JP2001081189A - Nylon-6 or its copolymer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a nylon-6 copolymer low in production of ε-caprolactam in melt spinning, melt process, film forming or the like, excellent in heat stability, useful for high quality fibers and films or the like by formulating a specific piperidone compound to monomer raw material in polymerization. SOLUTION: One or more kind of piperidone compounds expressed by formula (R is H, a 1-18C alkyl or benzyl) (e.g. 2,2,6,6-tetramethylpiperidone or the like) are existing in the polymer chain or ends in a chemically bonded state. The objective copolymer is preferably obtained by polymerizing E-caprolactam or 6-aminocaproic acid as the main component in the presence of the piperidone compound, combining with polymerization initiator such as water or the like, a chain transfer controlling agent or the like such as acetic acid or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to nylon 6 or a copolymer thereof having improved operation stability. More specifically, ε- at the time of melt spinning, melt molding, film formation, etc.
Nylon 6 with low caprolactam production, good thermal stability and high quality fibers and films
Or a copolymer thereof and a method for producing the same.

[0002]

2. Description of the Related Art Nylon 6 resin is a versatile engineering plastic excellent in mechanical strength, heat resistance, chemical resistance, workability, etc., and is used in automobiles and home appliances, including tire cords, clothing and packaging films. Widely used as parts of office equipment.

However, the stability of the nylon 6 resin, such as the weather resistance of the nylon 6 resin, that is, the high temperature resistance when exposed to a high temperature in the presence of oxygen and humidity, the thermal stability and the viscosity stability at a high temperature, etc. The properties are not sufficient for various applications. For example, coloring occurs during thermal processing of various fiber products. Similar problems also occur in films and injection molded products. Furthermore, for example, when melt-spinning into fibers, if melt extrusion is performed for a long time, monomers and oligomers are regenerated, accumulate around the discharge hole of the die, and eventually heat denature around the discharge hole, The yarn is deformed around the discharge hole, and yarn breakage or yarn unevenness occurs. Further, when producing a film, there is a problem that the quality is reduced because monomers and oligomers are regenerated when the chips are melted.

[0004] Therefore, various methods have heretofore been attempted to solve these problems, but a method of blending a specific inorganic compound into a nylon 6 resin is generally used. For example, a nylon 6 resin composition containing magnesium oxide (Japanese Patent Publication No. 55-20007) or a nylon 6 resin containing a specific amount of magnesium oxide fine particles having a specific crystal structure.
Resin compositions (JP-B-55-27172) have been proposed. However, these inorganic compounds are solid powders at the melting temperature of the nylon 6 resin, and if spinning is performed for a long time, the nozzle pressure will increase, causing a problem in operation. Further, when these are added in large amounts, there arises a problem that the quality of the product is deteriorated such as spinning stability and yarn unevenness.

[0005] On the other hand, as a method for reducing the amount of regenerated ε-caprolactam and oligomers during melt molding, various attempts have been made to end-block nylon 6 molecular chains. For example, there is a method in which a small amount of a monocarboxylic acid such as acetic acid or benzoic acid or a dicarboxylic acid such as terephthalic acid or adipic acid is used in combination during the polymerization of nylon 6 resin. Further, a method of blocking the terminal of a carboxyl group with a specific amount of a monoamino hydrocarbon (JP-A-62-252424) and a method of blocking the terminal of a carboxyl group with cyclohexylamine or the like (JP-A-8-2317)
No. 11). However, these methods can reduce the regeneration of ε-caprolactam and oligomers during the melt molding of nylon 6 resin, but it is difficult to obtain those having a high degree of polymerization, and various molded articles using these are difficult to obtain. There is a problem that physical properties deteriorate. Also,
It is not sufficient in terms of improving weather resistance and thermal stability.

Accordingly, Japanese Patent Application Laid-Open No. 10-504046 discloses the following formula.

Embedded image Wherein R is a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms, particularly an amine group substituted with an alkyl group or benzyl group having 1 to 18 carbon atoms, is chemically bonded to the polymer chain. Substantially light-stabilized, heat-stabilized polyamides are disclosed. JP-A-10-120781 discloses that polymerization or polycondensation of a polyamide-forming monomer is carried out by using a 4-amino-2,2,6,6-tetraalkylpiperidine, a primary amino group and a tertiary amino group. A method for improving the weather resistance of a polyamide by carrying out in the presence of an aliphatic or alicyclic diamine having the formula (1) and a 2,6-dialkylphenol having a hydroxyl group at the 4-position is disclosed. However, there is a problem that the end-capping agent used in the method described here is costly.

