JPH0415318B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention is applicable to the manufacturing industry of electronic parts, precision electrical machinery, films, paper manufacturing, textiles, etc., the printing industry, the transportation industry, packaging paper for records, etc., or electrophotographic copying paper. This paper relates to static neutralizing Japanese paper used to prevent static electricity.

Furthermore, the present invention neutralizes static electricity that has the potential to cause serious disasters due to ignition of combustible materials,
This paper relates to static neutralizing Japanese paper useful for solving labor safety problems.

(Prior art) Static electricity is more likely to be generated in non-conducting materials such as synthetic fibers and plastics, and they are also more likely to be charged, so when the amount of charge reaches a certain limit, static electricity energy is released and the following phenomenon occurs. .

Secondary damage caused by electric shock, insulation breakdown of electronic equipment.

Quality problems, workability, and production problems due to dirt, dust absorption, and adsorption of objects.

Ignition and explosion of flammable objects due to spark discharge.

In order to prevent the static electricity damage mentioned above, it is necessary to quickly reduce the amount of static electricity generated.
It is necessary to prevent static electricity energy from accumulating on objects, which can lead to disasters and failures.

A specific method for preventing static electricity damage and imparting antistatic properties is to temporarily attach an antistatic agent to the surface of the fabric (post-processing method).

A method of coating an object with a water-absorbing substance (humidification method).

A method of leaking and grounding using a metal wire, etc.

methods have been adopted. However, none of these methods meet the requirements in terms of durability, dust adhesion, and antistatic performance.

(Problems to be Solved by the Present Invention) The purpose of the present invention is to solve the problems caused by failures and reduced efficiency caused by static electricity in various industrial fields.
To provide static electricity neutralizing paper that is extremely effective in preventing safety degradation, fire, explosion, and discomfort caused by discharged light and sound.

(Means for Solving the Problems) The object of the present invention described above is to contain 3 to 15% by weight of short carbon fibers and 20 to 70% by weight of short synthetic fibers, based on the total weight. A mixture containing wood pulp and a binder in the remainder was made using a wet paper making method.
The paper is made to a weight of 50 g/m ² or less, is manufactured without applying heat or pressure that would inhibit the protrusion of the carbon fibers, and the short carbon fibers are uniformly dispersed, with 50 tips. / ^cm2 or more protrudes from the surface of the paper, has a half-life of 5 seconds or less, and has a frictional charging voltage.
This can be achieved using static electricity neutralizing Japanese paper characterized by a voltage of 40V or less.

The unique feature of the static electricity neutralizing paper of the present invention is that, as mentioned above, it contains specific amounts of short carbon fibers, short synthetic fibers, and wood pulp, and a large number of short carbon fibers are on the paper surface. By protruding, the half-life is 5 seconds or less and the frictional charging voltage is low.
This is because it has an electrostatic property of 40V or less.

That is, in the present invention, since a large number of short carbon fibers protrude from the paper surface, corona discharge is generated from the tips of the carbon fibers to neutralize static electricity.

FIG. 1 is an explanatory diagram for explaining the static electricity neutralizing mechanism of static electricity neutralizing Japanese paper according to the present invention.

In FIG. 1, reference numeral 1 indicates static electricity neutralizing paper according to the present invention, and reference numeral 2 indicates carbon fibers protruding from the surface of the paper. Further, 3 is a charged object. Assuming that the now charged object 3 has a positive charge, the opposite negative charge is induced in the carbon fibers in the static neutralizing paper of the present invention. That is, ions are created using the electrostatic energy of the charged object 3. When the - charges collected on the static electricity neutralizing paper of the present invention move away and move towards the +-charged area, causing a corona discharge, the + and - charges combine and are neutralized, and the static electricity is safely removed. It will be removed. In reality, this phenomenon is repeated instantaneously and continuously to remove static electricity.

In the static electricity neutralizing paper of the present invention, the tips of the paper-made carbon fibers protrude above the surface of the paper by 50 or more fibers/cm ² . In addition, the protrusion length should just be such that it barely protrudes from the paper surface, preferably
A thickness of about 001 to 1.0 mm is sufficient.

