JPH05220852A - Preparation of long filament reinforced polyamide resin composition - Google Patents

Abstract

PURPOSE:To prepare a long fiber-reinforced polyamide resin compsn. by a method wherein amt. of the remaining monomer is small and the yield can be improved and a combination of a catalyst and an activating agent with which an obtd. polymer does not become to a high mol. wt. level where it is hardly molded is used. CONSTITUTION:A liq. lactam incorporated with sodium hydride as an anionic polymn. catalyst and a liq. lactam wherein a bifunctional org. isocyanate and a monofunctional org. isocyanate are mixed as an activating agent are fed into an impregnation room 4 while they are mixed by a specified ratio and a long filament-like reinforcing fiber 5 being continuously fed is impregnated with the mixed soln. in the impregnation room 4 and then, this is guided into a covering head of a melt-extrunder through a nipple 11 and the outer periphery of this impregnated reinforced fiber is covered with a molten thermoplastic resin with a softening temp. of at least 120 deg.C to form a seamless covering layer 14 and then, this is introduced in a heated polymer tank, wherein anion polymn. of the lactam existing inside of the covering layer 14 is performed and the product is cut into a specified length.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a long-fiber-reinforced polyamide resin composition, and more particularly to a method for producing a polyamide resin after reaction with a small amount of residual monomers and a high yield.

[0002]

2. Description of the Related Art Various fiber-reinforced thermoplastic resin pellets made of a thermoplastic resin and reinforcing fibers and having excellent mechanical strength have been studied so far. The present applicant also studied a method for obtaining a fiber-reinforced polyamide resin composition easily in terms of equipment and handling, and has already filed as Japanese Patent Application No. 2-179064.

In the manufacturing method according to this application, long fiber-shaped reinforcing fibers are impregnated while continuously mixing lactams to which an anionic polymerization catalyst and an activator are added respectively, and immediately the outer periphery thereof is melted with a thermoplastic resin. After being coated with the above, it is supplied to a heating tank, an internal lactam is anionically polymerized in the presence of the catalyst and the activator, and then cut into a predetermined length to form a pellet.

The anionic polymerization catalyst used in this production method is selected from the alkali metals and alkaline earth metals used in the generally known alkali polymerization method for lactams. Further, the activator is selected from N-acyl lactam, which is a compound used in the known alkali polymerization method of lactams, organic isocyanate, acid chloride, acid anhydride, ester, urea derivative, carboimide and ketene. ..

According to this method, the fiber-reinforced thermoplastic resin pellets can be easily manufactured in terms of equipment and handling, and the resin pellets obtained are pellets having good wetting of the reinforcing fibers with the resin and excellent mechanical strength. ..

In this method, as the coating resin,
When a resin compatible with the obtained polyamide resin composition is selected, the resin is compatible with the resin composition formed inside the coating layer, so that the step of peeling off the coating layer after molding becomes unnecessary and the secondary processing is performed. Sometimes there is the advantage that the coating can be used as is.

However, depending on the type of these compatible coating resins, the anionic polymerization of lactams inside the coating layer is inhibited by the decomposition gas generated during coating, and unreacted lactam or low molecular weight components (hereinafter referred to as residual monomer and There are many drawbacks. Since a composition containing a large amount of this type of residual monomer causes depolymerization of the polyamide during secondary processing, it is necessary to extract and separate the residual monomer immediately after production, and the yield decreases if this component is large.

As a thermoplastic coating resin which does not inhibit the polymerization, there is, for example, a fluorine resin, but this fluorine resin has poor compatibility with a polyamide resin, and therefore the coating is peeled off during secondary processing. The need arises and productivity falls. Therefore, as a result of studying a combination of a catalyst and an activator which does not inhibit polymerization, the applicant has found that a combination of sodium hydride as an anionic polymerization catalyst and a bifunctional isocyanate as an activator has 10% or less residual monomer. It was confirmed that the yield was improved.

[0009]

However, when a bifunctional isocyanate is used as an activator, the molecular weight of the polymerized lactam becomes very high. When the molecular weight becomes high, the viscosity at the time of melting rises, the subsequent molding at the time of secondary processing becomes difficult, and filling failure due to insufficient fluidity and breakage of the reinforcing fiber cause a decrease in mechanical strength.

