JPS63175051A - Resin composition - Google Patents

Abstract

PURPOSE:To obtain a resin composition with excellent melt thermal stability capable of providing molded articles having improved mechanical characteristics, gas barrier properties, etc., and hardly any fisheye, by blending saponified ethylene-vinyl acetate copolymer with a specific polyamide based resin, etc. CONSTITUTION:A resin composition obtained by blending (A) saponified ethylene-vinyl acetate copolymer with 20-80mol.% ethylene content and >=95mol.% saponification degree of the vinyl acetate component with (B) a polyamide based resin with contents (muequiv./g.polymer) of terminal carboxyl groups (X) and terminal amino groups (Y) satisfying the formula Y>=X+5 and (C) an alpha-olefinic ionomer resin at 98/2-2/98, preferably 95/5-10/90 weight ratio [(A)/(B)] of the components (A) to (B) and 2/98-50/50, preferably 2/98-30/70 weight ratio [(C)/(A)+(B)] of the component (C) to the total of the components (A) and (B).

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention provides a resin composition suitable for molding comprising a saponified ethylene-vinyl acetate copolymer, a specific polyamide resin, and an α-olefin ionomer resin. Regarding.

[Conventional technology]

In recent years, films that shrink with hot water or hot air have been used for food packaging, but the required characteristics are as follows:
It is said that it should have mechanical strength to maintain the shape of the contents, barrier properties to prevent rancidity and drying, good dimensional stability at room temperature, and high shrinkage at high temperatures.

As a composition for such a use, a composition consisting of a saponified ethylene-vinyl acetate copolymer, a polyamide resin, and an α-olefin ionomer resin is known (Japanese Patent Application Laid-Open No. 1973-1330!). ;0), this composition had the disadvantage that it did not have sufficient melting thermal stability and often formed a gel-like substance, resulting in a large number of fish eyes in the film.

[Purpose of the invention]

As a result of intensive research to solve such problems, the present inventors found that (I) saponified ethylene-vinyl acetate copolymer,
(II) A polyamide resin in which a relationship satisfying the formula Y≧X-)-j is established between the terminal carboxyl group content (Xμsq/, 9・polymer) and the terminal amine group content (YμeCL/9・polymer), and (III) found that a composition consisting of an α-olefin ionomer resin has excellent melting thermal stability, does not cause problems such as the formation of a gel over a long period of time, and can stably produce products with fewer fish eyes. The invention has been completed.

[Towards invention]

The saponified ethylene-vinyl acetate copolymer (I) used in the present invention has an ethylene content of 0 to 0%, preferably 2! to 60 mol%, and those having a degree of saponification of the vinyl acetate component of 90 mol% or more, preferably 93 mol% or more are usually used. If the ethylene content is less than 20 mol %, the oxygen barrier properties at high humidity will decrease, while if it is more than 10 mol %, physical properties such as oxygen barrier properties and printability will deteriorate.

Furthermore, if the degree of saponification is less than 90 mol%, oxygen barrier properties and moisture resistance will decrease. Among these saponified products, the intrinsic viscosity (73%
Measured at 30℃ as a water-containing phenol solution of O97~
/, j dl/i preferably o, r~/, , 7 d
i/g is preferably used in terms of mechanical strength of the molded product.

In addition, the saponified copolymer may further contain a small amount of propylene, imbutene, α-olefin such as α-octene, α-dodecene, α-octadecene, unsaturated carboxylic acid or its salt, partial alkyl ester, complete alkyl ester, nitrile, etc. It may contain comonomers such as amides, anhydrides, unsaturated sulfo/acids, or salts thereof.

Furthermore, the terminal carboxyl group and amino group of the polyamide resin used in the present invention must satisfy the above formula.

That is, in polyamides obtained by polymerization or copolymerization of lactams, ε-amino acids, dibasic acids, diamines, etc. having three or more sites, the content of terminal amino groups in the molecule is adjusted so as to be smaller than the content of terminal carboxyl groups. It is something that will be done.

