JPH04178447A - Resin composition - Google Patents

Abstract

PURPOSE:To obtain a composition suitable for continuously molding packaging materials, having excellent drawing properties, gas barrier properties, hot-water resistance, oil resistance, etc., comprising a saponified ethylene-vinyl alcohol copolymer and a specific polyamide. CONSTITUTION:(A) 60-95wt.% saponified ethylene-vinyl alcohol copolymer having 25-60mol%, especially 25-50mol% ethylene content is blended with (B) 5-40wt.% polyamide having 160-215 deg.C melting point, which is an aliphatic polyamide comprising capramide as a main constituent unit, having a ratio of number of methylene groups and number of amide groups satisfying formula I, wherein an end carboxyl group content X and an end amino group content Y are adjusted to satisfy formula II by using an end modifying agent. The ratio of capramide unit in the component B is 95-55wt.%, especially 90-65wt.%.

Description

Detailed Description of the Invention <Industrial Application Field> The present invention provides a stretchable,
The present invention relates to a resin composition that has excellent gas barrier properties, fFIpk water resistance, oil resistance, impact resistance, etc., and is particularly suitable for continuous molding of packaging materials.

<Prior art> Ethylene-vinyl alcohol co-11 saponified product (hereinafter abbreviated as EVOH) has extremely low oxygen gas permeability, excellent oil resistance, and can be easily formed into transparent molded products using normal melt molding processing methods. From what is obtained, the film,
It is useful as a packaging material for cartons, tubes, plastic containers, etc.

On the other hand, EVOH has drawbacks such as high water permeability due to its hydrophilic nature and lack of hot water resistance, hardness and brittleness with low impact strength, and extremely poor stretchability, which have limited its use. ing. Conventional EVO
As one of the means to improve the above-mentioned drawbacks of H, there is a method of mixing polyamide with EVOH (Japanese Patent Publications No. 44-24277, No. 48-22833, No. 1213-1983).
47 Publication, Special Publication No. 24813, Special Publication No. 1988-
24814 and Japanese Unexamined Patent Publication No. 64-9238). According to this method, the disadvantages of EVOH such as lack of hot water resistance, hardness and brittleness with low impact strength, and extremely poor stretchability can be improved.

<Problems to be Solved by the Invention> However, although the compositions made of EVOH and polyamide used in these have many desirable properties as packaging materials, no special efforts have been made regarding the terminal groups of the polyamide. There are serious drawbacks in practice. The reason is that when EVOH and polyamide are mixed in a molten state, a chemical reaction occurs between the two, and as a result, the viscosity of the mixed composition increases, resulting in a gel with intense coloration.

That is, due to this disadvantageous phenomenon, compositions made of EVOH and polyamide are difficult to continuously mold into films.
It cannot be applied to continuous manufacturing processes for practical products such as notebooks and tubes. Although the mixture of EVOH and polyamide has extremely excellent characteristics as described above, at present it has not been put into practical use due to some fatal flaws. Therefore, the present inventors maintained the EVOH improvement effect of polyamide, and also
As a result of intensive studies to obtain a resin composition that does not exhibit the increase in viscosity during melting as shown by mixed compositions of E and polyamide,
The inventors have discovered that the above object can be achieved when a specific aliphatic copolymer polyamide is selected as the polyamide to be blended into VOH, and thus the present invention has been achieved.

Means for Solving the Problems> The present invention provides a saponified ethylene-vinyl alcohol comonomer with an ethylene content of 25 to 60 mol%, 60 to 95% by weight.
an aliphatic polyamide consisting of 5 to 40% by weight of polyamide and polyamide, in which the polyamide has caproamide as the main structural unit, and the ratio of the number of methylene groups to the number of amide groups satisfies the following formula (I), and an end-adjusting agent is used. The terminal carboxyl group content rX) and the terminal amino group content [Y] were adjusted so as to satisfy the following formula (U), and the melting point was 160 to
The resin composition has a temperature range of 15°C.

