JP3927795B2 - Carbon fiber bundle and its textile fabric - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a carbon fiber bundle excellent in handleability while maintaining a form, and a woven fabric comprising the carbon fiber bundle.
[0002]
[Prior art]
Most fabrics formed using reinforcing fibers such as glass fibers, carbon fibers, and aramid fibers are used as fiber-reinforced plastics impregnated and cured with a resin. In order to maximize the mechanical properties of these woven fiber reinforced plastics, it is required that the yarn constituting the woven fabric has less disturbance such as meandering and misalignment, and that the woven form is stable. In many cases, woven fiber reinforced plastics are required to have a beautiful appearance in combination with mechanical properties.
[0003]
Many studies have been made as a method for maintaining the woven form of the reinforcing fiber woven fabric. Usually, a woven fabric is formed by covering a reinforcing fiber with a low-melting-point heat-fusible resin, and then heating the woven fabric. There is a method of fusing resin.
[0004]
Further, for example, in Japanese Patent Application Laid-Open No. 64-40632, the reinforcing fiber bundles are aligned in one direction or in the crossing direction, and the woven structure is formed by the first and second auxiliary yarns arranged in a crossing manner between the adjacent reinforcing fiber bundles. And the thermoplastic fiber bundle is continuously or discontinuously attached to the filament along the first auxiliary yarn or the second auxiliary yarn, and the reinforcing fiber bundle is integrally held by the thermoplastic polymer. Auxiliary yarns that cross each other are joined.
[0005]
Further, for example, according to Japanese Patent Application Laid-Open No. 7-314443, a shape stabilizer composed of a thermosetting resin or a thermoplastic resin having a glass transition temperature of 70 ° C. or higher is set to 0 with respect to the fiber material weight of the carbon fiber fabric. By adhering in the range of 5 to 10% by weight, settling of the matrix resin of the surface layer portion in the prepreg into the carbon fiber fabric is prevented, so that the tackiness as the prepreg is maintained for a long time, and the prepreg Is a fiber-reinforced composite material having excellent surface smoothness with no resin defects on the surface of the molded article.
[0006]
Further, for example, in Japanese Patent Application Laid-Open No. 8-158207, when weaving a woven fabric by setting warps and wefts made of high heat-resistant fibers on a loom, the weaving portion 1 and the winding portion 1 after the weaving. By applying a hot melt resin to the woven fabric, solidifying the resin, and binding the warp and the weft, the constituent fibers are coated with the resin, and the warp and the weft are firmly bound, and the loom It is said that it is possible to obtain a woven fabric that maintains a clean fabric immediately after weaving without disturbing the arrangement of warps and wefts, since the woven fabric can be spotted in the state of being set in the process.
[0007]
[Problems to be solved by the invention]
However, in the method of forming a woven fabric by previously covering the reinforcing fiber with a low-melting-point heat-fusible resin, the reinforcing fiber bundle is covered with the heat-fusible resin, and the matrix resin extends to the inside of the reinforcing fiber bundle. Is hard to penetrate. Further, in the method disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 7-314443, it is merely a point adhesion between the first and second auxiliary yarns that become warp yarns and weft yarns arranged in an intersecting manner between adjacent reinforcing fiber bundles. For this reason, the cross-sectional shape of the reinforcing fiber bundle is deformed relatively easily, and in particular, in a woven fabric with a small number of driven-in, it is not possible to suppress opening and misalignment.
[0008]
On the other hand, in the methods disclosed in JP-A-7-314443 and JP-A-8-158207, the draping property of the fabric is remarkably lowered and the resin impregnation property is often lowered. Moreover, when it deform | transforms in order to give a shape to such a textile fabric, an adhesion point may peel.
[0009]
The present invention has been made to solve such a problem, and a specific object thereof is to improve the shape stability of the reinforcing fiber bundle and the reinforcing fiber bundle fabric at room temperature, making it easy to handle and high drapeability. An object of the present invention is to provide a woven fabric using a carbon fiber bundle and a reinforcing fiber bundle capable of maintaining the same.