In the present invention, the short fiber content of the carbon fiber is 3 to 15% by weight, but if the short fiber content of the carbon fiber is less than 3% by weight, the desired electrostatic properties cannot be obtained. %, the effect of improving the electrostatic properties is saturated and the manufacturing cost increases. The carbon fiber short fiber content is more preferably 5 to 10% by weight.

The carbon fiber short fibers used in the present invention preferably have a single fiber fineness of 1 to 5 d, a fiber length of 3 to 6 mm, and preferably have no crimp.
In addition, from the viewpoint of electrostatic properties, carbon fibers manufactured from acrylonitrile polymer fibers are more preferable.

In the present invention, the short fiber content of the synthetic fiber is 20 to 70% by weight, more preferably 40 to 50% by weight. If the short fiber content of the synthetic fibers is less than 20% by weight, the paper obtained will be hard and have reduced strength, and if it exceeds 70% by weight, paper-making properties will be reduced. In addition, the short fibers of synthetic fibers have a single fiber fineness of 1 to
5d, the fiber length is 3 to 6 mm, and preferably has no crimp. If the fiber length exceeds 6 mm or if the fibers are crimped, the fibers become entangled, resulting in poor dispersion and poor papermaking, which is not preferred.
Further, fibers having a length of less than 3 mm are not preferred because the strength of the paper decreases. Note that polyester fiber is preferable as the synthetic fiber.

The static electricity neutralizing paper of the present invention contains 3 to 15% by weight of short carbon fibers, 20 to 70% by weight of short synthetic fibers, and the balance contains wood pulp and a binder. It can be obtained by paper-making the mixture to a paper weight of 50 g/m ² or less using a pure wet paper-making method and uniformly dispersing short carbon fibers. That is, it can be obtained by floating carbon fibers, short synthetic fibers, and wood pulp in water, pouring them onto a mesh conveyor, dewatering them, and drying them with rollers. in this case,
It is important not to apply heat or pressure, or even if it is done, to avoid heating or pressure that would inhibit the protrusion of the carbon fibers. In addition, in the present invention, the basis weight (basis weight) of the paper is set to 50 g/m ² or less, which increases the chance for the tips of the carbon fibers to protrude from the surface (improves performance).
Furthermore, the subsequent handling of this paper (taping, laminating, labeling, etc.) is improved. Weight is 50
If it is thicker than g/m ² , the protrusion of the carbon fibers from the surface will decrease, and the paper will become hard and difficult to use.

Furthermore, the static electricity neutralizing paper of the present invention has a half-life of 5
seconds or less, the frictional charge voltage is 40V or less, but this half-life and frictional charge voltage were measured by the following method. <Measurement of half-life>"STATIC DECAY METER-
406C” (a measuring instrument that measures the electrostatic properties of substances,
The decay time of static electricity was measured using the following method.

Prior to the test, apply static neutralizing Japanese paper for 24 hours.
It was left at a temperature of 25°C and a humidity of 20% for an hour.

The static electricity neutralizing paper is set between the electrodes of the Faraday gauge.

Charge a voltage of 5000V to both sides of static electricity neutralizing Japanese paper.

Static neutralizing Japanese paper is fully charged up to 5000V.

Ground the static neutralizing paper and stop applying voltage.

Measure the discharge time of static neutralizing Japanese paper in units of 1/100th of a second.

Regarding static electricity neutralizing Japanese paper, from 5000V to 2500V
The decay time to (50%, half-life) was measured.

<Measurement of frictional charging voltage> STATIRON- manufactured by Nippon Shishido Electrostatic Co., Ltd.
Static neutralizing Japanese paper in M2 for 24 hours at a temperature of 25℃.
Measurements were taken after aging to 20% humidity.

The measurement conditions were to bring the static electricity neutralizing paper into contact with an object charged to 10 KV, and measure the charged voltage after 60 seconds.

The present invention will be explained in detail with reference to Examples below.

