JPH0678458B2 - Resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a molding resin composition comprising a saponified polyamide resin of ethylene-vinyl acetate copolymer.

[Conventional technology]

The composition of ethylene-saponified vinyl acetate copolymer and polyamide has an oxygen barrier property based on the saponified copolymer,
Since it has useful properties such as oil resistance, solvent resistance, and impact resistance based on polyamide, its melt-molded products are used for various applications such as food packaging films, sheets, and containers. Has been. In the literature, for example, Japanese Patent Publication No.
No. 242777 discloses a molded product composed of nylon 6, nylon 66, etc. and a saponified product of an ethylene-vinyl acetate copolymer.

[Problems to be solved by the invention]

However, when such a composition is continuously melt-molded for a long time, gel is generated in the melt,
Resin debris accumulates on the screw part, discharge part, etc. of the extruder,
As a result, the physical properties of the molded product are impaired, and when the screen and nozzles are clogged when it is unfavorable, it is unavoidable to disassemble the extruder once to remove the deposits, mainly in the molding process. There is a tendency for practical problems such as poor performance to occur.

As measures against this, Japanese Patent Laid-Open Nos. 54-78749 and 54
In JP-78750, a method for improving long-run property by copolymerizing modification of polyamide is proposed, but at most, continuous melt molding of about several tens hours is possible, and melting on an industrial scale is possible. Needless to say, it is advantageous for molding if continuous operation can be performed over a longer period of time.

[Means for solving problems]

The present inventors have conducted extensive studies to solve such problems, and as a result, (i) saponified ethylene-vinyl acetate copolymer and (ii) terminal carboxyl group-containing (X / μeq / g · polymer)
And a polyamide-based resin having a relationship of satisfying the formula Y ≧ X + 5 with the terminal mamino group content (Yμeq / g · polymer) have excellent long-run property during melt molding, and gel formation and dust The inventors have found that the present invention has a remarkable effect that a molded product having good physical properties can be produced over a long period of time without causing any trouble such as adhesion of the above, and thus completed the present invention.

The saponified product of (i) ethylene-vinyl acetate copolymer used in the present invention has an ethylene content of 20 to 80 mol%, preferably
Those having a degree of saponification of 25 to 60 mol% and a vinyl acetate component of 90 mol% or more, preferably 95 mol% or more are usually used.
When the ethylene content is 20 mol% or less, the oxygen barrier property at high humidity is deteriorated, while when it is 80 mol% or more, the oxygen barrier property and the physical properties such as printability are deteriorated. Further, when the saponification degree is 90 mol% or less, oxygen barrier property and moisture resistance are deteriorated. Among such saponified products, those having an intrinsic viscosity (measured as a 15% hydrous phenol solution at 30 ° C.) of 0.7 to 1.5 dl / g, preferably 0.8 to 1.3 dl / g are preferably used in terms of mechanical strength of the molded product. To be done.

Further, the saponified copolymer is a small amount of propylene, isobutene, α-octene, α-dodecene, α-olefin such as α-octadecene, unsaturated carboxylic acid or its salt / partial alkyl ester, complete alkyl ester / nitrile / It does not matter if it contains a comonomer such as amide, anhydride, unsaturated sulfonic acid or a salt thereof.

The polyamide resin used in the present invention must have terminal carboxyl groups and amino groups satisfying the above formula.

That is, in a polyamide obtained by polymerizing or copolymerizing a lactam having 3 or more membered rings, ε-amino acids or dibasic acids with diamines, the content of terminal amino groups in the molecule is larger than the content of terminal carboxyl groups. It is adjusted to.

