JP2009155363A - Manufacturing method for long fiber-reinforced thermoplastic resin material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method for obtaining a long fiber-reinforced thermoplastic material capable of reducing defective molding such as gas burning and mold deposit, at high productivity. <P>SOLUTION: This manufacturing method for the long fiber-reinforced thermoplastic material is a method for manufacturing the long fiber-reinforced thermoplastic material containing a constitutive element A of a reinforcing fiber bundle, a constitutive element B, that is a thermoplastic polymer having a fusion viscosity lower than a constitutive element C, having 200-10,000 of weight-averaged molecular weight, and the constitutive element C of a thermoplastic polymer having 10,000 or more of weight-averaged molecular weight, and arranged to bring the constitutive element C into contact with a composite containing the constitutive element A and the constitutive element B, and includes the first process for impregnating the constitutive element B fused heatedly at the temperature where the fusion viscosity of the constitutive element B comes to 10 Pa s or less and where a weight holding rate when heated for one minute gets to 95% or more, into the constitutive element A to from a composite, the second process for heat-treating the composite at a temperature higher by 50-150°C than a fusion temperature of the constitutive element C, and the third process for arranging the fused constitutive element C to contact with the composite. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a long fiber reinforced resin material produced from continuous fibers and a thermoplastic resin. More particularly, the present invention relates to a method for producing a long fiber reinforced resin material in which reinforcing fibers can be easily dispersed in a molded product when molding is performed by injection molding or the like, and molding defects such as mold deposits are small.

  A long fiber reinforced thermoplastic resin material in which a continuous fiber bundle is efficiently impregnated with a thermoplastic resin has drastically improved the physical properties of the thermoplastic resin and has dramatically expanded the range of use as a resin. The manufacturing method of the long fiber reinforced thermoplastic resin material is to mechanically dispose the molten resin between the fibers by adding fibers such as opening or squeezing the fiber bundle immersed in the molten resin or applying pressure to the resin. In general, a pultrusion method for impregnating the material is used. However, when trying to satisfactorily impregnate a continuous fiber bundle with a high-viscosity thermoplastic resin that exhibits high mechanical properties, the pultrusion method requires a very low fiber take-up speed, resulting in low productivity. Is a problem. In addition to this, a continuous fiber bundle is impregnated with a solution obtained by diluting a thermoplastic resin with a solvent to reduce the viscosity, and the solvent is removed in the next step, or a continuous fiber obtained by emulsifying and dispersing a thermoplastic resin. Manufacturing methods such as a method of removing the solvent after impregnating the bundle have been proposed, but none of them has improved productivity compared to the pultrusion method.

For such a situation, a technique for improving the impregnation property of the thermoplastic resin by modifying the fiber surface has been proposed. Patent Document 1 describes a method of impregnating a high molecular weight thermoplastic resin after disposing a thermoplastic polymer having a low molecular weight and low melt viscosity compatible with the high molecular weight thermoplastic resin on the fiber surface. Has been. According to this method, it is possible to obtain a resin material having higher mechanical properties and higher production efficiency than the manufacturing method described above. However, when the resin material obtained by this method is molded by injection molding or the like, the low molecular weight substance contained in the thermoplastic polymer is vaporized in the plasticizer and / or inside the mold, and gas is burned on the surface of the molded product. In many cases, molding defects occur, such as the occurrence of mold deposits and mold deposits in the mold.
Japanese Patent Laid-Open No. 10-138379

  An object of the present invention is to provide a method for producing a long fiber reinforced thermoplastic resin material that can provide a molded product with high mechanical properties and high quality with high productivity. Specifically, the present invention provides a method for producing a long fiber reinforced thermoplastic resin material that facilitates dispersion of reinforcing fibers into a molded product when molding by injection molding or the like, and does not easily cause molding defects such as mold deposits. For the purpose.

As a result of intensive studies to solve the above problems, the present inventors have found that this can be achieved by the following production method. That is, the above problem is
(1) Component (A) which is a reinforcing fiber bundle, Component (B) which is a thermoplastic polymer having a weight average molecular weight of 200 to 10,000 and a melt viscosity lower than that of component (C), and a weight average The component (C) is a thermoplastic resin having a molecular weight of 10,000 or more, and the component (C) is disposed in contact with the composite including the component (A) and the component (B). A method for producing a long fiber reinforced thermoplastic resin material comprising:
The component (B) is heated and melted at a temperature at which the melt viscosity of the component (B) is 10 Pa · s or less and the weight retention when heated for 1 minute is 95% or more. A first step of impregnating the composite to form a composite, a second step of heat-treating the composite at a temperature 50 to 150 ° C. higher than the melting temperature of the component (C), and then the molten component (C) A method for producing a long fiber reinforced thermoplastic resin material, comprising a third step of placing the composite in contact with the composite.
The solution is achieved.

