| PATENT NUMBER | This data is not available for free |
| PATENT GRANT DATE | November 2, 1999 |
| PATENT TITLE |
Synthetic fiber of acrylic series with animal-hair feeling |
| PATENT ABSTRACT |
A synthetic fiber of acrylic series having an excellent animal-hair feeling is provided. The surface of the fiber having unevenness, in which the center-line mean roughness of the outer periphery of the cross-section of the fiber lies within a range of 0.01 to 0.13 .mu.m, is adhered thereon with an organopolysiloxane, wherein an effect by a treatment with silicone may be obtained to a greatest extent to provide the fiber having an extremely excellent animal-hair feeling. The kinds and amounts of additives to be added to a spinning solution may be so controlled that the roughness of unevenness on the surface of the fiber lies within the above range, thereby the appearance of the fiber with or without gloss may be selected. When the roughness of the surface unevenness lies within the above range and the cross-section of the fiber is a circle, or a flat or oval section having an aspect radio of 10 or less, a fiber having an extremely excellent animal-hair feeling may be obtained. |
| PATENT INVENTORS | This data is not available for free |
| PATENT ASSIGNEE | This data is not available for free |
| PATENT FILE DATE | May 6, 1998 |
| PATENT CLAIMS |
What is claimed is: 1. A synthetic fiber of acrylic series with an animal-hair feeling, wherein said fiber has unevenness on the surface thereof and an organopolysiloxane is adhered onto the surface of said fiber in which a center-line mean roughness of the outer periphery of the cross-section of said fiber is within a range of 0.01 to 0.13 .mu.m. 2. A synthetic fiber of acrylic series according to claim 1, wherein said synthetic fiber of acrylic series is colored in solution with dye and/or pigment. 3. A synthetic fiber of acrylic series according to claim 1 or 2, wherein the cross-section of said fiber is a circle. 4. A synthetic fiber of acrylic series according to claim 1 or 2, wherein the cross-section of said fiber is a flat or an oval shape having an aspect ratio (long-/short axis) of 10 or less. |
| PATENT DESCRIPTION |
BACKGROUND OF INVENTION 1. Field of the Invention The present invention relates to a synthetic fiber of acrylic series with a durability and an extremely excellent animal-hair feeling, and more particularly to a synthetic fiber of acrylic series in which presence/non-presence of gloss in the appearance and color of fibers may be arbitrarily selected and which has an excellent animal-hair feeling. 2. Description of the Related Art Synthetic fibers of acrylic series, owing to their feeling and their easiness of finishing, have been considered hitherto as those having the most excellent animal-hair feeling among synthetic fibers, and used widely in the imitation field for imaging natural fur such as boa and seals and in the high-pile field. However, in comparison with natural furs, these synthetic fibers of acrylic series lack in the so-called sliminess in the feeling and previously a various processes have been performed to eliminate the disadvantage. Hitherto, it has been well known that silicone such as organopolysiloxane is used as a treating agent to smooth the surface of synthetic fibers and to improve the feeling into the animal-hair feeling. For example, Japanese Patent Publication No. Sho 48-17514 describes a treatment with the combinations of amino-modified silicone and polyepoxide, epoxy-modified silicone and amine compound, epoxy-modified silicone and amino-modified silicone, and the like. Further, improved processes and treating agents based on the method described above are disclosed thereafter in Japanese Patent Publications Sho 51-37996, Sho 53-19715, Sho 53-19716 and so on. However, even in the method described above, there cannot be obtained a sufficient animal-hair feeling. SUMMARY OF THE INVENTION An object of the present invention is to provide a synthetic fiber of acrylic series, in which the surface of fiber is smoothed by the silicone treatment as mentioned above, and has an excellent animal-hair feeling compared with the fibers in the prior arts. As a result of an intensive study to attain the above-mentioned object, it has been found by the present inventors that a more excellent animal-hair feeling can be obtained by restricting the degree of surface unevenness of fibers, from a knowledge that the feeling is strongly influenced by the degree of surface unevenness of fibers in the silicone treatment. Accordingly, the present invention provides a synthetic fiber of acrylic series with an animal-hair feeling which is characterized in that the synthetic fiber has an unevenness on the surface thereof, in which the center-line mean roughness of the outer periphery in the cross-section of fiber is in a range