JP6661914B2 - Polyamide resin composition, molded article and method for producing molded article - Google Patents

Description

  The present invention relates to a polyamide resin composition, a molded article, and a method for producing a molded article. In particular, it relates to a polyamide resin composition having a low haze when formed into a molded product.

Conventionally, a nucleating agent has been blended with a polyamide resin.
For example, Patent Document 1 discloses that a polyamide obtained by melt-polymerizing a diamine component containing at least 70 mol% of meta-xylylenediamine and a dicarboxylic acid component containing at least 70 mol% of adipic acid is further obtained by solid-phase polymerization. To 100 parts by weight of the obtained solid-phase polymerized polyamide, at least one selected from a diamide compound or a diester compound obtained from a fatty acid having 8 to 30 carbon atoms and a diamine or diol having 2 to 10 carbon atoms is 0.005 to 1. A polyamide resin composition containing 0 parts by weight is disclosed. Further, Patent Document 1 discloses that by using such a resin composition, when stored in a high-humidity atmosphere, when contacted with water or boiling water, or when heated to a glass transition temperature or higher, whitening hardly increases. Is described.

  On the other hand, in Patent Document 2, a layer (X) containing polypropylene as a main component, an adhesive layer (Y) made of an adhesive thermoplastic resin, and a gas barrier layer (Z) made of a polyamide resin composition (P) are formed from an inner layer. A multilayer container having three or more layers laminated on an outer layer in this order, wherein the polyamide resin composition (P) comprises a diamine unit containing at least 70 mol% of a metaxylylenediamine unit and an α, ω-linear component. 80 to 99.9% by mass of a polyamide resin (A) comprising a dicarboxylic acid unit containing 80 to 97 mol% of a chain aliphatic dicarboxylic acid unit and 20 to 3 mol% of an aromatic dicarboxylic acid unit, and an aliphatic polyamide resin ( B) A multilayer container comprising 20 to 0.1% by mass is disclosed. In Example 5 of Patent Document 2, it is described that calcium stearate is added to a polyamide resin.

JP 2000-248176 A JP 2011-37199 A

However, the inventors of the present application have studied and found that the molded products of the polyamide resin compositions described in Patent Documents 1 and 2 have high haze after boil treatment, water treatment or retort treatment. .
An object of the present invention is to solve such problems, and an object of the present invention is to provide a polyamide resin composition capable of obtaining a molded article having a low haze after boil treatment, water treatment, or retort treatment. I do. Further, the present invention provides a molded article using the polyamide resin composition and a method for producing the molded article.

Based on the above problems, as a result of the study by the present inventor, in addition to a predetermined nucleating agent, by blending a predetermined aliphatic metal salt, boiling, water treatment or whitening after performing retort treatment is performed. It has been found that the haze can be suppressed and the haze can be reduced, and the present invention has been completed.
Specifically, the above problem was solved by the following means <1>, preferably by <2> to <9>.
<1> 100 parts by weight of a polyamide resin composed of a diamine-derived structural unit and a dicarboxylic acid-derived structural unit, wherein at least 50 mol% of the diamine-derived structural unit is derived from at least one of meta-xylylenediamine and para-xylylenediamine. Against
0.01 to 2.0 parts by weight of a nucleating agent selected from a compound represented by the following general formula (1) and a compound represented by the following general formula (2);
A polyamide resin composition comprising 0.08 to 2.0 parts by weight of an aliphatic metal salt of stearic acid or montanic acid selected from a sodium salt, a calcium salt, and a magnesium salt;
General formula (1)
In the general formula (1), n is an integer of 0 to 2, and R ^{1 to} R ⁵ are each independently a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an alkyl group having 2 to 20 carbon atoms. An alkenyl group, an alkoxy group having 2 to 20 carbon atoms, a carbonyl group, a halogen atom or an aryl group having 6 to 20 carbon atoms, and R ⁶ is an alkyl group having 1 to 20 carbon atoms;
General formula (2)
In the general formula (2), R ⁷ is each independently a hydrocarbon group having 4 or more carbon atoms, and R ⁸ is each independently a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, An alkenyl group having 2 to 20 atoms, an alkoxy group having 2 to 20 carbon atoms, a carbonyl group, a halogen atom, or an aryl group having 6 to 20 carbon atoms.
<2> The polyamide resin composition according to <1>, wherein a weight ratio of the nucleating agent to the aliphatic metal salt (aliphatic metal salt / nucleating agent) is 3.0 or more.
<3> The polyamide resin according to <1> or <2>, wherein 50 mol% or more of the structural units derived from the dicarboxylic acid is derived from an α, ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms. Composition.
<4> The polyamide resin composition according to <1> or <2>, wherein 70 mol% or more of the structural units derived from dicarboxylic acid is derived from at least one of adipic acid and sebacic acid.
<5> The nucleating agent is a compound represented by the general formula (1), wherein R ¹ , R ² , R ⁴ and R ⁵ are hydrogen atoms, and R ³ and R ⁶ are each independently A compound having an alkyl group having 1 to 20 carbon atoms and a compound represented by the general formula (2), wherein R ⁷ is independently a hydrocarbon having 4 or more carbon atoms including a cyclic structure. The polyamide resin composition according to any one of <1> to <4>, wherein the group is a group wherein R ⁸ is a hydrogen atom.
<6> The polyamide resin composition according to any one of <1> to <5>, wherein the aliphatic metal salt contains calcium stearate.
<7> The polyamide resin composition according to any one of <1> to <6> is formed into a film having a thickness of 60 μm, and immersed in water at 90 ° C. for 30 minutes, after which the arithmetic average roughness Ra of the film surface is obtained. Is 70 nm or less, and the root-mean-square roughness Rq is 100 nm or less.
<8> A molded article obtained by molding the polyamide resin composition according to any one of <1> to <7>.
<9> The arithmetic mean roughness Ra of the surface of the molded article after immersing the molded article in water at 90 ° C. for 30 minutes is 70 nm or less, and the root-mean-square roughness Rq is 100 nm or less, according to <8>. Molding.

