JP2600209B2 - Composite fiber yarn for molding and composite fiber fabric for molding - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention is a composite material excellent in strength, elastic modulus and workability, and is used for automobile parts such as radial tires, various mechanical structural parts, pressure vessels and pipes. It can be used as a reinforcing fiber in a wide range of fields, such as a reinforcing fiber for forming, and a forming composite fiber yarn used for producing the same, or itself as a reinforcing fiber in FRP and the like. It is about a possible thread.

[Related Art] As a composite reinforcing material using a thermoplastic resin as a matrix and reinforcing fibers as a dispersing material, for example, a glass fiber strand is opened by using static electricity, and a thermoplastic resin powder is attached and then heated and melted. To form a tape-like strand (Japanese Patent Publication No. 47-36467), or a flexible strand is obtained by coating a flexible thermoplastic resin on a strand of a reinforcing fiber to which a thermoplastic resin powder is adhered. And the like (Japanese Patent Laid-Open No. 60-36156).

[Problems to be Solved by the Invention] In such a composite material, what kind of reinforcing fiber is selected, and what kind of means are used to select a high melt viscosity thermoplastic resin (hereinafter sometimes referred to as a matrix) ) Is uniformly impregnated into the reinforcing fibers so as to reduce voids, or by what method the matrix and the reinforcing fibers are melt-molded without deteriorating the properties such as the strength and elastic modulus of the reinforcing fibers. Is the point.

In order to obtain a molding material with good impregnating properties using the conventional techniques as described above, it is necessary to use a powder of a micron unit as a matrix, and it is necessary to open reinforcing fibers, attach and melt the matrix, and in some cases, Complicated processes such as coating are required, and not only workability is not good, but also depending on the type of reinforcing fiber, the properties of the reinforcing fiber may be deteriorated due to the heat effect at the time of melt molding, and the performance of the molding composite material may be reduced. there were.

The present invention has been made in view of such a situation, and a composite fiber fabric for molding excellent in strength, modulus of elasticity and workability with extremely good impregnation of a matrix, and a fabric structure for producing the same. An object of the present invention is to provide a composite fiber yarn for molding which is a material or a yarn which can be used as a reinforcing fiber of FRP.

[Means for Solving the Problems] The yarn of the present invention is a composite fiber yarn for molding used as a material of a composite molded body composed of a matrix resin and a reinforcing fiber, and has excellent strength and elastic modulus. The gist is that ultra-high-strength polyethylene fibers are used as reinforcing fibers, and that the thermoplastic fibers having a melting point lower than that of the ultra-high-strength polyethylene fibers by 10 ° C. or more are used as matrix resin fibers, and that both are compositely mixed. I do. Further, the composite fiber fabric for molding of the present invention has a gist in an aspect consisting only of the composite fiber thread for molding and an aspect consisting of the composite fiber thread for molding and the fiber for matrix resin.

[Action] The present invention uses an ultra-high-strength polyethylene fiber (hereinafter sometimes referred to as a reinforcing fiber) having a high strength and a high modulus of elasticity. Considering the strength required for products such as automobile parts and mechanical structural parts manufactured at least, the tensile strength should be at least 20 g / denier or more, preferably 30 g / denier or more, more preferably 45 g / denier or more is required. Even when the yarn is used as a reinforcing material as it is, the above strength promises excellent results.

Regarding the denier number, if the fiber having a total denier of 100 to 1000 denier (10 to 100 filaments) is used for both the reinforcing fiber and the thermoplastic fiber for the matrix (hereinafter sometimes referred to as matrix fiber), for example, the electrospreading method can be used. Although the spread state is obtained, the mixed state of the matrix and the reinforcing fibers in the final composite molded article becomes more uniform, and an excellent composite effect is obtained, but is not limited to this range.

An example of a method for producing such a reinforcing fiber will be described below.

