JPH08208834A - Polyamide resin - Google Patents

Abstract

PURPOSE: To obtain a polyamide resin, having a specific viscosity, having the terminal groups comprising specified plural groups, excellent in moldability, flex resistance at low temperatures, tensile strength, etc., and useful as members for automobiles, aircraft, etc., containers, films, etc. CONSTITUTION: This resin has terminal groups comprising (A) a group of the formula CONHR (R is a 1-22C aliphatic hydrocarbon group), (B) COOH and (C) NH2 or a group of the formula NHCOR' (R' is a 1-5C hydrocarbon group) and the ratio of the numbers of the groups (A), (B) and (C) satisfy the formula [a/(a+b)]×100>=5 [(a) and (b) are each the number of the groups (A) and (B)] and the formula 2<=[a/(a+b+c)]×100<40 [(c) is the number of the groups (C)] and has 2.5-6 relative viscosity.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a polyamide resin. More specifically, the present invention relates to a polyamide resin having excellent mechanical properties and moldability and having little haze unevenness.

[0002]

BACKGROUND OF THE INVENTION Polyamide resins are widely used as engineering plastics because of their excellent mechanical properties, but their bending resistance, especially at low temperatures, and transparency are still desired to be improved. For example, when manufacturing a film or sheet made of polyamide resin,
Although the resin may be cooled with water or the like, in such a case, the so-called haze unevenness that causes cloudiness during cooling due to the crystallinity of polyamide, impairs transparency, and causes nonuniform transparency is generated. was there.

Conventionally, attempts have been made to improve the above-mentioned drawbacks by using additives, but as described above, it is considered that the haze unevenness is derived from the degree of crystallization of the polyamide resin itself, and therefore additives are used. However, it was not always possible to improve sufficiently. In addition, in the use of additives, for example, when a polyamide resin is used as a food packaging material, there is a problem of elution, and the types of additives are also limited.

[0004]

SUMMARY OF THE INVENTION It is an object of the present inventors to provide a polyamide resin which is excellent in mechanical properties, particularly bending bending resistance at low temperature, tensile strength, and transparency.

[0005]

DISCLOSURE OF THE INVENTION As a result of intensive studies by the present inventors for improving the mechanical properties and transparency of polyamide resins, polyamides of specific relative viscosity having specific hydrocarbon groups as terminal groups have been obtained. It was found that the resin has excellent mechanical properties, especially bending bending resistance and tensile strength at low temperature, and also excellent melt flowability and mold release property. Furthermore, when this polyamide resin is formed into a film, it has good haze. Film can be obtained, also polyethylene,
Polypropylene, polybutadiene, polyisobutylene,
The present invention has been completed by knowing that it has good compatibility with polyolefin resins such as polystyrene.

That is, an object of the present invention is to provide a polyamide resin of great industrial value,
The gist is that the terminal group is (a) -CONHR group (R represents an aliphatic hydrocarbon group having 22 or less carbon atoms.) (B) -COOH group and (c) -NH ₂ group and / or -NHCOR 'group (R'
Represents a hydrocarbon group having 1 to 5 carbon atoms. ) And the ratio of the numbers of end groups (a), (b) and (c) is

[0007]

(Equation 3)

[0008] and

[0009]

[Equation 4]

It exists in a polyamide resin satisfying the above conditions and having a relative viscosity of 2.5 to 6.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The polyamide referred to in the present invention is a polyamide obtained by polycondensation of a lactam having three or more membered rings, a polymerizable ω-amino acid, or a dibasic acid and a diamine and their copolymerization. Specific examples of the raw material for these polyamides include ε-caprolactam, enanthlactam, capryllactam, lauryllactam,
lactams such as α-pyrrolidone and α-piperidone,
Ω-such as 6-aminocaproic acid, 7-aminoheptanoic acid, 9-aminononanoic acid, 11-aminoundecanoic acid
Amino acids, adipic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecadioic acid, hexadecadioic acid, hexadecenedioic acid, eicosandioic acid, eicosadiendioic acid, diglycol Dibasic acids such as acids, 2,2,4-trimethyladipic acid, xylylenedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, terephthalic acid and isophthalic acid, hexamethylenediamine, tetramethylenediamine, nonamethylenediamine, and Decamethylenediamine, dodecamethylenediamine, 2,2,4 (or 2,4,4) -trimethylhexamethylenediamine,
Examples thereof include bis- (4,4'-aminocyclohexyl) methane and diamines such as metaxylylenediamine.

