JP2001219437A - Method for producing reinforced polyamide resin molding, and reinforced polyamide resin molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a reinforced polyamide resin molding which is light in weight, high in strength, and excellent in appearance. SOLUTION: The molten reinforced polyamide resin is expanded by a method in which after the molten resin is injected/packed in a mold cavity, a mold of at least one part is moved, and the volume of the mold cavity is increased to the volume of the final molding.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to glass fibers and / or glass fibers.
The present invention also relates to a method for melt-molding a reinforced nylon resin containing carbon fibers and a reinforced nylon resin molded product obtained by the method. More specifically, after injecting a molten nylon resin containing glass fiber and / or carbon fiber into a mold cavity, expanding the molten resin, and then taking out the molded product, a light-weight resin molded product having voids therein. And a molded article obtained by the method.

[0002]

2. Description of the Related Art Conventionally, nylon resins containing glass fiber and carbon fiber have been used in electric and electronic fields, automobile fields, construction and
Widely used in the field of civil engineering and general equipment.
Nylon resins containing glass fibers and carbon fibers have the advantage of lower specific gravity than metal products and ceramic products, but further weight reduction is desired from the viewpoint of energy saving. In order to reduce the product weight only, there is a method of reducing the thickness of the product, but there is a practical problem such as a decrease in strength if the thickness is reduced alone, and this alone cannot be used.

[0003] Recently, there is a high need for a reduction in the number of parts and a reduction in weight by modularizing automobile parts, and materials and molding methods that can meet such needs are demanded.

[0004] As a method for reducing the weight of a nylon resin injection-molded article, there has been studied so far, for example, a melt foaming method for molding a foaming agent-containing material ("Practical Plastics Molding Dictionary", Industrial Research Committee). (Eds., Published by the Encyclopedia Publishing Center, pp. 398-400, 1997). In addition, a gas injection molding method for producing a molded article having a hollow portion by injecting a gas after injecting a molten resin less than the mold volume into the mold ("Practical Plastics Molding Encyclopedia", edited by the Industrial Research Council, encyclopedia Published by the Publishing Center, No. 272
277, 1997).

[0005]

However, in the above-mentioned melt foam molding method, the appearance of the molded product is not uniform, for example, it is not possible to uniformly form the end portion of the molded product, or silver (silver) is generated on the surface of the molded product by a foaming agent. There is a problem such as a decrease in Further, in the gas injection molding method, since the hollow portion inside the molded product is large, there is a problem that strength is insufficient, and a flow mark is generated on the surface of the molded product when the timing of gas injection is delayed.

[0006]

In order to solve the above-mentioned problems, a method for producing a reinforced nylon resin molded product of the present invention mainly has the following constitution. That is, a melt of a nylon resin containing glass fiber and / or carbon fiber is injected and filled into the mold cavity, and at least a part of the mold is moved to reduce the volume of the mold cavity to the volume of the final molded product. A method for producing a nylon resin molded product, which comprises expanding the nylon resin melt to expand and removing the molded product after cooling.

[0007] The reinforced nylon resin molded product of the present invention mainly has the following constitution. That is, it is a nylon resin molded product manufactured by the above manufacturing method.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The molding method used in the present invention may be either an injection molding method or an injection compression molding method.

In the present invention, a melt of a nylon resin containing glass fibers and / or carbon fibers is injected or injection-compressed into a mold and filled, and then at least a part of the mold is moved so that the inner volume of the mold is reduced. To the final volume. As a result, a reinforced nylon resin molded product having a uniformly dispersed void can be obtained by expanding to an enlarged volume due to the entanglement of the glass fiber and / or carbon fiber and opening the mold after cooling.

As the mold used in the molding of the present invention, for example, a mold as shown in FIG. 1 is used. A nylon resin melt reinforced with glass fiber and / or carbon fiber is injected or injected into the mold cavity, and then compressed and filled. Then, when the movable mold is retracted to the position where the volume of the final molded article is obtained, the movable mold expands due to a springback phenomenon caused by entanglement with the contained glass fiber and / or carbon fiber, and after cooling, the glass fiber and / or the lightened glass fiber having voids. A nylon resin molded product containing carbon fibers is obtained.

