JP2521805B2 - Ionomer composition and method for producing crosslinked ionomer using the same - Google Patents

Description

TECHNICAL FIELD The present invention relates to a composition for producing a crosslinked ionomer and a method for producing a crosslinked ionomer using the same.

More specifically, it relates to a composition for producing a crosslinked ionomer obtained by mixing an ionomer and an ethylene / glycidyl compound copolymer, and a method for producing the crosslinked ionomer using the composition.

[Prior Art] An ionomer in which a part or all of the carboxyl groups of an ethylene-unsaturated carboxylic acid copolymer is neutralized with a metal cation and / or an organic amine compound has heat-sealability,
Utilizing the properties of excellent heat adhesion, low odor, hygiene, transparency, oil resistance, impact resistance, and abrasion resistance, packaging films, adhesive films, automobile interior materials, exterior materials, golf balls It is used in a wide range of applications as molded products such as skins and tools, and foamed molded products such as shoe soles of sports shoes.

Further, the ionomer is used not only as a single composition but also as a laminate with a resin film having a gas barrier property, or is added as an impact resistance improver to polyamide, polyester, etc. It is often used as a molded body.

In general, in these applications, the ionomer is molded into the above-mentioned molded product in a molten state by a molding method such as extrusion molding, injection molding or compression molding which is a general molding method for thermoplastic resins. Since the ionomer has a relatively low melting point, one of its advantages is that it can be molded at a low temperature.

[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 melted 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. Further, in applications such as automobile interior materials and exterior materials, there is a problem that the molded product of the ionomer is deformed when exposed to high temperature due to heat from the engine, direct sunlight, or the like. Therefore, ionomers, while having the excellent characteristics as described above, are severely restricted in their applications.

Therefore, it has been strongly desired to improve the mechanical strength at high temperature while maintaining the excellent characteristics of the ionomer described above. Conventionally, as a method of improving the mechanical strength at high temperature of a thermoplastic resin having a relatively low melting point, a low melting point thermoplastic resin and a high melting point thermoplastic resin are blended, or the low melting point resin is molded. A method of improving the mechanical strength of a low melting point resin at high temperature by cross-linking with an organic peroxide or an electron beam during or after molding is known.

However, in the method of blending an ionomer with a thermoplastic resin having a high melting point such as nylon or polyester, it is necessary that the thermoplastic resin having a high melting point does not exist in a proportion of 30% or more in the blended resin composition. However, there is a problem that it is difficult to improve the mechanical strength of this resin composition at high temperatures, but if a high melting point thermoplastic resin is blended with an ionomer at such a high ratio, the ionomer has The advantages of low temperature processability, transparency and thermal adhesion are lost.

On the other hand, a method of crosslinking a resin is known as a method of maintaining the mechanical strength at a high temperature while maintaining the characteristics of the low melting point resin such as processability at low temperature, transparency, and thermal adhesiveness. As a method of cross-linking, a method of adding an organic peroxide or the like to the resin to cross-link, and a method of irradiating the resin with an energy ray source such as an electron beam to cross-link are generally known. However, when the ionomer is cross-linked with an organic peroxide, the presence of an alkaline cation causes the peroxide to be easily decomposed, and the ratio of effectively acting on the cross-linking reaction decreases. Therefore, unless a considerably large amount of organic peroxide is used, sufficient crosslinking does not occur, and the crosslinked product causes foaming, coloring, and odor of the crosslinked product due to the gas of the decomposition by-product of the peroxide. In addition, the cross-linking is non-uniform, a phenomenon such as partial gel formation occurs, and the appearance of the molded product is likely to be damaged. Therefore, this cross-linking method cannot be applied to ionomers except for special applications such as foam moldings. Further, the crosslinking of an ionomer with an energy ray source such as an electron beam is an excellent crosslinking method in that there is no foaming or coloring associated with the crosslinking, but it extends only to the surface of the resin irradiated with the crosslinking and a layer close to the surface. Therefore, although it is applied to the cross-linking of a thin, flat shaped article such as a sheet or a film, it is not suitable for the cross-linking of a shaped article having a large wall thickness and a complicated shape, and the application range is significantly limited. Further, this crosslinking device has a drawback that it is economically inferior because it requires an expensive and special device such as an energy source irradiation device.

