JPH0631821A - Manufacture of thermoplastic composite material - Google Patents

Abstract

PURPOSE:To produce thermoplastic composite material, the resin-impregnated state in which is favorable, at low cost and high speed by a method wherein the periphery of pre-impregnated matter is covered by highly viscous thermoplastic resin by employing a crosshead die having a straight die part and the resultant pre-impregnated matter is taken-off at the specified speed. CONSTITUTION:Pre-impregnated matter is produced by bringing the material concerned into contact with two or more rollers, which are installed normal to the fiber direction, at the temperature at which thermoplastic resin A such as modified polyolefin, polyamide or the like melts, and then take it off. Further, by employing a crosshead die having a straight die part, the periphery of the pre-impregnated matter is melted by being heated up to a temperature higher than that of the thermoplastic resin A. And, the periphery of the pre- impregnated matter is covered by thermoplastic resin B, the shearing viscosity of which is higher than that of the thermoplastic resin A at the same temperature and same shear rate as each other and which is compatible with the thermoplastic resin A under a molten state, such as polyethylene, polypropylene, polystyrene or the like. Next, the resultant matter is taken off at the speed of 20m/min or higher.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing a thermoplastic composite material. More specifically, the present invention relates to a method for producing a thermoplastic composite material produced by a melt drawing method in which a high production rate and a good impregnation state of a resin into a fiber are compatible with each other.

The thermoplastic composite materials produced according to the present invention have high cost / performance characteristics resulting from economic efficiency and good quality due to high production rates, so that they are suitable for automotive materials, electronic materials and aeronautical materials. It can be used in a wide range of applications as space materials, and can be put to practical use as a structural material or functional material.

[0003]

2. Description of the Related Art Fibers for industrial materials such as glass fiber, carbon fiber and aramid fiber can be used for industrial materials by taking advantage of their excellent characteristics of high elasticity and high strength. In this case, since these fibers alone cannot be used as a product having an arbitrary shape, they are usually molded by using a resin as a matrix. Such so-called composite materials have made remarkable progress as industrial materials in recent years.

The properties of composite materials are highly dependent on the properties of the matrix resin. The first step in the production of composite materials is to impregnate the fibers with a matrix resin. Conventionally, thermosetting resins (monomers, oligomers, prepolymers, etc.) have formed the mainstream as matrix resins from the viewpoint of ease of impregnation based on the low viscosity characteristic which is an essential feature. Well-known examples are glass fiber / unsaturated polyester used for housing materials, glass fiber / epoxy resin for printed wiring boards and the like, carbon fiber / epoxy resin for aircraft materials, and the like.

A composite material using a thermoplastic resin as a matrix has weaknesses such as difficulty of impregnation due to its high viscosity and molding requiring high temperature and high pressure, as compared with the above-mentioned thermosetting resin, but short molding time, In recent years, it has attracted attention due to various advantages such as storage stability of molding material (prepreg), high toughness of the obtained molded product, possibility of post-processing and repair, and recyclability. In particular, recyclability is very important from the viewpoint of protecting the global environment.

One of the most important factors that has led to the development of thermoplastic composite materials is the breakthrough in manufacturing technology centering on the impregnation of resin into fibers. In this case, what is important is that, in order to make the thermoplastic composite material usable as an industrial material, it must be a technique for producing a low-cost, high-quality material. In short, this is a balance between high production rate and good impregnation.

From the above viewpoint, many methods have been tried. Firstly, there is one in which the impregnation is carried out in the state of a solution or emulsion. Since these have low viscosities, the impregnation is good, but it is necessary to completely remove the solvent and water, the productivity is low, and the physical properties decrease due to their residual in the molded product poses a problem. The second is a method of using a polymer precursor such as a monomer, an oligomer or a prepolymer. This also has good impregnation, but requires polymerization to be performed, and the production rate is slow. Thirdly, the thermoplastic resin is introduced into the reinforcing fibers in the form of a film, powder, fiber or the like and then melted. With this method, a good impregnation state can be obtained, but generally impregnation time is long and it is necessary to remove bubbles. However, the method using the powdered resin can increase the production rate because the resin can be introduced into the fiber gap in a short time by the fluidized bed. In spite of such advantages, there are drawbacks in that bubbles are easily contained and the resin is limited to powder. Fourthly, the resin in a molten state is directly impregnated into the fiber, and the method is the most widely used because the method is simple and a composite material with few bubbles and good in the impregnated state can be produced.

As the method of using the molten resin, the lamination method and the drawing method are well known as the impregnation methods. In the former, the molten sheet-shaped thermoplastic resin and the fibers are superposed and then press-fitted. The latter utilizes a so-called pultrusion molding method which has been conventionally carried out with a thermosetting resin, and is a method for producing a composite material by introducing fibers into a molten thermoplastic resin and then withdrawing it through a die. The laminating method is, for example, JP-A-61-40113, JP-A-61-229534, and JP-A-61-
No. 229535, No. 61-229536, No. 64-61557, and No. 64-61.
No. 558, JP-A-64-61559, JP-A-64-61561, JP-A-64-61562, JP-A-2-48907, etc., but examples thereof The production speed is extremely slow as seen in. The drawing method uses a so-called low-viscosity molten resin bath (for example, JP-A-57-181852, JP-A-63-239032, JP-A-3-188131).
Japanese Patent Laid-Open No. 3-243308), but in recent years, a method of using a crosshead die attached to the tip of an extruder has been widely used.