The nylon resin used in the present invention is a polyamide resin containing amino acids, lactams or diamines and dicarboxylic acids as main components. Representative examples of the main components include amino acids such as 6-aminocaproic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid, p-aminomethylbenzoic acid, lactams such as ε-caprolactam and ω-laurolactam, Methylenediamine, hexamerenediamine, 2-methylpentamethylenediamine, undecamethylenediamine, dodecamethylenediamine, 2,2,4- / 2,4
4-trimethylhexamethylenediamine, 5-methylnonamethylenediamine, m-xylylenediamine, p-xylylenediamine, 1,3-bis (aminomethyl) cyclohexane, 1,4-bis (aminomethyl) cyclohexane, 1- Amino-3-aminomethyl-3,5,5-trimethylcyclohexane, bis (4-aminocyclohexyl) methane, bis (3-methyl-4-aminocyclohexyl) methane, 2,2-bis (4-aminocyclohexyl) propane , Bis (aminopropyl) piperazine,
Aliphatic, alicyclic and aromatic diamines such as aminoethylpiperazine, and adipic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, terephthalic acid, isophthalic acid, 2-chloroterephthalic acid, 2-methylterephthalic acid And aliphatic, alicyclic and aromatic dicarboxylic acids such as acid, 5-methylisophthalic acid, 5-sodium sulfoisophthalic acid, hexahydroterephthalic acid and hexahydroisophthalic acid. In the present invention, these raw materials are used. Can be used alone or in the form of a mixture.

In the present invention, a particularly useful nylon resin is a nylon resin having a melting point of 200 ° C. or more and excellent in heat resistance and strength. Specific examples thereof include polycaproamide (nylon 6) and polyhexamethylene. Adipamide (nylon 66), polytetramethylene adipamide (nylon 46), polyhexamethylene sebacamide (nylon 610), polyhexamethylene dodecamide (nylon 612), polyhexamethylene adipamide / polyhexamethylene Terephthalamide copolymer (nylon 66 /
6T), polyhexamethylene adipamide / polyhexamethylene isophthalamide copolymer (nylon 66/6
I), polyhexamethylene adipamide / polyhexamethylene terephthalamide / polyhexamethylene isophthalamide copolymer (nylon 66 / 6T / 6I), polyxylylene adipamide (nylon XD6), polynonamethylene terephthalamide (nylon 9T), polynonamethylene isophthalamide (9I), polynonamethylene terephthalamide / polynonamethylene isophthalamide (9T / 9
I) and mixtures or copolymers thereof. Here, T represents terephthalic acid unit,
I: represents an isophthalic acid unit.

Particularly preferred are nylon 6, nylon 66, nylon 610, nylon 6/66.
Examples thereof include copolymers, nylon 6/12 copolymers, and the like.
It is also practically suitable to use it as a mixture depending on the required properties such as heat resistance and vibration welding properties.

Although the degree of polymerization of these nylon resins is not particularly limited, the relative viscosity of concentrated sulfuric acid is in the range of 1.5 to 6.5,
Particularly, those having a range of 2.0 to 5.0 are preferable. In the present invention, the concentrated sulfuric acid relative viscosity refers to a relative viscosity measured at 25 ° C. in a 1% concentrated sulfuric acid solution.

As the glass fibers and carbon fibers used in the present invention, longer ones have an advantageous effect on mechanical properties, but shorter ones are more advantageous in terms of fluidity during molding. Usually, fibers are broken by a molding process such as compounding or injection molding by an extruder. For this reason, as the fiber length of the glass fiber and carbon fiber in the pellet before molding,
Weight average fiber length (Lw) and fiber diameter (d) ratio (Lw /
d) is preferably in the range of 300 to 50,000, more preferably 500 to 20,000. In addition, Lw / d in the molded product is 20 to 20,
000, more preferably 5
0 to 10,000.

