JPS6183377A - conductive acrylic fiber - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to conductive acrylic fibers.

[Conventional technology]

In recent years, with the generalization of computers, the problem of electromagnetic interference has come to the fore, and conductive resins and conductive paints are attracting attention as materials for shielding electromagnetic waves.

Conventionally, conductive fillers used in conductive resins and paints are mainly metal powders and metal fibers, but they have a specific gravity of 7.
-8, which has the disadvantage that it settles when kneaded with resin or paint, making it difficult to obtain uniform electrical conductivity. To solve this drawback, conductive fillers with low specific gravity have recently been developed, such as carbon black, carbon fiber, and synthetic fibers with a diameter of 2D or more, in which a film of conductive material is formed by electroless plating. .

However, the conductive performance of carbon black and carbon fibers is inferior to that of metals, etc., and because the conductive film formed on ordinary synthetic fibers has a large fiber structure, the conductive performance must be further improved. Also, since the fiber length is large, it tends to blister when kneaded into resin etc.

[Problem that the invention seeks to solve]

As mentioned above, when a metal or the like is added to a synthetic ml, it has a low specific gravity and exhibits fairly high conductivity.

It is still not sufficient, and furthermore, because the fineness and fiber length are large, blistering tends to occur when kneading into resin, etc. In addition, in order to form a uniform coating on the fiber surface that exhibits good conductivity, the thickness of the coating must be increased, which requires a large amount of chemicals for forming the conductive coating, which not only increases the manufacturing cost. The adhesion strength of the conductive film to the base material is not necessarily sufficient, and peeling is likely to occur. Furthermore, in the conventional electroless plating method for producing fibers with conductive coatings, the residual liquid from the process contains a large amount of metal ions, which not only wastes a lot of chemicals, but also increases the cost of liquid repellent treatment. Therefore, the present inventors are currently studying to obtain conductive fibers with a fineness of 0.05d to 1.5d.
Acrylic fibers with a 5d fiber length of 065 to 6.0 days have very small fineness and fiber length, so when kneading into resin etc.
Acrylic fibers have the characteristic of not causing blistering, and acrylic fibers that have ion-exchange functional groups combine very efficiently with metal ions in metals or metal compounds, allowing ion exchange to take place. There is almost no waste in the form of residual metal ions, and it is possible to produce fibers with high conductivity by using a smaller amount of chemicals than in the past.

Moreover, productivity is high because the ion exchange reaction can be carried out quickly at room temperature. Furthermore, rather than forming a film on the surface of the fiber, a large amount of ion-exchange functional groups and a conductive substance attached to the surface layer of the fiber are bonded by electrostatic attraction, so that the surface layer of the fiber has a conductive substance. The present invention has been completed based on the discovery that the material contains the following properties, does not peel off, and has extremely good durability.

The gist of the present invention is that it has ion exchange ability, has a fineness of 0.05d to 1.5dwIil, and a fiber length of 0.51HM to 5.
．． The conductive acrylic fiber is characterized in that the surface layer of the fiber contains a conductive metal or a conductive metal compound bonded to the ion-exchange functional group of the acrylic fiber with a weight of 0 wx.

It is preferable to use water-insoluble acrylic fibers containing 0.5 mol/kg or more of acidic groups as the #& fibers having ion exchange ability to be used in carrying out the present invention.

The acidic base contained in the acrylic fiber is 0.5nIo11
If the polymer content is less than 0, the ion exchange efficiency between the acidic groups and metal ions will be low, making it difficult to efficiently produce fibers with good electrical conductivity.

On the other hand, acrylic fibers containing 0.5 mol/"l or more of acidic groups have excellent ion exchange ability, and bonding between acidic groups and metals or metal compounds occurs quickly and efficiently at room temperature, requiring fewer chemicals than conventional methods. It becomes possible to obtain fibers with good conductive performance in small amounts.

The method for introducing ion exchange functional groups into acrylic fibers is not particularly limited, and may include copolymerizing a monomer having ion exchange functional groups with acrylonitrile during polymerization, or hydrolyzing acrylic fibers to form nitrile groups t-m. Methods such as converting the acrylic fibers into acidic groups can be used, but a method in which the acrylic fibers are hydrolyzed is preferred because a large amount of acidic groups can be efficiently introduced into the surface layer of the fibers.

In addition, as the content of acidic groups contained in acrylic fiber increases, it becomes a water-soluble polymer, so Mm with a high content of acidic groups
preferably has a crosslinked structure. Considering that the fibers used in the present invention are used as additives for paints or kneaded into resins, fibers with large fineness are not preferable because they have poor mixability as fillers, and considering the ability to efficiently develop conductive performance. Ultrafine fibers of about 0.05 d to 1.5 d are suitable. Furthermore, when the fibers have a certain length and are kneaded into the resin, the conductive performance is improved, but if the fibers are not long, it becomes difficult to disperse, and the fibers become entangled with each other, causing blistering. Therefore, 碕～3. A fiber length of about 100 mm is preferable.