Many proposals have been made for improving the impregnation property of resin in the melt drawing method using a crosshead die.
Of course, if the temperature is raised, the viscosity of the resin is lowered and the impregnation is improved, but the heat deterioration of the resin is severely undesirable. Therefore, the first one relates to the treatment of fibers, for example, heating the fibers before impregnation (Japanese Patent Laid-Open No. 3-47714, Japanese Patent Laid-Open No. 3-47714)
230943) and opening treatment (US Pat. No. 4588).
No. 538 and Japanese Patent Laid-Open No. 63-264326). However, it is difficult to greatly improve the production speed in any case. The second relates to an improved crosshead die, which has a pressure chamber (US Pat. No. 3,993,726), a barrier die (US Pat. No. 3,993,726, US Pat. No. 4,132,917, US Pat. No. 4,439,387). U.S. Pat. No. 4,588,538.
No. 63-264326), a die containing a roll or a rod (US Pat. No. 4,728,387, Japanese Patent Laid-Open No. 63-132036, Japanese Patent Laid-Open No. 3-1907, and Japanese Patent Laid-Open No. 3-183531). ), A die having a degassing port (JP-A-4-27507), and the like. Among these, the invention (US Pat. No. 3,993,726)
Japanese Patent Publication) discloses an example in which the production rate is high, but it is shown that the resulting composite material has low physical properties. Thirdly, a resin is attached to the fibers by using a die, and then pressure treatment is performed. A method using a heat roll (Japanese Patent Laid-Open Nos. 59-62114 and 60-361).
No. 36) has been tried, but it is stated that the production speed is at most about 10 m / min.

In addition to the above-mentioned invention in terms of the apparatus, the resin impregnation property in the melt drawing method from the material side has been improved. These mainly use fibers bundled with a special sizing agent (JP-A-3-181528).
JP-A No. 3-121146), plasticizers (JP-A-59-47233 and JP-A-59-47), which use a matrix resin having a high affinity for fibers.
234, JP-A-3-115327) and liquid crystal polymers (US Pat. No. 4,386,174, US Pat. No. 4).
No. 433083, U.S. Pat. No. 4,438,236) to lower the viscosity of the resin and a blend of specific resins (Japanese Patent Laid-Open No. 3-6256), but high productivity cannot be achieved by either method. .

In the technique of producing a thermoplastic composite material by the melt drawing method using a black head die, the purpose is to obtain good impregnation of the resin into the fiber (Japanese Patent Laid-Open No. 61-236).
No. 832, Japanese Patent Application Laid-Open No. 1-317751) and the purpose of preventing fuzz at the die exit (Japanese Patent Application Laid-Open No. 3-2728).
So-called two-step process is disclosed in Japanese Patent No. 30). This is because the fiber is impregnated with the first resin by the crosshead die in the first step, and then the crosshead die is used again in the second step to make the impregnated material obtained in the first step It coats the resin of No. 2. Where the first
The resin and the second resin may be the same (Japanese Patent Laid-Open No. Hei 3 (1999) -311 (1999)).
However, different ones are generally used (however, both have compatibility). That is, the first
Resins with low viscosity and affinity for fibers,
The resin of (1) has a high molecular weight that forms a so-called matrix and has excellent physical properties (JP-A-61-236832 and JP-A-1-3177751). Further, as the crosshead die used in the first step (impregnation), one having a convex barrier passage is disclosed. The first
And the second step is shown to be performed continuously. Such a two-step process method allows the production of composite materials with excellent physical properties in order to produce good impregnation. However, under the high-speed take-up condition, the yarn breakage at the barrier is unavoidable, and there is a fatal defect that the production rate is slow as disclosed in those examples.

[0012]

As described in the section of the prior art, as a technique for producing a thermoplastic composite material, a high-quality composite material based on a good resin-impregnated state containing no air bubbles inside has been used so far. Moreover, there was no way to manufacture at a high production rate.

Therefore, an object of the present invention is to provide a method for producing a thermoplastic composite material which achieves both the productivity and the quality, which should be said to be a problem of the prior art.

[0014]

The rate-limiting factor in the production of composite materials is the process of impregnating fibers with resin. This is particularly remarkable in the case of a thermoplastic resin having a high viscosity. The speed of the impregnation step is the length of the impregnation step divided by the time required for impregnation, but lengthening the step is not preferable from the point of view of equipment cost, so speed up by shortening the time required for impregnation. I have to figure it out.

To reduce the impregnation time, it is necessary to increase the impregnation rate. It is well known that Darcy's law represented by the following mathematical formula is usually applied to the impregnation rate (V) of the resin into the fiber. Therefore, in order to increase the impregnation speed, it is necessary to increase the transmittance (for example, opening the fiber), decrease the resin viscosity, and pressurize.

[0016]

[Formula 1]

The present invention uses an extruder for 10 ² sec ^-1.
Has a shear viscosity of 1 to 20 Pascal · sec, and
A cloth in which a thermoplastic resin having a polar group having a chemical affinity with a functional group on the fiber surface in a main chain skeleton or a side chain (hereinafter, referred to as "thermoplastic resin A") is linearly crossed After pulling out the continuous reinforcing fiber through the head die, at a temperature at which the thermoplastic resin A is melted, the continuous reinforcing fiber is wound around at least two or more cylindrical free-rotating rollers placed perpendicular to the fiber direction to be taken up and pre-impregnated. Of the pre-impregnated product by using a crosshead die having a linear die part.
A thermoplastic resin that melts at a higher temperature than the above, has a higher shear viscosity than the thermoplastic resin A at the same temperature and the same shear rate, and is compatible with the thermoplastic resin A in the molten state (hereinafter, "Thermoplastic resin B"), and at least 2
It is a method for producing a thermoplastic composite material, characterized in that the thermoplastic composite material is collected at a speed of 0 m / min or more.