[0010]
[Means for solving the problems and effects]
As a result of intensive studies to achieve the above object, the present inventors have reached the present invention.
That is, the present invention is a carbon fiber bundle provided with fine particles having an average particle diameter of 10 to 20000 nm, the fine particles having a surface layer and a core, and the surface layer is a monomer containing an acroyl group or a methacryloyl group. A carbon fiber formed of a non-crystalline thermoplastic resin having a glass transition temperature of −10 to + 20 ° C. and having a core mainly composed of a monomer containing an acryloyl group or a methacryloyl group. a textile using a flux and their carbon fiber bundle. Thereby, it becomes possible to improve the form stability of the carbon fiber bundle and the reinforcing fiber bundle fabric at room temperature to facilitate handling and maintain high drape. In particular, the effect is exhibited in the spread widened fiber bundle and its woven fabric.
[0011]
A carbon fiber bundle is used as the reinforcing fiber bundle used in the present invention . Although organic fiber bundles such as orientation fiber bundles such as glass fibers and alumina fibers and aramid fibers can also be mentioned, carbon fibers are particularly lightweight and excellent in specific strength and specific modulus, and also in heat resistance and chemical resistance. This is particularly preferable.
[0012]
The fine particles imparted to the carbon fiber bundle are the most important in the present invention.
It is essential that the fine particle is an amorphous thermoplastic resin having at least a surface layer having a glass transition temperature of −10 to + 20 ° C. When the melting point of the crystalline thermoplastic resin is lower than room temperature, it is difficult to obtain sufficient shape retention in the carbon fiber bundle and the woven fabric including the carbon fiber bundle due to high fluidity, and the melting point is higher than room temperature. The carbon fiber bundle and the draping property of the fabric composed of the carbon fiber bundle are deteriorated, and a large stress is applied to the bonded portion due to deformation of the carbon fiber bundle or the carbon fiber fabric such as unwinding or shape imparting. Depending on the case, the adhesion may be peeled off.
[0013]
Here, the fine particles need to be a core / shell type, and as a requirement of the present invention, the glass transition temperature of the shell serving as the surface layer is −10 to + 20 ° C. Thereby, it becomes possible to achieve both drape maintenance in improving the normal temperature of shape stability of the fabric comprising a carbon fiber bundle and carbon fiber bundle.
[0014]
When the glass transition temperature of the fine particle surface layer is lower than −10 ° C., the shape stability is lowered, and in some cases, the surface of the carbon fiber bundle or the carbon fiber fabric may be sticky, and the handleability may be lowered. When the glass transition temperature of the fine particle surface layer exceeds + 20 ° C., the resin of the fine particle surface layer becomes a glass state at room temperature, so that the drapeability of the carbon fiber bundle and the woven fabric composed of the carbon fiber bundle is reduced. Since a large stress is applied to the bonding portion due to the deformation of the carbon fiber fabric, the bonding may be peeled off in some cases.
[0015]
Here, the glass transition temperature can be usually measured by DSC or dynamic viscoelasticity measurement, but is not in the range for the core / shell type fine particles. Accordingly, these glass transition temperatures (Tg) are obtained by the following formula.
1 / (Tg + 273) = W1 / {100 × (Tg1 + 273)} + W2 / {100 × (Tg2 + 273)} +... + Wn / {100 × (Tgn + 273)}
Where Tg is the glass transition temperature (° C.) of the amorphous thermoplastic resin, and Tg1, Tg2,..., Tgn are the glass transition temperatures (° C.) of the homopolymers of the monomer units constituting the amorphous thermoplastic resin. , W1, W2,..., Wn are the weight fractions (%) of each monomer unit constituting the amorphous thermoplastic resin.
