JP3003202B2 - Method for producing polyamide resin-based masterbatch - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing a masterbatch of a metaxylylene group-containing polyamide resin used for various molded articles as a polyamide resin. More specifically, the present invention relates to a method for producing a polyamide resin-based masterbatch in which an organic metal salt containing crystallization water is melt-mixed with a metaxylylene group-containing polyamide resin.

(Prior art) Conventionally, a meta-xylylene group-containing polyamide resin (hereinafter referred to as
MX nylon) is used for films, sheets, injection molded products, hollow containers, etc. because of its excellent properties such as mechanical strength, formability, chemical resistance, etc. As a method of coloring, (A) a method in which a required amount of a colorant (less than 1 part by weight) is directly applied to a resin pellet and mixed and then applied to a molding machine; (Less than 1 part by weight), and the mixture is melt-mixed with an extruder, pelletized, and then subjected to a method in a molding machine. (C) A method of using a part of the resin to be used or a resin of the same system (usually called natural) to obtain a high concentration ( (1 part by weight or more) in which a colorant is melt-mixed and dispersed to prepare a pellet (master batch), which is naturally diluted to a required concentration and then applied to a molding machine.

However, in the method (A), a molded article having a good uniform dispersion of the colorant cannot be obtained, and there is inconvenience in the production of molded articles such as problems in handling, stains of a molding machine, and color change. There is a disadvantage that. Next, in the method (B), although there is no problem in dispersibility of the colorant and handling, the production cost is increased because a process of once melting and mixing the entire amount used in the molding with an extruder is included.
Even in the performance of the final molded article, the entire amount is once subjected to a thermal history of being in a molten state, so that the molecular weight of the resin itself is reduced, and the strength and durability of the molded article are reduced. In the method (C),
A masterbatch in which the colorant is melted, mixed and dispersed in a high concentration (1 part by weight or more) in advance, is diluted to the required concentration naturally, and is applied to a molding machine. There is no problem with the dispersibility of the colorant and handling. In addition, since only the master batch has a thermal history of being in a molten state, the performance of the molded article is not greatly reduced. However, when an attempt is made to produce a masterbatch using an organometallic salt containing water of crystallization which is industrially generally produced and inexpensive in the present invention, a significant decrease in molecular weight occurs,
The melt viscosity is also remarkably reduced, so that casting pellets cannot be formed, and production is practically impossible.

(Problems to be Solved by the Invention) An object of the present invention is to use it for molded products such as films, sheets, injection molded products, and hollow containers because of its excellent properties of mechanical strength, moldability, and chemical resistance. An object of the present invention is to provide a method for producing a polyamide resin-based masterbatch in which an inexpensive organic metal salt containing crystallization water is melt-mixed with MX nylon, which is generally produced industrially and inexpensively.

(Means for Solving the Problems) The present invention pays attention to such problems, and as a result of earnest studies on a method for producing a polyamide resin masterbatch free of the above-mentioned drawbacks, a polyamide resin-based masterbatch capable of improving the above drawbacks Of the present invention and arrived at the present invention.

That is, according to the present invention, when a masterbatch is produced by melting and mixing 1 to 3 parts by weight of an organic metal salt containing water of crystallization with a metaxylylene group-containing polyamide resin, a condition that can satisfy the following (1) and (2) is satisfied. And a method of producing a polyamide resin-based masterbatch.

(1) The condition that the residence time in the extruder is in the range of 255 to 285 ° C. in the extruder; R (seconds) is in the range of the following formula (where T is the melting temperature ° C.): 15 ≦ R ≦ 45 + (285−T) /0.25 ( 2) Removal of water generated during melting from the barrel vent of the extruder MX nylon in the present invention refers to metaxylylenediamine alone or metaxylylenediamine and the total amount of metaxylylenediamine.
It means a polymer containing at least 70 mol% or more of a constitutional unit obtained from xylylenediamine containing 30% or less of paraxylenediamine and α · ω-aliphatic dicarboxylic acid having 6 to 10 carbon atoms.

Examples of these polymers include homopolymers such as polymetaxylylenediadipamide, polymetaxylylenesepacamide, polymetaxylylenesperamide, etc., metaxylylene / paraxylylene adipamide copolymer, metaxylylene / Paraxylylenepimelamide copolymer, copolymers such as metaxylylene / paraxylylene apyramide copolymer and components of these homopolymers or copolymers, and aliphatic diamines such as hexamethylenediamine, piperazine Alicyclic diamines such as para-bis- (2-aminoethyl) benzene, aromatic dicarboxylic acids such as terephthalic acid, lactams such as ε-caprolactam, and ω-aminoheptanoic acid. Like ω-
Copolymers with aromatic aminocarboxylic acids such as aminocarboxylic acid and para-aminobenzoic acid can be exemplified.

In addition, for example, nylon 6, nylon
A polymer such as 66, nylon 10, nylon 11, etc. may be contained, and if necessary, an ultraviolet absorber, an antistatic agent and the like may be blended within a range not to impair the object of the present invention.

The relative viscosity of these MX nylons is suitably 1.5 or more, and preferably 2.0 or more.

The organic metal salt in the present invention is an organic metal salt containing water of crystallization, and examples thereof include ferrous oxalate dihydrate, cobalt acetate tetrahydrate, and nickel acetate tetrahydrate.