That is, according to the present invention, the thermoplastic composite material manufacturing process is divided into two processes, an impregnation process for producing a pre-impregnated product and a coating process for producing a final target product from the obtained pre-impregnated product. As described above, the speed of the impregnation process, which is the rate-determining process, is speeded up in order to speed up the whole process.

The impregnation step described in the present invention means that continuous reinforcing fibers are drawn out through a crosshead die in which the thermoplastic resin A is supplied by an extruder, and then the thermoplastic resin A is melted at a temperature in the fiber direction. The pre-impregnated product is manufactured by wrapping it around at least two or more vertically rotating cylindrical freely rotating rollers.

In FIG. 1, the continuous reinforcing fiber 2 delivered from the creel 1 is guided to a preheat treatment device 4 via a guide roll 3. The creel is required to have a function of controlling the tension of the fibers to be fed. Especially in the case of producing a composite material at a high speed, the tension must be set so that the yarn is not broken at the same time as the impregnation property is improved. Further, the guide roll is for introducing the fiber supplied from the creel into the preheat treatment apparatus, and it is necessary to devise it so that fluff does not occur. It is necessary to consider the shape (diameter and width) and surface condition (ceramic, Teflon surface, etc.) that will reduce the frictional resistance as much as possible. Further, a roll which has a low rotational resistance and can freely rotate is preferable. The preheat treatment is carried out for the purpose of preventing deterioration of impregnation characteristics of the resin by removing volatile substances such as water adhering to the fiber and preventing increase in viscosity due to decrease in resin temperature at the time of contact with the fiber. The temperature is selected according to the boiling point of the attached volatile substance and the impregnation temperature of the resin, and is selected in consideration of the heat resistance (melting temperature and thermal decomposition temperature) of the fiber treating agent (mainly sizing agent). Therefore, depending on the fiber / resin combination, for example, in the case of glass fiber / polypropylene, 120 to 230 ° C, preferably 140 to 200 ° C.
Is. The treatment time varies depending on the treatment temperature and the type of fiber (heat conductivity), but is about 10 seconds to 1 minute. As a heating method, a hot air method is generally used, but an infrared radiation method is more preferable because it disturbs the bundled state of fibers. When a fiber treatment agent that is easily decomposed by heat is used, it is preferably performed in an inert gas atmosphere.

Examples of the continuous reinforcing fiber used in the present invention include glass, carbon, aramid, polyethylene, polypropylene, nylon, polyester, polyphenylene sulfide, polyether ether ketone, liquid crystal polymer, organic polymer fiber such as polyimide, alumina, Inorganic fibers such as silicon carbide and silicon nitride, and metal fibers such as stainless steel are included. Note that a combination of two or more of the above may be used.

There are no particular restrictions on the diameter or the number of bundles of these fibers. Generally, the diameter is 4 to 20 μm and the number of bundles is about 1000 to 15000. They are,
It is selected in consideration of the impregnation property of the resin and the physical properties of the composite material. In the present invention, such tow (a bundle of a large number of monofilaments) is optimal, but other woven fabrics can also be used. However, in particular the use of one tow is the most preferred embodiment. The fiber is usually treated with a treating agent. The most important treatment agents are surface treatment agents and sizing agents. As the surface treatment agent, silane coupling agents for glass fibers are known, but various coupling agents are used. These chemically bond to the fiber surface and dramatically improve the chemical affinity with the matrix resin, thereby significantly improving the physical properties of the composite material. The types of them depend on the chemical structure of the resin used, and the throughput cannot be generally stated, but in general fiber 1
0.01 to 1 part by weight, preferably 0.05 to 1 part by weight
0.5 parts by weight. The sizing agent bundles a large number of fibers to improve the handleability thereof, and plays a very important role at the time of producing a composite material at a high speed, which is the gist of the present invention. That is, it is necessary to prevent the unwinding of the fiber from the creel at high speed and the damage of the fiber when the guide roll rubs. As the sizing agent, a polymer having compatibility with the matrix resin is usually used. What is important is the amount of adhesion, and if it is too small, the above fiber protection effect cannot be exhibited, and if it is too large, the impregnation property of the resin is reduced. In many cases, it is about 0.1 to 1 part by weight with respect to 100 parts by weight of the fiber. Further, one of the important requirements that the continuous reinforcing fiber used in the present invention has is that the twisting is small, and if possible, it is not necessary. Twisting causes poor impregnation and must be avoided. For this reason, so-called compound yarn roving, which is produced by combining several fibers together, is not suitable because it easily contains twist. Also, when releasing the fibers from the bobbin when unwinding, it is desirable to release the fibers from the outside where twisting is less likely to occur. When releasing inside, it is necessary to devise so that twisting does not occur.

Regarding the positional relationship between the creel, the guide rolls and the preheat treatment device, it is preferable that the distance between the creel and the guide rolls is as long as possible. The difference in tension applied to the fiber at the time of delivery from the center and end of the bobbin is reduced,
Impregnation is less likely to occur. Also, the yarn path blurring is small,
Good stability. The distance between the guide roll and the preheat treatment device is not particularly limited.

Next, the fiber exiting the preheat treatment apparatus 4 enters the crosshead die 17 to which the thermoplastic resin A6 is supplied by the extruder 5 and is drawn through it. The most common extruder is a single screw extruder, but it is also possible to use a twin screw extruder and equip a degassing device (vent) to prevent bubbles from being contained in the impregnated resin. Is also preferable. In order to make the composition of the obtained pre-impregnated material uniform, it is necessary to suppress the fluctuation of resin discharge as much as possible (especially in the case of high-speed production). I have to. From such a point, it is necessary to consider the shape of the resin, its uniformity, and the screw shape. It is also possible to use a feeder.

