JPS6215246A - Resin composition - Google Patents

Abstract

PURPOSE:To obtain a resin composition having improved extrudability and long-run property in molding and remarkably improved production efficiency and quality, by compounding specific amounts of a specific composite compound and a higher fatty acid metal salt to a specific saponified ethylene-vinyl acetate copolymer. CONSTITUTION:A saponified ethylene-vinyl acetate copolymer having an ethylene content of 20-80mol% and a saponification degree of >=90mol% at the vinyl acetate unit is compounded with (A) 0.005-5(wt)%, preferably 0.08-3% compos ite compound of formula (M is Mg, Ca, etc.; E is CO3 or HPO4; x, y and z are positive number; a is 0 or positive number) and, if necessary, (B) 0.005-2%, preferably 0.08-1% 10-22C higher fatty acid (e.g. lauric acid) metal salt (e.g. sodium salt).

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a saponified ethylene-vinyl acetate copolymer resin composition which has significantly improved production efficiency and quality.

[Prior art 1 Saponified ethylene-vinyl acetate copolymer (hereinafter abbreviated as EVO) has excellent mechanical properties such as impact strength and tensile strength, solvent resistance, chemical resistance, gas barrier properties such as oxygen, It has excellent fragrance retention, oil resistance, and even non-static properties, so it is used in various packaging materials including food, multilayer laminated films, containers, bottles, as well as engineering parts for mechanical parts and electrical appliances. It is widely used in plastics, etc.

[Problem to be Solved by the Invention 1] However, compared to thermoplastic resins such as polyethylene and polypropylene, EVOH has inferior production efficiency during melt molding, that is, the amount of resin discharged from the nozzle per unit time is low. There is a problem unique to EVOH. In other words, normally, the theoretical discharge amount per screw revolution and the actual discharge amount do not necessarily match, but in the case of various thermoplastic resins other than EVOH such as polyethylene and polypropylene, the discharge amount is 80% or more of the theoretical value. In EVOH, a discharge amount can be expected to be only about 50 to 60% of the theoretical value. Although the cause of this is not clear, it is useful for molding companies to efficiently improve EVOI-
It is an earnest request to perform molding of 1.

The problem of long-run performance during melt molding of EVOH, that is, the problem that continuous melt molding cannot be performed for a long period of time due to the resin melt adhering to the inner wall of the extruder, has conventionally been improved by blending various additives. Proposed (for example, Japanese Patent Publication No. 48-32074, etc.)
However, improvement in long-run performance does not necessarily directly lead to an increase in discharge amount, and in conventional methods, even if long-run performance improves, the discharge amount does not change much.

Of course, it goes without saying that if good values can be obtained in both long-run performance and discharge amount, better production efficiency will be achieved.

[Means for Solving the Problems] However, as a result of various studies in order to solve the above-mentioned problems, the present inventors found that the ethylene content was 20 to 80 mol%, the degree of saponification of the vinyl acetate moiety was 90 mol % or more of EVOH has the general formula % formula % (where M is M g t Ca or Zn, E is CO, or HPO, ×.

An EVOH resin composition containing a composite compound (P) represented by (y, z are positive numbers, a is 0 or a positive number) can significantly improve the discharge amount, and furthermore, We have discovered that when the composite compound (P) and a metal salt of a higher fatty acid having 10 to 22 carbon atoms (Q) are used together, even better production efficiency can be achieved by increasing the discharge amount and improving long-run performance. He has completed his invention.

Furthermore, when the molded product obtained from the resin composition of the present invention is made into a film, for example, it can be expected to have extremely good quality with less blocking, which is also an extremely important effect from an industrial perspective. be.

Hereinafter, the resin composition of the present invention will be described as EVOH1 composite compound (P
) and metal salts of higher fatty acids (Q) will be explained respectively.

First, the EVOH used in the present invention has an ethylene content of 20 to 80 mol%, preferably 25 to 70 mol%,
Examples include those having a saponification degree of vinyl acetate moiety of 90 mol% or more, preferably 97 mol% or more. If the ethylene content is less than 20 mol%, thermal stability will be poor and melt moldability will be reduced, and if the ethylene content exceeds 80 mol%, not only will the oxygen barrier property be reduced, but the composition will become close to that of polyethylene, resulting in a lower discharge rate. Since the problem of a decrease in the amount of water hardly occurs, there is no need for the composite compound (P).

