JPH05177630A - Pellet of long-fiber reinforced thermoplastic resin and preparation of the same - Google Patents

Abstract

PURPOSE:To enable the optional adjustment of a fiber content in the preparation of pellets by mixing a two solution reactive monomer forming a thermoplastic resin, impregnating reinforcing long fibers and resin-fiber composition compatible with the monomer with the solution to form a coating layer on the surfaces, polymerizing the monomer, and by cutting the reaction product. CONSTITUTION:It is desired that the resin of a resin-fiber composition is a thermoplastic resin, and when a resin formed by two solution reaction is polyamide, the resin is composed of a polyamide composition or a polymer allot of it. The amount supplied and kind of a fibrous material can be set according to the properties required for the secondary processing. Additives including coloring agents, weathering agents, and flame retardants which improve the properties of pellets can be incorporated in the resin-fiber composition and a coating layer. For the coating layer, a composition is used as in the case of the resin-fiber composition. Reinforcing fibers and the resin-fiber composition, after being supplied to the coating head of an extruder through a nipple to form the coating layer, is led to a polymerization chamber to polymerize the monomer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention is particularly applicable to moldability, colorability,
TECHNICAL FIELD The present invention relates to a long-fiber-reinforced thermoplastic resin pellet which is versatile as a raw material for a molded article having excellent mechanical strength and a method for producing the same.

[0002]

2. Description of the Related Art Various composite materials of reinforcing fibers and thermoplastic resins have been used for electric parts, automobile parts, etc. because of their lightness, high strength and corrosion resistance. It is known that long-fiber-reinforced resin pellets used for these purposes are obtained by impregnating long-fiber reinforcing fibers with a thermoplastic resin in a molten form or in a solution form dissolved in a solvent and then cutting it into a predetermined length. However, the long-fiber-reinforced pellets obtained by this method are difficult to impregnate the long-fiber-shaped reinforcing fibers with the molten thermoplastic resin, and it is difficult to remove the solvent by impregnation with a solution. There was not enough problem.

As a solution to these problems, and particularly to the improvement of impregnation into reinforcing fibers, the present inventors have previously proposed Japanese Patent Application No. 2-1790.
As filed as No. 64, two low-viscosity reactive liquid monomers are mixed in a mixing chamber, impregnated into reinforcing fibers, and then polymerized while the outer periphery is covered with a protective coating layer, and then the reinforcing fibers are taken up. We have developed a method for cutting pellets into desired length.

According to this method, fiber-reinforced thermoplastic resin pellets can be produced easily in terms of equipment and handling, and the resin pellets obtained have a fiber content of 65 wt% when the reinforcing fibers are glass fibers. The pellets are highly filled and wet well with resin and have excellent mechanical strength.

[0005]

However, when secondary processing such as injection molding is performed using the pellets, it is difficult to form a thin-walled molded product due to the highly filled fiber, and depending on the desired shape. Fiber dispersibility and surface smoothness may be lacking, and depending on the form of use, it may not necessarily be a highly filled product, and colorants, weathering agents,
Addition of additives such as flame retardants causes color spots, making them not versatile as molding materials.

On the other hand, dry blending is one of the first possible methods for reducing the fiber content during secondary processing.
However, dry blending is a mixture of the same type of thermoplastic resin pellets for weight increase or a masterbatch with the same at the time of secondary processing, and the fiber content can be reduced by the amount of resin increase. It is difficult to disperse the particles evenly, there are many variations in the weight of each molded product, and variations such as color spots tend to occur.

On the other hand, it would be advantageous if the number of fibers could be reduced or the resin content could be increased during production, but the following problems would occur.

That is, since the monomer has an extremely low viscosity at the time of production, if the number of reinforcing fibers to be supplied is reduced, the shapeability at the time of pellet molding becomes unstable, and the fiber content fluctuates due to the fluctuation of the pellet diameter. There is a problem that it grows.

Further, the resin material forming the protective coating layer may be made of a resin compatible with the resin pellets, and the thickness of the coating layer may be increased, but the protective coating layer is originally shaped This is a step added for the purpose of improving the thickness and is formed as thin as possible. On the contrary, when the coating layer is made thick, it becomes difficult to uniformly transmit the temperature to the inside during the polymerization in the polymerization chamber, and unreacted gas is generated, which becomes a factor of inhibiting the polymerization.

