JP7705742B2 - Fiber-reinforced resin material, molded product, and method for producing fiber-reinforced resin material - Google Patents

Description

The present invention relates to a fiber-reinforced resin material, a molded product, and a method for producing a fiber-reinforced resin material.

2. Description of the Related Art Conventionally, in order to improve the mechanical strength of molded articles formed from thermoplastic resins, fiber-reinforced resin materials in which reinforcing fibers are blended with thermoplastic resins have been investigated.
In particular, fiber-reinforced resin materials using long fibers have been studied to increase the mechanical strength of molded products (Patent Document 1, Patent Document 2). In addition, Patent Document 2 describes how, in producing such a fiber-reinforced resin material, glass fiber rovings are introduced into a crosshead of an impregnation die filled with a molten polyamide resin composition to obtain a resin-impregnated glass fiber roving bundle. Furthermore, the obtained resin-impregnated glass fiber roving bundle is continuously taken up from a spinneret to obtain a single strand. Furthermore, this strand is cooled and solidified in a water-cooled bath, and the strand is pelletized by a pelletizer.

JP 2018-168287 A JP 2017-082028 A

However, as described above, when the thermoplastic resin is impregnated into long fibers such as glass fiber rovings, the thermoplastic resin may thicken and break the long fibers.
The present invention aims to solve such problems, and to provide a fiber-reinforced resin material that can be efficiently produced and in which the long fibers are less likely to break when the thermoplastic resin is impregnated into the long fibers, as well as a molded product using the fiber-reinforced resin material, and a method for producing the fiber-reinforced resin material.

In view of the above problems, the present inventors have conducted research and found that the above problems can be solved by blending a prescribed amount of a metal acetate in a thermoplastic resin component.
Specifically, the above problems were solved by the following means.
<1> A fiber-reinforced resin material comprising 65 to 170 parts by mass of inorganic fibers having a number average fiber length of 3 mm or more per 100 parts by mass of a thermoplastic resin component, and 0.05 to 0.50 parts by mass of at least one metal acetate salt per 100 parts by mass of the thermoplastic resin component.
<2> The fiber-reinforced resin material according to <1>, wherein the metal acetate salt includes at least one selected from sodium acetate, calcium acetate, and magnesium acetate.
<3> The fiber-reinforced resin material according to <1> or <2>, wherein the inorganic fibers include glass fibers and/or carbon fibers.
<4> The fiber-reinforced resin material according to <1> or <2>, wherein the inorganic fibers include glass fibers.
<5> The fiber reinforced resin material according to any one of <1> to <4>, wherein the thermoplastic resin component contains a polyamide resin.
<6> The polyamide resin contains a diamine-derived structural unit and a dicarboxylic acid-derived structural unit, and 70 mol% or more of the diamine-derived structural units are derived from xylylenediamine, and 70 mol% or more of the dicarboxylic acid-derived structural units are derived from an α,ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms. The fiber-reinforced resin material according to <5>.
<7> The fiber-reinforced resin material according to any one of <1> to <6>, wherein the inorganic fibers have a number average fiber length of 10 mm or less.
<8> The fiber-reinforced resin material according to any one of <1> to <6>, wherein the inorganic fibers have a number average fiber length of 2 cm or more.
<9> The fiber reinforced resin material according to any one of <1> to <7>, wherein the fiber reinforced resin material is in the form of pellets.
<10> The fiber reinforced resin material according to any one of <1> to <6> and <8>, wherein the fiber reinforced resin material is a UD tape (unidirectional tape).
<11> A molded product formed from the fiber-reinforced resin material according to any one of <1> to <10>.
<12> A method for producing a fiber-reinforced resin material, comprising impregnating 100 parts by mass of a thermoplastic resin component containing 0.05 to 0.50 parts by mass of at least one metal acetate salt per 100 parts by mass of a thermoplastic resin component with 65 to 170 parts by mass of inorganic fibers having a number average fiber length of 2 cm or more.
<13> The method for producing the fiber-reinforced resin material according to <12>, comprising forming the metal acetate into a masterbatch with a thermoplastic resin and then blending it with other components to obtain the thermoplastic resin component.
<14> The method for producing a fiber-reinforced resin material according to <13>, wherein the blend is a dry blend.
<15> The fiber reinforced resin material according to any one of <12> to <14>, wherein the fiber reinforced resin material is the fiber reinforced resin material according to any one of <1> to <10>.

The present invention makes it possible to provide a fiber-reinforced resin material that is less likely to break when the long fibers are impregnated with a thermoplastic resin and can be produced efficiently, as well as a molded product that uses the fiber-reinforced resin material and a method for producing the fiber-reinforced resin material.