If the degree of saponification of the vinyl acetate portion is less than 90 mol%, thermal stability will be poor, and oxygen barrier properties, oil resistance, water resistance, etc.
It is impractical because its physical properties deteriorate. In addition to ethylene and vinyl acetate (or saponified vinyl alcohol), EVOH in the present invention includes unsaturated carboxylic acids or esters or salts thereof, unsaturated sulfonic acids or salts thereof, (meth)acrylamide, (meth)acrylamide, and (meth)acrylamide. It may contain a small amount of about 10 mol % or less of a third component such as α-olefin such as acrylonitrile, propylene, butene, a-octene, and a-octadecene, and a vinyl ester other than vinyl acetate.

The biggest feature of the present invention is that M x A
1y(OH)2X+35+-22(E)Z-aH2
0 (wherein M is M g *Ca or Zn, E is COI or HPO, X.

FEZ is a positive number, and a is 0 or a positive number). Such a composite compound includes Mg4. sA 12(OH),,CO3・3,5H
20゜M85A12(OH)14cO3・4H20゜M
gaA 12(OH)16c Ox ' 4 H2Or
MgeA +2(OH)20C○3-5H20゜M g
+. A I2(OH)2□(C○,)2・4H20°Mg6A +2(OH)+6HP O,・4H20.

CagAI2(OH), 6CO, -4H20゜Zn5A
+5(OH)16CO3・4 H20.

Examples include. Also, not limited to the above, for example, Mg2A
l(o H)-・3H20 The chemical formula is not clearly shown, such as a part of OH in it being replaced with CO3 or HPO, or even the crystal water has been removed (a=O). can be expected to have the same effect. In particular, among these compounds, the compound in which M is Fvf and A is CO3 shows the most remarkable effect. The amount of the composite compound (P) to be blended with EVOH is not particularly limited, but is preferably 0 to 5% by weight.
．． 08 to 3% by weight. If it is less than 0.005% by weight, the effect of the present application of improving production efficiency cannot be obtained, and if it is less than 5% by weight.
Even if they coexist in excess of 20%, no effect can be expected considering the amount, and it is not economical.

When a metal salt of a higher fatty acid having 10 to 22 carbon atoms (Q) is used in combination with the composite compound (P), the long-run performance is improved in addition to the effect of increasing the discharge amount, so that the production efficiency becomes even more excellent.

Examples of such higher fatty acids (Q) include lauric acid, tridecylic acid, myristic acid, pentadecylic acid, balmitic acid, heptadecylic acid, stearic acid, nonadecanoic acid, etc., and metal salts include sodium salt, potassium salt, etc. Alkali metal salts, magnesium salts, calcium salts,
Alkaline earth metal salts such as barium salts and also zinc metal salts are used. Among these, metal salts of stearic acid are by far the most effective. EVOH of the metal salt (Q)
The blending amount is usually in the range of 0.005 to 2% by weight, more preferably 0.08 to 1% by weight. If it is less than 0.005% by weight, no effect can be obtained, while if it exceeds 2% by weight, it is not only economically disadvantageous but also tends to lower production efficiency, which is not desirable.

The above complex compound (P) or it and higher fatty acid metal salt (
Q) is added and blended by mixing EVOH powder or pellets with a Henschel mixer, tumbler, etc. Thereafter, any suitable means may be employed, such as supplying the blend to an extruder and subjecting it to the desired molding as it is, or once pelletizing it and subjecting it to the desired shaping.

The temperature conditions during melt molding are approximately 160 to 260
It is desirable to set it to °C. During molding, reinforcing materials such as glass-filled WL fibers and carbon fibers, low molecular weight polyethylene, low molecular weight polypropylene, paraffin, amide type, ebony type lubricants, fillers, coloring agents, stabilizers, foaming agents, etc. are used as necessary. Additives may also be appropriately added.

Further, during melt molding, a suitable amount of a thermoplastic resin for modification can be added within a range that does not impair the excellent properties of EVOH.

