JPH0299546A - Saponified ethylene-vinyl acetate copolymer-based resin composition - Google Patents

Abstract

PURPOSE:To obtain a resin composition, consisting of a saponified ethylene-vinyl acetate copolymer and a fluorine-based compound containing (CF2), excellent in thermal stability and long runnability in melt molding and capable of providing molded products excellent in quality. CONSTITUTION:A resin composition obtained by, e.g., adding (B) a fluorine-based compound containing (CF2), e.g., fluororuber (e.g., copolymer of vinylidene fluoride and trifluoroethylene) or fluorine-based surfactant (e.g., fluoroalkylcarboxylic acid) having a perfluoroalkyl group, in an amount within the range of 0.0005-20 pts.wt., preferably 0.005-10 pts.wt. to (A) 100 pts.wt. saponified ethylene-vinyl acetate copolymer with 20-80mol%, preferably 25-70mol% ethylene content and >=90%, preferably >=97% saponification degree of the vinyl acetate part in polymerizing the component (A) or melt mixing the components (A) with (B).

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Industrial application field The present invention is an ethylene-vinyl acetate compound that has excellent thermal stability and long-run properties during melt molding, and can yield molded products of extremely good quality. Saponified polymer (hereinafter referred to as EV
(abbreviated as OH) type resin composition.

(2) Conventional technology EV OH is one of the resins with the best gas barrier properties among the thermoplastic resins currently on the market.
It is widely used in various packaging materials including food products, multilayer laminated films, containers, bottles, mechanical parts, parts for electrical appliances, etc. However, when it is directly melt-molded or melt-formed, the viscosity changes significantly. Not only is it difficult to mold stably (poor thermal stability), but the molded product is colored and many gels and fish eyes occur, significantly reducing its commercial value. In addition, there are many problems such as poor long-run performance due to resin melt adhering to the inner wall of the extruder, making it impossible to perform continuous melt molding over a long period of time, and the extruder having to be dismantled frequently to clean the screw. . Therefore, many measures have been taken in the past. For example, it was reported in Japanese Patent Publication No. 46-3766 that improvements could be made by incorporating phosphoric oxides.
Publication No. 4, JP-A-48-25048, JP-A-51
It is described in Japanese Patent Laid-open No. 88544-88544, Japanese Patent Application Laid-open No. 88545-1983, and the like. In addition, it was reported in JP-A No. 5 that it could be improved by adjusting the pH by blending an acid and an alkali metal salt.
It is described in JP-A-2-954, JP-A-52-955, JP-A-52-956, JP-A-52-957, and the like. In addition, improvements can be made by blending a hydrotalcite compound in Japanese Patent Application Laid-Open No. 80-1990.
40, JP-A-60-238345, JP-A-62-15243, JP-A-62-15246, and the like.

(3) Problems to be solved by the invention However, although these measures can improve part of the above problems, they cannot improve all the problems at once, and in the case of certain types of additives, Some of them are inappropriate in terms of food hygiene.

Therefore, the invention of an EVOH composition that has good thermal stability, excellent long-run properties, and good quality of molded products is an important issue in melt molding.

When EVOH is heated in air under static conditions, it becomes colored yellow or brown, and its viscosity decreases due to main chain scission. Furthermore, heating in an oxygen-free atmosphere such as nitrogen or vacuum can suppress coloring and main chain scission reactions, but on the contrary, crosslinking reactions occur and the viscosity increases.

As a result of various studies conducted by the present inventor, it has been found that each reaction proceeds at an accelerated rate in a molten crosstalk state.

It is thought that these reactions occur simultaneously in an extruder during actual melt molding of EVOH.

(4) Means for solving the problems As a result of various studies in order to solve all of the problems mentioned above, the inventors of the present invention have developed a solution to E V OH (CF2
) The EVOH resin composition obtained by blending a fluorine-based compound containing It has become possible to suppress the adhesion of molten matter. As a result, the viscosity change during melt molding is small (.

The present inventors have discovered that stable production is possible (good thermal stability), excellent long-run properties, and extremely good quality molded products with little coloring, gel, or fish eyes can be obtained, and the present invention has been completed.

The fluorine-based compounds containing EVOH and (CF2) used in the present invention will be explained below.