(Example 1) 5% by weight of short carbon fibers (1d x 6mm) produced from acrylonitrile polymer fibers by a conventional method, 45% by weight of short fibers of polyethylene terephthalate fiber (1d x 6mm), 35% by weight of wood pulp and binder were mixed at a ratio of 15% by weight. This mixture was further shredded through a beating machine to obtain a homogeneous mixture, and then paper with a basis weight of 25 g/m ² was produced by a wet paper making method. In this case, after dehydration in the papermaking process,
During roller drying, heating and pressure that would inhibit the protrusion of carbon fibers were not applied. The resulting paper has about 160 short carbon fibers on the surface of the paper.
cm ² protrusion, electrostatic properties have a half-life of 0 seconds, and frictional charging voltage.
33V, surface leakage resistance less than 2.5×10 ⁵ Ω, 5000
It was possible to neutralize ~18,000V of static electricity by instantaneously discharging it into the air.

(Comparative Example 1) 5% by weight of short acrylic fibers (3d x 6mm) plated with copper sulfide, 45% by weight of short fibers of polyethylene terephthalate fiber (1d x 6mm),
35% wood pulp by weight, and 15% binder by weight
mixed in the ratio of This mixture was further shredded through a beating machine to obtain a homogeneous mixture, and then paper with a basis weight of 25 g/m ² was produced by a wet paper making method. The electrostatic properties of the obtained paper were a half-life of 7 seconds, a frictional charging voltage of 51 V, and a surface leakage resistance of 3×10 ⁶ Ω, which indicated that the electrostatic neutralized paper was inferior to the paper obtained in Example 1.

(Comparative Example 2) Carbon fiber short fibers made from acrylonitrile polymer fibers were used as the core, 5% by weight of core-sheath type short fibers (1d x 6 mm) of polyethylene terephthalate on the surface, and 5% by weight of short fibers of polyethylene terephthalate fibers (1d x 6 mm). 6mm), 45% by weight, wood pulp 35% by weight,
and binder were mixed at a ratio of 15% by weight. This mixture was further shredded through a beating machine to obtain a homogeneous mixture, and then paper with a basis weight of 25 g/m ² was produced by a wet paper making method. The electrostatic properties of the resulting paper are determined by the half-life
8.6 seconds, frictional charging voltage 65V, surface leakage resistance 4.8×10 ¹⁰
Ω, and the static electricity neutralizing property was inferior to that of the paper obtained in Example 1.

(Effect of the invention) As mentioned above, the static electricity neutralizing paper of the present invention has the following characteristics:
The paper is produced by limiting the blending amount of short carbon fibers, short synthetic fibers, and wood pulp to a specific range and making the paper uniformly, so that many short carbon fibers protrude from the surface of the paper. Therefore, it has electrostatic properties with a half-life of 5 seconds or less and a frictional charging voltage of 40V or less, making it extremely useful as a static neutralizing paper for various static prevention purposes. That is,
With the above configuration, the present invention eliminates the need for grounding even though it is a paper-like material, and prevents malfunctions and efficiency reductions caused by static electricity in various industrial fields due to air discharge. It can be made into static electricity neutralizing paper that can prevent decreased safety, fire, explosion, discomfort caused by discharged light and sound, etc. The effect of the present invention is that the island component of the antistatic polymer in which carbon black is uniformly dispersed in the synthetic polymer in the metal-plated fiber such as copper sulfide and the sea component is streaked in the fiber axis direction. This cannot be achieved by using conductive fibers with a structure in which carbon is dispersed in the core, or fibers with a core-sheath double structure in which carbon is contained in the core.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram for explaining the static electricity neutralizing mechanism of static electricity neutralizing Japanese paper according to the present invention. 1... Static neutralizing Japanese paper, 2... Carbon fiber, 3...
Charged object.

Claims (1)

[Claims] 1. A mixture containing 3 to 15% by weight of short carbon fibers, 20 to 70% by weight of short synthetic fibers, and the balance containing wood pulp and a binder. Paper is made using the wet paper making method to have a basis weight of 50g/ ^m2 or less,
It is manufactured without applying heat or pressure that would inhibit the protrusion of carbon fibers, and the short carbon fibers mentioned above are uniformly dispersed, and their tips protrude from the surface of the paper at 50 or more fibers/ ^cm2 . and has a half-life of 5
A static electricity neutralizing Japanese paper characterized by a frictional charge voltage of 40 V or less in seconds or less. 2 The short carbon fibers are manufactured from acrylonitrile polymer fibers, and the short fiber fineness is 1 to 1.
5d, the fiber length is 3 to 6 mm, and the static electricity neutralizing paper according to claim 1, has no crimp.