  ADVANTAGE OF THE INVENTION By this invention, it became possible to provide the polyamide resin composition from which the molded article with a low haze after performing a boil process, a water process, or a retort process is obtained. Further, it has become possible to provide a molded article using the polyamide resin composition and a method for producing the molded article.

  Hereinafter, the contents of the present invention will be described in detail. In the specification of the present application, “to” is used to mean that the numerical values described before and after it are included as the lower limit and the upper limit.

The polyamide resin composition of the present invention comprises a diamine-derived structural unit and a dicarboxylic acid-derived structural unit, and at least 50 mol% of the diamine-derived structural unit is derived from at least one of meta-xylylenediamine and para-xylylenediamine. A nucleating agent selected from the compound represented by the general formula (1) and the compound represented by the general formula (2) with respect to 100 parts by weight of the polyamide resin (hereinafter sometimes referred to as “specific polyamide resin”) Hereinafter, the “specific nucleating agent” may be used in an amount of 0.01 to 2.0 parts by weight, and an aliphatic metal selected from a sodium salt, a calcium salt, and a magnesium salt of stearic acid or montanic acid. It is characterized by containing 0.08 to 2.0 parts by weight of a salt (hereinafter sometimes referred to as “specific aliphatic metal salt”). With such a configuration, the haze of the molded article after the boil treatment, the water treatment, or the retort treatment is performed can be kept low. This mechanism is presumed to be due to the fact that the size of the crystal nucleus could be reduced by mixing the specific nucleating agent and the specific aliphatic metal salt. Conventionally, it has been known to mix a specific nucleating agent or a specific aliphatic metal salt. However, it has not been known that a specific nucleating agent is used in combination with a specific aliphatic metal salt, and that the haze can be reduced by such a combination. In particular, the present invention is extremely significant in that the haze after performing a boil treatment, a water treatment, or a retort treatment on a molded product can be significantly reduced.
Furthermore, in the molded article of the present invention, by using a specific nucleating agent and a specific aliphatic metal salt in combination, the surface roughness (Ra or Rq) can be reduced, and a void layer can be hardly formed. In addition, there is a tendency that the mechanical strength of the molded article after the boil treatment, the water treatment or the retort treatment is performed can be kept high, and the oxygen permeability coefficient can be kept low.

<Specific polyamide resin>
The polyamide resin composition of the present invention comprises a diamine-derived structural unit and a dicarboxylic acid-derived structural unit, and at least 50 mol% of the diamine-derived structural unit is derived from at least one of meta-xylylenediamine and para-xylylenediamine. Containing polyamide resin.

In the specific polyamide resin, preferably 70 mol% or more, more preferably 80 mol% or more, and still more preferably 90 mol% or more of the diamine-derived structural unit is contained in at least one of meta-xylylenediamine and para-xylylenediamine. Comes from. The upper limit is not particularly limited, but may be 100 mol%.
The xylylenediamine may be para-xylylenediamine, meta-xylylenediamine, or a mixture of both. As one embodiment of xylylenediamine used for the specific polyamide resin in the present invention, xylylenediamine consisting of 0 to 70 mol% of paraxylylenediamine and 100 to 30 mol% of metaxylylenediamine is exemplified. Xylylenediamine consisting of 0 to 30 mol% and 100 to 70 mol% of metaxylylenediamine is exemplified as a preferred embodiment.

Diamines other than meta-xylylenediamine and para-xylylenediamine that can be used as the raw material diamine component of the specific polyamide resin include tetramethylene diamine, pentamethylene diamine, 2-methylpentanediamine, hexamethylene diamine, heptamethylene diamine, and octadiamine. Aliphatic diamines such as methylene diamine, nonamethylene diamine, decamethylene diamine, dodecamethylene diamine, 2,2,4-trimethyl-hexamethylene diamine, 2,4,4-trimethylhexamethylene diamine, and 1,3-bis (amino Methyl) cyclohexane, 1,4-bis (aminomethyl) cyclohexane, 1,3-diaminocyclohexane, 1,4-diaminocyclohexane, bis (4-aminocyclohexyl) methane, 2,2-bis Alicyclic diamines such as 4-aminocyclohexyl) propane, bis (aminomethyl) decalin, bis (aminomethyl) tricyclodecane, bis (4-aminophenyl) ether, paraphenylenediamine, and bis (aminomethyl) naphthalene; Diamines having an aromatic ring and the like can be exemplified, and one kind or a mixture of two or more kinds can be used.
When a diamine other than xylylenediamine is used as the diamine component, the content is less than 50 mol%, preferably 30 mol% or less, more preferably 1 to 25 mol%, particularly preferably, of the diamine-derived structural unit. Used in a ratio of 5 to 20 mol%.

Further, the constituent unit derived from dicarboxylic acid preferably has 50 mol% or more, more preferably 70 mol% or more, still more preferably 80 mol% or more, particularly preferably 90 mol% or more of α having 4 to 20 carbon atoms. , Ω-linear aliphatic dicarboxylic acid. The upper limit is not particularly limited, but may be 100 mol%.
The dicarboxylic acid used as the raw material dicarboxylic acid component of the specific polyamide resin is preferably an α, ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms, and is preferably an α, ω-linear aliphatic dicarboxylic acid having 4 to 10 carbon atoms. More preferably, it is an aliphatic dicarboxylic acid.
As the α, ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms, which is preferably used as a raw material dicarboxylic acid component of the specific polyamide resin, for example, succinic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, adipine Examples thereof include aliphatic dicarboxylic acids such as acid, sebacic acid, undecandioic acid, dodecandioic acid, and adipic acid and sebacic acid are preferable, and adipic acid is preferable. The α, ω-linear aliphatic dicarboxylic acids having 4 to 20 carbon atoms can be used alone or as a mixture of two or more.
As an example of the embodiment of the dicarboxylic acid component in the present invention, an embodiment in which 70 mol% or more, preferably 90 mol% or more of the dicarboxylic acid-derived structural unit is adipic acid or sebacic acid (preferably adipic acid) is exemplified. .

  Examples of the dicarboxylic acid component other than the α, ω-linear 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; 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 acids such as isomers 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.

  When a dicarboxylic acid other than α, ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms is used as the dicarboxylic acid component, at least one of terephthalic acid and isophthalic acid is used in view of moldability and barrier properties. Preferably, it is used, and more preferably, isophthalic acid is used. The proportion of terephthalic acid and isophthalic acid is preferably 30 mol% or less of the dicarboxylic acid structural unit, more preferably 1 to 30 mol%, and particularly preferably 5 to 20 mol%.

  The specific polyamide resin in the present invention is composed of a diamine-derived structural unit and a dicarboxylic acid-derived structural unit, but does not exclude a structural unit other than a diamine-derived structural unit and a dicarboxylic acid-derived structural unit. As a component constituting the polyamide resin, lactams such as ε-caprolactam and laurolactam, and aliphatic aminocarboxylic acids such as aminocaproic acid and aminoundecanoic acid can be used as the copolymerization component within a range not to impair the effects of the present invention. These components are usually 3% by mass or less of the specific polyamide resin.

  The specific polyamide resin used in the present invention preferably has a number average molecular weight (Mn) of 6,000 to 30,000, more preferably 8,000 to 28,000, and still more preferably 9,000 to 26. , More preferably 10,000 to 24,000, particularly preferably 11,000 to 22,000. Within such a range, heat resistance, elastic modulus, dimensional stability, and moldability will be better.

In addition, the number average molecular weight (Mn) here is calculated from the terminal amino group concentration [NH ₂ ] (μ equivalent / g) and the terminal carboxyl group concentration [COOH] (μ equivalent / g) of the polyamide resin by the following formula. Is calculated.
Number average molecular weight (Mn) = 2,000,000 / ([COOH] + [NH ₂ ])

The specific polyamide resin used in the present invention has a molecular weight distribution (weight average molecular weight / number average molecular weight (Mw / Mn)) of preferably 1.8 to 3.1. The molecular weight distribution is more preferably 1.9 to 3.0, and still more preferably 2.0 to 2.9. By setting the molecular weight distribution in such a range, a composite material having excellent mechanical properties tends to be easily obtained.
The molecular weight distribution of the specific polyamide resin can be adjusted, for example, by appropriately selecting the type and amount of an initiator and a catalyst used during polymerization and polymerization reaction conditions such as reaction temperature, pressure, and time. It can also be adjusted by mixing a plurality of types of specific polyamide resins having different average molecular weights obtained under different polymerization conditions, or by separately precipitating the specific polyamide resin after polymerization.

  The molecular weight distribution can be determined by GPC measurement. Specifically, using "HLC-8320GPC" manufactured by Tosoh as a device and two "TSK gel Super HM-H" manufactured by Tosoh as a column, the eluent trifluoro Hexafluoroisopropanol (HFIP) with a sodium acetate concentration of 10 mmol / l, resin concentration of 0.02 wt%, column temperature of 40 ° C., flow rate of 0.3 ml / min, measured under the conditions of a refractive index detector (RI), and standard polymethyl It can be obtained as a methacrylate conversion value. The calibration curve is prepared by dissolving six levels of PMMA in HFIP and measuring.