The present invention is intended to solve the above problems, and its object is to use a resin compatible with a polyamide resin as a coating resin by devising a combination of an anionic polymerization catalyst and an activator. In addition, various studies have been conducted on various combinations of catalysts and activators that have a small amount of residual monomers, can improve the yield, and do not increase the molecular weight to such an extent that the polymer is difficult to mold, and have completed the present invention.

[0011]

In order to achieve the above object, the present invention provides a liquid lactam containing sodium hydride as an anionic polymerization catalyst, a bifunctional organic isocyanate and a monofunctional as an activator. Liquid lactams to which is mixed and added the organic isocyanate of are supplied to the impregnation chamber while being mixed at a predetermined ratio, and the continuous liquid is continuously impregnated in the impregnation chamber to impregnate the mixed liquid. Then, this was guided to the coating head of the melt extruder through a nipple, and the outer periphery of the impregnated reinforcing fiber was melt-coated with a thermoplastic resin having a softening point of 120 ° C. or more to form a seamless coating layer. After that, it is introduced into a heated polymerization chamber to anionically polymerize the lactams inside the coating layer, and then cut into a predetermined length.

In the above production method, specific examples of the lactams used in the polymerization reaction include γ-butyrolactam, Σ-valerolactam, ε-caprolactam and ω.
-Enanthlactam, ω-capryllactam, ω-undecanolactam. These lactams may be used alone or in combination of two or more.

As the anionic polymerization catalyst, sodium hydride is selected from the compounds used in the known alkaline polymerization method of lactams, and the amount is 0.1 to lactams.
3 mol%, preferably 0.3 to 2.5 mol% is heated and added to the liquid monomeric lactams and mixed (hereinafter referred to as liquid A).

Specific examples of the bifunctional organic isocyanate used as the activator include hexamethylene diisocyanate, 4,4-diphenylmethane diisocyanate, 2,
4-toluene diisocyanate or the like is selected. Examples of monofunctional isocyanates used in combination with this bifunctional isocyanate include phenyl isocyanate, cyclohexyl isocyanate, and naphthyl isocyanate.

At this time, in determining the mixing ratio of the bifunctional / monofunctional isocyanate, if the mixing ratio of the monofunctional is low, the molecular weight of the polymer to be obtained becomes high and the secondary molding becomes difficult. On the other hand, when the mixing ratio of the bifunctional is low, there is a problem that the amount of residual monomer increases due to the influence of moisture from the melt-coated resin and the influence of decomposition gas and the yield decreases.
Therefore, it is necessary to determine the compounding ratio that satisfies these contradictory conditions. According to the experiment, the mixing ratio of monofunctional / monofunctional + bifunctional isocyanate: 0.1 to 0.9,
More preferably, 0.3 to 0.7 is a suitable blending ratio.
Further, the total amount of this organic isocyanate is 0.2 to 3
Mol%, preferably 0.5 to 2.0 mol% is heated and added to the liquid monomeric lactams and mixed (hereinafter referred to as liquid B).

Inorganic fibers such as glass fibers and carbon fibers, and organic fibers such as polyester can be used as the reinforcing fibers.

The thermoplastic resin used in the coating layer is compatible with the polymerization product, has a softening point of at least 120 ° C. or higher in consideration of the temperature during anionic polymerization, and is a resin having a high resistance to the reaction solution. good. Specifically, polyamide resin, polyamide / polypropylene, polyamide / P
Alloy resins such as PO and polyamide / ABS can be covered.

[0018]

By using sodium hydride as the anionic polymerization catalyst in the liquid A, the catalytic activity can be stabilized. Further, by using a bifunctional organic isocyanate as an activator in the liquid B, the anionic polymerization rate is increased, and the polymerization reaction is stably performed without being affected by the polymerization inhibitor such as water and decomposition gas from the melt-coated resin. While being completed and reducing the residual monomer, the degree of polymerization of the polymer can be controlled low due to the presence of the monofunctional organic isocyanate.

[0019]

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, it is heated to 80 ° C., tank 1 containing solution A mixed with ε-caprolactam as a monomer and 1 mol% sodium hydride added as an anionic polymerization catalyst, and also heated to 80 ° C. As an activator.
5 mol% hexamethylene diisocyanate (henceforth HD
A tank 2 containing a solution B to which 0.5 mol% of phenyl isocyanate (hereinafter abbreviated as PhNCO) was added was prepared.

