JPH054215B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a conductive floor sheet that can be freely colored and has sufficient antistatic performance. [Prior Art] A measure to prevent static electricity from forming on rubber or plastic molded products is to lower the electrical resistance of the molded product and quickly ground and dissipate static electricity generated by friction. The following methods have been known to lower the electrical resistance of rubber or plastic. (1) Adding highly conductive metal powder or fibers such as silver, copper, stainless steel, or nickel to rubber or plastic; (2) Adding carbon black or carbon fiber to rubber or plastic; (3) Rubber. Another method is to add a surfactant called an antistatic agent or something similar to the plastic. [Problems to be Solved by the Invention] Although the method (1) is very effective in preventing electrostatic charging, it cannot be colored in any desired color and is limited to metallic colors. Moreover, it is very expensive and lacks economic efficiency. Furthermore, it is desirable that the electrical resistance of the molded product be within a certain range to eliminate the risk of electric shock due to low-voltage electricity, but it is difficult to stably manufacture such a product using metal powder or metal fiber. is extremely difficult. In method (2), carbon black is often used as an inexpensive conductivity imparting agent, but it has the disadvantage that the hue is limited to black. Further, even with this method, it is difficult to industrially and stably produce molded products that are free from the risk of electric shock due to low voltage electricity. Although method (3) has the advantage of being able to be colored freely, it incorporates a surfactant that has poor compatibility with rubber and plastic and easily absorbs moisture, and bleeds onto the surface to lower surface resistance and reduce static electricity. It is obtained by letting ions escape from the surface, and relies on surface resistance, which is an electrical resistance that is easily affected by environmental conditions, and lacks stability in antistatic performance.
In particular, the antistatic effect will be considerably reduced in a low humidity environment. Moreover, the duration of antistatic performance is short. On the other hand, in recent years, factories for semiconductor parts such as ICs and LSIs and electronic equipment factories have started to use OA to prevent production failures due to the adsorption of dust and particles in micron and submicron levels due to the generation of static electricity.
The use of conductive floors in rooms and the like is being considered to prevent computer malfunctions and circuit damage caused by static electricity. In this case, it is preferable to use a sheet obtained by method (3), which can be freely colored from an aesthetic point of view, but there are concerns about its antistatic performance. The present invention has been made based on the above,
The object of the present invention is to provide a conductive floor sheet that can be colored in any color and exhibits excellent antistatic performance. [Means for solving the problems] The conductive floor sheet of the present invention has a volume resistivity of 10 ¹²
Volume resistivity is 10 ⁸ Ω− for polymer components below Ω−cm.
A conductive colored sheet made of a resin composition containing a plasticizer and a colorant of less than cm, and a resin made of rubber or plastic containing at least one of carbon black, carbon fiber, metal powder, and metal fiber. It is characterized in that it is formed by laminating a conductive sheet having a lower volume resistivity than the conductive colored sheet made of the composition. If the volume resistivity of either the polymer component or the plasticizer exceeds the specified value above, it will be difficult to achieve the desired volume resistivity while maintaining the mechanical properties necessary for a floor sheet, which is an object of the present invention. cannot be achieved. A sheet (surface) obtained from a composition whose main components are a polymer component with a volume resistivity of 10 ¹² Ω-cm or less and a plasticizer with a volume resistivity of 10 ⁸ Ω-cm or less has a volume resistivity of 10 Ω-cm or less. By laminating sheets (on the back side) with a small resistance, the static electricity charged on the front surface can be effectively leaked to the back side sheet and grounded, resulting in excellent antistatic performance. In the present invention, the polymer component having a volume resistivity of 10 ¹² Ω-cm or less includes homopolymers, copolymers,
It may be either a grafted product or a mixture.
Examples include acrylic rubber, epichlorohydrin rubber, nitrile butadiene rubber (NBR), chloroprene rubber, mixtures of these rubbers and polyvinyl chloride, polymers in which vinyl chloride is grafted onto polyurethane, and mixtures of polyurethane and polyvinyl chloride. . Also, the volume resistivity of plasticizer is 10 ⁸ Ω−
There are no particular restrictions on other properties as long as it is less than cm, but it is desirable that it is liquid at room temperature and has little volatility. For example, cresyl diphenyl phosphate, di(2,3-dibromopropyl) 2,3-dichloropropyl phosphate, di(2-ethylhexyl) phosphate, dioctyl phosphate, triamyl phosphate, Tri(2-butoxyethyl) phosphate
ester, tri(2-chloroethyl) phosphate, tri(chloropropyl) phosphate,
Phosphate tricresyl ester, phosphate tri(2,
Phosphate esters such as 3-dibromopropyl) ester, tri(dichloropropyl) phosphate, glycol fatty acid esters such as diethylene glycol dicaproate, triethylene glycol dicaproate, phthalic acid and triethylene glycol monocaproate ester Examples include esters where one side of the glycol is a fatty acid and the other side is an aromatic carboxylic acid. In addition, the various plasticizers listed above
It may be a plasticizer with 0.005-2% electrolyte added. As the electrolyte, it is preferable to use an electrolyte that is resistant to deterioration and is chemically stable, such as lithium chloride or sodium chloride. The amount of plasticizer added to the polymer component is not particularly limited as long as the desired volume resistivity can be obtained.
The amount is preferably in the range of 5 to 100 parts by weight per 100 parts by weight of the polymer component. If it is less than 5 parts by weight, it will be difficult to obtain the desired volume resistivity, and if it is about 100 parts by weight, the volume resistivity will be almost saturated, and even if more than this is added, there will be almost no change in the volume resistivity, and the compatibility will be reduced. lead to deterioration of mechanical properties. In addition to the above ingredients, of course, there are plasticizers such as DOP, and other additives such as stabilizers, antioxidants, crosslinking agents, vulcanizing agents, vulcanizing aids, lubricants, processing aids, flame retardants, and fillers. , colorants, ultraviolet absorbers, etc. can be used as appropriate, and the composition can be formulated without causing any practical problems. In this way, a conductive colored sheet obtained by adding a desired coloring agent to the above-mentioned ingredients and molding it into a sheet is laminated with a conductive sheet having a smaller volume resistivity to form a conductive floor sheet. . Examples of the conductive sheet include sheets formed from rubber or plastic mixed with carbon black, carbon fibers, metal powder, metal fibers, etc. [Example] Example 1 Conductive colored sheet ○ Polymer obtained by grafting vinyl chloride onto polyurethane (vinyl chloride graft amount 70%, volume resistivity
9.0×10 ¹¹ Ω-cm) 100 parts by weight ○ Tri(2-butoxyethyl) phosphate ester (volume resistivity 8.7×10 ⁶ Ω-cm) 50 parts by weight ○ Phthalocyanine green 1 part by weight Two rolls of the above ingredients heated The mixture was kneaded and formed into a sheet with a thickness of 0.5 mm using the press described above. The volume resistivity of this sheet was 7.8×10 ⁸ Ω-cm. The volume resistivity, including the following examples, was measured based on the Japan Rubber Association standard SRIS2304 and its commentary. Conductive sheet ○ Polyvinyl chloride resin 100 parts by weight ○ Dioctyl phthalate 70 parts by weight ○ Carbon black 80 parts by weight ○ Stabilizer, etc. 5 parts by weight The above ingredients were kneaded with two electric heated rolls, and the above press was used to form a 2.5 mm sheet. It was formed into a thick sheet. The volume resistivity of this sheet was 3×10 ² Ω-cm. A colored conductive sheet and a conductive sheet were laminated using the above-mentioned press to produce a floor sheet with a colored surface as shown in FIG. 1. In FIG. 1, 1 is a conductive colored sheet, and 2 is a conductive sheet. Example 2 Conductive colored sheet ○ Mixture of poepichlorohydrin rubber and polyvinyl chloride (epichlorohydrin rubber: polyvinyl chloride = 50:50, volume resistivity 8.5×10 ¹¹ Ω−
cm) 100 parts by weight ○ Plasticizer represented by the chemical formula below (volume resistivity
4.5×10 ⁶ Ω-cm) 50 parts by weight ○ Phthalocyanine Green 1 part by weight The above ingredients were kneaded using two electrically heated rolls and formed into a sheet with a thickness of 0.5 mm using the above press. The volume resistivity of this sheet was 5.1×10 ⁸ Ω-cm. The above electroconductive colored sheet and the electroconductive sheet used in Example 1 were laminated using a steam press to produce a floor sheet with a colored surface as shown in FIG. 1. Comparative example Conductive colored sheet ○ Polyvinyl chloride resin (volume resistivity 5.0×10 ¹⁵
Ω-cm) 100 parts by weight ○ Dioctyl phthalate (volume resistivity 1.3×10 ¹³
Ω-cm) 50 parts by weight ○ Nonionic antistatic agent (Resistant 141 manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) 2 parts by weight ○ Stabilizers, etc. 6 parts by weight ○ Phthalocyanine green 1 part by weight The above ingredients were heated using two rolls of electric heat. The mixture was kneaded and formed into a sheet with a thickness of 0.5 mm using the press described above. The volume resistivity of this sheet was 5.6×10 ¹⁴ Ω-cm. The above electroconductive colored sheet and the electroconductive sheet used in Example 1 were laminated using a steam press to produce a floor sheet with a colored surface as shown in FIG. 1. Table 1 shows the results of measuring the electrical resistance of the conductive floor sheets of Examples 1 and 2 and Comparative Example. To measure the electrical resistance, as shown in Figure 2, voltage is applied to the copper plate 4 in contact with the conductive sheet 2 using the DC power supply 5, and the current flowing through the 60 mmΦ electrode 3 is measured, and according to Ohm's law, I asked for it. Note that 6 is a voltmeter and 7 is an ammeter.