Hereinafter, an embodiment of the present invention (hereinafter, simply referred to as the present embodiment) will be described in detail. Note that the present embodiment is an example for explaining the present invention, and the present invention is not limited to the present embodiment.
In this specification, the word "to" is used to mean that the numerical values before and after it are included as the lower limit and upper limit.
In this specification, various physical properties and characteristic values are those at 23° C. unless otherwise specified.
In cases where the standards shown in this specification differ depending on the year and the measurement methods, etc., they will be based on the standards as of January 1, 2021, unless otherwise specified.

The fiber-reinforced resin material of the present embodiment is characterized in that it contains 65 to 170 parts by mass of inorganic fibers having a number average fiber length of 3 mm or more per 100 parts by mass of a thermoplastic resin component, and contains 0.05 to 0.50 parts by mass of at least one type of metal acetate salt per 100 parts by mass of the thermoplastic resin component. By using such a configuration, breakage of the long fibers can be effectively suppressed in the manufacturing process of the fiber-reinforced material, and the fiber-reinforced resin material can be efficiently obtained.
That is, by blending a metal acetate with a thermoplastic resin component, the increase in viscosity of the resin in the impregnation die can be suppressed, and the breakage of long fibers (e.g., glass fiber rovings) can be suppressed, thereby significantly improving productivity.
The reason for this is presumed to be the following. First, polymerization of thermoplastic resins tends to proceed under acidic conditions. In this embodiment, it is presumed that the increase in molecular weight was suppressed by blending metal acetate to create basic conditions. On the other hand, if the blending amount of metal acetate is too large, impregnation proceeds efficiently, but the ash content decreases due to an extreme decrease in viscosity, and the mechanical strength of molded products molded from the obtained fiber-reinforced resin material tends to be inferior. In this embodiment, it is presumed that the above problem was solved by adjusting the blending amount of metal acetate.

The fiber-reinforced resin material of this embodiment contains a thermoplastic resin component. The thermoplastic resin component contains a metal acetate salt in addition to a thermoplastic resin. It may further contain other resin additives.

The thermoplastic resin contained in the thermoplastic resin component is not particularly specified, and preferred examples include polyester resins such as polyethylene terephthalate resin, polytrimethylene terephthalate resin, and polybutylene terephthalate resin; polyamide resin; polycarbonate resin; styrene-based resin; polyolefin resins such as polyethylene resin, polypropylene resin, and cyclic cycloolefin resin; polyacetal resin; polyimide resin; polyetherimide resin; polyurethane resin; polyphenylene ether resin; polyphenylene sulfide resin; polysulfone resin; polymethacrylate resin; and the like. It is preferable that the thermoplastic resin contains at least one of polybutylene terephthalate resin, polyamide resin, polycarbonate resin, and polyacetal resin, and it is more preferable that the thermoplastic resin contains polyamide resin.

The thermoplastic resin in this embodiment is particularly suitable for a thermoplastic resin obtained by a polycondensation reaction, which is presumably because the polymerization reaction can be suppressed under basic conditions.
The thermoplastic resin in this embodiment is preferably a crystalline thermoplastic resin. The effect of stabilizing the production is more effectively exhibited in the crystalline thermoplastic resin. The crystalline thermoplastic resin is one that shows a clear exothermic peak when measured according to a differential scanning calorimeter.
In this embodiment, polyamide resin is particularly preferable because the impregnation of the long fibers with the polyamide resin is carried out at extremely high heating temperatures, during which the polyamide resin starts to decompose, the end group concentration increases, and the polyamide resin reacts with the surface treatment agent of the long fibers, etc., and tends to become more viscous.

The type of polyamide resin used in this embodiment is not particularly limited, and may be either 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, polyamide 612, and polyamide 6/66, with polyamide 66 being preferred.
The polyamide resin used in this embodiment preferably contains a semi-aromatic polyamide resin. For example, it is more preferable that 90% by mass or more of the polyamide resin contained in the thermoplastic resin component in this embodiment is a semi-aromatic polyamide resin. Here, the semi-aromatic polyamide resin is composed of a diamine-derived structural unit and a dicarboxylic acid-derived structural unit, and 20 to 80 mol% of the total structural units of the diamine-derived structural unit and the dicarboxylic acid-derived structural unit are structural units containing an aromatic ring. By using such a semi-aromatic polyamide resin, the mechanical strength of the obtained molded product can be increased. Examples of semi-aromatic polyamide resins include terephthalic acid-based polyamide resins (polyamide 6T, polyamide 9T, polyamide 10T) and xylylenediamine-based polyamide resins described later.