Solution spinning is performed using ultra high molecular weight polyethylene (for example, ultra high molecular weight polyethylene having a weight average molecular weight of 1 × 10 ⁵ or more, preferably 1 × 10 ⁶ or more), and the obtained gel fiber is drawn into a drawing zone (at an inlet temperature of (The drawing temperature is higher than the melting point of the supply fiber in the solvent used and lower than its melting point, while the outlet temperature is higher than the melting point of the supply fiber and lower than the melting point of the drawn fiber). It can be obtained by a novel high-magnification stretching method such as multi-stage stretching.

The reinforcing fiber thus obtained and the matrix fiber are combined to form a composite fiber yarn, and further to a composite fiber cloth, wherein the melting point of the matrix fiber is higher than the melting point of the reinforcing fiber.
It must be lower than 10 ° C. That is, when the fabric is melt-molded, the treatment is performed at a temperature close to the melting point of the reinforcing fiber, but the difference in melting point between the reinforcing fiber and the matrix fiber is 10%.
If the temperature is lower than ℃, it is not easy to control the temperature in the melt molding process of the fabric, and the physical properties of the reinforcing fibers are changed due to the thermal influence, and the performance such as the strength of the final composite molded product may be deteriorated. .

When the melting point of the matrix fiber is lower than the melting point of the reinforcing fiber by 10 ° C. or more, the temperature is higher than the softening point of the matrix fiber (preferably, a temperature higher than the temperature sufficient to melt the matrix fiber), and the melting point of the reinforcing fiber It is relatively easy to melt mold in the lower temperature range.
Therefore, the matrix is sufficiently impregnated into the reinforcing fibers so that the voids are reduced uniformly, and furthermore, the final composite molding does not cause deterioration in performance and the like due to the influence of the melting molding temperature on the physical properties of the reinforcing fibers. You can get things.

The matrix fiber is not particularly limited as long as it is made of a fiber-forming thermoplastic polymer that satisfies the above temperature conditions, and examples thereof include a polyethylene fiber and a polybutene-1 fiber. Is used, polyethylene fibers (melting point: 110 to 137 ° C.) and polybutene-1 fibers (melting point: 120 to 130 ° C.) are particularly preferable as matrix fibers because the melting point is 147 ° C.

In the present invention, a method of compounding the reinforcing fibers and the matrix fibers in a mixed fiber state is employed. The mixed fiber state refers to a state in which the reinforcing fibers 1 and the matrix fibers 2 are almost completely mixed with each other as shown in FIG. 1 (cross-sectional view). In the composite in the mixed state, the matrix is uniformly dispersed between the reinforcing fibers, the number of voids is reduced, and the strength of the final composite molded product can be improved.

Since the present invention uses fibers instead of powder as a matrix as described above, complicated operations are not required in any of the compounding process and the melt molding process, and the workability of the manufacturing process is improved. It will be extremely excellent.

The method of combining the matrix fibers and the reinforcing fibers in a mixed fiber state is not limited, and examples thereof include a Taslan method, an electric fiber opening method, and an interlace method.

 Hereinafter, these methods will be described.

(1) Taslan method This method is a turbulent disturbance method in which a plurality of filaments are supplied in a relaxed state to a fluid turbulent flow region by an air jet, and loops and entanglements are formed to form a bulky yarn. By this method, single filaments are separated from each other and disturbed in the turbulent flow area.By taking out from the turbulent flow disturbance area continuously without applying tension, the bulky yarn in which loops and entanglements etc. Can be obtained.

