JP3458399B2 - Polyamide composition - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a polyamide composition having excellent moldability.

[0002]

2. Description of the Related Art When a thermoplastic resin is molded by extrusion molding, an injection molding machine or the like, one of the important molding conditions is the melt viscosity of a raw material resin used for molding. On the other hand, for the purpose of improving the properties of various thermoplastic resins, mixing two or more kinds of resins having different properties is a commonly adopted method. At this time, when two or more kinds of resins having reactive groups at the terminals such as polyamide are melt-mixed, the melt viscosity of the resin composition after mixing significantly increases the arithmetic mean value or logarithmic mean value of the melt viscosity of the raw resin before mixing. There may be observed a phenomenon exceeding the above. When a resin composition containing two or more kinds of polyamides is melted by heating and subjected to molding, when the melt viscosity of the resin composition reaches a value that greatly exceeds the melt viscosity of a single starting polyamide, the moldability decreases. The problem of doing.

When the viscosity of the molten resin is greatly increased in this way, the molding machine requires a remarkably large extrusion power and injection pressure, and the extrusion amount and the injection amount are likely to be unstable, and it is difficult to secure the thickness accuracy. The transferability is also reduced. Further, since a large pressure resistance is required for the molten resin flow path pipe, the die, and the injection nozzle, there is a problem that equipment needs to be improved or a new facility needs to be installed.

[0004]

The object of the present invention is to overcome the above-mentioned problems of the prior art and to suppress an increase in melt viscosity when melt mixing two or more polyamides, and to provide excellent moldability. Another object is to provide a polyamide composition.

[0005]

Means for Solving the Problems The inventors of the present invention have completed the present invention as a result of extensive studies to solve the above problems. The gist of the present invention is, therefore, a polyamide composition obtained by mixing two or more kinds of polyamides, in which at least one polyamide is formed by a polycondensation reaction of metaxylylenediamine and adipic acid. A polyamide composition comprising a unit of 70 mol% or more, and a difference in terminal group concentration of the polyamide after mixing satisfies the following formula (1):

[0006]

[Equation 2] | [Terminal amino group concentration]-[Terminal carboxyl group concentration] | ≧ (16 + 0.33 × φ) × 10 −6 equivalent /
g (1) Here, φ in the formula (1) is a polyamide or a polyamide containing 70 mol% or more of structural units produced by the polycondensation reaction of metaxylylenediamine and adipic acid in the polyamide composition. It represents the mixing ratio (% by weight) of the copolymer. Hereinafter, the present invention will be described in detail.

It is known that the polymer substance is a mixture of a large number of polymer chains having different lengths, and the polyamide is a mixture of a large number of polymer chains having a different length, as in this example. In the case of polyamide, one polymer chain has two end groups unless it is branched, but the end groups of all polymer chains are not the same, and (a) both end groups are amino groups. , (B) with both terminal groups being carboxyl groups,
(C) One having an amino group and the other having a carboxyl group,
Is a mixture of polymer chains having three types of terminal groups. Which of these (a) to (c) is the terminal group depends on the type of raw material, the proportion of the raw material, the production method, the modifier, the end capping agent and the like in the production of polyamide.

According to the experiments of the present inventor, it has been found that when two or more polyamides are melt-mixed, an increase in melt viscosity of the mixed polyamide composition can be suppressed in the case of a combination of specific raw materials. That is, regarding a polyamide composition obtained by melt-mixing two or more kinds of polyamides, the terminal amino group concentration (hereinafter referred to as “(A)”) and the terminal carboxyl group concentration (hereinafter referred to as “( B) "is displayed.) Is | (A)-(B) | ≧
When the relationship of 16 × 10 ⁻⁶ equivalent / g is satisfied, increase in melt viscosity of the polyamide composition obtained by melt mixing can be suppressed, and a polyamide composition having good moldability can be obtained. Here, (A) and (B) of the polyamide composition can be confirmed by an acid-base titration method generally performed in the technical field of polyamide.