At least one of the polyamide resins used in the present embodiment contains diamine-derived structural units and dicarboxylic acid-derived structural units, and it is preferred that 70 mol % or more of the diamine-derived structural units are derived from xylylenediamine and 70 mol % or more of the dicarboxylic acid-derived structural units are derived from an α,ω-linear aliphatic dicarboxylic acid having a carbon number of 4 to 20. Hereinafter, such a polyamide resin may be referred to as a xylylenediamine-based polyamide resin.
The diamine-derived constituent units of the xylylenediamine-based polyamide resin are more preferably 75 mol % or more, even more preferably 80 mol % or more, still more preferably 85 mol % or more, even more preferably 90 mol % or more, and even more preferably 95 mol % or more derived from xylylenediamine. The dicarboxylic acid-derived constituent units of the xylylenediamine-based polyamide resin are more preferably 75 mol % or more, even more preferably 80 mol % or more, still more preferably 90 mol % or more, and even more preferably 95 mol % or more derived from an α,ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms.

Diamines other than meta-xylylenediamine and para-xylylenediamine that can be used as raw diamine components for xylylenediamine-based polyamide resins include aliphatic diamines such as tetramethylenediamine, pentamethylenediamine, 2-methylpentanediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, dodecamethylenediamine, 2,2,4-trimethyl-hexamethylenediamine, and 2,4,4-trimethylhexamethylenediamine, 1,3-bis( Examples of such diamines include alicyclic diamines such as bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, 1,3-diaminocyclohexane, 1,4-diaminocyclohexane, bis(4-aminocyclohexyl)methane, 2,2-bis(4-aminocyclohexyl)propane, bis(aminomethyl)decalin, and bis(aminomethyl)tricyclodecane; and diamines having an aromatic ring such as bis(4-aminophenyl)ether, paraphenylenediamine, and bis(aminomethyl)naphthalene. These can be used alone or in combination of two or more kinds.

Examples of α,ω-straight-chain aliphatic dicarboxylic acids having 4 to 20 carbon atoms that are suitable for use as the raw dicarboxylic acid component of xylylenediamine-based polyamide resins include aliphatic dicarboxylic acids such as succinic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, adipic acid, sebacic acid, undecanedioic acid, and dodecanedioic acid. One or more of these can be used in combination, but among these, adipic acid or sebacic acid are more preferred, and adipic acid is even more preferred, since the melting point of the polyamide resin falls within a range suitable for molding.

Examples of dicarboxylic acid components other than the α,ω-linear aliphatic dicarboxylic acids having 4 to 20 carbon atoms include phthalic acid compounds such as isophthalic acid, terephthalic acid, and orthophthalic acid, and isomers of naphthalene dicarboxylic acids such as 1,2-naphthalene dicarboxylic acid, 1,3-naphthalene dicarboxylic acid, 1,4-naphthalene dicarboxylic acid, 1,5-naphthalene dicarboxylic acid, 1,6-naphthalene dicarboxylic acid, 1,7-naphthalene dicarboxylic acid, 1,8-naphthalene dicarboxylic acid, 2,3-naphthalene dicarboxylic acid, 2,6-naphthalene dicarboxylic acid, and 2,7-naphthalene dicarboxylic acid, and these can be used alone or in combination of two or more.

In the xylylenediamine-based polyamide resin of this embodiment, it is preferable that 0 to 100 mol% of the diamine-derived structural units are derived from paraxylylenediamine and 100 to 0 mol% are derived from metaxylylenediamine, it is more preferable that 0 to 70 mol% are derived from paraxylylenediamine and 100 to 30 mol% are derived from metaxylylenediamine, it is even more preferable that 0 to 50 mol% are derived from paraxylylenediamine and 100 to 50 mol% are derived from metaxylylenediamine, and it is even more preferable that 0 to 20 mol% are derived from paraxylylenediamine and 100 to 80 mol% are derived from metaxylylenediamine.
In addition, the xylylenediamine-based polyamide resin in this embodiment is preferably one in which 70 mol % or more (preferably 80 mol % or more, more preferably 90 mol % or more) of the dicarboxylic acid-derived structural units are derived from sebacic acid and/or adipic acid (preferably adipic acid).
In any of the above embodiments, the total amount of the constitutional units derived from diamines does not exceed 100 mol %, and the total amount of the constitutional units derived from dicarboxylic acids does not exceed 100 mol %.

The xylylenediamine-based polyamide resin is mainly composed of diamine-derived structural units and dicarboxylic acid-derived structural units, but does not completely exclude other structural units. It goes without saying that it may contain structural 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 structural units constituting the xylylenediamine-based polyamide resin, the total number of diamine-derived structural units and dicarboxylic acid-derived structural units is the largest among all structural units. In this embodiment, the total of diamine-derived structural units and dicarboxylic acid-derived structural units in the xylylenediamine-based polyamide resin preferably accounts for 90% by mass or more of the total structural units, more preferably 95% by mass or more, and even more preferably 98% by mass or more.