As a cross-linking method of an ionomer having no problems such as foaming, coloring, odor and the like, such as cross-linking by an organic peroxide, and also having an economical efficiency, the present inventors have proposed that an ionomer of an epoxy resin with a specific epoxy equivalent amount of A crosslinking method was disclosed (Japanese Patent Application No. 63-76169). This method also has an excellent advantage of not impairing the transparency of the ionomer, but since the ionomer and the epoxy resin have a large difference in softening temperature and melt viscosity, the ionomer in a continuous processing device such as a screw extruder. When epoxy resin is added, mixed and cross-linked, troubles such as screw slips are likely to occur. Further, when the ionomer is crosslinked with an extruder using a liquid epoxy resin at room temperature, a pump is required to inject the epoxy resin into the extruder at a high pressure. Therefore, this method has a drawback that the operation for crosslinking is not easy.

Further, as a soft resin for addition for improving the impact resistance of the thermoplastic resin, it has one or more epoxy groups in one molecule,
Resin with flexural modulus at room temperature of 10,000 Kg / cm ² or less 5
It is disclosed that a resin composition obtained by melt-mixing 95 parts by weight and 95 to 5 parts by weight of an ionomer resin neutralized with an alkali metal salt is used (JP-A-63-165448). However, in this composition, it is essential that at least 5 parts by weight of a resin having one or more epoxy groups in one molecule be blended with 95 parts by weight of an ionomer. When added in a large amount, gelation increases, processability deteriorates, the characteristics of the ionomer cannot be utilized, and it is not an effective method for modifying the ionomer resin.

As described above, the heat-sealing property of the ionomer, low odor, transparency, thermal adhesiveness, and other properties are maintained, and the purpose is to improve the mechanical strength at high temperature, and it is economical and There has been a demand for a cross-linking method that is easy to operate and a molded product thereof.

[Means for Solving the Problem] Therefore, the present inventors have not shown the above-mentioned problems of the conventional ionomer cross-linking method, require no special equipment, and are easy in the cross-linking operation and economical. As a result of diligent research on a crosslinking method of an excellent ionomer, an ionomer and a specific ethylene / glycidyl compound copolymer are blended at a specific ratio, and a method of crosslinking the ionomer with the ethylene / glycidyl compound copolymer is used. It was found that this problem can be effectively solved.

That is, the object of the present invention is to solve the conventional problems in industrial practice, the ethylene ionomer has, heat sealability, heat adhesion, low odor, transparency, oil resistance. An object of the present invention is to provide an economical method for producing an ionomer having mechanical strength at high temperature while maintaining excellent properties such as impact resistance and low-temperature processability, and a molded product of the ionomer.

The present invention comprises an ethylene-unsaturated carboxylic acid copolymer having an unsaturated carboxylic acid content of 2 to 40% by weight, at least a part of which is neutralized with a metal cation and / or an organic amine. Melt flow rate (190 ℃, 2
160g load) 0.1-200dg / min ionomer 100 parts by weight, glycidyl (meth) acrylate or glycidyl ether content of 0.5-20% by weight melt flow rate 0.1-200dg / min ethylene and glycidyl (meta). )
Copolymer with acrylate or glycidyl ether 0.3
The present invention relates to a composition for producing a crosslinked ionomer by a reaction under melting conditions, which is prepared by mixing ˜4.5 parts by weight, and a method for producing a crosslinked ionomer, which comprises reacting the composition under melt-kneading.

According to the present invention, an ionomer can be easily crosslinked by a usual thermoplastic resin processing or molding apparatus without requiring an expensive apparatus or a special apparatus, and the crosslinked ionomer of the present invention can be molded. The body has the heat sealability, heat adhesiveness, low odor, transparency, and oil resistance of the ionomer,
It possesses mechanical strength at high temperatures while retaining its excellent impact resistance.

Hereinafter, a method for crosslinking an ionomer with an ethylene / glycidyl compound copolymer and a raw material composition thereof according to the present invention will be specifically described.

At least part of the carboxyl groups of the ethylene and unsaturated carboxylic acid copolymer is neutralized with a metal cation and / or an organic amine. As the unsaturated carboxylic acid, an unsaturated carboxylic acid having 3 to 8 carbon atoms, specifically, acrylic acid, methacrylic acid, itaconic acid, maleic anhydride, maleic acid monomethyl ester, maleic acid monoethyl ester, or the like is used. . Among these unsaturated carboxylic acids, acrylic acid and methacrylic acid are particularly preferably used. The copolymer of unsaturated carboxylic acid and ethylene may be a random copolymer or a graft copolymer of unsaturated carboxylic acid onto polyethylene, but a random copolymer is preferable from the viewpoint of transparency.