  Moreover, according to the preferable form of this invention, it is also a preferable aspect that the following invention is included.

  (2) The method for producing a long fiber reinforced thermoplastic resin material as described in (1) above, wherein the component (B) is a phenol resin.

  (3) The method for producing a long fiber reinforced thermoplastic resin material according to (1) or (2), wherein the component (A) is a carbon fiber bundle.

  (4) The component (C) is one or a mixture of two or more selected from polyamide resins, polyester resins, polyphenylene sulfide resins, and styrene polymers. The manufacturing method of the long fiber reinforced thermoplastic resin material in any one.

  The present invention makes it possible to obtain a high-quality long fiber reinforced thermoplastic resin material with high productivity and high mechanical properties.

  Hereinafter, the present invention will be described in detail. First, components according to the present invention will be described.

  The component (A) is a reinforcing fiber bundle. The reinforcing fiber is not particularly limited as long as it is generally called a reinforcing fiber. For example, carbon fiber, glass fiber, metal fiber, aramid fiber, or a combination thereof can be used. Further, it is preferable to use continuous fibers such as roving and yarn as a continuous reinforcing fiber bundle. Among these, carbon fibers that are lightweight and highly rigid are preferably used from the viewpoints of physical properties and mechanical properties of the resin material obtained in the present invention.

  The component (A) is preferably blended in an amount of 5 to 50% with respect to 100% by weight of the long fiber reinforced thermoplastic resin material to be produced. If it is less than 5% by weight, the improvement of the mechanical strength of the resin material obtained in the present invention may be small, and if it exceeds 50%, the fluidity of the resin material may be deteriorated.

  The component (B) is a thermoplastic polymer having a weight average molecular weight of 200 to 10,000 and a lower melt viscosity than the component (C). When the component (B) is produced by forming a composite with the component (A), high productivity and high mechanical properties of the resin material are achieved. When the weight average molecular weight of the constituent element (B) is less than 200, the heat resistance is low, and thus it is easily vaporized and dissipated in the production method of the present invention, and the dispersibility of the fibers becomes low when the resin material is molded. There is. On the other hand, when the weight average molecular weight is 10,000 or more, the melt viscosity becomes high, so that the impregnation of the fiber bundle may be difficult. A more preferred weight average molecular weight is 200 to 5,000.

For the measurement of the weight average molecular weight described in the present invention, gel permeation chromatography (GPC) is used, and a low angle light scattering photometer (LALLS) using a laser as a detector is used. Moreover, the relationship of melt viscosity should just be the melt viscosity of a component (B) smaller than the melt viscosity of a component (C) in the temperature at the time of shape | molding a resin material. The melt viscosity described in the present invention is a viscosity at a temperature at a Vicat softening temperature + 30 ° C. or a melting point + 30 ° C. of a substance to be measured. When the substance is crystalline and has a clear melting point, the condition of melting point + 30 ° C. is adopted, otherwise the condition of softening temperature + 30 ° C. is used. The viscosity is measured by a JIS K7199 (1999) test method using a capillary rheometer. The shear rate in the measurement is 10 ³ s ⁻¹ . The Vicat softening temperature is measured according to the JIS K7206 (1999) test method. The melting point is measured by a differential scanning calorimeter (DSC) according to JIS K7121 (1987).

  The component (B) also preferably has a polar group. Examples of polar groups include amino groups, hydroxyl groups, and carboxyl groups. Moreover, it is also preferable to have a portion of an aliphatic hydrocarbon having a low polarity together with a polar group. Since the component (B) is arranged in the boundary phase between the component (A) and the component (C), if such a portion having a high polarity and a portion having a low polarity are combined, the component (B) also functions as a surfactant. In particular, it is preferable in that it contributes to the improvement of the dispersibility of the fibers in the resin during molding.

  Particularly, examples of the thermoplastic polymer that is excellent as the component (B) include phenolic resins such as phenol novolac resin, cresol novolac resin, terpene phenol resin, and phenol aralkyl resin. In addition, the component (B) includes a flame retardant, a weather resistance improver, an antioxidant, a heat stabilizer, an ultraviolet absorber, a plasticizer, a lubricant, a colorant, a compatibilizer, and a conductivity depending on the required characteristics. A filler etc. can be added.