A mixing section 3 was provided below the tanks 1 and 2, and the reaction solution was prepared by mixing the solutions A and B at a ratio of 1: 1. The reaction liquid prepared in the impregnation chamber 4 connected to the lower portion of the mixing section 3 is continuously supplied, and the glass fiber 5 made of glass roving, which is the reinforcing fiber that has been dried, is guided into the impregnation chamber 4. The glass fiber 5 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 a 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 a curved tube structure was used as shown in FIG. 2 so as to prevent backflow and retention of the reaction solution.

An 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 hot water connected to a pipe 10.
It is connected to the nipple 11 which is kept at ℃.

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

The resin coating obtained in the above steps is immediately introduced into a cooling water tank 17 to cool the surface coating layer 14, and then in a polymerization tank 18 having a length of 30 m and controlled at 170 to 200 ° C. The reaction liquid is continuously polymerized with, cooled with water in the cooling water tank 19, and then taken up by the take-up machine 20, and then the cutter 21.
It was cut into about 10 mm and pelletized.

This composition was subjected to Soxhlet extraction with methanol as a solvent to remove residual monomers. The amount of residual monomer was calculated from the weight of the polymerized polyamide before and after the extraction with respect to the initial amount of lactam raw material. Further, the number average molecular weight was measured by a viscosity method. The results are collectively shown in Table 1.

Next, the composition after removal of the residual monomer was fed to an injection molding machine having a screw diameter of 38 mm and the outer shape was 12.4.
Bending test piece of 126 mm x 6.4 mm thick and 12.7 x
A dumbbell-shaped tensile test piece having a thickness of 181 mm and a thickness of 3.2 mm was molded, and bending strength, bending elastic modulus, tensile strength and Izod impact strength were measured. The results are shown in Table 2. In addition,
The molding conditions of the test piece are as follows: injection pressure 1000 kg / cm ² , mold temperature 80 ° C., screw rotation speed 30 rpm, cooling time 45 seconds, injection time 5 seconds.

Example 2. HDI 0.2 as activator
A resin composition was obtained under the same production conditions as in Example 1 except that 5 mol% and PhNCO were 0.5 mol%, and the residual monomer amount and the average molecular weight were measured. The results are collectively shown in Table 1 below.

Example 3. HDI 0.5 as activator
A resin composition was obtained under the same manufacturing conditions as in Example 1 except that mol% and PhNCO were changed to 0.25 mol%, and the residual monomer amount and the average molecular weight were measured. The results are collectively shown in Table 1 below.

Comparative Example 1. HDI only 1 as activator
A resin composition was obtained under the same production conditions as in Example 1 except that the amount was mol%, and the residual monomer amount, average molecular weight and mechanical strength were measured. The results are collectively shown in Tables 1 and 2 below.

Comparative Example 2. A resin composition was obtained under the same production conditions as in Example 1 except that only PhNCO was used as the activator at 1 mol%, and the residual monomer amount and average molecular weight were measured. The results are collectively shown in Table 1 below.

[0032]

[Table 1] From Table 1, it is shown that Comparative Example 1 has less residual monomer, but the average molecular weight is almost twice that of Examples 1, 2, and 3. Further, it can be confirmed that the molecular weight of Comparative Example 2 is small, but the amount of residual monomer reaches about 2.5 to 3 times that of Examples 1, 2, and 3.

[0033]

[Table 2] As is clear from Table 2 above, in Example 1, the residual fiber length after molding is long, and the physical properties in the molded state are higher than in Comparative Example 1 except for the flexural modulus. This is because the degree of polymerization is low, so that the fluidity at the time of molding is good and the reinforcing fibers are not damaged. The relationship between the injection pressure and the filling amount is shown in FIG. According to this, it is shown that the composition of Example 1 having a smaller molecular weight has a higher filling rate under the same injection pressure and better fluidity than Comparative Example 1.