Furthermore, in the case of adding an additive such as a colorant, a weatherproofing agent and a flame retardant during the production, it is necessary to select an addition range and materials that do not inhibit the polymerization reaction, and it is not always possible to obtain desired properties. Can not.

The present invention has been made to solve the above problems, and an object thereof is to make it possible to arbitrarily adjust the fiber content during the production of pellets, and to optionally adjust the color tone and other physical properties as required. Provided are long fiber reinforced thermoplastic resin pellets and a method for producing the same.

[0012]

In order to achieve the above object, the long-fiber-reinforced thermoplastic resin pellets of the present invention are mixed with a reinforcing fiber and the thermoplastic resin in a thermoplastic resin molded by a two-component reaction. It is characterized in that a soluble thermoplastic resin fibrous material is integrated in an impregnated state.

When the thermoplastic resin is a polyamide resin, the thermoplastic resin fibrous material preferably has a composition of a polyamide resin composition or a polymer alloy resin composition with the polyamide resin composition. More specifically, not only polyamide fibrous compositions such as nylon 6 but also polyamide /
Polypropylene, Polyamide / PPO, Polyamide / A
As long as it is a thermoplastic resin fibrous composition having compatibility such as an alloy resin such as BS, its kind is not particularly limited, and its supply amount and kind can be set according to the physical properties required at the time of secondary processing. Further, additives such as a colorant, a weatherproofing agent and a flame retardant, which determine the properties of the resin pellets, can be added to the thermoplastic resin fibrous material.

Specific examples of the colorant include a sparingly soluble azo dye, a red colorant, cadmium yellow, cream yellow and titanium white. Further, specific examples of the flame retardant include inorganic ammonium oxide, zircon oxide, organic phosphoric acid ester, trichlorodiphosphate, and the like. Further, a specific example of the weather resistance agent is a hindered amine light stabilizer.

Further, a coating layer made of a thermoplastic resin compatible with the thermoplastic resin may be integrally formed on the outer periphery of the thermoplastic resin. This coating layer is a resin composition similar to the thermoplastic resin fibrous material. In this case, additives such as a colorant, a weatherproofing agent and a flame retardant, which determine the properties of the resin pellets, can be added to the coating layer in the same manner as described above.

The reinforcing fibers used in the present invention include inorganic fibers such as glass fibers and carbon fibers, and organic fibers such as aromatic polyamide, vinylon and polyester.

Further, in the production method of the present invention, two liquids of low-viscosity reactive liquid monomer are supplied to the impregnation chamber while being mixed at a predetermined ratio, and are continuously supplied in the impregnation chamber. A reinforcing fiber and a resin fibrous material having compatibility with the monomer are impregnated in the mixed solution, and then the impregnated reinforcing fiber and the resin fibrous material are led to a coating head portion of a melt extruder through a nipple to perform the impregnation. After forming a protective coating layer by melt-extruding a thermoplastic resin on the outer periphery of the reinforcing fiber and the fibrous material, it is introduced into a heated polymerization chamber to polymerize the monomers inside the protective coating layer, and then predetermined. It is characterized by cutting to the length of.

In this production method, each reactive liquid monomer is preferably a combination of a liquid lactam added with an anionic polymerization catalyst and a liquid lactam added with an activator, in the polymerization chamber. It is shaped into a fiber-reinforced polyamide resin in which the reinforcing fiber and the fibrous material are integrated in an impregnated state by anion polymerization.

Specific examples of lactams include γ-butyrolactam, δ-valerolactam, ε-caprolactam,
Examples include ω-enanthlactam, ω-capryllactam, and ω-undecanolactam. These lactams may be used alone or in combination of two or more.