One example of a blend form of the thermoplastic resin in the thermoplastic resin component is a blend of 80 to 100 parts by mass of xylylenediamine-based polyamide resin and 20 to 0 parts by mass of an aliphatic polyamide resin (preferably polyamide 66), and preferably a blend of 85 to 99 parts by mass of a xylylenediamine-based polyamide resin and 15 to 1 part by mass of an aliphatic polyamide resin.

The content of the thermoplastic resin (preferably polyamide resin) in the thermoplastic resin component is preferably 80% by mass or more, more preferably 85% by mass or more, even more preferably 90% by mass or more, and even more preferably 95% by mass or more. By making it equal to or more than the lower limit, the mechanical strength of the molded article tends to be improved. The upper limit of the content of the thermoplastic resin in the thermoplastic resin component is a value at which the total of the thermoplastic resin and the metal acetate is 100% by mass.
As described later, when a portion of the components contained in the thermoplastic resin component is made into a masterbatch, the amount including the thermoplastic resin for making the masterbatch is defined as the content of the thermoplastic resin.
The thermoplastic resin component in the present embodiment may contain only one type of each thermoplastic resin, or may contain two or more types. When two or more types are contained, it is preferable that the total amount is in the above range.

On the other hand, in this embodiment, at least one type of metal acetate is contained in an amount of 0.05 to 0.50 parts by mass per 100 parts by mass of the thermoplastic resin component. By containing 0.05 parts by mass or more of the metal acetate, thickening of the thermoplastic resin component can be suppressed, and impregnation of the thermoplastic resin component into the long fibers can be effectively promoted. As a result, the long fibers are less likely to break, and the productivity of the fiber reinforced resin material is improved. On the other hand, by making the content of the metal acetate 0.50 parts by mass or less per 100 parts by mass of the thermoplastic resin component, the mechanical strength of the obtained fiber reinforced resin material and further the molded product obtained from the fiber reinforced resin material can be increased.
The fiber reinforced resin material of the present embodiment may contain only one type of metal acetate salt, or may contain two or more types. When two or more types are contained, the total amount falls within the above range.

The metal acetate is preferably an alkali metal acetate or an alkaline earth metal acetate, and more preferably an alkali metal acetate. In this specification, the alkali metal means lithium, sodium, potassium, rubidium, cesium, and francium, and is preferably sodium and potassium, and more preferably sodium. In this specification, the alkaline earth metal means beryllium, magnesium, calcium, strontium, barium, and radium, and is preferably magnesium and calcium.
In this embodiment, the metal acetate preferably includes at least one selected from sodium acetate, calcium acetate, and magnesium acetate, and more preferably includes sodium acetate.

The thermoplastic resin component in this embodiment may contain other components in addition to the thermoplastic resin and the metal acetate.
Other components include nucleating agents, release agents, antioxidants, hydrolysis inhibitors, flame retardants, flame retardant assistants, reinforcing fillers, pigments, UV absorbers, antistatic agents, antifogging agents, plasticizers, dispersants, and antibacterial agents.

The nucleating agents are preferably talc and calcium carbonate, more preferably talc.
The lower limit of the average particle size of the nucleating agent is preferably 0.1 μm or more, more preferably 1 μm or more, and even more preferably 3 μm or more.The upper limit of the average particle size of the nucleating agent is preferably 40 μm or less, more preferably 30 μm or less, even more preferably 28 μm or less, even more preferably 15 μm or less, and even more preferably 10 μm or less.
The content of the nucleating agent is preferably 0.1 to 2.0 parts by mass per 100 parts by mass of the thermoplastic resin component.
The thermoplastic resin component may contain only one type of nucleating agent, or may contain two or more types. When two or more types are contained, the total amount is preferably within the above range.

It is preferable to incorporate a release agent into the thermoplastic resin component in order to improve releasability during molding. Examples of release agents include carboxylic acid amide waxes, bisamide waxes, and metal salts of long-chain fatty acids, with metal salts of long-chain fatty acids being preferred.

The long-chain fatty acid metal salt is a metal salt of a long-chain fatty acid having 16 to 36 carbon atoms, and examples thereof include calcium stearate, calcium montanate, sodium montanate, zinc stearate, aluminum stearate, sodium stearate, and lithium stearate.
For other details regarding the release agent, reference can be made to the descriptions in paragraphs 0060 to 0063 of JP2012-132027A, the contents of which are incorporated herein by reference.

The content of the release agent is preferably 0.001 to 1.0 part by mass, and more preferably 0.005 to 0.7 part by mass, per 100 parts by mass of the thermoplastic resin component. By making the content equal to or greater than the lower limit, it is possible to achieve a sufficient release effect and improve moldability, while by making the content equal to or less than the upper limit, it is possible to maintain high mechanical strength of the obtained fiber reinforced resin material, and further of the molded product molded from the fiber reinforced resin material.