[0016]
The resin of the fine particle surface layer is not particularly limited as long as it is an amorphous thermoplastic resin having a glass transition temperature of −10 to + 20 ° C. Any resin can be used. From the viewpoint of wettability with a matrix resin when producing fiber reinforced plastics and adhesion to the matrix resin, an amorphous thermoplastic resin mainly composed of a monomer containing an acryloyl group and / or a methacryloyl group is used. Preferably used. Also, from the standpoint of mechanical properties when made into fiber reinforced plastic and the impregnation property of the matrix resin, a resin containing a glycidyl group as a reactive functional group, for example, a resin containing glycidyl acrylate, glycidyl methacrylate or the like as a monomer unit is preferably used. Can be used.
[0017]
When the fine particles have a multilayer structure, a polymer having a monomer containing an acryloyl group or a methacryloyl group as a main component can be used as the core, that is, the core. When performing melt bonding by heating, by suppressing the flow of the fine particles, it becomes easier to maintain a partially bonded state of the filament, and from the point of view of mechanical properties when it is made fiber reinforced plastic, An amorphous resin having a glass transition temperature of 30 ° C. or higher can be suitably used.
[0018]
The amorphous resin having a glass transition temperature of 30 ° C. or higher is not particularly limited as long as it has a glass transition temperature of 30 ° C. or higher, and a normal amorphous thermoplastic resin is used .
[0019]
The fine particle diameter is preferably 10 to 20000 nm in average particle diameter. If it is less than 10 nm, many upon imparted to the carbon fiber bundle is buried in the carbon fiber bundle, it must be applied a large amount of fine particles in order to ensure the adhesion between the carbon fiber bundle. If it exceeds 20000 nm, the particles are large, so that adhesion spots are likely to occur. Further, in some cases, there is a possibility that a feeling of unevenness appears finely on the surface of the carbon fiber bundle or the carbon fiber fabric. More preferably, the thickness is 30 to 10,000 nm.
[0020]
The amount of fine particles applied to the carbon fiber bundle is preferably 0.1 to 5% by weight of the reinforcing fiber bundle. If it is less than 0.1% by weight, the adhesion between the carbon fiber bundles is insufficient, and if it exceeds 5% by weight, the mechanical properties of the fiber-reinforced plastic may be affected. Further, the fine particles may be applied to the entire surface layer of the carbon fiber bundle, or a part thereof may be selected and applied. For example, in a flat carbon fiber bundle, it is possible to form the imparted portion and the non-applied portion with a constant or irregular pitch that imparts fine particles only to one surface thereof.
[0021]
Examples of the method for applying the fine particles include a method in which the fine particles are sprayed on the carbon fiber bundle, and a fine particle emulsion is applied to the carbon fiber bundle and dried, but is not particularly limited. In view of the low glass transition temperature (Tg) on the surface of the fine particles and the control of the amount of fine particles attached, a method of applying the fine particles to the carbon fiber bundle in an emulsion state is preferably used.
[0022]
This emulsion may be either emulsified during polymerization or emulsified after polymerization, but the fine particles obtained by emulsification during polymerization can be suitably used because the particle size can be easily controlled. Further, water is preferable as the solvent of the emulsion, but it is also possible to add a small amount of an organic solvent such as alcohols and ketones as long as the stability of the emulsion is not impaired. Examples of the method for imparting to the carbon fiber when the fine particles are made into an emulsion include immersion, touch roll, roll coat, spray, and passage in a spray atmosphere, but are not particularly limited.
[0023]
The carbon fiber bundle of the present invention is particularly preferably used for the fiber that has been spread and widened. This is because according to the present invention, not only the woven form of the carbon fiber fabric but also the form of the carbon fiber bundle can be favorably maintained. Examples of the spreading and widening method for carbon fiber bundles include fluid injection, peristaltic movement of guide means, abrasion, air suction, ultrasonic waves, and high linear pressure. However, there is no particular limitation. As the provision of fine particles to the carbon fiber bundle subjected to the spread widening treatment, fine particles may be imparted to the carbon fiber bundle before performing the widening spread treatment, and then the widening treatment may be performed, or after the widening treatment. Fine particles may be imparted to the carbon fiber bundle.