When Lw / d is in the above range, excellent mechanical properties, excellent fluidity at the time of molding, difficulty in entanglement of the fibers, and uniform dispersion are not hindered.

The ratio (Lw / Ln) of the weight average fiber length (Lw) to the number average fiber length (Ln) is preferably 1.1 or more. The fiber diameter is preferably 1 to 30 μm, more preferably 3 to 15 μm.

Here, the weight average fiber length (Lw) and the number average fiber length (Ln) are defined as follows. Weight average fiber length (Lw) = ΣLi ² / ΣLi Number average fiber length (Ln) = ΣLi / n where Li means the length of the ith fiber and n means the number of fibers.

[0019] The fibers are pellets or molded articles of 45%.
It was measured by microscopic observation of 500 or more fibers from the ash remaining after burning in an argon gas atmosphere at 0 ° C. × 5 hours.

The glass fiber and the carbon fiber may be melted and kneaded as a chopped fiber with a nylon resin using an extruder, a kneader, a Banbury mixer, or the like, or a single fiber or a fiber bundle of the glass fiber and the carbon fiber may be formed by a pultrusion method. It may be picked up while impregnating the molten nylon resin. Alternatively, an extruder having a fiber opening / fiber length control mechanism unit in which at least a part of a screw and / or a cylinder is deformed on the surface is used, and a nylon resin is supplied to the extruder and melted, and a continuous state is formed in the molten resin. The fiber is supplied and the fiber is opened and cut by the fiber opening and fiber length control mechanism.
A method of uniformly dispersing in a molten resin and extruding from an extruder is also possible. In this method, roving in which single fibers are bundled is preferably used. The number of bundles is not particularly limited, and a bundle of 10 to 50,000 single filament monofilaments is preferably used in terms of workability. The extruder used in this method is a single-screw or multi-screw extruder in which a continuous fiber is opened and a screw and / or a cylinder is processed so as to control the fiber length. And a mechanism for controlling the degree of fiber opening and the fiber length of the fibrous reinforcing material that is continuous.

The weight of the glass fiber and / or carbon fiber in the nylon resin containing glass fiber and / or carbon fiber used in the production method of the present invention is not particularly limited. From the viewpoint of the specific gravity and strength of the molded product, it is preferably 10 to 90% by weight of the whole. More preferably, it is 10 to 80% by weight, and still more preferably 15 to 70% by weight. Further, glass fiber and carbon fiber may be used in combination, and in that case, the ratio between the two is not particularly limited.

The nylon resin containing glass fibers and / or carbon fibers used in the present invention may contain a small amount of a foaming agent. When the expansion of the glass fiber and / or the carbon fiber is insufficient at the time of molding, it can be surely expanded to the volume of the target molded article by foaming. As the type of the foaming agent, azo type, hydrazine type,
Semicarbazide, azide, triazole, urea, nitroso, oxalic acid, nitrous acid, carbonate, bicarbonate, hydride and the like are used. The amount of the foaming agent added is determined from the viewpoint of preventing appearance defects such as silver (silver).
It is usually at most 5% by weight, preferably at most 3% by weight, more preferably at most 2% by weight.

In the production method of the present invention, a small amount of gas may be injected during molding for the purpose of assisting expansion. The type of gas is not particularly limited as long as there is no deterioration of the molded product and safety during molding is ensured, but an inert gas is usually used. Specifically, nitrogen, argon, carbon dioxide and the like are used. The pressure of the gas is determined according to the size, shape, expansion ratio, melt viscosity of the nylon resin to be used, and the amount of glass fiber and / or carbon fiber to be added, but is usually 0.01 to 50 MPa, Preferably 0.02 to 40
MPa, more preferably 0.05 to 30 MPa.