Examples of the EVOH used in the present invention include those having an ethylene content of 20 to 80 mol%, preferably 25 to 70 mol%, and a saponification degree of the #acid vinyl moiety of 90 mol% or more, preferably 97 mol% or more. . If the ethylene content is less than 20 mol%, the melting point of the resin will become high and approach the decomposition temperature, making melt molding and film formation difficult; on the other hand, if it exceeds 80 mol%, not only will the gas barrier properties deteriorate, but the The effects of the invention are not very noticeable. Furthermore, if the degree of saponification is less than 90 mol%, gas barrier properties, oil resistance, and water resistance are significantly reduced, resulting in poor practicality.

An example of the fluorine-based compound containing (CF2) used in the present invention is fluororubber.

Examples of fluorine rubber include copolymers of vinylidene fluoride and ethylene trifluoride, copolymers of vinylidene fluoride and propylene trifluoride, copolymers of vinylidene fluoride and propylene hexafluoride, and copolymers of vinylidene fluoride and propylene hexafluoride. Vinylidene, propylene hexafluoride, and ethylene tetrafluoride terpolymer.

Examples include, but are not limited to, vinylidene fluoride copolymers such as tetrafluoroethylene and propylene, and fluorinated silicone rubbers in which fluorinated alkyl groups are introduced into the siloxane side chains.

Further, other examples of fluorine-based compounds containing (CF2) used in the present invention include -killing, CF3 (CF2
) n A fluorine-based surfactant having a perfluoroalkyl group can be mentioned. Examples of fluorine-based surfactants include 1, fluoroalkylcarboxylic acid, disodium N-perfluorooctanesulfonylglutamate, 3-
Sodium (fluoroalkyloxy)-1-alkylsulfonate, Sodium 3-(ω-fluoroalkanoyl-N-ditylamino)-1-propanesulfonate, N
-(3-(perfluorooctanesulfonamido)propyl)-N, N-dimethyl-N-carboxymethylene ammonium betaine, perfluorooctane sulfonic acid ether amide, perfluoroalkyl sulfonic acid @ (Li, Ni, Na), N-propyl-N-(2-
Hydroxyethyl) perfluorooctane sulfonamide, perfluoroalkyl sulfonamide propyl trimethyl ammonium salt, perfluoroalkyl-N-
Ethylsulfonylglycine salt, bis(N-perfluorooctylsulfonyl-Nethylaminoethyl) phosphate
, monoperfluoroalkylethyl phosphate, etc., but are not limited thereto.

EVOH100 of fluorine-based compounds containing these (CF2)
The amount to be added is preferably 0.0005-20 parts by weight, preferably 0.005-10 parts by weight. If the amount is less than 0.0005 parts by weight, the above effects will not be achieved, and if it exceeds 20 parts by weight, the gas barrier properties will decrease and the moldability will also deteriorate.

The means for obtaining the composition of the present invention by blending a fluorine-based compound containing (CF2) with EVOH include adding it during polymerization of ethylene-vinyl acetate copolymer, adding it during saponification reaction, or extrusion. There are methods such as melt mixing using a kneader such as a kneader, solution mixing by dissolving in a common solvent, or mixing using a Henschel mixer, tumbler, etc.

The resin composition of the present invention can be molded into any molded product such as a film, sheet, tube, or bottle using any melt molding method such as injection molding, compression molding, or extrusion molding. The extrusion temperature during molding is appropriately selected depending on the properties of the extruder, the molecular weight and blending ratio of the resin, and in most cases is in the range of 170°C to 300°C.

In addition, when the resin composition of the present invention is used as a single layer of a laminate, examples of the partner resin include low density polyethylene, medium density polyethylene, high density polyethylene, polypropylene,
Homopolymers of olefins such as polybutene and polypentene, ethylene-vinyl acetate copolymers, ionomers, copolymers of ethylene-α-olefins (α-olefins having 3 to 20 carbon atoms), and ethylene-(meth)acrylic acid copolymers. Polymer.

Ethylene-(meth)acrylic acid ester copolymer.

Binary copolymers such as ethylene-glycidyl (meth)acrylate copolymers, ethylene-(meth)acrylic acid (ester)-unsaturated carboxylic acid copolymers, and ethylene-vinyl acetate-glycidyl (meth)acrylate copolymers Polyolefin resins in a broad sense, such as terpolymers such as olefins, or those obtained by graft-modifying individual or copolymers of these olefins with unsaturated carboxylic acids or esters thereof.

Polyester fruit trees/fats, polyamide resins, copolymer polyamide resins, vinyl chloride resins, vinylidene chloride resins, acrylic resins, acrylamide resins, vinyl ester resins, polyester elastomers, polyurethanes, polycarbonates, chlorinated polyethylene resins , chlorinated polypropylene resin, etc., but are not limited to these.

