JP6245948B2 - Polyamide resin composition - Google Patents

Description

  The present invention relates to a polyamide resin composition. More specifically, the present invention relates to a polyamide resin composition containing an N-vinyl lactam polymer that is useful as wallpaper, curtains, carpets and the like.

  Polyamide resins are widely used as wallpaper for interior walls of residences, commercial facilities, office buildings, and the like. However, the polyamide resin has strong hydrophobicity, and when the humidity of the room is increased, water droplets adhere to the wallpaper and cause mold and the like. Therefore, it is preferable to make the polyamide resin hydrophilic so that water droplets are diffused on the surface of the resin to facilitate drying.

On the other hand, N-vinyl lactam polymers represented by polyvinylpyrrolidone are used in a wide range of fields as safe water-soluble and hydrophilic polymers.
For example, Patent Document 1 discloses a vinylpyrrolidone copolymer which is a copolymer of a vinyl compound containing a functional group and N-vinyl-2-pyrrolidone, and a compound having two or more hydrazide functional groups in the molecule. It is disclosed that an aluminum plate can be hydrophilized by applying a hydrophilizing agent composition to an aluminum plate, drying and heat-treating it to form a film.

JP 2009-286865 A

As described above, although a technique capable of hydrophilizing the base material by applying and heat-treating the N-vinyl lactam polymer to the base material is known, for applications that require a large surface area such as wallpaper. There was a problem that it was difficult to apply. On the other hand, when the base material is made hydrophilic by kneading with the base material, the N-vinyl lactam polymer has a large torque when kneaded with the polyamide resin, and the obtained polyamide resin composition is There was a problem that it was difficult to mold. Furthermore, since the N-vinyl lactam polymer is easily yellowed by heating, there is also a problem that it is difficult to mold at a high temperature.

  The present invention has been made in view of the above situation, and an object of the present invention is to provide a polyamide resin composition that is easy to overheat and has little yellowing during heating.

The inventors of the present invention have made various studies in order to achieve the above object, and have arrived at the present invention.
That is, the polyamide resin composition of the present invention is a polyamide resin composition containing a polyamide, an N-vinyl lactam polymer, and a monocarboxylic acid, and the content of the monocarboxylic acid (salt) is N -It is 8400-40000 ppm with respect to a vinyl lactam polymer, It is a polyamide resin composition characterized by neutralizing 1-40 mol% of the said monocarboxylic acid (salt) .

The polyamide resin of the present invention can suppress kneading torque and suppress yellowing. Therefore, it can be preferably used as wallpaper for inner walls of residences, commercial facilities, office buildings and the like.

Hereinafter, the present invention will be described in detail.
A combination of two or more preferred embodiments of the present invention described below is also a preferred embodiment of the present invention.
[N-vinyl lactam polymer]
The polyamide resin composition of the present invention contains an N-vinyl lactam polymer as an essential component. In the present invention, the N-vinyl lactam polymer refers to a polymer having a structural unit derived from N-vinyl lactam. Here, the structural unit derived from N-vinyl lactam means a structural unit formed by radical polymerization of N-vinyl lactam. Specifically, the polymerizable carbon-carbon double bond of N-vinyl lactam is carbon. It is a structural unit that is a carbon single bond.

N-vinyl lactam is a monomer having a cyclic lactam ring, for example, N-
Examples include vinylpyrrolidone, N-vinylcaprolactam, and compounds having a structure in which one or more of these hydrogen atoms are substituted with a substituent. Examples of the substituent include an alkyl group having 1 to 20 carbon atoms, an alkyl group having 2 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, and a carboxy ester group having 3 to 20 carbon atoms. And an amino group having 1 to 20 carbon atoms, a hydroxyl group, a carboxylic acid (salt) group, a sulfonic acid (salt) group, a hypophosphorous acid (salt) group, and the like.
Among N-vinyllactams, N-vinylpyrrolidone and / or N-vinylcaprolactam are essential because the polymerizability is good and the color stability of the resulting polymer is good at high temperatures. Is preferred.

  The N-vinyl lactam polymer has structural units derived from monomers other than N-vinyl lactam (hereinafter referred to as “other monomers”) in addition to structural units derived from N-vinyl lactam. You may do it.

  Specific examples of the other monomers include unsaturated acids such as acrylic acid, methacrylic acid, crotonic acid, α-hydroxyacrylic acid, α-hydroxymethylacrylic acid, salts thereof, and derivatives thereof. Monocarboxylic acid-based monomers; unsaturated dicarboxylic acid-based monomers such as itaconic acid, fumaric acid, maleic acid, 2-methyleneglutaric acid, and salts thereof (which may be mono- or di-salts) 3-sulfonic acid monomers such as 3-allyloxy-2-hydroxypropanesulfonic acid, (meth) allylsulfonic acid, isoprenesulfonic acid, vinylsulfonic acid, styrenesulfonic acid and their salts; vinylpyridine, vinylimidazole , Dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, dimethylaminopropyl acrylate, amino ester Amino group-containing monomers such as til methacrylate, diallylamine, diallyldimethylamine, and quaternized compounds and salts thereof; N-vinylformamide, N-vinylacetamide, N-vinyl-N-methylformamide, N-vinyl-N N-vinyl monomers such as methylacetamide and N-vinyloxazolidone; Amide monomers such as (meth) acrylamide, N, N-dimethylacrylamide and N-isopropylacrylamide; 3- (meth) allyloxy-1, Unsaturated alcohol monomers such as 2-dihydroxypropane, 3-allyloxy-1,2-dihydroxypropane, (meth) allyl alcohol, and isoprenol; having a structure in which an alkylene oxide is added to the unsaturated alcohol monomer. Polyalkylene glycol monomer; butyl (Meth) acrylate alkyl ester monomers such as (meth) acrylate, 2-ethylhexyl (meth) acrylate and dodecyl (meth) acrylate; vinylaryl monomers such as styrene, indene and vinylaniline; isobutylene and octene Alkenes; vinyl carboxylates such as vinyl acetate and vinyl propionate; Moreover, said other monomer may be used individually by 1 type, or may use 2 or more types together. Examples of the salt include metal salts, ammonium salts, and organic amine salts.

In the present invention, the structural unit derived from the other monomer is a structural unit formed by polymerization of the other monomer, specifically, the carbon-carbon double bond of the other monomer. Is a structure with a single bond. For example, when the other monomer is butyl acrylate (CH ₂ ═CH ₂ COOC ₄ H ₉ ), the structural unit derived from the other monomer is —CH ₂ —CH ₂ (COOC ₄ H ₉ ). -, Can be represented by

  The N-vinyl lactam polymer is a structural unit derived from all monomers contained in the N-vinyl lactam polymer (a structural unit derived from a structural unit derived from N-vinyl lactam and another monomer). The proportion of the structural unit derived from N-vinyllactam with respect to 100 mol% (mol%) tends to improve compatibility with the polyamide resin and hydrophilicity of the polyamide resin. It is preferably 100 mol% or less, more preferably 80 mol% or more and 100 mol% or less, more preferably 90 mol% or more and 100 mol% or less, and most preferably 100 mol%. preferable.

  The N-vinyl lactam polymer has a proportion (mol%) of structural units derived from other monomers with respect to 100 mol% of structural units derived from all monomers contained in the N-vinyl lactam polymer. 0 mol% or more and 50 mol% or less is preferable, 0 mol% or more and 20 mol% or less is more preferable, 0 mol% or more and 10 mol% or less is more preferable, and 0 mol% or less is more preferable. % Is most preferred.

  When the N-vinyl lactam polymer is a copolymer, each structural unit may be in a block shape, a random shape, or may exist regularly.

  The N-vinyl lactam polymer may contain a structural unit derived from a polymerization initiator or a chain transfer agent. The N-vinyl lactam polymer is a preferred embodiment in which a hypophosphorous acid (salt) group (phosphinic acid (salt) group) is introduced into the main chain. Here, the salt means a metal salt, an ammonium salt, or an organic amine salt. For example, a sodium hypophosphite group (sodium phosphinate group) is represented by -PH (= O) (ONa) or -P (= O) (ONa)-. The hypophosphorous acid (salt) group of the main chain can be introduced into the main chain by using hypophosphorous acid (salt) as a chain transfer agent.