[0034]

As described above in detail with reference to the examples, according to the production method of the present invention, the use of a bifunctional organic isocyanate as the activator in the solution B increases the anionic polymerization rate, resulting in melt coating. While the polymerization reaction is completed stably without being affected by the polymerization inhibitor such as water or decomposition gas from the resin, and the residual monomer is reduced,
The presence of the monofunctional organic isocyanate makes it possible to control the degree of polymerization of the polymer to a low level, so that the obtained long-fiber-reinforced polyamide resin composition can be produced with a higher yield than before, but has good fluidity during secondary molding. Therefore, there is an advantage that productivity is improved and a molded product having high strength can be obtained without defective filling or breakage of reinforcing fiber.

[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.

FIG. 3 is a graph comparing the relationship between the injection pressure and the filling amount when the resin compositions obtained in Example 1 and Comparative Example 1 are injection molded.

[Explanation of symbols]

 3 Mixing Chamber 4 Impregnation Chamber 5 Reinforcing Fiber (Glass Fiber) 11 Nipple 14 Covering Layer 18 Polymerization Tank 20 Pulling Machine 21 Cutter 30 Die Head

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[Procedure amendment]

[Submission date] August 26, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Full text

[Correction method] Change

[Correction content]

[Document name] Statement

Title: Method for producing long fiber reinforced polyamide resin composition

[Claims]

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a long-fiber-reinforced polyamide resin composition, and more particularly to a method for producing a polyamide resin after reaction with a small amount of residual monomers and a high yield.

[0002]

2. Description of the Related Art Various fiber-reinforced thermoplastic resin pellets made of a thermoplastic resin and reinforcing fibers and having excellent mechanical strength have been studied so far. The present applicant also studied a method for obtaining a fiber-reinforced polyamide resin composition easily in terms of equipment and handling, and has already filed as Japanese Patent Application No. 2-179064.

In the manufacturing method according to this application, long fiber-shaped reinforcing fibers are impregnated while continuously mixing lactams to which an anionic polymerization catalyst and an activator are added respectively, and immediately the outer periphery thereof is melted with a thermoplastic resin. After being coated with the above, it is supplied to a heating tank, an internal lactam is anionically polymerized in the presence of the catalyst and the activator, and then cut into a predetermined length to form a pellet.

The anionic polymerization catalyst used in this production method is selected from the alkali metals and alkaline earth metals used in the generally known alkali polymerization method for lactams. Further, the activator is selected from N-acyl lactam, which is a compound used in the known alkali polymerization method of lactams, organic isocyanate, acid chloride, acid anhydride, ester, urea derivative, carboimide and ketene. ..

According to this method, the fiber-reinforced thermoplastic resin pellets can be easily manufactured in terms of equipment and handling, and the resin pellets obtained are pellets having good wetting of the reinforcing fibers with the resin and excellent mechanical strength. ..

In this method, as the coating resin,
When a resin compatible with the obtained polyamide resin composition is selected, the resin is compatible with the resin composition formed inside the coating layer, so that the step of peeling off the coating layer after molding becomes unnecessary and the secondary processing is performed. Sometimes there is the advantage that the coating can be used as is.

However, depending on the type of these compatible coating resins, the anionic polymerization of lactams inside the coating layer is inhibited by the decomposition gas generated during coating, and unreacted lactam or low molecular weight components (hereinafter referred to as residual monomer and There are many drawbacks. Since a composition containing a large amount of this type of residual monomer causes depolymerization of the polyamide during secondary processing, it is necessary to extract and separate the residual monomer immediately after production, and the yield decreases if this component is large.

As a thermoplastic coating resin which does not inhibit the polymerization, there is, for example, a fluorine resin, but this fluorine resin has poor compatibility with a polyamide resin, and therefore the coating is peeled off during secondary processing. The need arises and productivity falls. Therefore, as a result of studying a combination of a catalyst and an activator which does not inhibit polymerization, the applicant has found that a combination of sodium hydride as an anionic polymerization catalyst and a bifunctional isocyanate as an activator has 10% or less residual monomer. It was confirmed that the yield was improved.

[0009]

However, when a bifunctional isocyanate is used as an activator, the molecular weight of the polymerized lactam becomes very high. When the molecular weight becomes high, the viscosity at the time of melting rises, the subsequent molding at the time of secondary processing becomes difficult, and filling failure due to insufficient fluidity and breakage of the reinforcing fiber cause a decrease in mechanical strength.