The ethylene-unsaturated carboxylic acid copolymer that can be a raw material of the ionomer of the present invention may contain a third component in addition to ethylene and the unsaturated carboxylic acid as described above,
As such a third component, unsaturated carboxylic acid esters such as ethyl acrylate, isobutyl acrylate, n-butyl acrylate, ethyl methacrylate, and vinyl esters such as vinyl acetate are used.

For these ethylene-unsaturated carboxylic acid copolymers, the ethylene content is 40 to 99% by weight, preferably 50 to 98% by weight, and the unsaturated carboxylic acid is present in an amount of 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. As the neutralizing component in the ethylene-unsaturated carboxylic acid copolymer, Na ⁺ , K ⁺ , Li ⁺ , Ca ⁺⁺ , Mg ⁺⁺ , Zn ⁺⁺ , Cu ⁺⁺ ,
^{Co ++, Ni ++, Mn ++} , 1 monovalent trivalent metal cation Al ^+++, etc., and / or, n- hexylamine, hexamethylenediamine, 1,3-bis aminomethyl cyclohexane, meta An organic amine such as xylenediamine can be exemplified. 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 components may be used alone or in combination of many.

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%, particularly preferably 20 to 85% is used. The melting point of such ionomers is generally 70-100.
It is about ℃. The flow characteristics used are those having a melt flow rate of 0.1 to 200 dg / min measured at 190 ° C and a load of 2160 g.

The ethylene copolymer used as a mixture with the ionomer in the present invention is an ethylene copolymer having an epoxy group in the side chain, and specifically, ethylene and glycidyl acrylate or glycidyl methacrylate (hereinafter glycidyl (meth) acrylate). Or) a copolymer with glycidyl ether. (Hereinafter, a copolymer of the above ethylene and glycidyl (meth) acrylate or glycidyl ether is referred to as "ethylene / glycidyl compound copolymer".
Sometimes called. ) 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 monomers constituting the ethylene / glycidyl compound copolymer do not have to be two components. As another monomer component, a third component such as unsaturated carboxylic acid ester or vinyl ester may be included. 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 ethylene content of
40 to 99% by weight, preferably 50 to 98% by weight, 0.5 to 2 of glycidyl (meth) acrylate or glycidyl ether
0% by weight, preferably 1-15% by weight, and 0% by weight of the third component such as unsaturated carboxylic acid ester or vinyl ester.
Those of 49.5% by weight, preferably 0-40% by weight are suitably used. If the content of the glycidyl compound is too small, the effect of improving the mechanical strength of the ionomer at high temperature due to crosslinking is small, and if the content is too large, the crosslinking tends to be non-uniform, so an appropriate content. It is desirable to adjust to.

As the ethylene / 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.

The copolymer has a melt flow rate of 0.1 to 200 dg / min measured at 190 ° C. under a load of 2160 g.

In the present invention, the ionomer and the ethylene / glycidyl compound copolymer can be mixed in advance under non-reacting conditions to form a composition of both prior to crosslinking. Mixing can be performed by solids such as powder and pellets. The composition thus obtained is easily cross-linked by the reaction under melt-kneading and is used as a raw material for the cross-linked ionomer because a cross-linked ionomer is obtained, and both are melt-kneaded in a molding device as described later. Thus, since crosslinking and molding of the crosslinked ionomer can be continuously performed in the same step, it can be directly used as a raw material for a crosslinked ionomer molded product.

The reaction mechanism of the ionomer component and the ethylene / glycidyl compound copolymer in the present invention is such that the carboxyl group of the ionomer component reacts with the epoxy group of the side chain of the ethylene copolymer and the interion chain of the ionomer is the ethylene copolymer. It is considered that a crosslinked body is formed by covalently bonding via the. 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 formed by the reaction, and therefore foaming by by-products is not involved.

The method for producing a crosslinked ionomer of the present invention is characterized in that the ionomer and the ethylene / glycidyl compound copolymer are reacted under melt kneading. The reaction between the ionomer and the ethylene / glycidyl compound copolymer occurs without melting and kneading, for example, by dissolving both components in an appropriate solvent and mixing, but this method has a slow reaction rate and a solvent separation step. It is not economically desirable because it requires Melt-kneading 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 a screw extruder, a roll mixer, a Banbury mixer.