The resin used in the present invention includes, as long as the effects of the present invention are not impaired, potassium whisker, zinc oxide whisker, aluminum borate whisker, aramid fiber, alumina fiber, silicon carbide fiber, ceramic fiber, asbestos fiber, and the like. Fibrous filler such as stone fiber, metal fiber, etc., wallastite, zeolite, sericite, kaolin, mica, clay, pyrophyllite, bentonite, asbestos, talc, alumina silicate, etc., alumina, silicon oxide, oxidation Metal compounds such as magnesium, zirconium oxide, titanium oxide and iron oxide; carbonates such as calcium carbonate, magnesium carbonate and dolomite; sulfates such as calcium sulfate and barium sulfate; magnesium hydroxide, calcium hydroxide and aluminum hydroxide Hydroxide, glass Non-fibrous fillers such as powders, glass flakes, ceramic beads, boron nitride, silicon carbide, and silica. These may be hollow, or two or more of these fillers may be used in combination. It is. Further, it is not possible to use these fibrous / non-fibrous fillers after pre-treatment with a coupling agent such as an isocyanate compound, an organic silane compound, an organic titanate compound, an organic borane compound, or an epoxy compound.
It is preferable from the viewpoint of obtaining more excellent mechanical strength.

Further, the resin used in the resin molded article of the present invention includes a crystal nucleating agent such as talc, kaolin, an organic phosphorus compound, polyetheretherketone, a coloring inhibitor such as hypophosphite, a hindered phenol. And additives such as antioxidants such as hindered amines, heat stabilizers, lubricants, UV inhibitors, coloring agents such as dyes and pigments, and antistatic agents.

Further, a copper compound can be added for improving the heat resistance of the resin molded product. Specific examples of copper compounds include cuprous chloride, cupric chloride, cuprous bromide, cupric bromide, cuprous iodide, cupric iodide, cupric sulfate, nitric acid Cupric, copper phosphate, cuprous acetate, cupric acetate, cupric salicylate, cupric stearate, cupric benzoate and the inorganic copper halide and xylylenediamine, 2-mercaptobenzimidazole And complex compounds with benzimidazole and the like. Of these, monovalent copper compounds, particularly monovalent copper halide compounds, are preferred, and cuprous acetate, cuprous iodide and the like can be exemplified as particularly suitable copper compounds.

The amount of the copper compound added is sufficient to improve the strength retention during annealing. Usually, 0.01 to 3 parts by weight is required for 100 parts by weight of the resin. Further, it is preferably in the range of 0.015 to 2 parts by weight.

In the present invention, it is possible to add an alkali halide in a form used in combination with a copper compound. Examples of the alkali halide compound include lithium chloride, lithium bromide, lithium iodide, potassium chloride, potassium bromide, potassium iodide, sodium bromide and sodium iodide, and potassium iodide, iodine Sodium chloride is particularly preferred.

In the molding method of the present invention, in order to decorate the surface of the molded article, a surface decorating material may be placed on the inner surface of the mold and molded, thereby eliminating the need for surface painting or decorating after molding. Becomes Specific examples of the surface decoration material include a woven fabric, a nonwoven fabric, a thermoplastic sheet, and a film.

The molded article of the present invention preferably has a rising portion on the outer periphery for the purpose of reinforcing the strength. The molded article of the present invention preferably has a rib structure inside the outer peripheral portion for the purpose of further reinforcing the strength.

The use of the nylon resin molded article to which the production method of the present invention can be applied is not particularly limited, but an instrument panel core, a bumper beam, a door step, a roof rack, a rear quarter panel, an air cleaner case, a front end module, a door module, Automobile parts such as cylinder head covers, exterior wall panels, partition panels,
Used for architectural and civil engineering components such as cable troughs.

The present invention will be described with reference to the drawings. 1 and 2 are conceptual diagrams of the manufacturing method of the present invention. FIG. 1 shows a state immediately after the molten reinforced nylon resin has been injected into the mold cavity, and FIG. 2 shows a state at the time of completion of shaping of the molded product by expanding the cavity volume.

FIGS. 3 and 4 are also conceptual diagrams of the manufacturing method of the present invention, and are conceptual diagrams in a case where gas injection is performed when the cavity volume is enlarged. FIG. 3 shows a state immediately after the molten reinforced nylon resin is injected into the mold cavity, and FIG. 4 shows a state at the time when the cavity volume has been expanded and gas injection has been performed to complete the shaping of the molded article.

