JP4949913B2 - Long glass fiber reinforced polyamide resin pellets and molded articles thereof - Google Patents

Description

  The present invention relates to a long glass fiber reinforced polyamide resin pellet excellent in impregnation property, impact property and antifreeze resistance at high temperatures, and a molded product thereof.

Polyamide resins are used in various industrial fields by taking advantage of their excellent mechanical properties and heat resistance. Particularly in the vicinity of an automobile engine, high reliability is required for the material as a mechanical component. Therefore, a so-called reinforced polyamide resin in which mechanical properties are further improved by reinforced glass fiber is preferably used. Of these parts, a polyamide resin material excellent in long-term heat resistance and chemical resistance is desired for parts that are likely to come into contact with antifreeze around the radiator and road anti-freezing material.
For example, the presence of a copper-based stabilizer in both polyamide layers of a composition comprising polyamide 66 resin, higher aliphatic polyamide resin, and glass fiber provides excellent mechanical properties such as tensile strength and flexural modulus, as well as heat resistance. It has been proposed to obtain a composition and a molded body excellent in aging properties, environmental stress crack resistance, and antifreeze resistance (see, for example, Patent Document 1).

However, in the above method, since the polyamide 66 resin and the higher aliphatic polyamide resin are kneaded with an extruder using chopped strands as glass fibers, the fibers break during the kneading with the extruder, and have high mechanical properties. Not satisfying the request.
On the other hand, as a method for fully drawing out the inherent performance of the fibrous reinforcing material to be blended, it has been studied to lengthen the reinforcing fibers (see, for example, Patent Documents 2 and 3). As such a long glass fiber reinforced polyamide resin, for example, it is obtained by a pultrusion method in which a resin strand is impregnated while pulling a resin strand from a roving of glass fiber, and compared with the short fiber reinforced polyamide resin, the mechanical strength is increased. Are better.

However, the long glass fiber reinforced polyamide resin simply using the polyamide 66 resin has insufficient antifreeze resistance, and the long glass fiber reinforced polyamide resin using the higher aliphatic polyamide resin has long-term heat resistance. Since it is inferior, the strength reduction in a high temperature environment is remarkable.
To make up for the short glass fiber reinforced polyamide resin by simply combining the polyamide 66 resin and the higher aliphatic polyamide resin to make up for the drawbacks of both resins, the compatibility between the polyamide 66 resin and the higher aliphatic polyamide resin is poor. Therefore, only pellets with poor impregnation properties can be obtained, and there is a problem that sufficient mechanical strength cannot be obtained.

Also, a method of producing a long glass fiber reinforced polyamide resin pellet made of polyamide 66 resin (or higher aliphatic polyamide resin) and blending with higher aliphatic polyamide resin (or polyamide 66 resin) pellets to obtain a molded product, polyamide 66 A method of obtaining a molded body by blending a long glass fiber reinforced polyamide resin pellet made of resin and a long glass fiber reinforced polyamide resin pellet made of a higher aliphatic polyamide resin is also conceivable. In either method, the polyamide 66 resin and the higher fat are considered. Since the compatibility of the group polyamide resin is insufficient, there is a problem that the antifreeze resistance of the molded body is inferior at a high temperature.
Therefore, in the prior art, a long glass fiber reinforced polyamide resin that satisfies the requirements of pellet impregnation properties, impact properties, and antifreeze resistance at high temperatures has not been obtained.
JP 2003-277604 A JP-A 46-4545 JP 2006-16463 A

  An object of the present invention is to provide a long glass fiber reinforced polyamide resin pellet excellent in impregnation property, impact property, and antifreeze resistance at high temperatures, and a molded product thereof.

  As a result of intensive studies to solve the above problems, the present inventor has found that a glass fiber reinforced polyamide resin comprising a combination of a polyamide 66 resin and a higher aliphatic polyamide resin is a glass fiber (fiber length is less than 5 mm). By including one or more inorganic fillers selected from Wollastonite, Kaolin, Mica, and Talc, long glass fiber reinforced polyamide resin pellets excellent in pellet impregnation properties, impact properties, and antifreeze resistance at high temperatures, and It was found that the molded product can be obtained.

That is, the present invention is as follows.
(1) (A) polyamide 66 resin,
(B) a higher aliphatic polyamide resin having a ratio (CH ₂ / NHCO) of the number of methylene groups to the number of amide groups in the polymer main chain of 6 to 11;
(C) one or more inorganic fillers selected from glass fiber (fiber length less than 5 mm), wollastonite, kaolin, mica, and talc,
(D) a glass fiber having a fiber length equal to or longer than the pellet length,
(A) to (D) glass long fiber reinforced polyamide resin pellets comprising components (A), (B), (C), and (D) components in amounts of A mass%, B mass%, and C, respectively. A glass characterized by satisfying A + B + C + D = 100, 10 ≦ A ≦ 50, 10 ≦ B ≦ 50, 0.5 ≦ C ≦ 3, and 20 ≦ D ≦ 75 when mass% and D mass% are satisfied. Long fiber reinforced polyamide resin pellets.