The layer structure is that the E V OH resin composition of the present invention is A (A1
, A2, ...), and the resin on the other side is P(PL, P 2
．． ), when the adhesive resin used as necessary is D, not only A/P2N structure but also A/PEA,
P/A/P, PL/P2/A, P/
Al/A2゜A/P/A/P/A, A, 2/Al
/P/AI/A2, A/D/P, A/D/P/
D/A, P/D/A/D/P, A/D/P/
Any configuration such as D/A/D/P/D/A is possible. In addition, the other resin may be blended with either or both of A and P in Section 1, or a resin that improves the adhesion between the two resins may be blended.

Additives such as antioxidants, 2I: external radiation absorbers, plasticizers, antistatic agents, colorants, lubricants, fillers, etc. are added to the composition of the present invention to the extent that the effects of the present invention are not inhibited. be able to.

After melt molding, the molded product is subjected to heat treatment, cooling treatment,
Rolling processing, -axis or two-wheel stretching processing, printing processing, dry lamination processing, solution or melt coating processing, bag making processing,
It is possible to perform search processing, box processing, tube processing, sprint processing, etc.

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

Hereinafter, the term "part" is expressed on a heavy jk basis unless otherwise specified.

[EVOHI A-1 used: ethylene content 32 mol%, degree of saponification of vinyl acetate component 99 mol%, melt index (Ml) at 230°C 5.8 r, 710 m1nA-2:
Ethylene content 43 mol%, saponification degree of vinyl acetate component 9
9 mol%, melt index (MI) at 230°C
21 g/10 m1n [Fluororubber used 1 (a) Hypanyritene fluoride - propylene hexafluoride - viscosity 65 (b) Hypanyritene fluoride - propylene hexafluoride copolymer, viscosity based on a Fuchfeelto viscometer
1400-3100 (poise) [Fluorinated surfactant used I
Sodium furkylsulfonate [Thermal stability during molding used in Examples and Comparative Examples.

! ! Evaluation method of An adhesion status and quality of molded products] - Change in viscosity during molding (thermal stability) Melt and mix in air and nitrogen at 200°C and 40 rpm using Labo Plasto Mill (manufactured by Toyo Seiki). Evaluation was made from the ratio of torque values 5 minutes after kneading and 30 minutes after kneading (30 minutes t & 15 minutes later).

・Resin adhesion status (long run properties) Laboplasto mill in nitrogen at 200℃, 40 rpm
The mold releasability of the resin from the rotor after melt-kneading for 30 minutes was evaluated on a three-grade scale of 1 (good) to 3 (bad).

- Molded product gt (coloring) In air at 200° (:, 4 O
rpm. After melt-kneading for 30 minutes, the change in color of the resin was observed.

・Quality of molded product (gel, VHS eye) 20mmφTd
Gel in a film formed with an ie molding machine.

Using a magnifying glass, the following 5-stage β-bamboo evaluation was performed on the number of eyelids.

1: O-5 (pieces/100 cmz) 2: 5-10 3: 11-50 4: 51-200 5: 201 or more Examples 1-7 The above E V O I- (100 parts by weight as shown in Table 1) Regarding the pellets containing fluorine-based compounds in the following proportions.

As a result of the above evaluation, thermal stability, long-run performance, and quality of molded products were improved.

The results are shown in Table 1.

Comparative Examples 1 to 3 The above evaluations were conducted on pellets prepared by blending various additives in the blending ratios shown in Table 2 with 100 parts by weight of the EVOH.

The results are shown in Table W2.

(The following is a blank space) (6) Effects The resin composition of the present invention is mainly useful for molded products such as food packaging, various packaging films, containers, bottles, food trays, sheets, and various equipment parts. It can be used for various purposes such as extrusion coating of paper or plastic.

Claims (3)

[Claims] (1) Ethylene consisting of a saponified ethylene-vinyl acetate copolymer with an ethylene content of 20 to 80 mol% and a degree of saponification of vinyl acetate units of 90 mol% or more, and a fluorine-based compound containing (CF_2) −
Saponified vinyl acetate copolymer resin composition. (2) The saponified ethylene-vinyl acetate copolymer resin composition according to claim 1, wherein the fluorine compound is a fluorine rubber. (3) The ethylene compound according to claim (1), wherein the fluorine-based compound is a fluorine-based surfactant having a perfluoroalkyl group.
Saponified vinyl acetate copolymer resin composition.