Such thermoplastic resins include various types of high-density, medium-density, and low-density polyethylene, polypropylene, polybutene, polypentene homopolymers, ethylene-propylene copolymers, ethylene or propylene as a main component, 1-butene,
A copolymer with an a-olefin having about 2 to 20 carbon atoms such as 1-hexene, and an olefin-vinyl acetate copolymer having a composition relatively close to that of a polyolefin in which the content of olefin such as ethylene or propylene is 90 mol% or more. Polymers, various polyolefin resins such as olefin-(meth)acrylic acid ester copolymers, graft-modified polyolefins obtained by graft-modifying any of them with unsaturated carboxyl groups, polyamides such as nylon-6 and nylon-6,6 resin, vinyl chloride resin, vinylidene chloride resin,
Acrylic resin, acrylic 7mide resin, styrene resin, vinyl ester resin, polyester resin and polyester elastomer, polyurethane elastomer,
Any material such as polycarbonate, chlorinated polyethylene resin, chlorinated polypropylene resin, etc. can be used.

As the melt molding method, any molding method such as injection molding, compression molding, extrusion molding, etc. can be adopted. Among these, examples of extrusion molding methods include the T-Guy method, blow molding method, vibrator extrusion method, linear extrusion method, profile die extrusion method, and inflation method. The shape of the molded product can be arbitrary, and not only pellets but also films, sheets, tapes, bottles, pipes, filaments, extrusions with irregular cross sections, etc., and multilayer laminates of these and other resins are also important.

In the case of lamination, the mating resins include low density polyethylene, medium density polyethylene, high density polyethylene, ethylene-vinyl acetate copolymer, ionomer, ethylene-a-
Olefin (a-olefin with 3 to 20 carbon atoms) copolymer, ethylene-acrylic acid ester copolymer, polypropylene, fluoropylene-α-olefin (with 4 carbon atoms)
~20 a-olefins) copolymers, homopolymers or copolymers of olefins such as polybutene and polypentene, or homopolymers or copolymers of these olefins graft-modified with unsaturated carboxylic acids or esters thereof, etc. in a broad sense. Polyolefin resin, polyester resin, polyamide resin, copolyamide resin, vinyl chloride resin, vinylidene chloride resin, acrylic resin, acrylic 7mide resin, vinyl ester resin, polyester resin, and polyester elastomer, Examples include polyurethane elastomer, polycarbonate, chlorinated polyethylene resin, and chlorinated polypropylene resin.

It is also possible to coextrude saponified ethylene-vinyl acetate copolymers with different compositions.

The layer structure is that the EVOH resin composition layer of the present application is A (A,,
A2. .

6. ), the thermoplastic resin layer is B(B,,B2.,,,),
When the adhesive layer provided as necessary is C, if it is in the form of a film, sheet, or bottle, it will not only have a two-layer structure of A/B, but also A, / B / A% B / A / B, B, /B2/A,
B/A, /A2, A/B/A/B/A-
A2/A1/B/A,/A2,A
/C/B, A/C/B/C/A, B/C/A/C/B,
Any configuration such as A/C/B/C/A/C/B/C/A is possible, and if it is filament, A and B are bimetal type, core (A) - sheath (B) type, core Any combination such as (B)-sheath (A) type or eccentric core-sheath type is possible. or,
Blend the other resin into either or both of the above A and B
Or, a resin may be added to improve the adhesion between the two resins.

Molded products after melt molding, coextrusion molded products, and melt coated molded products are subjected to heat treatment, cooling treatment, rolling treatment, -axial or biaxial stretching treatment, printing treatment, dry lamination treatment, solution or melt coating treatment, and manufacturing as necessary. Bag processing, search box 1) processing, box processing, tube processing, split processing, etc. can be performed.

[Effect] Thus, by using the resin composition of the present invention, the discharge amount during molding is significantly improved, which not only greatly contributes to improving production efficiency, but also reduces the amount of foreign matter (
The amount of contamination (carbonized resin) is also reduced, and the resulting molded product, for example, can be a film of stable quality with less blocking and fish eyes.

Such an effect greatly affects the quality of a multilayer structure molded product using the resin composition of the present application, so its usefulness is extremely large.

1 Effect J The resin composition of the present invention is mainly useful for molded products such as various packaging films including food packaging, containers, bottles, food trays, and various equipment parts. Of course, it can also be used for various purposes such as extrusion coating of paper or plastic.

[Example 1] Next, the composition of the present invention will be further explained by giving an example. Hereinafter, "parts" are expressed on a weight basis unless otherwise specified.