[0007]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems and has a small amount of ε-caprolactam produced during melt spinning, melt molding, film formation, etc., has good thermal stability, and has high quality. It is intended to provide nylon 6 or a copolymer thereof, which can be used as a fiber or film.

[0008]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, it has been found that this object can be achieved by adding a specific piperidone compound to a monomer material during polymerization. And arrived at the present invention.

That is, the gist of the present invention is as follows. (1) At least one piperidone compound represented by the following formula is present in a state of being chemically bonded to a polymer chain or at a terminal. Nylon 6 characterized by having
Or a copolymer thereof.

Embedded image (2) A method for producing nylon 6 or a copolymer thereof, wherein ε-caprolactam or 6-aminocaproic acid is polymerized as a main component in the presence of at least one piperidone compound represented by the above formula. .

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.

The nylon 6 or a copolymer thereof according to the present invention comprises:
It is necessary that at least one piperidone compound represented by the above formula is present in the polymer chain or at a terminal in a chemically bonded state, and the caproamide unit as a main component is 80 mol% or more. , Preferably 90 mol%
It is contained in the above proportions.

Here, the presence of the compound in a chemically bonded state specifically means the following formula:

Embedded image The imino bond and / or the amide bond represented by the following formula is contained in the polymer chain or at the terminal.

The nylon 6 copolymer means less than 20 mol% of ε-caprolactam or 6-aminocaproic acid forming caproamide units and other various lactams, aminocarboxylic acids and nylon salts, preferably less than 20 mol%. It is obtained by copolymerizing at a ratio of less than 10 mol%.

Specific examples of the above-mentioned copolymer component include ω-
Laurolactam, 11-aminoundecanoic acid, 12-aminododecanoic acid, p-aminomethylbenzoic acid, nylon 46
Salt, nylon 66 salt, nylon 610 salt, nylon 612 salt,
Nylon 6T salt, Nylon 6I salt, Nylon 9T salt, Salt of meta-xylylenediamine with adipic acid (Nylon MXD salt)
And the like.

The relative viscosity of the nylon 6 of the present invention or its copolymer is determined by using 97% by weight of concentrated sulfuric acid as a solvent at a temperature of 25%.
It is preferably in the range of 1.5 to 5.0, more preferably in the range of 2.0 to 3.0, at a temperature of 1 ° C. and a concentration of 1 g / dl. If the relative viscosity is less than 1.5, the mechanical strength of the fiber or film decreases. Conversely, if it exceeds 5.0, the moldability decreases rapidly.

Next, a method for producing the nylon 6 or a copolymer thereof according to the present invention will be described. That is, in the method of the present invention, in the presence of at least one piperidone compound represented by the above formula, ε-
It is necessary to polymerize caprolactam or 6-aminocaproic acid.

Specific examples of the piperidone-based compound represented by the above formula include 2,2,6,6-tetramethylpiperidone and N-
Methyl-2,2,6,6-tetramethylpiperidone, N-benzyl
-2,2,6,6-tetramethylpiperidone and the like,
6,6-Tetramethylpiperidone is preferred.

The piperidone compound is added to the starting monomer material or the polymerization reaction mixture, and is bonded to the polymer chain or at the terminal by the reaction represented by the above formula.

The polymerization of the starting monomer material in the presence of at least one piperidone compound represented by the above formula is carried out by a conventional batch method or a continuous method using a polymerization initiator. At this time, at least one kind of the piperidone-based compound, the polymerization initiator, and the starting monomer material are introduced into the reactor separately or as a mixture, and then subjected to polymerization.

At this time, the piperidone compound is preferably added in the range of 0.001 to 0.008 mol per 1 mol of ε-caprolactam or 6-aminocaproic acid as the main component. If the addition amount is less than 0.001 mol, satisfactory thermal stabilization cannot be obtained, and if it exceeds 0.008 mol, the molar balance between the amino group and the carboxyl group of the raw material is disrupted, and a desired polymerization degree cannot be obtained. .

As the polymerization initiator, water, 6-aminocaproic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid, p-aminobenzoic acid and the like are used, but water is preferred.