In the present invention, the melting point of the specific polyamide resin is preferably from 150 to 350 ° C, more preferably from 180 to 300 ° C, and even more preferably from 180 to 250 ° C.
In addition, the melting point in the present invention is a temperature at a peak top of an endothermic peak at the time of temperature increase observed by a DSC (differential scanning calorimetry) method. For the measurement, for example, “DSC-60” manufactured by Shimadzu Corporation (SHIMADZU CORPORATION) was used, the sample amount was about 5 mg, nitrogen was flowed at 30 ml / min as an atmosphere gas, and the temperature was raised at a rate of 10 ° C./min. Heating and melting from room temperature (25 ° C.) to a temperature higher than the expected melting point under the conditions, then quenching the melted sample with dry ice, and raising the temperature again to a temperature higher than the melting point at a rate of 10 ° C./min. The temperature at the peak top of the endothermic peak observed in the above can be used as the melting point.

  Regarding the method for producing the specific polyamide resin, the description in paragraphs 0052 to 0053 of JP-A-2014-173196 can be referred to, and the contents thereof are incorporated in the specification of the present application.

  The polyamide resin composition of the present invention preferably contains the specific polyamide resin in a proportion of not less than 60% by weight of the composition, and may have a composition containing not less than 80% by weight of the composition. Further, the polyamide resin composition of the present invention may include only one specific polyamide resin, or may include two or more specific polyamide resins.

<Other polyamide resins>
The polyamide resin composition of the present invention may contain a polyamide resin other than the specific polyamide resin.
Examples of other polyamide resins include polyamide 6, 11, 12, 46, 66, 610, 612, 6I, 6/66, 6T / 6I, 6 / 6T, 66 / 6T, 66 / 6T / 6I, and polytrimethyl. Hexamethylene terephthalamide, polybis (4-aminocyclohexyl) methane dodecamide, polybis (3-methyl-4-aminocyclohexyl) methane dodecamide, polyundecamethylene hexahydroterephthalamide, and the like. The above “I” indicates an isophthalic acid component, and “T” indicates a terephthalic acid component.
The proportion of the other polyamide resin in the polyamide resin composition of the present invention, when blended, is preferably blended in the range of 0.5 to 50% by weight of the specific polyamide resin, and is preferably in the range of 3 to 30% by weight. It is more preferable to mix them.
As a blend form of the polyamide resin of the present invention, a form in which a specific polyamide resin and polyamide 6 are blended is exemplified. In the present embodiment, the polyamide 6 is preferably 5 to 20% by weight of the specific polyamide resin.
Further, a configuration in which other polyamide resin is not substantially blended may be adopted. The phrase “substantially not blended” means that, for example, the proportion of another polyamide resin is less than 5% by weight of the specific polyamide resin.

<Nucleating agent>
The polyamide resin composition of the present invention contains a nucleating agent selected from the compound represented by the general formula (1) and the compound represented by the general formula (2).
General formula (1)
In the general formula (1), n is an integer of 0 to 2, and R ^{1 to} R ⁵ are each independently a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an alkyl group having 2 to 20 carbon atoms. An alkenyl group, an alkoxy group having 2 to 20 carbon atoms, a carbonyl group, a halogen atom or an aryl group having 6 to 20 carbon atoms, and R ⁶ is an alkyl group having 1 to 20 carbon atoms.

In the general formula (1), n is preferably 1.
The alkyl group having 1 to 20 carbon atoms as R ^{1 to} R ⁵ is preferably an alkyl group having 1 to 10 carbon atoms, more preferably an alkyl group having 2 to 6 carbon atoms. . The alkyl group is preferably a straight-chain alkyl group.
The alkenyl group having 2 to 20 carbon atoms as R ^{1 to} R ⁵ is preferably an alkenyl group having 2 to 10 carbon atoms, more preferably an alkenyl group having 2 to 6 carbon atoms. . The alkenyl group is preferably a straight-chain alkenyl group.
The alkoxy group having 2 to 20 carbon atoms as R ^{1 to} R ⁵ is preferably an alkoxy group having 2 to 10 carbon atoms, and more preferably an alkoxy group having 2 to 6 carbon atoms. . The alkyl chain of the alkoxy group is preferably a linear alkyl chain.
As the halogen atom as R ^{1 to} R ⁵ , a fluorine atom and a chlorine atom are preferable.
The aryl group having 6 to 20 carbon atoms as R ^{1 to} R ⁵ is preferably a phenyl group.
In R ^{1 to} R ⁵ , one or more hydrogen atoms contained in these groups may be substituted with a substituent. When substituted, the substituent is preferably an OH group. When R ^{1 to} R ⁵ are substituted, it preferably has 1 to 3 substituents per group. However, in R ^{1 to} R ⁵ , the hydrogen atom contained in these groups is preferably not substituted with a substituent.

R ¹ , R ² , R ⁴ and R ⁵ are preferably each independently a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and more preferably each independently a hydrogen atom.
R ³ is independently preferably an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms or an alkoxy group having 2 to 20 carbon atoms, and the number of carbon atoms is preferably It is more preferably an alkyl group having 1 to 20 carbon atoms, further preferably an alkyl group having 1 to 10 carbon atoms, and particularly preferably an alkyl group having 2 to 6 carbon atoms. The alkyl group is preferably a straight-chain alkyl group.
In R ³ , one or more hydrogen atoms contained in R ³ may be substituted with a substituent. When substituted, the substituent is preferably an OH group. When R ³ is substituted, it preferably has 1 to 3 substituents per R ³ . However, it is preferred that R ³ is not substituted with a substituent.
Specific examples of R ³ _{include, -CH 3, -CH 2 CH 3} , -CH 2 CH 2 CH 3, -CH 2 CH 2 CH 2 CH 3, -CH 2 CH = CH 2, -CH (CH 3) _{CH = CH 2, -CH 2 CH} -X 1 -CH 2 -X 2, -CH 2 CH-X 3 -CH 2 CH 3, -CH 2 CH-X 4 -CH 2 OH or -CH ₂ OH-CH (OH) —CH ₂ OH (where X ^{1 to} X ⁴ are each an independent halogen group).