The use ratio of the composition for producing the crosslinked ionomer or the ionomer and the ethylene / glycidyl compound copolymer used in the production of the crosslinked ionomer is the content of the carboxyl group and the epoxy group of both components, and the mechanical strength at the target temperature. Ionomer 10 depends on the degree of improvement
0.3 to 4.5 parts by weight of the ethylene / glycidyl compound copolymer is based on 0 part by weight. If the proportion of the ethylene / glycidyl compound copolymer used is too low, the effect of improving the mechanical strength at high temperatures is small, and if the proportion of the ethylene / glycidyl compound copolymer is too high, not only the thermoformability is impaired, but also the excellent properties of the ionomer are Will be lost. Therefore, for applications that require a melt flow such as extrusion after the crosslinking reaction, it is necessary to determine the ratio of use of both in order to obtain a crosslinking reaction product with good flow. For example, when ethylene copolymerization is used as a raw material for both, the melt flow rate of the crosslinking reaction product is 0.001 to 30 dg / min,
In particular, it is preferable to select the use ratio of both so as to be 0.01 to 20 dg / min.

The crosslinked ionomer crosslinked with the ethylene / glycidyl compound copolymer thus obtained retains the excellent properties of the ionomer and has significantly improved heat resistance as compared with the non-crosslinked ionomer, and the crosslinked polymer However, it is possible to manufacture those having flow characteristics that enable thermoforming. Therefore, it is possible to manufacture a molded product by once pelletizing it and then applying various molding methods.

However, in the present invention, there is an advantage that such a pelletizing step can be omitted and the molding can be continuously performed after the crosslinking reaction. That is, if a continuous molding device having a plasticizing and mixing function of resin is used, by supplying the ionomer and the ethylene / glycidyl compound copolymer to the device, they are cross-linked and cross-linked by melt-kneading of both in the molding device. The ionomer can be continuously molded in the same step. This is because the ionomer cross-linking method utilizes a reaction in which by-products such as water and volatile gas are not generated by the cross-linking reaction, and both components to be reacted are olefinic thermoplastic resins and have a melting point range. This is because the crosslinking reaction and the molding can be performed simultaneously and easily because both are available in the form of pellets suitable for supplying the thermoplastic resin to the continuous molding device. As a molding apparatus having a resin melt mixing function, there are an inflation film molding machine using a screw extruder, a T die sheeting apparatus, an injection molding apparatus, an injection blow molding apparatus, and the like.

In the method for crosslinking an ionomer of the present invention, it is not necessary to perform crosslinking in the presence of only two components, an ionomer and an ethylene / glycidyl compound copolymer. As long as it does not interfere with the reaction, a polymer, a filler, various additives, etc. can be present as the third component. In particular, by adding an olefinic copolymer or the like that does not participate in the crosslinking reaction, it is possible to solve the problems such as the reduction of the surface gloss of the molded product which is caused by the crosslinking of the ionomer.

It is also possible to form a crosslinked foamed ionomer by adding a blowing agent to the ionomer and the ethylene / glycidyl compound copolymer and kneading them.

According to the present invention, in order to produce a molded article of an ionomer crosslinked with an ethylene / glycidyl compound copolymer, a method of reacting both components as described above under melt kneading is economically advantageous, but the method is It is not limited to For example, an ionomer and an ethylene / glycidyl compound copolymer are each made into a fine powder form, and then mixed in the powder form as they are, and then subjected to heat compression molding or rotary thermoforming to obtain a crosslinked ionomer molded product. You can also According to this method, it is possible to obtain a molded ionomer product having a high crosslink density and being particularly excellent in mechanical strength at high temperatures.

Various stabilizers, inorganic fillers, pigments, dyes, antistatic agents, anti-UV agents, lubricants and other additives can be added to the crosslinked ionomer of the present invention. Further, it can be used by blending with various thermoplastic resins. For example, it is possible to add an olefin-based copolymer that does not participate in the crosslinking reaction in order to improve the surface gloss, or to re-add the ionomer after completing the crosslinking reaction and consuming the epoxy group.

Molded bodies include films, sheets, bottles, cans, lid materials,
Examples include injection molded products, pipes, foams and the like. Of course, these molded bodies do not have to be composed only of the crosslinked ionomer, and can be formed into a shape such as a laminate with another substrate.

The cross-linked ionomer according to the present invention retains the excellent characteristics of the ionomer, while improving its disadvantageous mechanical strength at high temperatures. Compared with conventional cross-linked products of peroxide, odor, coloring, and foaming are not generated, and the cross-linking density is uniform, so less gels, lumps, and other substances that impair the external appearance are less mixed. Further, the cross-linked product by radiation such as an electron beam has a high cross-linking density on the surface side of molding and the cross-linking density decreases as it goes inside, so that it is limited to relatively thin molded products such as sheets and films. The crosslinked ionomer of the present invention is excellent in that not only a film or sheet but also a molded product having a large wall thickness or a molded product having a complicated shape can be obtained because the crosslinking density is uniform over the entire molded product.

