JP2022054099A - Resin composition, molded article and thin wall molded article manufacturing method - Google Patents

Abstract

To provide a resin composition capable of providing a molded article that has a long spiral flow length, is sufficiently crystallized even in low temperature molding and can effectively suppress a mass increase ratio after water immersion while highly maintaining a mechanical strength, and to provide a molded article using the resin composition and a thin wall molded article manufacturing method.SOLUTION: A resin composition contains 80-150 pts.mass of an inorganic fiber, 0.01-2 pts.mass of an aliphatic metal salt, and 0.1-10 pts.mass of an inorganic crystal nucleus agent, with respect to 100 pts.mass of a polyamide resin that is composed of a diamine-derived structural unit and a dicarboxylic acid-derived structural unit, in which, 70 mol% or more of the diamine-derived structural unit is derived from xylylenediamine, and 70 mol% or more of the dicarboxylic acid-derived structural unit is derived from an aliphatic dicarboxylic acid having 9 to 18 carbon atoms.SELECTED DRAWING: None

Description

The present invention relates to a method for producing a resin composition, a molded product and a thin-walled molded product. In particular, the present invention relates to a resin composition containing a polyamide resin and an inorganic fiber.

Polyamide resin, which is a typical engineering plastic, is easy to process and is excellent in mechanical physical properties, electrical properties, heat resistance, and other physical and chemical properties. Therefore, it is widely used for vehicle parts, electrical / electronic equipment parts, other precision equipment parts, and the like.
Among such polyamide resins, a polyamide resin composed of a diamine-derived structural unit and a dicarboxylic acid-derived structural unit in which 70 mol% or more of the diamine-derived structural unit is derived from xylylenediamine has excellent mechanical strength. Therefore, it is widely used for various purposes (for example, Patent Document 1 and the like).

Japanese Unexamined Patent Publication No. 2019-143023

By the way, in recent years, the miniaturization of vehicle parts, electrical / electronic equipment parts, other precision equipment parts, and the like has progressed, and along with this, the demand for thin-walled molded products has progressed. In particular, when a thin-walled molded product is molded by injection molding, excellent fluidity is required in order to ensure that the resin composition is poured to the end of the mold. In addition, electronic devices such as smartphones are also required to have high mechanical strength. Further, low-temperature molding is conceivable in order to improve the fluidity, but low-temperature molding may not sufficiently proceed with the crystallization of the polyamide resin.
Nylon 6 can be considered as a polyamide resin having a long flow length and sufficient crystallization even in low temperature molding, but it is not preferable for applications where excellent low water absorption is required because of its high water absorption rate.
An object of the present invention is to solve such a problem. The present invention has a long spiral flow length while maintaining high mechanical strength, is sufficiently crystallized even in low temperature molding, and has a mass increase rate after immersion in water. It is an object of the present invention to provide a resin composition capable of providing a molded product capable of effectively suppressing the above, and a method for producing a molded product and a thin-walled molded product using the resin composition.

As a result of the study by the present inventor based on the above problems, the polyamide is composed of a diamine-derived structural unit and a dicarboxylic acid-derived structural unit, and 70 mol% or more of the diamine-derived structural unit is derived from xylylene diamine. The above problem can be solved by using a long-chain aliphatic dicarboxylic acid as the dicarboxylic acid in the resin, reducing the amount of the inorganic crystal nucleating agent, and using the fatty acid metal salt as the releasing agent. I found.
Specifically, the above problem was solved by the following means.
<1> Consists of a diamine-derived constituent unit and a dicarboxylic acid-derived constituent unit, 70 mol% or more of the diamine-derived constituent unit is derived from xylylene diamine, and 70 mol% or more of the dicarboxylic acid-derived constituent unit is carbon. 80 to 150 parts by mass of inorganic fiber, 0.01 to 2 parts by mass of fatty acid metal salt, and 0.1 to 10 parts of inorganic crystal nucleating agent with respect to 100 parts by mass of a polyamide resin derived from an aliphatic dicarboxylic acid of 9 to 18. A resin composition comprising parts by weight.
<2> The mass increase rate when the resin composition is molded into a molded product having a thickness of 1.0 mm, dried at 80 ° C. for 48 hours, and then immersed in water at 23 ° C. for 24 hours is 0.45% or less. , <1>.
<3> The resin composition according to <1> or <2>, wherein the inorganic fiber has a cross-sectional aspect ratio of 2 or more.
<4> The resin composition according to any one of <1> to <3>, wherein the inorganic crystal nucleating agent contains at least one selected from talc, mica, calcium carbonate, and boron nitride.
<5> The resin composition according to any one of <1> to <4>, wherein the fatty acid metal salt is a fatty acid metal salt having 20 or more carbon chains.
<6> The content of the polyamide resin is 40% by mass or more and less than 50% by mass, the content of the inorganic fiber is 50 to 60% by mass, and the content of the inorganic crystal nucleating agent is 0. . The resin composition according to any one of <1> to <5>, which is 1 to 4.5% by mass.
<7> When the resin composition is molded into a molded product having a thickness of 1 mm at a mold temperature of 100 ° C., the calorific value of the crystallization peak in the differential scanning calorimetry is 1 J / g or less, or crystallization. The resin composition according to any one of <1> to <6>, wherein no peak is observed.
<8> The total amount of m-xylylenediamine of 10 to 90 mol% and paraxylylenediamine of 90 to 10 mol% (however, the total of methylylenediamine and paraxylylenediamine exceeds 100 mol%). The resin composition according to any one of <1> to <7>, which comprises (1).
<9> The resin composition according to any one of <1> to <8>, wherein the dicarboxylic acid contains sebacic acid and / or 1,12-dodecane diic acid.
<10> The resin composition according to any one of <1> to <8>, wherein the dicarboxylic acid contains 1,12-dodecanedioic acid.
<11> A molded product formed from the resin composition according to any one of <1> to <10>.
<12> A method for producing a thin-walled molded product, which comprises injection molding the resin composition according to any one of <1> to <10>.