(2) The glass long fiber reinforced polyamide resin pellet according to (1), wherein the mass ratio of the components (A) and (B) is 0.5 ≦ B / A ≦ 2.
(3) The mass ratio of the components (A), (B), and (C) is 0.015 ≦ C / (A + B) ≦ 0.05, as described in (1) or (2) Long glass fiber reinforced polyamide resin pellets.
(4) The glass long fiber reinforced polyamide resin pellet according to any one of (1) to (3), wherein the component (C) is glass fiber (fiber length is less than 5 mm).
(5) The glass long fiber reinforced polyamide resin pellet according to any one of (1) to (4), wherein the length of the glass long fiber reinforced polyamide resin pellet is 5 to 20 mm.
(6) A long glass fiber reinforced polyamide resin molded product using the long glass fiber reinforced polyamide resin pellets described in (1) to (5).
(7) Automobile underhood parts using the glass long fiber reinforced polyamide resin pellets described in (1) to (5).

(8) a step of melt-kneading the components (A), (B) and (C);
Impregnating the molten resin into a glass fiber roving to obtain a strand;
The method for producing a long glass fiber reinforced polyamide resin pellet according to (1), wherein the strand is obtained by pelletizing the strand to obtain a pellet.
(9) (A), (B) and (C) a step of melt-kneading the components;
Impregnating the molten resin into the glass fiber roving;
Taking a glass fiber impregnated with the resin while twisting to obtain a strand;
The method for producing a long glass fiber reinforced polyamide resin pellet according to (1), wherein the strand is obtained by pelletizing the strand to obtain a pellet.

  According to the present invention, the long glass fiber reinforced polyamide resin comprising a combination of polyamide 66 resin and higher aliphatic polyamide resin is selected from glass fiber (fiber length is less than 5 mm), wollastonite, kaolin, mica, and talc. By containing one or more inorganic fillers, a long glass fiber reinforced polyamide resin pellet excellent in impregnation property, impact property, and antifreeze resistance at high temperature and a molded product thereof can be obtained. Therefore, it can be suitably used for automobile underhood parts that require strict reliability.

The present invention will be specifically described below.
As the polyamide 66 resin of the component (A) used in the present invention, a polyamide other than polyamide 66 may be used as a copolymer with other forming monomers or a blend with other polyamides in a range of less than 15% by mass. . Examples of such a copolymer and blend include a copolymer of polyamide 66 and polyamide 6, polyamide 10, polyamide 12, polyamide 6I, polyamide 6T and / or polyamide MDX6, or a blend. Among them, polyamide 66 is preferable.

The sulfuric acid relative viscosity (ηr) of the polyamide 66 resin is not particularly limited, but is preferably 1.50 to 4.50, more preferably 1.75 to, from the viewpoints of toughness, mechanical strength, and moldability. It is 4.25, more preferably 2.00 to 4.00. Here, the sulfuric acid relative viscosity (ηr) of the polyamide resin is measured at 25 ° C. using an Ostwald viscometer and is obtained by the following equation.
(Ηr) = (Polyamide resin solution dropping seconds) / (Sulfuric acid solution dropping seconds)
The polyamide resin solution used here is obtained by dissolving the polyamide resin in a 96% sulfuric acid solution to a concentration of 0.01 g / ml.

The higher aliphatic polyamide resin (B) used in the present invention is a linear polymer having an amide bond. Examples of such polyamides include polyamide 7, polyamide 9, polyamide 11, polyamide 12, polyamide 69, polyamide 610, polyamide 612, polyamide 1212 and the like, and mixtures thereof. Among these, polyamide 612 is preferable.
The sulfuric acid relative viscosity (ηr) of the higher aliphatic polyamide resin (B) is not particularly limited, but is preferably 1.50 to 4.50 from the viewpoints of toughness, mechanical strength, and moldability. More preferably, it is 1.75-4.25, More preferably, it is 2.00-4.00.

As the inorganic filler of the component (C) used in the present invention, one or more kinds are selected from glass fiber (fiber length is less than 5 mm), wollastonite, kaolin, mica, and talc. Among these, glass fiber (fiber length is less than 5 mm) is preferable from the viewpoint of preventing breakage of long fibers during molding.
As the inorganic filler which is the component (C), in order to improve the adhesion between the inorganic filler and the polyamide resin interface, those subjected to surface treatment with a coupling agent or the like are preferably used.

  As specific examples of glass fibers (fiber length of less than 5 mm), chopped strands and milled fibers usually used for polyamide resins, and chopped strands having an irregular cross-sectional shape that is an eyebrows shape or an oval shape are used. Among them, it is preferable to use chopped strands. As a chopped to be used, an average glass fiber diameter is 7-17 micrometers, More preferably, it is 10-13 micrometers. Regarding the glass fiber length, if the fiber length in the pellet is less than 5 mm, the fiber length of the chopped strand to be used is not limited, but it is particularly preferable to use a chopped strand having a fiber length of less than 1 to 5 mm. 1.5 to 4.5 mm is more preferable.

Wollastonite has the chemical name calcium metasilicate and is a mineral of white needle-like crystals. Usually, it contains 40 to 60% by mass of SiO ₂ and 40 to 55% by mass of CaO, and other components such as Fe ₂ O ₃ , Al ₂ O ₃ , MgO, Na ₂ O and K ₂ O. is there.
Wollastonite having an oil absorption of 20 to 50 cc / 100 g, a bulk specific gravity of 0.1 to 1.0, a fiber length of 0.1 to 1000 μm, and an average particle size of 0.1 to 50 μm can be used.

As used herein, the average particle diameter is determined by using a laser diffraction / scattering particle size distribution device or the like for wollastonite that has been stirred and optionally further dispersed in pure water irradiated with ultrasonic waves so that the transmittance is 85%. The particle diameter corresponding to 50% of the cumulative particle size distribution in the method derived using the method is shown.
These wollastonites can be used in the form of pulverized, classified in some cases, or synthetic products. In addition, those having a Hunter whiteness of 60 or more and a pH value of 6 to 8 when the slurry is made into 10% slurry in high-purity water in the sense that the weather resistance to polyamide is not deteriorated can be preferably used.