The crosshead die used in the present invention is
This type is similar to that normally used for wire coating molding (pressure die). As shown in FIG. 2, the molten resin sent from the extruder enters a manifold (resin reservoir) 8 provided to make the outflow amount uniform, and passes through a flow path 9 having a rectangular cross section. The fibers come into contact at the confluence 10. The guider chip 11 serves to prevent the molten resin from leaking from the rear part of the die and to hold the fiber at the center of the die. It is important to select the material because it comes into contact with hard fibers at high speed, and high hardness steel or the like is suitable. Further, the gap 12 (rectangular cross section) of the guider tip portion depends on the diameter of the fiber used and the number of bundles, and the clearance with the bundled yarn needs to be about 0.05 to 0.1 mm. However, even if the gap is tapered, it does not matter. If the gap is too narrow, yarn breakage will occur, and if it is too wide, resin leakage will occur. It can be said that the length of the guider tip portion is sufficient if it has a dimension capable of holding the fibers. The resin in contact with the fibers penetrates between the fibers in the slit-shaped die portion 13 having a rectangular cross section. Regarding the shape of the die portion used in the present invention, it is not suitable that the yarn breaks during high-speed production. In the case of a complicated curved shape such as a corrugated shape having a convex barrier, the effect of improving the impregnating property of the resin can be expected, but the high-speed extraction is impossible. A simple straight line with low resistance is desirable. However, it does not matter if it is tapered. Since the molten resin is contained and does not come into contact with the fiber itself, the material of the die portion is normally steel. The length of the die is determined by the cross-sectional shape (gap and width), resin viscosity and extrusion rate, take-up speed, and pressure loss. It is necessary to promote the penetration of The gap is
It depends on the diameter of the fiber used and the number of filaments. However, it must be taken into consideration that a narrow gap or a long die will increase the tension applied to the fiber and will easily break the yarn.

The temperature of the crosshead die must be above the melting temperature of the thermoplastic resin A used and below the thermal decomposition temperature. For polypropylene, for example, 15
0 to 230 ° C, preferably 160 to 200 ° C.

The thermoplastic resin A of the present invention must satisfy the following two conditions: (i) excellent impregnation into fibers and (ii) good wettability with the fiber surface. From the above (i) and (ii), it is necessary to have a polar group having chemical affinity with the fiber surface in the main chain skeleton or the side chain. The type and amount of the polar group are determined depending on the state of the surface functional group of the fiber used (particularly the type and amount of the surface treatment agent). Examples of the polar group include carbonyl, acid, ester, OH, ether, epoxy, halogen and amine. Further, from the above (ii), the melt viscosity of these resins is very important because it determines the impregnation rate.
The shear rate at the die portion of the crosshead die described in the present invention is generally on the order of 10 ² sec ^-1 , though it varies depending on the resin extrusion amount and die shape. The thermoplastic resin A used in the present invention has a melt viscosity of 1 in the shear rate range.
-20 Pa (Pascal) · sec, preferably 5-10 Pa ·
Seconds are preferred. If it is larger than 20 Pa · sec,
Impregnating property is not good. On the other hand, if it is less than 1 Pa · sec, the physical properties of the finally produced composite material are deteriorated, which is unsuitable. Examples of such thermoplastic resin A include low molecular weight polymers such as modified polyolefin, polyamide, polyester, polyphenylene sulfide, and polyether ether ketone. As the modified polyolefin, a polyolefin grafted with an unsaturated carboxylic acid such as maleic anhydride or itaconic acid or an unsaturated carboxylic acid ester such as 2-hydroxyethyl methacrylate or glycidyl methacrylate is well known, and aminosilane It is also known to be effective for glass fibers treated with a coupling agent or the like.

The thermoplastic resin A is selected according to the combination of the fiber used (particularly the surface characteristics) and the thermoplastic resin B described later. When using the thermoplastic resin A, various additives (for example, antioxidants), plasticizers, lubricants, fillers, etc. may be added to the extent that the characteristics thereof are not impaired.

At the melting temperature, the continuous reinforcing fibers to which the thermoplastic resin A has been attached in the crosshead die are wound around at least two or more cylindrical freely rotating rollers 14 placed perpendicular to the fiber direction. Taken off to give the pre-impregnate 15. In this case, it is preferable that the fibers exiting the crosshead die reach the rollers in the form of a molten bear in which the resin contained therein does not solidify in view of the overall production speed. Therefore, a short distance between the crosshead die and the rollers is preferred.

The roller used in the present invention is an apparatus for impregnating fibers with the thermoplastic resin A, and is particularly important. By wrapping around the roller and taking it up,
The fiber is under tension and is impregnated with the attached resin. In order to carry out the impregnation, it is an essential condition that the resin is in a molten state. For that purpose, by heating the roller itself with a heater or heating medium circulation, or by placing the roller in a tank heated by hot air or infrared rays,
The thermoplastic resin A can be melted. The temperature is equal to or higher than the melting temperature of the thermoplastic resin A to be used, and the higher the temperature is, the higher the impregnation rate can be expected due to the decrease in stickiness, which is preferable. For example, in the case of polypropylene, 150 to 200 ° C, preferably 150
~ 180 ° C. Therefore, it is also recommended to install the roller in an inert gas atmosphere.

