

A polymer substrate in which 10 to 30% by weight of a polyolefin resin having a melt index of 10 g/min or less and 70 to 90% by weight of a polyolefin resin having a melt index of 15 to 100 g/min are mixed;
Carbon fibers having an average length of 3 mm or more; and
A sponge composition for absorbing static electricity comprising a porous filler impregnated with an antistatic additive.
According to claim 1,
A sponge composition for absorbing static electricity, characterized in that it comprises 20 to 40 parts by weight of carbon fiber based on 100 parts by weight of the polymer.
According to claim 1,
The porous filler is impregnated with an antistatic additive,
A sponge composition for absorbing static electricity, characterized in that it contains 20 to 90 parts by weight of an antistatic additive based on 100 parts by weight of the porous filler.
According to claim 1,
The sponge composition for absorbing static electricity, further comprising 5 to 10 parts by weight of an additive based on 100 parts by weight of the polymer substrate, wherein the additive is at least one selected from the group consisting of zinc oxide, stearic acid, and polyethylene glycol.
According to claim 1,
A sponge composition for absorbing static electricity, further comprising a filler, a peroxide-based crosslinking agent, and a foaming agent.
According to claim 1,
The polyolefin-based resin is ethylene vinylacetate (EVA), ethylene butylacrylate (EBA), ethylene methylacrylate (EMA), ethylene ethylacrylate (EEA), ethylene Methyl methacrylate (Ethylene Methylmethacrylate, EMMA), Ethylene Butene Copolymer (EB-Co), Ethylene Octene Copolymer (EO-Co), Low Density Polyethylene (LDPE), A sponge composition for absorbing static electricity, characterized in that it is at least one selected from the group consisting of high density polyethylene (HDPE) and maleic anhydride grafted polyolefin (MAH-g).
According to claim 1,
The antistatic additive is a sponge composition for absorbing static electricity, characterized in that at least one of a low molecular weight additive or a conductive polymer is used.
According to claim 1,
The porous filler is a sponge composition for absorbing static electricity, characterized in that the porosity is 0.5 ~ 2.0cc / g.

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