[0034]

The present invention will be described more specifically with reference to the following examples. In the examples, the concentrated sulfuric acid relative viscosity ηr is 1
It is a value measured at 25 ° C. using a concentrated sulfuric acid solution having a% concentration. The ratio between the weight-average fiber length (Lw) and the fiber diameter (d) is determined from the ash remaining after burning the pellet or the molded product at 450 ° C. for 5 hours in an argon gas atmosphere.
It is calculated by measuring 1,000 fibers by microscopic observation.

Example 1 Nylon 6 containing 70% by weight of glass fiber having a weight average length of 11 mm and a diameter of 13 μm
Using 6 resin (ηr = 2.90), molding was performed using an injection molding machine having a screw with a mold clamping force of 850 t and a compression ratio of 1.8. The resin temperature was 290 ° C and the mold temperature was 80 ° C. The mold shown in FIG. 1 was used. After 1.8 seconds from the completion of filling, the movable mold C was retracted to the position shown in FIG. 2 to expand the nylon resin, and the thickness was 25.4 mm and 25 m thick.
A plate-shaped molded product of mx 495 mm was molded. Using this molded product, bending characteristics were evaluated in accordance with ASTM D-790. Further, the surface condition of the molded article was visually evaluated. Table 1 shows the results. It can be seen that by using the production method of the present invention, a glass fiber reinforced nylon resin hollow article having a good surface appearance and excellent strength and rigidity can be obtained.

[0036]

[Table 1]

Example 2 Nylon 6 containing 70% by weight of glass fibers having a weight average length of 11 mm and a diameter of 13 μm
Using resin (2.70), mold clamping force 850t, compression ratio 1.
The molding was performed using an injection molding machine having a screw of No. 8. The resin temperature was 255 ° C and the mold temperature was 80 ° C.
The mold used was of the type shown in FIG.
Two seconds later, the movable mold C is retracted to the position shown in FIG. 2 to expand the nylon resin, and has a thickness of 25.4 mm, 25 mm × 49.
A plate-shaped molded product of 5 mm was molded. Using this molded product, A
Flexural properties were evaluated according to STM D-790. Further, the surface condition of the molded article was visually evaluated. Table 1 shows the results
Are shown together. It can be seen that by using the production method of the present invention, a glass fiber reinforced nylon resin hollow article having a good surface appearance and excellent strength and rigidity can be obtained.

[Examples 3 and 4] Weight average length 11 mm,
A molded product was produced in the same manner as in Examples 1 and 2, except that a nylon resin containing 70% by weight of carbon fiber having a diameter of 7 μm was used. Using these molded articles, ASTM D-79
The bending characteristics were evaluated according to 0. Further, the surface condition of the molded article was visually evaluated. The results are shown in Table 1. By using the production method of the present invention, the surface appearance is good,
It can be seen that a hollow carbon fiber reinforced nylon resin product having excellent rigidity can be obtained.

[Examples 5 to 8] Molded articles were produced in the same manner as in Examples 1 to 4, except that the movable mold C was retracted after the filling was completed, and at the same time nitrogen gas of 0.2 MPa was injected from the gas injection port. . Using these molded products, the characteristics were evaluated in the same manner as in Examples 1 to 4. The results are shown in Table 1. In the manufacturing method of the present invention, it can be seen that the surface appearance is further improved by performing gas injection simultaneously with expansion due to movement of the movable mold.

Example 9 A 66/6 copolymer containing 70% by weight of glass fibers having a weight average length of 11 mm and a diameter of 9 μm (copolymerization ratio: 15/85% by weight, ηr = 3.2) was used. Molding was performed using an injection molding machine having a screw with a mold clamping force of 850 t and a compression ratio of 1.8. Resin temperature 220
° C and the mold temperature were 75 ° C. The mold shown in FIG. 1 was used.
Then, the nylon resin was expanded by retracting to the position shown in FIG. 1 to form a molded product having a thickness of 25.4 mm and a size of 25 mm × 495 mm. Using this molded product, bending characteristics were evaluated in accordance with ASTM D-790. Further, the surface condition of the molded article was visually evaluated. The results are shown in Table 1. According to the present invention, it can be seen that a reinforced nylon resin hollow article having a good surface appearance and excellent strength and rigidity can be obtained even when the type of the nylon resin is changed.

