JPS6036486B2 - Conductive fiber with reduced black color - Google Patents

Description

[Detailed description of the invention] The present invention relates to conductive fibers with reduced black color.

More specifically, the present invention relates to a special structure of conductive fibers with reduced conductive particle color such as blackness, and relates to conductive fibers with reduced blackness composed of three or more components. There are already many patents and products related to conductive fibers.

For example, as well-known patent applications on which the present invention is based, U.S. Patent No. 3435401, U.S. Patent No. 3003223, U.S. Patent No. 370619, British Patent No. 816965, Japanese Patent Publication No. 47
-24176, Hakama Kosho 32-4196, Tokuko Sho 46-2
6799, Special Publication No. 43-16900, Special Publication No. 52-31
450, Special Publication No. 51-143723, Special Publication No. 52-10
7350, JP 53-25893, JP 51-11
830 JP-A-51-47200, JP-A-52-5302
9, JP-A-51-139922, JP-A-51-4991
9, Tokuseki Showa 51-32821.

In both of these, conductive particles such as conductive carbon particles are mixed with Poly 7 at a high rate, and the fibers are made to exist in the form of streaks using blended yarns, composite paper yarns, etc., thereby imparting conductivity to the fibers. It was something to give.

A typical example of industrially implemented fibers is the fiber used in carpets, which was published in Japanese Patent Publication No. 31450/1983. Even if a small amount of conductive carbon is mixed with a polymer, it is sufficiently black and has a high enough percentage to provide conductivity (the preferred high percentage has already been clarified in the above-mentioned materials). The fibers are black (or gray).
Therefore, in the above cited example, the composite fiber has a core-sheath structure, has a sufficiently high ratio of powder, and is further coated with a whitening agent such as titanium oxide to eliminate blackness and impart a white tinge. The preferred method is to put it in On the other hand, the more carbon-containing component layers are exposed on the surface, such as when the relationship between one component and the pond component is a bimetallic structure, a sandwich structure, or a multi-leaf structure, the more the black color tends to become stronger, and the overall blend becomes stronger. In law,
It's so black that it's no exaggeration to say it's almost black. Even though in practical use only a very small amount of black is needed to be used in other fibers, if black is mixed in, it will greatly reduce the commercial value. It is also not preferable to perform additional dyeing (overdying). To reduce this blackness, it is possible to significantly lower the ratio of the core component in the core-sheath structure (there is a limit due to conductivity), add titanium oxide etc. to the sheath component, or use polygonal (star-shaped) shapes. The black component is placed in the valley area, and the overall effect is reflected.
It seems that the limit is to erase the blackness. The present invention aims to reduce such drawbacks as much as possible and obtain fibers with higher commercial value, and aims at fibers with fewer colors inherent to conductive particles, such as blackness. The structure of the present invention aims to achieve the object by trapping the unique color of the conductive particles within the fiber, while reflecting the color of the outer layer as much as possible. Common to all composite fibers with sheath structure and laminated structure (including those with circular arcs), it is a sea-island type composite fiber consisting of three or more components,
has only one island, and the island has a core A-sheath B structure;
Component A is made of a fiber-forming polymer and contains conductive carbon mixed therein, component B and sea component C are made of fiber-forming polymers, and component B has a lower refractive index than sea component C. Conductive fiber with reduced black color.

It is in. This configuration reduces the inherent color of the conductive particles for the following reasons.

A typical example of this configuration is shown in FIG.

That is, A is a component (example) containing conductive carbon, such as nylon, polyethylene, or nylon in which polyether units having polypropylene or oxyethylene units are incorporated into the molecular chain (this is a component (example) that contains conductive carbon). conductive carbon in a high percentage of less than 50%,
At this time, the refractive index of A is represented by the refractive index of nylon itself if it is mixed with nylon. Also, when carbon is kneaded into strips,
Although it is divided into a strip component and a matrix component, it is assumed that the refractive index of the matrix component is representative. The A component was arranged so as to be covered by the B component.