Talc is represented by a chemical formula of 4SiO ₂ .3MgO.H ₂ O and is called hydrous magnesium silicate. Usually, talc ore is pulverized by various methods, and those having a particle size of about 0.1 to 20 μm are used as plastic fillers. A preferable talc particle size is 0.5 to 5 μm.
Kaolin has a chemical composition of Al ₂ Si ₂ O ₅ (OH) ₄ , and there are kaolinite, dickite, nacrite, and halloysite, which are different from each other in the two-octahedral 1: 1 layer stacking method, and any of them can be used. Usually, the kaolin blended with the polyamide is preferred from the viewpoint of reducing the volatile components of the molded body and improving the stability during processing of the molded body, because the calcined kaolin having a dehydrated structure. A particle size of usually about 0.1 to 3 μm is preferably used. Moreover, the higher the whiteness, the less the influence on the color tone of the molded product, which is preferable.

Mica varies in crystal structure and chemical composition depending on the production area and synthesis method, but is not particularly limited. The main component of the mica used in the present invention is SiO ₂ , and the crystal structure is such that the SiO ₄ tetrahedron is connected in a hexagonal mesh plate shape, and this plate is a set of two sheets. Further, ions having octahedral positions (for example, Al ³⁺ , Mg ²⁺ ) are ionically bonded between the plates. This is called a tablet, which is stacked in layers, and ions of alkali metal or alkaline earth metal (for example, K ⁺ , Li ⁺ , Na ⁺ ) are ion-bonded between the tablets.
Mica includes muscovite, phlogopite, biotite, and artificial mica. Any of these may be used, but muscovite and artificial mica that are closer to white are preferably used. Mica is pulverized into flakes using the weak ionic bond between tablets. Since the rigidity of a molded object can be improved so that the ratio with respect to the width | variety of this thickness is high, it can use preferably. In general, mica having a particle diameter of about 1 to 30 μm is preferably used because it has a good balance between appearance and rigidity.

Glass fiber roving is preferably used as the glass fiber having a fiber length equal to or longer than the pellet length (D) used in the present invention.
The glass fiber roving is not particularly limited as long as it is a roving obtained by bundling single fibers. In order to improve the adhesion between the glass fiber and the polyamide resin interface, it is preferable that a surface treatment is performed with a coupling agent or the like.
The glass fiber roving preferably used in the present invention is surface-treated with a sizing agent for polyamide resin. The sizing agent here preferably contains a sizing component for the purpose of sizing and a surface treatment component for the purpose of adhesion between the polyamide resin.

The constituents of the glass fiber sizing agent suitably used in the present invention are not particularly limited. The most preferred sizing agent is mainly composed of a copolymer of maleic anhydride and an unsaturated monomer and an amino group-containing silane coupling agent from the viewpoint of improving mechanical properties.
Specific examples of the copolymer of maleic anhydride and unsaturated monomer constituting the sizing agent include styrene, α-methylstyrene, butadiene, isoprene, chloroprene, 2,3-dichlorobutadiene, and 1,3-pentadiene. And a copolymer of an unsaturated monomer such as cyclooctadiene and maleic anhydride. Among these, a copolymer of butadiene or styrene and maleic anhydride is particularly preferable. Furthermore, two or more of these monomers may be used in combination. The copolymer of maleic anhydride and unsaturated monomer preferably has an average molecular weight of 2,000 or more. Further, the ratio of maleic anhydride and unsaturated monomer is not particularly limited. Further, in addition to the maleic anhydride copolymer, an acrylic acid copolymer or a urethane polymer may be used in combination.

As the silane coupling agent which is another component constituting the sizing agent, a silane coupling agent usually used for the surface treatment of glass fibers can be used.
Specifically, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane, N-β (aminoethyl) aminopropyltrimethoxysilane, N An aminosilane coupling agent such as β- (aminoethyl) aminopropyltriethoxysilane;
Epoxysilane coupling agents such as γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane; γ-methacryloxypropylmethyldimethoxysilane, γ- Methacryloxysilane coupling agents such as methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, γ-methacryloxypropyltriethoxysilane;
Vinylsilane coupling agents such as vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (βmethoxyethoxy) silane;
Etc.

Two or more of these coupling agents can be used in combination. Of these, aminosilane coupling agents are most preferred because of their affinity for polyamide resin, and among them, γ-aminopropyltriethoxysilane and N-β (aminoethyl) γ-aminopropyltriethoxysilane are most preferred. The ratio of the maleic anhydride copolymer and the silane coupling agent used is preferably 0.01 to 20 parts by mass, more preferably 5 to 20 parts by mass, and still more preferably 100 parts by mass of the former. Is a ratio of 10 to 20 parts by mass.
Usually, a maleic anhydride copolymer and a silane coupling agent are mixed in an aqueous solvent and used as a sizing agent. Furthermore, surfactants, lubricants, softeners, antistatic agents, etc. may be added as necessary.

Moreover, the average fiber diameter of glass fiber is not specifically limited. It is preferably 5 μm or more from the viewpoint of converging property and resin impregnation property, 20 μm or less from the viewpoint of improving mechanical strength, and more preferably an average diameter of 8 to 17 μm. The number of bundles of glass fibers is not particularly limited, but from the viewpoint of productivity, 1,000 to 10,000 monofilaments, more preferably 1,500 to 8,000, still more preferably 2,000 to A glass fiber roving with 6,000 bundles is preferred.
(D) The fiber length of a component becomes more than pellet length. During production, when the strand is twisted, the length becomes longer than the pellet length, and when the strand is pulled without being twisted, it becomes substantially equal to the pellet length.

