JP2019059805A - Pellet, molding, and method for producing pellet - Google Patents

Abstract

To provide a pellet which is hardly broken and is excellent in a feed property, a molding, and a method for producing the pellet.SOLUTION: A pellet contains 65-170 pts.mass of a flat glass fiber having a cross section with flatness of 2.3-5.0 to 100 pta.mass of a resin component, where 85 mass% or more of the resin component is a polyamide resin that is composed of a diamine-derived constitutional unit and a dicarboxylic acid-derived constitutional unit, in which 70 mol% or more of the diamine-derived constitutional unit is derived from xylylenediamine and a relative viscosity in 96 mass% sulphuric acid solution according to ISO 307 is 1.8-4.0, and a pellet length is 2-8 mm.SELECTED DRAWING: None

Description

  The present invention relates to pellets, molded articles and methods for producing pellets. In particular, the present invention relates to a pellet, a molded article, and a method for producing the pellet, which are less likely to be cracked during production.

  Resin molded articles containing glass fibers are excellent in mechanical strength, heat resistance, chemical resistance and the like, and are used as parts in the automotive field, electrical and electronic equipment field, precision machinery field and the like. Furthermore, with the recent demand for weight reduction of parts, parts are being miniaturized and thinned.

  Under such circumstances, Patent Document 1 discloses a molded article made of a thermoplastic resin composition containing 70 to 35% by mass of a thermoplastic resin and 30 to 65% by mass of reinforcing fibers having a flat shape having a flatness of 2.3 or more. In the above, a fiber-reinforced thermoplastic resin molded article is disclosed in which the weight average fiber length of reinforcing fibers in the molded article is 1 mm or more.

JP, 2008-95066, A

As described above, it is known to blend glass fiber with thermoplastic resin such as polyamide resin. However, in recent years, the demand for polyamide resin blended with glass fiber is increasing, and development of new materials is required.
In particular, although a pellet in which glass fiber is blended with a polyamide resin is widely studied, it was found that the pellet is easily cracked at the time of production. Moreover, in order to suppress a crack, although it is possible to lengthen pellet length, if pellet length is lengthened, the feed property with respect to a molding machine will be inferior.
The present invention is intended to solve such problems, and relates to a pellet, a molded article, and a method for producing the pellet, which are resistant to cracking and excellent in feedability.

Based on the above problems, as a result of investigations by the present inventor, it is easy to impregnate the glass fiber with the resin by using the xylylene diamine-based polyamide resin having a predetermined relative viscosity and using the flat glass fiber. The inventors found that it is possible to produce hard-to-break pellets, and completed the present invention. The said subject was solved by <2>-<6> by the following means <1> specifically ,.
It is a pellet containing flat glass fiber 65-170 mass parts whose flatness of a cross section is 2.3-5.0 with respect to 100 mass parts of <1> resin components, Comprising: 85 mass% or more of the said resin component And a constituent unit derived from a diamine and a constituent unit derived from a dicarboxylic acid, wherein 70 mol% or more of the constituent unit derived from the diamine is derived from xylylene diamine and in a 96 mass% sulfuric acid solution defined by ISO 307 A pellet having a relative viscosity of 1.8 to 4.0 and a pellet length of 2 to 8 mm.
<2> The resin component further contains at least one kind of aliphatic polyamide resin consisting of polyamide 6 and polyamide 66, and further, 3 to 15% by mass of the aliphatic polyamide resin with respect to the total of the resin components The pellet as described in <1> containing.
The pellet as described in <1> or <2> whose number average fiber length of <3> said flat glass fiber is 2-8 mm.
<4><1>-<3> which 50 mol% or more of the structural unit derived from the dicarboxylic acid which comprises the said polyamide resin originates in the (alpha), (omega)-linear aliphatic dicarboxylic acid of 4-20 carbon atoms The pellet according to any one of the above.
The molded article shape | molded from the pellet as described in any one of <5><1>-<4>.
The flat glass fiber is impregnated with a melt of a resin component while opening a flat glass fiber roving having a flatness of 2.3 to 5.0 in a cross section, and then taken as a strand, The manufacturing method of the pellet as described in any one of <1>-<4> including cut | disconnecting in length of 2-8 mm.

  According to the present invention, it has become possible to provide a pellet, a molded article and a method for producing pellets which are not easily broken and which are excellent in feedability.