5.20≦CH2/NHCO≦750... value ■) [Y]
< [X] +0. 5x l O"5...-(IT
) (However, the units of [X] and [Y] are m017g
・It is a polymer. ) The EVOH used in the present invention has ethylene content of 3125 to 60
Ethylene-vinyl alcohol copolymer with mol%, preferably 25 to 55 mol%, more preferably 25 to 50 mol%, and the degree of saponification of vinyl acetate is not particularly limited, but is 90 mol% or more, preferably 95 mol% or more. It is a saponified product. When the ethylene content is less than 25 mol%, the molding temperature becomes close to the decomposition temperature, making molding difficult. On the other hand, when the ethylene content exceeds 60 mol%, extrudability is good but gas barrier properties are poor. Further, EVOH having a degree of saponification of less than 90% is undesirable because it produces less cracks and pinnar during container molding, but has insufficient dimensional stability and gas barrier properties.

The polyamide used in the present invention is formed by copolymerizing the caproamide component, which is the main component, with another aliphatic polyamide, and has a ratio of the number of methylene groups to the number of amide groups of formula 520≦C
It is an aliphatic polyamide that satisfies 112/NlIC0≦650. The caproamide unit in this copolymer is 95 to
55% by weight, preferably 90-600-60% by weight, preferably 90-650-65% by weight. A copolyamide containing less than 55% by weight of caproamide units is
The effect of improving the stretchability, hot water resistance, impact resistance, etc. of EVOH is small (on the other hand, if the caproamide unit exceeds 951% by weight, the melt molding processing temperature of the mixed composition of EVOH and polyamide becomes high, resulting in a gelled product) This is not preferable because continuous molding becomes difficult due to the generation of carbon atoms and coloring.Other aliphatic polyamides used in the present invention include those having 6 to 12 carbon atoms
aminocarboxylic acids or lactams, carbon atoms 6 to 1
2 dibasic acid and a diamine having 4 to 1 carbon atoms, and nylon 6 is excluded here. The content of other aliphatic polyamides is 5 to 45% by weight,
Preferably 10-40% by weight, more preferably 10-3%
It is 5% by weight. Regarding the concentration of 7-amide groups in the polyamide used in the present invention, the ratio of the number of methylene groups to the number of amide groups (C-2
/IIHcO) is 5.20 to 650, preferably 5.2
It is necessary that the amide group concentration l be within the range of 0 to 6.00, more preferably 530 to 5.80.
There are 5 or more components in the total copolymer! ! It must be introduced at least 1% by weight, preferably at least 10% by weight. This C
If a copolyamide with an M2/NHCO value of less than 5.20 is mixed with EVOH, the mixed composition will gel, making continuous molding over a long period of time difficult. On the other hand, if the CI+2/N[lCO value of the polyamide exceeds 6.50, the amount of caproamide units in the copolymerization will decrease, and the effect of improving the stretchability, hot water resistance, impact resistance, etc. of EVOH will decrease. Undesirable. Examples of copolyamides used in the present invention include nylon 6, nylon 66, nylon 1
1, nylon 12, and nylon 610 copolymers. Especially Ny076/12, Nylon 6/
31゜Nairo 76.66.12, Nairo 76.66.1
The copolymerized nylon of No. 1 is preferred in the present invention. By copolymerizing the polyamide used in the present invention, it maintains the oil resistance, stretchability, toughness, cold resistance, etc. that polyamide has, has excellent J1 hydrothermal properties, and does not exhibit an increase in viscosity during melt molding. The effect is effectively demonstrated. A quaternary copolymerization or higher is not preferred because hot water resistance is poor. However, a small amount of other quaternary or more components may be copolymerized or other polyamide components may be blended as long as the effect is not impaired. Of course, two or more types of polyamides used in the present invention may be blended. The melting point of the polyamide used in the present invention is 160 to 215°C, preferably 165°C.
~215°C, more preferably 1゛65~210°C. When the melting point is below 160°C, extrudability is good, but fl
It is not preferred because it has poor aqueous properties. On the other hand, if it is 215° C. or higher, the melting point will be close to that of nylon 6 (11117), so the processing temperature will be too high, and continuous molding will become difficult due to coloring and generation of gelatinized materials during melt molding, which is not preferable. The polyamide used in the present invention has carboxyl/
The amount of each terminal carboxyl group and amino group must satisfy the formula (I1). That is, in polyamides obtained by polymerizing lactams, aminocarboxylic acids, dibasic acids, and diamines, the content of terminal carboxyl groups in the molecule is 114! ! ! The content of the terminal amino group is adjusted by the agent to be greater than the content of the terminal amino group,
Content of the above carboxyl group [X] (mol/g・
polymer) and amino group content [Y] (mo I
7g/polymer) 1m [Y] < [X co+o, sx+
os, preferably [Y] < [X] +O87XI
It is necessary that the relational expression O-5 holds true. and,
Desirably amino group-containing fll [Y] (mo I
/g・polymer) as the absolute value of 7 x 10-5mo
l 7g/polymer or less, preferably 5x 10-s
mo 17g-polymer or less, more preferably 4xl
More preferably, it is less than O-5 mol/g of polymer. If there are too many terminal amino groups, there will be no effect of improving continuous film formation, which is not preferable.