Various additives can be blended in the long glass fiber reinforced polyamide resin pellets of the present invention within a range that does not impair the object of the present invention.
Specific examples of additives include heat stabilizers for polyamides such as copper compounds and phosphorus compounds, antioxidants such as hindered phenols and hindered amines, light stabilizers such as manganese compounds, and higher grades represented by metal stearates. Examples thereof include lubricants such as fatty acid metal salts, colorants such as carbon black, titanium oxide, azine dyes and phthalocyanine dyes, plasticizers, antistatic agents, and flame retardants.
Although there is no restriction | limiting in particular in the method of adding these additives, For example, the method of adding at the time of superposition | polymerization of a polyamide resin, and the method of adding in the molten polyamide resin when melt-kneading with a twin-screw extruder can be illustrated.

The length of the long glass fiber reinforced polyamide resin pellets in the present invention is preferably 5 mm or more from the viewpoint of mechanical properties and 20 mm or less from the viewpoint of plasticizing property at the time of molding. It is preferable that it is 20 mm or less from a viewpoint of the dispersibility of the glass fiber at the time of shaping | molding. More preferably, it is the range of 6-18 mm, More preferably, it is the range of 7-15 mm.
In the present invention, the glass long fiber reinforced polyamide resin pellets are produced by melting (A) polyamide 66 resin, (B) higher aliphatic polyamide resin, and (C) inorganic filler using a single or twin screw extruder. It is possible to exemplify kneading and then impregnating the molten resin into a glass fiber roving to obtain a strand, and pelletizing the strand.
The compatibility of (A) polyamide 66 resin and (B) higher aliphatic polyamide resin is improved by blending (C) inorganic filler with (A) polyamide 66 resin and (B) higher aliphatic polyamide resin. When the glass fiber roving is impregnated with the molten resin, the impregnation property of the molten resin into the glass fiber roving is remarkably improved, and a high-quality pellet is obtained.

Specifically, (A) polyamide 66 resin and (B) higher aliphatic polyamide resin are supplied from a feed port (top feed port) located on the most upstream side of the twin screw extruder. (C) There is no restriction | limiting in the supply position of an inorganic filler, You may supply from the feed port located in the most upstream side like resin, and after resin arrives at a molten state, you may side-feed.
An impregnation die for impregnating the molten resin into the glass fiber roving is provided on the most downstream side of the twin screw extruder. The glass fiber roving is passed through the impregnation die and pulled out from the exit of the impregnation die, so that the strand of the glass fiber roving impregnated with the resin is immersed in a water bath and then taken out by a pelletizer and pelletized. It is preferable to install several rollers in the impregnation die for opening the glass fiber and promoting the impregnation.

As a method for further impregnating the glass fiber roving with the resin, it is more preferable to impart a twist to the strand of the glass fiber roving. By imparting twist to the strand, not only the resin impregnation property is enhanced, but also glass fibers gather at the center of the cross section of the strand, and there is an effect of expelling air bubbles existing between the fibers of the glass fiber roving to the outside of the strand cross section. .
Examples of the method for imparting twist include a method in which the exit of the impregnation die is rotated around the axis of the strand by a motor, and a method using a “twisting machine” in which the strand is rotated around the take-up direction of the strand when the strand is taken up. .
Specifically, the “twisting machine” described here has rotating rollers arranged so that the angles of the roller shafts are opposed to each other, and resin is placed on the rollers of the “twisting machine”. The twist can be imparted by passing the impregnated glass fiber roving.
The “twisting machine” is preferably disposed between the water bath and the pelletizer.

The amount of each component used in the present invention is as follows when A + B + C + D = 100.
(A) The compounding quantity of polyamide 66 resin is 10-50 mass%, Preferably it is 15-45 mass%, More preferably, it is 20-40 mass%.
(B) The compounding quantity of higher aliphatic polyamide resin is 10-50 mass%, Preferably it is 15-45 mass%, More preferably, it is 20-40 mass%.
Furthermore, the mass ratio of the (A) polyamide 66 resin and the (B) higher aliphatic polyamide resin is preferably in the range of B / A of 0.5 to 2 from the viewpoint of antifreeze resistance at high temperatures. Preferably it is 0.6-1.8, More preferably, it is 0.7-1.5.

(C) The blending amount of the inorganic filler is 0 from the viewpoint of the compatibility of the (A) polyamide 66 resin and the (B) higher aliphatic polyamide resin at the time of production, and the impregnation of the resin into the glass fiber roving. From the viewpoint of preventing breakage of long fibers during molding, it is 3% by mass or more, and more preferably 0.7 to 2.8% by mass. More preferably, it is 1-2.5 mass%.
Furthermore, the mass ratio of (A) polyamide 66 resin, (B) higher aliphatic polyamide resin, and (C) inorganic filler is preferably 0.015 ≦ C / (A + B) ≦ 0.05, more preferably 0.017. ≦ C / (A + B) ≦ 0.045, more preferably 0.02 ≦ C / (A + B) ≦ 0.04.
(D) The blending amount of the glass fiber having a fiber length equal to or longer than the pellet length is 20 to 75% by mass, preferably 25 to 70% by mass, more preferably 30 to 65% by mass from the viewpoint of mechanical properties. It is a range.