Example 10 Except for using a 66/6 copolymer containing 70% by weight of carbon fibers having a weight average length of 11 mm and a diameter of 7 μm (copolymerization ratio: 15/85% by weight, ηr = 3.2) A molded article was manufactured in the same manner as in Example 9. Various characteristics were evaluated using the obtained molded product. Table 1 shows the results
Are shown together. According to the present invention, it can be seen that a reinforced nylon resin hollow article having a good surface appearance and excellent strength and rigidity can be obtained even when the type of the nylon resin is changed.

Example 11 66 / 6T containing 70% by weight of glass fiber having a weight average length of 11 mm and a diameter of 9 μm
/ 6I copolymer (copolymerization ratio 12/62/26% by weight, η
Using r = 2.4), molding was performed using an injection molding machine having a screw with a mold clamping force of 850 t and a compression ratio of 1.8.
The resin temperature was 340 ° C and the mold temperature was 145 ° C. The mold shown in FIG. 1 was used. After 1.8 seconds from the completion of filling, the movable mold C was retracted to the position shown in FIG. 2 to expand the nylon resin, and the thickness was 25.4 mm, 25 mm × 495.
mm was molded. Using this molded product, ASTM
The bending properties were evaluated according to D-790. Further, the surface condition of the molded article was visually evaluated. The results are shown in Table 1. According to the present invention, it can be seen that a reinforced nylon resin hollow article having a good surface appearance and excellent strength and rigidity can be obtained even when the type of the nylon resin is changed.

Example 12 66 / 6T / containing 70% by weight of carbon fibers having a weight average length of 11 mm and a diameter of 7 μm
6I copolymer (copolymerization ratio 12/62/26% by weight, ηr
= 2.4), except that (2.4) was used. ASTM D-
The bending properties were evaluated according to 790. Further, the surface condition of the molded article was visually evaluated. The results are shown in Table 1.
According to the present invention, it can be seen that a reinforced nylon resin hollow article having a good surface appearance and excellent strength and rigidity can be obtained even when the type of the nylon resin is changed.

Example 13 Nylon 6 containing 70% by weight of glass fiber having a weight average length of 7 mm and a diameter of 13 μm
Using 6 resin (ηr = 2.90), molding was performed using an injection molding machine having a screw with a mold clamping force of 850 t and a compression ratio of 1.8. The resin temperature was 290 ° C and the mold temperature was 80 ° C. The mold shown in FIG. 1 was used. After 1.8 seconds from the completion of filling, the movable mold C was retracted to the position shown in FIG. 2 to expand the nylon resin, and the thickness was 25.4 mm and 25 m thick.
A plate-shaped molded product of mx 495 mm was molded. Using this molded product, bending characteristics were evaluated in accordance with ASTM D-790. Further, the surface condition of the molded article was visually evaluated. Table 2 shows the results. Weight average length of glass fiber and carbon fiber (L
Even if the ratio Lw / d of w) to the fiber diameter (d) is small, a reinforced nylon resin hollow article having a good surface appearance and excellent strength and rigidity can be obtained, as compared with Examples 1-4 having a large Lw / d. The strength and rigidity are slightly lower.

[0045]

[Table 2]

Example 14 Nylon 6 containing 70% by weight of glass fiber having a weight average length of 7 mm and a diameter of 13 μm
Using resin (2.70), mold clamping force 850t, compression ratio 1.
The molding was performed using an injection molding machine having a screw of No. 8. The resin temperature was 255 ° C and the mold temperature was 80 ° C.
The mold used was of the type shown in FIG.
Two seconds later, the movable mold C is retracted to the position shown in FIG. 2 to expand the nylon resin, and has a thickness of 25.4 mm, 25 mm × 49.
A plate-shaped molded product of 5 mm was molded. Using this molded product, A
The bending properties were evaluated according to STMD-790. Also,
The surface condition of the molded article was visually evaluated. The results are shown in Table 2. Weight average length of glass fiber and carbon fiber (Lw)
Even if the ratio Lw / d of fiber and fiber diameter (d) is small, a reinforced nylon resin hollow article having a good surface appearance and excellent strength and rigidity can be obtained, but the strength is higher than those of Examples 1 to 4 having a large Lw / d.・
It can be seen that the rigidity is somewhat low.