Further, a component C having a higher refractive index than B is arranged so as to cover it. Whiteness improvers such as titanium oxide and kaolin (
In the present invention, it is particularly preferable to use Component A, preferably in addition to Component B. In such a case, the refractive index may be used when titanium oxide or the like is not used. In the present invention, the larger the difference in refractive index between B and C, the more preferable. Since B is covered with C, which has a higher refractive index, it prevents colors from the C layer and the outside from reaching and being absorbed by the A layer, so the color of the C layer is strong and the color of A is less noticeable. It becomes. When the C layer is dyed, the color of the dyed C layer appears stronger than the black of the carbon inside.

Of course, this also depends on the fact that layer C is located outside of layer A. To make this situation easier to understand, a model is illustrated in Figure 2. Assuming that there are three layers A, B, and C in order, R.
Due to the refractive index, a considerable amount of the light is totally reflected between the B and C layers. Therefore, the color of the C layer appears strong. In short, the C layer was separated by the B layer to prevent light from reaching the A layer and being absorbed.

For this reason, the fibers tend to look like the color of the C layer, and when A is black, the overall gray of the fibers is reduced, making the gray appear lighter (that is, whiter when not dyed). be. It goes without saying that depending on the angle of incidence of the light beam, there are some directions that do not work as shown in Figure 2.

Note that the A layer is distinguished by dotted, but this means that each A,
This is to distinguish between B and C, and does not refer to the state of particles such as carbon particles. Note that even if the main component of A = the main component of C, the refractive index condition of the present invention can be satisfied, so there is no problem. For example, when A and C are nylon-based, 1 in the present invention These are two favorable conditions.
However, in this case, A must necessarily contain conductive fine particles (additionally inserting a core without fine particles in A or making it a friend body is within the scope of the present invention. For the present purpose, it is preferable that conductive particles are not contained in C) and C as much as possible. It is preferable that C and B contain other particles such as titanium oxide for whitening and for dyeing and stretchability. A.
Even if the B component does not exist between the C and C components, if the refractive index of the A component and the C component are much smaller, more outside light will be reflected at the interface, resulting in a significant improvement in color tone. Not limited.

In reality, the effect is smaller than expected.

The reason for this is that in order to maintain conductivity, approximately 30% of conductive particles must be mixed into the A component, and as a result, the interface of the A component cannot maintain flatness and reflects external light. The proportion becomes smaller. In other words, in order to form a smooth interface between different components with different refractive indexes, it is essential to interpose the B component, which has a smaller refractive index than the C component, between the A component and the C component. In other words, the presence of the B component makes it possible to significantly improve the color tone. At first glance, the inclusion of fine particles such as titanium oxide in component B or C seems to contradict the above purpose, but the amount of these fine particles added is usually 0.1 to 5.
%, which is an order of magnitude different from the amount of conductive fine particles added. In other words,
It does not have a fatal effect on the flatness of the interface between the B and C components. (Regarding the range of possible changes and preferred configurations) Although typical examples have been explained above, once the gist of the present invention is understood, the following types of changes can be included in the present invention, although there are differences in degree. One thing should be clear.

{a' The overall fiber formation is not only circular, but also polygonal, multilobal,
This includes all known types of deformed cross-section fibers such as star and crescent shapes.

This is a scale that can be selected independently for A and B'C. Further, the size, that is, the amount of each component can be arbitrarily selected. In an extreme case, the blackness may increase, but the amount may exceed 50% of the carbon-containing component A. Each denier is 2 to 10
0 is preferable. 'b} Although to a much lesser extent, B and C do not need to completely surround A. Regardless of whether it is bimetal type (generally bonded type) or sandwich type, it includes all fibers that form a part where the principle of the present invention can be used, at least as shown in Figure 2. You can understand its principle and effects.
However, if the portion is too small, the effect will be reduced, so it is preferable that A is surrounded by at least about 1/2 of B or C. Naturally, crescent-shaped vitamels and sandwich-shaped ones are included.

In these cases, the gist of the present invention does not hold true in a specific direction and a particle color appears, but it holds true in other directions and produces an effect. Most preferably, it is a coated type.

It is preferable that A is located in the center, but it is impossible to be perfectly centered, but it is preferable that A is within a deviation of 20 to 30% in diameter. [c) A is 20% or less of the total, preferably 8 to 8%
1%, but it is preferable that B is also less than C,
Furthermore, it is preferable that the thickness of B is smaller than that of C.