  Hereinafter, the contents of the present invention will be described in detail. In addition, in this specification, "-" is used in the meaning included including the numerical value described before and after that as a lower limit and an upper limit.

The pellet of the present invention is a pellet containing 65 to 170 parts by mass of flat glass fibers having a cross-sectional flatness of 2.3 to 5.0 with respect to 100 parts by mass of the resin component, and 85 mass of the resin component % Or more is composed of a constituent unit derived from a diamine and a constituent unit derived from a dicarboxylic acid, and 70% by mol or more of the constituent unit derived from the diamine is derived from xylylene diamine, and 96 mass% specified by ISO 307 A polyamide resin having a relative viscosity of 1.8 to 4.0 in a sulfuric acid solution, and having a pellet length of 2 to 8 mm.
With such a configuration, it is possible to provide a pellet, a molded article and a method for producing pellets which are hard to break and have excellent feedability.

<Xylylene diamine based polyamide resin>
In the pellet of the present invention, 85% by mass or more of the resin component is composed of a constituent unit derived from diamine and a constituent unit derived from dicarboxylic acid, and 70 mol% or more of the constituent unit derived from diamine is derived from xylylene diamine And the polyamide resin whose relative viscosity in the 96 mass% sulfuric acid solution prescribed | regulated to ISO307 is 1.8-4.0 is included.

The polyamide resin used in the present invention is composed of a constituent unit derived from diamine and a constituent unit derived from dicarboxylic acid, and a polyamide resin in which 70 mol% or more of the constituent unit derived from diamine is derived from xylylene diamine (herein, “Xylylenediamine-based polyamide resin” is sometimes included.
The constituent unit derived from diamine of the xylylene diamine-based polyamide resin is preferably 80 mol% or more, more preferably 85 mol% or more, still more preferably 90 mol% or more, still more preferably 95 mol% or more, still more preferably 99 mol% or more originates in xylylene diamine.
The structural unit derived from dicarboxylic acid of the xylylene diamine-based polyamide resin is preferably 50 mol% or more, more preferably 70 mol% or more, still more preferably 80 mol% or more, and still more preferably 90 mol% or more. Preferably 95 mol% or more, and even more preferably 99 mol% or more are derived from α, ω-linear aliphatic dicarboxylic acids having 4 to 20 carbon atoms.
The xylylene diamine is preferably para-xylylene diamine and meta-xylylene diamine, and more preferably at least meta-xylylene diamine.

  As a diamine other than metaxylylenediamine and paraxylylenediamine which can be used as a raw material diamine component of xylylenediamine-based polyamide resin, tetramethylenediamine, pentamethylenediamine, 2-methylpentanediamine, hexamethylenediamine, heptamethylene can be used. Aliphatic diamines such as diamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, dodecamethylenediamine, 2,2,4-trimethyl-hexamethylenediamine, 2,4,4-trimethylhexamethylenediamine, 1,3-butadiene Bis (aminomethyl) cyclohexane, 1,4-bis (aminomethyl) cyclohexane, 1,3-diaminocyclohexane, 1,4-diaminocyclohexane, bis (4-aminocyclohexyl) meta Alicyclic diamines such as 2, 2-bis (4-aminocyclohexyl) propane, bis (aminomethyl) decalin, bis (aminomethyl) tricyclodecane, bis (4-aminophenyl) ether, paraphenylene diamine, bis The diamine etc. which have aromatic rings, such as (aminomethyl) naphthalene, etc. can be illustrated, and 1 type, or 2 or more types can be mixed and used.

  Examples of preferred α, ω-linear aliphatic dicarboxylic acids having 4 to 20 carbon atoms for use as raw material dicarboxylic acid components of xylylene diamine-based polyamide resins include, for example, succinic acid, glutaric acid, pimelic acid, suberic acid, Aliphatic dicarboxylic acids such as azelaic acid, adipic acid, sebacic acid, undecanedioic acid and dodecanedioic acid can be exemplified, and one or more kinds can be mixed and used. Among these, adipic acid or sebacic acid is more preferable, and adipic acid is more preferable, because the melting point of the xylylene diamine-based polyamide resin falls within a suitable range for molding and processing.