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

Specifically, the raw materials for the polyamide include lactams such as ε-caglolactam, enantholactam, capryllactam, lauryllactam, α-pyrrolidone, and α-piperidone, 6-aminocaproic acid, 7-aminohebutanoic acid, Omega-amino acids such as deaminononanoic acid, //-aminolanticanoic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, superic acid, azelaic acid, sebacic acid, usodecanedionic acid, dodecane Dionic acid, tridecadionic acid, tetradecadionic acid, hexadecadionic acid, hexadecenedioic acid, octadecadionic acid, octadecenedione alcohol, eicosandioic acid, eicocenedioic acid, tocosandioic acid, umidatrimethyladipic acid, etc. aliphatic dicarboxylic acid, /
Dibasic acids such as alicyclic dicarboxylic acids such as lI-cyclohexanedicarboxylic acid, aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, phthalic acid, and xylylene dicarboxylic acid, and diamines include ethylenediamine, Trimethylene diamine, tetramethylene diamine, pentamethylene diamine, hexamethylene diamine, heptamethylene diamine, octamethylene diamine, nonamethylene diamine, decamethylene diamine, undecamethylene diamine, dodecamethylene diamine, tridecamethylene diamine, hexadecamethylene diamine , octadecamethylenediamine 1,2. ．． Aliphatic diamines such as 2゜da(or 2lI+'')-)limethylhexamethylenediamine, cyclohexanediamine, methylcyclohexanediamine, bis-(Il,
Examples include alicyclic diamines such as a'-aminocyclohexylenemethane and aromatic diamines such as xylylene diamine.

The amount of diamine to be used is determined based on the amount of amino groups at θ, 6 to . 1 mol of 2 o meq, preferably 1 mol of 2 o meq.

When a dibasic acid is used, it is preferable that the amount of diamine in excess of the acid is the above-mentioned amount.

The reaction for producing the polyamide resin of the present invention is carried out using the above-mentioned polyamide raw materials under reduced pressure according to a conventional method. ! r
It is usually carried out for 7 to 2 hours.

The polyamide resin used in the present invention has a carboxyl group and an amino group as terminal groups, and in the present invention, the content of the carboxyl group (XμecL/
1 topolymer 2 and amine group content t(Yμe(L 7
g・polymer) and the formula Y≧x−4−, preferably Y≧x+i.

It is necessary that the following relationship be established. and preferably 50μθq as the absolute value of carboxyl group content (X)
/i·polymer or less, preferably JOμeCL/g·polymer or less, more preferably =θμθq/g·polymer or less.

If a polyamide resin having many terminal carboxyl groups is used, the melt viscosity will increase during melt molding, which is unfavorable for molding. On the other hand, a small number of carboxyl groups is preferable from the viewpoint of use, but it causes difficulties in the production of the resin, so it is best to limit the number to at least /μ'3CL/9·polymer.

Carboxyl groups are obtained by dissolving polyamide resin in benzyl alcohol and adding 0. Measured by titration with IN caustic soda.

The amine group dissolves in the polyamide resin phenol, and the θ
, θ is measured by titration with N Shioshun.

The relative viscosity (ηrel) of the polyamide resin of the present invention is 91% concentration in sulfuric acid/% according to JI8 6ff10,
The value measured at a temperature of 5°C is -6 to 6, preferably 2 to 6. If the relative viscosity is too low, it will be difficult to form into strands and chips, which will be inconvenient in manufacturing. On the other hand, if it is too high, moldability will deteriorate.

There is no particular restriction on the mixing ratio of the saponified ethylene-vinyl acetate copolymer (I) and the above polyamide resin (■), but it is usually (I)/(II) = 9 r/2 saponified polymer on a weight basis. The effect of improving physical properties such as the improvement of impact strength is not observed, and on the other hand, the effect of improving the oxygen barrier properties of the polyamide resin cannot be obtained when it is less than co/qg.