[0024]
In the spread and widening process such as jet fluid, air suction, and ultrasonic waves, it is possible to apply the spread process. For example, in the spread widening by the jet fluid, it is possible to spray the emulsion directly or to spray the air in which the emulsion is dispersed, and in the air suction opening, to spray the emulsion in the atmosphere around the suction, etc. Is possible.
[0025]
The carbon fiber bundle of the present invention may be formed as it is by a method such as filament winding or drawing, or may be formed into a woven fabric by weaving, or as a prepreg impregnated with a matrix resin in one or multiple directions. Also good. Of course, it is good also as a prepreg by making a textile fabric and impregnating with matrix resin. In particular, it can be suitably used as a reinforcing fiber fabric or a reinforcing fiber fabric prepreg. When a reinforced fiber fabric is used, a woven fabric having a more stable woven form and excellent drape can be obtained by heat-sealing after weaving.
[0026]
The matrix resin impregnated in the carbon fiber bundle and carbon fiber fabric of the present invention is a resin used as a matrix of fiber reinforced plastic such as epoxy resin, unsaturated polyester resin, vinyl ester resin, acrylic resin, BT resin, etc. There is no particular limitation. Among these, an epoxy resin is preferably used because of its adhesiveness to the reinforced fiber and the mechanical strength when it is made into a fiber reinforced plastic.
[0027]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be specifically described with reference to typical examples.
[0028]
(Comparative Example 1)
A carbon fiber bundle 12,000 filaments (Pyrofil TR50S manufactured by Mitsubishi Rayon Co., Ltd.) was spread by air suction to obtain a carbon fiber bundle A having a tow width of 20 mm. The widened state of the carbon fiber bundle A was unstable, and the tow width contracted only by lifting.
[0029]
Carbon fiber bundle A was used for both the warp and the weft, and both the warp and the weft were driven into a plain weave structure with a pitch of 20 mm to produce a carbon fiber fabric B. This carbon fiber woven fabric B had very low form stability, causing misalignment and shrinkage of the tow width just by touching, and the handleability was very poor.
[0030]
Example 1
Methyl methacrylate (MMA) / n-butyl acrylate (nBA) / ethylene glycol dimethacrylate (EDMA) is 41.4 / 55.2 / 3.4 by weight in the core, and MMA / n-BA / methyl acrylate is in the shell. An acrylic emulsion having a weight ratio of 40.6 / 56.4 / 3.0 and a core / shell ratio of 40/60 was prepared by emulsion polymerization. The Tg of the core was calculated to be 1.7 ° C., and the Tg of the shell was calculated to be 3.8 ° C. This emulsion had a resin content of about 38% by weight. Further, the resin particle diameter in the emulsion was measured by a laser diffraction / scattering particle size distribution analyzer HORIBA LA-910, and it was 93 nm on average.
[0031]
The emulsion was spray-coated on one surface of the carbon fiber bundle A and dried to obtain a carbon fiber bundle C provided with fine particles . The amount of particles attached to the carbon fiber bundle C was about 0.6% by weight. The carbon fiber bundle C was morphologically stable and retained the toe width even when lifted. The carbon fiber bundle C was richer in flexibility although it felt harder than the reinforcing fiber bundle A when no particles were applied.
[0032]
Warp, weft also used carbon fiber bundles C the particles have been applied to any, both come Arise, a plain weave of implantation pitch 20mm organized, heat sealed over the further 80 ° C., fusing pressed under the conditions of 40 sec, the carbon fibers Fabric D was made. This carbon fiber fabric D had high form stability and did not cause misalignment or shrinkage of the tow width even when lifted, and was easy to handle. Further, it was rich in drapability, and even when it was wound around a 3-inch paper tube, peeling or the like did not occur at the textured bonded portion.