On the other hand, although having a small number of terminal amino groups is preferable from a usage standpoint, it poses difficulties in resin production, so lXl0-5m o
It is a good idea to limit the amount to 1/g polymer. Although not particularly specified, the absolute value of carboxyl group-containing [X] (mol/g polymer) is preferably 10XIO-'mol/g polymer or less, preferably 7XIO-5 mol/g polymer, More preferably, 5xt.

-'mol/g·boria or less is suitable. The above terminal regulator is not particularly specified, but usually has 2 to 2 carbon atoms.
23 carboxylic acid and a diamine having 2 to 20 carbon atoms are used. Specifically, as a carboxylic acid having 2 to 23 carbon atoms,
Aliphatic monocarboxylic acids such as acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, enanotic acid, caprylic acid, undecacic acid, lauric acid, stearic acid, oleic acid,
/Alicyclic monocarboxylic acid such as Kurohebyusancarboxylic acid/
Aromatic monocarboxylic acids such as benzoic acid, ethyl benzoic acid, and phenylacetic acid; and diamino acids having 2 to 2 degrees of carbon atoms include ethylene dianino, trimethylene diamine, tetramethylene diamino, and be/tamethylene 7-noamine. , hexamethylenediamine, heptamethylenenoamino, octamethylenediamine, nonamethylenediamino, decamethylenediamine/, undecamethylenenonoamino, dodecamethylenediamine, tridecamethylenediamine, hexadecamethylenediamine, octadecamethylenediamine. Examples include alicyclic diamines such as aliphatic diamino, chlorohexane diamino, methylchlorohexanoamine, and aromatic diamines such as quinlene diamine.

In addition to the above monocarbo/acids, malonic acid, succinic acid, glutamic acid, anopic acid, pimelic acid, speric acid, azelaic acid 1. aliphatic nocarboxylic acids such as sepanonic acid, unodecadioic acid, dodecanoic acid,
Nocarboxylic acids such as alicyclic nocarboxylic acids such as 1°4-7 chlorohexane nocarboxylic acid, aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, and phthalic acid can also be used or used in combination.

The amount of the terminal regulator used is not particularly limited, but the amount of carboquine groups is usually 0.0% less than the amount of amino groups. 1~+8 (
meq, /mol), preferably 0.2 to +
8 (meq, /mol), more preferably in an excess of 02-15 (meq, /mol). The amount of terminal regulator used is 0. 1 (meq,
If it is less than 15 (meq, /mol), no effect of improving continuous film formation will be observed, and if it is more than 15 (meq, /mol), the degree of polymerization will increase slowly, which is unfavorable in terms of production. The degree of polymerization of the polyamide used here is not particularly limited, but according to JIS K
6810 at a concentration of 1% in 98% sulfuric acid at 25° C. from 1.7 to 4.0, preferably from 2.0 to 4.
,0, more preferably from 2.0 to 3.5. The method of forming the copolyamide used in the present invention is not particularly limited, and melt polymerization, interfacial polymerization, solution polymerization, bulk polymerization, solid phase polymerization, and a combination of these methods can be used. Usually, melt polymerization is preferably used. The amount of polyamide added to EVOH is 5 to 40M%, preferably 7 to 35%, more preferably 10 to 30%.