  Examples of the dicarboxylic acid component other than the α, ω- straight chain aliphatic dicarboxylic acid having 4 to 20 carbon atoms include phthalic acid compounds such as isophthalic acid, terephthalic acid and orthophthalic acid, 1,2-naphthalenedicarboxylic acid, 1, 3-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 1,6-naphthalenedicarboxylic acid, 1,7-naphthalenedicarboxylic acid, 1,8-naphthalenedicarboxylic acid, 2,3- Examples thereof include naphthalenedicarboxylic acid compounds such as naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid and 2,7-naphthalenedicarboxylic acid, and one kind or a mixture of two or more kinds can be used.

  Although the xylylene diamine-based polyamide resin is mainly composed of a constituent unit derived from a diamine and a constituent unit derived from a dicarboxylic acid, the constituent units other than these are not completely eliminated, and ε-caprolactam or lauro It goes without saying that structural units derived from lactams such as lactam and the like and aliphatic aminocarboxylic acids such as aminocaproic acid and aminoundecanoic acid may be included. Here, the main component means that the total number of the structural unit derived from a diamine and the structural unit derived from a dicarboxylic acid among the structural units constituting the xylylene diamine-based polyamide resin is the largest among all the structural units. In the present invention, in the xylylenediamine-based polyamide resin, the total of the constituent unit derived from a diamine and the constituent unit derived from a dicarboxylic acid preferably accounts for 90% or more of the total constituent units, and more preferably 95% or more. .

The relative viscosity of the xylylenediamine-based polyamide resin used in the present invention in a 96% by mass sulfuric acid solution defined by ISO 307 is 1.8 to 4.0. When the relative viscosity is less than 1.8, the viscosity of the resin component becomes low, and when the strand is pulled from the impregnation die, the resin sags and the impregnation property is insufficient. Therefore, when passing through a take-up machine or a pelletizer, pellet cracking frequently occurs. When the relative viscosity exceeds 4.0, the resin component does not impregnate to the inside of the roving because the viscosity of the resin component is high, and the impregnation becomes insufficient. Therefore, when passing through a take-up machine or a pelletizer, pellet cracking frequently occurs.
The lower limit value of the relative viscosity is preferably 2.0 or more, more preferably 2.2 or more, and still more preferably 2.5 or more. In addition, the upper limit value of the relative viscosity is preferably 3.5 or less, more preferably 3.0 or less, and still more preferably 2.8 or less.
The relative viscosity is measured according to the method described in the examples below.

The melting point of the xylylene diamine-based polyamide resin is preferably 150 to 350 ° C., more preferably 180 to 330 ° C., still more preferably 200 to 330 ° C., and preferably 200 to 320 ° C. More preferred.
In the present invention, the melting point refers to the temperature at the peak top of the endothermic peak at the time of temperature rise observed by the DSC (differential scanning calorimetry) method.
For measurement, a DSC meter is used, the sample amount is about 1 mg, nitrogen is flowed at 30 mL / min as an atmosphere gas, and the temperature rise rate is 10 ° C./min from room temperature to a temperature higher than expected melting point The melting point can be determined from the temperature of the peak top of the endothermic peak observed when heating and melting. As a DSC measuring instrument, Shimadzu Corporation (SHIMADZU CORPORATION) company make, DSC-60 can be used.

  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, and still more preferably 10,000 or more, More preferably, it is at least 15,000. 35,000 or less is preferable, 30,000 or less is more preferable, 28,000 or less is more preferable, and 26,000 or less is still more preferable. Heat resistance, an elastic modulus, dimensional stability, and moldability will become better in it being such a range.

The lower limit value of the content of the xylylenediamine-based polyamide resin in the resin component is 85% by mass or more, and more preferably 88% by mass or more. The upper limit of the content of the xylylenediamine-based polyamide resin in the resin component may be 100% by mass, but is preferably 97% by mass or less, and more preferably 95% by mass or less .
The resin component may contain only one kind of xylylenediamine-based polyamide resin, or may contain two or more kinds. When it contains 2 or more types, it is preferable that a total amount becomes said range.
The xylylene diamine-based polyamide resin is also preferably contained 35% by mass or more, more preferably 40% by mass or more, and may be contained 42% by mass or more in the pellet of the present invention. In addition, the xylylene diamine-based polyamide resin is preferably contained in the pellet of the present invention in a proportion of 55% by mass or less, more preferably in a proportion of 50% by mass or less, and a proportion of 48% by mass or less May be included.