R ⁶ has the same meaning as R ³ described above, and the preferred range is also the same.

  Examples of the method for producing the compound represented by the general formula (1) include a method described in International Publication WO2005 / 111134 pamphlet and the like. It can be easily obtained as a commercial product, for example, Mirad NX8000 (manufactured by Milliken & Company).

General formula (2)
In the general formula (2), R ⁷ is each independently a hydrocarbon group having 4 or more carbon atoms, and R ⁸ is each independently a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, An alkenyl group having 2 to 20 atoms, an alkoxy group having 2 to 20 carbon atoms, a carbonyl group, a halogen atom, or an aryl group having 6 to 20 carbon atoms.
In the general formula (2), R ⁷ is each independently a hydrocarbon group having 4 or more carbon atoms, preferably a hydrocarbon group having a cyclic structure having 4 or more carbon atoms. It is more preferably a hydrocarbon group having a cyclic structure of 4 to 10, more preferably a hydrocarbon group having a cyclic structure of 5 to 8 carbon atoms, and a hydrocarbon having a cyclic structure of 6 carbon atoms. Particularly preferred is a group. The cyclic structure may be an alicyclic ring or an aromatic ring, but is preferably an alicyclic ring. The cyclic structure may have a substituent, but preferably has no substituent. When it has a substituent, the substituent is preferably an alkyl group.
R ⁸ has the same meaning as R ¹ in formula (1), and the preferred range is also the same. Accordingly, R ⁸ is preferably each independently a hydrogen atom.
The compound represented by the general formula (2) can be easily obtained as a commercial product, for example, Ngesta NU-100 (manufactured by Shin Nippon Rika).

The amount of the specific nucleating agent is 0.01 to 2.0 parts by weight based on 100 parts by weight of the specific polyamide resin. The lower limit of the amount is preferably 0.03 parts by weight or more, more preferably 0.05 parts by weight or more. The upper limit of the amount is preferably 1.0 part by weight or less, more preferably 0.7 part by weight or less, further preferably 0.5 part by weight or less, and more preferably 0.3 part by weight. It is particularly preferred that: With such a range, the haze after performing the boil treatment, the water treatment, or the retort treatment can be more effectively reduced.
The polyamide resin composition of the present invention may include only one specific nucleating agent, or may include two or more specific nucleating agents. When two or more types are included, the total amount is the above-mentioned amount.

<Specific aliphatic metal salt>
The polyamide resin composition of the present invention contains an aliphatic metal salt of stearic acid or montanic acid selected from a sodium salt, a calcium salt, and a magnesium salt.
The specific aliphatic metal salt is preferably a sodium salt, a calcium salt, or a magnesium salt of stearic acid, and more preferably calcium stearate.

The amount of the specific aliphatic metal salt is 0.08 to 2.0 parts by weight based on 100 parts by weight of the specific polyamide resin. The lower limit of the amount is preferably 0.1 part by weight or more, more preferably 0.2 part by weight or more, more preferably 0.3 part by weight or more, and 0.4 part by weight. It is particularly preferable that the above is satisfied. The upper limit of the amount is preferably 1.5 parts by weight or less, more preferably 1.0 part by weight or less, still more preferably 0.8 part by weight or less, and 0.6 part by weight. It is particularly preferred that: With such a range, the haze after performing the boil treatment, the water treatment, or the retort treatment can be more effectively reduced.
The polyamide resin composition of the present invention may contain only one kind of the specific aliphatic metal salt, or may contain two or more kinds. When two or more types are included, the total amount is the above-mentioned amount.

In the polyamide resin composition of the present invention, the weight ratio of the specific nucleating agent to the specific aliphatic metal salt (aliphatic metal salt / nucleating agent) is preferably 3.0 or more, more preferably 4.0 or more, and 5 or more. The above is more preferred. With such a ratio, the haze after performing the boil treatment, the water treatment, or the retort treatment can be more effectively reduced. Further, the surface roughness of the molded article after the boil treatment, the water treatment or the retort treatment can be effectively suppressed. The upper limit of the weight ratio between the specific nucleating agent and the specific aliphatic metal salt (aliphatic metal salt / nucleating agent) is not particularly limited, but may be, for example, 20.0 or less, and furthermore, 15 or less. In particular, it can be set to 12 or less.
In particular, the polyamide resin composition of the present invention is obtained by forming a polyamide resin composition into a film having a thickness of 60 μm, immersing the film in water at 90 ° C. for 30 minutes, and then calculating an arithmetic average roughness Ra of the film surface of 70 nm or less and a root mean square. A composition having a square root roughness Rq of 100 nm or less can be obtained. Although the lower limit of Rq is desirably 0 nm, for example, even if Rq is 35 nm, it is a sufficiently practical level.