In addition, it is preferable that the thermoplastic resin component in this embodiment does not substantially contain a reinforcing material. By making the thermoplastic resin component substantially free of a reinforcing material, the fluidity of the thermoplastic resin component can be further improved. Here, "substantially free" means that the content of the reinforcing material is 5% by mass or less of the thermoplastic resin component, more preferably 3% by mass or less, and even more preferably 1% by mass or less.

Next, the inorganic fibers to be impregnated with the thermoplastic resin component will be described.
The inorganic fibers used in this embodiment are so-called long fibers having a number average fiber length of 3 mm or more. When long fibers are used, a decrease in productivity is likely to occur, but this point is effectively avoided by using a metal acetate in this embodiment.
Examples of the inorganic fibers contained in the fiber reinforced resin material of the present embodiment include carbon fibers and/or glass fibers, with glass fibers being preferred.

In the present embodiment, the inorganic fiber refers to a fibrous inorganic material, and more specifically, it is preferable for the inorganic fiber to have a chopped shape in which 1,000 to 10,000 inorganic fibers are bundled together and cut to a predetermined length.
The inorganic fibers in this embodiment are so-called long fibers having a number average fiber length of 3 mm or more, but the length can be appropriately determined depending on the application, etc.
The inorganic fibers in this embodiment preferably have a number average fiber length of 5 mm or more, more preferably 2 cm or more, even more preferably 10 cm or more, and even more preferably 1 m or more depending on the application. By making the length equal to or more than the lower limit, the mechanical strength of the obtained molded product can be further improved.
The number average fiber length of the inorganic fibers is usually 10,000 m or less, and more preferably 10 mm or less depending on the application.
In particular, when the number average fiber length of the inorganic fibers is 10 mm or less (preferably 4 to 10 mm, more preferably 5 to 10 mm), the fiber reinforced resin material is preferably in the form of pellets.
Furthermore, when the number average fiber length of the inorganic fibers is 2 cm or more (preferably 10 cm or more, and preferably 10,000 m or less), the fiber reinforced resin material is preferably a UD tape (unidirectional tape) or a cloth material (woven fabric), and is preferably a UD tape (unidirectional tape).
The number average fiber length is calculated by randomly extracting inorganic fibers to be measured for fiber length from an image obtained by observation with an optical microscope, measuring the long side of the fibers, and calculating the number average fiber length from the measured values. The observation is performed at a magnification of 20 times, and the number of fibers measured is 1,000 or more. The number average fiber length is roughly equivalent to the cut length.
The cross section of the inorganic fiber may be any shape, such as a circle, an ellipse, an oval, a rectangle, a shape in which both short sides of a rectangle are joined by a semicircle, a cocoon shape, etc., but a circle is preferable. Here, the circle includes not only a circle in the mathematical sense, but also what is usually called a circle in the technical field of the present invention.
The number average fiber diameter of the inorganic fibers is preferably 4.0 μm or more, more preferably 4.5 μm or more, and even more preferably 5.0 μm or more. The upper limit of the number average fiber diameter of the inorganic fibers is preferably 30.0 μm or less, more preferably 25.0 μm or less, and even more preferably 20.0 μm or less. The number average fiber diameter of the inorganic fibers is calculated from the measured value obtained by randomly extracting glass fibers to be measured for the fiber diameter from an image obtained by observation with an electron microscope, measuring the fiber diameter near the center. The magnification of the observation is 1,000 times, and the number of measurements is 1,000 or more. The number average fiber diameter of glass fibers having a cross section other than a circle is 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.
The glass fiber is a fiber obtained by melt spinning a glass such as E glass, C glass, A glass, S glass (D glass, M glass, and alkali-resistant glass), which is commonly supplied, but is not particularly limited as long as it can be made into a glass fiber. In the present invention, it is preferable to include E glass.
The glass fiber may be treated with a surface treatment agent.

Glass fibers are commercially available. Examples of commercially available products include ER2400T-423N manufactured by Nippon Electric Glass Co., Ltd., RS2400QR-843 manufactured by Nittobo Co., Ltd., and ER4301H-2400 manufactured by Chongqing International Composites Co., Ltd. (CPIC).

