JPH01280017A - Multifilament yarn for formed product matrix resin - Google Patents

Abstract

PURPOSE:To obtain the title multifilament yarn with each specified primary yield stress and elongation at break, excellent in kandleability until a formed product is obtained therefrom, by melt spinning of a thermoplastic polymer followed by drawing and not imparting substances other than water during the above fiber-forming process. CONSTITUTION:The objective multifilament yarn >=0.8g/d in primary yield stress and 45-100% in elongation at break, suitable for obtaining formed products reinforced with reinforcing fiber, obtained by melt spinning of a thermoplastic polymer such as polyarylene ether ketone or polyetherimide followed by, if needed, drawing in a warm water both, and not imparting substances other than water during this fiber-forming process.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a matrix resin that is used together with reinforcing fibers to obtain a molded article in which the matrix resin embeds reinforcing fibers. Regarding multifilament yarn for material resin.

[Conventional technology]

Molded products in which the base material resin embeds reinforcing fibers are -
Generally speaking, it is made by melt extrusion molding of a so-called compound resin in which short reinforcing fibers such as glass fibers, graphite fibers, aramid fibers, etc. are dispersed in a thermoplastic polymer. In this molding method, the length of the reinforcing fibers must be short, and the direction of the reinforcing fibers is random, so there is a problem that the reinforcement of the base resin by the reinforcing fibers is insufficient.

Therefore, as a molding method to solve the above-mentioned problems, a method in which a fabric such as a reinforcing fiber fabric and a thermoplastic polymer film are layered, pressed and heated using a template, etc., and a reinforcing fiber fabric and a thermoplastic As described in Japanese Patent Application Laid-Open No. 59-47233, a prebrag such as PC-N manufactured by ICI Co., Ltd., which is obtained by impregnating a molten polymer on the alignment of reinforcing fibers, is used instead of overlapping with a film. 4,479,999 using a fabric made of reinforcing fibers and thermoplastic fibers, or using a thermoplastic fiber fabric instead of the thermoplastic film. method is known. Among these methods, the method using pre-brag has a problem in that the amount of deformation cannot be increased when making a molded product from the pre-brag because the pre-brag has high rigidity and poor drapability. Also,
Compared to methods using fiber fabrics such as thermoplastic film fabrics, the amount of deformation is limited, and compared to methods using prepreg or mixed fiber fabrics, there is a problem in that the base resin is less likely to penetrate between reinforcing fibers. Note that these methods are suitable for use in molded products with relatively thin walls or molded products with uniform wall thickness.

Furthermore, for molded products such as cone shapes, a filament winding method is also known in which a thermoplastic fiber yarn, a reinforcing fiber yarn, or a mixed fiber yarn of both fibers is wound around a mold and then pressurized and heated.

In the filament winding method, a mixed fiber tow in which reinforcing fibers and thermoplastic fibers are intimately mixed, which is suitably used as yarn or warp yarns of textiles made of reinforcing fibers and thermoplastic fibers, is used in JP-A-60. It is known from the publication No.-209034. Conventionally known mixed fiber technology is used to manufacture this tow. In other words, when insulating thermoplastic fibers are mixed with insulating reinforcing fibers such as aramid fibers and glass fibers, these fibers are generally treated with antistatic agents and oils during the spinning process such as melt spinning and drawing. If emulsification is required, an oil agent containing a similar lubricant or an emulsifier such as polyoxyethylene oleyl ether is added, and an antistatic agent in the oil agent.

Since the emulsifier has surface activity and absorbs water, giving conductivity to the fiber surface, each multifilament yarn is brought into contact with a high-voltage electrode and the filaments of each yarn are opened by repulsion due to Coulomb force. This is done by either stacking both yarns in a state that they are still in place and then combining them into a single yarn, or by passing the combined yarn through an entangling treatment nozzle such as a fluid (generally air) jetting nozzle to further promote the mixing. In addition, when mixing thermoplastic fibers with conductive reinforcing fibers such as carbon fibers or stainless steel fibers, conductive multifilament yarns cannot be electrospread, so these multifilament yarns cannot be mixed together. This is carried out by passing the fibers through an entangling treatment nozzle to mix and entangle the fibers.

