JP2521806B2 - Ionomer composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to an ethylene copolymer ionomer (hereinafter sometimes simply referred to as ionomer) composition having excellent heat resistance, impact resilience, impact resistance, processability, and the like. Regarding things.

[Prior Art] Ionomer has excellent heat-sealing property, heat-bonding property, low odor property, hygiene property, transparency, luster, oil resistance, impact resistance, impact resilience, abrasion resistance, packaging film, and adhesive property. Film, automobile interior materials, automobile exterior materials, golf ball skins,
It is used in a wide range of applications as molded articles such as tools and foamed articles such as shoe soles of sports shoes.

In addition to being used as a single composition, the ionomer is used as a laminate with a resin film having a gas barrier property, or added to polyamide, polyester, etc. as an impact resistance improver. It is often used as a molded product of a blend.

Generally, in these applications, an ionomer is a general molding method for a thermoplastic resin, such as extrusion molding, injection molding, or compression molding. Molded. This is because the ionomer has a crosslink which is a metal ion bond in its structure, but the metal ion bond is easily melted at a high temperature and exhibits excellent fluidity.

[Problems to be Solved by the Invention] However, since the ionomer has a low melting point, its mechanical strength is extremely lowered in a temperature range above the melting point. Therefore, there is a drawback that problems such as deformation often occur when the ionomer molded product is post-processed at a high temperature or when the molded product is exposed to a high temperature during use. For example, when used as a packaging film for retort foods, the film may be deformed or destroyed by heat during retort treatment, and in a normal packaging film, a sealing portion may be fused during heat sealing. In the application of the adhesive film, there is a problem that the adhesive portion is displaced when exposed to high temperature. Furthermore, interior materials for automobiles,
In applications such as exterior materials, there is a problem that an ionomer molded product is deformed when exposed to high temperature due to heat from an engine, direct sunlight, or the like. Therefore, ionomers, while having the excellent characteristics as described above, are severely restricted in their applications.

Furthermore, since the ionomer has too good fluidity in the high temperature region as described above, the parison hangs down by its own weight in the hollow molding, which is a drawback that the molding is very difficult. In addition, in the field of hollow containers, lack of rigidity has been a problem.

Therefore, high-density polyethylene (hereinafter abbreviated as HDPE) and polypropylene (hereinafter abbreviated as PP) are mainly used for such hollow molding applications. However, since both have poor wear resistance, the surface of the product is easily scratched, and
In the case of a bag or the like, when the corners are dented, the impact resilience is small, and there is a problem that it is difficult to return to the original shape.

Therefore, for use in these applications, a method of improving heat distortion resistance and improving melt fluidity at high temperature while maintaining excellent properties such as oil resistance, abrasion resistance, and impact resistance of ionomer is desired. However, the applicant of the present invention has previously proposed a composition obtained by reacting an ionomer with an olefin-based copolymer having an epoxy group in the side chain (Japanese Patent Application No. 63-193454). issue). According to the studies by the present inventors, it has been found that such a composition has improved properties such as hollow moldability as compared with the ionomer. And while making use of these improved properties, this composition is not only a hollow molded container if various rigid ones, especially those with high rigidity are obtained,
It was also found that further expansion of applications can be expected in various fields of use such as automobile exterior parts such as bumper guards and air dams.

Therefore, an object of the present invention is to provide an ionomer composition having low fluidity at high temperature and various rigidity while utilizing the excellent properties such as oil resistance, impact resistance, abrasion resistance, and impact resilience of the ionomer. To do.

[Means for Solving the Problems] The present invention relates to an ethylene copolymer ionomer (A) 90 to 99.5% by weight containing ethylene and an unsaturated carboxylic acid salt as essential polymer constituents, an α-olefin, and glycidyl. The ethylene polymer (C) is blended in a proportion of 5 to 150 parts by weight with respect to 100 parts by weight of a component comprising 0.5 to 10% by weight of a copolymer (B) with (meth) acrylate or glycidyl ether. Is an ionomer composition.