'd} Even if one or more holes are made in A, or another core is inserted into A, or even if A is made into alternating layers or multiple layers, the gist of the present invention will not be lost and it is naturally included in the present invention.

'e} Each of A, B, and C may be independently polygonal, star-shaped, multilobal, circular, elliptical, modified cross-section, etc., and may be preferable for various reasons.

FIG. 1 is just one representative example. 'fl A
The preferable amount of conductive particles relative to the resin in the component and the use of conductive fibers are specifically and detailed in the above-mentioned references, and the same tendency applies to the decrease in conductivity due to stretching.

The fibers according to the present invention are preferably co-spun and mixed with monocomponent fibers of C or B, and the amount thereof is 1 of C or 8.
~8% is preferred. In the present invention, the preferred limitations and ranges of these references for component A extend to the present invention (therefore, the references should be referred to in full detail).

). However, the main purpose of the present invention is not to invent the conductive effect itself. [g' The present invention requires at least a three-component spinning machine, but this does not impair the effectiveness of the present invention.

Regarding a practical three-component spinning machine, the present inventors have already disclosed the technology through numerous applications, and have overcome many of the difficulties associated therewith. {h)B
Regarding the multilayers of and C and B and A.

It goes without saying that the C layer of the present invention may further include one or more B layers. At that time, special ingenuity is required for the spinneret and spinning machine. For example, A and BC
In some cases, this can also be achieved by using a two-component type three-component spinning machine, in which B and C are regarded as one polymer flow, and a multilayer flow consisting of B and C is poured into the spinneret. 'i) The fiber is
Due to stretching (molecular orientation), the refractive index differs in the stretching direction and in the direction perpendicular to the stretching direction.

It is also the basis for technology that estimates the degree of orientation by measuring birefringence. In the present invention, even if the value in use is satisfied, it is still within the range, but it is difficult to measure, and since A, B, and C are stretched by the same amount at the same time, the material polymer Relative values can be approximately compared using raw materials (for example, refractive index of film, etc.)
. The refractive index of these materials can be compared using a general refractometer, birefringence meter, transmission interference birefringence meter, etc.

Examples will be shown next, but the usefulness of the present invention is not limited or limited by the examples.

Rather, it indicates the next application and development. Example Conductive nylon 6 containing 32% conductive carbon fine particles was used as component A, nylon 12 was used as component B, nylon 6 containing 3.5% titanium oxide was used as component C, and 3
Set the spinneret for triple core sheath on the component spinning machine and make 265qo
The yarn was spun.

The ratio of A to B to C was 5 to 7 to 88, respectively. The cross-sectional shape of the entire spun fiber is similar to that shown in FIG. 1, and the spun fiber is wound vertically at a rate of 2000 threads/min, and the undrawn fiber thus wound is heated at a preheat temperature of 150 oo. The fiber was drawn 4 times to obtain a fiber of about 9 denier. This three-component fiber was expected to be quite dark gray without knowing the relationship between the refractive index, but perhaps because the nylon single wave and nylon-like material satisfy the requirements of the present invention, the gray color is extremely dark. The fibers were so white that it was hard to believe that they were thin, jet-black conductive fibers containing carbon. For confirmation and comparison, three-component spinning (with a refractive index of about 1.5) was used instead of nylon 12 (with a refractive index of about 1.4) as the B component. Rather than the accuracy of the absolute value of the refractive index, we focused on the inherent difference, and compared the results by performing spinning under the same conditions and at the same stretching ratio.

The stretching conditions for this fiber were also the same as those described above. As a polymer material, this fiber can be said to be the same nylon 6 material rather than three components. Although this two-component fiber could not be called black and looked gray, it had a much stronger black tinge than the former, that is, the fiber according to the present invention.
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[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a ternary fiber according to the present invention. FIG. 2 shows a model of each layer of a three-component polymer having different refractive indexes, and illustrates that light is easily reflected due to the difference in refractive index. Figure 1 Figure 2

Claims (1)

[Claims] 1 A sea-island type composite fiber consisting of three or more components, which has only one island, and the island has a core A-sheath B structure, component A is composed of a fiber-forming polymer, and therein A conductive fiber with reduced black color, containing conductive carbon mixed therein, wherein component B and sea component C are composed of fiber-forming polymers, and component B has a lower refractive index than sea component C.