[Problem to be solved by the invention]

A molded product in which the amount of deformation when making a molded product is not limited, the base resin penetrates well between the reinforcing fibers, the base resin and the reinforcing fibers adhere well, and the base resin is sufficiently reinforced by the reinforcing fibers. The molding method uses thermoplastic fibers for the base material resin, and in particular, it uses thermoplastic multifilament yarns, which are easy to make mixed fiber fabrics, mixed fiber yarns, etc. However, conventional thermoplastic multifilament yarns are coated with oil during the spinning process, as described above. If a thermoplastic multifilament yarn to which an oil agent has been applied is used for the base resin, the oil agent will deteriorate the performance of the base resin, and
Since it reduces the adhesive strength between the base resin and the reinforcing fibers, there is a problem in that it is difficult to obtain a molded product with excellent strength. Therefore, in order to obtain a molded article with excellent strength using conventional thermoplastic multifilament yarn, there is a problem in that an oil removal treatment is required at least before molding. Furthermore, conventional thermoplastic multifilament yarns are intended to be used in the form of fibers, such as as woven materials, and are made to have fiber strength and elongation at break that suit that purpose. When used as fibers for the matrix resin, the molded product may warp or distort, and even when melted, it is difficult to penetrate between the reinforcing fibers, making it impossible to achieve sufficient adhesion between the reinforcing fibers and the matrix resin.
Therefore, there is a problem in that a molded product with excellent strength may not be obtained easily.

The present invention has been made to solve the above-mentioned problems, does not require oil removal treatment, is easy to handle until molded products are obtained, and is easy to spread to make a mixed yarn with reinforcing fibers. Even when reinforcing fibers are used, the fibers can be opened by frictional charging without using a high-voltage electrode, and when melted, they easily enter between the reinforcing fibers.
The purpose of the present invention is to provide a multifilament system for a molded product base material resin that has excellent adhesion to reinforcing fibers and can yield molded products with excellent strength.

[Means to solve the problem]

The present invention is a multifilament system obtained by melt-spinning or further drawing a thermoplastic polymer, in which substantially no wood removal is applied during the spinning process, and the primary yield stress is 0. The present invention is a multifilament yarn for molded product base material resin, characterized in that the elongation at break is 45% or more and 100% or less at 8 g/de or more, and this structure achieves the above object.

In the present invention, most chain polymers that can be melt-spun are used as thermoplastic polymers, but polyarylene ether ketone (polyether Ketone, polyetheretherketone, polyetherketoneketone, polyetheretherketoneketone, etc.), polyetherimide, polyphenylene sulfide, and polyarylene sulfide are preferably used. These polymers have a glass transition point Tg'C in the range of 780-220'C and a melting point Tg'C in the range 780-220'C.
It has a m°C in the range of -345 to 400°C, is crystalline, has excellent impact resistance, fatigue resistance, chemical resistance, etc., and is not hygroscopic, and is preferred as a base material resin for molded products.

Melt spinning of thermoplastic polymers is usually performed at Tm+20 to 8
This is carried out by winding at a spinning temperature of 0°C and at a spinning speed that provides high productivity within a range where yarn breakage does not occur. In particular, in the case of polymers with poor spinnability, the spinning temperature should be lowered to avoid thermal decomposition and gelation as much as possible, and the spinning speed should be lowered to avoid yarn breakage, even at the cost of some productivity.

