JPH03249253A - Electrically conductive spun bond sheet - Google Patents

Abstract

PURPOSE:To obtain the title sheet suitable for antistatic use of carpet, rope, etc., having excellent antistatic effects and preventing reduction in strength by partially bonding web of nonwoven fabric comprising synthetic fiber filament through thermal pressure adhesion and further attaching by a specific adhesive. CONSTITUTION:Web of synthetic fiber filament is partially bonded by thermal adhesion or linked by needle punching and further connected with an adhesive (a monomer such as ethylenic unsaturated monomer containing an electrically conductive agent such as tin is copolymerized with a monomer consisting essentially of vinyl acetate, etc.). The adhesive is attached to the sheet in such away that building-up of solid content of the adhesive in mixed state is 5-30% and the amount of the electrically conductive component in the build-up of the solid content is 1-50%. Thus, the objective sheet is prepared.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a conductive spunbond sheet used for anti-static purposes, specifically anti-static for carpets, fan belts, ropes, bags, sheets, hoses, filters, etc. This invention relates to a conductive spunbond sheet that has excellent dust-proofing, explosion-proofing, clogging prevention, and spark discharge prevention effects.

Conventional technology Spunbond sheets made of thermoplastic synthetic fibers are made by spinning filaments from a spinneret, drawing them under suction using an air sucker, etc., and then partially heat-pressing a continuous filament web that is spread and deposited on a moving mesh band. It is generally made by bonding with adhesive or interlacing with needle punch. Spunbond sheets made by this method do not take into account antistatic properties, so static electricity is generated due to friction, etc.
It was not suitable for electrical protection applications.

Problems to be Solved by the Invention By the way, in all fields, llIw due to static electricity
, disasters are attracting attention. ! Shocks caused by static electricity, clogging due to repulsion, coiling, production problems such as dirt adhesion, and explosions and fires caused by electrical discharge may occur. Recently, with the shift to IC and LSI in electronics, ICJ? ? Electrostatic discharge causes problems such as destruction of LSIs, deterioration of quality, and malfunction of electronic equipment and devices in which they are used, and this has become a problem that cannot be ignored.

The object of the present invention is to eliminate the drawbacks of the conventional spunbond sheets made of synthetic fiber continuous filament nonwoven fabrics, and to provide a spunbond sheet that is suitable for preventing static electricity damage and does not reduce its strength. .

Means for Solving the Problems In order to solve this problem, the present invention provides a nonwoven web made of synthetic fiber filaments that is partially bonded by thermo-pressure welding, has crosslinking ability, and is mixed with a conductive agent. It is bonded with an adhesive, and the amount of adhesion based on the surface shape in the mixed state of the adhesive is 5 to 30%, and 1 to 50% or more of the conductive component is adhered thereto.

The present invention will be described in detail below.The spunbond sheet of the present invention is produced by spinning synthetic fiber filaments from a spinneret, drawing them under suction using an air sucker, etc., and partially forming a continuous filament web that is opened onto a moving mesh band. These sheets are bonded by thermo-pressure welding, or by needle punching, and then bonded with a mixed adhesive, which is a mixture of adhesive and conductive agent, to give them a conductive effect. In the spunbond sheet of the present invention, the adhesive for bonding the web is one having a cross-W# function, and is an ethylene adhesive having a self-reactive group such as an N-methylol group, an N-methoxymethyl group, or an epoxy group. A vinyl copolymer copolymerized with a sexually unsaturated monomer (self-reactive monomer), such as N-methylolacrylamide or glycidyl methacrylate, is used.

In addition, crosslinking agents having carboxyl groups, amide groups, and hydroxyl groups, such as polymethylolmelamine and polymethoxymethylmelamine, are used, and ethylenically unsaturated monomers having reactive groups such as polymethylolurea ( For example, a vinyl copolymer obtained by copolymerizing reactive monomers such as acrylamide, acrylic acid, methacrylic acid, and hydroxymethyl methacrylate is used. The main monomers copolymerized with the above self-reactive monomers or reactive monomers include vinyl esters such as vinyl acetate and vinyl chloride; acrylic esters such as methyl acrylate and ethyl acrylate; Examples include methacrylic acid esters such as methyl methacrylate, ethyl methacrylate, and n-butyl methacrylate, and nitriles such as acrylonitrile and methacrylonitrile, and these may be used alone or in combination of two or more.

On the other hand, as the conductive agent used in the present invention, at least one kind of conductive metal compound such as conductive carbon black, tin, titanium, zinc, copper, or nickel is used, and the adhesive and the conductive agent are mixed. Let it be used. If a thickener is used in combination to prevent precipitation of the conductive agent, it is possible to eliminate adhesion spots. Methods for applying the mixed adhesive include an impregnation method, a kiss coating method, a foam processing method, and any method can be used. If the surface weight of the mixed adhesive is less than 5%, the tensile strength will decrease and the tear strength will increase, but the sheet texture will be stiff. In addition, if it exceeds 30%, the tensile strength increases, but the tear strength decreases, the sheet texture becomes paper-like, and the cost increases.In the present invention, the amount of adhesion on the sheet is It needs to be in the range of 5% to 30%.

Of the amount of adhesion of the mixed adhesive of the conductive spunbond sheet of the present invention, the adhesion ratio of conductive material is 1% as the amount of adhesion for the surface shape.
Otherwise, the conductive effect will not be exhibited, and in order to obtain a more stable antistatic effect, the adhesion amount is preferably 10% or more. Furthermore, if the adhesion ratio of the conductive agent exceeds 50% of the adhesion amount for the surface shape, the IIJ@ effect will not change, and the equipment will become dirty and require cleaning, reducing the operating rate. In addition, there are problems such as damage to the fibers during tufting, resulting in a decrease in mechanical properties.

The conductive spunbond sheet of the present invention is a nonwoven fabric web made of synthetic fiber filaments that is needle-punched at a needle density of 20 to 100 times/d to bond the filaments to each other, and is further strengthened with a mixed adhesive. Since the material is bonded to the material, it is possible to obtain a sheet with excellent moldability. The needle density of this needle ring is appropriately set in the range of 20 to 100 times/- depending on the shape and insertion depth of the needling needle. If the needle density is less than 20 times/d, there will be no needling effect and the pile will be uneven during molding.On the other hand, if it exceeds 100 times/d, the filament will be cut or damaged frequently. Breakage during molding is more likely to occur.

Effect: By adhering the surface of the spunbond sheet of the present invention with an adhesive mixed with a conductive agent, an antistatic effect can be exhibited. Therefore, it can exhibit an excellent antistatic effect on general carpets, fan belts, ropes, bags, sheets, hoses, filters, etc. For example, when used on automobile carpets, it can prevent static electricity damage. Furthermore, in addition to the above-mentioned antistatic effect, an effect of preventing a decrease in strength can also be obtained.

Example Next, the present invention will be specifically explained using examples.

In the examples, a commercially available acrylic adhesive was used as the adhesive, a commercially available conductive agent was used, and both were mixed to form a mixed adhesive.

Among conductivity evaluations, (1) Surface leakage resistance (Ω) is AA
Measured using the TCC method (Static Electricity Safety Guidelines Structural Standards), (2
) The human body voltage during walking was measured using the JIS-L1201 Stroll method. (3) Strong is JIS-L-10966
, 12, IA method (strip method), using a constant speed tensile tester, a 5cII x 30cm test piece was measured at a gripping interval of 20cm+ and a tensile rate of 20cm/min.

The amount of adhesion was measured using the following method.

Wm = (B-A)/Bx100 A: 50cm x 40cm+ untreated weight (g)
B: Weight after treatment of 50CII x 40Cml (g
) The intrinsic viscosity of polyester was determined using a mixed solvent of equal weights of phenol and tetrachloroethane, with a concentration of 0.5 t/1001,
Measurements were made at a temperature of 20°C.

Examples 1 to 5 and Comparative Example 1.2 Polyethylene terephthalate with an intrinsic viscosity of 0.68 was extruded from a spinneret, drawn by suction with an air sucker, and a continuous filament opened onto a moving reticular band was partially heated. After pressure contact, a mixed adhesive with a solid content of 20% was applied, and after preliminary drying (120°C x 2 minutes), curing (170°C) was applied.
0° C. for 1 minute) to produce a conductive spunbond sheet with a basis weight of 120 t/rrF. Next, this sheet was tufted using a tufting machine (manufactured by Murayama Kikai) under the following conditions: nylon BCF tuft yarn = 1500'/80', gauge = 1/8G, stitch = 8 pieces/IN, loop pile length = 5 m.

Table 1 shows the surface leakage resistance (20°C x 40% RH) of sheets with a mixed adhesive surface weight of 20% and a different mixing ratio of adhesive and conductive carbon black, and tufted sheets on the same sheets. The measurement results of human body voltage, stress at 10% elongation, and tensile strength of the sample while walking are shown. In addition, comparative example 2
The amount of carbon in the dryer is large, and the peeling off of the carbon causes the dryer to become dirty, requiring periodic cleaning, which reduces productivity.

Below margin> Examples 6 to 10 and Comparative Example 3.4 Mixing ratio of adhesive and conductive carbon black to 80/2
0, and a conductive spunbond sheet having a basis weight of 120 g/rrf was prepared in the same manner as in Example 1, except that the amount of adhesion of the mixed adhesive was changed according to the surface shape. Seat surface leakage resistance measurement results (
Table 2 shows the measurement results of the human body voltage during walking, the stress at 10% elongation, and the tensile strength of the sample tufted onto the same sheet under the same conditions as above (20°C x 40% RH). Comparative example 4
Since the mixed solid content was large, the sheet was hard and paper-like.

(space below) Example 11.12 Instead of conductive carbon black, T i 02.5n0
Same fabric weight as Example 1 except that 2 was used, 120 g/r
A conductive spunbond sheet of rr was prepared.

Table 3 shows the measurement results of the surface leakage resistance (20° C. x 40% RH) of the sheet.

Effects of the Invention As described above, the conductive spunbond sheet of the present invention can be used for carpets, fan belts, ropes, etc. to provide excellent antistatic effects, and can also prevent a decrease in strength.

Claims (1)

[Claims] 1. A nonwoven fabric web made of synthetic fiber filaments is partially bonded by thermocompression welding and is also bonded with an adhesive having crosslinking ability and mixed with a conductive agent,
The amount of solid content in the mixed state of the adhesive is 5 to 30%, and the conductive component is 1 to 50% of the amount of surface shape adhesion.
A conductive spunbond sheet characterized by having % adhesion.