The long glass fiber reinforced polyamide resin pellets of the present invention can be used in known molding processes such as injection molding, extrusion molding, blow molding, and press molding. In a screw type molding machine normally used for injection molding and extrusion molding, in order to suppress the breakage of reinforcing fibers, it is necessary to increase the nozzle and gate shape and use a molding machine screw that takes into account fiber dispersibility. It can be obtained and is preferable.
Since the long glass fiber reinforced polyamide resin pellets of the present invention are excellent in impact resistance and antifreeze resistance at high temperatures, automotive underhood parts requiring strict reliability, such as front end modules, engine covers, and radiator tanks. It is suitably used for car heater tanks, water valves, water pumps, radiator pipes, intake manifolds, timing chain covers, oil pans and the like.

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.
In addition, the raw material and the measuring method which were used for the Example and the comparative example are shown below.
[raw materials]
(A) Polyamide 66 resin Sulfuric acid relative viscosity 2.60
Moisture content 0.09% by mass
Melting point 260 ° C
(B) Polyamide 612 resin Sulfuric acid relative viscosity 2.20
Moisture content 0.09% by mass
Melting point 211 ° C
(C-1) Glass fiber chopped strand T275H manufactured by Nippon Electric Glass Co., Ltd.
Average glass fiber diameter 10μm
Fiber length 3mm
(C-2) Wollastonite Nygros8 made by Nyco
Average particle size 8μm
Fiber length 136μm
(D) Glass fiber roving ER2400T-448N manufactured by Nippon Electric Glass Co., Ltd.
Average glass fiber diameter 17μm, 2400TEX

[Measurement of relative viscosity of sulfuric acid]
A polyamide solution in which 1 g of polyamide resin was dissolved in 100 ml of 96% sulfuric acid was measured with an Oswald viscometer in an environment of 25 ° C., and the relative viscosity of sulfuric acid was obtained from the following formula.
Sulfuric acid relative viscosity of polyamide resin (ηr)
= (Polyamide solution dropping seconds) / (Sulfuric acid solution dropping seconds)

[Measurement of moisture content of polyamide resin]
The moisture content of the polyamide resin pellets before melting was measured according to JIS K 7251 using a moisture meter (CA-06 type) (Karl Fischer method, manufactured by Mitsubishi Chemical Corporation).

[Measurement of impregnation]
One end (cut surface of the strand) of the obtained glass long fiber reinforced polyamide resin pellet (strand cut surface) was adjusted to pH with 1 ml of hydrochloric acid in a propanol solution of methyl red as a color indicator (50 ml of a saturated solution of propanol in methyl red). In this way, the color indicator was infiltrated for 30 minutes, and the penetration state of the color indicator in the length direction of the pellet was observed. Observation was made on 10 arbitrarily selected pellets. The number of pellets in which penetration of the color indicator of 2 mm or more was observed in the length direction of the pellets was determined, and the superiority or inferiority of the impregnation property was determined according to the following criteria. If the glass fiber roving is sufficiently impregnated with the resin, the propanol solution of methyl red will not penetrate into the pellets. That is, the smaller the number of pellets in which penetration of 2 mm or more is observed, the better the impregnation of the resin into the glass fiber roving.
Number of pellets judgment 0 ○
1-5 pieces
6-10 pieces ×

[Measurement of melt viscosity]
In accordance with JIS K 7199, a melt viscosity measuring apparatus (trade name: twin capillary rheometer RH7-2 type, manufactured by Rosand) was used to melt the polyamide resin at the time of impregnation at a melting rate of 1000 sec ⁻¹ . The breaking viscosity was measured.
In addition, the polyamide resin at the time of impregnation here refers to a molten resin that is melt-kneaded by a twin screw extruder and supplied to an impregnation die of a long fiber reinforced resin production apparatus. Moreover, the melting temperature of the polyamide resin at the time of impregnation is defined as the set temperature of the cylinder of the extruder.
When measuring melt viscosity, use the capillary temperature of the capillary rheometer as the melting temperature, and use polyamide resin pellets with the same composition as the molten resin supplied to the impregnation die. If inorganic fillers are included, use polyamide resin pellets blended with inorganic fillers. Measured.
At that time, the orifice had a die diameter of 1.0 mm and a die inflow angle of 180 degrees, and two orifices having an orifice length to orifice diameter ratio L / D of 16 and 0.25 were used to correct the tube length. The thing was made into melt viscosity.

[Measurement of Charpy impact strength]
Using an injection molding machine (trade name: FN-3000, screw diameter 40 mm, manufactured by Nissei Plastic Industry Co., Ltd.), cylinder temperature 290 ° C., mold temperature 80 ° C., injection pressure 65 MPa, injection time 5 sec, cooling time 25 sec, A flat plate (15 cm × 15 cm, thickness 4 mm) was obtained under molding conditions of a screw rotation speed of 200 rpm. One test piece (80 mm × 10 mm, thickness 4 mm) was cut out from the obtained flat plate so that the long side is the flow direction of the resin during molding and the central portion of the flat plate coincides with the central portion of the test piece. . The obtained test piece was notched and the Charpy impact strength was measured according to ISO 180.

[Evaluation of antifreeze resistance]
A flat plate plate used for measurement of the Charpy impact strength was used. A test piece (80 mm × 10 mm, thickness 4 mm) so that the long side of the obtained flat plate is in a direction perpendicular to the flow direction of the resin during molding, and the central portion of the flat plate coincides with the central portion of the test piece. One sheet was cut out. In the autoclave which mix | blended the antifreeze liquid (brand name: Castle long life coolant red V9230-0104, Tacty Co., Ltd.) and water 50:50 (weight ratio), and heated up to 130 degreeC. After the test piece was immersed for 400 hours, the bending strength was measured according to ISO 178.