In order to improve spinnability, water may be applied to the yarn in the spinning process as described above, but an oil agent is not applied as is done in the conventional spinning process. The yarn obtained by the spinning process is called undrawn yarn (UDY), and has a primary yield stress lower than 0.8 g/de and a breaking elongation of 1.
Such yarns, which often have a low degree of molecular orientation greater than 0.00%, are then drawn to a primary yield stress of 0.8 g.
/de or more, and the elongation at break must be in the range of 45 to 100%. However, depending on the type of polymer and spinning conditions, it is possible to obtain a spun yarn having a primary yield stress of 0.8 g/de or more and a breaking elongation of 45 to 100%. As a spinning method for obtaining such a spun yarn with improved orientation, it is possible to use a spinning method that increases the orientation of the spun yarn by changing the spinning temperature and spinning speed, which is known for high-speed spinning of polyethylene terephthalate. Good, - Increasing the orientation of the spun yarn can be done under the same spinning conditions by increasing the molecular weight of the chain polymer, or by lowering the spinning temperature within a range that does not worsen the process condition. It is possible and
This can also be achieved by increasing the spinning speed. Therefore, in order to obtain spun yarn with high productivity and improved orientation, it is advantageous to increase the spinning speed. If such a spinning method can be employed and a spun yarn satisfying the above-mentioned conditions can be obtained, stretching may not necessarily be performed.

The spun yarn is drawn by heating the yarn in a hot water bath or a steam chamber and stretching it at an appropriate stretching ratio to achieve a primary yield stress of 0.8 g/de or more and 45 to 1
The stretching temperature at which the yarn is heated is higher than the Tg'C of the polymer, which is conventionally known as the -m stretching temperature.
(Although it may be selected appropriately from a lower range than
) has a Tg'C of 80 to 85°C, but the IJDY of this polymer can be sufficiently drawn at a temperature in the range of 70 to 90°C, including temperatures below Tg'C, yielding yarn that satisfies the above conditions. and polyetheretherketone (PI
! EX) has a Tg'C of 145°C, but it can also be fully stretched in warm water at 90 to 98°C.
Furthermore, polyetherimide (PEI) has a Tg''C of 1'217°C, which can also be fully stretched in hot water at 95 to 98°C.Stretching is performed under heating with hot water or steam as described above. Although this is preferred, the process is not limited to this and may be carried out in air. However, like the spinning process, an oil agent must not be applied in the drawing process.

The multifilament yarn of the present invention obtained by spinning or further drawing as described above has a single fiber denier of 1
~40de, preferably 1~15de, to suitably match the yarn denier to the yarn denier of the reinforcing fibers.If the single fiber denier is less than lde, fuzz or single fibers will form during spinning, drawing, or subsequent processes. Fiber breakage is likely to occur, and air bubbles are difficult to escape during molding and melting. It becomes difficult to obtain a mixed fiber yarn, and the ability to penetrate between reinforcing fibers during molding and melting becomes poor. Regarding yarn denier, the volume fraction of reinforcing fibers in the molded product, that is, the ratio of the volume of reinforcing fibers (value divided by weight by density) to the volume of molded product (value divided by weight by density) is 40~ 7
Since a range of 0% is preferable, it may be determined based on the yarn denier of the reinforcing fibers so that such a volume fraction can be easily obtained.

[For production]

Since the multifilament yarn of the present invention as described above does not have any oil attached, when it is spread and mixed with the multifilament yarn of reinforcing fibers, it can be opened by frictional charging without using a high voltage electrode, and therefore This has the effect of making yarn manufacturing equipment cheaper and improving work safety. In addition,
In this case, the multifilament yarn of the insulating reinforcing fiber should also be free from oil or the like.

Furthermore, since the multifilament yarn of the present invention does not have oil attached to it, when it is used together with reinforcing fibers to become the base resin of molded products, the oil will thermally decompose due to heating and gas will be generated. This has the effect that the material resin does not deteriorate or the adhesive strength of the base material resin to the reinforcing fibers does not decrease.