The ethylene copolymer ionomer (A) used in the present invention contains ethylene and an unsaturated carboxylic acid salt as essential polymer constituent components, and also contains an unsaturated carboxylic acid and an unsaturated carboxylic acid as optional components. Acid ester,
Other unsaturated compounds may be contained as a polymerization component. Such ionomers generally neutralize at least a portion of the unsaturated carboxylic acid component of a copolymer of ethylene and an unsaturated carboxylic acid and optionally other unsaturated compounds with metal ions and / or organic amines. Alternatively, it can be obtained by saponifying at least a part of the unsaturated carboxylic acid ester component of the copolymer consisting of ethylene and the unsaturated carboxylic acid ester and, optionally, other unsaturated compound.

In the copolymer containing ethylene as an ionomer raw material, unsaturated carboxylic acid, and other unsaturated compound as an optional component, the unsaturated carboxylic acid preferably has about 3 to 8 carbon atoms, specifically acrylic acid. , Methacrylic acid, fumaric acid, itaconic acid, maleic anhydride, maleic acid monomethyl ester, maleic acid monoethyl ester and the like are used. Among these, acrylic acid, methacrylic acid, maleic anhydride and the like are preferably used.
Such unsaturated carboxylic acid may be random copolymerized or graft copolymerized, but from the viewpoint of transparency, random copolymerized one is preferable. Further, as an optional component of the copolymer, the other unsaturated compound as the third component may be an ester of unsaturated carboxylic acid, an alkenyl ester of saturated carboxylic acid, and the like, and more specifically, methyl acrylate, acrylic Ethyl acrylate, isobutyl acrylate, n-butyl acrylate,
2-ethylhexyl acrylate, methyl methacrylate,
Vinyl acetate etc. can be illustrated.

As these ethylene-unsaturated carboxylic acid copolymers, the ethylene content is 40 to 99 wt%, preferably 50 to 98
%, And the unsaturated carboxylic acid is preferably present in an amount of 1 to 50% by weight, preferably 2 to 40% by weight.
When the ethylene-unsaturated carboxylic acid copolymer contains a third component, it is desirable that the third component be present in an amount up to 50% by weight, preferably up to 40% by weight.

The ethylene - as a neutralizing component in the unsaturated carboxylic acid ^{copolymer, Na +, K +, Li} +, Ca ++, Mg ++, Zn -, Cu -, Co
⁺⁺ , Ni ⁺⁺ , Mn ⁺⁺ , Al ^{+++ and} other monovalent to trivalent metal cations, and / or n-hexylamine, hexamethylenediamine, 1.3-bisaminomethylcyclohexane,
Examples thereof include organic amines such as meta-xylene diamine. The carboxyl salt produced by the neutralization acts as a catalyst for the binding reaction between the carboxyl group of the ionomer and the epoxy group of the olefin copolymer. Although the reaction occurs even if there is no neutralizing component, the crosslinking tends to occur unevenly, and the degree of improvement in mechanical strength at high temperatures is small. The neutralizing component can be used alone or in combination of two or more components.

A suitable ionomer is based on a copolymer of ethylene and an unsaturated carboxylic acid synthesized by a high pressure radical polymerization method, or a third component optionally used,
This is an ionomer in which some or all of the acidic groups are neutralized with cations. The degree of neutralization is usually 5 to 100%, preferably 1.
0 to 90% is used. The melting point of such an ionomer is generally about 70 to 105 ° C. Regarding the flow characteristics, it is preferable to use a melt flow rate (MFR) measured at 190 ° C. under a load of 2160 g of 0.01 to 1000 dg / min, particularly 0.1 to 200 dg / min.