As the anionic polymerization catalyst, all compounds used in the known alkaline polymerization method of lactams can be used. Specific examples thereof include alkali metals, alkaline earth metals, their hydrides, oxides,
Examples thereof include hydroxides, carbonates, alkyl compounds or alkoxides, Grignard compounds, sodium naphthalene, and reaction products of the above metal compounds with lactams such as sodium lactam, potassium lactam, and lactam magnesium bromide. These anionic polymerization catalysts are added to and mixed with 0.1 to 3 mol%, preferably 0.3 to 2.5 mol% of lactams, which are heated to a liquid monomeric lactam (hereinafter A mixed liquid of an anionic polymerization catalyst and lactams is referred to as liquid A.) As the activator, all compounds used in the known alkali polymerization method for lactams can be used.
Specific examples thereof include N-acyl lactam, organic isocyanate, acid chloride, acid anhydride, ester, urea derivative,
Carbimide and ketene can be mentioned, but the type and amount thereof are determined in consideration of the reaction initiation temperature and the pot life,
This is also added to liquid lactams (hereinafter, a mixture of the activator and lactams is referred to as liquid B).

When the thermoplastic resin used for extrusion to form the protective coating layer is a polyamide resin,
Considering the temperature when the internal reaction liquid is polymerized after the fact, it has a softening point of at least 120 ° C. or higher,
It is used by selecting from those having resistance to the reaction liquid, capable of melt extrusion, and having gas barrier properties, and suitable ones are preferable after polymerization of polypropylene resin, polyester resin, fluorine resin, etc. Listed as peelable. Further, there is a polyamide resin that can be used integrally with the coating layer.

Further, in the production method of the present invention, between the polymerization step and the cutting step, the molded body taken out is guided to the coating head portion of the melt extruder, and the outer periphery of the molded body has a heat compatible with it. The plastic resin can be melt-extruded to integrally form a coating layer having a desired thickness on the outer periphery of the molded body. In this case, the two-color extrusion molding may be carried out subsequent to the polymerization reaction, or the product in the extracted state after completion of the polymerization reaction may be stocked and, if necessary, two-color extrusion molding may be carried out by an extruder. good.

In addition to the above monomers constituting the polyamide resin, it is also possible to prepare the fiber-reinforced thermoplastic resin pellets having the above-mentioned constitution by using the other two liquid low-viscosity reactive monomers. ABS made by combining liquid acrylonitrile-butadiene copolymer and styrene monomer
Examples thereof include resins, polystyrene resins made of a combination of styrene syrup and styrene monomer, and polymethylmethacrylate resins made of a combination of methyl methacrylate syrup and methyl methacrylate monomer.

The fibrous material or coating layer having compatibility with the two-liquid reactive monomer is polystyrene, AB
S, AES, AS and other styrene resins, ABS / P
Alloy resins such as C, ABS / PBT, ABS / PA, homopolymers composed of methacrylic acid such as methyl methacrylate, ethyl methacrylate and butyl methacrylate,
And copolymers such as MBS. Although the reaction conditions and the like at the time of manufacturing these are different from those of the above polyamide resin, they can be manufactured by the same method as the above manufacturing method.

[0025]

The long-fiber-reinforced thermoplastic resin pellets obtained by the present invention, since the compatible fibrous substances contained in the pellets are melted together during the secondary processing such as injection molding to form a resin component, The occupancy ratio of the reinforcing fibers can be reduced according to the blending ratio of the fibrous material. Addition of additives such as colorants, weatherproofing agents, flame retardants to the fibrous material does not affect the polymerization reaction of the monomer, so that it can be colored or modified according to the requirements of the secondary processed product.

In addition to the above, when a coating layer made of a compatible thermoplastic resin is extrusion-molded on the outer periphery of the pellet to be integrated, the occupation ratio of the reinforcing fibers can be further reduced as described above. At the same time, since it is integrated after the completion of the polymerization, it is possible to use the one which inhibits the polymerization by the additive.

Further, in the production method of the present invention, the long fiber described above is simply changed by changing the material, changing the conditions or adding a new process without modifying the main part of the production method and the apparatus used therefor. Reinforced thermoplastic resin pellets can be manufactured.

[0028]

Next, preferred embodiments of the present invention will be described. However, the present invention is not limited to the following examples.

Example 1. 1 and 2 show the whole and part of the manufacturing process according to the present invention. In the figure, a tank 1 containing solution A, which was heated to 80 ° C. and was mixed with ε-caprolactam as a monomer by adding 1 mol% of metallic Na in the form of strips as an anionic polymerization catalyst, was mixed with 80 ° C. Heated to 1mo as an activator
A tank 2 containing liquid B containing 1% phenylisocyanate was prepared.