[0033]
(Example 2)
A carbon fiber bundle E was obtained in the same manner as in Example 1 except that the particle adhesion amount was 1.5%. The carbon fiber bundle E was morphologically stable and retained the toe width even when lifted. Moreover, the carbon fiber bundle E felt richer and harder than the carbon fiber bundle A , but was rich in flexibility.
[0034]
Warp, weft using carbon fiber bundle E either to plain weave implantation pitch 20 mm, further 80 ° C., heat sealed over the fusing pressed under the conditions of 40 sec, to prepare a carbon fiber woven fabric F. This carbon fiber woven fabric E had high form stability, and even when it was lifted, the misalignment and shrinkage of the tow width did not occur, and the carbon fiber woven fabric E had good handleability. Further, it was rich in drapability, and even when wound on a 3-inch paper tube, no peeling of the texture adhesion occurred.
[0035]
(Comparative Example 2)
An acrylic emulsion 2 having a weight ratio of MMA / ethyl acrylate (EA) / n-octyl mercaptan (n-OM) of 80/20 / 0.03 was prepared by emulsion polymerization. The Tg of the resin component in the emulsion was calculated to be 71 ° C. The emulsion 2 had a resin content of about 38% by weight. Moreover, the resin particle diameter in the emulsion was 188 nm on average.
[0036]
The emulsion 2 was spray-coated on one surface of the reinforcing fiber bundle A and dried to obtain a carbon fiber bundle G. The particle adhesion amount of the carbon fiber bundle G was about 1.5% by weight fraction. The carbon fiber bundle G was morphologically stable and retained the tow width even when lifted, but it was much harder than the carbon fiber bundle A.
[0037]
Carbon fiber bundles G were used for both the warp and weft, and both the warp and weft were driven into a plain weave structure with a pitch of 20 mm, and further subjected to fusing press at 120 ° C. for 40 sec to produce a carbon fiber fabric H. This reinforcing fiber woven fabric H had high form stability and did not cause misalignment or shrinkage of the tow width even when lifted, and was easy to handle. However, the draping property is low, and when it is wound around a 3-inch paper tube, the texture adhesion peels off, and thereafter, the misalignment easily occurs.
[0038]
(Example 3)
Acrylic emulsion 3 with MMA / nBA of 74/26 by weight in the core, MMA / nBA / methyl acrylate (MAA) of 46/50/4 by weight, and core / shell ratio of 40/60 by emulsion is prepared by emulsion polymerization. did. The Tg of the core was calculated to be 40.9 ° C, and the Tg of the shell was calculated to be 3.8 ° C. The emulsion 3 had a resin content of about 38% by weight. Moreover, when the resin particle diameter in an emulsion was measured, it was 96 nm on average.
[0039]
Emulsion 3 was sprayed on one surface of carbon fiber bundle A and dried to obtain carbon fiber bundle I. The particle adhesion amount of the carbon fiber bundle I was about 1.5% by weight. The carbon fiber bundle I was morphologically stable and retained the toe width even when lifted. Moreover, the carbon fiber bundle I felt richer and harder than the carbon fiber bundle A , but was rich in flexibility.
[0040]
Reinforcing fiber fabric J was produced in the same manner as in Example 1 using carbon fiber bundle I for both warp and weft. This carbon fiber woven fabric J had high form stability, and even when lifted, the misalignment and shrinkage of the tow width did not occur, and the carbon fiber woven fabric J had good handleability. Further, it was rich in drapability, and even when wound on a 3-inch paper tube, no peeling of the texture adhesion occurred.