Furthermore, the crosslinked product according to the present invention has the characteristics of flexibility, impact resistance, and stretchability that the ionomer has because the interstices of the ionomer are crosslinked through the olefin copolymer having a flexible molecular chain. Is dripping Compared to cross-linked products by cross-linking method in which polymer chains are directly bonded such as cross-linking with peroxide or electron beam, and ionomer cross-linked products with epoxy resin that cross-links polymer chains through rigid molecular chains The crosslinked ionomer product of the present invention is excellent in flexibility, impact resistance and stretchability. In particular, the tensile properties are not significantly reduced as compared with the non-crosslinked ionomer used as a raw material. The crosslinked ionomer of the present invention generally retains at least 50% or more of the elongation of the raw material ionomer. This is a great feature of the crosslinked ionomer of the present invention.

From the above characteristics, the crosslinked ionomer according to the present invention can be used for packaging films, adhesive films, automobile interior materials, exterior materials, golf ball skins, various tubes, molded articles such as tools, and sports shoe soles. Used for foamed molded products. Further, it can also be used as a laminate with a resin film having a gas barrier property.
It can also be used as a high-strength, high-heat-resistant resin composition having impact resistance by mixing with polyamide, polyester or the like.

[Examples] The present invention is described below with reference to examples, but the present invention is not limited to these examples.

The method for testing the molded product made of the ionomer used in this example is as follows.

Measuring method Melting point: Melt flowability (MFR) is JI by measuring crystalline melting point (DSC)
It was measured by SK-6710 at a load of 2160 g and a measurement temperature of 190 ° C.

Tensile strength (yield point stress, tensile strength at break, elongation): Based on JIS K-7113-1977, a test piece with a thickness of 2 mm and No. 3 deformation was measured at a tensile speed of 200 mm / min.

Thermal load creep test: 50m in length, consisting of the ionomer molding according to the present invention
A load creep test sample was prepared by applying a load of 100 g to a test piece measuring m, width 20 mm, and thickness 1 mm. Put this sample in the oven, 70 ℃ at a constant heating rate of 30 ℃ / hour
The temperature was raised from.

The temperature at which the load stretches or breaks due to this temperature rise and the load falls is defined as the load drop temperature, and this temperature is the degree of heat resistance of the sheet (degree of high mechanical strength at high temperatures).
Was used as a scale.

Heat-resistant fusion seal test Two crosslinked ionomer films of 100 μm in thickness according to the present invention were heat-sealed at a temperature of 220 ° C. and a pressure of 2 kg / cm ² with a heat sealer having a seal portion having a width of 5 mm and a length of 30 cm. Fusion). At this time, the time of heat sealing is changed to measure the time required for the heat sealing portion to be melted by heat. The heat-sealing time required for hot-melt cutting is used as a measure of the mechanical strength at high temperature. It is indicated that the longer the thermal fusing time, the better the mechanical strength at high temperature.

Maximum deep drawability test Using a vacuum packaging machine (Skin Tight Packer: Shin Meiwa Co., Ltd.), a cylindrical paper tube piece having an outer diameter of 96 mm, an inner diameter of 76 mm, and a height of 50 mm is composed of the ionomer composition according to the present invention. Thickness 15
Skin was wrapped while heating with an infrared heater using a 0 μm inflation film. This operation was repeated while gradually increasing the height of the paper tube piece until the film was broken, and the limit of the height of the stretchable paper tube piece was measured and set as the maximum drawing depth.