If the amount added is less than 51% by weight, the effect of improving moldability is not sufficient and cracks and unevenness are likely to occur. On the other hand, 4011% by volume
If this is the case, the gas barrier properties will be greatly reduced and the container will not be usable as a gas barrier container. The method of blending EVOH and polyamide is not particularly limited, but there is a method of tri-blending EvoH and polyamide and drying it into pellets using a single-screw or twin-screw extruder with sufficient cross-mixing force. The composition of the present invention is mainly used for packaging materials such as films, containers, tubes, and plastic containers, but it may of course be used for other purposes as well. When molding the composition of the present invention, ordinary extrusion molding, blow molding, injection molding, etc. can be applied, and in any case, no gelation occurs for a long period of time.
Stable continuous molding is possible. For example, in order to produce a single film from the composition of the present invention, it is usually first extruded in a molten state from a T-die head of an extruder, and then a known casting method, typically an air knife casting method, an electrostatic application method, An unstretched film is obtained by cooling and solidifying on a casting drum using a method such as a vacuum chamber method. Subsequently, this unstretched film is stretched in at least one direction.

Usually, sequential biaxial stretching in the order of longitudinal stretching and transverse stretching is preferably used in terms of productivity. Of course, unstretched or simultaneous biaxial stretching is also possible, and the stretchability is extremely good. Further, it is preferable to perform heat treatment after stretching in order to maintain dimensional stability and hot water resistance, and tension heat treatment or relaxation heat treatment is effective. The packaging material made of polyamide used in the present invention is
It has excellent oil resistance, transparency, gas barrier properties, impact resistance, and especially hot water resistance, and is highly valuable when used alone, but it can be layered with other thermoplastic resins to impart even more film properties. is possible. The film properties of such laminated films vary depending on the type of thermoplastic resin laminated. For example, laminating polyolefin resin can significantly reduce water vapor permeability, and laminating polyester can significantly improve heat resistance and prevent high temperatures and tort. It can withstand processing well. In the case of these laminated films as well, it is preferable to stretch them under appropriate conditions to take advantage of their good stretchability. In addition to the same advantages as the above-mentioned films, the net formed from the composition of the present invention has 7-
It has the advantage of excellent deep drawing formability, and when forming tubes and hollow molded products (containers) by blow molding, biaxial stretch blow molding is possible, improving the dimensional stability and creep resistance of molded products. This provides the advantage of superior performance. In addition, when molding a /-t or blow-molded product, other thermoplastic resins can be laminated as in the case of the above-mentioned film. It should be noted that other components such as heat stabilizers, crystal nucleating agents, antioxidants, lubricants, fillers, plasticizers, etc. may be added to the composition of the present invention within a range that does not impair its properties, moldability, etc. I can do it.

The present invention will be explained in further detail by giving examples below.

In addition, each evaluation was measured according to the method described below.

(I) Oxygen permeable film was heated to 0XY-T under the conditions of 20°C and 100% RH.
RANloo (Modern Controls
(manufactured by). Unit: l/-t: c
c/m”24hr and thickness O, per 1mm: cc
/m'・24hr10. It is 1 mm.

(2) Boil Test A film (I00 μm thick) was boiled (held in boiling water for 30 minutes) and then taken out and changes in the film were observed.

The evaluation was as follows: No change before and after treatment; 20; film edges partially melted or poor flatness; Δ; film melted; ×;

(3) The state of the stretchable film was observed. Evaluation is uniformly stretched,
Good transparency, O1: Some stretching unevenness: △, film tearing or stretching unevenness occurred during stretching, resulting in poor stretching.

(4) Melt-extrude the composition with thickening gel properties from an extruder to continuously obtain 200μ
An unstretched film was produced, and after the start of film formation, the time until countless gelled substances appeared on the film surface and film formation became impossible was measured.

Note that parts and percentages in the examples indicate parts by weight and percentages by weight, respectively.