[Measurement of glass fiber concentration and inorganic filler concentration]
When the filler in the pellet is only glass fiber The glass fiber concentration of the obtained long glass fiber reinforced polyamide resin pellet was measured according to ISO 1172, Method A. Specifically, 2 g of pellets are placed in a porcelain crucible, and polyamide resin is burned using an electric muffle furnace (FP-31 type, manufactured by Yamato Kagaku, set temperature 600 ° C.). Was calculated. Moreover, the glass fiber after combustion is transferred onto a slide glass, all the fibers longer than the pellet length are separated with tweezers, and the mass is measured, so that the fiber length is longer than the pellet length and the fiber length is less than 5 mm. Each concentration was calculated.
-When the filler in a pellet is glass fiber and other inorganic fillers According to ISO 1172 and Method A, the glass fiber concentration and inorganic filler concentration of the obtained long glass fiber reinforced polyamide resin pellets were measured. Specifically, 2 g of pellets are placed in a porcelain crucible and polyamide resin is burned using an electric muffle furnace (FP-31 type, manufactured by Yamato Scientific Co., Ltd., set temperature 600 ° C.). Concentration was calculated.

  The separation method of glass fiber and other inorganic fillers is to transfer all the ash after combustion onto the slide glass, separate all glass fibers longer than the pellet length with tweezers, and measure the mass to determine the fiber length. The glass fiber concentration and inorganic filler concentration above the pellet length were calculated.

[Measurement of weight average glass fiber length]
After putting 2 g of pellets into a porcelain crucible and using an electric muffle furnace (FP-31 type, manufactured by Yamato Kagaku, set temperature 600 ° C.), the polyamide resin is burned, and then the burned glass fibers are transferred onto a slide glass. It is obtained by the following formula from a value obtained by observing under an optical microscope and measuring the length of 400 arbitrarily selected glass fibers using an image analyzer.
Weight average glass fiber length = ΣWi ² / ΣLi
(The length of each glass fiber is L1, L2,... L400, and the weight of each glass fiber is W1, W2,... W400, respectively.)

[Example 1]
Using a twin screw extruder (trade name: ZSK25, manufactured by Coperion), (A) polyamide 66 resin (feed amount 5.75 kg / h), (B) polyamide 612 resin (feed amount 5.75 kg / h) from the top feed port h), (C-1) glass fiber chopped strand (feed amount 0.46 kg / h) is supplied from the downstream side feed port, melt kneaded at a cylinder set temperature of 310 ° C. and a screw rotation speed of 300 rpm, and reinforced long fibers It supplied to the impregnation die | dye which provided the roller for resin impregnations of the resin manufacturing apparatus (KOSLFP-212, Co., Ltd. Kobe Steel Co., Ltd.). The melt viscosity of the polyamide resin at the time of impregnation was 21 (Pa · s).
On the other hand, in (D) glass fiber roving, two glass fiber bundles were introduced from a roving table into an impregnation die cloth head filled with molten polyamide resin. A glass fiber roving bundle impregnated with resin in an impregnation die was continuously drawn out from a nozzle (nozzle diameter 2.9 mm) into a single strand, cooled and solidified in a water-cooled bath, and then pelletized with a pelletizer.

The obtained long glass fiber reinforced polyamide resin pellet (length 10 mm, diameter 2.9 mm) has a glass fiber concentration of 50% by mass (glass fiber less than 5 mm is 2% by mass, pellet length (10 mm) or more glass fiber (fiber Length 10.5 mm) was 48% by mass).
Moreover, when taking up this strand, the strand was rotated around the take-up direction of the strand so that the twist pitch was 28 mm, and twist was imparted.
At this time, the strand take-up speed was 20 m / min, and the production amount of long glass fiber reinforced polyamide resin pellets was 23 kg / h.
The results are shown in Table 1.

[Example 2]
(C-1) Glass fiber A glass fiber reinforced polyamide resin pellet (length 10 mm, diameter 2.9 mm) was obtained in the same manner as in Example 1 except that the supply amount of chopped strand was 0.115 kg / h. It was. The melt viscosity of the polyamide resin at the time of impregnation was 19 (Pa · s). The glass fiber concentration at this time was 50% by mass (0.5% by mass of glass fiber of less than 5 mm, 49.5% by mass of glass fiber having a pellet length (10 mm) or more).
The results are shown in Table 1.

[Example 3]
(C-1) Glass fiber A glass fiber reinforced polyamide resin pellet (length 10 mm, diameter 2.9 mm) was obtained in the same manner as in Example 1 except that the supply amount of chopped strand was 0.69 kg / h. It was. The melt viscosity of the polyamide resin at the time of impregnation was 24 (Pa · s). The glass fiber concentration at this time was 50% by mass (3% by mass of glass fibers of less than 5 mm and 47% by mass of glass fibers having a pellet length (10 mm) or more).
The results are shown in Table 1.

[Example 4]
A glass long fiber reinforced polyamide resin pellet (length: 10 mm, diameter: 2.9 mm) was obtained in the same manner as in Example 1 except that no twist was applied when the strand was taken. The melt viscosity of the polyamide resin at the time of impregnation was 21 (Pa · s). The glass fiber concentration at this time was 50% by mass (2% by mass of glass fiber having a length of less than 5 mm, and 48% by mass of glass fiber having a pellet length (10 mm) or more) (fiber length 10 mm).
The results are shown in Table 1.