INDUSTRIAL APPLICABILITY According to the present invention, a resin composition capable of providing a molded product having a long spiral flow length, sufficiently crystallized even in low temperature molding, and capable of effectively suppressing the mass increase rate after immersion in water while maintaining high mechanical strength. , And a method for producing a molded product and a thin-walled molded product using the resin composition can be provided.

Hereinafter, embodiments for carrying out the present invention (hereinafter, simply referred to as “the present embodiment”) will be described in detail. The following embodiments are examples for explaining the present invention, and the present invention is not limited to the present embodiment.
In addition, in this specification, "-" is used in the meaning which includes the numerical values described before and after it as the lower limit value and the upper limit value.
In the present specification, various physical property values and characteristic values shall be at 23 ° C. unless otherwise specified.

The resin composition of the present embodiment is composed of a diamine-derived structural unit and a dicarboxylic acid-derived structural unit, and 70 mol% or more of the diamine-derived structural unit is derived from xylylene diamine and is a dicarboxylic acid-derived structural unit. 80 to 150 parts by mass of inorganic fiber, 0.01 to 2 parts by mass of fatty acid metal salt, and an inorganic crystal nucleating agent with respect to 100 parts by mass of a polyamide resin derived from an aliphatic dicarboxylic acid having 70 mol% or more of 9 to 18 carbon atoms. It is characterized by containing 0.1 to 10 parts by mass. With such a configuration, it is possible to provide a molded product having a long spiral flow length, sufficiently crystallized even in low temperature molding, and effectively suppressing the mass increase rate after immersion in water, while maintaining high mechanical strength. It will be possible.
When manufacturing a thin-walled molded product, high fluidity is required in order to sufficiently pour the resin composition to the end of the mold by injection molding. In the present embodiment, an aliphatic dicarboxylic acid having 9 to 18 carbon atoms is used as a raw material monomer for the xylylenediamine-based polyamide resin, and the upper limit of the inorganic crystal nucleating agent is adjusted to increase the flow length. It is presumed that it was successful. Further, it is presumed that crystallization is sufficiently promoted even at a low temperature by adjusting the lower limit amount of the inorganic crystal nucleating agent.

<Polyamide resin>
The polyamide resin used in the present embodiment is composed of a diamine-derived structural unit and a dicarboxylic acid-derived structural unit, and 70 mol% or more of the diamine-derived structural unit is derived from xylylene diamine and is a dicarboxylic acid-derived structural unit. 70 mol% or more is a polyamide resin derived from an aliphatic dicarboxylic acid having 9 to 18 carbon atoms. In the present specification, such a polyamide resin may be referred to as "xylylenediamine-based polyamide resin".
By using the xylylenediamine-based polyamide resin, low water absorption of the obtained molded product can be achieved.
The diamine-derived constituent unit of the xylylenediamine-based polyamide resin is more preferably 75 mol% or more, further preferably 80 mol% or more, still more preferably 85 mol% or more, still more preferably 90 mol% or more, still more preferably. Is derived from xylylenediamine in an amount of 95 mol% or more. The upper limit is 100 mol%.
The constituent unit derived from the dicarboxylic acid of the xylylene diamine-based polyamide resin is more preferably 75 mol% or more, further preferably 80 mol% or more, still more preferably 90 mol% or more, still more preferably 95 mol% or more, and carbon. It is derived from an aliphatic dicarboxylic acid having 9 to 18 carbon atoms. The upper limit is 100 mol%.

The xylylenediamine is preferably metaxylylenediamine and / or paraxylylenediamine.
Further, the amount of xylylene diamine is 10 to 90 mol% (preferably 20 mol% or more, more preferably 30 mol% or more, still more preferably 40 mol% or more, still more preferably 50 mol% or more, still more preferably 55 mol%. The above, preferably 80 mol% or less, more preferably 75 mol% or less, and 90 to 10 mol% (preferably 80 mol% or less, more preferably 70 mol% or less, still more preferably 70 mol% or less). It is preferable to contain paraxylylene diamine in an amount of 60 mol% or less, more preferably 50 mol% or less, still more preferably 45 mol% or less, and preferably 20 mol or more, more preferably 25 mol% or more). However, the total of m-xylylenediamine and paraxylylenediamine does not exceed 100 mol%.

Examples of diamines other than metaxylylenediamine and paraxamethylenediamine that can be used as the raw material diamine component of the xylylenediamine-based polyamide resin include tetramethylenediamine, pentamethylenediamine, 2-methylpentanediamine, hexamethylenediamine, and heptamethylene. An aliphatic diamine such as diamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, dodecamethylenediamine, 2,2,4-trimethyl-hexamethylenediamine, 2,4,4-trimethylhexamethylenediamine, 1,3- Bis (aminomethyl) cyclohexane, 1,4-bis (aminomethyl) cyclohexane, 1,3-diaminocyclohexane, 1,4-diaminocyclohexane, bis (4-aminocyclohexyl) methane, 2,2-bis (4-amino) Aromatic rings such as alicyclic diamines such as cyclohexamethylene) propane, bis (aminomethyl) decalin, bis (aminomethyl) tricyclodecane, bis (4-aminophenyl) ether, paraphenylenediamine, and bis (aminomethyl) naphthalene. Examples thereof include diamines and the like, and one kind or a mixture of two or more kinds can be used.

As the aliphatic dicarboxylic acid having 9 to 18 carbon atoms (preferably 9 to 14 carbon atoms) preferable to be used as a raw material dicarboxylic acid component of the xylylene diamine-based polyamide resin, α, ω-straight chain having 9 to 18 carbon atoms It is an aliphatic dicarboxylic acid. Examples of such an aliphatic dicarboxylic acid include aliphatic dicarboxylic acids such as sebacic acid, undecanedioic acid, and dodecanedioic acid, and one kind or a mixture of two or more kinds can be used. From the viewpoint of achieving both mechanical properties and low water absorption, it is preferable to contain sebacic acid and / or 1,12-dodecanedioic acid, and more preferably 1,12-dodecanedioic acid.