Further, in the method of the present invention, the piperidone-based compound can be used in combination with other conventional chain regulators. Specific examples of this chain control agent include:
Acetic acid, propionic acid, monocarboxylic acids such as benzoic acid, adipic acid, azelaic acid, sebacic acid, alkane dicarboxylic acids such as dodecane diacid, cycloalkane dicarboxylic acids such as cyclohexane-1,4-dicarboxylic acid, isophthalic acid, And aromatic dicarboxylic acids such as terephthalic acid and naphthalene-2,6-dicarboxylic acid. The type and amount of the chain control agent are determined by the desired amino terminal group concentration (or carboxyl terminal group concentration) and the desired melt viscosity stability as the final product.

The polyamide 6 or the copolymer thereof according to the present invention may contain, if necessary, a heat stabilizer, a weathering agent, an inorganic filler, a reinforcing agent, an antioxidant, and an impact resistance as long as its physical properties are not impaired. Materials, plasticizers, pigments, brighteners, lubricants, flame retardants and the like may be added, and these are added during polymerization, dry blending, melt kneading or melt molding.

[0024]

The reason why the heat stabilization of the polyamide 6 or the copolymer thereof of the present invention can be expected during the melt spinning, the film forming process, the molding process, and the like is that a specific piperidone compound is being formed by polymerization. It is presumed that it reacts with the amino group or carboxyl group of the polymer and is chemically bonded in the polymer chain or at the terminal to reduce the amino terminal group concentration or carboxyl terminal group concentration. Therefore, the polyamide 6 or a copolymer thereof of the present invention hardly regenerates low-molecular compounds such as ε-caprolactam and oligomer during melt molding, and the operation stability is improved.

[0025]

Next, the present invention will be described more specifically with reference to examples. In addition, the measuring method of the raw material and physical property test used in the Examples and Comparative Examples is as follows. 1. Ingredients-ε-caprolactam: Ube Industries, Ltd.-2,2,6,6-tetramethylpiperidone monohydrate: Tokyo Kasei Co., Ltd.-Nylon 66 salt: BASF Co., Ltd.-12-aminododecanoic acid: Nakarai Tesque Made 2. Measurement method (a) Relative viscosity Prepare 97% sulfuric acid as a solvent to a concentration of 1 g / dl.
It measured at 25 degreeC using the Ubbelohde viscometer. (b) Melt viscosity stability A pellet of polyamide 6 or a copolymer thereof prepared to a water content of 0.02% by weight or less is freeze-ground in liquid nitrogen and melted in a glass tube at 0.01 Torr or less at 250 ° C. for 5 hours, The relative viscosity before and after that was measured by the method described in (a), and the increase was used as an index of melt viscosity stability. The smaller the value, the better the thermal stability. (c) Amino end group concentration 0.5 g of nylon 6 or a copolymer thereof prepared to a water content of 0.02% by weight or less and 20 ml of m-cresol were put in a flask, dissolved at 60 ° C, and cooled to room temperature. 0.1
It was determined by performing titration with an aqueous solution of p-toluenesulfonic acid of N. (d) Carboxyl end group concentration 0.2 g of nylon 6 or a copolymer thereof prepared to have a water content of 0.02% by weight or less and 0.2 ml of benzyl alcohol were placed in a flask, and dissolved at room temperature. It was determined by performing a titration with a benzyl alcohol solution. (e) Detected amount of ε-caprolactam Pellets of nylon 6 or a copolymer thereof prepared to a water content of 0.02% by weight or less were melted at 250 ° C. at 0.01 Torr or less for 5 hours, and then freeze-ground in liquid nitrogen. Then, 0.5 g of the ground material was dispersed in 10 ml of distilled water, extracted with hot water at 100 ° C. for 5 hours, and filtered with a filter having a pore size of 0.45 μm as a measurement sample. A high-performance liquid chromatograph (600E, manufactured by Waters Inc.) ) Was used to quantify the amount of ε-caprolactam in the extraction water. The high-performance liquid chromatograph measurement was performed under the following conditions. Column: C ₁₈ (Waters, 250 mm long, inside diameter
4.6mm) Eluent: methanol / water = 35/65 (volume ratio) Flow rate: 0.7ml / min Column temperature: room temperature Detector: UV 210nm