The α-olefin ionomer resin (III) in the present invention refers to an ionic copolymer obtained by crosslinking metal ions to an α-olefin and an α,β unsaturated carboxylic acid conductor copolymer. Examples of α-olefins include ethylene and propylene, and examples of α,β unsaturated carboxylic acid conductors include acrylic acid, methacrylic acid, itaconic acid, methyl acrylate, ethyl acrylate, and methacrylate. Examples include methyl acid, ethyl methacrylate, and the like. Also, as a metal ion, the valence is 7~
Divalent materials such as Na''2Mg and Zn can be mentioned.

The mixing ratio of the α-olefin ionomer resin (■), the saponified ethylene-vinyl acetate copolymer (I), and the total amount of the polyamide resin (II) is usually on a weight basis @)
/ (I) + (II) = :2/riff-! ;0
/go, preferably co/qg to 3o/7o. α−
If the amount of olefinic ionomer resin is too low, mechanical strength and dimensional stability will decrease. On the other hand, if the amount is too large, the barrier properties will be impaired.

The composition of the present invention can be melt-molded into pellets, films,
It is molded into various molded products such as sheets, containers, and rods. As the melt molding method, known molding means such as extrusion molding, blow molding, injection molding, etc. are employed.

The melt temperature for melt molding can be selected from the range of 0 to 170°C, more specifically, the temperature of the extruder discharge section is 200 to 241[theta]C, and the temperature of the screw compression part is 30 to 30[deg.]C.

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

〔Example〕

Next, the composition of the present invention will be explained in more detail with reference to Examples.

Example of manufacturing polyamide resin Seven types of polyamide resins were manufactured using the following method.

2001 autoclave, ε-caglolactam AO
9, water/, = y, diamine or dicarboxylic acid in the amounts shown in Table 1 below, the temperature was raised to 240°C in a sealed nitrogen atmosphere, and the reaction was carried out under pressure for 1 hour with stirring. After this, the pressure was gradually released to the pressure shown in Table 1 below, and the reaction was carried out under reduced pressure for 2 hours.

After introducing the base element and restoring the pressure to normal pressure, stirring was stopped and strands were extracted and chipped, unreacted monomers were extracted and removed using boiling water, and the mixture was dried.

Table 1 shows the relative viscosity, amount of terminal carboxyl groups, and amount of terminal amino groups of the obtained polyamide resin.

Examples 1 to 7 and Comparative Examples/~C The polyamide resin produced in the above production example, an ethylene-vinyl acetate copolymer having an ethylene content of 3 t mol% and a saponification degree of the vinyl acetate component of 99 mol%. (manufactured by Nippon Gosei Kagaku ■, trademark, Anol ET), and α-onfin ionomer resin (manufactured by Mikata Polychemical ■, trademark, Surlinna 1t50), which is a zinc-neutralized product of ethylene-methacrylic acid copolymer, are as follows. Tri-blend at the ratio shown in the second coating, and extrude using an IIoH extruder with a T-die (manufactured by Ikegai Tekko ■, IS-DA O-ya) at an extrusion temperature of 1LLQ℃.
, a screw rotation speed j Q rpln and a thickness θμ were produced.

Five hours after the start of film formation, the film was sampled, and the bath melting thermal stability was evaluated by counting fish eyes of 10 μm or more using a laser eye (manufactured by Yasuyo Denki ■).

The results are shown in Table 2 below.

Table 1 [Effects of the Invention] The composition of the present invention has extremely good melting thermal stability, and when molded into a molded product, it has excellent mechanical properties, gas barrier properties, and dimensional stability, and molding without problems such as fish eyes. can manufacture products.

Claims (3)

[Claims] (1) (I) Saponified ethylene-vinyl acetate copolymer, (II) The content (μeq/g/polymer) of the terminal carboxyl group (X) and the terminal amino group (Y) has the formula Y≧X+
A resin composition comprising a polyamide resin that satisfies item 5 and (III) an α-olefin ionomer resin. (2) The weight mixing ratio of (I) and (II) is (I)/(I
The resin composition according to claim 1, wherein I)=98/2 to 2/98. (3) The weight mixing ratio of (III) and (I) + (II) is (I
The resin composition according to claim 1 or 2, wherein II)/(I)+(II)=2/98 to 50/50.