[Comparative Example 1]
(C-1) Glass fiber A long glass fiber reinforced polyamide resin pellet (length 10 mm, diameter 2.9 mm) was obtained in the same manner as in Example 1 except that chopped strands were not used. The melt viscosity of the polyamide resin at the time of impregnation was 18 (Pa · s). The glass fiber concentration at this time was 50% by mass (all glass fibers having a pellet length (10 mm) or more).
The results are shown in Table 1. Compared to the Examples, the impregnation properties of the pellets, impact strength, and antifreeze resistance at high temperatures are inferior.

[Comparative Example 2]
(C-1) Glass fiber A glass fiber reinforced polyamide resin pellet (length 10 mm, diameter 2.9 mm) was obtained in the same manner as in Example 1 except that the supply amount of chopped strands was 0.046 kg / h. It was. The melt viscosity of the polyamide resin at the time of impregnation was 19 (Pa · s). The glass fiber concentration at this time was 50% by mass (glass fiber of less than 5 mm was 0.2% by mass, glass fiber having a pellet length (10 mm) or more was 49.8% by mass).
The results are shown in Table 1. Compared to the Examples, the impregnation properties of the pellets, impact strength, and antifreeze resistance at high temperatures are poor.

[Comparative Example 3]
(C-1) Glass fiber Glass fiber reinforced polyamide resin pellets (length: 10 mm, length: 10 mm) in the same manner as in Example 1 except that the supply amount of chopped strand was 1.15 kg / h and the nozzle diameter was 3.0 mm. Diameter 3.0 mm). The melt viscosity of the polyamide resin at the time of impregnation was 29 (Pa · s). The glass fiber concentration at this time was 50% by mass (5% by mass of glass fiber of less than 5 mm and 45% by mass of glass fiber having a pellet length (10 mm) or more).
The results are shown in Table 1. Compared to the examples, the impact strength and antifreeze resistance at high temperatures are inferior.

[Example 5]
(C-1) Glass fiber Glass fiber reinforced polyamide resin pellets (length 10 mm, diameter 2.9 mm) in the same manner as in Example 1 except that (C-2) wollastonite was used instead of chopped strands. ) The melt viscosity of the polyamide resin at the time of impregnation was 20 (Pa · s). The glass fiber concentration at this time was 48% by mass (all glass fibers having a pellet length (10 mm) or more), and the concentration of wollastonite was 2% by mass.
The results are shown in Table 2.

[Comparative Example 4]
(C-2) Glass long fiber reinforced polyamide resin pellets (length 10 mm, diameter 2.9 mm) were obtained in the same manner as in Example 5 except that the supply amount of wollastonite was 0.046 kg / h. . The melt viscosity of the polyamide resin at the time of impregnation was 18 (Pa · s). The glass fiber concentration at this time was 49.8% by mass (all glass fibers having a pellet length (10 mm) or more), and the concentration of wollastonite was 0.2% by mass.
The results are shown in Table 2. Compared to the Examples, the impregnation properties of the pellets, impact strength, and antifreeze resistance at high temperatures are inferior.

[Comparative Example 5]
(C-2) Glass long fiber reinforced polyamide resin pellets (length 10 mm, diameter) in the same manner as in Example 5 except that the supply amount of wollastonite was 1.15 kg / h and the nozzle diameter was 3.0 mm. 3.0 mm). The melt viscosity of the polyamide resin at the time of impregnation was 24 (Pa · s). The glass fiber concentration at this time was 45% by mass (all glass fibers having a pellet length (10 mm) or more), and the concentration of wollastonite was 5% by mass.
The results are shown in Table 2. Compared to the examples, the impact strength and antifreeze resistance at high temperatures are inferior.

[Comparative Example 6]
Using a twin screw extruder (trade name: ZSK25, manufactured by Coperion), (A) polyamide 66 resin (feed amount 5.75 kg / h), (B) polyamide 612 resin (feed amount 5.75 kg / h) from the top feed port h) (C-1) Glass fiber chopped strand (supply amount 11.5 kg / h) is supplied from the downstream side feed port, melt kneaded at a cylinder setting temperature of 310 ° C. and a screw rotation speed of 300 rpm, and from the spinning port The extruded strand was cooled and solidified in a water-cooled bath, and then pelletized with a pelletizer.
The obtained short glass fiber reinforced polyamide resin pellets (length 3 mm, diameter 2.9 mm) had a glass fiber concentration of 50% by mass, and there were no glass fibers having a fiber length longer than the pellet length. (The longest glass fiber length is 0.72 mm, and the weight average glass fiber length is 0.25 mm.)
The results are shown in Table 3. Compared to the examples, the impact strength and antifreeze resistance at high temperatures are inferior.

[Comparative Example 7]
In the twin screw extruder, a glass long fiber reinforced polyamide 66 resin pellet was obtained in the same manner as in Example 1 except that only the (A) polyamide 66 resin (supply amount 11.5 kg / h) was supplied to the top feed port. (Length 10 mm, diameter 2.9 mm) was obtained. The melt viscosity of the polyamide resin during impregnation at this time was 27 (Pa · s). The glass fiber concentration at this time was 50% by mass (all glass fibers having a pellet length (10 mm) or more).
The results are shown in Table 3. Compared to the Examples, the antifreeze resistance at high temperatures is inferior.