The content of inorganic fibers in the fiber reinforced resin material in this embodiment is 65 parts by mass or more, preferably 70 parts by mass or more, more preferably 80 parts by mass or more, even more preferably 90 parts by mass or more, even more preferably 110 parts by mass or more, and even more preferably 115 parts by mass or more, relative to 100 parts by mass of thermoplastic resin. By making it equal to or more than the lower limit, the mechanical strength of the obtained fiber reinforced resin material and further the molded product obtained from the fiber reinforced resin material tends to be further improved.
In addition, the content of inorganic fibers in the fiber reinforced resin material in this embodiment is 170 parts by mass or less, preferably 165 parts by mass or less, more preferably 160 parts by mass or less, even more preferably 150 parts by mass or less, even more preferably 140 parts by mass or less, and even more preferably 130 parts by mass or less, relative to 100 parts by mass of thermoplastic resin. By making it equal to or less than the upper limit, the production of the fiber reinforced resin material tends to be more stable.
The fiber reinforced resin material of the present embodiment may contain only one type of inorganic fiber, or may contain two or more types. When two or more types are contained, it is preferable that the total amount is in the above range.

In the fiber-reinforced resin material of this embodiment, the total amount of the thermoplastic resin and the inorganic fibers preferably accounts for 90% by mass or more of the fiber-reinforced resin material, and more preferably accounts for 95% by mass or more.

Next, a method for producing the fiber reinforced resin material of this embodiment will be described.
The method for producing a fiber-reinforced resin material of the present embodiment includes impregnating 100 parts by mass of a thermoplastic resin component containing 0.05 to 0.50 parts by mass of at least one metal acetate salt in 100 parts by mass of a thermoplastic resin component with 65 to 170 parts by mass of inorganic fibers having a number average fiber length of 2 cm or more. By adopting such a method, the inorganic fibers are not broken during the production process, and the fiber-reinforced resin material can be produced efficiently.
In the method for producing a fiber-reinforced resin material of this embodiment, it is preferable to make a master batch of the metal acetate with a thermoplastic resin, and then blend it with other components to obtain the thermoplastic resin component. By making the metal acetate into a master batch, basicity due to volatilization of acetic acid in the master batch process can be promoted, and breakage of inorganic fibers and acetic acid odor during the production of the fiber-reinforced resin material can be more effectively suppressed. Here, the other components are other components that may be blended into the thermoplastic resin or fiber-reinforced resin material, and are synonymous with the thermoplastic resin and other components described in the above-mentioned fiber-reinforced resin material, and the preferred ranges and blending ratios thereof are also the same.
The resin to be made into a masterbatch is a thermoplastic resin constituting the fiber reinforced resin material, and for example, when the thermoplastic resin contained in the fiber reinforced resin material is a polyamide resin, the thermoplastic resin to be made into a masterbatch is preferably a polyamide resin. Unless otherwise specified, the thermoplastic resin contained in the thermoplastic resin component in this embodiment means the thermoplastic resin used for making the masterbatch.
The concentration of the metal acetate in the master batch is preferably 0.50% by mass or more, more preferably 1.00% by mass or more, even more preferably 1.50% by mass or more, and may be 2.00% by mass or more. The concentration of the metal acetate in the master batch is preferably 4.50% by mass or less, more preferably 4.00% by mass or less, even more preferably 3.50% by mass or less, and may be 3.00% by mass or less.
The master batch may contain only one type of metal acetate salt, or may contain two or more types. When two or more types are contained, the total amount is preferably within the above range.

When the metal acetate salt is made into a masterbatch, it is preferable to blend it with a thermoplastic resin and other components that are added as necessary. The blend may be a dry blend or a melt blend, but a dry blend is preferable. By using a dry blend, decomposition of the thermoplastic resin can be effectively suppressed without giving it unnecessary heat history.

The fiber reinforced resin material of the present embodiment is usually produced by impregnating inorganic fibers with a molten thermoplastic resin component.
For example, when the fiber-reinforced resin material is in the form of pellets, roving fibers are used as the inorganic fibers, and while the inorganic fibers are being spread, the inorganic fibers are impregnated with a molten thermoplastic resin component, and then the inorganic fibers are taken up as strands and cut to the desired pellet length.
The cut length at this time is the number average fiber length of the inorganic fibers. Therefore, the preferred range of the cut length is the same as the number average fiber length of the inorganic fibers described above.

In addition, when the fiber reinforced resin material is a UD tape (unidirectional tape), roving fibers are used as the inorganic fibers, and the roving fibers are arranged at equal intervals and spread, and then the inorganic fibers are passed through an impregnation die. At this time, a melt of a thermoplastic resin component is supplied, and the inorganic fibers are impregnated with the thermoplastic resin component in the impregnation die. By such a process, a UD tape can be obtained. The impregnation die is preferably equipped with an impregnation roll. The impregnation roll allows the inorganic fibers to be efficiently impregnated with the thermoplastic resin component.
Another example of the production method when the fiber-reinforced resin material is a UD tape (unidirectional tape) is to use inorganic fibers arranged in one or more directions as inorganic fibers, extrude them into a film using an extruder and pass them between a pair of impregnated rolls, or to overlap a film made of a thermoplastic resin component and heat press them. In this case, an example of inorganic fibers arranged in one or more directions is a woven fabric of inorganic fibers. It is also preferable to heat press the woven fabric of inorganic fibers sandwiched between two films made of a thermoplastic resin component.