By applying this technology to a composite of a reinforcing fiber and a matrix fiber, both fibers can be composited with extremely high production efficiency. The characteristic of the composite yarn produced by the turbulent disturbance method is that a large number of loops and entanglements are formed as described above, and a unique composite yarn is produced by utilizing the characteristics of the reinforcing fiber and the matrix fiber. It is also very easy to melt-mold a fabric using the strip. That is, for a matrix fiber such as polyethylene or polybutene-1, the supply rate of the reinforcing fiber is reduced and the tension is increased, so that a loop or entanglement of the matrix fiber is formed for the reinforcing fiber in the turbulent flow region. . In particular, since the reinforcing fibers have a high modulus, it is possible to reduce the swirling in the turbulent flow region only by slightly increasing the tension. An important point is the feed speed ratio, which is determined by the mixing ratio of the two fibers, and the reinforcing fiber is desirably at a speed of 0.05 to 0.5 times, preferably 0.1 to 0.3 times the matrix fiber. If it is 0.05 times or less, the reinforcing efficiency of the final composite molded article is poor, while if it is 0.5 or more, the void ratio of the final composite molded article becomes high, and the formation of loops and entanglements of the reinforcing fibers in the turbulent flow area is not preferable. . According to the turbulent disturbance method, the total denier and the number of filaments of the two fibers are determined by mechanical conditions such as the feed rate ratio and the nozzle shape, fluid pressure, etc. Preferably, it is used.

(2) Electric Spreading Method As a method of producing a composite yarn by mixing a filament and a staple, the filament is spread using an electric spreader, and the staples are superimposed and twisted immediately before a front roller, There is a method in which both fibers are mixed and arranged without bias by winding. According to this method, a yarn in which filaments and staples of different fibers are continuously and uniformly mixed can be obtained.

By applying this method to the present invention, a very uniform composite yarn can be produced. In this case, the reinforcing fibers
It is preferable because a good spread state can be obtained by applying a voltage.

The denier and the number of filaments when using this method are also 100 to 1000 denier, and 10 to 100 filaments are suitable.By twisting after opening and mixing, the operability in the fabric production process can be improved, and further the fiber The patching between them becomes dense, which can also contribute to the reduction of voids in melt molding.

(3) Interlacing method The interlacing method creates two or more turbulent turbulent flow zones almost in parallel with the yarn axis, guides the filaments in this zone, applies tension to the extent that loops and crimps do not occur, and produces a non-bulky material. This is a technique for producing tight strands. The principle of the method is to impinge the fluid on the filament such that the fluid is perpendicular to the filament axis, while at the same time producing a turbulent vortex parallel to the filament, which turbulence is generated by the tension of the yarn and the velocity or velocity of the fluid. At the same time, the filament bundle is split to an extent corresponding to the pressure and, at the same time, the individual filaments are falsely twisted and convoluted and interlaced.

The degree of interlacing obtained is affected by tension, fluid pressure, overfeed rate, filament denier, filament count, yarn modulus, and the like. The effects of using the interlace method include high productivity, uniform mixing between fibers, easy production of a composite yarn fabric, and extremely low voids during melt molding. Is raised. Particularly important points in this method are the overfeed rate, tension, liquid pressure and denier, and the number of filaments.
Since the reinforcing fiber generally has a higher modulus than the matrix fiber, it is necessary to slightly increase the overfeed rate, and it is important to set the overfeed rate to preferably 105 to 110% by weight. The matrix fibers may be set based on the overfeed rate of the reinforcing fibers according to the content. Similarly, with respect to the tension and the fluid pressure, it is important to process the reinforcing fibers on the basis of a slightly higher condition than the conventional manufacturing conditions of the clothing yarn. In order to achieve particularly uniform mixing, the fluid pressure should be between 10 and 50 psig, preferably 30
~ 50 psig. Is preferred. In addition to the above-mentioned conditions, the denier and the number of filaments of both fibers to be composited are important for uniform fiber mixing. Since the linear density is closely related to the mixing in the turbulent vortex region, it is preferable that the linear density is the same in order to perform uniform mixing. In the present invention, 10
It is preferable that the fibers of 0 to 1000 denier and 10 to 100 filaments are interlaced yarns, and the denier of a single fiber is 1 to 10 denier, preferably 1 to 3 denier, which shows good processability and productivity. Thus, an excellent composite molded article having sufficient workability obtained in the weaving and knitting steps and the melt molding step.