In the step of impregnating fibers with a resin using the above roller, among the factors that control the impregnating property, those related to the roller are rotation (fixed or free rotation), Shape, surface friction coefficient, number, contact angle with fiber, etc. The selection of these factors is extremely important in order to obtain the high production rate and good impregnability which is the object of the present invention. First, regarding rotation and shape, it is an essential condition that it is a freely rotating columnar type. Fixed rollers and rollers having a spheroidal convex shape are known from the viewpoint of improving the impregnation property, but they are unsuitable because at the time of high speed, yarn breakage or fluffing easily occurs. It is also required to make the surface friction coefficient as small as possible, and the material of the roller must be selected in consideration of heat resistance. Since friction is only a problem on the surface, a method of coating a metal with ceramics, Teflon, or hard chrome may be used. Next, regarding the diameter, number, and contact angle, these must be selected from the best in terms of cost / performance (however, for the number, in order to tension the male salmon, at least two must be selected). Pieces are required). Generally, the larger the diameter, the larger the number, and the larger the contact angle (that is, the smaller the distance between the rollers), the larger the tension applied to the fiber and the better the impregnation property, but the more easily the yarn breaks. This tendency becomes more remarkable as the collection speed increases. Regarding the arrangement of the rollers, as shown in FIG. 3, their rotation axes may or may not be on the same straight line, and contact with the fibers by changing the distance between the rollers as shown in the figure. The corners can be controlled. The roller produces a pre-impregnated material in which fibers are impregnated with a resin, and the proportion of fibers in the pre-impregnated material of the present invention can be up to 80% by volume, preferably 60 to 75% by volume. The ratio of the thermoplastic resin A can be at least 20% by volume, but is preferably 25 to 40% by volume.
When the fiber ratio exceeds 80% by volume, the unimpregnated portion increases, which is not preferable. Further, when the value is less than 60% by volume, that is, the ratio of the thermoplastic resin A is more than 40% by volume, a large amount of the thermoplastic resin A which is a low molecular weight resin is present in the finally produced composite material. Becomes inconvenient in terms of physical properties.

The coating step described in the present invention is to coat the pre-impregnated product obtained in the above-mentioned impregnation step with a thermoplastic resin B around it using a crosshead die to obtain a thermoplastic resin as a final product. This is a process of manufacturing a composite material.

The pre-impregnated material 15 is introduced into the crosshead die 16 in a state where the thermoplastic resin A impregnated therein is molten. To the crosshead die,
The extruder 17 is supplying the thermoplastic resin B18. There is no particular limitation on the extruder used here, but it is desirable that the extruder has stable discharge characteristics in order to coat uniformly.

The structure of the crosshead die is basically the same as the structure of the crosshead die used in the impregnation step. As described above, the former is slit-shaped, but the shape of the crosshead die used here is arbitrary depending on the shape of the final product. The most common ones are slits and circles. Further, since the pre-impregnated material is impregnated with resin, the material of the guider tip portion is normally ordinary steel. Regarding the gap of the guider tip part, the same clearance as in the case of the crosshead die in the impregnation process is sufficient (the gap may be tapered), but regarding the length, the molten state of the resin in the pre-impregnated material A length that can be held is required. The pre-impregnated material is coated with the thermoplastic resin B around the die portion. The die part is preferably on a simple straight line as in the crosshead die in the impregnation step, which enables high-speed coating. (However, it does not matter if it has a tapered shape.) For high-speed production, it is necessary to increase the length of the die part and to perform coating uniformly. Further, the cross-sectional size of the die portion is determined by the desired final product size. For example, for the production of strands,
A circle of 3 mm has a width of 3 to 30 mm and a slit of 100 to 500 μm in the production of a tape, and a width of 200 to 1000 mm and a thickness of 100 to 500 μ in the production of a sheet.
A slit of m can be described as a representative example. It is necessary to consider that the shape of the die affects the tension of the fiber.

The temperature of the crosshead die must be above the melting temperature of the thermoplastic resin B used and below its thermal decomposition temperature. Further, as will be described later, the thermoplastic resin A is required to melt at a lower temperature than the thermoplastic resin B referred to here, and the thermoplastic resin A is inevitably produced at the temperature of the crosshead die. Is in a molten state. For example, when polypropylene is used as the thermoplastic resin B, 180 to 250 ° C., preferably 200 to 23
It is in the range of 0 ° C.

The thermoplastic resin B according to the present invention includes generally well known thermoplastic resins. Polyethylene, polypropylene, polystyrene, polyvinyl chloride,
Polymethylmethacrylate, nylon 6 and nylon 66
Polyamide such as, polyester such as polyethylene terephthalate and polybutylene terephthalate, polycarbonate, polyphenylene oxide, polyacetal, polysulfone, polyether sulfone, polyphenylene sulfide, polyether ether ketone, liquid crystal aromatic polyester, polyimide and their copolymers, modified Examples include the body and blends of two or more of the above. In selecting these thermoplastic resins B, the relationship with the thermoplastic resin A to be used, that is, (i) compatibility with the thermoplastic resin A in a molten state, (ii) higher than that of the thermoplastic resin A It must melt at temperature, (iii) have a higher shear viscosity than thermoplastic resin A at the same temperature and the same shear rate.
Examples of such a combination include low molecular weight modified polypropylene (A) / polypropylene (B), low molecular weight polyamide (A) / polyamide (B), and the like. The thermoplastic resin B has a higher melt viscosity than the thermoplastic resin A,
Generally 10 ² to 10 at a shear rate of 10 ² sec ^-1
The value is about ³ Pa · sec. When using the thermoplastic resin B, known additives, modifiers, fillers and the like may be added.