Moreover, the multifilament yarn of the present invention has a weight of 0.8 g/d.
Since it has a degree of orientation that shows a primary yield stress of e or more and a breaking elongation of 45% or more, when it is made into a mixed fiber yarn with a multifilament yarn of reinforcing fibers using an entangling treatment nozzle, it can be used alone to form a fabric such as a woven or knitted fabric. It is easy to handle without the need for sizing, etc. when making a fabric by interweaving with reinforcing fibers, when winding it around a mold with multifilament yarn of reinforcing fibers using the filament winding method, etc., and it is a uniform mixed yarn. Wrapping the fabric twice has the effect that the condition etc. can be obtained. For this, the primary yield stress is 0.8 g
If it is lower than /de, the multifilament yarn is likely to be stretched due to the tension applied in the process of blending, manufacturing, etc., and as a result, uneven tension causes differences in yarn length, resulting in loops and hanging, resulting in an uneven yarn. The condition cannot be obtained with mixed fiber yarn or one wrap of fabric.

On the other hand, if the elongation at break is lower than 45%, it means that the degree of orientation of the chain polymer in the fiber axis direction is high, and since such highly oriented fibers have high strength, the elongation at break is several times higher. %
Except for cases where the temperature is extremely low as mentioned below, the ease of handling in each of the above-mentioned processes is good, but when heated and melted to form the base resin of a molded product, there is large shrinkage and poor flowability. For this reason, voids are created between the reinforcing fibers,
It is easy to cause warping or distortion in the molded product.

The multifilament yarn of the present invention has a breaking elongation of 4.
Since it is 5% or more and 100% or less, it does not shrink when melted to make the base material resin, has good flowability, penetrates between reinforcing fibers and has strong adhesive strength with reinforcing fibers, and has excellent This has the effect that a molded product can be obtained. On the other hand, those with a breaking elongation of more than 100% have a low degree of orientation and less shrinkage during melting and have good flowability and penetration between reinforcing fibers. If the reinforcing fibers are used, the adhesive force with the reinforcing fibers may be weak, and the reinforcing fibers may not sufficiently reinforce the base resin. The reason for this is unknown, but considering that this tendency is particularly strong when the thermoplastic fiber is a crystalline polymer, the orientation in the fiber state remains even when melted,
This acts to improve crystallization on the surface of the reinforcing fibers, and as a result, the adhesive strength with the reinforcing fibers improves. However, in the case of low-orientation materials with a breaking elongation exceeding 100%, This is thought to be because crystallization on the fiber surface does not improve.

In addition, in order to fully exhibit the effects of the multifilament yarn of the present invention as described above, it is necessary that the reinforcing fibers be free from oil, size, etc., at least before being used together with the multifilament yarn of the present invention. If oil, size, etc. are used, they can be removed by cleaning or thermal decomposition.

It is also important that the reinforcing fibers do not undergo thermal decomposition or strength deterioration at a forming temperature comparable to the melt spinning temperature of the multifilament yarn of the present invention.

Therefore, when the multifilament yarn of the present invention is made of PEEK or PEI, which require a high molding temperature, carbon fiber or ceramic fiber is preferably used as the reinforcing fiber. A molded product made by using the PEEK multifilament yarn of the present invention as the base resin and reinforced with the above-mentioned reinforcing fibers,
PEEK's heat resistance, flame retardance, low moisture absorption, and mechanical properties such as bending strength, compressive strength, and fatigue resistance are much superior to those of thermosetting composite molded products, so it is used as a primary structural material for aircraft-related products. I can do it. In addition, molded products using PEI's multifilament yarn of the present invention as the base resin also have a high oxygen limit index of 45 to 47 and heat resistance of Tg'C.
It has a high temperature of 210°C, which is better than thermosetting resins currently in general use, so it is suitable for use in aircraft interior materials that require flameproofing and flame retardancy.

〔Example〕

The present invention will be further explained below with reference to Examples.