<Other ingredients>
In addition to the above, other components can be blended in the polyamide resin composition of the present invention without departing from the spirit of the present invention. Examples of other components include resins other than the polyamide resin, and additives other than the specific nucleating agent and the specific aliphatic metal salt.

As a resin other than the polyamide resin, a polyester resin such as polyethylene terephthalate and polybutylene terephthalate, and a thermoplastic resin such as a polycarbonate resin and a polyacetal resin can be used.
Further, the polyamide resin composition of the present invention may have a configuration in which a resin component other than the polyamide resin is not substantially blended. For example, the other resin component may be used in an amount of 5% by weight based on the total amount of the resin component contained in the polyamide resin composition. Hereinafter, it may be 1% by weight or less, particularly 0.4% by weight or less.
Other additives include release agents, matting agents, heat stabilizers, weather stabilizers, ultraviolet absorbers, antioxidants, nucleating agents, plasticizers, flame retardants, antistatic agents, anti-coloring agents, impact resistance Additives such as improvers, clays and fillers such as layered silicates and the like can also be added, but are not limited to those described above, and various materials may be mixed. For details of these, the description of paragraphs 0130 to 0155 of Japanese Patent No. 489,982 and paragraphs 0029 to 0040 of JP-A-2009-120821 can be referred to, and the contents thereof are incorporated in the present specification.
Each of these components may be used alone or in combination of two or more.

<Production method of polyamide resin composition>
The method for producing the polyamide resin composition of the present invention is not particularly limited, but is preferably a method using a single-screw or twin-screw extruder having equipment capable of devolatilizing from a vent port as a kneader. The polyamide resin and the additive may be supplied to the kneader at one time, or other components may be sequentially supplied to the polyamide resin component. Further, two or more kinds of components selected from the respective components may be previously mixed and kneaded.

<Molded product>
The polyamide resin composition of the present invention can be formed into various molded products. The method for producing a molded article using the polyamide resin composition of the present invention is not particularly limited, and molding methods generally used for thermoplastic resins, that is, molding such as injection molding, hollow molding, extrusion molding, and press molding. The method can be applied.
Examples of the molded article include a single-layer film or sheet, a multilayer film or sheet, fiber, thread, rope, tube, hose, various molding materials, containers, various parts, finished products, housings, and the like. Further, the molded article (particularly, a film) may be stretched.
After the boil treatment, the molded article of the present invention is partially or entirely (preferably, a molded article having a thickness of 50 to 100 μm, particularly when the thickness is 60 μm). The arithmetic mean roughness Ra of the surface of the molded article can be set to 70 nm or less, more preferably 50 nm or less, particularly 30 nm or less. The lower limit of Ra is desirably 0 nm. For example, even if Ra is 25 nm, it is a sufficiently practical level.
After the boil treatment, the molded article of the present invention is partially or entirely (preferably, a molded article having a thickness of 50 to 100 μm, particularly when the thickness is 60 μm). , The root-mean-square roughness Rq can be set to 100 nm or less, further, 70 nm or less, particularly 50 nm or less. Although the lower limit of Rq is desirably 0 nm, for example, even if Rq is 35 nm, it is a sufficiently practical level.
After the boil treatment, the molded article of the present invention is partially or entirely (preferably, a molded article having a thickness of 50 to 100 μm, particularly when the thickness is 60 μm). The oxygen permeability coefficient can be 0.08 cc · mm / m ² · day · atm or less. The lower limit value of the oxygen permeability ^{coefficient, 0cc · mm / m 2 ·} day · atm is preferred, even ^{0.07cc · mm / m 2 · day} · atm is sufficient practical level.
Further, the molded article of the present invention (particularly, a single-layer film or sheet having a thickness described later, for example, when the thickness is 60 μm) can have a haze after boil treatment of 20% or less. , 5% or less. Further, the haze after the water treatment can be 5% or less, further 2.5% or less, and particularly 2% or less. Furthermore, the haze after the retort treatment can be reduced to 40% or less, further, 30% or less, and particularly, 28% or less. Here, the post-boil treatment, post-water treatment and retort treatment refer to those treated by the methods described in Examples described later. In addition, haze, Ra, Rq, and oxygen permeability coefficient also refer to values measured according to the method described in Examples described later. In addition, when it is difficult to obtain a device or the like used in the embodiment due to a waste plate or the like, another device having the same performance can be used. The same applies to other measurement methods.

<< Single-layer film or sheet >>
The thickness of the single-layer film or sheet can be 5 to 1000 μm, can be 15 to 500 μm, and can be 50 to 100 μm.
The single-layer film or sheet can be preferably used for wrapping, pouches of various shapes, lid materials for containers, packaging containers such as bottles, cups, trays and tubes.

<< Multilayer film or sheet >>
Examples of the multilayer film or sheet include a laminate of a single-layer film or sheet using the polyamide resin composition of the present invention and another resin film or sheet. Examples of the resin constituting the other resin film or sheet include a polyamide resin other than the specific polyamide resin, a polyolefin resin, and a polyester resin, and a polypropylene resin and a polyethylene terephthalate resin are preferable. These multilayer laminated films or sheets are produced by co-extrusion of the polyamide resin composition of the present invention and a resin composition containing another resin as a main component, and a single layer using the polyamide resin composition of the present invention. A method of bonding a film or sheet to another resin film or sheet with an adhesive or the like is exemplified.
The multilayer film or sheet can be preferably used for wrapping, pouches of various shapes, lid materials for containers, packaging containers such as bottles, cups, trays and tubes.