Since the thermoplastic resin A and the thermoplastic resin B are united to form the matrix of the composite material as the final product, the ratio of these two is very important.
In the present invention, the proportion of the thermoplastic resin B in the total of these two is 50 to 95% by volume, preferably 70 to 90% by volume. If this ratio is less than 50% by volume, the physical properties of the composite material (for example, strength in the direction perpendicular to the fiber, impact strength, heat distortion temperature, etc.) are adversely affected, which is not preferable. On the other hand, when the content is more than 90% by volume, the impregnation property to the fiber and the adhesive property at the fiber / resin interface are poor and it is difficult to obtain a good composite material. In the present invention, after the coating with the crosshead die, it is also possible to carry out a defoaming operation in order to completely remove the bubbles which are easily introduced into the product at that time. There are various defoaming methods, but it is necessary to use a method that does not impair the high-speed productivity, which is the gist of the present invention. From this, for example, the thermoplastic resin B
At the melting temperature of, the method of winding around at least two or more cylindrical free-rotating rollers placed perpendicular to the fiber direction is effective and preferable. Regarding the method for heating the roller and the resin, the same method and method as those used in the impregnation step can be used. The defoaming operation is preferably performed before the coated resin is solidified, and therefore it is preferable that the crosshead die and the defoaming device are as close to each other as possible.

After the pre-impregnated material is coated with the thermoplastic resin B by the crosshead die, it is cooled in the cooling device 19. For cooling, a known method such as a method of passing water, a method of contacting with a roll or plate whose surface is set at a solidification temperature or lower, a method of blowing cold air, etc. are used, and a method having high cooling efficiency is preferable.

The thermoplastic composite material produced according to the present invention is drawn and produced by the take-up device 20 at a constant speed. As the take-up device, a known device such as a nip roll or a caterpillar belt can be used, but it needs to be able to handle high-speed take-up. The maximum feature of the present invention is the take-up speed, in other words, the cattle production speed is at least 20.
Speeds of m / min and above are possible.

The take-up speed depends on the composition of the fiber, resin and composite material used. In short, the higher the impregnation speed and the less the fiber is damaged or cut, the faster the fiber can be taken. The take-up speed is also affected by the shape of the composite material. For example, the production of a wide sheet using a large number of bobbins requires a slow take-up speed as compared with the production of a tow prepreg using a single tow. However, even in such a case, the present invention can produce a composite material at a much higher speed than, for example, the conventional method.

As the method for producing the thermoplastic composite material of the present invention, in addition to the method of continuously performing the impregnation step and the coating step as described above (so-called on-line system), these two steps are separated. It is, of course, possible to adopt the method (so-called off-line method) which is performed by the above method. That is, in the off-line method, the pre-impregnated material produced in the impregnation step is once cooled and wound, then the wound pre-impregnated material is set on a creel and sent out, and a crosshead die is used. By carrying out the coating step, the final thermoplastic composite material is produced. The above-described cooling method and apparatus are the same as those in the case of cooling after the above-mentioned coating step. For delivery, the tension must be controlled to allow uniform coverage.
The production rate of the impregnation process in the off-line system can be the same as the production rate in the on-line system. On the other hand, the coating step can be performed at least at the same speed as or higher than the impregnation step.
As described above, the thermoplastic composite material produced by the present invention is composed of the continuous reinforcing fiber, the thermoplastic resin A, and the thermoplastic resin B. Regarding the usage ratio, the continuous reinforcing fibers are 15 to 65% by volume, preferably 20 to 60% by volume, and the total of the resin components of the thermoplastic resin A and the thermoplastic resin B is 35 to 85% by volume. %, Preferably 40 to 80% by volume. The ratio of continuous reinforcing fibers is 1
When it is less than 5% by volume, the thermoplastic composite material has low physical properties and has little practical value as a structural material. This ratio is 6
If it is more than 5% by volume, it is difficult to obtain a good impregnated state, which is not preferable. Regarding the ratio between the thermoplastic resin A and the thermoplastic resin B, as described above, the ratio of the thermoplastic resin B to the total amount of both is 50 to 95% by volume, preferably 70 to 90% by volume.

The thermoplastic composite material 21 produced by the present invention is a continuous long product having an arbitrary cross-sectional shape which is finally wound up by the winding device 22, but most commonly, a strand, a tape, For example, a sheet. The strand has a maximum diameter of about 1 to 3 mm, the tape has a width of 3 to 30 mm and a thickness of 100 to 500 μm, and the sheet has a width of 200 to 1000 mm and a thickness of 100 to 500.
A typical shape is about μm.

The thermoplastic composite material produced by the present invention can be provided as various molded articles by using various known molding methods. For example, a strand is cut into a suitable length (about 2 to 50 mm) into a pellet, which is then molded by injection molding, extrusion molding, press molding, or the like. Molded articles can also be manufactured by direct pultrusion or filament winding methods. Alternatively, it may be formed after being processed into a woven fabric, a knitted fabric, a braid, or the like. Tape-shaped ones, especially wide ones, can be formed by pressing or autoclaving after laminating. Further, the tape having a narrow width can be formed by the drawing method or the tape winding method as in the case of the strand, and it is also preferable that the tape is formed after textile processing such as woven fabric, knitted fabric and braid. After being laminated, sheet-like materials can be used by various sheet forming methods (eg, autoclave, hot press, stamping, diaphragm, etc.). Molding conditions such as temperature, pressure, time, etc. vary depending on the thermoplastic material (resin, fiber, composition, shape, etc.) used and the molding method used, so it cannot be said unequivocally, but fiber cutting, disorder of arrangement, voids The optimum conditions should be selected so as to obtain a good fiber dispersion state without deterioration of the resin. In particular, if the matrix resin is crystalline, the cooling conditions have a significant effect on its physical properties, so care must be taken.

[0044]

EXAMPLES The contents of the present invention will be described in detail below with reference to examples and comparative examples. This section describes the evaluation method used in all the examples described here.

(1) Melt viscosity of thermoplastic resin A (steady shear viscosity) Dynamic spectrometer R manufactured by Rheometrics
Using DSII, cone / disk rheometer (diameter 2
5 mm, cone angle 0.099 radian, gap 49 μm) in a nitrogen atmosphere.