Examples 1 to 3 and Comparative Example 1 A resin melting and kneading apparatus with a capacity of 50 ml equipped with two rotating rotors (Laboplast mill: manufactured by Toyo Seiki Co., Ltd.)
The amount of the ionomer 1 (60% Na ⁺ ion neutralized product of ethylene-methacrylic acid copolymer (methacrylic acid content 15% by weight), MFR0.9) pellets was added at 180 ° C, 60 min / min.
Kneaded by rotation. A stable kneading torque was reached about 1 minute after the addition of the pellets. As shown in Table 1 below, when the stable torque was reached, as an ethylene / glycidyl compound copolymer, 0.5 to 5 parts by weight of ethylene vinyl acetate-glycidyl methacrylate copolymer (vinyl acetate 5 Wt%, glycidyl methacrylate 8
Wt%, MFR 6dg / min) pellets were added. Immediately after the addition of the ethylene copolymer, the kneading torque increased, and the progress of the crosslinking reaction was confirmed. The increase in kneading torque was greater as the amount of the ethylene copolymer added was larger,
In each case, the reaction was completed within 1 to 2 minutes of the addition, and a stable torque was reached. During the reaction, no volatile component was generated from the resin, foaming of the resin, generation of odor, etc., and the kneaded product was transparent. Kneading was stopped 10 minutes after the olefin copolymer was added, and the reaction product was taken out. A mass of the reaction product is pressed by a heat press molding machine at 160 ° C. for 5 minutes at a pressure of 50 kg / cm ² to 1 mm.
It was formed into a thick sheet. All the sheets were transparent and had no coloring, foaming or odor. When heat resistance (mechanical strength at high temperature) of this sheet was measured by a thermal load creep test, improvement in heat resistance was observed in all cases as compared with the non-crosslinked ionomer of Comparative Example 4. However, the composition of Comparative Example 1, in which the ethylene / glycidyl compound copolymer was added in a large amount, had a large increase in torque during kneading, and thus was somewhat difficult to process. The results are shown in Table 1.

Comparative Examples 2 to 3 In Examples 1 to 3, 11 to 25 parts by weight of ethylene-vinyl acetate-glycidyl methacrylate copolymer pellets were added per 100 parts by weight of the ionomer. The increase in the kneading torque was remarkably high as compared with Examples 1 to 3, and part of the resin was crushed and powdered during the kneading. A lump containing the reaction product powder was formed into a 1 mm thick sheet by a hot press under the same conditions as in Examples 1 to 3. The sheet was transparent and did not show coloring, foaming, or odor, but the sheet taken out from the hot press did not shrink or curve into a flat sheet, and it was considered that ordinary thermoforming was impossible. When the heat resistance of this sheet was measured by a thermal load creep test, the heat resistance was good. The results are shown in Table 1.

Comparative Example 4 A sheet having a thickness of 1 mm was prepared in the same manner as in Examples 1 to 3 using the pellets of the non-crosslinked ionomer 1 used as the raw material of Examples 1 to 3. The sheet is transparent and has an odor,
There was no coloring or foaming, and there was almost no difference from the sheet appearance of Examples 1 to 3. When a thermal load creep test was performed on this sheet, the load started to grow from around the melting point (90 ° C) of Ionomer 1, and the load dropped at 100 ° C. The results are shown in Table 1.

Examples 4-6, Comparative Example 5 A single screw extruder having a screw diameter of 30 mm and a length-to-diameter ratio (L / D) of 32 was placed on an ionomer 2 (ethylene-
Of methacrylic acid copolymer (methacrylic acid content 10% by weight)
50mol% neutralized (by Na ⁺ ) ionomer, melting point 95 ℃, MF
R 1.3 dg / min) pellets, the ethylene / glycidyl compound copolymer used in Examples 1 to 3, and the (ethylene-vinyl acetate-glycidyl methacrylate terpolymer) pellets are shown in Table 2 in advance. The mixture was dry-blended at a ratio and fed, and kneaded and extruded at a screw rotation speed of 50 rotations / minute and a resin temperature in the extruder of 200 ° C., and strands coming out of the extruder were cut with a cutter to obtain crosslinked ionomer pellets. The extrusion rate was 4.2 kg / hour. The strands from the extruder were colorless and transparent, and had no foaming, coloring, or odor. The surface of the strand was smooth, and no surface roughness due to foreign matter such as spots was observed. The resin pressure at the tip of the extruder increased as the proportion of ethylene / glycidyl compound copolymer increased, indicating that ionomer crosslinking occurred. The MFR value of the pellets also showed that crosslinking occurred.

The crosslinked ionomer pellets obtained here were formed into sheets having a thickness of 1 mm and 2 mm, respectively, by the method described in Examples 1 to 3. The sheet was colorless and transparent, and had no odor or foaming. For this sheet, the mechanical strength at high temperature was evaluated by the thermal load creep test, and the tensile properties were measured. The heat load creep test showed that the mechanical strength at high temperature increased as the proportion of ethylene-glycidyl compound copolymer added increased. On the other hand, although these samples are cross-linked polymers, no reduction in tensile properties is observed as compared with non-cross-linked ionomers. In particular, as is clear from the comparison with the value of Comparative Example 6, the stress at yield point was almost the same as the original ionomer, the flexibility was maintained, and the elongation did not significantly decrease. However, the composition of Comparative Example 5, in which the ethylene / glycidyl compound copolymer was added in a large amount, had a high resin pressure of the extruder at the time of kneading and extrusion, and the obtained resin had a significantly low MFR and flow characteristics. Since it was bad, the workability was poor.
Table 2 shows the results.