of 0.01 to 0.13 .mu.m, and the surface of the fiber is adhered with an organopolysiloxane. When the surface unevenness lies within a range of 0.01 to 0.13 .mu.m, the fiber may have an excellent animal-hair feeling irrespective of the presence/non-presence of color. In the fiber having unevenness on the surface, in which the center-line mean roughness of the outer periphery of the cross-section of the fiber is in a range of 0.01 to 0.13 .mu.m, the cross-section of the fiber may be preferably a circle or a flat or oval shape having an aspect ratio (long-/short-axis) of 10 or less. If the aspect ratio exceeds 10, a so-called toughness may not be provided, which is not preferable for the animal-hair feeling. The center-line mean roughness of the outer periphery in the cross-section of the fiber of the present invention, which defines the degree of surface unevenness of fiber, means a value obtained by the following method: A 3-dimensional surface roughness analyzer (3-dimension SEM) is used and the center-line mean roughness on the line along the outer periphery in the cross-section orthogonal to the longitudinal direction of the fiber is determined as follows: A 3-dimension SEM (ERA-8000, Erionix K.K.) is used in a magnification of 4,000 to determine the surface roughness of the fiber. The 3-dimensional uneven shape in the direction of X-, Y-and Z-axis on the surface of the fiber may be illustrated from the analysis, where the Y-axial direction is the longitudinal direction of the fiber, the X-axial direction is the direction along the outer periphery in the cross-section of the fiber among the directions orthogonal to the longitudinal direction of the fiber, and the Z-axial direction is the surface unevenness height direction orthogonal to both the longitudinal direction of the fiber and the direction along to the outer periphery in the cross-section of the fiber. In the present invention, the peripheral line in the cross-section of the fiber on the X-Z plane is defined as the line along the outer periphery in the cross-section orthogonal to the longitudinal direction of the fiber, the peripheral line being able to be taken arbitrary in any different position in the longitudinal direction of fiber. The line may be shown for example in FIGS. 1 to 8, in which the X-axis is in the direction along the outer periphery in the cross-section of the fiber orthogonal to the longitudinal direction of the fiber and the Z-axis is in the direction of unevenness height on the surface of the fiber. The center-line mean roughness means the center-line mean roughness defined in JIS-B 0601 in the line (sectional curve) shown in the figure. The length of this line is at least 10 .mu.m and the degree of the surface unevenness of the fiber is defined as a mean value of the center-line mean roughness of ten lines or more taken from the outer peripheries positioned differently in the longitudinal direction of the fiber. The center-line mean roughness (Ra) defined by JIS-B 0601 as mentioned above is the value in .mu.m obtained by the following equation when a portion having a length 1 to be determined is extracted in the direction of center-line from the roughness curve, and then the roughness curve is expressed by an equation y=f(x) and the center-line is expressed by an equation y=g(x), wherein the X-axis is the center-line of the extracted portion and the Y-axis is in the direction of longitudinal magnification: R.sub.a =1/1.intg..sup.0.sup.1 .vertline.f(x)-g(x).vertline.dx[Equation 1] In this case, the roughness curve means a curve in which the longer surface undulations than a given wave length is cut off from the cross-section curve, the center-line means a line wherein the area surrounded by the roughness curve and the line parallel to the mean line of the roughness curve is same in both sides of the center-line, and the mean line of the roughness curve means a line which is a straight or curve line having a geometrical shape of the surface to be determined in the extracted portion of the roughness curve, and is so defined that the sum of square of deviation from the line to the roughness curve may be minimum. That is to say, in the present invention, the center-line mean roughness of the fiber before silicone treatment is set to be within a range of 0.01 to 0.13 .mu.m. The center-line mean roughness of 0.01 .mu.m or less provides an undesirable sticky feeling after silicone treatment, because the surface unevenness of the fiber is too small. The mean roughness beyond 0.13 .mu.m remains still rough without animal-hair feeling after silicone treatment, because the surface roughness is too large. Preferably, it is within a range of 0.05 to 0.13 .mu.m from the viewpoint of feeling, and more preferably, within a range of 0.05 to 0.10 .mu.m, in which an extremely excellent animal-hair feeling of dry and soft