  The component (B) is preferably blended in the range of 0.5 to 30% by weight with respect to 100% by weight of the long fiber reinforced thermoplastic resin material to be produced. If it is less than 0.5% by weight, the productivity of the resin material and the dispersibility of the fibers when molding the resin material may be reduced, and if it exceeds 30% by weight, the mechanical properties of the resin material may be deteriorated. More preferably, it can be used in the range of 2 to 15% by weight.

  The component (C) is a thermoplastic resin having a weight average molecular weight of 10,000 or more. If the weight average molecular weight is less than 10,000, the mechanical properties of the resin material obtained may be lowered. The component (C) is not particularly limited as long as the weight average molecular weight is 10,000 or more, but the melt viscosity is preferably 50 Pa · s or more and 1,000 Pa · s or less.

  The type of the thermoplastic resin of the component (C) is not particularly limited. For example, polyamide resins such as polyamide 6 resin and polyamide 66 resin, polyolefin resins such as polyethylene resin and polypropylene resin, polyethylene terephthalate resin, polybutylene terephthalate resin, etc. Polyester resins, polycarbonate resins, polyphenylene sulfide resins, polyphenylene oxide resins, polystyrene resins, liquid crystal polyester resins, styrene polymers such as ABS resins and AS resins, and the like can be used. A mixture of these may also be used. Moreover, what was copolymerized like the copolymer nylon of nylon 6 and nylon 66 may be used. Among these, polyamide resins, polyester resins, polyphenylene sulfide resins, and styrene polymers can be particularly preferably used from the viewpoints of mechanical properties, moldability, appearance of molded products, and the like. Furthermore, depending on the required properties of the molded product to be obtained, the component (C) includes a flame retardant, a weather resistance improver, an antioxidant, a heat stabilizer, an ultraviolet absorber, a plasticizer, a lubricant, a colorant, and a compatibilizer. A conductive filler or the like can be added.

  Next, the manufacturing method of the long fiber reinforced thermoplastic resin concerning this invention is demonstrated.

  The long fiber reinforced thermoplastic resin according to the present invention comprises a first step of obtaining a composite by impregnating the component (B) into the component (A), and the melting temperature of the component (C). It is manufactured through a second step in which heat treatment is performed at a temperature higher by 50 to 150 ° C., and a third step in which the molten component (C) is disposed in contact with the composite. Each step will be described below.

  In the first step according to the present invention, the component (B) is melted at a viscosity of 10 Pa · s or less, and the impregnation apparatus is heated and melted at a temperature at which the heated weight retention for 1 minute is 95% or more. This is a step of impregnating the component (A) using the application method described later to form a composite. By this step, it is possible to form a complex in which the component (B) is distributed almost uniformly throughout the component (A).

  Here, the melt viscosity of the component (B) is extremely low when impregnated at a temperature at which the melt viscosity is higher than 10 Pa · s. ) May be difficult to impregnate between the fibers, and the productivity of the resin material may be reduced. More preferably, heating to a temperature of 2 Pa · s or less is a more preferable aspect in that the resin is easily impregnated between the fibers.

  Further, when the component (B) is heated to a temperature at which the weight retention when the component (B) is heated for 1 minute is less than 95% (that is, when the weight loss when heated for 1 minute exceeds 5%), the component (B) is heated. Before impregnating (A), the low molecular weight substance in the component (B) is easily vaporized and released.

  Among the constituent elements (B), the low molecular weight material has a low kinematic viscosity and thus has a characteristic of being easily impregnated between the fibers. Therefore, it is considered that impregnation of the component (A) proceeds in order from a low molecular weight body to a high molecular weight body. In this way, when forming a complex from the component (A) and the component (B), when the low molecular weight substance was vaporized and released, the component (B) was distributed almost uniformly throughout the component (A). Since the formation of the composite becomes insufficient, the dispersibility of the component (A) may be reduced when a resin material described later is molded.

  In addition, the weight retention when heated is a value measured by a thermogravimetric analyzer (TGA) according to the JIS K7120 (1987) test method.