  The N-vinyl lactam polymer preferably has a K value of 10 or more and 90 or less, particularly preferably 20 or more and 60 or less, according to the Fikenture method. If the K value is too high, it becomes difficult to mold a resin composition having a large increase in viscosity during kneading. On the other hand, if the K value is too low, the entanglement of the N-vinyl lactam polymer with the polyamide becomes weak, and elution due to water wetting increases. The K value according to the fixture method can be determined by the following measurement method. When the K value is less than 20, the viscosity of a 5% (g / 100 ml) solution is measured, and when the K value is 20 or more, the viscosity of a 1% (g / 100 ml) solution is measured. Sample concentration is converted to dry matter. When the K value is 20 or more, 1.0 g of the sample is accurately measured, put into a 100 ml volumetric flask, add distilled water at room temperature, dissolve completely with shaking, add distilled water to make exactly 100 ml. To do. This sample solution is allowed to stand for 30 minutes in a thermostatic chamber (25 ± 0.2 ° C.), and then measured using an Ubbelohde viscometer. Measure the time for the solution to flow between the two markings. Measure several times and take the average value. In order to measure relative viscosity, distilled water is measured similarly. The two obtained flow times are corrected based on the Hagenbach-Couette correction.

In the above formula, Z is a relative viscosity (ηrel) of a solution having a concentration C, and C is a concentration (%: g / 100 ml).
The relative viscosity ηrel is obtained by the following equation.
ηrel = (solution flow time) ÷ (water flow time).
The N-vinyl lactam polymer according to the present invention is preferably produced by essentially preparing a step of polymerizing a monomer essentially containing N-vinyl lactam in the presence of a polymerization initiator. -Other monomers may be included in addition to vinyl lactam, but the proportion of N-vinyl lactam used relative to all monomers (N-vinyl lactam and other monomers) is compatible with the polyamide resin. And the hydrophilicity of the polyamide resin tends to be improved, it is preferably 50 mol% or more and 100 mol% or less, more preferably 80 mol% or more and 100 mol% or less, and 90 mol% or more. 100 mol% or less is more preferable, and 100 mol% is most preferable.
The proportion of other monomers used relative to the total monomer is preferably 0 mol% or more and 50 mol% or less, more preferably 0 mol% or more and 20 mol% or less, and more preferably 0 mol% or more. More preferably, it is 10 mol% or less, and most preferably 0 mol%.

The polymerization initiator that can be used in the polymerization step is arbitrary, but it is preferable to use, for example, a water-soluble azo compound or a water-soluble organic peroxide. Moreover, it is preferable that a polymerization initiator does not have a carboxyl group (salt) from a viewpoint of suppressing coloring (yellowing) at the time of a heating as above-mentioned.
Here, the azo polymerization initiator refers to a compound having an azo bond and generating a radical by heat or the like. Examples of water-soluble azo polymerization initiators that can be used in the polymerization step include 2,2′-bis (2-imidazolin-2-yl) [2,2′-azobispropane] dihydrochloride, 2,2 '-Bis (2-imidazolin-2-yl) [2,2'-azobispropane] disulfate, 2,2'-azobis-2-amidinopropane dihydrochloride, 2,2'-azobis [N- (2-carboxyethyl) -2-methylpropionamidine], 2,2′-azobis {2- [1- (2-hydroxyethyl) -2-imidazolin-2-yl] propane} dihydrochloride, 2,2 Examples include '-azobis [2- (2-imidazolin-2-yl) propane], 2,2'-azobis (1-imino-1-pyrrolidino-2-methylpropane) dihydrochloride, and the like.
Among the above azo polymerization initiators, a low molecular weight N-vinyl lactam polymer can be efficiently produced, and the color tone at high temperature of the resulting polymer is good, so that the 10-hour half-temperature is 30. Those having a temperature of not lower than 90 ° C. and not higher than 90 ° C. are preferable, more preferably those having a 10-hour half-life temperature of not lower than 40 ° C. and not higher than 70 ° C.

Water-soluble organic peroxides that can be used in the polymerization step include tertiary butyl hydroperoxide, cumene hydroperoxide, tertiary hexyl hydroperoxide, alkyl hydroperoxide such as p-menthane hydroperoxide, tertiary butyl peroxyacetate, Examples are disuccinoyl peroxide and peracetic acid. Among the above organic peroxides, a low molecular weight N-vinyl lactam polymer can be efficiently produced, and the resulting polymer has good color tone at high temperatures, so that it is an alkyl hydroperoxide. Preferred is tertiary butyl hydroperoxide.
The organic peroxide preferably has a 10-hour half-life temperature of 30 ° C. or more and 180 ° C. or less, and more preferably has a 10-hour half-life temperature of 40 ° C. or more and 170 ° C. or less.

  Examples of the polymerization initiator that can be used in the polymerization step include persulfates such as sodium persulfate, potassium persulfate, and ammonium persulfate, and hydrogen peroxide.

  The amount of the polymerization initiator used in the polymerization step (the total amount when multiple types are used) is 15 g or less, more preferably 0.1 to 12 g, per 1 mol of all monomer components. Is preferred.

In the polymerization step, a chain transfer agent may be used as necessary. Specific examples of chain transfer agents include thiol chain transfer agents such as mercaptoethanol, thioglycolic acid, mercaptopropionic acid, and n-dodecyl mercaptan; halogens such as carbon tetrachloride, methylene chloride, bromoform, and bromotrichloroethane. Secondary alcohols such as isopropanol and glycerin; hypophosphorous acid (salts) such as hypophosphorous acid and sodium hypophosphite (including hydrates thereof); phosphorous acid and sodium phosphite Phosphorous acid (salt) such as sodium sulfite, potassium sulfite and the like; bisulfite (salt) such as sodium hydrogen sulfite and potassium hydrogen sulfite; dithionic acid (salt) such as sodium dithionite; And pyrosulfurous acid (salt) such as potassium sulfite. The chain transfer agent may be used alone or in the form of a mixture of two or more. Among these, hypophosphorous acid (salt) is preferable because the hue of the polyamide resin composition of the present invention during heating is good.
The amount of the chain transfer agent used is preferably 0 g or more and 2 g or less, and preferably 0 g or more and 1 g or less, with respect to 1 mol of the monomer (N-vinyl lactam and other monomers) used. More preferably.

The polymerization step preferably uses a solvent. The solvent preferably contains water, more preferably contains 50% by mass or more and 100% by mass or less, more preferably 80% by mass or more and 100% by mass or less, based on the total amount of the solvent. Solvents usable in the polymerization step include water; lower alcohols such as methanol, ethanol and isopropyl alcohol; lower ketones such as acetone, methyl ethyl ketone and diethyl ketone; ethers such as dimethyl ether and dioxane; amides such as dimethylformaldehyde. Kind. These solvents may be used alone or in the form of a mixture of two or more.
As a usage-amount of a solvent, 40-200 mass% is preferable with respect to 100 mass% of monomers. More preferably, it is 45 mass% or more, More preferably, it is 50 mass% or more. Moreover, More preferably, it is 180 mass% or less, More preferably, it is 150 mass% or less. If the amount of the solvent used is less than 40% by mass, the molecular weight of the resulting polymer may be increased. If it exceeds 200% by mass, the concentration of the obtained polymer will be low, and the cost for storage and the like will be high. There is a risk.

The polymerization in the polymerization step is usually preferably performed at 0 ° C. or higher, and preferably 150 ° C. or lower. More preferably, it is 40 degreeC or more, More preferably, it is 60 degreeC or more, Most preferably, it is 80 degreeC or more. Moreover, More preferably, it is 120 degrees C or less, More preferably, it is 110 degrees C or less.
The polymerization temperature does not necessarily need to be kept almost constant in the polymerization reaction. For example, the polymerization is started from room temperature, the temperature is raised to a set temperature with an appropriate temperature increase time or rate, and then the set temperature is increased. You may make it hold | maintain and you may carry out temperature fluctuation (temperature rise or temperature fall) with time during a polymerization reaction according to dripping methods, such as a monomer component and an initiator.

  The polymerization time in the polymerization step is not particularly limited, but is preferably 30 to 540 minutes, more preferably 45 to 510 minutes, further preferably 60 to 480 minutes, and most preferably 90 to 450 minutes. . In the present invention, “polymerization time” represents the time during which a monomer is added unless otherwise specified.

  The pressure in the reaction system in the polymerization step may be any of normal pressure (atmospheric pressure), reduced pressure, and increased pressure, but in terms of molecular weight of the resulting polymer, the reaction may be performed under normal pressure or reaction. It is preferable to carry out under pressure while the system is sealed. Moreover, it is preferable to carry out under a normal pressure (atmospheric pressure) at the point of equipment, such as a pressurization apparatus, a pressure reduction apparatus, a pressure-resistant reaction container, and piping. The atmosphere in the reaction system may be an air atmosphere or an inert atmosphere. For example, the inside of the system may be replaced with an inert gas such as nitrogen before the start of polymerization.

  The N-vinyl lactam polymer is optional, but may be produced including steps other than the polymerization step. Examples include an aging step, a pH adjustment step, a polymerization initiator and chain transfer agent deactivation step, a dilution step, a drying step, a concentration step, and a purification step.

[Monocarboxylic acid (salt)]
The polyamide resin composition of the present invention contains a monocarboxylic acid (salt) as an essential component. By including the monocarboxylic acid (salt), the kneading torque of the polyamide resin composition of the present invention tends to decrease as described later. The monocarboxylic acid (salt) is a compound having one carboxylic acid (salt) group in the molecule.
Examples of the monocarboxylic acid (salt) include formic acid, acetic acid, propionic acid, butyric acid, and salts thereof. Saturated fatty acids are preferred because of the high effect of improving color tone at high temperatures, formic acid, acetic acid, propionic acid, butyric acid, and salts thereof are more preferred, and formic acid and acetic acid are particularly preferred.

The monocarboxylic acid (salt) also tends to suppress yellowing during overheating of the polyamide resin composition of the present invention, so that 1 to 40 mol% of the monocarboxylic acid (salt) is neutralized. Has been . More preferably, 3 to 30 mol% is neutralized. When the neutralization rate is higher than the above range, the polyamide resin composition at the time of kneading tends to thicken and the torque tends to increase.
When neutralized, the monocarboxylic acid (salt) is preferably a lithium salt, sodium salt, potassium salt, ammonium salt, or organic amine salt of a monocarboxylic acid, and is a sodium salt or potassium salt. Is more preferable.

[Polyamide resin]
The polyamide resin composition of the present invention contains a polyamide resin as an essential component. A polyamide resin is a polymer containing an amide bond (—CO—NH) in the main chain structure of a repeating unit.
For example, a polymer obtained by (co) polycondensation reaction of a lactam having 6 to 20 carbon atoms, a diamine having 4 to 20 carbon atoms, a dicarboxylic acid having 6 to 20 carbon atoms, a dicarboxylic acid ester, and a dicarboxylic acid chloride. Examples of the polymer obtained by the copolycondensation reaction include nylon 6, nylon 11, nylon 12, nylon 66, nylon 46, nylon 610, and the like. The polyamide resin also includes an aramid resin.
As the polyamide resin, nylon 6 is preferable from the viewpoint of melting point.
[Polyamide resin composition of the present invention]
The polyamide resin composition of the present invention includes the N-vinyl lactam polymer, the monocarboxylic acid (salt), and the polyamide resin. The polyamide resin composition of the present invention is a total of the N-vinyl lactam polymer, the monocarboxylic acid (salt), and the polyamide resin, with respect to 100% by mass of the polyamide resin composition of the present invention. 50 mass% or more and 100 mass% or less are included. Preferably, 80 mass% or more and 100 mass% or less are included, More preferably, 90 mass% or more and 100 mass% or less are included.

  The polyamide resin composition of the present invention preferably contains the N-vinyl lactam polymer and the polyamide resin in a mass ratio of 0.5: 99.5 to 50:50, and 1:99 to 40: 60 is more preferable, and 3:97 to 30:70 is more preferable. By including in the said range, it exists in the tendency for the kneading | mixing torque of the polyamide resin composition of this invention to fall.

The polyamide resin composition of the present invention contains 0.84 % by mass or more and 4% by mass or less of the monocarboxylic acid (salt) with respect to 100% by mass of the N-vinyl lactam polymer . Preferably they are 0.84 mass% or more and 3 mass% or less, More preferably, they are 0.84 mass% or more and 2 mass% or less. By including in the said range, it exists in the tendency for the kneading | mixing torque of the polyamide resin composition of this invention to fall.
In addition, in calculation of content of said monocarboxylic acid (salt), monocarboxylic acid (salt) calculates content as an acid type. “Calculating as the acid type” means, for example, when the monocarboxylate is sodium formate, calculating the mass as the corresponding acid, formic acid.