touch may be obtained. In general, in the production of synthetic fibers of acrylic series, various organic additives such as vinyl acetate, cellulose acetate, polymethylmethacrylate, polystyrene and the like as well as various inorganic additives such as TiO.sub.2, Sb.sub.2 O.sub.3, Sb.sub.2 O.sub.5, and Al(OH).sub.3 are added to the spinning solution to control the whiteness, gloss and so on. The addition of pigment such as a carbon black or various dyes to the spinning solution may control the coloring and the shade of the fiber. Further, in a general wet-type spinning method, the surface unevenness of the fiber may be controlled by means of solvent concentration of coagulation bath, temperature and so on. According to the actions of these additives and spinning methods, the fibers having a surface unevenness of various degrees may be obtained and when the degree of surface unevenness is restricted within the range as mentioned above, the effect by the silicone treatment may be obtained to a great extent that a fiber having an extremely excellent animal-hair feeling is obtained. When the degree of surface unevenness of fibers lies within the range as mentioned above, any kinds of additives, pigments, dyes and spinning methods may be used in the production of the fiber. Namely, the additives and so on are so selected that the degree of surface unevenness of fiber may be within the range as mentioned above to control the whiteness, gloss and shade. The silicone treatment of the surface of the fiber having a degree of surface unevenness within the range as mentioned above may provide the fiber having an extremely excellent animal-hair feeling which is an object of the present invention. Further, in order to make the sectional shape of the fiber a circle, or a flat or oval shape having an aspect ratio of 10 or less, a nozzle of circular opening or a nozzle of flat or oval section, in which the long-/short-axis ratio is approximately 10 or less, may be used. While the fiber having a circular section, or a flat or oval section having an aspect ratio of 10 or less in the form of pile may have a suitable toughness and a preferred soft feeling. However, if the fiber in the form of pile exceeds 10 in an aspect ratio, the fiber may have no toughness and no preferred feeling. BRIEF DESCRIPTION OF THE DRAWING In the accompanying drawings FIG. 1 is a graph obtained by the analysis of a shape of a portion of the outer periphery of the cross-section of a fiber in accordance with Example 1 of the present invention by a 3-dimensional surface roughness analyzer; FIG. 2 is a graph obtained by the analysis of a shape of a portion of the outer periphery of the cross-section of a fiber in accordance with Example 2 of the present invention by the 3-dimensional surface roughness analyzer; FIG. 3 is a graph obtained by the analysis of a shape of a portion of the outer periphery of the cross-section of a fiber in accordance with Example 3 of the present invention by the 3-dimensional surface roughness analyzer; FIG. 4 is a graph obtained by the analysis of a shape of a portion of the outer periphery of the cross-section of a fiber in accordance with Example 4 of the present invention by the 3-dimensional surface roughness analyzer; FIG. 5 is a graph obtained by the analysis of a shape of a portion of the outer periphery of the cross-section of a fiber in accordance with Example 5 of the present invention by the 3-dimensional surface roughness analyzer; FIG. 6 is a graph obtained by the analysis of a shape of a portion of the outer periphery of the cross-section of a fiber in accordance with Example 6 of the present invention by the 3-dimensional surface roughness analyzer; FIG. 7 is a graph obtained by the analysis of a shape of a portion of the outer periphery of the cross-section of a fiber in accordance with Comparative Example 1 of the present invention by the 3-dimensional surface roughness analyzer; and FIG. 8 is a graph obtained by the analysis of a shape of a portion of the outer periphery of the cross-section of a fiber in accordance with Comparative Example 2 of the present invention by the 3-dimensional surface roughness analyzer. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT In order to produce a synthetic fiber of acrylic series according to the present invention, for example, a spinning solution in which a copolymer of acrylic series containing 30 to 70% by weight of acrylonitrile and 70 to 30% by weight of at least one other vinyl monomer copolymerizable with acrylonitrile is dissolved in an organic solvent, is added with various kinds of additives corresponding to desired whiteness, gloss, shade and the like, and then spun. At this time, the spinning method, the kinds of additives and the amount of additives to be added are adjusted so that the degree of surface unevenness of the fiber may be within the range as mentioned above. In general, when the amount of additives to be added is increased, the degree of surface unevenness of the fiber becomes larger but inorganic particles having a smaller diameter have a relatively few influence on the surface of the fiber to be produced. As a result, the control of the degree of the surface unevenness within the range as mentioned above is facilitated. That is, even when the amount of inorganic additive having a small particle size to be added is increased to improve the whiteness, the degree of surface unevenness may be kept in a relatively small degree, and therefore it is possible to set the center-line mean roughness to 0.13 .mu.m or less. For example, TiO.sub.2 as a preferred additive to improve the whiteness has a relatively small particle size and a relatively little influence on the surface of the fiber. Accordingly, when the amount of addition is changed in accordance with the whiteness to be desired, it is easy to keep the degree of the surface unevenness within the range as mentioned above. Vinyl monomers copolymerizable with acrylonitrile include vinyl chloride, vinylidene chloride, vinyl bromide, vinylidene bromide; acrylic acid ester, methacrylic acid ester; acrylamide, methacrylamide or mono- or dialkyl substituted compounds thereof; styrene or .alpha., .beta.-substituted styrene; vinyl acetate; vinyl pyrrolidone, vinyl pyridine or alkyl substituted compounds thereof; acrylic acid, methacrylic acid, itaconic acid, parastyrene sulfonic acid, 2,acrylamido-2-methyl propyl sulfonic acid, paramethacryloyloxybenzene sulfonic acid, methacryloyloxy-propyl sulfonic acid or their metal or amine salts. The copolymers of acrylic series may be obtained in a common vinyl polymerization process by using as an initiator a known compound such as, for example, peroxide compounds, azo compounds or various kinds of redox compounds. The copolymer of acrylic series is dissolved in an organic solvent such as, for example, acetone, acetonitrile, dimethyl formamide, dimethyl acetamide, and dimethyl sulfoxide to form a spinning solution. Incidentally, if necessary, a stabilizer being effective for the rust prevention, coloring prevention, weather resistance and the like, may be added. An additive such as TiO.sub.2 may be added to adjust the whiteness and gloss, however, it is necessary to adjust the amount to be added so that the degree of the surface unevenness of the fiber may be within the range as mentioned above. The fineness of synthetic fiber of acrylic series is 1 to 30 denier, preferably 3 to 20 denier. The fineness of less than 1 denier provides a toughless feeling, and if the fineness exceeds 30 denier, a rough feeling may be provided due to too much toughness, adversely. An organopolysiloxane is then adhered onto the surface of the synthetic fiber of acrylic series with the degree of the surface unevenness as mentioned above, to thereby yield the synthetic fiber of acrylic series with a given animal-hair feeling. It is preferable to use as the organopolysiloxane at least one selected from dimethylpolysiloxane, amino-modified silicone, epoxy-modified silicone and carboxy-modified silicone. The organopolysiloxane as mentioned above in the form of treatment solution is then adhered onto the surface of the fiber, which is then preferably subjected to a heat treatment at a temperature of 80.degree. C. or higher to enhance the softening effect. The temperature of heat treatment is preferably 90.degree. C. or higher, and more preferably 100.degree. C. or higher. The treatment solution containing mainly organopolysiloxane is preferably one in which the organopolysiloxane is emulsified with a surface active agent in water to adjust the viscosity and to obtain the stability upon the elapse of time. Since the treatment solution is loaded with a thermal and mechanical shear in the course of fiber production, the emulsion of organopolysiloxane should be so stable that it may not be destroyed by these shears. Further, to enhance the affinity for fibers, the emulsified treatment solution preferably may have a viscosity of 500 cp or less (at 25.degree. C.). The amount of organopolysiloxane adhered onto the surface of synthetic fiber of acrylic series is 0.01 to 0.7% by weight referred to the weight of fiber, preferably 0.03 to 0.5% by weight. The amount of less than 0.01% by weight provides a feeling of less sliminess, which does not give a good animal-hair feeling. If the amount thereof exceeds 0.7% by weight, it causes sticky feeling, which does not give an excellent feeling. The adhesion of organopolysiloxane may reduce the center-line mean roughness approximately by about 0.05 .mu.m or less. |
| PATENT EXAMPLES | available on request |
| PATENT PHOTOCOPY | available on request |
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