To produce the polyamide-based resin of the present invention, polycondensation is carried out in the coexistence of a diamine when a lactam having three or more membered rings or ω-amino acid is used, and a diamine is prepared when polycondensation is carried out with a dibasic acid and a diamine. By using an excess amount of

Specific examples of the raw material of the above polyamide include ε-caprolactam, enantolactam, capryllactam, lauryllactam, α-pyrrolidone, lactals such as α-piperidone, 6-aminoaproic acid, 7-aminoheptanoic acid, Ω-amino acids such as 9-aminononanoic acid and 11-aminoundecanoic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, Tridecadioic acid, tetradecadioic acid, hexadecadioic acid, hexadecenedioic acid, octadecadioic acid, octadecenedioic acid, eicosandioic acid,
Aliphatic dicarboxylic acids such as eicosendioic acid, docosandionic acid, 2,2,4-trimethyladipic acid, 1,4-
Alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid, dibasic acids such as terephthalic acid, isophthalic acid, phthalic acid, and aromatic dicarboxylic acids such as xylylenedicarboxylic acid may be mentioned. The diamines include ethylenediamine and trimethylene. Diamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, undecamethylenediamine, dodecamethylenediamine, tridecamethylenediamine, hexadecamethylenediamine, octa Decamethylenediamine, 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 And so on.

The amount of the diamine used is 0.6 to 20 meq / mol, preferably 0.8 to 18 me, based on the polyamide raw material as the amount of amino groups.
q / mol. When a dibasic acid is used, it is preferable that the excess amount of diamine with respect to the acid be the above-mentioned amount.

The reaction for producing the polyamide resin of the present invention is carried out using the above-mentioned polyamide raw material under reduced pressure according to a conventional method for 0.5 hours or more and usually 1-2 hours.

The polyamide resin used in the present invention has a carboxyl group and an amino group as terminal groups, but in the present invention, the content of the carboxyl group (X μeq / g · polymer) and the content of the amino group (Yμq / g / polymer)
It is necessary that the relation Y ≧ X + 5, and preferably Y ≧ X + 10, be satisfied. And preferably 50 μeq / g as the absolute value of the carboxyl group content (X).
It is suitable that the amount is not more than the polymer, preferably not more than 30 μeq / g · polymer, more preferably not more than 10 μeq / g · polymer.

If a polyamide resin having many terminal carboxyl groups is used, the melt viscosity increases during melt molding, which is not preferable for molding. On the other hand, it is preferable from the viewpoint of use that the number of carboxyl groups is small, but it is difficult to produce a resin, so it is a good idea to limit the amount to at least 1 μeq / g · polymer.

The carboxyl group is measured by dissolving a polyamide resin in benzyl alcohol and titrating with 0.1N caustic soda.

Amino group dissolves polyamide resin in phenol,
Measure by titrating with 05N hydrochloric acid.

The relative viscosity (ηrel) of the polyamide resin of the present invention is JIS
The value measured in accordance with K 6810 at a concentration of 1% in 98% sulfuric acid and a temperature of 25 ° C. is 4 to 6, preferably 4 to 5. If the relative viscosity is too low, it becomes difficult to form strands and to make chips, which is not normal. On the other hand, if it is too high, the moldability will deteriorate.

The mixing ratio of the saponified product of ethylene-vinyl acetate copolymer (i) and the above-mentioned polyamide resin (ii) is not limited at times, but is usually (i) / (ii) = 98/2 to 2/98 on a weight basis. Is 95
/ 5 to 10/90 is suitable. When it is 98/2 or more, the effect of improving the physical properties such as impact strength of the saponified ethylene-vinyl acetate copolymer is not recognized, while when it is 2/98 or less, the effect of improving the oxygen barrier property of the polyamide resin is not obtained.

The composition of the present invention is melt-molded into a pellet, film,
It is molded into various molded products such as sheets, containers, and bars. As the melt molding method, known molding means such as extrusion molding, blow molding, and injection molding are adopted.

The melt molding temperature is in the range of 150 to 270 ° C, more specifically, the discharge temperature of the extruder is 200 to 240 ° C and the screw compression temperature is 180 to 2
You can choose from 30 ℃.

The resin composition of the present invention may contain various known additives such as various stabilizers, fillers, pigments, dyes, lubricants, antiblocking agents, and various thermoplastic resins.

[Work]

In the present invention, by using a polyamide-based resin whose terminal carboxyl group and amino group are adjusted to a specific ratio, when melt-molding a mixture with an ethylene-vinyl acetate copolymer saponification product, Even if the molding operation is continued for a long period of time, there is no risk of problems such as gelation and thickening.

〔Example〕

Next, the composition of the present invention will be described more specifically with reference to examples.

[Production Example 1 of Polyamito Resin] A polyamide resin was produced by the following method.

In a 200 l autoclave, 60 kg of ε-caprolactam and water
Charge 1.2 kg and the amount of diamine shown in Table 1 below, or diamine and dicarboxylic acid, make a nitrogen atmosphere, and seal.
After the temperature was raised to 0 ° 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, and 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.

Table 1 shows the relative viscosity, the amount of terminal carboxyl groups, and the amount of terminal amino groups of the obtained polyamide resin (referred to as N-1).

[Saponified ethylene-vinyl acetate copolymer] Two kinds of saponified products were prepared as shown in Table 2.

[Examples 1 and 2] Pellets of a polyamide resin and a saponified product of an ethylene-vinyl acetate copolymer were mixed using a Henschel mixer, supplied to an extruder equipped with a T-die, and melt-kneaded. A film having a thickness of 20μ was manufactured by extrusion. The conditions for extrusion molding are as follows.

Extruder: 40 mm extruder Screw: Full flight screw Extrusion temperature: Extruder 230 ° C Die 240 ° C Screw rotation speed: 40 rpm The results obtained are shown in Tables 3 and 4.

[Polyamide Resin Production Example 2] Into a 200 autoclave, 60 kg of ε-caprolactam was charged, sealed in an N ₂ atmosphere, heated to 150 ° C., and dissolved while stirring 12.9 kg of AH salt (hexamethylenediamine / adipine). Acid) aqueous solution (40% concentration) and the amount of laromin C-260 (trade name, manufactured by BASF Japan Ltd.) described in Table 5 are added to the mixture while concentrating while controlling the internal pressure to 12 kg / cm ² G and raising the temperature to 270 ° C. , The reaction was carried out. Then, the pressure was gradually released to a pressure shown in Table 5, and the reaction was performed under reduced pressure for 2 hours.

After N ₂ was introduced and the pressure was restored to normal pressure, stirring was stopped and the strands were withdrawn to form chips, and the taste reaction monomer was extracted and removed using boiling water and dried.

Relative viscosity of the obtained polyamide, terminal carboxyl machine,
The terminal amino group is shown in Table 5.

[Examples 3 to 4] Polyamide resins N-2 to N- obtained as described above.
3, and the pellets of the saponified ethylene-acetic acid copolymer shown in Table 2 were mixed at a mixing ratio shown in Table 6 using a Henschel mixer and fed to an extruder equipped with a T-die. It was melt-kneaded and extruded from a T-die to produce a film having a thickness of 20 μm.

The conditions for extrusion molding are as follows.

Extruder: 40 mm Extruder Screw: Full flight screw Extrusion temperature: Extruder 200 ° C. Die 205 ° C. Screw rotation speed: 40 rpm The obtained results are shown in Table 6.

[Effect of the invention] The resin composition of the present invention has extremely good melt stability,
When formed into a molded product, it has excellent mechanical properties and oxygen barrier properties.

Claims (3)

[Claims] 1. The content (μeq / g · polymer) of (i) a saponified ethylene-vinyl acetate copolymer and (ii) a terminal carboxyl group (X) and a terminal amino group (Y) is represented by the formula Y ≧ A resin composition comprising a polyamide resin which satisfies X + 5 and has a relative viscosity of 4 to 6 measured at a temperature of 25 ° C. in 98% concentrated sulfuric acid of 1%. 2. The weight mixing ratio of (i) and (ii) is (i) /
The composition according to claim 1, wherein (ii) = 98/2 to 2/98. 3. The composition according to claim 1, wherein the absolute value of the terminal carboxyl group (X) content is 10 μeq / g · polymer or less.