The composite fiber fabric for molding of the present invention can be formed into a fabric using only the composite fiber yarn for molding (hereinafter, sometimes simply referred to as a yarn) obtained in this manner, and used for melt molding. Alternatively, a fabric can be formed and melt-molded by partially using the yarn and using the matrix fiber in the remainder.

In any of the above methods, when the mixing ratio of the reinforcing fiber and the matrix fiber in the obtained fabric is less than 5% (meaning by weight, hereinafter the same), the final composite molded product If the reinforcing efficiency is poor, and if it exceeds 80%, the matrix content is low, the impregnation degree is poor, and the void ratio of the final composite molded product is undesirably large. Therefore, the content of the reinforcing fibers in the fabric is 5 to 80%, preferably 10 to 70%, and more preferably 20 to 60%.

In the fabric of the present invention, comparing the composite fiber fabric of the present invention with only the composite fiber yarn and the composite fiber fabric of the composite fiber yarn and the matrix fiber, the mixing of the reinforcing fiber and the matrix fiber For the uniformity, the former method is better and more preferable. That is, in the former case, the uniformity can be obtained at the level of the single fiber constituting the yarn, whereas in the latter case, the uniformity is maintained between the yarn and the matrix fiber composited therewith. Therefore, the impregnating property of the matrix fiber with respect to the reinforcing fiber and the strength characteristics of the final composite molded article are also excellent in the former case.

Incidentally, the form of the composite fabric for molding according to the present invention includes, of course, a woven fabric, a knitted fabric or a nonwoven fabric, but it goes without saying that the woven structure or the knitted structure is not limited. The forming composite fiber fabric produced by the knitting structure or the like from the yarn according to the present invention is cut into a predetermined size to be used in the secondary processing process, and a number of sheets equal to the weight of the composite molded product are stacked. Use as a sample. The sample, which has been preheated to a temperature above the softening point of the matrix fibers (preferably sufficient to melt the matrix fibers), is then placed in a mold.
Finally, the mold is pressed to form a desired shape.
The pressing pressure generally needs to be 50 to 150 kg / mm ² with respect to the projected area, and the higher the pressing speed, the better, and preferably 1 to 2 seconds. The temperature of the mold is preferably equal to or lower than the melting point of the matrix fiber, and the cooling time is determined by the thickness of the thickest part of the molded article. In addition, the composite fiber fabric for molding may be used as a blank in which matrix fibers are previously melt-impregnated with a hot press roll or the like, and the preheating temperature is set to be equal to or lower than the melting point of the matrix fibers, and subjected to solid-state stamping by plastic deformation.

Hereinafter, embodiments will be described. However, the present invention is not limited to the following embodiments, and appropriate design changes in the spirit of the above and below are included in the technical scope of the present invention.

[Examples] In the following examples, the measurement of the strength and elongation characteristics of the fibers was performed by the following method.

Using Tensilon manufactured by Toyo Baldwin Co., the SS curve of a single fiber was measured under the conditions of a sample length (gauge length) of 30 mm and an elongation rate of 100% / min. Tensile strength (g / d), initial elastic modulus (g)
/ d). The initial elastic modulus was calculated from the maximum gradient near the origin of the SS curve. Each characteristic value was an average value measured for 20 single fibers.

Example 1 Ultra-high strength polyethylene fiber having a tensile strength of 32 g / denier, 400 denier and 200 filaments (molecular weight: 20
An interlacing machine with two pairs of opposed fluid conduits is opened using polyethylene fiber (melting point: 120 ° C) of 400 denier and 150 filaments as the matrix fiber as a reinforcing fiber of 100,000, melting point: 147 ° C. The composite yarn was used.