(2) Properties of thermoplastic composite material Uniformity of shape Width measuring device (Rayscale RS15 manufactured by Keyence Corporation)
10) was used to continuously measure the width (length of the longest section of the cross section) of the thermoplastic composite material produced. Resin impregnation state A thermoplastic composite material cut into a length of about 1 cm is embedded in unsaturated polyester resin, and its cross section is precisely polished using a polishing machine (system sample polishing machine L-1000 manufactured by Japan Geoscience Co., Ltd.). Then, it was observed with a scanning electron microscope. Same as fiber dispersion. Composition (fiber content) 1) In the case of glass fiber It was obtained by heating and decomposing the resin. 2) In the case of carbon fiber / nylon It was obtained by decomposing the resin with concentrated sulfuric acid.

(3) Properties of molded product (unidirectionally laminated material) Appearance (voids, fiber arrangement) Evaluation was conducted by visual observation. Composition (fiber content) Same as (2)-. 0 ° Bending Property Using Universal Material Testing Machine Model 1185 manufactured by Instron Co., Ltd., it was performed according to ASTM D790 (three-point bending). The same equipment as for interlaminar shear strength was used and was performed according to ASTM D2344.

Example 1 Low molecular weight maleic anhydride-modified polypropylene (manufactured by Sanyo Kasei Co., Ltd., trade name Umex 1001, number average molecular weight 15,000, using a 20 mm single screw extruder at 180 ° C.)
(Shear rate of 10 ² sec ^-1, 180 ° C.) acid value 26 mg KOH / g, a softening point of 154 ° C., a melt viscosity 7.5 Pa ·
Second) crosshead die (die width 6 mm, gap 0.4
mm) (extrusion rate 5 g / min). One glass fiber tow (manufactured by Nippon Electric Glass Co., Ltd., fiber diameter 17 μm, 1150 tex, aminosilane treatment) preheated at 150 ° C. was introduced into this crosshead die and pulled out. Next, this is a freely rotating stainless steel roller with a surface coated with Teflon (diameter: 33 mm, length: 16 mm).
(cm) 12 pieces are alternately arranged in different steps (contact angle 70
°) It was introduced into hot air open (155 ° C), wound around a roller and taken out to obtain a pre-impregnated material. Further, the pre-impregnated product is guided to a crosshead die (die width 8 mm, gap 0.4 mm) attached to a 20 mm single screw extruder, and 2
Polypropylene at 30 ° C (UBE PolyPro J130G, MFI (melt flow index) manufactured by Ube Industries, Ltd.)
30) was coated around it (extrusion rate 30 g / min). Then, the tape-shaped thermoplastic composite material having a width of 7 mm and a thickness of 0.35 mm was manufactured by solidifying with a cooling roll (surface temperature 15 ° C.), winding with a take-up roll, and winding. The take-up speed was 30 m / min. The evaluation results of this composite material are shown in Table 1. Further, this tape-shaped thermoplastic composite material is heated by a drum blasting method (tape winding method) using a hot blaster (2
Winding on a drum (diameter 400 mm) (peripheral speed 3 m / min) while keeping it at 50 ° C., width 350 mm, length 1260 mm,
A unidirectional sheet having a thickness of 0.4 mm was created. This sheet was cut into a 160 mm × 160 mm square shape, and 5 plies thereof were stacked in the same direction and pressed at 170 ° C. and 1 MPa for 1 minute by press molding, and then water at 20 ° C. was introduced into the mold while being pressed. Then, it was cooled and solidified to form a unidirectional laminated plate (thickness: 1.6 mm). The evaluation results of this molded product are shown in Table 2.

[0049]

[Table 1]

[0050]

[Table 2]

Example 2 In Example 1, the thermoplastic resin A and the thermoplastic resin B were used.
Table 1 shows the results obtained by exactly the same method except that the take-up speed was changed from 30 m / min to 50 m / min from the extrusion rates of 5 g / min and 30 g / min, respectively.

Example 3 and Example 4 In Example 1, the thermoplastic resin B was changed from polypropylene to maleic anhydride modified polypropylene (UBE Polypro TX283 manufactured by Ube Industries, maleic anhydride graft ratio 0.2%, MFI 35) and 2 respectively. -Hydroxyethylmethacrylate (HEMA) modified polypropylene (UBE Polypro MH4 manufactured by Ube Industries, HEMA graft ratio 0.
Table 1 and Table 2 show the results obtained in exactly the same manner except that 5%, MFI85) was used.

Example 5 and Example 6 In Example 1, the polypropylene extrusion rate was 30 g /
Tables 1 and 2 show the results obtained in exactly the same manner except that the amounts were changed to 20 g / min and 10 g / min, respectively.

Example 7 Table 1 shows the results obtained in exactly the same manner as in Example 1 except that the cross-sectional shape of the crosshead die was changed from a slit to a circle (diameter 2 mm).

Example 8 Table 1 shows the results obtained in exactly the same manner as in Example 2, except that the cross-sectional shape of the crosshead die was changed from a slit to a circle (diameter 2 mm).

Example 9 In Example 1, the pre-impregnated material was solidified with a cooling roll (surface temperature: 15 °) and once wound on a bobbin (width 6 m).
m, thickness 0.3 mm). Then, the bobbin was set on a creel and sent out, and then guided to a crosshead gui attached to a 20 mm single screw extruder in the same manner as in Example 1 and coated with polypropylene to produce a thermoplastic composite material (width 7 mm, thickness). 0.35 mm). The take-up speed at this time is 30
m / min. Further, a molded product was prepared and evaluated in exactly the same manner as in Example 1. The results are shown in Tables 1 and 2.

Comparative Example 1 Tables 1 and 2 show the results obtained in the same manner as in Example 1 except that the roller was not used.

