Abstract: There is disclosed an acrylic fiber (a) consisting of an acrylonitrile polymer comprising an acrylonitrile unit in at least 80 wt % and less than 95 wt %, (b) having a monofilament dry strength of 2.5 to 4.0 cN/dtex, (c) having a monofilament dry elongation of 35 to 50 %, and (d) forming a crack with a length of 20 &mgr;m or more in its tension rupture lateral surface along the filament axis direction when rupturing the monofilament in a tension test. The fiber has even orientation in its surface and inside; is significantly improved in dry strength, dry elongation and dyeability; and exhibits wool-like hand feeling. It is, therefore, quite suitable as a synthetic fiber for various applications such as a garment material, e.g., a sweater and a home furnishing material such as a pile.

Abstract: There is disclosed an acrylic fiber (a) consisting of an acrylonitrile polymer comprising an acrylonitrile unit in at least 80 wt % and less than 95 wt %, (b) having a monofilament dry strength of 2.5 to 4.0 cN/dtex, (c) having a monofilament dry elongation of 35 to 50%, and (d) forming a crack with a length of 20 &mgr;m or more in its tension rupture lateral surface along the filament axis direction when rupturing the monofilament in a tension test. The fiber has even orientation in its surface and inside; is significantly improved in dry strength, dry elongation and dyeability; and exhibits wool-like hand feeling. It is, therefore, quite suitable as a synthetic fiber for various applications such as a garment material, e.g., a sweater and a home furnishing material such as a pile.

Abstract: There is disclosed an acrylic fiber (a) consisting of an acrylonitrile polymer comprising an acrylonitrile unit in at least 80 wt % and less than 95 wt %, (b) having a monofilament dry strength of 2.5 to 4.0 cN/dtex, (c) having a monofilament dry elongation of 35 to 50%, and (d) forming a crack with a length of 20 &mgr;m or more in its tension rupture lateral surface along the filament axis direction when rupturing the monofilament in a tension test. The fiber has even orientation in its surface and inside; is significantly improved in dry strength, dry elongation and dyeability; and exhibits wool-like hand feeling. It is, therefore, quite suitable as a synthetic fiber for various applications such as a garment material, e.g., a sweater and a home furnishing material such as a pile.

Abstract: There is disclosed an acrylic fiber (a) consisting of an acrylonitrile polymer comprising an acrylonitrile unit in at least 80 wt % and less than 95 wt %, (b) having a monofilament dry strength of 2.5 to 4.0 cN/dtex, (c) having a monofilament dry elongation of 35 to 50%, and (d) forming a crack with a length of 20 &mgr;m or more in its tension rupture lateral surface along the filament axis direction when rupturing the monofilament in a tension test. The fiber has even orientation in its surface and inside; is significantly improved in dry strength, dry elongation and dyeability; and exhibits wool-like hand feeling. It is, therefore, quite suitable as a synthetic fiber for various applications such as a garment material, e.g., a sweater and a home furnishing material such as a pile.

Abstract: There is disclosed an acrylic fiber (a) consisting of an acrylonitrile polymer comprising an acrylonitrile unit in at least 80 wt % and less than 95 wt %, (b) having a monofilament dry strength of 2.5 to 4.0 cN/dtex, (c) having a monofilament dry elongation of 35 to 50%, and (d) forming a crack with a length of 20 &mgr;m or more in its tension rupture lateral surface along the filament axis direction when rupturing the monofilament in a tension test. The fiber has even orientation in its surface and inside; is significantly improved in dry strength, dry elongation and dyeability; and exhibits wool-like hand feeling. It is, therefore, quite suitable as a synthetic fiber for various applications such as a garment material, e.g., a sweater and a home furnishing material such as a pile.

Abstract: There is disclosed an acrylic fiber (a) consisting of an acrylonitrile polymer comprising an acrylonitrile unit in at least 80 wt % and less than 95 wt %, (b) having a monofilament dry strength of 2.5 to 4.0 cN/dtex, (c) having a monofilament dry elongation of 35 to 50%, and (d) forming a crack with a length of 20 &mgr;m or more in its tension rupture lateral surface along the filament axis direction when rupturing the monofilament in a tension test. The fiber has even orientation in its surface and inside; is significantly improved in dry strength, dry elongation and dyeability; and exhibits wool-like hand feeling. It is, therefore, quite suitable as a synthetic fiber for various applications such as a garment material, e.g., a sweater and a home furnishing material such as a pile.