The olefin-based copolymer (B) blended with the ionomer (A) in the present invention is a copolymer of α-olefin and glycidyl acrylate or glycidyl methacrylate (hereinafter referred to as glycidyl (meth) acrylate) or glycidyl ether. is there. (Hereinafter, a copolymer of the above α-olefin and glycidyl (meth) acrylate or glycidyl ether may be referred to as an “α-olefin / glycidyl compound copolymer”.) The α-olefin has 2 carbon atoms. -8 alpha-olefins are preferred. Examples are ethylene, propylene, butene-1.
Etc.

Examples of glycidyl (meth) acrylate and glycidyl ether include glycidyl methacrylate, glycidyl acrylate, vinyl glycidyl ether, allyl glycidyl ether, and 2-methylallyl glycidyl ether.

The monomer that constitutes the α-olefin / glycidyl compound copolymer does not have to be two components. In addition to the olefin and epoxy group-containing monomer, a third component such as unsaturated carboxylic acid ester or vinyl ester may be contained as a monomer component. These may be, for example, those exemplified above as the third component of the copolymer which is a raw material of the ionomer. When the third component is contained, there is an effect that the crosslinked ionomer has excellent transparency. Examples of these copolymers include those having an olefin content of 40 to 99.
% By weight, preferably 50-98% by weight, glycidyl (meth)
Acrylate or glycidyl ether is 0.5 to 20% by weight, preferably 1 to 15% by weight, and a third component such as unsaturated carboxylic acid ester or vinyl ester is 0 to 49.5% by weight, preferably 0 to 40% by weight. It is preferably used. If the content of the glycidyl compound is too small, the effect of reducing the fluidity of the ionomer at high temperature due to crosslinking is small, and if the content is too large, crosslinking tends to become non-uniform, so an appropriate content is obtained. It is desirable to adjust.

As the α-olefin / glycidyl compound copolymer, any of a random copolymer, a block copolymer and a graft copolymer can be used, but the random copolymer is preferable from the viewpoint of uniformity of crosslinking. The olefin copolymer can be obtained by radical polymerization under a pressure of 500 to 3000 kg / cm ² and a temperature of 150 to 280 ° C.

When an ethylene-based copolymer is used as the copolymer, it is preferable to select one having a melt flow rate of 0.01 to 1000 dg / min, particularly 0.1 to 200 dg / min measured at 190 ° C. under a load of 2160 g. .

The reaction mechanism between the ionomer component (A) and the α-olefin / glycidyl compound copolymer (B) in the present invention is as follows: the carboxyl group of the ionomer component reacts with the epoxy group of the side chain of the olefin copolymer. It is considered that a crosslinked product is formed in which the chains are covalently bonded via the α-olefin / glycidyl compound copolymer. At that time, it is considered that the carboxylate in the ionomer acts as a catalyst for the reaction. By-products such as water and gas are not produced by the reaction, and therefore foaming due to by-products is not involved.

Both reactions can be easily performed by melt-kneading. Melt kneading is performed by screw extruder, roll mixer,
It is carried out under a temperature condition of 100 to 300 ° C., preferably 150 to 280 ° C. in a melt mixing or processing device for thermoplastic resin such as Banbury mixer.

The blending ratio of both varies depending on the content of the functional group involved in the reaction and the desired physical properties of the intended reaction product,
When the total of both is 100% by weight, the ionomer is 9
0-99.5% by weight, preferably 95-99% by weight, α-
The olefin / glycidyl compound copolymer is 0.5 to 10% by weight, preferably 1 to 5% by weight.

If the amount of the α-olefin / glycidyl compound copolymer used is less than 0.5% by weight, the effect of lowering the fluidity at high temperature is not substantially obtained, and if it exceeds 10% by weight, the temperature is high. Flowability becomes too low and moldability is significantly impaired.

The ethylene-based polymer (C) used in the present invention means (1) ethylene and propylene, butene-1, pentene-1, 4-methylpentene-1, octene-1 or a mixture thereof as an ionic polymerization catalyst. Of 0.89 to 0.93 g / c, obtained by polymerizing in liquid or gas phase in the presence of
m ³ and preferably 0.90 to 93 g / cm ³ linear low density polyethylene.