(5) Measurement of terminal group amount Carboquine groups were measured by dissolving polyamide in benzyl alcohol and titrating with 0.05N potassium hydroxide. Amino groups can be obtained by dissolving polyamide in phenol and adding 0.0
It was measured by titration with 5N-hydrochloric acid.

Examples 1 to 8 For EVOH having an ethylene content of 33%, a saponification degree of 99%, and a melting point of 170°C, a terminal regulator (benzoic acid, stearic acid, oleic acid, hexamethylene diamine) was added to the following polyamides A to C. The added ingredients were blended in the amounts shown in Table 1, and the evaluation results are shown in Table 1.

Polyamide A (nylon 6/12)... Copolyamide polyamide obtained by melt polymerizing ε-caprolactam and aminododecanoic acid Polyamide B (nylon 6/I+)... Copolyamide polyamide obtained by melt polymerizing ε-caprolactam and aminoundecanoic acid C (nylon 6/66/I2)...ε
- A copolymerized polyamide obtained by melt polymerizing caprolactam, an equimolar salt of hexamethylene diamine and anopic acid, and aminododecanoic acid.

Polyamide D (nylon 6/66/II)...
A copolymerized polyamide obtained by melt polymerizing ε-caprolactam, an equimolar salt of hexamethylene diamine and anopic acid, and aminoundecanoic acid.

From Table 1, it can be seen that each composition did not generate gelled substances in the film even after continuous molding for 30 hours or more, and the film had excellent flatness and transparency, and had good stretchability and gas barrier properties.

Comparative Example 1 The same evaluation was performed on the polyamide of Example 1 to which the terminal 2 stabilizer was not added, and the results are shown in Table 2. In terms of performance, you can get something that is satisfactory to some extent, but at the end 2!2
No improvement in continuous film forming property was observed compared to the case in which the agent was added.

Comparative Example 2 The polyamide of Example 3 to which 9 (meq/mo+) hexamethylene diamine was added as an end regulator was similarly evaluated, and the results are shown in Table 2. Although the performance was satisfactory to a certain extent, the effect of improving continuous 'JAR properties was not observed as in the case of those containing a large number of carboxyl/ru groups.

Comparative Examples 3 to 6 Polyamides of Examples whose blending amount in EVOH is out of the range of the present invention, aliphatic polyamide CH2/NHC
Those in which the O ratio or the amount of copolymerization of caproamide units deviated from the range of the present invention were evaluated in the same manner, and the results are shown in Table 2. In the film containing a large amount of nylon (Comparative Example 3), the gas barrier properties of the unstretched film were inadequate, and in the film containing a small amount of nylon (Comparative Example 4), the stretchability was inadequate. In the case where the CF(2/NHCO ratio was small (Comparative Example 5), a gelled substance was generated on the film 7 hours after the start of film formation, making it impossible to form a film.The case where the CH2,·NHCO ratio was large (Comparative Example 5) Example 6) had inadequate hot water resistance and oxygen permeability.

<Effects of the Invention> The resin composition of the present invention has excellent gas barrier properties, stretchability,
Moreover, it is a resin that has the characteristic of suppressing gelation during continuous molding over a long period of time.

Here, the excellent gelation suppressing effect is thought to be due to the low melting point of the polyamide used in the present invention, which allows the molding temperature to be lower than usual, and also because the end-to-end formulation suppresses the reactivity of the ends.

Claims (1)

[Scope of Claims] Consisting of 60 to 95% by weight of a saponified ethylene-vinyl alcohol copolymer having an ethylene content of 25 to 60 mol% and 5 to 40% by weight of polyamide, the polyamide having caproamide as its main structural unit, An aliphatic polyamide in which the ratio of the number of methylene groups to the number of amide groups satisfies the following formula (I), and the terminal carboxyl group content [X] and the terminal amino group content [Y] are as follows ( II)
Melting point is 160-21, adjusted to satisfy the formula
A resin composition having a temperature range of 5°C. 5.20≦CH_2/NHCO≦6.50...( I
)[Y]<[X]+0.5×10^-^5...(II)
(However, the units of [X] and [Y] are mol/g polymer.)