  The polyamide resin composition of the present invention contains a polyamide resin, an N-vinyl lactam polymer, and a monocarboxylic acid (salt) as essential components, and may contain various additives as desired. Further, it may contain a reducing compound such as hypophosphorous acid (salt), a pH adjuster such as caustic soda, and the like.

[Method for Producing Polyamide Resin Composition of the Present Invention]
The polyamide resin composition of the present invention includes a step of mixing a polyamide resin, an N-vinyl lactam polymer, and a monocarboxylic acid (salt) (hereinafter also referred to as “mixing step”).
As a mixing method in the mixing step, a method of kneading a molten polyamide resin with an N-vinyl lactam polymer and a monocarboxylic acid (salt) is preferable.
When kneading an N-vinyl lactam polymer and a monocarboxylic acid (salt) into a molten polyamide resin, the N-vinyl lactam polymer and the monocarboxylic acid (salt) may be added separately. The N-vinyl lactam polymer and the monocarboxylic acid (salt) may be mixed in advance and then added to the melted polyamide resin.
In the case where the N-vinyl lactam polymer and the monocarboxylic acid (salt) are added separately, the N-vinyl lactam polymer and the monocarboxylic acid (salt) are separately added to the melted polyamide resin. A method of kneading simultaneously, a method of adding and kneading a monocarboxylic acid (salt) to the first melted polyamide resin, and then adding and kneading an N-vinyl lactam polymer are exemplified.
Kneading a polyamide resin and an N-vinyl lactam polymer in the presence of a monocarboxylic acid (salt) is preferable because the kneading torque is reduced.
In addition, when adjusting the neutralization rate of the monocarboxylic acid (salt), a predetermined amount of acid-type monocarboxylic acid and salt-type monocarboxylic acid salt may be used. And a predetermined amount of an alkali compound may be used. Examples of the alkali compound include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide; alkali metal carbonates such as sodium carbonate, potassium carbonate and sodium bicarbonate; ammonia; organic amines such as monoethanolamine and diethanolamine. And the like are exemplified.

[Use of the polyamide resin composition of the present invention]
As described above, the polyamide resin composition of the present invention can be preferably used as wallpaper for interior walls of residences, commercial facilities, office buildings, etc., but in addition, various film raw materials for packaging, agriculture, etc. It can be preferably used as various fiber raw materials for clothing, carpets, fishing lines and the like.

The present invention will be described in more detail with reference to examples below, but the present invention is not limited to these examples. Unless otherwise specified, “part” means “part by mass” and “%” means “% by mass”.
<Polymer aqueous solution, method for measuring solid content of polymer composition>
Under a nitrogen atmosphere, 2.0 g of the polymer composition was allowed to stand for 1 hour in an oven heated to 150 ° C. and dried. From the mass change before and after drying, the solid content (%) and the volatile component (%) were calculated.

<Analysis of monomer>
The monomer was analyzed using liquid chromatography under the following conditions.
Equipment: Shiseido “NANOSPACESI-2”
Column: Shiseido “CAPCELLLPAK C18 UG120”, 20 ° C.
Eluent: LC methanol (manufactured by Wako Pure Chemical Industries, Ltd.) / Ultra pure water = 1/24 (mass ratio),
Addition flow rate of sodium 1-heptanesulfonate 0.4% by mass: 100 μL / min.

<Measurement of molecular weight of polymer>
It measured by the measuring method of said K value.

<Acid content measurement (ion chromatography analysis)>
The acid content was measured by ion chromatography analysis under the following conditions.
Apparatus: 762 Interface manufactured by Metrohm
Detector: 732 IC Detector manufactured by Metrohm
Ion analysis method: Suppressor method Column: Shodex IC SI-90 4E
Guard column: Shodex SI-90 G
Column temperature: 40 ° C
Eluent: NaHCO3 water (2 g diluted to 2000 g with water)
Flow rate: 1.2 mL / min.