[Comparative Example 8]
In the same manner as in Example 1 except that only (B) polyamide 612 resin (supply amount 11.5 kg / h) was supplied to the top feed port of the twin screw extruder and the cylinder set temperature was 280 ° C., the glass length Fiber-reinforced polyamide 612 resin pellets (length 10 mm, diameter 2.9 mm) were obtained.
The melt viscosity of the polyamide resin during impregnation at this time was 38 (Pa · s). The glass fiber concentration at this time was 50% by mass (all glass fibers having a pellet length (10 mm) or more).
The results are shown in Table 3. Compared to the Examples, the antifreeze resistance at high temperatures is inferior.

[Comparative Example 9]
The long glass fiber reinforced polyamide 66 resin pellets obtained in Comparative Example 7 and the long glass fiber reinforced polyamide 612 resin pellets obtained in Comparative Example 8 were mixed at a mass ratio of 1: 1 with a cone-type blender (Platec Co., Ltd., SKD25S type) was used for 10 minutes for pellet blending.
The results of evaluating the blended pellets are shown in Table 3. Compared to the Examples, the antifreeze resistance at high temperatures is inferior.

[Comparative Example 10]
In the twin screw extruder, the same method as in Example 1 was used except that only the (A) polyamide 66 resin (feed amount 5.75 kg / h) was supplied to the top feed port and the nozzle diameter was 2.3 mm. A glass long fiber reinforced polyamide 66 resin pellet (length 10 mm, diameter 2.3 mm, glass fiber concentration 66 mass% (all glass fibers having a pellet length (10 mm) or more)) was obtained. The melt viscosity of the polyamide resin at the time of impregnation was 27 (Pa · s).
Using a cone-type blender at a mass ratio of 3: 1 so that the glass fiber concentration after blending the obtained glass long fiber reinforced polyamide 66 resin pellets and (B) polyamide 612 resin pellets is 50% by mass, 10 Pellet blending was performed for a minute.
The results of evaluating the blended pellets are shown in Table 3. Compared to the Examples, the antifreeze resistance at high temperatures is inferior.

[Comparative Example 11]
In the twin-screw extruder, Example (A) except that (A) polyamide 612 resin (supply amount 5.75 kg / h) was supplied to the top feed port, the cylinder set temperature was 280 ° C., and the nozzle diameter was 2.3 mm. 1 to obtain glass long fiber reinforced polyamide 612 resin pellets (length 10 mm, diameter 2.3 mm, glass fiber concentration 66 mass% (all glass fibers having a pellet length (10 mm) or more)). The melt viscosity of the polyamide resin at the time of impregnation was 38 (Pa · s).
Using a cone-type blender at a mass ratio of 3: 1 so that the glass fiber concentration after blending the obtained long glass fiber reinforced polyamide 612 resin pellets and (A) polyamide 66 resin pellets is 50% by mass, 10 Pellet blending was performed for a minute.
The results of evaluating the blended pellets are shown in Table 3. Compared to the Examples, the antifreeze resistance at high temperatures is inferior.

According to the present invention, a long glass fiber reinforced polyamide resin pellet excellent in impact resistance and antifreeze resistance at high temperatures and a molded product thereof can be provided. Therefore, the present invention is suitably used for automobile underhood parts and the like that require strict reliability.

Claims (8)

(A) polyamide 66 resin,
(B) a higher aliphatic polyamide resin having a ratio (CH ₂ / NHCO) of the number of methylene groups to the number of amide groups in the polymer main chain of 6 to 11;
(C) one or more inorganic fillers selected from glass fiber (fiber length less than 5 mm), wollastonite, kaolin, mica, and talc,
(D) a glass fiber having a fiber length of a pellet length (5 to 20 mm) or more,
(A) to (D) glass long fiber reinforced polyamide resin pellets comprising components (A), (B), (C), and (D) components in amounts of A mass%, B mass%, and C, respectively. A glass characterized by satisfying A + B + C + D = 100, 10 ≦ A ≦ 50, 10 ≦ B ≦ 50, 0.5 ≦ C ≦ 3, and 20 ≦ D ≦ 75 when mass% and D mass% are satisfied. Long fiber reinforced polyamide resin pellets.   2. The glass long fiber reinforced polyamide resin pellet according to claim 1, wherein the mass ratio of the components (A) and (B) is 0.5 ≦ B / A ≦ 2.   3. The long glass fiber reinforced polyamide according to claim 1, wherein the mass ratio of the components (A), (B), and (C) is 0.015 ≦ C / (A + B) ≦ 0.05. Resin pellets.   (C) Component is glass fiber (fiber length is less than 5 mm), The glass long fiber reinforced polyamide resin pellet of any one of Claims 1-3 characterized by the above-mentioned. Long glass fiber-reinforced polyamide resin molded article formed with claim 1-4 long glass fiber-reinforced polyamide resin pellet according. Automotive underhood parts made with claim 1-4 long glass fiber-reinforced polyamide resin pellet according. (A) polyamide 66 resin , (B) higher aliphatic polyamide resin and (C) a step of melt-kneading the inorganic filler ;
Impregnating the molten resin into a glass fiber roving to obtain a strand;
The method for producing a long glass fiber reinforced polyamide resin pellet according to claim 1, wherein the strand is obtained by pelletizing the strand to obtain a pellet. (A) polyamide 66 resin , (B) higher aliphatic polyamide resin and (C) a step of melt-kneading the inorganic filler ;
Impregnating the molten resin into the glass fiber roving;
Taking a glass fiber impregnated with the resin while twisting to obtain a strand;
The method for producing a long glass fiber reinforced polyamide resin pellet according to claim 1, wherein the strand is obtained by pelletizing the strand to obtain a pellet.