Examples of the dicarboxylic acid component other than the aliphatic dicarboxylic acid having 9 to 18 carbon atoms include an aliphatic dicarboxylic acid having less than 9 carbon atoms such as adipic acid, a phthalic acid compound such as isophthalic acid, terephthalic acid, and orthophthalic acid, 1, 2 and 2. -Naphthalenedicarboxylic acid, 1,3-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 1,6-naphthalenedicarboxylic acid, 1,7-naphthalenedicarboxylic acid, 1,8-naphthalene Examples of isomers of naphthalenedicarboxylic acids such as dicarboxylic acid, 2,3-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, and 2,7-naphthalenedicarboxylic acid can be exemplified, and one kind or two or more kinds are mixed. Can be used.

In the xylylenediamine-based polyamide resin in the present embodiment, 0 to 100 mol% (preferably 10 to 90 mol%) of the diamine-derived constituent unit is derived from m-xylylenediamine, and 100 to 0 mol% (preferably 10). ~ 90 mol%) is derived from paraxylylenediamine, and 70 mol% or more (preferably 80 mol% or more, more preferably 90 mol% or more) of the constituent units derived from dicarboxylic acid is sebacic acid and / or 1,12. -Preferably those derived from dodecanedioic acid.

The xylylene diamine-based polyamide resin used in the present embodiment is composed of a diamine-derived structural unit and a dicarboxylic acid-derived structural unit, but these structural units may be the main components and other structural units. Needless to say, it does not completely eliminate the above, and may contain constituent units derived from lactams such as ε-caprolactam and laurolactam, and aliphatic aminocarboxylic acids such as aminocaproic acid and aminoundecanoic acid. Here, the main component means that among the constituent units constituting the xylylenediamine-based polyamide resin, the total number of the constituent units derived from diamine and the constituent units derived from dicarboxylic acid is the largest among all the constituent units. In the present embodiment, the total of the diamine-derived constituent units and the dicarboxylic acid-derived constituent units in the xylylenediamine-based polyamide resin preferably occupies 90% or more of all the constituent units, and more preferably 95% or more. preferable.

The melting point of the xylylenediamine-based polyamide resin is preferably 150 to 350 ° C., more preferably 180 to 330 ° C., and even more preferably 200 to 300 ° C.
The melting point can be measured according to JIS K7121 and K7122 according to the differential scanning calorimetry.

The lower limit of the number average molecular weight (Mn) of the xylylenediamine-based polyamide resin is preferably 6,000 or more, more preferably 8,000 or more, still more preferably 10,000 or more. It is more preferably 15,000 or more, further preferably 20,000 or more, and even more preferably 22,000 or more. The upper limit of Mn is preferably 35,000 or less, more preferably 30,000 or less, further preferably 28,000 or less, and even more preferably 26,000 or less. Within such a range, heat resistance, elastic modulus, dimensional stability, and molding processability become better.

The content of the xylylenediamine-based polyamide resin in the resin composition of the present embodiment is preferably 28% by mass or more, more preferably 30% by mass or more, and further preferably 32% by mass or more. , 38% by mass or more, more preferably 40% by mass or more. By setting the value to the lower limit or more, it is possible to maintain high mechanical properties while exhibiting excellent fluidity.
The content of the xylylenediamine-based polyamide resin in the resin composition of the present embodiment is preferably 60% by mass or less, more preferably 56% by mass or less, and preferably 53% by mass or less. Even more preferably, it is more preferably less than 50% by mass, and even more preferably 47% by mass or less. By setting the value to the upper limit or less, the mechanical strength of the molded product tends to be further improved.
The resin composition of the present embodiment may contain only one kind of xylylenediamine-based polyamide resin, or may contain two or more kinds. When two or more kinds are contained, it is preferable that the total amount is within the above range.

<Inorganic fiber>
The resin composition of the present embodiment contains 80 to 150 parts by mass of inorganic fibers with respect to 100 parts by mass of the xylylenediamine-based polyamide resin. By containing the inorganic fiber, the mechanical strength of the obtained molded product can be increased.
The type of inorganic fiber is not particularly specified, but carbon fiber and glass fiber are exemplified, and it is preferable to include glass fiber.

The inorganic fiber in the present embodiment means a fibrous inorganic material, and more specifically, a chopped shape in which 1,000 to 10,000 inorganic fibers are focused and cut to a predetermined length. Those are preferable.
The inorganic fiber in the present embodiment preferably has a number average fiber length of 0.5 to 10 mm, and more preferably 1 to 5 mm. By using such an inorganic fiber having a number average fiber length, the mechanical strength can be further improved. The number average fiber length is obtained by randomly extracting the inorganic fiber to be measured for the fiber length from the image obtained by observation with an optical microscope, measuring the long side thereof, and calculating the number average fiber length from the obtained measurement value. calculate. The observation magnification is 20 times, and the number of measurements is 1,000 or more. It roughly corresponds to the cut length.
The cross section of the inorganic fiber may be circular, oval, oval, rectangular, a shape in which both short sides of a rectangle are combined with a semicircle, an eyebrows shape, or the like, but a circular shape is preferable. The term "circle" here is intended to include, in addition to a circle in the mathematical sense, what is usually referred to as a circle in the technical field of the present embodiment. The same applies to the elliptical shape and the like.
In the present embodiment, the cross section of the inorganic fiber is preferably flat. By using the inorganic fiber having a flat cross section, the warp of the obtained molded product can be effectively suppressed. Further, the cross-sectional aspect ratio of the inorganic fiber is preferably 2 or more, and more preferably 2 to 6.
The lower limit of the number average fiber diameter of the inorganic fibers is preferably 4.0 μm or more, more preferably 4.5 μm or more, and further preferably 5.0 μm or more. The upper limit of the number average fiber diameter of the inorganic fibers is preferably 15.0 μm or less, and more preferably 12.0 μm or less. The number average fiber diameter of the inorganic fiber is obtained by randomly extracting the glass fiber to be measured for the fiber diameter from the image obtained by observation with an electron microscope and measuring the fiber diameter near the center. Calculated from the measured values. The observation magnification is 1,000 times, and the number of measurements is 1,000 or more. The number average fiber diameter of the glass fiber having a cross section other than the circular shape shall be the number average fiber diameter when converted into a circle having the same area as the area of the cross section.