By making the fluid pressure 50 psig. And compounding in a turbulent vortex area at a speed of about 500 m / min, both fibers were uniformly mixed.
A composite yarn of 0 denier was obtained. Next, a plain woven fabric having a warp density of 50 yarns / inch and a weft yarn density of 50 yarns / inch was woven using the composite yarn as a warp and the same polyethylene fibers as those used for the composite yarn as a weft. A sheet cut out from the plain woven fabric in a size of 20 cm × 20 cm was used as a sample, and the temperature was set at 80 ° C. for 16 hours.
Vacuum drying was performed under a condition of 1 mmHg or less, and three sheets were stacked so that the composite yarns of each layer were in the same direction. The laminated sheet was filled in a mold previously heated to 120 ° C., preheated and melted under a light load for 3 to 5 minutes, and then subjected to heat compression molding at a pressure of 50 to 70 kgf / cm ² . It was quenched under pressure to 60 ° C before being removed from the mold.

The polyethylene fiber used for the composite yarn and the weft by melt molding in the above procedure is melt-impregnated just before the ultra-high-strength polyethylene fiber remaining as a reinforcing material, and unidirectional with the ultra-high-strength polyethylene fiber as the reinforcing material A reinforced laminate was obtained. The tensile test was performed in accordance with JIS K7054 with the axial direction of the ultra high strength polyethylene fiber as the longitudinal direction of the test piece. As a result, the volume content of the ultra high strength polyethylene fiber was about 35%. Yes, a tensile strength of 1220 to 1320 MPa was obtained. The compressive strength was 35 MPa. The void ratio of this laminate was 2% or less, and had an extremely excellent appearance. A reinforced laminated board for comparison was obtained in the same manner as in Example 1 except that the same material as in Example 1 was used to prepare a composite yarn. The volume content of the ultrahigh-strength polyethylene fiber was 35%. , Void ratio is less than 2%, tensile strength is 1050
121230 MPa, and compressive strength was 18 MPa.

[Effect of the Invention] Since the present invention is configured as described above, by using a yarn in which the ultra-high-strength polyethylene fiber and the thermoplastic matrix fiber according to the present invention are combined in a mixed state,
It has become possible to provide a composite fiber fabric for molding having extremely good impregnation properties, few voids, and extremely excellent strength, elasticity and workability with good workability. Further, the composite fiber yarn of the present invention can be used as a reinforcing material for composite in the yarn form.

[Brief description of the drawings]

 FIG. 1 is a cross-sectional view illustrating an example of a mixed state. 1. Ultra high strength polyethylene fiber 2. Thermoplastic organic fiber

Claims (3)

(57) [Claims] 1. A composite fiber yarn for molding used as a material for a composite molded article comprising a matrix resin and a reinforcing fiber, wherein an ultra-high-strength polyethylene resin having excellent strength and elastic modulus is used as the reinforcing fiber. A composite fiber yarn for molding, wherein a thermoplastic fiber having a melting point lower than that of ultra-high-strength polyethylene fiber by 10 ° C. or more is used as a fiber for a matrix resin, and both are mixed in a mixed fiber state. 2. A composite fiber fabric for molding used as a material of a composite molded article comprising a matrix resin and a reinforcing fiber, wherein an ultra-high-strength polyethylene fiber having excellent strength and elastic modulus is used as the reinforcing fiber. What is claimed is: 1. A fiber fabric for molding, comprising a thermoplastic fiber having a melting point lower than that of a high-strength polyethylene fiber by 10 ° C. or more as a matrix resin fiber, and comprising only a composite fiber yarn in which both fibers are mixed in a mixed fiber state. 3. A composite fiber fabric for molding used as a material of a composite molded article comprising a matrix resin and a reinforcing fiber, wherein an ultra-high-strength polyethylene fiber having excellent strength and elastic modulus is used as the reinforcing fiber. A thermoplastic fiber having a melting point lower than that of high-strength polyethylene fiber by 10 ° C. or more is used as a matrix resin fiber, and a composite fiber yarn in which both are combined in a mixed fiber state and the matrix resin fiber are characterized by comprising Molding composite fiber cloth.