  As a method for applying the component (B) to the component (A) in the first step, a method such as applying an oil agent, a sizing agent, or a matrix resin to the fiber bundle can be used. As a more specific example, the molten component (B) is formed as a film having a constant thickness on the surface of a heated rotating roll (coating), and the component (A) is moved while contacting the roll surface. Thus, a method of attaching a predetermined amount of the component (B) to the component (A) can be mentioned. The coating of the component (B) on the roll surface can be realized by applying the concept of a known coating apparatus such as a reverse roll, a normal rotation roll, a kiss roll, a spray, a curtain, and extrusion. At the above temperature, the component (B) is applied to the component (A) to which the component (B) is adhered by operations such as ironing with a bar, repeating widening and focusing, and applying pressure and vibration. The inside of the fiber bundle as the component (A) is impregnated. As a more specific example, there is a method of performing widening by passing a fiber bundle in contact with the surfaces of a plurality of heated rolls or bars.

  The second step according to the present invention is a step of heat-treating the composite obtained in the first step at a temperature 50 to 150 ° C. higher than the melting temperature of the component (C). By this step, it becomes possible to remove the low molecular weight body of the excess component (B) from the complex in which the component (B) is distributed almost uniformly throughout the component (A), and the quality of the resin material obtained Improvement is possible. The melting temperature of the component (C) described in the present invention refers to the melting point when the thermoplastic resin is crystalline and has a clear melting point, and the Vicat softening temperature otherwise.

  When the heat treatment is performed at a temperature lower than 50 ° C. from the melting temperature of the component (C), the low molecular weight substance of the component (B) is not sufficiently vaporized and released. For this reason, when the obtained resin material is processed into a molded product by injection molding or the like, molding defects such as gas burning on the molded product or generation of mold deposit on the mold may occur. Further, when heat treatment is performed at a temperature higher than 150 ° C., the medium molecular weight body may be vaporized and released together with the low molecular weight body, and the dispersibility of the component (A) when molding the resin material is lowered. There is a fear. More preferably, the heat treatment is performed at a temperature 60 to 120 ° C. higher than the melting temperature of the component (C).

  When performing the heat treatment in the second step of the present invention, it is also preferable to add operations such as squeezing the composite with a bar, repeating widening and focusing, applying pressure and vibration, as in the first step. .

  In the third step of the present invention, the molten component (C) is disposed so as to contact the composite. More specifically, using an extruder and a coating die for the wire coating method, it is flattened by a method of continuously arranging the component (C) around the composite or by a roll or the like. An example is a method in which a film-like component (C) melted using an extruder and a T-die is disposed from one side or both sides of the composite and integrated with a roll or the like.

  The resin material obtained through such steps can be processed into a final product by a general molding method. The molding method is not particularly limited, and examples thereof include press molding, transfer molding, injection molding, and combinations thereof. The component (A) is almost uniformly dispersed in various target molded products. Further, it is possible to obtain a molded product in which the occurrence frequency of molding defects due to gas burning or mold deposit is reduced. Among these, when used for injection molding, the resin material may be cut into pellets by cutting to a certain length with an apparatus such as a pelletizer or a strand cutter. The length of the pellet is preferably in the range of 1 to 50 mm, which can facilitate the forming process, and more preferably 3 to 12 mm.

Hereinafter, although an example is given and the present invention is explained in detail, the gist of the present invention is not limited only to the following examples.
[Example 1] As a first step, a liquid film obtained by heating and melting a terpene phenol polymer (YP90L, manufactured by Yashara Chemical Co., Ltd., weight average molecular weight 460) was formed on a roll heated to 130 ° C. A kiss coater was used to form a film with a constant thickness on the roll. A continuous carbon fiber bundle (T300 manufactured by Toray Industries Inc., fiber system: 7 μm, number of carbon fibers: 12,000) is passed through the roll while making contact, and a certain amount of terpene per unit length of the carbon fiber bundle A phenolic polymer was deposited.

The carbon fibers to which the polymer was attached were alternately passed over 8 rolls with a diameter of 8 mm, which were heated to 130 ° C. and freely rotated by bearings, and arranged in a straight line. By this operation, the polymer was impregnated to the inside of the fiber bundle to form a continuous composite made of carbon fiber and terpene phenol polymer. At this stage, the amount of polymer relative to the entire composite was 15% by weight. The melt viscosity of YP90L at 130 ° C. at a shear rate of 10 ³ s ⁻¹ was about 1 Pa · s as measured by a capillary rheometer. Moreover, the heating weight retention of YP90L for 1 minute at 130 ° C. was 98% as measured by a thermogravimetric analyzer.