Next, the glass fiber preferably used in this embodiment will be described.
As the glass fiber, in addition to the generally supplied E glass, a fiber obtained by melt-spinning glass such as C glass, A glass, S glass, D glass, M glass, R glass, and alkali resistant glass is used. However, it can be used as long as it can be made of glass fiber, and is not particularly limited. In this embodiment, it is preferable to include E glass.

The glass fiber used in this embodiment is surfaced with a surface treatment agent such as a silane coupling agent such as γ-methacryloxypropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, and γ-aminopropyltriethoxysilane. It is preferably treated. The amount of the surface treatment agent adhered is preferably 0.01 to 1% by mass of the glass fiber. Further, if necessary, a fatty acid amide compound, a lubricant such as silicone oil, an antistatic agent such as a quaternary ammonium salt, a resin having a film-forming ability such as an epoxy resin and a urethane resin, and a resin having a film-forming ability and heat. It is also possible to use a surface-treated mixture of a stabilizer, a flame retardant and the like.

Glass fiber is available as a commercial product. Examples of commercially available products include Nippon Electric Glass, T-286H, T-756H, T-289H, T-275H, T-296, Owens Corning, DEFT2A, PPG, HP3540, and Nitto Boseki. , CSG3PA-820, CSG3PA-810S and the like.

The content of the inorganic fiber in the resin composition of the present embodiment is 80 parts by mass or more, preferably 90 parts by mass or more, and preferably 100 parts by mass or more with respect to 100 parts by mass of the xylylenediamine-based polyamide resin. It is more preferably 105 parts by mass or more, further preferably 110 parts by mass or more, and further preferably 115 parts by mass or more. By setting the value to the lower limit or more, the mechanical strength of the molded product tends to be further improved.
The content of the inorganic fiber in the resin composition of the present embodiment is 150 parts by mass or less, preferably 145 parts by mass or less, and 140 parts by mass or less with respect to 100 parts by mass of the xylylenediamine-based polyamide resin. It is more preferably 135 parts by mass or less, further preferably 133 parts by mass or less, and even more preferably 131 parts by mass or less. By setting the value to the upper limit or less, the surface exposure of the inorganic fiber is suppressed and the appearance of the molded product tends to be further improved.

The content of the inorganic fiber (preferably glass fiber) in the present embodiment is also preferably 40% by mass or more, more preferably 44% by mass or more, still more preferably 47% by mass or more. , 50% by mass or more, more preferably 53% by mass or more. By setting the value to the lower limit or more, the mechanical strength of the molded product tends to be further improved. The content of the inorganic fiber in the resin composition of the present embodiment is preferably 72% by mass or less, more preferably 70% by mass or less, further preferably 68% by mass or less, 62. It is more preferably mass% or less, and even more preferably 60 mass% or less. By setting the value to the upper limit or less, the surface exposure of the inorganic fiber is suppressed and the appearance of the molded product tends to be further improved.
The resin composition of the present embodiment may contain only one kind of inorganic fiber, or may contain two or more kinds of inorganic fibers. When two or more kinds are contained, it is preferable that the total amount is within the above range.

<Inorganic crystal nucleating agent>
The resin composition of the present embodiment contains 0.1 to 10 parts by mass of an inorganic crystal nucleating agent with respect to 100 parts by mass of a xylylenediamine-based polyamide resin. By containing the inorganic crystal nucleating agent, crystallization can be promoted and the mechanical properties of the polyamide can be maximized.
The inorganic crystal nucleating agent is not particularly limited as long as it is unmelted at the time of melt processing and can become a crystal nuclei in the cooling process.
Examples of the inorganic crystal nucleating agent include graphite, molybdenum disulfide, barium sulfate, talc, mica, calcium carbonate, sodium phosphate, boron nitride, and kaolin, and are selected from talc, mica, calcium carbonate, and boron nitride. It is preferable to contain one or more kinds thereof, more preferably one or more kinds selected from talc and calcium carbonate, and further preferably containing talc.
The lower limit of the number average particle size of the inorganic crystal nucleating agent is preferably 0.1 μm or more, and more preferably 1 μm or more. The upper limit of the number average particle size of the inorganic crystal nucleating agent is preferably 40 μm or less, more preferably 30 μm or less, further preferably 28 μm or less, still more preferably 15 μm or less. It is even more preferably 10 μm or less. By setting the number average particle diameter to 40 μm or less, the number of the inorganic crystal nucleating agents as nuclei increases as compared with the blending amount of the inorganic crystal nucleating agents, so that the crystal structure tends to be more stable.

The content of the inorganic crystal nucleating agent in the resin composition of the present embodiment is 0.1 part by mass or more, preferably 0.2 part by mass or more, based on 100 parts by mass of the xylylenediamine-based polyamide resin. It may be 0.5 parts by mass or more, and further may be 0.8 parts by mass or more. By setting the value to the lower limit or more, the crystalline state of the resin composition can be more sufficiently stabilized. The content of the inorganic crystal nucleating agent in the resin composition of the present embodiment is 10 parts by mass or less, preferably 8 parts by mass or less, preferably 6 parts by mass, based on 100 parts by mass of the xylylenediamine-based polyamide resin. It is more preferably parts or less, more preferably 5 parts by mass or less, and may be 4 parts by mass or less. By setting the value to the upper limit or less, it becomes possible to further improve the mechanical strength of the molded product molded by using the resin composition.