<Aliphatic polyamide resin>
In the pellet of the present invention, the resin component further contains at least one of aliphatic polyamide resins consisting of polyamide 6 and polyamide 66, and the aliphatic polyamide resin is 3 to 15% by mass with respect to the total of the resin components. Is preferred.
By blending the aliphatic polyamide resin in an amount of 3% by mass or more of the resin component, the crystallization rate can be increased. In addition, pellet cracking can be suppressed more effectively by blending the above-mentioned aliphatic polyamide resin in a proportion of 15% by mass or less of the resin component. That is, when the proportion of the aliphatic polyamide resin in the resin component exceeds 15% by mass, the crystallization speed of the aliphatic polyamide resin is fast, and therefore, when it passes through the take-up machine or the pelletizer, pellet cracking frequently occurs.
As for the compounding quantity of the said aliphatic polyamide resin, it is more preferable that it is 5 mass% or more, and it is more preferable that it is 12 mass% or less.
Here, polyamide 6 refers to a polyamide resin composed of a structural unit derived from ε-caprolactam, but the range (for example, 5 mol% or less, further 3 mol% or less, particularly 1 mol) does not deviate from the spirit of the present invention % Or less) may contain structural units derived from other raw material monomers. The same applies to polyamide 66.

<Other resin components>
The resin component may contain the xylylene diamine-based polyamide resin, a polyamide resin other than the aliphatic polyamide resin composed of the polyamide 6 and the polyamide 66, and a thermoplastic resin other than the polyamide resin.
Other polyamide resins include polyamide 4, polyamide 11, polyamide 12, polyamide 46, polyamide 610, polyamide 612, polyhexamethylene terephthalamide (polyamide 6T), polyhexamethylene isophthalamide (polyamide 6I), polyamide 66 / 6T, polyamide 9T, polyamide 9MT, polyamide 6I / 6T and the like. These other polyamide resins may contain only one type, or two or more types.
As thermoplastic resins other than polyamide resin, polyester resin, polyacetal resin, polyolefin resin, polycarbonate resin, aromatic vinyl compound polymer, polyphenylene ether resin, etc. are mentioned. These resins may contain only one type, or two or more types.
The blending amount of the other polyamide resin and the thermoplastic resin other than the polyamide resin is preferably 10% by mass or less of the resin component, more preferably 5% by mass or less, and further preferably 2% by mass or less It is particularly preferable to be substantially free. Substantially not containing means not to mix | blend positively, and it is not the meaning which excludes what is contained unintentionally, such as an impurity.

<Flat glass fiber>
The pellet of the present invention contains 65 to 170 parts by mass of flat glass fibers having a cross-sectional flatness of 2.3 to 5.0 with respect to 100 parts by mass of the resin component.
By using flat glass fibers, the impregnation property of the resin component can be improved.
The flatness is preferably 2.5 or more, more preferably 3.0 or more, and still more preferably 3.5 or more. Moreover, it is preferable that the said flat rate is 4.5 or less.
The blending amount of flat glass fibers is preferably 80 parts by mass or more, more preferably 90 parts by mass or more, and 100 parts by mass or more with respect to 100 parts by mass of the resin component. The amount of flat glass fiber is preferably 160 parts by mass or less, more preferably 150 parts by mass or less, and still more preferably 140 parts by mass or less, with respect to 100 parts by mass of the resin component. More preferably, it is 130 parts by mass or less, and may be 120 parts by mass or less. Flat glass fiber may contain only 1 type, and may contain 2 or more types. When it contains 2 or more types, it is preferable that a total amount becomes said range.
Furthermore, it is preferable that the total amount of the said resin component and the said flat glass fiber occupies 90 mass% or more, it is more preferable to occupy 95 mass% or more, and the pellet of this invention further occupies 97 mass% or more preferable.

  The number average fiber length of the flat glass fibers in the pellet of the present invention is preferably 2 mm or more, may be 3 mm or more, preferably 8 mm or less, and more preferably 7 mm or less. It may be 6 mm or less. The average fiber length of the glass fiber is a number average fiber length, and in the case of molding by a pultrusion method or the like, the cut length is the average fiber length of the glass fiber. That is, as an embodiment of the present invention, an embodiment in which the difference between the pellet length and the number average fiber length of flat glass is less than 1 mm (preferably 0.5 mm or less) is exemplified. More specifically, an embodiment in which the pellet length and the number average fiber length of the flat glass are the same is exemplified. Here, “identical” means that the pellet length and the number average fiber length of the glass fiber are the same as the cut length when molded by a pultrusion method etc. It does not mean the same. Needless to say, the pellets in the embodiment in which the pellet length and the number average fiber length of the flat glass are the same are not limited to the pellets produced by the pultrusion method.