[Examples 15 and 16] Weight average length 7 m
m and molded articles were produced in the same manner as in Comparative Examples 9 to 10 except that a nylon resin containing 70% by weight of carbon fiber having a diameter of 7 μm was used. ASTM D using these molded products
The bending properties were evaluated according to -790. Further, the surface condition of the molded article was visually evaluated. Table 3 shows the results. Cut out and various characteristics were evaluated. The results are shown in Table 2.
Even if the ratio Lw / d of the weight average length (Lw) and the fiber diameter (d) of glass fiber and carbon fiber is small, a reinforced nylon resin hollow article having a good surface appearance and excellent strength and rigidity can be obtained.
It can be seen that the strength and rigidity are slightly lower than those of Examples 1 to 4 where Lw / d is large.

Example 17 Using the reinforced nylon 66 resin used in Example 1, a front end module having the shape shown in FIG. 5 was manufactured by the manufacturing method of the present invention. A lamp is installed in the gap “G” in FIG. 5, and an engine radiator, an air conditioner radiator, and a cooling fan can be incorporated in the gap “H”. Could be manufactured.

Example 18 Using the reinforced nylon 66 resin used in Example 1, a cylinder head cover having the shape shown in FIG. 6 was manufactured by the manufacturing method of the present invention. FIG.
Ignition coil is installed in the space of "I",
The space of "J" was used for screwing. As a result, a lightweight and highly rigid cylinder head cover could be manufactured.

Comparative Examples 1-4 Masterbatches containing 1 wt% of barium azodicarboxylate as a foaming agent were used.
Molding was performed in the same manner as in Examples 1 to 4, except that 3 parts by weight were dry-blended and directly molded without going through an expansion step.
Using these molded products, bending characteristics were evaluated in accordance with ASTM D-790. Further, the surface condition of the molded article was visually evaluated. Table 3 shows the results. It can be seen that molding in the presence of a foaming agent cannot provide a reinforced nylon resin hollow molded article having excellent surface appearance, strength and rigidity.

[0051]

[Table 3]

[Comparative Examples 5 to 8] Instead of performing the expansion step in Examples 1 to 4, a nitrogen gas of 1 MPa was injected from a gas injection port in synchronization with the filling of the nylon resin to form a hollow molded article. Example 1 using the obtained molded product
The characteristics were evaluated in the same manner as in Nos. 1 to 4. The results are shown in Table 3. It can be seen that reinforced nylon resin molded products with excellent appearance can be obtained by molding only with gas injection, but the strength and rigidity are poor.

[Comparative Example 9] Using a polypropylene (melt index at 230 ° C./2.16 kg load: 30 g / 10 min) containing 70% by weight of glass fiber having a weight average length of 11 mm and a diameter of 13 μm, a mold clamping force of 850 t ,
Molding was performed using an injection molding machine having a screw with a compression ratio of 1.8. Resin temperature 230 ° C, mold temperature 30 ° C
Met. The mold shown in FIG. 1 was used. After 1.8 seconds from the completion of filling, the movable mold C was retracted to the position shown in FIG. 2 to expand the polypropylene resin, and the thickness was 25.4 m.
m, a plate-shaped molded product of 25 mm × 495 mm was molded. Using this molded product, bending characteristics were evaluated in accordance with ASTM D-790. Further, the surface condition of the molded article was visually evaluated. The results are shown in Table 3. It can be seen that a reinforced polypropylene resin molded article having an excellent appearance can be obtained even when polypropylene is used as the resin, but the strength and rigidity are inferior to those of the reinforced nylon resin molded article of the present invention.