The present invention is intended to solve the above problems, and its object is to use a resin compatible with a polyamide resin as a coating resin by devising a combination of an anionic polymerization catalyst and an activator. In addition, various studies have been conducted on various combinations of catalysts and activators that have a small amount of residual monomers, can improve the yield, and do not increase the molecular weight to such an extent that the polymer is difficult to mold, and have completed the present invention.

[0011]

In order to achieve the above object, the present invention provides a liquid lactam containing sodium hydride as an anionic polymerization catalyst, a bifunctional organic isocyanate and a monofunctional as an activator. Liquid lactams to which is mixed and added the organic isocyanate of are supplied to the impregnation chamber while being mixed at a predetermined ratio, and the continuous liquid is continuously impregnated in the impregnation chamber to impregnate the mixed liquid. Then, this was guided to the coating head of the melt extruder through a nipple, and the outer periphery of the impregnated reinforcing fiber was melt-coated with a thermoplastic resin having a softening point of 120 ° C. or more to form a seamless coating layer. After that, it is introduced into a heated polymerization chamber to anionically polymerize the lactams inside the coating layer, and then cut into a predetermined length.

In the above production method, specific examples of the lactams used in the polymerization reaction include γ-butyrolactam, Σ-valerolactam, ε-caprolactam and ω.
-Enanthlactam, ω-capryllactam, ω-undecanolactam. These lactams may be used alone or in combination of two or more.

As the anionic polymerization catalyst, sodium hydride is selected from the compounds used in the known alkaline polymerization method of lactams, and the amount is 0.1 to lactams.
3 mol%, preferably 0.3 to 2.5 mol%, is added to and mixed with a monomeric lactam which is made into a liquid by heating (hereinafter referred to as liquid A).

Specific examples of the bifunctional organic isocyanate used as the activator include hexamethylene diisocyanate, 4,4-diphenylmethane diisocyanate, 2,
4-toluene diisocyanate or the like is selected. Examples of monofunctional isocyanates used in combination with this bifunctional isocyanate include phenyl isocyanate, cyclohexyl isocyanate, and naphthyl isocyanate.

At this time, in determining the mixing ratio of the bifunctional / monofunctional isocyanate, if the mixing ratio of the monofunctional is low, the molecular weight of the polymer to be obtained becomes high and the secondary molding becomes difficult. On the other hand, when the mixing ratio of the bifunctional is low, there is a problem that the amount of residual monomer increases due to the influence of moisture from the melt-coated resin and the influence of decomposition gas and the yield decreases.
Therefore, it is necessary to determine the compounding ratio that satisfies these contradictory conditions. According to the experiment, the mixing ratio of monofunctional / monofunctional + bifunctional isocyanate: 0.1 to 0.9,
More preferably, 0.3 to 0.7 is a suitable blending ratio.
Further, the total amount of this organic isocyanate is 0.2 to 3
Mol%, preferably 0.5 to 2.0 mol% is heated and added to the liquid monomeric lactams and mixed (hereinafter referred to as liquid B).

Inorganic fibers such as glass fibers and carbon fibers, and organic fibers such as polyester can be used as the reinforcing fibers.

The thermoplastic resin used in the coating layer is compatible with the polymerization product, has a softening point of at least 120 ° C. or higher in consideration of the temperature during anionic polymerization, and is a resin having a high resistance to the reaction solution. good. Specifically, polyamide resin, polyamide / polypropylene, polyamide / P
Alloy resins such as PO and polyamide / ABS can be covered.

[0018]

By using sodium hydride as the anionic polymerization catalyst in the liquid A, the catalytic activity can be stabilized. Further, by using a bifunctional organic isocyanate as an activator in the liquid B, the anionic polymerization rate is increased, and the polymerization reaction is stably performed without being affected by the polymerization inhibitor such as water and decomposition gas from the melt-coated resin. While being completed and reducing the residual monomer, the degree of polymerization of the polymer can be controlled low due to the presence of the monofunctional organic isocyanate.

[0019]

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, 1 mol% as an anionic polymerization catalyst with respect to ε-caprolactam as a monomer heated to 80 ° C.
Tank 1 containing the liquid A mixed with sodium hydride and mixed with 0.5 mol% of hexamethylene diisocyanate (hereinafter abbreviated as HDI) as an activator and heated to 80 ° C. % Phenylisocyanate (hereinafter abbreviated as PhNCO) B
A tank 2 containing the liquid was prepared.