Abstract: A distributed refractive index type optical transmission plastic article has a circular cross section of a radius r.sub.0 which is in a range of 0.4 to 0.6 mm. A refractive index distribution of the optical transmission article substantially approximates a predetermined ideal refractive index distribution curve at least in a range of 0.25r.sub.0 to 0.70r.sub.0 extending from a center axis toward a peripheral surface of the article. A refractive index n.sub.0 at a central part of the article is in a range of 1.4 to 1.6. The article has a refractive index distribution constant of larger than 0.15 mm.sup.-1 and smaller than 0.3 mm.sup.-1, and a modulation transfer function of at least 55%. This optical transmission article is made from uncured liquid substances each having a viscosity of between 10.sup.3 and 10.sup.8 poises. N (N.gtoreq.2) uncured liquid substances having refractive indexes n of n.sub.1 >n.sub.2 >n.sub.3 . . . n.sub.

Abstract: An image-reading device comprises a lens unit array comprising an array of distributed refractive index plastic cylindrical lens elements and plastic plates, adhering the distributed refractive index plastic cylindrical lens elements therebetween, and a plastic case containing and holding the lens unit array. The difference in the thermal expansion coefficients of the plates of the lens unit array and the plastic case is 5.0.times.10.sup.-5 cm/cm/.degree. C. or below, or more preferably, 3.0.times.10.sup.-5 cm/cm/.degree. C. or below. The plastic case is formed by connecting, in a longitudinal arrangement, a plurality of case segments formed by an injection molding.

Abstract: A distributed refractive index type optical transmission plastic article has a circular cross section of a radius r.sub.0 between 0.4 and 0.6 mm. A refractive index distribution of the optical transmission article substantially approximates predetermined ideal refractive index distribution curve at least in a range of 0.25r.sub.0 to 0.70r.sub.0 extending from a center axis toward a peripheral face of the article. The article has a refractive index n.sub.0 between 1.4 and 1.6 for its central part, a refractive index distribution constant between 0.3 and 0.7 mm.sup.-1, and a modulation transfer function (MTF) of at least 55%. This optical transmission article is made from uncured liquid substances each having a viscosity between 10.sup.3 and 10.sup.8 poises and refractive indexes n of n.sub.1 >n.sub.2 >n.sub.3 . . . n.sub.N when cured. N (N.gtoreq.

Abstract: Disclosed is a graded index lens array which gives good resolution even if its end surfaces are not fully polished during its manufacture and which is less likely to suffer loss in resolution due to damage to its surfaces comprising a plurality of graded index lenses made of a synthetic resin and arranged in parallel, characterized in that at least one end surface of the lens array is coated with a cured film formed from a cross-linkable resin consisting essentially of a multifunctional compound having at least two (meth)acryloyloxy groups per molecule, and a fluorinated alkyl (meth)acrylate.

Abstract: The graded-index optical transmission medium with a low transmission loss, a favorable index distribution and superior in softness etc. can be constituted by a mixture of polymers Pn having different refractive indices and by restricting the attenuation L.sub.F of the medium in accordance with the below inequality (I).The medium may advantageously be produced by way of admixing a thermoplastic polymer (A) and a monomer (B) able to form a polymer mutually soluble with the polymer (A), molding the mixture and volatilizing the monomer (B) from the surface of thus shaped substance. ##EQU1## wherein Wn are the respective proportions by weight of mixing of the polymers Pn to the whole of the mixture of the polymers Pn, and ##EQU2## Wn is equal to one.

Abstract: A plastic optical transmission element having a body in which the refractive index varies continuously in a radial direction from the interior toward the surface of the body, may be free from the troubles derived from irregularity of the index distribution and flare by having a layer containing a light-absorbing substance under the surface thereof. Such a layer may be formed by contacting an untreated element with a solvent containing the light absorbing substance, when the solvent is selected so as to be capable of at least partially dissolving the plastic of the element.