│ (A)-(B) │ <16 × 10 ^-6 equivalent /
When the relationship of g is satisfied, the melt viscosity of the polyamide composition after mixing greatly exceeds the melt viscosity of the raw polyamide before mixing, resulting in a composition having poor moldability, which is not preferable. Two
The details of the reason why the melt viscosity greatly increases when melt mixing more than one kind of polyamide is unknown, but it is because the reaction occurs between the terminal groups of the polymer chain and a long polymer chain is generated. Presumed.

In order to obtain a composition in which the absolute value of the difference between (A) and (B) of the polyamide-based composition after mixing is 16 × 10 ⁻⁶ equivalent / g or more, at least one polyamide composition is used. By modifying the terminal, you can use a polyamide with a different amino group concentration and carboxyl group concentration,
Also, the absolute value of the difference between the terminal amino group concentration and the terminal carboxyl group concentration after mixing two or more polyamide ratios is 16
It can be obtained by, for example, mixing so that the concentration becomes × 10 ⁻⁶ equivalent / g or more.

Further, according to the experiments conducted by the present inventor, in a polyamide composition obtained by mixing two or more kinds of polyamides, at least one polyamide is a structural unit formed by a polycondensation reaction of metaxylylenediamine and adipic acid. In the case of a polyamide or a polyamide copolymer containing 70 mol% or more of styrene, 70 mol% of structural units produced by the polycondensation reaction of metaxylylenediamine and adipic acid are contained.
As a result of examining the mixing ratio of the polyamide or the polyamide copolymer contained above and the melt viscosity of the polyamide composition melt-mixed, | (A)-(B) | ≧ (16 + 0.33)
× φ) × 10 ⁻⁶ equivalents / g or more, in particular, the increase in melt viscosity of the polyamide-based composition obtained by melt-mixing can be suppressed, and a polyamide-based composition with good moldability can be obtained. I knew that. Here, φ represents the mixing ratio (% by weight) of the polyamide or polyamide copolymer containing 70 mol% or more of the structural unit formed by the polycondensation reaction of metaxylylenediamine and adipic acid in the polyamide composition. .

In a polyamide composition obtained by mixing two or more kinds of polyamides, at least one polyamide contains 70 mol% or more of structural units formed by a polycondensation reaction of metaxylylenediamine and adipic acid, or In the case of a polyamide copolymer, the details of the reason due to the mixing ratio of the polyamide is unknown, but since the reactivity of the end group of the polyamide is different from that of other polyamides, the higher the mixing ratio of the polyamide is, It is presumed that the reaction between the terminal groups becomes difficult to occur.

The polyamide-based composition (|
The upper limit of (A)-(B) |) is not particularly limited, but (|
If the value of (A)-(B) |) is considerably increased, the melt viscosity is significantly reduced, and when a polyamide-based composition is used as a raw material to produce a molded article by an extrusion molding method, the extrusion amount is unstable. Is likely to occur, and there is a risk of problems such as difficulty in ensuring the thickness accuracy of the sheet or film, etc., so generally 100 × 10 ⁻⁶ equivalent / g or less, preferably 80
It is desirable that it is not more than × 10 ⁻⁶ equivalent / g.

The polyamide-based composition according to the present invention is selected from a plurality of polyamides by selecting and combining two or more kinds, and any kind of polyamide-based composition may be used as long as the mixed polyamide-based composition satisfies the above requirements. Combinations may be used, and the type of raw material polyamide is not particularly limited. Specific examples of the raw material polyamides include polyamides obtained by ring-opening polymerization of lactams such as ε-caprolactam, enantolactam, and lauryllactam; Polyamide obtained by condensation, polyamide obtained by polycondensation of nylon salt of diamine and dicarboxylic acid, and also various lactams described above, aminocarboxylic acid, and a mixture of nylon salt of diamine and dicarboxylic acid appropriately mixed Examples thereof include polyamide copolymers obtained by polycondensation. Specific examples of the diamine include ethylenediamine, trimethylenediamine, hexamethylenediamine, metaxylylenediamine, paraxylylenediamine, cyclohexanediamine, aliphatic diamines such as 1,3-bisaminomethylcyclohexane, and alicyclic diamines. To be Specific examples of dicarboxylic acids include malonic acid, succinic acid, glutaric acid, adipic acid, 1,4-cyclohexanedicarboxylic acid, terephthalic acid, isophthalic acid, aliphatic dicarboxylic acids such as phthalic acid, alicyclic dicarboxylic acids, and aromatics. Group dicarboxylic acids and the like. Further, in the present invention, even when the above-mentioned various polyamides are manufactured, those having modified terminal groups and different terminal group concentrations are treated as different polyamides. For example, what modified the terminal group at the time of manufacturing polycapramide is treated as different from unmodified polycapramide.