[Table] The electrical resistance of Examples 1 and 2 is significantly lower than that of Comparative Example, indicating that they have excellent antistatic performance. Examples 3 to 7 In accordance with the compounding ratios shown in each example in Table 2, the compounds were kneaded using two electrically heated rolls and molded using a high-pressure steam press to produce sheets with a thickness of 1 mm. The results of measuring the volume resistivity of this sheet are also shown in the lower column.

【table】

[Table] The volume resistivity of the sheets of each example is almost the same as the colored conductive sheets of Examples 1 and 2, and by laminating these and the conductive sheets used in the above examples, excellent antistatic performance can be achieved. It can be seen that this is achieved. [Effects of the Invention] As explained above, according to the present invention, it is possible to realize a conductive floor sheet that can be colored in any color and has excellent antistatic performance.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of one embodiment of the conductive floor sheet of the present invention, and FIG. 2 is an explanatory diagram of a method for measuring the electrical resistance of the conductive floor sheet. 1... Conductive colored sheet, 2... Conductive sheet.

Claims (1)

[Claims] 1. A conductive colored sheet made of a resin composition made of a polymer component with a volume resistivity of 10 ¹² Ω-cm or less containing a plasticizer and a colorant with a volume resistivity of 10 ⁸ Ω-cm or less, and rubber or plastic. and a conductive sheet having a volume resistivity lower than that of the conductive colored sheet made of a resin composition containing at least one of carbon black, carbon fiber, metal powder, and metal fiber. A conductive floor sheet featuring: