JPH0618956B2 - Resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a saponified ethylene-vinyl acetate copolymer resin composition having remarkably improved production efficiency and quality.

[Prior Art] Saponified ethylene-vinyl acetate copolymer (hereinafter referred to as EVOH
Abbreviated as)) mechanical strength such as impact strength and tensile strength,
Solvent resistance, chemical resistance, gas barrier properties such as oxygen, aroma retention,
Since it is very excellent in oil resistance and also non-static property,
Various packaging materials including food products, multilayer laminated films,
It is widely used for containers, bottles, mechanical parts, engineering plastics for electric appliances, etc.

[Problems to be Solved by the Invention] However, EVOH is inferior in production efficiency during melt molding to other thermoplastic resins such as polyethylene and polypropylene, that is, the amount of resin discharged from a nozzle per unit time is small. There is a unique EVOH problem. That is, the theoretical discharge amount per revolution of the screw and the actual discharge amount are not always the same, 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. While the amount can be expected, only a discharge amount of about 50 to 60% of the theoretical value can be obtained in EVOH. Although the cause is not clear, it is an urgent need for the molder to more efficiently mold the EVOH.

The long run property of EVOH during melt molding, that is, the problem that continuous melt molding cannot be performed for a long period of time because the resin melt adheres to the inner wall of the extruder, can be improved by adding various additives from the past. Proposed (for example, Japanese Patent Publication No. 48-32074)
However, the improvement of the long-run property is not always directly connected to the increase of the discharge amount, and the discharge amount does not change so much even if the long-run property is improved by the conventional method.

Needless to say, if good numerical values are obtained for both the long-run property and the discharge amount, then better production efficiency can be achieved.

As one of such measures, the present applicant has previously proposed a method of blending a hydrotalcite compound (Japanese Patent Laid-Open No. 62-1524).
No. 6).

However, it was revealed that this method also has room for improvement in terms of increase in discharge amount and stability over time.

[Means for Solving Problems] However, as a result of various investigations by the present inventors in order to solve the above problems, an ethylene content of 20 to 80 mol% and a degree of saponification of a vinyl acetate portion of 90 were obtained. General formula for EVOH above mol% (However, ▲ M 2 ⁺ ₁ is at least one metal selected from Mg, Ca, Sr and Ba, ▲ M ²⁺ ₂ is Zn, Cd,
A metal selected from Pb and Sn, M ³⁺ is a trivalent metal, A
ⁿ⁻ is an n-valent anion, x, y ₁ , y ₂ , and m are 0 <
x ≦ 0.5, 0.5 <y ₁ <1, y ₁ + y ₂ = 1 and 0 ≦ m <2
The EVOH-based resin composition containing the hydrotalcite-based solid solution (P) represented by the formula (1) significantly improves the discharge amount and suppresses the fluctuation of the discharge amount over time. Further, when the solid solution (P) and the metal salt of a higher fatty acid having 10 to 22 carbon atoms (Q) are used in combination, the discharge rate is increased, the stability and the long-run property are improved, and the production is further improved. It has been found that efficiency can be achieved, and the present invention has been completed.

Moreover, when a molded product obtained from the resin composition of the present invention is formed into, for example, a film, it is possible to expect an extremely good quality in which blocking is unlikely to occur. This is also one that also has an industrially very important effect. is there.

The EVOH, solid solution (P), and higher fatty acid metal salt (Q) of the resin composition of the present invention will be described below.

First, EVOH used in the present invention has an ethylene content of 20 to 80 mol%, preferably 25 to 70 mol%,
The vinyl acetate moiety may have a saponification degree of 90 mol% or more, preferably 97 mol% or more. When the ethylene content is less than 20 mol%, the thermal stability is poor and the melt moldability is deteriorated. When the ethylene content is more than 80 mol%, not only the oxygen barrier property is deteriorated, but also its composition becomes close to polyethylene, and the discharge amount is Since the problem of decrease in the temperature hardly occurs, the need for the solid solution (P) is eliminated. When the degree of saponification of the vinyl acetate portion is less than 90 mol%, the thermal stability is poor and the physical properties such as oxygen barrier property, oil resistance and water resistance are deteriorated, so that it is not practical. The EVO in the present invention
H includes ethylene and vinyl acetate (or saponified vinyl alcohol), unsaturated carboxylic acid or its ester or salt, unsaturated sulfonic acid or its salt, (meth) acrylamide, (meth) acrylonitrile, propylene, A small amount of about 10 mol% or less of a third component such as an α-olefin such as butene, α-octene or α-octadecene, or a vinyl ester other than vinyl acetate may be contained.

The most significant feature of the present invention is that the EVOH has the general formula (However, ▲ M 2 ⁺ ₁ is at least one metal selected from Mg, Ca, Sr and Ba, ▲ M ²⁺ ₂ is Zn, Cd,
A metal selected from Pb and Sn, M ³⁺ is a trivalent metal, A
ⁿ⁻ is an n-valent anion, x, y ₁ , y ₂ , and m are 0 <
x ≦ 0.5, 0.5 <y ₁ <1, y ₁ + y ₂ = 1 and 0 ≦ m <2
It is to mix the hydrotalcite-based solid solution (P) represented by (a positive number).

In the above general formula, Mg and Ca are preferable as M ²⁺ . Further, as M ²⁺ , Zn and Cd are desirable. M
Examples of ³⁺ include Al, Bi, In, Sb, B, Ga, and Ti, but Al is practical.

Further, as A ⁿ⁻ , CO ₃ ²⁻ , OH ⁻ , HCO ₃ ⁻ ,
Salicylate ion, citrate ion, tartrate ion, N
O ₃ ⁻ , I ⁻ , [Fe _{(CN) 6] ^{4-, ClO 4 -, CH 3}} CO
O ⁻ , CO ₃ ²⁻ , And OH ⁻ are useful.

These may be surface-treated with higher fatty acids, anionic surfactants, lan coupling agents, titanate coupling agents, glycerin fatty acid esters, and the like.

Specific examples of (P) include [Mg _0.75 Zn _0.25 ] _0.67 Al
_0.33 (OH) ₂ (CO ₃ ) _0.165 · 0.45H ₂ O [Mg _0.79 Zn _0.21 ] _0.7 Al _0.3 (O
H) ₂ (CO ₃ ) _0.15 [Mg _6/7 Cd _1/7 ] _0.7 Al _0.3 (OH) ₂
(CH ₃ COO) _0.3 · 0.34H ₂ O [Mg _5/7 Pb _2/7 ] _0.7 Al _0.3 (OH) ₂
(CO ₃ ) _0.15 · 0.52H ₂ O [Mg _0.74 Zn _0.26 ] _0.68 Al
_0.32 (OH) ₂ (CO ₃ ) _0.16 [Mg _0.56 Zn _0.44 ] _0.68 Al
_0.32 (OH) ₂ (CO ₃ ) _0.16 · 0.2H ₂ O [Mg _0.81 Zn _0.19 ] _0.74 Al
_0.26 (OH) ₂ (CO ₃ ) _0.13 [Mg _0.75 Zn _0.25 ] _0.8 Al _0.2 (O
H) ₂ (CO ₃ ) _0.10 · 0.16H ₂ O [Mg _0.71 Zn _0.29 ] _0.7 Al _0.3 (O
H) ₂ (NO ₃ ) _0.30 [Mg _0.14 Ca _0.57 Zn _0.28 ] _0.7 Al
_0.3 (OH) _2.3 · 0.25H ₂ O and the like can be mentioned.

The amount of such solid solution (P) mixed with EVOH is 0.00
It is 5 to 5% by weight, and more preferably 0.08 to 3% by weight. If it is less than 0.005% by weight, the effect of the present application that the production efficiency is improved cannot be obtained, and if it exceeds 5% by weight, the effect cannot be expected for the amount, and it is not economical.

When the metal salt (Q) of higher fatty acid having 10 to 22 carbon atoms is used in combination with the solid solution (P), the discharge efficiency is increased, the long-run property is improved, and the production efficiency is further improved. .

Examples of such higher fatty acid (Q) include lauric acid, tridecylic acid, myristic acid, pentadecyl acid, palmitic acid,
Heptadecyl acid, stearic acid, nonadecanoic acid and the like can be mentioned, and as the metal salt, alkali metal salts such as sodium salt and potassium salt, magnesium salt, calcium salt,
Alkaline earth metal salts such as barium salts and also zinc metal salts are used. Among them, the metal salt of stearic acid is particularly remarkable in terms of the effect. The compounding amount of the metal salt (Q) with respect to EVOH is usually 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 is obtained, while if it exceeds 2% by weight, not only is it economically disadvantageous, but the production efficiency tends to decrease, which is not desirable.

The solid solution (P) or the higher solid fatty acid metal salt (Q) is added and mixed with the EVOH powder or pellets by a Henschel mixer, a tumbler or the like. Thereafter, a suitable means such as supplying the blended product to an extruder and subjecting it to the desired molding as it is, or pelletizing it once and subjecting it to the desired molding is employed.

The temperature condition for melt molding is about 160 to 260
It is desirable to set the temperature to ° C. Known additives such as glass fiber, carbon fiber and other reinforcing materials, low molecular weight polyethylene, low molecular weight polypropylene, paraffin, amide type, epoxy type lubricants, fillers, colorants, stabilizers, foaming agents, etc. The agent may be blended appropriately.
Also, a thermoplastic resin for modification may be blended in an appropriate amount within the range that does not impair the excellent properties of EVOH during melt molding.