Comparative Example 6 Only the ionomer 2 was supplied to the screw extruder used in Examples 4 to 6 and extrusion was performed under the same extruder conditions as in Examples 4 to 6. The resin pressure at the tip of the extruder was lower than in Examples 4 to 6, but the motor load of the extruder was almost the same as in Examples 4 to 6.

Sheets of 1 mm and 3 mm were prepared from the ionomer pellets in the same manner as in Examples 4-6. The sheet was colorless and transparent, and no difference in appearance, odor, or color from the sheets of Examples 4 to 6 was observed. Further, with respect to this sheet, the tensile properties and the load thermal creep test were measured in the same manner as in Examples 4 to 6. Table 2 shows the results.

Comparative Example 7 In the same extruder as in Examples 4 to 6, 100 pellets of an ethylene-methacrylic acid copolymer (methacrylic acid content 9% by weight, MFR 10 dg / min, melting point 98 ° C.) not neutralized with metal ions or the like were used. 3 parts by weight per 3 parts by weight of the ethylene / glycidyl compound copolymer pellets used in Examples 1 to 3 were previously drive-blended and supplied, and kneading and extrusion were performed under the same conditions as in Examples 4 to 6. Although the resin strands emerging from the extruder were transparent, the surface was markedly uneven, suggesting uneven crosslinking. MFR measurement was performed on the pellets obtained by cutting the strands.

A sheet having a thickness of 1 mm was prepared from the obtained resin pellets in the same manner as in Examples 4 to 6, and a thermal load creep test was conducted on the sheet. The same proportion of the olefin copolymer was added to the ionomer. The degree of improvement in heat resistance was less than that of the crosslinked crosslinked ionomer of Example 6.

 The results are shown in Table 2.

Examples 7 and 8 An ionomer 2 and an ethylene / glycidyl compound copolymer used in Examples 4 to 6 were added to an inflation film molding machine equipped with a 30 mm diameter single screw extruder.
The pellets were dry-blended in advance in the proportions shown in Table 3 and then fed, and the inflation film was molded at a resin temperature of 220 ° C. to obtain a tubular inflation film having a thickness of 100 μm. Molding of the blown film was easy, and there was almost no difference from the time of molding the blown film of the ionomer 2 shown in Comparative Example 8. The inflation film was transparent,
The surface of the film was frosted, and the appearance of the blown film was peculiar to the crosslinked resin. The film contained almost no foreign matter such as gel and lumps, and had a good appearance.

When a heat-resistant fusion-sealing test was conducted on this film, both films were first cut by heat sealing for a long time as compared with the film of Ionomer 2 shown in Comparative Example 8, and the mechanical strength at high temperature was improved as compared with the ionomer. I found out. The results are shown in Table 3.

Comparative Example 8 Pellets of ionomer 2 were supplied to the same inflation film molding machine as in Examples 7 and 8 to obtain an inflation film having a thickness of 100 μm under the same conditions as in Examples 7 and 8. Molding of the film was almost as easy as in Examples 7 and 8, and the load on the motor during molding was almost the same as in Examples 7 and 8. The film was transparent and had a glossy surface.

When this film was subjected to a heat-resistant fusion-sealing test, it melted with a short-time seal, and its mechanical strength at high temperature was poor.

 Table 3 shows the results.

Examples 9 to 13 Pellets of an ionomer and an ethylene / glycidyl compound copolymer were fed to the single-screw extruder used in Examples 4 to 6 at a ratio shown in Table 4, and the screw rotation speed was 50 rotations / minute. The resin temperature in the extruder was 220 ° C., and the mixture was kneaded and extruded to obtain crosslinked ionomer pellets. The extrusion rate was 4.2 Kg / hour. All the strands from the extruder were colorless and transparent, and had no foaming, coloring, or odor.

The crosslinked ionomer pellets obtained here were supplied to the inflation film molding machine used in Examples 7 and 8 to carry out inflation film molding at a resin temperature of 220 ° C. to obtain a tubular inflation film having a thickness of 150 μm. . Inflation film molding was easy and a transparent film was obtained. The surface of the film varied from a frosted glassy surface to a glossy surface depending on the type of ionomer used, but in each case, there were no large irregularities due to coarse particles such as gel. The film was subjected to a heat-resistant fusion seal test and a maximum deep drawability test. In each case, the sealing time until thermal cutting is longer than that of the uncrosslinked ionomer films of Comparative Examples 9 to 11,
The mechanical strength at high temperature was improved. Further, although the maximum drawing depth was similar to that of the uncrosslinked ionomer, the melt drawability was maintained. The results are shown in Table 4.