Comparative Example 10 A polypropylene containing 70% by weight of carbon fibers having a weight average length of 11 mm and a diameter of 7 μm (melt index at 230 ° C./2.16 kg load: 30 g / 10 min), and a mold clamping force of 850 t The molding was performed using an injection molding machine having a screw having a compression ratio of 1.8. The resin temperature was 230 ° C and the mold temperature was 30 ° C. The mold shown in FIG. 1 was used. After 1.8 seconds from the completion of filling, the movable mold C was retracted to the position shown in FIG. 2 to expand the nylon resin, and the thickness was 25.4 mm and 25 m thick.
A plate-shaped molded product of mx 495 mm was molded. Using this molded product, bending characteristics were evaluated in accordance with ASTM D-790. Further, the surface condition of the molded article was visually evaluated. The results are shown in Table 3. It can be seen that a reinforced polypropylene resin molded article having an excellent appearance can be obtained even when polypropylene is used as the resin, but the strength and rigidity are inferior to those of the reinforced nylon resin molded article of the present invention.

[0055]

By using the production method of the present invention,
A lightweight and high-rigidity reinforced nylon resin molded product that cannot be obtained by the conventional method can be easily obtained.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing a state in which a nylon resin is injected into a mold in the production method of the present invention.

FIG. 2 is a conceptual diagram illustrating a state in which a movable mold is slid back and expanded after a nylon resin is injected into a mold in the manufacturing method of the present invention.

FIG. 3 is a conceptual view showing a state in which a nylon resin is injected into a gas-injectable mold in the production method of the present invention.

FIG. 4 is a conceptual diagram showing a state in which a movable mold is slid back and expanded after injection of a nylon resin into a mold into which gas can be injected in the manufacturing method of the present invention.

FIG. 5 is a conceptual diagram of a front end module of an automobile, which is an example of a molded product manufactured using the manufacturing method of the present invention.

FIG. 6 is a conceptual diagram of a cylinder head cover of an automobile, which is another example of a molded product manufactured by using the manufacturing method of the present invention.

[Explanation of symbols]

 A: fixed type B: movable type C: movable type D: cavity E: gas inlet F: gas outlet G: lamp house H: radiator house I: ignition coil installation hole J: mounting hole

Claims (9)

[Claims] 1. A mold of a nylon resin containing glass fiber and / or carbon fiber is injected and filled into a mold cavity, and at least a part of the mold is moved to a volume of a final molded product. A method for producing a reinforced nylon resin molded product, comprising expanding the cavity volume to expand the nylon resin melt and removing the molded product after cooling. 2. The ratio (Lw / d) between the weight average length (Lw) and the fiber diameter (d) of the glass fiber and / or carbon fiber before melt molding is 300 to 50,000. For manufacturing reinforced nylon resin molded products. 3. Nylon resin is nylon 6, nylon 66, nylon 12, nylon 11, nylon 610,
The reinforced nylon resin molding according to claim 1 or 2, which is at least one selected from the group consisting of nylon 612, nylon 46, nylon 9T, nylon 9I, nylon 6T, nylon 6I, a copolymer thereof, and a blend thereof. Product manufacturing method. 4. A nylon resin having a relative sulfuric acid viscosity of 1.5.
The method for producing a reinforced nylon resin molded product according to any one of claims 1 to 3, wherein 5. A reinforced nylon resin molded product obtained by the production method according to claim 1. 6. The reinforced nylon resin molded product according to claim 5, wherein the molded product has a rising portion on an outer peripheral portion. 7. The reinforced nylon resin molded product according to claim 5, wherein the molded product has a rib structure inside the outer peripheral portion. 8. The ratio (Lw / d) between the weight average length (Lw) and the fiber diameter (d) of the glass fiber and carbon fiber in the molded product is 2
The reinforced nylon resin molded article according to any one of claims 5 to 7, wherein the number is from 0 to 20,000. 9. The molded article is a front-end module,
The reinforced nylon resin molded product according to claim 5, which is one of a door module and a cylinder head cover.