<Production Example 1>
Polymerization process:
In a SUS reaction vessel equipped with a Max blend (registered trademark of Sumitomo Heavy Industries, Ltd.) type stirring blade, glass lid, stirrer with stirring seal, nitrogen introduction tube, and temperature sensor, ion-exchanged water (420. 4 parts by weight) 1.5% by weight of a 5% aqueous sodium hydroxide solution (hereinafter referred to as “5% NaOHaq”), sodium diphosphite monohydrate (manufactured by Wako Pure Chemical Industries, Ltd., hereinafter “SHP. 2.5 mass parts) (denoted as “1H ₂ O”), and the mixture was stirred at 200 rpm under a nitrogen stream and heated to 90 ° C.
As a monomer aqueous solution, a solution was prepared by adding 55.6 parts by mass of ion-exchanged water to 500 parts by mass of N-vinylpyrrolidone (hereinafter referred to as “NVP”).
As an aqueous initiator solution, 2,2′-azobis-2-amidinopropane dihydrochloride (manufactured by Wako Pure Chemical Industries, Ltd., hereinafter referred to as “V-50”) is added to 3.0 parts by mass of ion-exchanged water 17.0 parts by mass. A solution was added.
Nitrogen was introduced at 30 mL / min, and the monomer aqueous solution prepared above was continuously added dropwise for 360 minutes while maintaining the temperature at 90 ± 2 ° C. Moreover, the initiator aqueous solution was dripped continuously for 390 minutes. The polymerization reaction was completed by maintaining at 90 ° C. for 30 minutes after completion of the dropping.
Furthermore, an aqueous solution of polymer (1) was obtained by adding 8.4 parts by mass of an 88% aqueous formic acid solution (manufactured by Wako Pure Chemical Industries, Ltd.) 420 minutes after the start of polymerization.
Drying and grinding process:
The obtained aqueous solution was put into a drum dryer and dried for 20 seconds under the operating conditions of a drum surface temperature of 140 ° C. and a drum rotation number of 1.5 rpm, and the resulting dried product was pulverized with a lab miller to obtain a polymer (1). Of powder was obtained.

<Example 1>
Nylon 6 (trade name; Amilan CM1017, hereinafter referred to as “PA”) as polyamide, 24 parts, and 6 parts of the polymer (1) powder obtained in the above process can be measured for torque. A polyamide resin composition of the present invention was obtained by melt kneading at 240 ° C. for 5 minutes using a simple Laboplast mill (Toyo Seiki Co., Ltd., 4C150). The value at the end of 5 minutes was used as the torque value.
The color of the resin composition taken out was determined visually.
A: Remarkably white.
○ ... White.
Δ: Slightly yellowish.
X: Yellow.

<Examples 2 and 3 and Comparative Examples 1 and 2>
The torque value and hue were evaluated in the same manner as in Example 1 except that the type, addition amount, and neutralization rate of the monocarboxylic acid (salt) were changed as shown in Table 1. The evaluation results are summarized in Table 1.
“PVP” in Table 1 represents polyvinylpyrrolidone, and “content (ppm / PVP)” of monocarboxylic acid (salt) in Table 1 is included in the polyamide resin composition after melt-kneading. The amount of monocarboxylic acid (salt) to be obtained is shown by mass with respect to PVP contained in the polyamide resin composition.

From the results shown in Table 1, the polyamide resin composition of the present invention has a good overheat moldability because it has a low torque during good kneading, and can maintain a good hue even when heated. It was revealed.

Claims (3)

A polyamide resin composition comprising polyamide, an N-vinyl lactam polymer, and a monocarboxylic acid (salt) , wherein the content of the monocarboxylic acid (salt) is relative to the N-vinyl lactam polymer. A polyamide resin composition characterized by being 8400 to 40,000 ppm, wherein 1 to 40 mol% of the monocarboxylic acid (salt) is neutralized . The polyamide resin composition according to claim 1, wherein the monocarboxylic acid (salt) is at least one selected from the group consisting of formic acid, acetic acid, propionic acid, butyric acid, and salts thereof. . Characterized in that 27.6 to 40 mol% of the previous SL monocarboxylic acid (salt) is neutralized, the polyamide resin composition according to claim 1 or 2.