The polyamide used in the present invention is produced by a known method. For example, it is produced by a method in which lactam is heated under pressure in the presence of a water solvent and polymerized while removing added water and condensed water. Further, it is produced by a method in which a nylon salt composed of a diamine and a dicarboxylic acid is heated in the presence of a water solvent under pressure to polymerize while removing added water and condensed water. It is also produced by a method of directly adding diamine to molten dicarboxylic acid and polycondensing under normal pressure. In any case, a polymer having a high molecular weight obtained by solid-state polymerization after melt polymerization can also be used.

The relative viscosity of the raw material polyamide used in the present invention (value measured by dissolving 1 g of polyamide in 100 ml of 96% sulfuric acid at 25 ° C.) is 1.7 to 5.5, preferably 1.9 to 5. It is preferably in the range of 0. When the relative viscosity is less than 1.7, the polyamide has a low molecular weight, does not exhibit the necessary mechanical strength when used as a molded article such as a film, and has a low melt viscosity, which causes inconvenience during molding. When the relative viscosity exceeds 5.5, the polyamide has a high melt viscosity, which imposes a heavy load on the molding machine during molding and makes mixing difficult, which is not preferable as a raw material of the present invention.

Further, the polyamide composition according to the present invention contains a lubricant, an antistatic agent, an antioxidant, an antiblocking agent, a stabilizer, within a range that does not significantly change the melt viscosity.
Various additives such as dyes, pigments and inorganic fine particles, and other thermoplastic resins can be added. Further, a modified polyolefin, an ionomer resin, an elastomer or the like may be added in order to improve the flex resistance etc. within a range in which the melt viscosity of the polyamide composition is not significantly changed.

The polyamide composition according to the present invention can be used in various injection molding methods, extrusion molding methods, blow molding methods, etc., using a dry blended product or a melt blended product prepared by melt-mixing in advance with an extruder or the like and pelletizing it. With the molding technique of, it is possible to mold into a desired final molded product. Examples of molded articles include automobile parts, machine equipment parts, sheets, films (single layer, multi-layer), laminates with paper, blow bottles and the like, and secondary processed articles include trays, pouches and the like. Furthermore, in order to enhance the mechanical strength of the polyamide composition according to the present invention, glass fiber, carbon fiber, calcium carbonate,
Fibers or fillers such as mica and potassium titanate can be added and used as a molding material.

Glass fibers are used as particularly preferable fillers, and when glass fibers are mixed and used,
It is preferable to use 20 to 150 parts by weight of glass fiber in 100 parts by weight of the polyamide composition according to the present invention. When the content of the glass fiber is less than 20 parts by weight based on 100 parts by weight of the polyamide composition of the present invention, the reinforcing effect is not remarkable, and when it exceeds 150 parts by weight, melt-kneading may be difficult. is there.

[0020]

EXAMPLES The contents and effects of the present invention will be described below in more detail with reference to Examples, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded. The terminal group concentrations, melt viscosities, and relative viscosities of the polyamides used in the following examples and comparative examples and the polyamide-based compositions obtained by mixing these were measured by the following methods.