A mixing section 3 was provided below the tanks 1 and 2, and the mixing section 3 mixed the solutions A and B at a ratio of 1: 1 to prepare a reaction solution. The reaction liquid prepared is continuously supplied to the impregnation chamber 4 connected to the lower part of the mixing section, and the glass fiber 5a and the nylon 6 as the reinforcing fibers which have been dried are supplied into the impregnation chamber 4.
The fiber 5b was introduced into a combined state, and the mixed solution of the glass fiber 5a and the nylon 6 fiber 5b was impregnated with the reaction solution.

The circumference of the impregnation chamber 4 is maintained at 80 ° C. and a nitrogen gas atmosphere is provided, a fiber guide hole 6 having an inner diameter of 2 mm is provided at the inlet of the impregnation chamber 4, and the solution impregnating portion 7 has a length of 500 mm and an inner diameter of The conical shape was narrowed from 10 to 3 mm, and the one having a curved tube structure as shown in FIG. 2 was used so that the reaction solution did not flow back and remained.

The outlet side of the impregnating portion 7 has a guide portion 9 having an inner diameter of 3 mm and is heated to 80 by a hot water connected to a pipe 10.
It is connected to the nipple 11 which is kept at ℃.

The viscosity of the reaction solution when impregnating the glass fiber 5a and the nylon fiber 5b was 10.5 centipoise. An annular die 13 having an outer diameter of 6 mm and an inner diameter of 4 mm provided on the die head 30 of the melt extruder is provided around the outer periphery of the mixed fiber 12 impregnated with the reaction liquid introduced to the nipple 11.
A molten nylon 6 resin was extruded from the above to form a protective coating layer 14, and extrusion coating was performed at a speed of 3 m / min in a drawn state.

At this time, the inside 15 of the coating layer 14 is filled with the mixed fiber 12 and the protective coating layer 14 by introducing nitrogen gas from a pipe (not shown) into a nitrogen gas atmosphere and connecting the pipe 16 to a pressure reducing device. Improved adhesion.

The resin coating obtained in the above steps is immediately introduced into the cooling water tank 17 to cool the resin coating layer 14 on the surface, and then the polymerization tank 18 having a length of 30 m and controlled at 170 to 200 ° C. The reaction solution is continuously polymerized in the cooling water tank 19
After water cooling in the inside, it was taken up by a take-up machine 20, and then was cut into about 10 mm by a cutter 21 and pelletized. The fiber content of this long fiber reinforced thermoplastic resin pellet is 30 wt%
3A, the glass fiber 5a and the nylon 6 fiber 5b are bound to each other by the polyamide resin generated in a state of being randomly bundled inside the protective coating layer 14 as shown in FIG. The condition is observed.

After the pellets were dried at 80 ° C. for 12 hours, they were fed to an injection molding machine having a screw diameter of 16 mm and an L / D of 28, and a bending test piece of 13.5 × 120 mm and a thickness of 3 mm and a width of 13 mm and a thickness of 13 mm. A tensile test piece having a dumbbell shape of 165 mm of 2.4 mm was formed.

The molding conditions for the physical property test piece are as follows: injection pressure 1
200 kg / cm ² , mold temperature 80 ° C., screw rotation speed 200 rpm, back pressure 40 kg / cm ² , cooling time 30
Second, injection time is 5 seconds.

Further, this pellet, a conventional pellet having a fiber content of 65 wt% and a fiber content of fiber content of 6
Japan Seisakusho Co., Ltd. with a screw diameter of 38 mm in order to compare the weight variation of molded products, the dispersibility of fibers, and the surface smoothness when dry blending 5 wt% pellets.
Injection molding machine N100BII two supply 100 × 10
A plate-shaped test piece having a thickness of 0 mm and a thickness of 3.5 mm was formed. The molding conditions for this plate-shaped test piece were as follows: injection pressure 1000 Kg / cm
² , mold temperature 82 ° C., screw rotation speed 50 rpm, back pressure 10 to 20 kg / cm ² , cooling time 23 seconds, injection time 7 seconds.

As the physical properties of this sample and a conventional injection sample having a fiber content of 65 wt% for comparison, the weight variation and the fiber dispersibility were measured, and the surface smoothness was observed.