Another example is a fiber-reinforced resin material in which inorganic fiber nonwoven fabric is used as the inorganic fiber, and is layered on a film made of a thermoplastic resin component and heat-pressed.

Next, a molded article formed from the fiber reinforced resin material of this embodiment will be described.
The type of molded product formed from the fiber reinforced resin material of this embodiment is not particularly limited. The molded product is not limited to a final product, but also includes various parts. The molded product of this embodiment is preferably used as a structural member part, a portable electronic device part, a vehicle and medical device part, other electronic parts including electric circuits, food and pharmaceutical containers, and a composite material for forming these.

The present invention will be described in more detail below with reference to examples. The materials, amounts, ratios, processing contents, processing procedures, etc. shown in the following examples can be appropriately changed without departing from the spirit of the present invention. Therefore, the scope of the present invention is not limited to the specific examples shown below.
If the measuring instruments used in the examples are difficult to obtain due to discontinuation or the like, measurements can be made using other instruments with equivalent performance.

1. Raw material MXD6: polyamide resin synthesized from metaxylylenediamine and adipic acid, manufactured by Mitsubishi Gas Chemical Company, Inc., #6000
PA66: Polyamide 66, manufactured by DuPont, Zytel 101NC-10
Talc: MS talc, manufactured by Nippon Talc Co., Ltd. StCa: calcium stearate, manufactured by Nitto Kasei Kogyo Co., Ltd. AcNa: sodium acetate (anhydrous), manufactured by Daito Kagaku Co., Ltd. Glass fiber: glass fiber roving, manufactured by Chongqing International Composite Materials Co., Ltd. (CPIC), ER4301H-2400 (number average fiber diameter of monofilament: 17 μm, TEX number: 2400 TEX)

<Masterbatch manufacturing>
A masterbatch of sodium acetate (masterbatch concentration: 2.60% by mass) was produced as follows.
5,000 g of polyamide MXD6 #6000 and 135 g of sodium acetate were dry-blended, and then fed from a top feed port of a twin-screw extruder (product name: TEM26SS, manufactured by Shibaura Machine Co., Ltd.) and melt-kneaded at a cylinder setting temperature of 260° C. and a screw rotation speed of 200 rpm to obtain a master batch of sodium acetate.

2. Examples 1 to 4 and Comparative Examples 1 to 3
<Method of manufacturing resin pellets>
The components listed in Table 1 except for the glass fiber were dry-blended, and then fed from the top feed port of a twin-screw extruder (product name: TEM26SS, manufactured by Shibaura Machine Co., Ltd.) in the ratio (unit: mass parts) shown in Table 1 below. The cylinder temperature was set to the melting point of the polyamide resin + 40 ° C., and the screw rotation speed was 200 rpm, and the melt of the resin components was introduced into the impregnation tank. The temperature in the impregnation tank was set to the melting point of the polyamide resin + 80 ° C., and four glass fiber rovings were heated to a preheater temperature of 200 ° C., and then introduced into the impregnation tank equipped with a resin impregnation roll through a crosshead. The glass fiber rovings were impregnated with the melt of the resin components obtained above while being opened and pulled, and then taken up as strands from a nozzle with an inner diameter of 1.9 mm at a take-up speed of 10 m / min, and cut to a length of 6 mm to obtain pellets. The cut length and the fiber length of the glass fiber in the pellets were the same length.

<Long fiber productivity>
The production was carried out for 10 hours, and the time from the start of production until the roving broke was observed. If even one of the four rovings broke, it was judged to have broken.

<Ash content (pellets)>
The pellets obtained by the above manufacturing method were dried at 120°C for 4 hours, weighed in a porcelain crucible, and incinerated for 2 hours in an electric furnace maintained at 650°C. The ash content (unit: mass%) was calculated from the mass before and after the incineration.

<Specific gravity>
The pellets obtained by the above manufacturing method were dried at 120° C. for 4 hours, and then injection molded into ISO tensile test pieces (4 mm thick) using an injection molding machine (manufactured by Shibaura Machine Co., Ltd., “EC75SX”) under conditions of a cylinder temperature of 280° C., a mold temperature of 130° C., and a molding cycle of 50 seconds. The specific gravity of the obtained molded body was measured by the Archimedes method in accordance with ISO 1183.