[0041]
Example 4
Acrylic emulsion 4 having a weight ratio of MMA / nBA / EDMA of 46/50/2 in the core and a weight ratio of MMA / nBA / glycidyl methacrylate (GMA) of 42/48/10 and a core / shell ratio of 40/60 in the shell. Prepared by emulsion polymerization. The Tg of the core was calculated to be 1.7 ° C., and the Tg of the shell was calculated to be 3.8 ° C. The emulsion 4 had a resin content of about 35% by weight. Moreover, when the resin particle diameter in an emulsion was measured, it was 119 nm on average.
[0042]
Emulsion 4 was spray-coated on one surface of carbon fiber bundle A and dried to obtain carbon fiber bundle K. The amount of particles attached to the carbon fiber bundle K was about 1.6% by weight. The carbon fiber bundle K was morphologically stable and retained the toe width even when lifted. Moreover, the carbon fiber bundle K felt richer and harder than the reinforcing fiber bundle A, but was rich in flexibility.
[0043]
A carbon fiber fabric L was produced in the same manner as in Example 1 using the reinforcing fiber bundle 6 for both the warp and the weft. This carbon fiber woven fabric L has high form stability, and even when lifted, the misalignment and shrinkage of the tow width do not occur, and the carbon fiber woven fabric L has good handleability. Further, it was rich in drapability, and even when wound on a 3-inch paper tube, no peeling of the texture adhesion occurred.
[0044]
(Example 5)
Acrylic emulsion 5 having a weight ratio of MMA / nBA of 74/26 in the core, a weight ratio of MMA / nBA / GMA of 42/48/10, and a core / shell ratio of 40/60 was prepared by emulsion polymerization. The Tg of the core was calculated to be 40.9 ° C, and the Tg of the shell was calculated to be 3.8 ° C. The emulsion 5 had a resin content of about 33% by weight. Moreover, when the resin particle diameter in an emulsion was measured, it was 92 nm on average.
[0045]
Emulsion 5 was spray-coated on one surface of carbon fiber bundle A and dried to obtain carbon fiber bundle M. The amount of particles attached to the carbon fiber bundle M was about 1.7% by weight. The carbon fiber bundle M was morphologically stable and retained the toe width even when lifted. The carbon fiber bundle M felt richer and harder than the carbon fiber bundle A, but was rich in flexibility.
[0046]
A carbon fiber woven fabric N was produced in the same manner as in Example 1 using the carbon fiber bundle M for both the warp and the weft. This carbon fiber woven fabric N had high form stability, and even when it was lifted, the misalignment and shrinkage of the tow width did not occur, and the carbon fiber woven fabric N had good handleability. Further, it was rich in drapability, and even when wound on a 3-inch paper tube, no peeling of the texture adhesion occurred.

Claims (8)

A carbon fiber bundle provided with fine particles having an average particle size of 10 to 20000 nm,
The fine particles have a surface layer and a core part,
The surface layer is formed of an amorphous thermoplastic resin having a glass transition temperature of −10 to + 20 ° C. based on a monomer containing an acryloyl group or a methacryloyl group,
The core is a carbon fiber bundle formed of a polymer whose main component is a monomer containing an acryloyl group or a methacryloyl group. The carbon fiber bundle of Claim 1 whose glass transition temperature of the polymer which comprises a core part is 30 degreeC or more . The carbon fiber bundle according to claim 1 or 2, wherein the fine particles contain a glycidyl group as a reactive group . The carbon fiber bundle according to any one of claims 1 to 3, wherein the fine particles are provided as an emulsion. The carbon fiber bundle according to any one of claims 1 to 4, wherein the adhesion amount of the fine particles is 0.1 to 5% by weight of the reinforcing fiber bundle. The carbon fiber bundle according to any one of claims 1 to 5, wherein the reinforcing fiber bundle before the fine particles are applied is subjected to a fiber spreading process. A woven fabric obtained by weaving the reinforcing fiber bundle according to any one of claims 1 to 6. A sealing fabric obtained by heating the fabric according to claim 7.