(2) A linear medium-high-density polyethylene having a density of 0.93 g / cm ³ or more obtained by polymerizing ethylene in a liquid phase or a gas phase in the presence of an ionic polymerization catalyst. In this case, in order to improve the impact resistance, a small amount of α-olefin such as propylene and butene may be copolymerized.

(3) Branched low-density polyethylene obtained by bulk polymerization of ethylene under high pressure in the presence of a radical polymerization catalyst.
In this case, a small amount of a vinyl ester such as vinyl acetate or an unsaturated carboxylic acid alkyl ester such as acrylic acid ethyl ester may be copolymerized in order to improve impact resistance.

And so on.

In particular, (1) and (2) are suitable for obtaining high rigidity. When the branched low-density polyethylene of (3) is blended, a low-rigidity product and a high-rigidity product can be obtained by appropriately selecting the copolymerization component and its amount.

The blending ratio of the component comprising the ionomer (A) and the α-olefin / glycidyl compound copolymer (B) and the ethylene copolymer (C) is 5 to 1 with respect to 100 parts by weight of the former.
The amount is 50 parts by weight, preferably 20 to 100 parts by weight. When the blending ratio of the ethylene polymer (C) is less than the above range, the modifying effect is small, and when the blending ratio is more than the above range, excellent properties of the ionomer are impaired, which is not desirable.

As the ethylene polymer (C), its MFR (190 ° C,
2160g under load) 0.01-70g / 10min, preferably 0.03-3
It is preferably 0 g / 10 minutes, when it is less than this, the moldability is deteriorated because the fluidity is lowered, and when it is more than this, the reaction between the ionomer and the α-olefin / glycidyl compound copolymer is caused. The compatibility with the product decreases.

When the ethylene-based copolymer (C) is blended, the reaction products of (A) and (B) can be blended using an ordinary mixing device such as a screw extruder, a roll mixer, or a Banbury mixer. However, the ethylene-based polymer does not hinder the reaction between (A) and (B).
Prior to the reaction of (A) and (B), either or both of (A) and (B) may be blended, or during the reaction of (A) and (B), it is supplied to the reactor. You may.

EXAMPLES Next, the present invention will be described with reference to examples.

The abbreviations for the ethylene polymers used in the examples have the following meanings.

L-LDPE Linear low-density polyethylene HDPE Linear high-density polyethylene LDPE Branched low-density polyethylene Furthermore, in the present example, the ionomer composition produced and the test method for the molded product thereof are as follows.

Test method MFR (melt flowability), JIS K-6710, load 216
The measurement was performed at 0 g and a measurement temperature of 190 ° C.

Tensile strength (stress at break, elongation), JIS K −7113−1977
In accordance with the above, a JIS 2 type test piece having a thickness of 2 mm was measured at a tensile speed of 200 mm / min.

Bending rigidity and a test piece having a thickness of 2 mm were measured based on ASTM D-747.

Hollow Moldability The hollow moldability was evaluated under the following conditions, and those that could be molded without problems were rated as ◯, those that could not be molded were rated as ×, and those that could be molded but had problems were rated as Δ.

Molding machine Multi-layer hollow molding machine manufactured by Japan Steel Works, Ltd. Single layer molding using only 50mmφ extruders (30mmφ, 40mmφ, 50mmφ, 3 extruders) Molded product dimensions 300ml hollow bottle, 0.7mm thickness Impact resilience Internal volume created by the hollow molding method described above
A 300 ml hollow bottle was dented with a finger, and those that immediately returned were marked with ◯, those that were difficult to return with were marked with x, and the middle was marked with Δ.

Impact strength A test piece with a thickness of 3 mm was left in a thermostatic chamber at -30 ° C for 3 hours, and then a harpoon-shaped tip from a height of 1.8 m.
A load of 3 kg was dropped spontaneously, and those that cracked were rated as ×, those that did not crack were rated as ○, and those that cracked were rated as Δ.