As such thermoplastic resin, high density, medium density, low density various polyethylene, polypropylene, polybutene, homopolymers such as polypentene, ethylene-propylene copolymer, 1-butene mainly ethylene or propylene,
Copolymers with α-olefins having about 2 to 20 carbon atoms such as 1-hexene, and olefin-vinyl acetate copolymers having a composition relatively close to that of olefin such as ethylene or propylene of 90 mol% or more. Polymers, various polyolefin resins such as olefin- (meth) acrylic acid ester copolymers, or graft-modified polyolefins obtained by graft-modifying these with unsaturated carboxyl groups, polyamide-based resins such as nylon-6 and nylon-6,6 Resin, vinyl chloride resin, vinylidene chloride resin, acrylic resin, acrylamide resin, styrene resin, vinyl ester resin, polyester resin and polyester elastomer, polyurethane elastomer, polycarbonate, polyacetal, chlorinated polyethylene resin, chlorine Conversion Is any such polypropylene-based resin.

As the melt molding method, any molding method such as an injection molding method, a compression molding method, and an extrusion molding method can be adopted. Among these, examples of the extrusion molding method include a T-die method, a hollow molding method, a pipe extrusion method, a filament extrusion method, a profile die extrusion method, and an inflation method. The shape of the molded product is arbitrary, and not only pellets but also films, sheets, tapes, bottles, pipes, filaments, modified cross-section extrudates and the like, and multilayer laminates of these and other resins are also important.

As a partner resin when laminating, low density polyethylene, medium density polyethylene, high density polyethylene, ethylene-vinyl acetate copolymer, ionomer, ethylene-α
-Olefin (C3-C20 α-olefin) copolymer, ethylene-acrylic acid ester copolymer, polypropylene, propylene-α-olefin (C2-C2)
0-α-olefin) copolymers, homo- or copolymers of olefins such as polybutene and polypentene, or those obtained by graft-modifying homo- or copolymers of these olefins with unsaturated carboxylic acids or their esters. Polyolefin resin, polyester resin, polyamide resin, copolyamide resin, vinyl chloride resin, vinylidene chloride resin, acrylic resin, acrylamide resin, vinyl ester resin, polyester resin and polyester elastomer, polyurethane elastomer , Polycarbonate, polyacetal, chlorinated polyethylene resin, chlorinated polypropylene resin and the like. Coextrusion of different saponified ethylene-vinyl acetate copolymers is also possible.

The layer structure is the EVOH resin composition layer of the present application is A (A ₁ ,
A ₂ , ..., And the thermoplastic resin layer is B (B ₁ , B ₂ , ...).
…), When the adhesive layer provided as necessary is C,
If it is a film, a sheet, or a bottle, not only a two-layer structure of A / B but also A / B / A, B / A / B, B ₁ / B ₂ /
A, B / A ₁ / A ₂ , A / B / A / B / A, A ₂ / A ₁
/ B / A ₁ / A ₂ , A / C / B, A / C / B / C / A,
B / C / A / C / B, A / C / B / C / A / C / B / C
/ A can be configured arbitrarily, and if it is a filament, A and B are bimetal type, core (A) -sheath (B) type, core (B) -sheath
Any combination such as type (A) or eccentric core-sheath type is possible. Further, either or both of the above A and B may be blended with the other resin, or a resin that improves the adhesiveness of both resins may be blended.

Molded products after melt molding, co-extrusion molded products, melt-coated molded products are heat-treated, cooled, rolled, uniaxially or biaxially stretched, printed, dry laminated, solution or melt-coated, bag-made as required. Processing, deep drawing, box processing,
Tube processing, split processing, etc. can be performed.

[Effect] Thus, by using the resin composition of the present invention, not only is the discharge amount at the time of molding remarkably improved, which contributes to the improvement of production efficiency, but also foreign matter (carbonized resin) in the melt. The resulting molded product is blocking, fish,
The number of eyes can be small and the quality can be stable and good. Such an effect greatly affects the quality of a molded product having a multilayer structure using the resin composition of the present invention, and therefore its usefulness is extremely large.

[Function] The resin composition of the present invention is useful mainly for molded products such as various packaging films including food packaging, containers, bottles, food trays, sheets, and various equipment parts. Of course, it can be used for various purposes such as extrusion coating of plastics.

EXAMPLES Next, the composition of the present invention will be further described with reference to examples. Hereinafter, “part” is expressed on a weight basis unless otherwise specified.