A mixing section 3 was provided below the tanks 1 and 2, and the reaction solution was prepared by mixing the solutions A and B at a ratio of 1: 1. The reaction liquid prepared in the impregnation chamber 4 connected to the lower portion of the mixing section 3 is continuously supplied, and the glass fiber 5 made of glass roving, which is the reinforcing fiber that has been dried, is guided into the impregnation chamber 4. The glass fiber 5 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 a solution impregnating portion 7 has a length of 500 mm and an inner diameter of The conical shape was squeezed to 10 to 3 mm, and the one having a curved tube structure as shown in FIG. 2 was used so that there was no backflow and retention of the reaction solution.

The outlet side of the impregnating portion 7 has a guide portion 9 having an inner diameter of 3 mm, and is connected to the pipe 10 by hot water.
It is connected to the nipple 11 held at 0 ° C.

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

The resin coating obtained in the above steps is immediately introduced into a cooling water tank 17 to cool the surface coating layer 14, and then in a polymerization tank 18 having a length of 30 m and controlled at 170 to 200 ° C. The reaction liquid is continuously polymerized with, cooled with water in the cooling water tank 19, and then taken up by the take-up machine 20, and then the cutter 21.
It was cut into about 10 mm and pelletized.

This composition was subjected to Soxhlet extraction with methanol as a solvent to remove residual monomers. The amount of residual monomer was calculated from the weight of the polymerized polyamide before and after the extraction with respect to the initial amount of lactam raw material. Further, the number average molecular weight was measured by a viscosity method. The results are collectively shown in Table 1.

Next, the composition after removal of the residual monomer was fed to an injection molding machine having a screw diameter of 38 mm to give an external shape of 12.
Bending test piece of 4 × 126 mm and thickness of 6.4 mm and 1
A dumbbell-shaped tensile test piece having a size of 2.7 × 181 mm and a thickness of 3.2 mm was molded, and bending strength, bending elastic modulus, tensile strength, and Izod impact strength were measured. The results are shown in Table 2. The molding conditions for the test piece are injection pressure of 1000 Kg.
/ Cm ² , mold temperature 80 ° C, screw rotation speed 30 rp
m, cooling time 45 seconds, injection time 5 seconds.

Example 2. HDI 0.2 as activator
A resin composition was obtained under the same production conditions as in Example 1 except that 5 mol% and PhNCO were changed to 0.5 mol%, and the residual monomer amount and the average molecular weight were measured. The results are collectively shown in Table 1 below.

Example 3. HDI 0.5 as activator
A resin composition was obtained under the same production conditions as in Example 1 except that mol% and PhNCO were changed to 0.25 mol%, and the residual monomer amount and the average molecular weight were measured. The results are collectively shown in Table 1 below.

Comparative Example 1. HDI only 1 as activator
A resin composition was obtained under the same production conditions as in Example 1 except that the content was mol%, and the residual monomer amount, average molecular weight, and mechanical strength were measured. The results are collectively shown in Tables 1 and 2 below.

Comparative Example 2. A resin composition was obtained under the same production conditions as in Example 1 except that only PhNCO was used as the activator at 1 mol%, and the residual monomer amount and the average molecular weight were measured. The results are collectively shown in Table 1 below.

[0032] From Table 1, it is shown that Comparative Example 1 has less residual monomer, but the average molecular weight is almost twice that of Examples 1, 2, and 3. Further, it can be confirmed that the molecular weight of Comparative Example 2 is small, but the amount of residual monomer reaches about 2.5 to 3 times that of Examples 1, 2, and 3.

[0033] As is clear from Table 2 above, in Example 1, the residual fiber length after molding is long, and the physical properties in the molded state are higher than in Comparative Example 1 except for the flexural modulus. This is because the degree of polymerization is low, so that the fluidity at the time of molding is good and the reinforcing fibers are not damaged. The relationship between the injection pressure and the filling amount is shown in FIG. According to this, it is shown that the composition of Example 1 having a smaller molecular weight has a higher filling rate under the same injection pressure and better fluidity than Comparative Example 1.