<Other strengthening agent>
The pellet of the present invention may contain a glass fiber other than the flat glass fiber and a reinforcing agent other than the glass fiber. For example, glass fiber (round glass fiber) having a circular cross section, carbon fiber, aramid fiber, mica, wollastonite, potassium titanate, calcium carbonate, silica and the like can be mentioned. However, in the present invention, as the reinforcing agent, the blending amount of the reinforcing agent other than the flat glass fiber is preferably 10% by mass or less of the flat glass fiber contained in the pellet of the present invention, and is 5% by mass or less It is more preferable that it is 1 mass% or less.

<Other ingredients>
Other components may be blended in producing the pellet of the present invention. Other components include talc, mold release agents, copper halides (eg, copper iodide, copper chloride, copper bromide) and / or alkali metal halides (eg, potassium iodide, potassium bromide etc.) Etc., antioxidants such as hindered phenols and phosphites, mold release improvers, flame retardants and / or flame retardant aids, pigments, dyes, dispersants, antistatic agents, UV absorbers , Impact modifiers and other well known additives can be formulated.
The details of these additives can be referred to the description in paragraphs [0057] to [0063] of JP-A-2008-95066, the contents of which are incorporated herein.

<< Talc >>
The pellet of the present invention may contain talc. Crystallization can be promoted by blending talc.
It is preferable that it is 0.05-20.0 mass parts with respect to 100 mass parts of resin components, and, as for the compounding quantity of the talc in the pellet of this invention, it is more preferable that it is 0.1-10.0 mass parts. The amount is more preferably 0.15 to 5.0 parts by mass, and particularly preferably 0.2 to 1.2 parts by mass.
Talc may be used alone or in combination of two or more. In the case of two or more types, the total amount is preferably in the above range.

<< mold release agent >>
The pellet of the present invention may contain a release agent. By compounding a mold release agent, the releasability from the mold at the time of molding can be improved.
As a specific example of a mold release agent, the mold release agent as described in stage 0034-0040 of Unexamined-Japanese-Patent No. 2017-115093 is illustrated, and these content is integrated in this specification. The release agent in the present invention is preferably a fatty acid metal salt. As fatty acids, stearic acid and montanic acid are preferable, and stearic acid is more preferable. The metal constituting the fatty acid metal salt is preferably an alkaline earth metal, more preferably calcium and barium, and still more preferably barium.
When the pellet of the present invention contains a release agent, the content of the release agent is preferably 0.005 to 5.0 parts by mass with respect to 100 parts by mass of the resin component, and 0.01 to 3.0 It is more preferable that it is a mass part, It is further more preferable that it is 0.015-2.0 mass parts, It is still more preferable that it is 0.02-1.0 mass part.
A mold release agent may use only 1 type and may use 2 or more types together. In the case of two or more types, the total amount is preferably in the above range.

<Pellet length>
The pellet of the present invention has a pellet length of 2 to 8 mm. If the pellet length is less than 2 mm, the pellet is apt to break during the production of the pellet. Also, if the pellet length exceeds 8 mm, the pellet feedability at the time of producing a molded article will be inferior. Specifically, when the pellet length is long, hopper bridges may occur during molding.
The pellet length is preferably 2 mm or more, may be 3 mm or more, is preferably 8 mm or less, more preferably 7 mm or less, and may be 6 mm or less.
The pellet length refers to the length of the longest part of the pellet, and when it is manufactured via a strand, it is the same as the length (cut length) when the strand is cut. Thus, the pellet length is the number average length of the longest part of the pellet.

<Production method of pellet>
The method for producing the pellet of the present invention is not particularly limited, and can be produced according to a known method.
As an example of the manufacturing method of the pellet of the present invention, the flat glass fiber is impregnated with the molten material of the resin component while the flat glass fiber roving having an aspect ratio of a cross section of 2.3 to 5.0 is opened. Then, it is taken as a strand, and the manufacturing method of a pellet including cutting into 2 to 8 mm in length is mentioned.
In addition, the method described in paragraph 0034 of JP-A-2014-034606 can also be used.