The content of the inorganic crystal nucleating agent in the resin composition of the present embodiment is preferably 0.1% by mass or more in the resin composition, and the content of the inorganic crystal nucleating agent in the resin composition of the present embodiment is contained. The amount is preferably 4.5% by mass or less, more preferably 3.0% by mass or less, and further preferably 2.5% by mass or less in the resin composition.
The resin composition of the present embodiment may contain only one kind of inorganic crystal nucleating agent, or may contain two or more kinds of inorganic crystal nucleating agents. When two or more kinds are contained, it is preferable that the total amount is within the above range.

<Fatty acid metal salt>
The resin composition of the present embodiment contains 0.01 to 2 parts by mass of a fatty acid metal salt with respect to 100 parts by mass of a xylylenediamine-based polyamide resin. The fatty acid metal salt functions as a mold release agent and improves the mold release property. Further, a fatty acid amide wax or the like is also known as a mold release agent, but in the present embodiment, a fatty acid metal salt is used from the viewpoint of more effectively exhibiting the performance as a lubricant.
As the fatty acid constituting the fatty acid metal salt, a fatty acid having 20 or more carbon chains is preferable, a fatty acid having 20 to 35 carbon chains is more preferable, and a fatty acid having 25 to 30 carbon chains is further preferable. Specific examples of the fatty acid constituting the fatty acid metal salt include stearic acid, 12-hydroxystearic acid, behenic acid, montanic acid, and ricinoleic acid, and montanic acid is preferable.
Examples of the metal constituting the fatty acid metal salt include calcium, magnesium, zinc, aluminum, barium, and lithium, and calcium is preferable.

The content of the fatty acid metal salt in the resin composition of the present embodiment is 0.01 part by mass or more, preferably 0.05 part by mass or more, preferably 0 parts by mass, based on 100 parts by mass of the xylylenediamine-based polyamide resin. .1 part by mass or more is further preferable, 0.3 part by mass or more is further preferable, and 0.5 part by mass or more is further preferable. By setting the value to the lower limit or more, the mold release resistance at the time of mold release can be lowered, and the protrusion deformation of the molded product can be effectively suppressed. The content of the fatty acid metal salt in the resin composition of the present embodiment is preferably 2 parts by mass or less and preferably 1.7 parts by mass or less with respect to 100 parts by mass of the xylylenediamine-based polyamide resin. It is more preferably 4 parts by mass or less, further preferably 1.1 parts by mass or less, and further preferably 0.9 parts by mass or less. By setting the value to the upper limit or less, bleed-out of the fatty acid metal salt and gas during molding can be effectively suppressed.
The resin composition of the present embodiment may contain only one type of fatty acid metal salt, or may contain two or more types. When two or more kinds are contained, it is preferable that the total amount is within the above range.

<Other additives>
The resin composition of the present embodiment may contain other components in addition to the above. Other components include thermoplastic resins other than xylylene diamine-based polyamide resins, light stabilizers, heat stabilizers, mold release agents other than fatty acid metal salts, alkalis, elastomers, titanium oxide, antioxidants, and hydrolysis resistance. Examples thereof include improvers, matting agents, ultraviolet absorbers, organic crystal nucleating agents, plasticizers, dispersants, antistatic agents, anticoloring agents, antigelling agents, flame retardants, and coloring agents. These details can be referred to in paragraphs 0130 to 0155 of Japanese Patent No. 4894982, and these contents are incorporated in the present specification. The total amount of these components is preferably 20% by mass or less, more preferably 10% by mass or less, and further preferably 5% by mass or less. As each of these components, only one kind may be used, or two or more kinds may be used in combination.
In the resin composition of the present embodiment, the total of the xylylenediamine-based polyamide resin, the inorganic fiber, the fatty acid metal salt and the inorganic crystal nucleating agent preferably occupies 95% by mass or more, and occupies 99% by mass or more of the resin composition. More preferably, it may be 100% by mass.

<< Other resins >>
The resin composition of the present embodiment may or may not contain a polyamide resin other than the xylylenediamine-based polyamide resin and a resin other than the polyamide resin.
The polyamide resin other than the xylylenediamine-based polyamide resin may be an aliphatic polyamide resin or a semi-aromatic polyamide resin. Examples of the aliphatic polyamide resin include polyamide 6, polyamide 11, polyamide 12, polyamide 46, polyamide 66, polyamide 610, and polyamide 612. Examples of the semi-aromatic polyamide resin include polyamide 6T, polyamide 6I / 6T, and polyamide 9T.
Examples of the resin other than the polyamide resin include elastomers, vinyl resins, styrene resins, acrylic resins, polyester resins, polycarbonate resins, polyacetal resins and the like.
Further, the resin composition of the present embodiment preferably has a structure that does not substantially contain other resin components other than the xylylenediamine-based polyamide resin. The term "substantially free" means that the content of other resin components is 10% by mass or less of the content of the xylylenediamine-based polyamide resin, preferably 5% by mass or less, and 3% by mass. It is more preferably 1% by mass or less, further preferably 0.5% by mass or less, 0.1% by mass or less, and further preferably 0% by mass.

In the resin composition of the present embodiment, the content of the release agent other than the fatty acid metal salt is preferably 10% by mass or less, more preferably 5% by mass or less, and 3% by mass of the content of the fatty acid metal salt. It is more preferably% or less, and even more preferably 1% by mass or less.

<Physical characteristics of resin composition>
The resin composition of the present embodiment preferably has a low water absorption rate. Specifically, the mass increase rate when the resin composition is molded into a 1.0 mm thick molded product, dried at 80 ° C. for 48 hours, and then immersed in water at 23 ° C. for 24 hours is 0.45% or less. It is more preferably 0.35% or less, further preferably 0.25% or less, and even more preferably 0.20% or less. The lower limit of the mass increase rate is ideally 0%, but 0.01% or more is practical, and even if it is 0.10% or more, the required performance is sufficiently satisfied.

In the resin composition of the present embodiment, when the resin composition is molded into a molded product having a thickness of 1 mm at a mold temperature of 100 ° C., the calorific value of the crystallization peak in the differential scanning calorimetry is 1 J / g or less. It is preferable that there is or no crystallization peak is observed. A resin composition satisfying such performance is sufficiently crystallized even in low mold temperature molding when it is made into a molded product, and a molded product having an excellent appearance can be obtained.