EVOH (A-1) used: ethylene content 31 mol%, saponification degree of vinyl acetate component 99.1 mol%, melt index (MI) 4.0 (A-2) at 210 ° C. (the same conditions apply below): Ethylene content 25 mol%, saponification degree of vinyl acetate component 99.2 mol%, MI 3.6 (A-3): ethylene content 55 mol%, saponification degree of vinyl acetate component 98.3 mol%, MI 25 Examples 1 to 20 (A-1) to (A-3) 100 parts of EVOH,
A resin composition containing the solid solution (P) as shown in Table 1 or a resin composition containing the solid solution (P) and a metal salt of a higher fatty acid (Q) in combination was pelletized by an extruder under the following conditions. By the method described below the production efficiency of pellets at such time,
Evaluation was made from two points: resin adhesion to the screw and pellet production amount.

○ Molding conditions Extruder 90mm diameter extruder Screw L / D = 26, compression ratio 3.5 Screen mesh 60/120/60 mesh Die Pellet die Extrusion temperature Sirilender tip 230 ℃ Die 210 ℃ Screw rotation speed 75rpm ○ Production efficiency Evaluation method-Adhesion of resin to screw After performing extrusion molding continuously for 8 hours, disassemble the extruder,
The amount of burnt / kogation of the resin adhering to the screw surface was evaluated on a scale of 1 (none) to 5 (overall adhesion).

・ Pellet production volume Pellet production volume per unit time (1 hour) (Unit:
kg / hr) is measured after 1 hour and 10 hours.

Further, the following experiment was 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 40 mm diameter extruder Screw L / D = 28, compression ratio 3.2 Die fish tail die Extrusion temperature Silender tip 230 ° C Die 200 ° C Screw rotation speed 30 rpm ○ Film quality evaluation method ・ Blocking resistance The static friction coefficient was measured when two films were superposed at 20 ° C. × 95% RH and 20 ° C. × 80% RH and a load of 1 kg was applied to them.

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

Control Example EVOH (A-1) to (A-) used in Examples
Pelletization and film formation were performed according to the same example except that the solid solution (P) was not added to 3), and the production efficiency and film physical properties were evaluated by the same means as above.

Reference example Polyethylene powder (density 0.96, MI
0.8) was melted and pelletized under the same pelletization conditions as in Example 1.

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

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

Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display area C08K 3:24 5:09 (56) References JP 62-15243 (JP, A) JP 62 -11748 (JP, A) JP 60-238345 (JP, A) JP 60-199040 (JP, A) JP 64-69652 (JP, A)

Claims (6)

[Claims] 1. A saponified product of an ethylene-vinyl acetate copolymer having an ethylene content of 20 to 80 mol% and a saponification degree of a vinyl acetate portion of 90 mol% or more, having a general formula. (However, ▲ M 2 ⁺ ₁ is at least one metal selected from Mg, Ca, Sr and Ba, ▲ M ²⁺ ₂ is Zn, Cd,
A metal selected from Pb and Sn, M ³⁺ is a trivalent metal, A
ⁿ⁻ is an n-valent anion, x, y ₁ , y ₂ , and m are 0 <
x ≦ 0.5, 0.5 <y ₁ <1, y ₁ + y ₂ = 1 and 0 ≦ m <2
A resin composition containing a hydrotalcite-based solid solution (P) represented by 2. The compounding ratio of the solid solution (P) to the saponified ethylene-vinyl acetate copolymer is 0.005 to 5% by weight.
The resin composition according to claim 1, which is 3. A saponified product of an ethylene-vinyl acetate copolymer having an ethylene content of 20 to 80 mol% and a saponification degree of a vinyl acetate portion of 90 mol% or more, having a general formula. (However, ▲ M 2 ⁺ ₁ is at least one metal selected from Mg, Ca, Sr and Ba, ▲ M ²⁺ ₂ is Zn, Cd,
A metal selected from Pb and Sn, M ³⁺ is a trivalent metal, A
ⁿ⁻ is an n-valent anion, x, y ₁ , y ₂ , and m are 0 <
x ≦ 0.5, 0.5 <y ₁ <1, y ₁ + y ₂ = 1 and 0 ≦ m <2
A solid number (P) and a metal salt of a higher fatty acid having 10 to 22 carbon atoms (Q)
A resin composition comprising: 4. The compounding ratio of the solid solution (P) to the saponified ethylene-vinyl acetate copolymer is 0.005 to 5% by weight.
The resin composition according to claim 3, which is 5. The compounding ratio of the metal salt (Q) of the higher fatty acid to the saponified ethylene-vinyl acetate copolymer is 0.00.
The resin composition according to claim 3, which is 5 to 2% by weight. 6. The resin composition according to claim 3, wherein the metal salt (Q) of higher fatty acid is a metal salt of stearic acid.