<Molded item>
The present invention also discloses a molded article formed from the pellet of the present invention. The method for producing the molded article of the present invention is not particularly limited, and a molding method generally used for thermoplastic resins, that is, a molding method such as injection molding, hollow molding, extrusion molding, or press molding can be applied. .
As a molded article, a single layer film (which is a meaning including a single layer sheet), a multilayer film (which is a purpose including a multilayer sheet), a fiber, a yarn, a rope, a tube, a hose, various molding materials, a container, various parts, A finished product, a case, etc. are illustrated.

  The molded articles of the present invention are automobile parts such as automobiles, general machine parts, precision machine parts, electronic and electric parts, office equipment parts, building materials and housing related parts, medical devices, leisure sports goods, play equipment, medical goods And food, etc., widely used in containers for defense, aerospace products, etc.

  Hereinafter, the present invention will be more specifically described by way of examples. The materials, amounts used, proportions, treatment contents, treatment procedures and the like shown in the following examples can be appropriately changed without departing from the spirit of the present invention. Accordingly, the scope of the present invention is not limited to the specific examples shown below.

<Example of synthesis of MXD 6 (relative viscosity 1.7)>
Adipic acid 15000 g (102.6 mol) in a 50-liter heat-jacketed SUS reaction can equipped with a partial condenser, a total contraction, a pressure gauge, a nitrogen inlet, a liquid inlet, a resin extraction valve, and a stirrer. Then, 17.3 g (0.16 mol) of sodium hypophosphite and 12.1 g (0.15 mol) of sodium acetate were charged, and the inside of the reaction can was purged with nitrogen. Then, while passing nitrogen at a rate of 10 mL / min, the reaction can is heated to 170 ° C. under normal pressure to completely melt adipic acid, and then start dropping 13700 g (100.5 mol) of metaxylylenediamine did. During dropping of metaxylylenediamine, the temperature was continuously raised so that the reaction system was not solidified while removing water generated by the polycondensation from the system. The whole amount of metaxylylene diamine was dropped over 100 minutes, and the temperature in the reaction vessel was raised to 250 ° C. Then, the internal temperature was raised to 260 ° C. over 10 minutes with normal pressure, and while maintaining the internal temperature at 260 ° C., the pressure in the reaction vessel was reduced to 600 mmHg for 10 minutes using an aspirator and a pressure regulator. Stirring was stopped 5 minutes after reaching 600 mmHg, and after pressurizing the inside of the reaction can to 0.2 MPa with nitrogen, the resin extraction valve at the bottom of the reaction can was opened to draw out the polymer in strands and water cooled and then pelletized. It was pelletized to obtain about 25 kg of pellets.

Synthesis Example of MXD 6 (relative viscosity 4.5)
The pellet of S6001 manufactured by Mitsubishi Gas Chemical Co., Ltd. was charged into a stainless steel rotary drum heating device, and rotated at 5 rpm. The reaction system was heated up from room temperature to 140 ° C. under sufficient nitrogen substitution and further under a small nitrogen flow. When the temperature in the reaction system reached 140 ° C., the pressure was reduced to 1 torr or less, and the temperature in the system was further raised to 205 ° C. in 130 minutes. After the temperature in the system reached 205 ° C., the solid phase polymerization reaction was continued for 12 hours at the same temperature. After completion of the reaction, pressure reduction was completed, the temperature in the system was lowered under a nitrogen stream, and when reaching 60 ° C., the pellet was taken out.

<Relative viscosity>
The relative viscosity of the polyamide resin in a 96% by mass sulfuric acid solution defined by ISO 307 was measured as follows.
0.2 g of the polyamide resin was precisely weighed, and dissolved in 20 mL of a 96 mass% sulfuric acid aqueous solution with stirring at 25 ° C. After the polyamide resin was completely dissolved, 5 mL of the solution was immediately taken in a Cannonfence-type viscometer, and after standing for 10 minutes in a thermostat at 25 ° C., a drop time (t) was measured. Moreover, the fall time (t0) of the 96 mass% sulfuric acid aqueous solution itself was also measured similarly. The relative viscosity was calculated from t and t0 by the following equation.
Relative viscosity = t / t0

<Other raw materials>
MXD6 (relative viscosity 2.7): manufactured by Mitsubishi Gas Chemical Company, S6007
Polyamide 6: PA6, UBE nylon (registered trademark) 1012 B, Ube Industries polyamide 66: PA 66, amilan (registered trademark) CM 3001, Toray flat glass fiber roving: Nittobo, RSG 60QM-483HS (600 TEX), Flat rate: 4.0
Round glass fiber roving: Nippon Electric Glass EX-1400 (2400 TEX), Flatness about 1.0
MS Talc: Nippon Talc Barium Stearate: Sakai Chemical Industry Co.