Example 1 Using a flow tester, the temperature was 320'C and the shear rate was 100.
PP whose melt viscosity measured at 0/sec is 1050 voids
S was applied with water at a melting temperature of 330°C, a spindle temperature of 318'C, and a spinning speed of 600+n/min, and wound up at 1800°C.
de/100fil (7) Undrawn yarn (uoy) was obtained. Kono uoy was stretched at a stretching ratio of 2 times in a 75'C (7) hot water bath and wound into a cheese shape at a speed of 200 m+/sin without twisting. The obtained drawn yarn was thoroughly dried in a dryer at 50°C. This multifilament yarn is
900de/100ft1, primary yield stress 0.98g
/de, and the elongation at break was 55%.

This yarn and Toshi ■ trading card 7"-300, which is a 3000 filament carbon fiber multifilament yarn, were used for 35 minutes.
The threads were heated at 0°C for 20 minutes to remove deposits such as sizing agents by thermal decomposition, and then each thread was taken out without twisting, stacked on a feed roller, and then passed between the feed roller and a delivery roller with the same feeding speed. The PPS yarn was brought into contact with a 10 mmφ alumina round rod at a contact angle of 120' and opened by frictional charging. At this time, along with the opening of the PPS yarn, the carbon-based yarn also opened slightly. The yarn that came out of the delivery roller was wound up by a winding machine, and the yarn that was taken up was a mixed fiber yarn with a considerable amount of PPS fibers interwoven between the carbon fibers.

A plain woven fabric with a basis weight of 300 g/mt was made by using this mixed yarn for the warp and weft without sizing. 10 pieces of this plain woven fabric were stacked in the same direction and weighed 15 kg/c.
11" pressure from room temperature to 320'C.
Raise the temperature in 5 minutes, hold at 320°C for 5 minutes, then lower to 50°C
The mixture was cooled for 20 minutes to obtain a flat plate molded product. This molded product has no warping or distortion (the surface is smooth, no holes are observed inside, and the three-point bending strength according to the measurement method of JIS K 6911 is 130 kg/w in the warp direction and 125 kg/w in the weft direction.
The molded product had a carbon fiber volume fraction of about 59%.

Example 2 PEEK of 150G was melted at a melting temperature of 395 to ε manufactured by IC1.
°C 2 Base temperature 384 °C 1 Winding speed 400 m/mi
It was wound up while applying water with n. The obtained U[lY
was stretched 1.8 times in a hot water bath at 97°C and wound without twisting. This drawn yarn is dried in a dryer at 60°C.
Dry for 0 minutes. This thread is 860 de/300fi
l, primary yield stress 1.4g/de, breaking strength 2.7
g/de, and elongation at break was 64%.

A plain woven fabric with a basis weight of 295 g/vr" was made in the same manner as in Example 1, except that this yarn was used in place of the PPS yarn in Example 1. Ten pieces of this plain woven fabric were laminated in the same direction, and 15
390° from room temperature when compressed with a pressure of "kg/cm"
The temperature was raised to C in 25 minutes, the pressure was increased to 25 kg/cm'', and the temperature was held at 390°C for 6 minutes, and then the molded plate was taken out after being cooled to 120°C over 25 minutes. There was no warping or distortion, the surface was smooth, and no air bubbles were observed inside.This molded plate had a three-point bending strength of 142 kg/ffIm" (warp), 1 latitude (width 1) according to JIS K 6911 method.
38 kg/mm'' and had excellent mechanical properties.

〔Effect of the invention〕

The multifilament yarn of the present invention can be suitably used to obtain molded products reinforced with reinforcing fibers, and can produce molded products with excellent strength without warping or distortion, without internal air bubbles, and at a relatively low cost. It produces the effect that can be achieved.

Note that the multifilament yarn of the present invention is not limited to the example in which it is used together with reinforcing fibers, but may be used alone in forming a molded article.

Claims (1)

[Claims] A multifilament yarn obtained by melt spinning or further drawing a thermoplastic polymer, in which substantially nothing other than water is added during the spinning process, and the primary yield stress is 0.8 g/de or more. A multifilament yarn for a molded product base material resin, characterized in that the elongation at break is 45% or more and 100% or less.