The polyamide resin of the present invention has a modified terminal group. As the terminal group, a carboxyl group and an amino group derived from a polyamide raw material and an aliphatic group (--CONHR group) introduced by modification are used. And -NHC
There is an OR 'group). Examples of the aliphatic hydrocarbon group represented by R in the -CONHR group (wherein R is an aliphatic hydrocarbon group having 22 or less carbon atoms, preferably 12 to 22 carbon atoms) include a dodecyl group, a tridecyl group, a tetradecyl group, and tetradecenyl. And aliphatic hydrocarbon groups such as group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, octadecenyl group, eicosyl group and docosyl group.

The -NHCOR 'group (provided that R'
Is a hydrocarbon group having 1 to 5 carbon atoms. Examples of the hydrocarbon group represented by R'in () include an aliphatic hydrocarbon group such as a methyl group, an ethyl group, a propyl group, a butyl group and a pentyl group. The abundance of hydrocarbon groups such as R and R'is measured by gas chromatography after hydrolyzing the polyamide with hydrochloric acid. The existing amount of amino groups is measured by dissolving polyamide in phenol and titrating with 0.05N hydrochloric acid. The amount of carboxyl groups is measured by dissolving polyamide in benzyl alcohol and titrating with 0.1N caustic soda.

The ratio of the numbers of the terminal groups (b) -CO ₂ H groups and (a) -CONHR groups in the polyamide resin of the present invention is

[0015]

(Equation 5) Is preferably satisfied. Particularly preferably

[0016]

(Equation 6)

It is If this amount is too small, the effect of improving the bending resistance and the melt fluidity is small. Further, the effect of improving the haze when the film is formed cannot be expected. A relatively high value is desirable from the viewpoint of physical properties, but a polyamide resin having too high a value tends to deteriorate haze when formed into a film using an appropriate water repellent. Therefore, the -CONHR group of (a) is 40% of all the terminal groups (a) + (b) + (c) and 2%.
It is preferably at least 3%. That is

[0018]

(Equation 7)

[0019] When it is less than 2, the haze of the film is not improved.

The polyamide resin of the present invention has a relative viscosity of JI
1% concentration in 98% sulfuric acid, temperature 2 according to SK6810
The value measured at 5 ° C is 2.5 to 6, preferably 2.5 to
It is 5. If the relative viscosity is low, improvement in fatigue resistance cannot be expected. On the contrary, if it is too high, the melt fluidity is impaired, which is not preferable. In order to produce the terminal-modified polyamide resin of the present invention, the above polyamide raw material (monomer) is used as a monoamine having 12 to 22 carbon atoms, or a monoamine having 12 to 22 carbon atoms and a monoamine having 2 to 6 carbon atoms. Polycondensation is performed in the presence of carboxylic acid.

As the above-mentioned monoamine having 12 to 22 carbon atoms, dodecylamine, tridecylamine, tetradecenylamine, pentadecylamine, hexadecylamine,
Octadecylamine, octadecenylamine, eicosylamine, docosylamine, etc. may be mentioned, and the amount thereof used is 1 mol of the polyamide raw material (1 mol of the monomer constituting the repeating unit or 1 mol of the monomer unit) in terms of milliequivalent amine groups (carboxylic acid). The amount of amino groups that react with 1 equivalent in a ratio of 1: 1 to form an amide bond is 1 equivalent).
meq / mol to 14 meq / mol, preferably 0.5 m
eq / mol to 12 meq / mol. In addition, examples of the monocarboxylic acid having 2 to 6 carbon atoms include acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, etc.
It is 7 meq / mol, preferably 0-6 meq / mol.

If desired, in addition to the above monoamine or monoamine and monocarboxylic acid, ethylenediamine, trimethylenediamine, tetramethylenediamine,
Pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, undecamethylenediamine, dodecamethylenediamine, tridecamethylenediamine, hexadecamethylenediamine, octadecamethylenediamine, 2, 2,4 (or 2,4
4) -aliphatic diamines such as trimethylhexamethylenediamine, cyclohexanediamine, methylcyclohexanediamine, alicyclic diamines such as bis- (4,4'-aminocyclohexyl) methane, aromatic diamines such as xylylenediamine. Diamines such as, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, tridecadioic acid, tetradecadioic acid, hexadecadione Acids, hexadecenedioic acid, octadecadioic acid, octadecenedioic acid, eicosandioic acid, eicosendioic acid, docosandionic acid, aliphatic dicarboxylic acids such as 2,2,4-trimethyladipic acid, 1,4- Alicyclic ring such as cyclohexanedicarboxylic acid Dicarboxylic acid, terephthalic acid, isophthalic acid, or in the presence of the dicarboxylic acids such as phthalic acid, aromatic dicarboxylic acids such as xylylene carboxylic acid.