Comparative Example 2 Table 1 shows the results obtained in exactly the same manner as in Example 1, except that the free rotation of the roller was stopped.

Comparative Example 3 Using a blender, a dry blend of a low molecular weight maleic anhydride modified polypropylene and a polypropylene having the same blending ratio as in Example 1 was prepared. In Example 1, from this blend (shear rate melt viscosity (10 ² sec ^-1, 230 ℃) 98Pa · s) was used instead of low molecular weight polypropylene modified with maleic anhydride, 180 ° C. The temperature of the extruder 230 ° C, glass fiber preheat temperature 150 ° C to 200 ° C, hot air oven temperature 155
A pre-impregnated material was obtained in exactly the same manner except that the temperature was changed from 0 ° C to 200 ° C (the coating step was not performed). Further, a molded product was prepared in the same manner as in Example 1. The evaluation results of the composite material and the molded product are shown in Tables 1 and 2.

Comparative Example 4 In Example 1, only impregnation with a low molecular weight maleic anhydride-modified polypropylene was carried out (extrusion amount 35 g / min),
Tables 1 and 2 show the results obtained by carrying out in exactly the same manner except that the coating with polypropylene was not carried out.

Example 10 Using a 20 mm single screw extruder at 260 ° C., low molecular weight nylon 6 (number average molecular weight 3,955, melt viscosity (1
0 of ² sec ^-1 shear rate, was fed to the crosshead die was used at 260 ° C.) 15 Pa · sec) Example 7. A piece of glass fiber tow (the same as that used in Example 7) which had been preheated at 230 ° C. was introduced into this crosshead die and pulled out. Then, this was introduced into a hot air oven (230 ° C.) incorporating the impregnating roller used in Example 1, and a pre-impregnated material was obtained in the same manner. Further, this pre-impregnated material was introduced into the crosshead die used in Example 7 to obtain 26
Nylon 6 at 0 ° C (UBE nylon 1 made by Ube Industries)
013B, relative viscosity 2.6) was coated around it. Thereafter, a strand-shaped thermoplastic composite material was produced in exactly the same manner as in Example 7. The evaluation results of this composite material are shown in Table 1.

Example 11 In Example 10, the extrusion rates of low molecular weight nylon 6 and nylon 6 were 5 g / min to 10 g / min and 30 respectively.
Changed from g / min to 26 g / min and changed to glass fiber tow to replace carbon fiber (Toray, trading card T300, fiber diameter 7μ
m, 800 tex) is used, and the results obtained in exactly the same manner are shown in Table 1.

As seen in these examples, when the roller is not used (Comparative Example 1), when the free rotation of the roller is stopped (Comparative Example 2), and when the high-viscosity resin is used as the thermoplastic resin A (Comparative Example 3), when the coating with the thermoplastic resin B is not carried out (Comparative Example 4), it is not possible to provide a thermoplastic composite material having good properties or a molded article obtained from them.

[0064]

As is apparent from the above examples and comparative examples, according to the present invention, a thermoplastic composite material exhibiting a good resin impregnation state can be produced at high speed. This was not possible with the prior art. As a result, the thermoplastic composite material produced by the present invention is inexpensive and has excellent physical properties, and therefore, particularly for automobile materials, which attach great importance to cost / performance, electrical / electronic materials, building materials,
It can be put to practical use as an aircraft material.

[Brief description of drawings]

FIG. 1 is an example of a flowchart of a manufacturing apparatus related to a manufacturing method of the present invention.

[Explanation of symbols]

 1 ... Creel 2 ... Continuous reinforcing fiber 3 ... Guide roll 4 ... Preheating device 5 ... Extruder 6 ... Thermoplastic resin A 7 ... Crosshead die 14 ... Roller 15 ... Pre-impregnated material 16 ... Crosshead Die 17 ... Extruder 18 ... Thermoplastic resin B 19 ... Cooling device 20 ... Take-up device 21 ... Thermoplastic composite material 22 ... Winding device

FIG. 2 shows an example of a structure (cross section) of a crosshead die used in the present invention.

[Explanation of symbols]

 8 ... Manifold 9 ... Resin flow path 10 ... Resin / fiber confluence point 11 ... Guider chip 12 ... Guider chip gap 13 ... Die part

FIG. 3 is a diagram showing an example of a layout of rollers used in the present invention, (A) showing a case where the rollers are alternately staggered, and (B) showing a rotation axis of the rollers on the same straight line. It is a figure showing a case (however, all the rollers have the same shape).

[Explanation of symbols]

 D …… Roller diameter 1 …… Horizontal distance between rollers h …… Vertical distance between rollers θ …… Contact angle between roller and fiber

Claims (1)

[Claims] 1. An extruder having a shear viscosity at 10 ² sec ⁻¹ of 1 to 20 Pascal · sec, and a polar skeleton or a side chain having a chemical affinity with a functional group on the fiber surface. The temperature at which the thermoplastic resin A melts after the continuous reinforcing fiber is pulled out through a crosshead die in which a die part to which a thermoplastic resin having a base (hereinafter referred to as "thermoplastic resin A") is supplied is linear. In order to produce a pre-impregnated product by winding it around at least two or more freely rotating cylindrical rollers placed perpendicular to the fiber direction, and further using a crosshead die in which the die part has a linear shape. The pre-impregnated material is melted at a temperature higher than that of the thermoplastic resin A, and has a higher shear viscosity than that of the thermoplastic resin A at the same temperature and the same shear rate, and the thermoplastic resin A thermoplastic resin (hereinafter, referred to as "thermoplastic resin B") which is compatible in the molten state is prepared by coating with at least 20
A method for producing a thermoplastic composite material, characterized in that the thermoplastic composite material is collected at a speed of m / min or more.