<Terminal group concentration> Using an automatic titrator GT-01 manufactured by Mitsubishi Kasei Co., Ltd., dissolved in a mixed solution of phenol and ethanol, hot benzyl alcohol, etc., the terminal amino group concentration is hydrochloric acid aqueous solution, terminal carboxy. The concentration was measured with an aqueous sodium hydroxide solution. <Melt Viscosity> The melt viscosity was measured with a capillary rheometer (capillary L / D = 40) manufactured by Instron at a resin temperature of 270 ° C. and a shear rate of 100 sec ^-1 . <Relative Viscosity> Using a Canon Fenske type viscometer, 1 g of the sample was dissolved in 100 ml of 96% sulfuric acid and measured at 25 ° C.

Polycapramide A 200 l autoclave was charged with ε-caprolactam 60.
61.6g of Kg, 1.2Kg of water and hexamethylenediamine
Was charged, the mixture was sealed in a nitrogen atmosphere, the temperature was raised to 260 ° C., the reaction was carried out under pressure for 2 hours while stirring, and then the pressure was gradually released to 200 torr and the reaction was carried out under reduced pressure for 2 hours.
After introducing nitrogen and restoring the pressure to normal pressure, stirring was stopped, the reaction product was extracted as strands from the autoclave and made into chips, and unreacted monomers were extracted and removed using boiling water and dried to produce polycapramide A. . The ones of the terminal amino group concentration] is 37 × 10 ^-6 eq / g, [terminal carboxyl group concentration] is 4 × 10 ^-6 eq / g, melt viscosity 2800Poise, relative viscosity is 3.5.

Polycapramide B 200 l of autoclave, ε-caprolactam 60
Kg, 3 kg of water and 219 g of adipic acid were charged, the atmosphere was replaced with nitrogen, and then the reaction was carried out under pressure at 270 ° C. under a pressure of 8 kg for 1 hour. Then release the pressure, reduce the pressure to 150 torr,
The reaction was performed under reduced pressure for 2 hours, the stirring was stopped, the pressure was restored to 8 kg with nitrogen, and the reaction product was extracted as a strand from the autoclave. The extracted strand was cut into chips, extracted with demineralized water to remove unreacted monomers and oligomers, and dried to produce polycapramide B. [Terminal amino group concentration] of this compound 7 × 10 ^-6 eq / g, [terminal carboxyl group concentration] is 55 × 10 ^-6 eq / g, melt viscosity 2800Poise, relative viscosity is 3.5.

Polycapramide C 200 l autoclave, ε-caprolactam 60
After charging Kg and 1.2 Kg of water, sealing in a nitrogen atmosphere, raising the temperature to 260 ° C., reacting under pressure for 2 hours with stirring, and then gradually releasing the pressure to 200 torr and reducing the pressure for 2 hours. The reaction was carried out. After introducing nitrogen and returning to normal pressure, stirring was stopped, the reaction product was extracted as strands from the autoclave and made into chips, and unreacted monomers were extracted and removed using boiling water and dried to produce polycapramide C. . [Terminal amino group concentration] of this compound 29 × 10 ^-6 eq / g, [terminal carboxyl group concentration] is 28 × 10 ^-6 eq / g, melt viscosity 6000Poise, relative viscosity is 3.7.

Polycapramide D 200 l of autoclave, ε-caprolactam 60
After charging Kg, 3 kg of water and 150 g of adipic acid and purging with nitrogen, the reaction was carried out under stirring at 270 ° C. and a pressure of 8 kg for 1 hour. Then release the pressure, reduce the pressure to 150 torr,
The reaction was performed under reduced pressure for 2 hours, the stirring was stopped, the pressure was restored to 8 kg with nitrogen, and the reaction product was extracted as a strand from the autoclave. The extracted strand was cut into chips, extracted with demineralized water to remove unreacted monomers and oligomers, and dried to produce polycapramide D. [Terminal amino group concentration] of this product is 24 × ^10-6
Equivalent / g, [terminal carboxyl group concentration] is 42 × 10 ^-6
Equivalent / g, melt viscosity 2100 poise, relative viscosity 3.0.