  Next, as a second step, the composite was heated to 290 ° C., freely rotated by a bearing, and passed alternately above and below six 50 mm diameter rolls arranged in a straight line. Here, the temperature of 290 ° C. is set to a temperature 70 ° C. higher than the melting point of 220 ° C. measured by the differential scanning calorimeter of the nylon 6 resin to be coated in the next step. By this operation, a continuous complex composed of the terpene phenol polymer from which the low molecular weight product was removed and the carbon fiber was formed. At this stage, the amount of polymer relative to the entire composite was 13% by weight.

Next, as a third step, the continuous composite was passed through a coating die for wire coating method installed at the tip of a single screw extruder having a diameter of 40 mm, and melted at 240 ° C. from the extruder into the die. Nylon 6 resin (“Amilan” (registered trademark) CM1017 manufactured by Toray Industries, Inc., weight average molecular weight 18,600) was discharged to continuously arrange the nylon 6 resin so as to cover the periphery of the composite. The melt viscosity of nylon 6 at 240 ° C. at a shear rate of 10 ³ s ⁻¹ was about 200 Pa · s as measured by a capillary rheometer.

  A resin material obtained by coating this composite with nylon 6 was cooled to near room temperature, and then pellets having a length of 7 mm were formed by a strand cutter. The molding material production up to this point was made by a continuous process, and the take-up speed of the carbon fiber bundle was 30 m / min. The composition ratio of the resin material was carbon fiber: terpene phenol polymer: nylon 6 resin = 33: 5: 62.

  Using this pellet, a flat plate molded product having an outer shape of 80 mm × 80 mm and a thickness of 1 mm was obtained by an injection molding machine having a clamping force of 100 t. During this molding, the cylinder temperature was set to 260 ° C. near the nozzle, and the mold temperature was set to 80 ° C. The surface of the molded product was smooth, there was no problem with the dispersibility of the fibers in the molded product, and no molding failure due to gas burning was observed. Further, although the molding was repeated continuously, generation of mold deposits was not recognized even after 1,000 shots were repeated.

In addition, the Izod impact value (with a notch) of this molded product (based on JIS K7110 (1999)) was 20 kJ / m ² .

  [Comparative Example 1] A pellet of resin material was obtained in the same manner as in Example 1 except that the second step of Example 1 was carried out at 180 ° C. The composition ratio of this resin material was carbon fiber: terpene phenol polymer: nylon 6 resin = 33: 6: 61.

  Using this pellet, a flat molded product having an outer shape of 80 mm × 80 mm and a thickness of 1 mm was obtained by an injection molding machine having a clamping force of 100 t. Although there was no problem with the dispersibility of the fibers in the molded article, slight gas burning was observed at the flow end portion. Further, when the molding was continuously repeated, generation of mold deposits was recognized in about 500 shots.

In addition, the Izod impact value (with a notch) of this molded product (based on JIS K7110 (1999)) was 20 kJ / m ² .

  According to the present invention, even if the molding process is continued using the resin material, molding defects are unlikely to occur, and a high-quality molded product can be manufactured.

Claims (4)

Component (A) which is a reinforcing fiber bundle, component (B) which is a thermoplastic polymer having a weight average molecular weight of 200 to 10,000 and a melt viscosity lower than that of component (C), and a weight average molecular weight of 10 And a constituent element (C) that is a thermoplastic resin that is equal to or greater than 1,000, and is configured such that the constituent element (C) is in contact with a composite that includes the constituent element (A) and the constituent element (B). A method for producing a fiber-reinforced thermoplastic resin material,
The component (B) is heated and melted at a temperature at which the melt viscosity of the component (B) is 10 Pa · s or less and the weight retention when heated for 1 minute is 95% or more. A first step of impregnating the composite to form a composite, a second step of heat-treating the composite at a temperature 50 to 150 ° C. higher than the melting temperature of the component (C), and then the molten component (C) A method for producing a long fiber reinforced thermoplastic resin material, comprising a third step of placing the composite in contact with the composite. The method for producing a long fiber reinforced thermoplastic resin material according to claim 1, wherein the component (B) is a phenol resin. The method for producing a long fiber reinforced thermoplastic resin material according to claim 1 or 2, wherein the component (A) is a carbon fiber bundle. The constituent element (C) is one or a mixture of two or more selected from polyamide resin, polyester resin, polyphenylene sulfide resin, and styrene-based polymer. A method for producing a fiber-reinforced thermoplastic resin material.