Shisato Tamami J Shiitocho (A-1): Ethylene'&t 31 mol%, degree of saponification of vinyl acetate component 99.1 mol%, at 210''C (
Same conditions below) Melt index (Ml) 4.0 (A-2): Ethylene content 25 mol%, degree of saponification of vinyl acetate component 99.2 mol%°, Ml 3.6 (A
-3): Ethylene content 55 mol%, degree of saponification of vinyl acetate component 98.3 mol%, MI 25 Examples 1 to 20 (A-1) to 100 parts of EVOH (A-3),
A resin composition containing a composite compound (P) as shown in Table 1 or a resin composition containing a combination of the composite compound (P) and a higher fatty acid metal salt (Q) was pelletized using an extruder under the following conditions. The pellet production efficiency in this case was evaluated from two points: resin adhesion to the screw and pellet production amount, using the method described below.

○ Bunsho i fresh extruder 90mm diameter extrusion Iso extrusion rew L/D=26. Compression ratio 3.5 screen mesh, 60/120/60 mesh die Pellet die extrusion temperature
Cylinder tip 230℃
210℃Screw rotation speed
75rpa+ ○Evaluation method of production efficiency ゛・Resin adhesion to Suffix IJ, - After 8 hours of continuous extrusion molding and shaping, the extruder was disassembled and the amount of burned resin and lumps adhering to the screw surface was measured. was evaluated on a scale of 1 (not at all) to 5 (entirely adhered).

- Beret production amount Measure the production amount of berets per unit time (1 hour) (unit 2 to 4/br).

Furthermore, the following experiments were conducted.

The pellets obtained in each example were fed to an extruder under the following conditions to produce a film molded product (thickness: 30 μm). The quality of such films was evaluated by blocking resistance.

○Molding conditions Extruder 40mm diameter extrusion rock extrusion L/I)~28. Compression ratio 3.2g
B Fishtail die extrusion temperature
The tip of the cylinder is 230℃.
200℃Screw rotation speed 3Orpm ○ Film quality evaluation method ・Blocking resistance 20℃×95%RH1 and 20' (: X 80%R
Two of the above films are superimposed at H, and a load I is applied to this.
Measure the static friction coefficient when kg is applied.

Examples 1 to 12 of the above results are shown in Table 1, and Examples 13 to 12 are shown in Table 1.
20 are summarized in Table 2.

Control Example EVOH (A-1) to (A-3) used in the Example
) was pelletized and filmed in the same manner as in the same procedure except that the composite compound (P) was not added, and the production efficiency and film properties were evaluated in the same manner as above.

Reference Example For reference, polyethylene powder (density 0.96, M
Io, 8) was melted and pelletized under the same conditions as the pelletizing conditions in Example 1.

The production efficiency in this case was measured in the same manner as above.

The results of the control example and reference example are also shown in Table 2.

Claims (1)

[Claims] 1. A saponified ethylene-vinyl acetate copolymer having an ethylene content of 20 to 80 mol% and a degree of saponification of the vinyl acetate portion of 90 mol% or more with the general formula M_xAl_y(OH)_2_x_+_3_y_-_2
Composite compound represented by _z(E)_z・_aH_2O (in the formula, M is Mg, Ca or Zn, E is CO_3 or HPO_4, x, y, z are positive numbers, a is 0 or a positive number) (
A resin composition containing P). 2. The resin composition according to claim 1, wherein the compounding ratio of the composite compound (P) to the saponified ethylene-vinyl acetate copolymer is 0.005 to 5% by weight. 3. A saponified ethylene-vinyl acetate copolymer with an ethylene content of 20 to 80 mol% and a degree of saponification of the vinyl acetate portion of 90 mol% or more with the general formula M_xAl_y(OH)_2_x_+_3_y_-_2
Composite compound represented by _z(E)_z・_aH_2O (in the formula, M is Mg, Ca or Zn, E is CO_3 or HPO_4, x, y, z are positive numbers, a is 0 or a positive number) (
P) and a metal salt of a higher fatty acid having 10 to 22 carbon atoms (Q). 4. The resin composition according to claim 3, wherein the blending ratio of the composite compound (P) to the saponified ethylene-vinyl acetate copolymer is 0.005 to 5% by weight. 5. The blending ratio of the metal salt (Q) of the higher fatty acid to the saponified ethylene-vinyl acetate copolymer is 0.005 to 2.
The resin composition according to claim 3, which is % by weight. 6. The resin composition according to claim 3, wherein the metal salt of higher fatty acid (Q) is a metal salt of stearic acid.