EXAMPLE 1 10.0 kg of ε-caprolactam, 1 kg of water and 38 g of 2,2,6,6-tetramethylpiperidone (corresponding to 0.0028 mol per mol of ε-caprolactam) in a 30 liter reactor The mixture was heated to 260 ° C. while stirring, and the pressure was increased to 5 kg / cm ² . Thereafter, the pressure was released to normal pressure, and polymerization was carried out at 260 ° C. for 3 hours. At the time of completion of the polymerization, the reaction product was discharged in a strand form, cooled, solidified, and cut to obtain nylon 6 pellets. Next, the pellets were treated with hot water at 95 ° C. for refining, and dried at 100 ° C. for 12 hours under a nitrogen atmosphere to adjust the water content to 0.02% by weight or less. Various physical properties tests were performed using the nylon 6 pellets (or crushed products) obtained by the above method. Table 1 shows the obtained results.

Example 2 The raw materials were charged with 9.0 kg of ε-caprolactam, 1.0 kg of 12-aminododecanoic acid, 1 kg of water and 38 g of 2,2,6,6-tetramethylpiperidone (0 mol per mol of ε-caprolactam). .
0025 moles. ), Polymerization, refining and drying were carried out under the same conditions as in Example 1 to obtain nylon 6/12 pellets. Various physical property tests were performed using the nylon 6/12 pellets (or crushed products) thus obtained. Table 1 shows the obtained results.

Example 3 Raw materials were charged with ε-caprolactam 9.5 kg, nylon 66
Polymerization was carried out under the same conditions as in Example 1 except that 0.5 kg of salt, 1 kg of water and 38 g of 2,2,6,6-tetramethylpiperidone were used (corresponding to 0.0027 mol per mol of ε-caprolactam). , Refining and drying to obtain nylon 6/66 pellets. Various properties tests were performed using the nylon 6/66 pellets (or crushed products) obtained in this manner.
Table 1 shows the obtained results.

Example 4 The amount of 2,2,6,6-tetramethylpiperidone was increased from 38 g.
Polymerization, refining and drying were carried out under the same conditions as in Example 1 except that the amount was changed to 102 g (equivalent to 0.0074 mol per mol of ε-caprolactam) to obtain nylon 6 pellets. Various physical properties tests were performed using the nylon 6 pellets (or pulverized products thereof) thus obtained. Table 1 shows the obtained results.

Comparative Example 1 Nylon 6 pellets were obtained by polymerization, refining and drying under the same conditions as in Example 1 except that the raw materials were charged with 10.0 kg of ε-caprolactam and 1 kg of water. Various physical properties tests were performed using the nylon 6 pellets (or pulverized products thereof) thus obtained. Table 1 shows the obtained results.

Comparative Example 2 Polymerization, refining and drying were carried out under the same conditions as in Example 1 except that the raw materials were charged with 10.0 kg of ε-caprolactam and 1 kg of water, and the pressure during polymerization was changed to 3 kg / cm ^2. Thus, nylon 6 pellets were obtained. Various physical properties tests were performed using the nylon 6 pellets (or pulverized products thereof) thus obtained. Table 1 shows the obtained results.

The types of nylon, the amount of 2,2,6,6-tetramethylpiperidone added in Examples 1-4 and Comparative Examples 1-2, and various physical properties tests (melt viscosity stability, amino terminal group concentration , The carboxyl end group concentration and the amount of ε-caprolactam detected) are shown in Table 1.

[Table 1]

[0033]

According to the present invention, melt spinning, melt molding,
The amount of ε-caprolactam produced during film formation is small,
Nylon 6 or a copolymer thereof having an improved operation stability can be obtained by forming a high-quality fiber or film with good thermal stability.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4J001 DA01 DB01 DB04 DD20 EA06 EA08 EA15 EA16 EA17 EB08 EB09 EB36 EB37 EC07 EC08 EC09 EC47 EE65C EE69C FA03 FA05 GA12 GE01 JA01 JB18

Claims (2)

[Claims] 1. Nylon 6 or a copolymer thereof, wherein at least one piperidone-based compound represented by the following formula is present in a state of being chemically bonded to a polymer chain or at a terminal thereof. . Embedded image 2. In the presence of at least one piperidone compound represented by the above formula, ε-
A method for producing nylon 6 or a copolymer thereof, comprising polymerizing caprolactam or 6-aminocaproic acid.