The resin composition of the present embodiment preferably has a bending strength of 290 MPa or more, more preferably 300 MPa or more, and even more preferably 310 MPa or more, when molded to a thickness of 4 mm. .. The upper limit of the bending strength is not particularly determined, but is practically 400 MPa or less, for example.
The resin composition of the present embodiment preferably has a flexural modulus of 15.0 GPa or more, more preferably 17.0 GPa or more, and 18.0 GPa or more when molded to a thickness of 4 mm. Is more preferable. The upper limit of the flexural modulus is not particularly defined, but is practically, for example, 30.0 GPa or less, further 25.0 GPa or less.

The resin composition of the present embodiment preferably has a notched Charpy impact strength of 10 kJ / m ² or more when molded to a thickness of 4 mm and conforms to the ISO179 standard. The upper limit of the Charpy impact strength with a notch is not particularly determined, but is practically, for example, 30 kJ / m ² or less, and further 25 kJ / m ² or less.
The resin composition of the present embodiment preferably has a notched Charpy impact strength of 40 kJ / m ² or more, and more preferably 45 kJ / m ² or more, when molded to a thickness of 4 mm. It is preferably 50 kJ / m ² or more, and more preferably 50 kJ / m 2. The upper limit of the Charpy impact strength with a notch is not particularly defined, but is practically, for example, 120 kJ / m ² or less, and further 100 kJ / m ² or less.
The mass increase rate, crystallization peak, bending strength, flexural modulus and Charpy impact strength are measured by the methods described in Examples described later.

<Manufacturing method of resin composition>
Any method is adopted as the method for producing the resin composition of the present embodiment.
For example, a xylylenediamine-based polyamide resin, an inorganic fiber, a fatty acid metal salt and an inorganic crystal nucleating agent, and other components to be blended as necessary are mixed by a mixing means such as a V-type blender to prepare a batch blend product. After preparation, a method of melt-kneading with an extruder with a vent to pelletize can be mentioned. Alternatively, as a two-step kneading method, components other than inorganic fibers are sufficiently mixed in advance, melt-kneaded with an extruder with a vent to produce pellets, and the pellets and a reinforced filler are mixed and then vented. A method of melt-kneading with an extruder can be mentioned.
Further, a component other than the inorganic fiber is sufficiently mixed with a V-type blender or the like, and the mixture is prepared in advance and supplied from the first chute of the twin-screw extruder with a vent. Examples thereof include a method of supplying from two shoots, melt-kneading, and pelletizing.

The heating temperature for melt-kneading can be appropriately selected from the range of usually 180 to 360 ° C. If the temperature is too high, decomposition gas is likely to be generated, which may cause extrusion defects such as broken strands. Therefore, it is desirable to select a screw configuration in consideration of shear heat generation and the like. It is desirable to use an antioxidant or a heat stabilizer in order to suppress decomposition during kneading and molding in the subsequent process.

<Molded product>
The present embodiment also relates to a molded product molded from the resin composition of the present embodiment. The molded product in this embodiment is preferably a thin-walled molded product. The thin-walled molded product refers to, for example, a molded product having a thinnest portion of 1.0 mm or less (preferably 0.1 mm or more, preferably 0.6 mm or less).

The method for producing a molded product in the present embodiment is not particularly limited, and a molding method generally adopted for a resin composition can be arbitrarily adopted. For example, an injection molding method, an ultra-high speed injection molding method, an injection compression molding method, a two-color molding method, a hollow molding method such as gas assist, a molding method using a heat insulating mold, and a rapid heating mold were used. Molding method, foam molding (including supercritical fluid), insert molding, IMC (in-mold coating molding) molding method, extrusion molding method, sheet molding method, thermal molding method, rotary molding method, laminated molding method, press molding method, Blow molding method and the like can be mentioned. Further, a molding method using a hot runner method can also be used.
In the present embodiment, it is preferable to include injection molding of the resin composition in the production of a molded product (preferably a thin-walled molded product). Further, in the case of injection molding, the cylinder temperature can be 220 to 330 ° C. and the mold temperature can be 80 to 140 ° C. By using the resin composition of the present embodiment, a molded product having an excellent appearance can be obtained even if the mold temperature is low.

The molded product of this embodiment has good mechanical strength, low water absorption, and is also excellent in use as a thin-walled molded product. Therefore, various uses such as various storage containers, electrical / electronic equipment parts, and office autos are used. It can be applied to mate (OA) equipment parts, home appliance equipment parts, mechanical mechanism parts, vehicle mechanism parts, and the like. In particular, food containers, chemical containers, oil and fat product containers, vehicle hollow parts (various tanks, intake manifold parts, camera housings, etc.), vehicle electrical components (various control units, ignition coil parts, etc.), motor parts, etc. It can be suitably used for various sensor parts, connector parts, switch parts, breaker parts, relay parts, coil parts, transformer parts, lamp parts and the like. In particular, the resin composition of the present embodiment is excellent for mobile phones, smartphones and the like.

Hereinafter, the present invention will be described in more detail with reference to examples. The materials, amounts used, ratios, treatment contents, treatment procedures, etc. shown in the following examples can be appropriately changed as long as they do not deviate from the gist of the present invention. Therefore, the scope of the present invention is not limited to the specific examples shown below.
If the measuring device or the like used in the examples is difficult to obtain due to a discontinued number or the like, measurement can be performed using another device having the same performance.

1. 1. Raw material <polyamide resin>
MP10: M / P molar ratio = 7: 3, and the composition was performed according to the following synthesis example.
<< Synthesis example of MP10 (M / P molar ratio = 7: 3) >>
After heat-dissolving sebacic acid in a reaction can under a nitrogen atmosphere, the molar ratio of metaxylylenediamine (manufactured by Mitsubishi Gas Chemical Company) and paraxylylenediamine (manufactured by Mitsubishi Gas Chemical Company) is adjusted while stirring the contents. The temperature was raised to 235 ° C. by gradually dropping the 7: 3 mixed diamine under pressure (0.35 MPa) so that the molar ratio of diamine to sebacic acid was about 1: 1. After completion of the dropping, the reaction was continued for 60 minutes to adjust the amount of components having a molecular weight of 1,000 or less. After completion of the reaction, the contents were taken out into strands and pelletized with a pelletizer to obtain a polyamide resin (MP10). The melting point of the obtained polyamide was 215 ° C.