The weight variation was obtained by measuring the weight of a plate-shaped test piece for 20 shots, and defining the variation three times as much as the weight variation (%).

The fiber dispersibility was measured by dividing the obtained injection-molded product into three equal parts in length and width, cutting out into nine pieces in total, and measuring the glass fiber content, which was set to three times the coefficient of variation.

Further, the surface smoothness shows the result of observing the surface irregularities, and is expressed by the expressions ◯, Δ, and × according to the smoothness. The results are collectively shown in Table 1 below.

Example 2. The content of the nylon 6 fiber 5b in Example 1 was reduced, the glass fiber 5a was directly under the content thereof, and the thermoplastic resin coating obtained under the same molding conditions as in Example 1 was cooled and cured and further extruded. Nylon 66 resin melt-discharged from a cylindrical die of a molding machine was extrusion-coated at a rate of 3 m / min, cooled in a cooling water tank, taken up by a take-up machine, cut into about 10 mm, and pelletized. The fiber content is 30 wt%, and as shown schematically in FIG. 3B, the outer periphery of the protective coating layer 14 is further covered with a coating resin layer 50 made of nylon 66, and inside the coating layer 14. Glass fiber 5a, nylon 6 fiber 5b
It is observed that the polyamide resins produced in the state of being randomly bundled are bound to each other.

After the above pellets were dried for 12 hours, the same test pieces as in Example 1 were prepared, the weight variation and the fiber dispersibility were measured, and the surface smoothness was observed. The results are collectively shown in Table 1 below.

Comparative Example 1. Nylon 6 resin was dry blended to a conventional pellet having a fiber content of 65 wt% so as to have a fiber content of 30 wt%, and after molding in the same manner as in Example 1, the weight variation and the fiber dispersibility were measured to improve the surface smoothness. I observed. The results are collectively shown in Table 1 below.

[0046] As is clear from the results in Table 1, it is suggested that both Examples 1 and 2 have less weight variation and better fiber dispersibility than Comparative Example 1. It was also confirmed that the smoothness of the surface of the molded product was better than that of the comparative example and the conventional example.

Example 3. 2% of a red colorant was added to the thermoplastic fiber of Example 1, pelletized in the same manner as in Example 1 except for the above, and then a test piece was molded under the same conditions to evaluate the colorability. The results are collectively shown in Table 2 below.

Example 4. 2% of a red colorant was added to the nylon 66 resin in Example 2, pelletization was performed in the same manner as in Example 1 except for the above, and then a test piece was molded under the same conditions to evaluate the coloring property. The method for measuring the colored spots was performed by visual confirmation, and the description was round, triangular, or flared depending on the condition.
The results are collectively shown in Table 2.

Comparative Example 2. The nylon 6 resin of Comparative Example 1 containing 2% of a red colorant was used to evaluate the colorability of a test piece molded by dry blending. The results are collectively shown in Table 2 below.

Comparative Example 3. The colorability was evaluated under the same conditions as in Comparative Example 2 except that the amount of the red colorant in Comparative Example 2 was increased to 3%. The results are shown in Table 2 below.

[0051]

As is clear from the results shown in Table 2, Example 3,
No. 4 has a better colorability than Comparative Example 2.3, suggesting that the colorant is uniformly dispersed when melted.

[0053]

The long-fiber-reinforced thermoplastic resin pellets of the present invention can be used as a resin component by melting together compatible fibrous substances contained in the pellets during secondary processing such as injection molding. The occupancy ratio of the reinforcing fibers can be lowered according to the blending ratio of the particulate matter, and there is an advantage that the moldability is good and the surface smoothness is obtained. In addition, even if an additive such as a colorant, a weatherproofing agent, and a flame retardant is added to the fibrous material, it does not affect the polymerization reaction of the monomer, so that it can be colored or modified according to the requirements of the secondary processed product. Highly versatile.

When a coating layer made of a compatible thermoplastic resin is integrated on the outer periphery of the pellet, the occupancy ratio of the reinforcing fibers can be further reduced in the same manner as described above, and the required performance of the secondary processed product can be improved. Accordingly, the fiber content can be freely adjusted, and since the fibers are integrated after the completion of the polymerization, it is possible to use a fiber which inhibits the polymerization by an additive, which further enhances the versatility.