Comparative Examples 9 to 11 The ionomer (uncrosslinked) 150 μm thick film used in Examples 9 to 13 was prepared at the resin temperature of 220 ° C. using the same blown film molding machine as in Examples 9 to 13. The film was transparent and had a good surface gloss.
This film was subjected to heat-resistant fusion sealability and maximum deep drawing test. The fusing time was shorter than that of the crosslinked ionomer, and the mechanical strength at high temperature was poor. The results are shown in Table 4.

[Effects of the Invention] A composition comprising an ionomer and an ethylene / glycidyl compound copolymer according to the present invention easily forms a crosslinked ionomer by melt-kneading, and is used in a conventional ionomer crosslinking method with an organic peroxide. In comparison, it does not cause odor, coloring, foaming, or the appearance of a molded article such as gel or lumps, and thus gives a crosslinked product of excellent quality. Further, the cross-linking operation is easier than the ionomer cross-linking method using an epoxy resin. Further, by selecting the mixing ratio of the ionomer and the ethylene / glycidyl compound copolymer within a specific range, a composition was obtained in which the characteristics of the ionomer such as excellent processability were fully utilized.

From these characteristics, the ionomer cross-linking method of the present invention can extremely easily and economically carry out the cross-linking of the ionomer and the production of the cross-linked molded article by directly using the usual thermoplastic resin continuous molding apparatus.

Further, compared with the crosslinking method using an energy ray source such as electron beam irradiation, it is not necessary to use an expensive special device and is economically superior. From the above, the ionomer cross-linking method of the present invention was able to greatly improve the problems of quality and economy, which could not be solved by the conventional ionomer cross-linking methods.

Further, the crosslinked ionomer molded article according to the present invention substantially impairs the excellent characteristics of the ionomer such as heat sealability, heat adhesion, low odor, hygiene, transparency, oil resistance, impact resistance, and abrasion resistance. However, the molded article is improved in its low mechanical strength at high temperature, which is its drawback.

Further, this molded product is a high quality crosslinked product which does not have a bad surface appearance such as odor, coloring, and lumps like an ionomer molded product crosslinked by an organic peroxide. Further, the molded product of the present invention is not limited to a thin molded product such as a film or a sheet like an ionomer molded product crosslinked by an electron beam, and can be a molded product having a large wall thickness or a complicated shape. . Further, although it is a crosslinked product, the molded product of the present invention has flexibility, impact resistance, and stretchability, and is superior in quality in these respects to a molded product of an ionomer crosslinked by a conventional crosslinking method. Therefore, it is effectively used for applications such as flexible packaging films and sports equipment.

Claims (4)

(57) [Claims] 1. An ethylene-unsaturated carboxylic acid copolymer having an unsaturated carboxylic acid content of 2 to 40% by weight, at least a part of which is neutralized with a metal cation and / or an organic amine. Becomes, melt flow rate (190
Ethylene, glycidyl having a melt flow rate of 0.1 to 200 dg / min and a glycidyl (meth) acrylate or glycidyl ether content of 0.5 to 20 wt% relative to 100 parts by weight of an ionomer of 0.1 to 200 dg / min (° C, 2160 g load). A composition, which is formed by mixing 0.3 to 4.5 parts by weight of a copolymer with (meth) acrylate or glycidyl ether, to form a crosslinked ionomer by a reaction under a melting condition. 2. An ethylene-unsaturated carboxylic acid copolymer having an unsaturated carboxylic acid content of 2 to 40% by weight, wherein at least part of the carboxyl groups is neutralized with a metal cation and / or an organic amine. Becomes, melt flow rate (190
Ethylene, glycidyl having a melt flow rate of 0.1 to 200 dg / min and a glycidyl (meth) acrylate or glycidyl ether content of 0.5 to 20 wt% relative to 100 parts by weight of an ionomer of 0.1 to 200 dg / min (° C, 2160 g load). A method for producing a crosslinked ionomer, which comprises reacting 0.3 to 4.5 parts by weight of a copolymer with (meth) acrylate or glycidyl ether under melt-kneading. 3. The cross-linked ionomer has a melt flow rate
The method for producing a crosslinked ionomer according to claim 2, which has a concentration of 0.001 to 30 dg / min. 4. The method for producing a crosslinked ionomer according to claim 2, wherein the elongation of the crosslinked ionomer is 50% of the elongation of the raw material ionomer.