MP12: M / P molar ratio = 6: 4, synthesis was performed according to the following synthesis example.
<< Example of MP12 synthesis >>
In a reaction vessel equipped with a stirrer, a splitter, a total crimp, a thermometer, a dropping funnel and a nitrogen introduction tube, and a strand die, weighed 13,820 g (60 mol) of dodecane diic acid and one water of sodium hypophosphite. Add 10.180 g of Japanese product (NaH ₂ PO ₂ · H ₂ O) (150 mass ppm of phosphorus atom in polyamide resin) and 5.25 g of sodium acetate, sufficiently replace with nitrogen, and then under a small amount of nitrogen stream. The inside of the system was heated to 170 ° C. with stirring. The molar ratio of sodium acetate / sodium hypophosphate monohydrate was 0.67.
To this, 8,173 g (60 mol) of a 6: 4 mixed diamine of m-xylylenediamine and para-xylylenediamine was added dropwise under stirring, and the temperature inside the system was continuously raised while removing the generated condensed water into the system. .. After the completion of the dropping of the mixed metaxylylenediamine, the melt polymerization reaction was continued for 40 minutes at an internal temperature of 260 ° C.
Then, the inside of the system was pressurized with nitrogen, and the polymer was taken out from the strand die and pelletized. The melting point of the obtained polyamide was 216 ° C.

MP6: M / P molar ratio = 7: 3, and the composition was performed according to the following synthesis example.
<< Example of MP6 synthesis (M / P molar ratio = 7: 3) >>
After heat-dissolving adipic acid in a reaction can under a nitrogen atmosphere, the molar ratio of metaxylylenediamine (manufactured by Mitsubishi Gas Chemical Company) and paraxylylenediamine (manufactured by Mitsubishi Gas Chemical Company) is adjusted while stirring the contents. The temperature of the 7: 3 mixed diamine was gradually dropped to 270 ° C. under pressure (0.35 MPa) so that the molar ratio of diamine to adipic acid (manufactured by Rhodia) was about 1: 1. Raised. After completion of the dropping, the pressure was reduced to 0.06 MPa and the reaction was continued for 10 minutes to adjust the molecular weight of the components having a molecular weight of 1,000 or less. Then, the contents were taken out in a strand shape and pelletized with a pelletizer to obtain a polyamide resin (MP6). The melting point of the obtained polyamide was 256 ° C.

PA6: Nylon 6, manufactured by Ube Kosan Co., Ltd., 1011FB, melting point 225 ° C.

<Inorganic fiber>
CSG3PA-810S: Nitto Boseki Co., Ltd., chopped glass fiber with flat cross section, E glass, cross section aspect ratio 4
T-296GH: Nippon Electric Glass Co., Ltd., chopped glass fiber with round (circular) cross section, E glass, number average fiber diameter 10 μm, cross section aspect ratio 1

<Inorganic crystal nucleating agent>
5000S: MW (micron white) 5000S, talc, manufactured by Hayashi Kasei Co., Ltd., number average particle diameter 5 μm

<Fatty acid metal salt>
CS8CP: Nitto Kasei Kogyo Co., Ltd., calcium montanate <release agent (for comparison)>
WH255: Kyoeisha Chemical Co., Ltd., fatty acid amid wax, melting point 255 ° C.

2. 2. Examples 1 to 6, Comparative Examples 1 to 5
<Compound>
Each component is weighed so as to have the composition shown in Tables 1 to 3 described later, the components excluding the inorganic fiber are blended with a tumbler, and the components are charged from the root of a twin-screw extruder (manufactured by Toshiba Machine Co., Ltd., TEM26SS). After melting, the inorganic fibers were side-fed to prepare pellets. The temperature of the twin-screw extruder was set to 280 ° C. Each component in Tables 1 to 3 is shown by mass ratio.

<Flexural strength and flexural modulus>
After the pellets obtained by the above manufacturing method are dried at 120 ° C. for 4 hours, the cylinder temperature is 300 ° C., the mold temperature is 130 ° C., and the molding cycle is carried out by an injection molding machine (“NEX140III” manufactured by Nissei Resin Industry Co., Ltd.). An ISO multipurpose dumbbell test piece (4 mm thick) was injection molded under the condition of 50 seconds.
Bending strength (unit: MPa) and flexural modulus (unit: GPa) were measured at a temperature of 23 ° C. according to ISO178.

<Deflection temperature under load (DTUL)>
After the pellets obtained by the above method are dried at 120 ° C. for 4 hours, the cylinder temperature is 280 ° C., the mold temperature is 130 ° C., and the molding cycle is 50 in an injection molding machine (“NEX140III” manufactured by Nissei Resin Industry Co., Ltd.). An ISO multipurpose dumbbell test piece (4 mm thick) was injection molded under the condition of seconds.
According to ISO75-1 and ISO75-2, the deflection temperature under load (unit: ° C.) was measured under a load (1.80 MPa) for the ISO multipurpose test piece.

<Charpy impact strength>
After the pellets obtained by the above manufacturing method are dried at 120 ° C. for 4 hours, the cylinder temperature is 280 ° C., the mold temperature is 130 ° C., and the molding cycle is carried out by an injection molding machine (“NEX140III” manufactured by Nissei Resin Industry Co., Ltd.). An ISO multipurpose dumbbell test piece (4 mm thick) was injection molded under the condition of 50 seconds.
Charpy impact strength (with and without notches) was measured at a temperature of 23 ° C. according to ISO179 standards.
The unit is kJ / m ² .