Further, in the production method of the present invention, the long fiber described above is simply changed by changing the material, changing the conditions, or adding a new step without modifying the main parts of the production method and the apparatus used therefor. Reinforced thermoplastic resin pellets can be manufactured.

[Brief description of drawings]

FIG. 1 is an overall explanatory view showing steps of a manufacturing method according to the present invention.

FIG. 2 is a detailed view of an essential part of FIG.

3 (a) is a schematic cross-sectional view of a long fiber reinforced thermoplastic resin pellet obtained in Example 1. FIG. (B) is a schematic cross-sectional view of the long fiber reinforced thermoplastic resin pellet obtained in Example 2.

[Explanation of symbols]

3 Mixing chamber 4 Impregnation chamber 5a Reinforcing fiber (glass fiber) 5b Compatible thermoplastic resin fibrous material (nylon 6
Resin) 14 Protective coating layer 18 Polymerization tank 20 Drawer 21 Cutter 30 Die head 50 Coating layer (nylon 66)

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display area C08L 77/02 LQS 9286-4J // B29K 77:00 105: 06

Claims (9)

[Claims] 1. A reinforcing resin and a thermoplastic resin fibrous material compatible with the thermoplastic resin are integrated in a thermoplastic resin molded by a two-liquid reaction in an impregnated state. Long fiber reinforced thermoplastic resin pellets. 2. The thermoplastic resin according to claim 1, wherein the thermoplastic resin is a polyamide resin, and the thermoplastic resin fibrous material comprises a polyamide resin composition or a polymer alloy resin composition with the polyamide resin composition. Fiber reinforced thermoplastic resin pellets. 3. The thermoplastic resin fibrous material is mixed with additives such as a colorant, a weatherproofing agent and a flame retardant, which determine the properties of the resin pellets. Long fiber reinforced thermoplastic resin pellets. 4. The long-fiber-reinforced thermoplastic resin according to claim 1, wherein a coating layer made of a thermoplastic resin compatible with the thermoplastic resin is integrally formed on the outer periphery of the thermoplastic resin. pellet. 5. The thermoplastic resin according to claim 4, wherein the thermoplastic resin is a polyamide resin, and the thermoplastic resin forming the coating layer is a polyamide resin composition or a polymer alloy resin composition with the polyamide resin composition. The long-fiber-reinforced thermoplastic resin pellets described. 6. The long fiber reinforced according to claim 4, wherein the coating layer contains additives such as a colorant, a weatherproofing agent and a flame retardant which determine the properties of the resin pellets. Thermoplastic resin pellets. 7. A low-viscosity reactive liquid monomer of 2 parts is supplied to an impregnation chamber while being mixed at a predetermined ratio, and continuous filaments of reinforcing fibers and the above-mentioned monomers are continuously supplied in the impregnation chamber. A resin fibrous material having compatibility is impregnated in the mixed liquid, and subsequently, the impregnated reinforcing fiber and the resin fibrous material are guided to a coating head portion of a melt extruder through a nipple to obtain the impregnated reinforcing fiber and the fibrous material. After forming a protective coating layer by melt-extruding a thermoplastic resin on the outer periphery of, the polymer is introduced into a heated polymerization chamber to polymerize the monomers inside the protective coating layer, and then cut into a predetermined length A method for producing long-fiber-reinforced thermoplastic resin pellets, comprising: 8. Each of the reactive liquid monomers is a combination of a liquid lactam added with an anionic polymerization catalyst and a liquid lactam added with an activator, and anionic polymerization is performed in the polymerization chamber. The method for producing long-fiber-reinforced thermoplastic resin pellets according to claim 7, wherein the reinforcing fiber and the fibrous material are molded into a fiber-reinforced polyamide resin integrated in an impregnated state. 9. Between the polymerization step and the cutting step, the molded body taken out is guided to the coating head portion of a melt extruder, and a thermoplastic resin compatible with the molded body is melt-extruded and molded on the outer periphery of the molded body. The method for producing long-fiber-reinforced thermoplastic resin pellets according to claim 7 or 8, wherein a coating layer having a desired thickness is integrally formed on the outer circumference of the body.