Polymeta-xylylene adipamide Product name MX Nylon 6007 manufactured by Mitsubishi Gas Chemical Co., Inc.
The [terminal amino group concentration] of this product is 12 x 10^-6Equivalent /
g, [terminal carboxyl group concentration] is 61 × 10 ^-6Equivalent /
g, melt viscosity is 4800 poise, and relative viscosity is 2.
It is 6.

Polyhexamethylene adipamide Leona 66 manufactured by Asahi Kasei Kogyo Co., Ltd. This product has a [terminal amino group concentration] of 30 × 10 ⁻⁶ equivalent / g, a [terminal carboxyl group concentration] of 113 × 10 ⁻⁶ equivalent / g, a melt viscosity of 6000 poise, and a relative viscosity of 3.3.

Example 1 A resin composition prepared by mixing polycapramide B and polymethaxylylene adipamide at a mixing ratio (weight ratio) of 60:40 was used at an resin temperature of 270 ° C. using an extruder equipped with a strand die. It was melt-kneaded and pelletized. With respect to the obtained pellets, the terminal amino group concentration, the terminal carboxyl group concentration and the melt viscosity were measured, and the results are shown in Table 1 together with the value of the polyamide used.

Examples 2 to 4 and Comparative Examples 1 to 5 In the description of Example 1, pellets were melt-kneaded in the same manner as in Example 1 except that the kind of polyamide and the mixing ratio were changed as shown in Table 1. Turned into With respect to the obtained pellets, the terminal amino group concentration, the terminal carboxyl group concentration and the melt viscosity were measured, and the results are shown in Table 1 together with the value of the polyamide used.

[0030]

In Table 1, each abbreviation has the following meaning. NH2: Terminal amino group concentration COOH: Terminal carboxyl group concentration

[0032]

The polyamide composition according to the present invention has 2
The composition obtained by melt-mixing more than one kind of polyamide can suppress the increase of melt viscosity, has excellent moldability, and has a particularly remarkable effect that troubles due to increase of melt viscosity do not occur. The above utility value is extremely high.

Front Page Continuation (72) Inventor Hiroyuki Mishima 5-6-2 Higashi-Hachiman, Hiratsuka City, Kanagawa Mitsubishi Gas Chemical Co., Ltd., Plastics Center (56) Reference JP-A-2-235960 (JP, A) 2-502735 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C08L 77/00-77/12 C08K 7/14

Claims (4)

(57) [Claims] 1. A polyamide composition comprising a mixture of two or more polyamides, wherein at least one polyamide has 70 mol% or more of structural units formed by a polycondensation reaction of metaxylylenediamine and adipic acid. Polyamide composition containing polyamide or polyamide copolymer, wherein the difference in terminal group concentration of the polyamide after mixing satisfies the following expression (1): [Formula 1] | [Terminal amino group concentration ]-[Terminal carboxyl group concentration] | ≧ (16 + 0.33 × φ) × 10 −6 equivalent /
g (1) Here, φ in the formula (1) is a polyamide or a polyamide containing 70 mol% or more of structural units produced by the polycondensation reaction of metaxylylenediamine and adipic acid in the polyamide composition. It represents the mixing ratio (% by weight) of the copolymer. 2. A polyamide or a polyamide copolymer containing 70 mol% or more of a structural unit formed by a polycondensation reaction of metaxylylenediamine and adipic acid, and a polyamide formed by a ring-opening polymerization reaction of ε-caprolactam, or A polyamide composition obtained by mixing a polyamide copolymer containing 60 mol% or more of ε-caprolactam, wherein the difference in terminal group concentration of the polyamide after mixing is:
A polyamide composition which satisfies the formula (1) of claim 1. 3. The polyamide composition 10 according to claim 1.
Polyamide-based composition for molding material obtained by compounding 20 to 150 parts by weight of glass fiber with respect to 0 part by weight 4. A film or sheet comprising the polyamide composition according to claim 1.