Fiber-reinforced thermoplastic resin obtained by the present invention
For the fat, the reinforcing fiber is sufficiently impregnated with the low-viscosity monomer reaction liquid.
Since it is manufactured by a method of polymerizing after
Impregnation / wetting of existing resin is the same as conventional fiber-reinforced thermoplastic resin
Remarkably improved, the reinforcing effect of the reinforcing fiber on the resin
Can be fully demonstrated. As a mechanical property with a remarkable reinforcing effect
The durability against repeated stress for a long period of time is mentioned.

Example 4. For long-term cyclic stress
Plane bending fatigue test to evaluate the durability of test materials
(JIS K7119, constant stress amplitude method) was performed.

Carbon fiber reinforced porous material used as a test material
The amide resin composition was used in Example 1 with the reinforcing fiber.
Instead of glass roving, carbon fiber
Under the same manufacturing conditions as in Example 1 except that
Lett was prepared and the residual monomer was removed, and it was prepared. Supplement
The strong fiber content was 40 wt%.

The pellets obtained were screw diameter 38 mm.
Dumbbell-shaped test piece (9.9 x
181 x 3.2 mmt) and molded into a width of 8 mm.
The sample was cut to form a No. I type test piece.

Next, in an atmosphere of 23 ° C., a repetition rate of 1 per minute
800 times, load stress 1500-1750 Kg / cm ²
Repeated bending test with both ends in the range of
Was measured. The results are shown in Table 3.

Reference Example 1. As a commercially available fiber-reinforced thermoplastic resin, using a trading card 3101T-40 (manufactured by Toray, carbon short fiber reinforced nylon 6,6, reinforcing fiber content 40 wt%), a test piece was prepared in the same manner as in Example 4 and loaded. stress
Except that the range of 1250-1625 Kg / cm ² was set.
Repeated bending test similar to that of Example 4 was performed and the test piece broke.
The number of times until it was measured was measured. The results are shown in Table 3.

Reference Example 2. With commercially available fiber-reinforced thermoplastics
And then, Cell Strand Carbon (Hoechst Celanese
Made of carbon long fiber reinforced nylon 6,6, reinforced fiber included
Test piece in the same manner as in Example 4 using
Create and set the load stress range to 1250-1625 Kg / c
Repeated bending test similar to that in Example 4 except that m ² was performed.
The number of times until the test piece was broken was measured. Table of results
3 shows.

[0041] Based on the results in Table 3, the fatigue strength was calculated as 10 ⁷ time strength.
The result is as follows.

[0042]

As described above in detail with reference to the examples, according to the production method of the present invention, the use of a bifunctional organic isocyanate as the activator in the solution B increases the anionic polymerization rate, resulting in melt coating. While the polymerization reaction is completed stably without being affected by the polymerization inhibitor such as water or decomposition gas from the resin, and the residual monomer is reduced,
The presence of the monofunctional organic isocyanate makes it possible to control the degree of polymerization of the polymer to a low level, so that the obtained long-fiber-reinforced polyamide resin composition can be produced with a higher yield than before, but has good fluidity during secondary molding. Therefore, there is an advantage that productivity is improved and a molded product having high strength can be obtained without defective filling or breakage of reinforcing fiber.

[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.

FIG. 3 is a graph comparing the relationship between the injection pressure and the filling amount when the resin compositions obtained in Example 1 and Comparative Example 1 are injection molded.

[Explanation of symbols] 3 mixing chamber 4 impregnation chamber 5 reinforcing fiber (glass fiber) 11 nipple 14 coating layer 18 polymerization tank 20 take-up machine 21 cutter 30 die head

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

Claims (1)

[Claims] 1. A liquid lactam containing sodium hydride as an anionic polymerization catalyst, and a liquid lactam containing a mixture of a bifunctional organic isocyanate and a monofunctional organic isocyanate as an activator. The mixture liquid is supplied to the impregnation chamber while being mixed at a ratio, the long fiber-like reinforcing fibers continuously supplied in the impregnation chamber are impregnated in the mixed liquid, and then the mixture liquid is impregnated with the mixture liquid through a nipple. And the thermoplastic resin having a softening point of at least 120 ° C. is melt-coated on the outer periphery of the impregnated reinforcing fiber to form a seamless coating layer, which is then introduced into a heated polymerization chamber and the inside of the coating layer is introduced. A method for producing a long-fiber-reinforced polyamide resin composition, which comprises anionically polymerizing the lactams and then cutting the lactams to a predetermined length.