In the present invention, to prepare a master batch by melt mixing 1 to 3 parts by weight of an organic metal salt containing crystallization water with MX nylon using an extruder, first, an organic metal salt containing MX nylon and water of crystallization The temperature of melt mixing of 255 ~ 2
85 ° C, preferably 260-280 ° C. If the temperature is lower than 255 ° C., mixing becomes difficult because the viscosity of the polymer becomes high.
When the temperature exceeds ℃, the decomposition of nylon, particularly the influence of the organic metal salt containing water of crystallization becomes remarkably large, so it is necessary to adopt the above temperature range. Next, the melt mixing time, that is, the residence time in the extruder; R [seconds] is 15 ≦ R ≦ 45 + (285−
T) /0.25 (where T is the melting temperature ° C), preferably 15 ≦
R ≦ 15 + (285 −) / 0.25. If the above formula is not satisfied, it is difficult to melt and mix MX nylon and the organic metal salt containing water of crystallization, excessive load is applied to the extruder screw, and the effect of the organic metal salt containing water of crystallization becomes remarkable. The molecular weight of MX nylon decreases. Further, when the water of crystallization contained in the organic metal salt is melted, it becomes water and acts to reduce the molecular weight of the MX nylon, resulting in a phenomenon of foaming. Therefore, it is necessary to remove the water generated during melting from the barrel vent of the extruder in order to suppress the effect of the generated water. Or, more preferably, it is necessary to apply a vacuum from the vent port to actively remove water. Also,
The amount of the organic metal salt containing crystallization water to be melt-mixed is 3 parts by weight or less, preferably 2.5 parts by weight or less. If the amount exceeds 3 parts by weight, the effect of water due to the crystallization water cannot be completely suppressed, and foaming tends to occur. If the amount is less than 1 part by weight, the cost advantage of forming a master batch is lost.

Therefore, when melt-mixing 1 to 3 parts by weight of an organic metal salt containing water of crystallization with MX nylon to produce a master batch, the following (1) and (2) are used using an extruder.
It is necessary to carry out melt mixing under conditions that can satisfy the following conditions.

(1) The condition that the residence time in the extruder is in the range of 255 to 285 ° C. in the extruder; R (seconds) is in the range of the following formula (where T is the melting temperature ° C.): 15 ≦ R ≦ 45 + (285−T) /0.25 ( 2) Removal of water generated during melting from the barrel vent of the extruder. The residence time in the extruder as used herein refers to the time taken for the extruder to pass from the material input port to the nozzle outlet. A single-screw extruder generally used in industry, preferably a twin-screw extruder.

In the present manufacturing method for producing a master batch by melting and mixing 1 to 3 parts by weight of an organic metal salt containing water of crystallization with MX nylon, 1 to 3 parts by weight of an organic metal salt containing water of crystallization in MX nylon is used. Despite being mixed
Since the melt viscosity of the melt mixture does not significantly decrease and the foaming state is suppressed, a masterbatch can be manufactured, and the production method of the present invention can provide a practical masterbatch with a small decrease in molecular weight.

(Examples) Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

 First, the main methods of measuring physical properties are as follows.

(1) Relative viscosity of polyamide resin (RV) Relative viscosity measured at 25 ° C using 96% sulfuric acid solvent (2) Reduced viscosity of master batch (ηsp / c) Phenol / tetrachloroethane = 6/4 (weight ratio) (3) Color b value of master batch pellets (Co-b
Value) Measured by Tokyo Denshoku Co., Ltd. Color Analyzer Next, the used MX nylon and the organic metal salt containing water of crystallization are as follows.

(1) MX nylon Toyobo Co., Ltd. RV = 2.1 metaxylylene group-containing polyamide resin (2) Organic metal salt containing water of crystallization Wako Pure Chemical Industries, Ltd. Cobalt acetate tetrahydrate Shula, Nacalai Tesque, Ltd. Ferrous acid dihydrate Examples 1 to 5 and Comparative examples 1 to 4 Using the above-mentioned MX nylon and the organic metal salt containing water of crystallization, polyamide was produced using a 45φ biaxial extruder manufactured by Ikegai Iron Works Co., Ltd. Production of a resin masterbatch was performed. Table 1 shows the evaluation results of the production status. In Table 1, Ac represents cobalt acetate tetrahydrate, Nf represents ferrous oxalate dihydrate, T represents the melting temperature, and R represents the residence time in the extruder.

As is clear from Table 1, the production method of the present invention enables production of a masterbatch.

Table 2 shows the evaluation results of the reduced viscosity (ηsp / c) and the color b value (Co-b value) of the polyamide resin master batch obtained under the production conditions in Table 1. (However, in the measurement of the color b value, since master batches under the manufacturing conditions of Comparative Examples 2 to 4 could not be manufactured in a pellet shape, a sample cut into a pellet shape measurable with a nipper was used.) As is clear from Table 2, the reduced viscosity (ηsp / c) in the masterbatch method obtained by the production method of the present invention was used.
And a masterbatch with less fading even in the color b value (Co-b value) can be obtained.

(Effect of the Invention) The method for producing a polyamide resin masterbatch according to the present invention enables stable industrial production of a polyamide resin masterbatch, and provides a polyamide resin masterbatch with a reduced molecular weight and less fading.

────────────────────────────────────────────────── (5) References JP-A-49-99355 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08J 3/00-3/28 C08L 1 / 00-101/14

Claims (1)

(57) [Claims] 1. A process for melting and mixing 1 to 3 parts by weight of an organic metal salt containing water of crystallization with a meta-xylylene group-containing polyamide resin to produce a masterbatch under conditions that can satisfy the following (1) and (2): A method for producing a polyamide resin-based master batch, comprising: (1) The condition that the residence time in the extruder is in the range of 255 to 285 ° C. in the extruder; R (seconds) is in the range of the following formula (where T is the melting temperature ° C.) 15 ≦ R ≦ 45 + (285−T) /0.25 2) Removal of water generated during melting from the barrel vent of the extruder