The reaction for producing the polyamide resin of the present invention may be carried out by using the above-mentioned polyamide raw material and initiating the reaction according to a conventional method. The above-mentioned carboxylic acid and amine are optional from the start of the reaction to the start of the reaction under reduced pressure. Can be added at the stage of. Further, the carboxylic acid and the amine may be added simultaneously or separately. The pressure at the end of the reaction is preferably 500 Torr or less, and preferably 4
It is preferable to set it to 00 Torr or less. If the pressure at the end of the reaction is high, the desired relative viscosity may not be obtained.
Low pressure is not a disadvantage. The reduced pressure reaction time was 0.
It is preferable to carry out the treatment for 5 hours or more, usually for 1 to 2 hours. In the present invention, the terminal carboxyl group can be controlled to a predetermined value by adjusting the polycondensation conditions (pressure at the end of reaction, time of reduced pressure reaction) and the like together with the amount of amine used.

[0024]

The present invention will be described in detail below with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist. Examples 1 to 4 and Comparative Example 1 A 200 liter autoclave was charged with 60 kg of ε-caprolactam, 1.2 kg of water and the amounts of monoamine, monocarboxylic acid, hexamethylenediamine and adipic acid shown in Table 1 below, and a nitrogen atmosphere. And seal it 2
After the temperature was raised to 60 ° C. and the reaction was performed under pressure for 2 hours with stirring, the pressure was gradually released to reduce the pressure to the pressure shown in Table 1 below.
The reaction was performed under reduced pressure for 2 hours.

After introducing nitrogen and restoring the pressure to normal pressure, stirring was stopped and the strands were extracted to form chips, and unreacted monomers were extracted and removed using boiling water and dried. The obtained chips were put into a 3.6 ounce injection molding machine (manufactured by Toshiba Machine Co., Ltd.,
IS-75S type), width 10 mm, thickness 2 mm, length 1
Using a mold for molding test pieces of 00 mm, resin temperature 250
℃, mold temperature 80 ℃, injection time 5 seconds, cooling time 10 seconds,
Specimens for tensile and bending tests were molded with a total cycle of 18 seconds. The melt flowability was shown by the injection pressure at that time (Table 1). The tensile test is 5 kg instantaneously at a temperature of -10 ° C.
It was pulled by heavy force and the number of broken pieces was counted among 20 pieces. In the bending test, the test piece was bent 180 ° at a temperature of −10 ° C., and the number of broken pieces was counted out of 20 pieces.

Separate from the above-mentioned molding, the releasability is 80 mm ×
Using a mold capable of forming a grid in which ribs of 5 mm × 4 mm are arranged at intervals of 15 mm in a frame of 80 mm, a resin temperature of 250 is used.
℃, mold temperature 80 ℃ injection time: 5 seconds, cooling time 12
Second, continuous injection molding was performed for 20 seconds in all cycles, and the number of shots until the release defect occurred was counted. ○ indicates that continuous molding was possible for 25 or more shots. × indicates that mold release failure occurred in 10 shots or less. △ indicates that mold release failure occurred between 10 and 25 shots.

The film is formed by an inflation method in which ethylene bis stearamide (EBS) is added to the above polyamide as a water repellent, and the mixture is cooled with external water using a 40 mm extruder and a 75 mm ring die.
A film having a thickness of μ was obtained. Measurement of haze is JIS K
Followed 6714. The results are shown in Table 1 below. For comparison, the result of the same operation as in Example 1 except that 1.13 meq / mol of acetic acid was used without using a monoamine having 12 or more carbon atoms is also shown.

[0028]

[Table 1]

[0029]

INDUSTRIAL APPLICABILITY The polyamide resin of the present invention has excellent mechanical properties, in particular, bending resistance at low temperature, tensile strength and transparency represented by the occurrence of haze unevenness, and also has melt flowability and releasability. Because it is excellent, injection molding,
Three-dimensional molded articles, containers, films, sheets, tubes, filaments suitable for automobiles, aircrafts, ships, electric / electronic devices, and other industrial members by various known molding methods such as extrusion molding and compression molding. It can be molded into, and is extremely useful industrially.

Claims (1)

[Claims] 1. A terminal groups (a) -CONHR group (R represents an aliphatic hydrocarbon group having 22 or less carbon atoms.) (B) -COOH groups and (c) -NH ₂ group and / or -NHCOR ′ Group (R ′
Represents a hydrocarbon group having 1 to 5 carbon atoms. ) And the ratio of the numbers of end groups (a), (b) and (c) is And And a relative viscosity of 2.5-6.