<Method of measuring crystallization temperature (Tcc)>
The crystallization temperature was measured in accordance with JIS K7121 and K7122.
Specifically, a differential scanning calorimeter was used, and the polyamide resin was placed in the measurement pan of the differential scanning calorimeter, heated to 30 to 300° C. at a heating rate of 20° C./min under a nitrogen atmosphere, held at 300° C. for 3 minutes, and then cooled at a cooling rate of 10° C./min. The peak temperature of the exothermic peak observed when the temperature was lowered was measured to determine the crystallization temperature during cooling (Tcc, unit: ° C.).
As the differential scanning calorimeter, a "DSC7020 AUTO" manufactured by SII Nano Technology Co., Ltd. was used.

<Flexural strength and flexural modulus>
The pellets obtained by the above manufacturing method were dried at 120°C for 4 hours, and then injection molded into ISO tensile test pieces (4 mm thick) using an injection molding machine (manufactured by Shibaura Machine Co., Ltd., "EC75SX") under conditions of a cylinder temperature of 280°C, a mold temperature of 130°C, and a molding cycle of 50 seconds.
In accordance with ISO 178, the flexural strength (unit: MPa) and flexural modulus (unit: GPa) were measured at a temperature of 23° C. using the above ISO tensile test pieces (4 mm thick).

<Charpy impact strength>
The pellets obtained by the above manufacturing method were dried at 120°C for 4 hours, and then injection molded into ISO tensile test pieces (4 mm thick) using an injection molding machine (manufactured by Shibaura Machine Co., Ltd., "EC75SX") under conditions of a cylinder temperature of 280°C, a mold temperature of 130, and a molding cycle of 50 seconds.
The notched Charpy impact strength was measured according to the ISO 179 standard.

As is clear from the above results, in the present invention (Examples 1 to 4), breakage of the long fibers could be effectively suppressed, and fiber-reinforced resin materials (resin pellets) could be efficiently produced. Furthermore, the molded products obtained from the fiber-reinforced resin materials also had high mechanical strength. When metal acetate was not included (Comparative Examples 1 and 2), the roving fibers broke during production, resulting in low productivity. On the other hand, when metal acetate was blended in a ratio of more than 0.50 parts by mass per 100 parts by mass of the thermoplastic resin component (Comparative Example 3), fiber-reinforced resin materials (resin pellets) could be efficiently produced, but the mechanical strength of the molded products obtained from the fiber-reinforced resin materials was poor.

Claims (15)

Contains 65 to 170 parts by mass of inorganic fibers having a number average fiber length of 3 mm or more per 100 parts by mass of a thermoplastic resin component;
The fiber reinforced resin material contains 0.05 to 0.50 parts by mass of at least one metal acetate salt per 100 parts by mass of the thermoplastic resin component. The fiber-reinforced resin material according to claim 1, wherein the metal acetate salt comprises at least one selected from sodium acetate, calcium acetate, and magnesium acetate. The fiber-reinforced resin material according to claim 1 or 2, wherein the inorganic fibers include glass fibers and/or carbon fibers. The fiber-reinforced resin material according to claim 1 or 2, wherein the inorganic fibers include glass fibers. The fiber-reinforced resin material according to any one of claims 1 to 4, wherein the thermoplastic resin component includes a polyamide resin. The fiber-reinforced resin material according to claim 5, wherein the polyamide resin contains diamine-derived structural units and dicarboxylic acid-derived structural units, 70 mol% or more of the diamine-derived structural units are derived from xylylenediamine, and 70 mol% or more of the dicarboxylic acid-derived structural units are derived from an α,ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms. The fiber-reinforced resin material according to any one of claims 1 to 6, wherein the number average fiber length of the inorganic fibers is 10 mm or less. The fiber-reinforced resin material according to any one of claims 1 to 6, wherein the number average fiber length of the inorganic fibers is 2 cm or more. The fiber-reinforced resin material according to any one of claims 1 to 7, wherein the fiber-reinforced resin material is in the form of pellets. The fiber-reinforced resin material according to any one of claims 1 to 6 and 8, wherein the fiber-reinforced resin material is a UD tape (unidirectional tape). A molded product formed from the fiber-reinforced resin material according to any one of claims 1 to 10. A method for producing a fiber-reinforced resin material, comprising impregnating 100 parts by mass of a thermoplastic resin component containing 0.05 to 0.50 parts by mass of at least one metal acetate salt in 100 parts by mass of a thermoplastic resin component with 65 to 170 parts by mass of inorganic fibers having a number average fiber length of 2 cm or more. The method for producing the fiber-reinforced resin material according to claim 12 includes forming a master batch of the metal acetate salt with a thermoplastic resin, and then blending it with other components to obtain the thermoplastic resin component. The method for producing a fiber-reinforced resin material according to claim 13, wherein the blend is a dry blend. The method for producing a fiber-reinforced resin material according to any one of claims 12 to 14, wherein the fiber-reinforced resin material is the fiber-reinforced resin material according to any one of claims 1 to 10.