<Spiral flow length>
After the pellets obtained by the above manufacturing method are dried at 120 ° C. for 4 hours, a spiral flow mold (thickness 1 mm, width 5 mm) is used in an injection molding machine (“EC50SX” manufactured by Toshiba Machine Co., Ltd.). Then, molding was performed under the conditions of a cylinder temperature of 280 ° C. and a mold temperature of 130 ° C., and the flow length when molded at an injection pressure of 100 MPa was measured.
The unit is shown in cm.

<Mass increase rate>
After the pellets obtained by the above manufacturing method are dried at 120 ° C. for 4 hours, the cylinder temperature is 280 ° C., the mold temperature is 130 ° C., and the molding cycle is carried out by an injection molding machine (“NEX140III” manufactured by Nissei Resin Industry Co., Ltd.). Under the condition of 50 seconds, a flat plate test piece having a size of 60 mm × 60 mm × thickness 1 mm was injection-molded.
The test piece obtained above was dried at 80 ° C. for 48 hours, then returned to room temperature in an aluminum moisture-proof bag, immersed in water at 23 ° C. for 24 hours, and the mass increase rate was measured. The mass increase rate was measured based on the following formula.
Mass increase rate (unit:%)
= [(Mass after immersion)-(Mass before immersion)] / (Mass before immersion) x 100

<DSC (Differential Scanning Calorimetry) Low Temperature Crystallization Peak>
After the pellets obtained by the above manufacturing method are dried at 120 ° C. for 4 hours, the cylinder temperature is 280 ° C., the mold temperature is 100 ° C., and the molding cycle is carried out by an injection molding machine (“NEX140III” manufactured by Nissei Resin Industry Co., Ltd.). Under the condition of 50 seconds, a flat plate test piece having a size of 60 mm × 60 mm × thickness 1 mm was injection-molded, and the low-temperature crystallization peak of the flat plate test piece was measured by DSC (differential scanning calorimetry). Specifically, a 10 mg sample was cut out from a flat plate test piece, and the obtained sample was heated to 30 to 300 ° C. at a rate of 10 ° C./min using a DSC-7200 manufactured by Hitachi High-Tech Science Co., Ltd., and 70. The exothermic peak appearing at ~ 110 ° C. was detected as a low temperature crystallization peak.
When the peak calorific value is detected at 1 J / g or more, crystallization is insufficient, and it can be said that the finished product is insufficient. N. D. means that no clear crystallization peak was detected.

As is clear from the above results, the molded product formed from the resin composition of the present invention has a long spiral flow length while maintaining high mechanical strength, is sufficiently crystallized even in low temperature molding, and has a mass after immersion in water. The rate of increase could be effectively suppressed.
On the other hand, when a mold release agent other than the fatty acid metal salt was used, the spiral flow length became smaller (Comparative Example 1).
Further, when the inorganic crystal nucleating agent was not blended (Comparative Example 2), crystallization was insufficient by low temperature molding.
Further, when a polyamide resin formed from an aliphatic dicarboxylic acid (adipic acid) having 6 carbon atoms and xylylenediamine is used (Comparative Example 3), the spiral flow length is short and crystals are formed in low temperature molding. The conversion was insufficient.
Further, when nylon 6 was used as the polyamide resin (Comparative Example 4), the spiral flow length was long and the crystals were sufficiently crystallized even by low-temperature molding, but the mass increase after immersion in water was large.
On the other hand, when the blending amount of the inorganic crystal nucleating agent was large (Comparative Example 5), the spiral flow length became short.

Claims (12)

It is composed of a diamine-derived structural unit and a dicarboxylic acid-derived structural unit. 70 mol% or more of the diamine-derived structural unit is derived from xylylene diamine, and 70 mol% or more of the dicarboxylic acid-derived structural unit has 9 to 9 carbon atoms. 80 to 150 parts by mass of inorganic fiber, 0.01 to 2 parts by mass of fatty acid metal salt, and 0.1 to 10 parts by mass of inorganic crystal nucleating agent with respect to 100 parts by mass of a polyamide resin derived from 18 aliphatic dicarboxylic acids. Including, resin composition. The claim that the mass increase rate when the resin composition is molded into a molded product having a thickness of 1.0 mm, dried at 80 ° C. for 48 hours, and then immersed in water at 23 ° C. for 24 hours has a mass increase rate of 0.45% or less. The resin composition according to 1. The resin composition according to claim 1 or 2, wherein the inorganic fiber has a cross-sectional aspect ratio of 2 or more. The resin composition according to any one of claims 1 to 3, wherein the inorganic crystal nucleating agent contains at least one selected from talc, mica, calcium carbonate, and boron nitride. The resin composition according to any one of claims 1 to 4, wherein the fatty acid metal salt is a fatty acid metal salt having 20 or more carbon chains. The content of the polyamide resin is 40% by mass or more and less than 50% by mass, the content of the inorganic fiber is 50 to 60% by mass, and the content of the inorganic crystal nucleating agent is 0.1 to The resin composition according to any one of claims 1 to 5, which is 4.5% by mass. When the resin composition is molded into a molded product having a thickness of 1 mm at a mold temperature of 100 ° C., the crystallization peak is observed whether the calorific value of the crystallization peak in the differential scanning calorimetry is 1 J / g or less. The resin composition according to any one of claims 1 to 6, which is not contained. The total amount of m-xylylenediamine of 10 to 90 mol% and paraxylylenediamine of 90 to 10 mol% (however, the total of methylylenediamine and paraxylylenediamine does not exceed 100 mol%). ), The resin composition according to any one of claims 1 to 7. The resin composition according to any one of claims 1 to 8, wherein the dicarboxylic acid contains sebacic acid and / or 1,12-dodecanedic acid. The resin composition according to any one of claims 1 to 8, wherein the dicarboxylic acid contains 1,12-dodecane diic acid. A molded product formed from the resin composition according to any one of claims 1 to 10. A method for producing a thin-walled molded product, which comprises injection molding the resin composition according to any one of claims 1 to 10.