<< container >>
The polyamide resin composition of the present invention is preferably used for a single-layer or multilayer container. The shape of the container is not particularly limited, and may be, for example, a molded container such as a bottle, a cup, a tube, a tray, a tapperware, or a pouch, a standing pouch, or a bag-like container such as a zipper-type storage bag. Is also good. When the multilayer container has a flange portion, the flange portion may be subjected to special processing for providing an easy peel function.
Examples of the multilayer container include a container including a layer using the polyamide resin composition of the present invention and another resin layer. Such a multilayer container can be manufactured by any method such as extrusion molding, extrusion / blow molding and the like. For example, using a multilayer sheet manufacturing apparatus equipped with three extruders, a feed block, a T-die, a cooling roll, a winder, and the like, a composition mainly composed of a polypropylene resin (PP resin) from the first extruder. The extruded product is extruded from the second extruder, the adhesive resin is extruded from the third extruder, and the PP resin layer / adhesive layer / polyamide resin composition layer is fed through a feed block. A multi-layer sheet having three types and a five-layer structure of an adhesive layer and a PP resin layer is manufactured and softened by heating. Then, the sheet is brought into close contact with a mold by vacuum, air pressure, or a thermoforming method using both vacuum and air pressure. A method of forming a container and trimming the same to obtain a container may be used. Here, the sheet surface temperature during thermoforming is preferably from 130 to 200 ° C, more preferably from 150 to 180 ° C, from the viewpoint of shapeability. Note that the multilayer sheet manufacturing apparatus and the method of forming the container are not limited to these, and any method can be applied.
Further, an injection molding cup can be formed by an injection molding method, and a blow bottle can be formed by a blow molding method. After a preform is manufactured by injection molding, a bottle can be further formed by blow molding.
Further, it can be processed into a preform or bottle having a multilayer structure with PET or the like by a multilayer injection molding method or the like.

  The container (preferably a multi-layer container) can store and store various items whose contents are desired to be visualized in order to increase the customer's willingness to purchase. For example, processed marine products, processed livestock products, rice, and liquid foods may be mentioned. In particular, the heat sterilization treatment temperature is as high as 100 ° C. or more, and is suitable for storing foods that are easily affected by oxygen. For details thereof, the description in paragraphs 0032 to 0035 of JP-A-2011-37199 can be referred to, and the contents thereof are incorporated in the specification of the present application.

  Hereinafter, the present invention will be described more specifically with reference to examples. Materials, usage amounts, ratios, processing contents, processing procedures, and the like 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 described below.

<Raw materials>
Polyamide resin (S6007): MXD6, manufactured by Mitsubishi Gas Chemical, MX nylon S6007, melting point 237 ° C
Nucleating agent (NU-100): diamide-based nucleating agent, Nippon Rika, Ngester NU-100
Structural formula
Nucleating agent (NX8000): sorbitol-based nucleating agent, manufactured by Milliken & Company, Mirad NX8000
Structural formula
Aliphatic metal salt (StCa): calcium stearate, manufactured by Kanto Chemical Co., Ltd., 07105-01

Example 1
<Manufacture of polyamide resin film>
As shown in the table below, a polyamide resin, a nucleating agent, and an aliphatic metal salt are weighed to the amounts (parts by weight) shown in the table, blended by a tumbler, and then twin-screw extruder (Plastic Engineering Laboratory) From PTM-30), melted and extruded to produce a film (molded product) having a thickness of 60 μm. The temperature of the extruder was set at the melting point of the polyamide resin + 30 ° C.

<Measurement of haze>
The haze of the molded product (the film made of the polyamide resin composition obtained above) was measured by a transmission method using a haze value measuring device. In this example, a model: COH-300A manufactured by Nippon Denshoku Industries Co., Ltd. was used as a haze value measuring device. The unit is shown by%.
After the treatment, the haze was measured by the treatment method described in the table, and the haze was measured in the same manner as above.
The processing method is as follows.
Boil treatment: The film was immersed in water at 90 ° C. for 30 minutes.
Water treatment: The film was immersed in water at 23 ° C. for 24 hours.
Retort treatment: The film was treated with 121 ° C. high-pressure steam for 30 minutes.

<Measurement of arithmetic average roughness (Ra) of molded product surface>
The arithmetic mean roughness (Ra) of the surface of the molded product (the film made of the polyamide resin composition obtained above) subjected to the boil treatment was measured using a confocal laser microscope.
Specifically, using a confocal laser microscope (VK-X100) manufactured by Keyence, surface observation and measurement of the molded product were performed, and the surface roughness of the sample was quantified. The numerical value of the surface roughness was calculated according to JIS B0601 by calculating the arithmetic average roughness Ra. The unit is shown in nm.

<Measurement of root mean square roughness (Rq)>
Rq of the molded product (film comprising the polyamide resin composition obtained above) was measured according to the method described in JIS B0601. The unit is shown in nm.