<Measurement of Flatness>
The aspect ratio in the present invention is a value represented by major axis (a) / minor axis (b) based on the major axis (a) and minor axis (b) of the cross section perpendicular to the longitudinal direction of the glass fiber. The cross section of the glass fiber was measured from the photomicrograph to the actual size, and was calculated from the average value of any five places.

<Method for producing resin pellet>
Among the components described in Table 1, the components other than glass fiber are supplied from the top feed port in a twin-screw extruder (trade name: ZSK25, manufactured by Coperion) at a ratio (unit: mass part) shown in Table 1 below. The melt was kneaded at a set temperature of the cylinder at a melting point of the polyamide resin of + 40 ° C. and a screw rotation speed of 300 rpm to obtain a melt of the resin component.
After the glass fiber roving is opened and drawn, the melt of the resin component obtained above is impregnated with the resin component, and then it is drawn as a strand through an impregnation die at a drawing speed of 19 m / min. It cut so that it might become, and obtained the pellet. The cut length and the fiber length of the glass fiber in the pellet were the same length.

<Evaluation method of pellet cracking degree>
Among the pellets obtained above, the degree of cracked pellets was evaluated as follows with respect to 100 arbitrarily selected pellets.
A: Less than 10% of pellet cracks B: 10% or more of pellet cracks, less than 30% C: 30% or more of pellet cracks

<Evaluation of feedability>
Test piece of ISO dumbbell under the condition of cylinder temperature 280 ° C, mold temperature 130 ° C, screw rotation speed 80rpm, back pressure 5MPa using injection type machine (J55AD-2M made by Japan Steel Works, Ltd.) using standard type screw The biting property of the pellets in the hopper when 100 pieces were formed in a forming cycle of 45 seconds was evaluated.
A: Pellet biting ability was good and hopper bridge did not occur.
B: The pellet biteability was poor, and a hopper bridge occurred.

The results are shown in Table 1 below.

As is clear from the above results, the pellet of the present invention was low in pellet cracking and excellent in feedability (Examples 1 and 2).
On the other hand, when round glass fiber was used (comparative examples 1 and 2), pellet cracking occurred. In addition, when polyamide 6 or polyamide 66 having a high crystallization rate was used as the main component of the resin component (Comparative Examples 3 and 4), pellet cracking occurred. In addition, even when using the xylylene diamine-based polyamide resin whose crystallization rate is not fast, when the relative viscosity is not within the predetermined range (Comparative Examples 5 and 6), pellet cracking has occurred. Furthermore, when pellet length was long (comparative example 7), although the pellet crack was able to be controlled, feed nature became inferior. More specifically, a hopper bridge has occurred during molding.

Claims (6)

Pellets containing 65 to 170 parts by mass of flat glass fibers having a cross-sectional flatness of 2.3 to 5.0 with respect to 100 parts by mass of a resin component,
85% by mass or more of the resin component is composed of a constituent unit derived from a diamine and a constituent unit derived from a dicarboxylic acid, 70% by mol or more of a constituent unit derived from the diamine is derived from xylylenediamine, and in ISO 307 A pellet having a relative viscosity of 1.8 to 4.0 in a specified 96 mass% sulfuric acid solution and having a pellet length of 2 to 8 mm. The resin component further contains at least one of aliphatic polyamide resins consisting of polyamide 6 and polyamide 66,
The pellet according to claim 1, further comprising 3 to 15% by mass of the aliphatic polyamide resin based on the total of resin components. The pellet according to claim 1 or 2, wherein the number average fiber length of the flat glass fibers is 2 to 8 mm. The 50% by mole or more of the structural unit derived from dicarboxylic acid constituting the polyamide resin is derived from an α, ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms. The pellet described in. The molded article shape | molded from the pellet of any one of Claims 1-4. The flat glass fiber is impregnated with a melt of a resin component while opening a flat glass fiber roving having a flatness of 2.3 to 5.0 in cross section, and then taken as a strand, 2 to 8 mm The manufacturing method of the pellet of any one of Claims 1-4 including cut | disconnecting to length.