Example 1 Ionomer 1 (ethylene-methacrylic acid copolymer, ethylene content 96 mol%, methacrylic acid content 2.7 mol%, zinc methacrylate content 1.3 mol%) 9.8 kg in the amount shown in Table 1
And as an α-olefin / glycidyl compound copolymer,
Ethylene-vinyl acetate-glycidyl methacrylate copolymer (vinyl acetate content 5% by weight, glycidyl methacrylate content 8% by weight, MFR 6 g / 10 min .... abbreviated as EVAGMA hereinafter)
After adding 0.2 kg to a 150 l Henschel mixer, further HDP
E (Hi-Zex 5300B, MFR manufactured by Mitsui Petrochemical Industry Co., Ltd.)
0.4 g / 10 minutes, density 0.952 g / cm ³ , and 4 kg were added, and pre-kneading was performed for 5 minutes in an atmosphere of 23 ° C.

This kneaded material was mixed with a single screw of L / D = 28 for 40 m
Using an mφ extruder, the mixture was melt-kneaded and pelletized under the conditions of a die temperature of 200 ° C. and a screw rotation speed of 30 rpm. The pellets were evaluated for MFR and hollow moldability. In addition, a plate having a predetermined thickness was formed by hot press molding, and the tensile strength, flexural rigidity and impact strength were evaluated. Table 1 shows these results.

Example 2 Evaluation was made in the same manner as in Example 1 except that the amount of HDPE added was changed to 12 kg. The results are shown in Table-1.

Example 3 Evaluation was performed in the same manner as in Example 1 except that the amount of HDPE added was changed to 1 kg. The results are shown in Table-1.

Comparative Example 1 Evaluation was performed in the same manner as in Example 1 except that the amount of HDPE added was changed to 20 kg. The results are shown in Table-1.

Example 4 In Example 1, LLDPE (Ultzex 3010F manufactured by Mitsui Petrochemical Industry Co., Ltd., MFR.1.3g / 10) was used instead of HDPE.
Min, density 0.930 g / cm ³ ) was used, and evaluation was performed in the same manner as in Example 1. The results are shown in Table-1.

Example 5 In Example 1, instead of HDPE, LDPE (Mitsui Petrochemical Industrial Co., Ltd. Mirason E844, MFR.0.23g / 10 minutes, density
Evaluation was performed in exactly the same manner as in Example 1 except that 0.922 g / cm ³ ,) was used. The results are shown in Table-1.

Examples 6 and 7 Comparative Examples 2 and 3 Evaluations were made in the same manner as in Example 1 except that the compounding ratio in Example 1 was changed to the compounding ratio shown in Table 1.
Table 1 shows these results.

[Effect of the Invention] According to the present invention, the heat resistance is improved by adding the ethylene polymer (C) to the component composed of the ionomer (A) and the α-olefin / glycidyl compound copolymer (B). It is possible to obtain a composition which is excellent in impact resilience, impact resistance, workability, wear resistance and the like and has various rigidity, particularly high rigidity. Such a composition can be molded into a molded article having excellent physical properties by various molding methods such as injection molding, extrusion molding, vacuum molding, as well as hollow molding.

Claims (2)

(57) [Claims] 1. An ethylene copolymer ionomer (A) 90 to 99.5% by weight containing ethylene and an unsaturated carboxylic acid salt as essential polymer constituents, an α-olefin, and glycidyl (meth) acrylate or glycidyl ether. An ionomer composition obtained by blending the ethylene polymer (C) in an amount of 5 to 150 parts by weight with respect to 100 parts by weight of a component composed of 0.5 to 10% by weight of the copolymer (B). 2. The ionomer composition according to claim 1, wherein the ethylene copolymer ionomer (A), the copolymer (B) and the ethylene polymer (C) are melt-mixed in any order.