<Measurement of void layer thickness ratio in molded product after boiling treatment>
The measurement of the ratio of the thickness of the void layer in the molded product after the boil treatment was performed using the polyamide resin film obtained above that had been subjected to the boil treatment.
Specifically, the polyamide resin composition film obtained above is subjected to a boil treatment, a section is formed by ion milling using IM-4000 manufactured by Hitachi, and the obtained molded product is scanned with a scanning electron microscope ( Hitachi S4800, SU8020). The void layer thickness ratio was calculated by dividing the observed thickness of the void layer by the thickness of the observed cross section of the molded article.
The void layer refers to a layer in which voids are formed in the molded product when the molded product is subjected to the boil treatment, and the distance from the end to the end of the portion where the void exists in the thickness direction of the observed cross section is defined as a void. It is called the thickness of the layer.
Specifically, the thickness of the void layer was calculated by the following equation.
Void layer thickness ratio (%) = Void layer thickness / Molded product thickness × 100

<Measurement of tensile modulus, breaking strength, and elongation at break>
The polyamide resin composition film obtained above and the polyamide resin composition film obtained by boil-treating the same, respectively, have a tensile modulus (unit: MPa), a breaking strength (MPa) according to ASTM-D882, The elongation at break (%) was measured.
In the measurement, a strip-shaped test piece having a width of 10 mm and a length of 120 mm was prepared from the film obtained above under an environment of 23 ° C. and 50% relative humidity (RH), and a strograph V1-C [Toyo Seiki Seisakusho Co., Ltd. Manufactured under the conditions of a distance between chucks of 50 mm and a pulling speed of 50 mm / min.

<Measurement of oxygen permeability coefficient>
For the polyamide resin composition film obtained above and the polyamide resin composition film obtained by boil processing, the oxygen permeability coefficient was measured using an oxygen permeability measuring device (model: OX-TRAN 2/21 manufactured by MOCON). ) Was measured in an atmosphere at 23 ° C. and a relative humidity of 60% according to ASTM-D3985. The value at the time of stabilization was defined as the oxygen permeability coefficient.

Examples 2 to 4, Comparative Examples 1 to 5
In Example 1, the raw materials were changed as shown in Table 1, and the other conditions were the same.

The results are shown in the table below.

As is clear from the above results, when the specific nucleating agent and the specific aliphatic metal salt are used in combination, the boil treatment, the water treatment, the haze after the retort treatment is small, and the whitening of the molded article using the polyamide resin composition is effective. (Examples 1-4). Also, the rate of change in the tensile modulus, breaking strength, and breaking elongation of the film after the boil treatment was small. In particular, when the weight ratio of the specific nucleating agent and the specific aliphatic metal salt (aliphatic metal salt / predetermined nucleating agent) is 3.0 or more, the haze after boil treatment, water treatment, and retort treatment is remarkably small, It was found that the rise in haze of a molded article using the polyamide resin composition was significantly suppressed (Examples 1, 3, and 4).
On the other hand, when one of the specific nucleating agent and the specific aliphatic metal salt is not contained or the content is small even if it is contained, the boil treatment, the water treatment, and the haze before the retort treatment are not much different from the examples. However, the haze after these treatments was significantly increased (Comparative Examples 1 to 5).

Claims (7)

Consisting of a diamine-derived structural unit and a dicarboxylic acid-derived structural unit, 50 mol% or more of the diamine-derived structural unit is based on 100 parts by weight of a polyamide resin derived from at least one of meta-xylylenediamine and para-xylylenediamine.
0.01 to 2.0 parts by weight of a nucleating agent selected from a compound represented by the following general formula (1) and a compound represented by the following general formula (2);
A polyamide resin composition comprising 0.08 to 2.0 parts by weight of calcium stearate ;
General formula (1)
In the general formula (1), n is an integer of 0 to 2, R ¹ , R ² , R ⁴ and R ⁵ are hydrogen atoms, and R ³ and R ⁶ each independently have a carbon atom number. 1-20 alkyl groups ;
General formula (2)
In the general formula (2), R ⁷ is each independently a hydrocarbon group having 4 or more carbon atoms including a cyclic structure, and R ⁸ is a hydrogen atom . The polyamide resin composition according to claim 1, wherein a weight ratio of the nucleating agent and the calcium stearate ( calcium stearate / nucleating agent) is 3.0 or more. 3. The polyamide resin composition according to claim 1, wherein 50 mol% or more of the constituent units derived from the dicarboxylic acid are derived from α, ω-linear aliphatic dicarboxylic acids having 4 to 20 carbon atoms. 4. The polyamide resin composition according to claim 1 or 2, wherein 70 mol% or more of the structural units derived from dicarboxylic acid is derived from at least one of adipic acid and sebacic acid. An arithmetic average roughness Ra of the film surface after forming the polyamide resin composition according to any one of claims 1 to 4 into a film having a thickness of 60 μm and immersing the film in water at 90 ° C. for 30 minutes. And a polyamide resin composition having a root mean square roughness Rq of 100 nm or less. A molded article obtained by molding the polyamide resin composition according to any one of claims 1 to 5 . Wherein after immersion for 30 minutes in 90 ° C. water moldings, arithmetic average roughness Ra of 70nm surface of a molded article or less, the root-mean-square roughness Rq is 100nm or less, the molded article according to claim 6.