As the conductive substance, simple metals or metal compounds can be used, and silver, copper, copper sulfide, copper iodide, etc. are particularly suitable.

The method for incorporating the conductive substance into the surface layer of the acrylic fiber is not particularly limited, but it is preferable to use a submerged treatment, which has a good ion exchange efficiency between the large amount of ion exchange functional groups present in the surface layer of the acrylic fiber and the metal ions. Conductive acrylic fibers can be obtained by further reducing the ion-exchanged fibers using various reducing agents.

[Example〕 The present invention will be explained in further detail with reference to Examples below.

Example 1 100.9 acrylic fibers (fineness 0.1 d, cut length 05 mm) made of a copolymer of 96 parts by weight of acrylonitrile and 7 parts by weight of vinyl acetate were mixed with 100.9 parts by weight of sodium hydroxide.
g, was well dispersed in an aqueous solution 4-e in which 50 g of hydrazine hydrate was dissolved, and treated at 100 C for 4 hours, neutralized with hydrochloric acid, washed with water, and dried. The absorbed fibers are water-insoluble, and the acidic group content determined by the absorbance method is approximately 5.
mol/'If polymer. 10 g of the acrylic fiber having the above #R group 5 mol/ky was added to an aqueous solution containing 8 I copper sulfate and 59 hydroxyamine sulfate.
When treated for 15 minutes at 20p in a swamp, most of the copper ions in the solution were ion-exchanged with the acidic groups in the fibers, and the fibers changed from white to blue.

Add 1 part of sodium chloride 5I to this dispersion liquid, and add ao
After reduction treatment with C for 20 minutes, washing with water and drying were performed. The obtained copper sulfide-containing ultrafine fibers were dark green in color and had a specific resistance of 6. O
It had a good conductivity of X 10''-'Ω·Cm and a small specific gravity of about 2.

Next, when the conductive acrylic fibers were kneaded into the resin, uniform kneading was possible without causing any blistering. As a comparative example, a fineness of 2°06. When acrylic fibers having a fiber length of 5.0 mm were kneaded into a resin, it blistered and uniform conductivity could not be obtained.

Comparative Example 1 93 parts by weight of acrylonitrile (IJ) and vinyl acetate) 7
] Acrylic fiber consisting of a copolymer in the inner part (fineness 0.1
d, cut length 0.5tg) Example 1 without performing the crosslinking and hydrolysis treatment as in Example 1.
When ion exchange of copper ions was carried out under the same conditions as above, the exchange of copper ions was extremely small and the fibers remained white. Subsequently, reduction treatment was performed under the same conditions as in Example 1, followed by washing with water and drying.

The obtained sulfurized steel-containing fibers were gray in color and had a comparative resistance of 2,
Compared to the case of using the acrylic fiber having ion exchange ability of 5×10 2 Ω of the present invention, the conductive performance was three orders of magnitude lower.

Example 2 Dispersible group 5 mo subjected to the same hydrolysis treatment as in Example 1
5oIi of acrylic fibers with l/kg polypoly were dispersed in an aqueous solution 2-e in which 3oy of silver nitrate was dissolved, and 20
Ion-exchanged hydrazine hydrate 10C for 10 minutes at C
C was added and reduction treatment was performed at 20C for 10 minutes to obtain silver-containing acrylic ultrafine fibers.

The obtained fiber contains -IF-Ag,
Specific resistance is 8. It showed good conductivity of OX 10-5Ω.

Comparative Example 2 ycryl N without ion exchange functional group used in Comparative Example 1
&m (fineness (1, 1d, m slenderness 0.5m) t = Example 2
The silver-containing fiber obtained by the treatment under the same conditions as The conductive performance was low.

[Effects and Works of the Invention] As shown in the Examples and Comparative Examples, the acrylic fibers that were given ion exchange ability through hydrolysis treatment, etc., were compared with conventional synthetic M fibers with the same treatment. Under these conditions, the 2s current performance improves by more than 2 to 3 orders of magnitude.

This has the advantage that a small amount of chemicals are required to obtain the same conductive performance as the conventional method, and the cost is extremely low.

In addition, a large amount of acidic groups on the fiber surface and the conductive material combine efficiently, and the conductive substance is contained in the fiber surface layer, resulting in intermittent separation such as peeling. It also improves durability. Furthermore, ion exchange of metal ions into acidic groups occurs quickly at room temperature, and the reduction treatment time is significantly shorter than conventional methods, which is advantageous from the viewpoint of productivity. on the other hand,
Fineness: 0.05 d to 1.5 d, fiber length: 0.5 W to 5
．． When kneading into resin etc. to use 0 wa fiber,
Uniform conductive performance can be obtained without blistering, and it can be usefully used as a conductive material such as an electromagnetic shielding material.

Claims (1)

[Claims] (1) Fineness 0.05d to 1.5d with ion exchange ability
A conductive acrylic fiber, characterized in that the fiber surface layer contains a conductive metal or a conductive metal compound bonded to an ion exchange functional group of an acrylic fiber having a fiber length of 0.5 mm to 3.0 mm.