JP3406364B2 - Polymer composition - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a polymer composition excellent in mechanical strength and impact resilience.

[0002]

2. Description of the Related Art Ionomer, which is an ethylene / unsaturated carboxylic acid copolymer, is widely used as a golf ball cover material, taking advantage of its high impact resilience. It is also known that a cover material having high impact resilience can be obtained especially when an alkali metal ionomer and a polyvalent metal ionomer are used in combination. However, there is a limit in improving the impact resilience by combining only ionomers.

It is known from Japanese Patent Publication No. 56-383 that a polymer composition comprising a thermoplastic polymer having a carboxyl group and water glass is excellent in toughness and heat resistance. In this publication, an example of using an ionomer of an ethylene / unsaturated carboxylic acid copolymer as the above-mentioned thermoplastic polymer is shown, but since it is intended for foams and heat-resistant materials, use of water glass Only cases with a very high proportion are being considered. Further, this publication does not consider peculiar physical properties such as impact resilience at all.

The present inventors have focused their attention on this technology in the course of conducting extensive research on modification of ethylene copolymers with inorganic substances, and in particular, of ethylene / unsaturated carboxylic acid copolymers and silicic acid alkali metal salts. Detailed studies were conducted on the blend system. As a result, it was found that when a large amount of water glass was mixed with the ionomer as described above, the melt viscosity was extremely high and the moldability was significantly impaired.

However, it has been found that by strictly controlling the amount of alkali metal silicate, a composition having unexpectedly high impact resilience and excellent moldability can be obtained.
The present invention has been reached.

[0006]

The present invention provides an ethylene / unsaturated carboxylic acid copolymer or its ionomer (A).
And a silicic acid alkali metal salt (B) containing 0.1 to 8 equivalents of an alkali metal component with respect to 1 equivalent of a free or metallized carboxyl group in (A).

The present invention also relates to an ethylene / unsaturated carboxylic acid / unsaturated carboxylic acid ester copolymer or its ionomer (C), and to the equivalent of a free or metallized carboxyl group in (C) of 0. It relates to a polymer composition comprising an alkali metal silicate (B) containing 1 to 30 equivalents of an alkali metal component.

[0008]

In the present invention, when an ethylene / unsaturated carboxylic acid copolymer, an ethylene / unsaturated carboxylic acid / unsaturated carboxylic acid ester copolymer or an ionomer thereof is blended with a silicic acid alkali metal salt in a specific amount ratio. This is based on the finding that the tensile strength at break and impact resilience of this composition are remarkably improved.

For example, as shown in the examples described below, the tensile strength at break of the ethylene / unsaturated carboxylic acid / unsaturated carboxylic acid ester copolymer was 117 kgf / cm ² and the impact resilience was 40% (Comparative Example 1). However, by adding alkali metal silicate corresponding to 0.9 mole times alkali per carboxyl group, the tensile strength at break is 351k.
It is possible to improve gf / cm ² and impact resilience to 61% (Example 1).

A resin obtained by neutralizing an ethylene / unsaturated carboxylic acid copolymer or an ethylene / unsaturated carboxylic acid / unsaturated carboxylic acid ester copolymer with a compound of an alkali metal, an alkaline earth metal or another metal is Generally called an ionomer, this resin improves tensile strength at break and impact resilience due to the formation of ionic crosslinks between polymer chains. For example, although not a strict contrast, the unneutralized ethylene / unsaturated carboxylic acid copolymer having a tensile strength at break of 242 kgf / cm ² and impact resilience of 31% (Comparative Example 2) is The tensile strength at break is 275 kgf / cm ² and the impact resilience is 57% due to neutralization by
(Comparative example 3).

In the present invention, the alkali metal silicate is used as an ionizing crosslinking agent for the ethylene / unsaturated carboxylic acid copolymer or the ethylene / unsaturated carboxylic acid / unsaturated carboxylic acid ester copolymer. Unexpectedly superior to the conventional ionized cross-linking agent, the tensile strength at break and the impact resilience are improved. For example, the tensile strength at break of the resin of Comparative Example 2 is 284 kgf / cm ^2.
Also, the impact resilience can be improved to 64%.

Further, the above-mentioned improvement in tensile strength at break and impact resilience can be achieved even when a conventional ionomer is mixed with an alkali metal silicate.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The polymer component in the present invention is an ethylene / unsaturated carboxylic acid copolymer or its ionomer (A) or an ethylene / unsaturated carboxylic acid / unsaturated carboxylic acid ester copolymer or its ionomer (C). )
Is.

The unsaturated carboxylic acid component in (A) or (C) includes unsaturated monocarboxylic acid, unsaturated dicarboxylic acid, unsaturated dicarboxylic acid anhydride, unsaturated dicarboxylic acid monoester and the like. More specifically, unsaturated monocarboxylic acids such as acrylic acid and methacrylic acid, unsaturated dicarboxylic acids such as maleic acid and fumaric acid, maleic anhydride, itaconic anhydride, norbornene-2,3-
Examples thereof include unsaturated dicarboxylic acid anhydrides such as dicarboxylic acid anhydrides, unsaturated dicarboxylic acid monoesters such as monomethyl maleate, monoethyl maleate, and monoisobutyl maleate.

The unsaturated carboxylic acid ester component in (C) includes methyl acrylate, ethyl acrylate, isobutyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate and methacrylic acid. Examples thereof include isobutyl acid and dimethyl maleate.

The ethylene / unsaturated carboxylic acid copolymer as the component (A) has an ethylene content of 65 to 9
Suitable is 9% by weight, preferably 70 to 94% by weight, and an unsaturated carboxylic acid content of 1 to 35% by weight, preferably 6 to 30% by weight.

In the component (C), when the unsaturated carboxylic acid component is an unsaturated monocarboxylic acid, the ethylene content is 50 to 98% by weight, preferably 60 to 94% by weight, and the unsaturated carboxylic acid is contained. It is suitable that the amount is 1 to 35% by weight, preferably 2 to 30% by weight, and the unsaturated carboxylic acid ester content is 1 to 40% by weight, preferably 5 to 30% by weight. When the unsaturated carboxylic acid component in the component (C) is unsaturated dicarboxylic acid, its anhydride, or its monoester, the ethylene content is 40.
-90 wt%, preferably 50-85 wt%, unsaturated carboxylic acid content 0.1-10 wt%, preferably 0.1.
5-5% by weight, unsaturated carboxylic acid ester content 10
Those having a composition in the range of -59 wt%, preferably 14-50 wt% are suitable.

If the ethylene content is less than the above range, it is difficult to obtain the one having excellent mechanical strength, which is not preferable. On the other hand, it is not preferable to use an unsaturated monocarboxylic acid having an excessively high content because the hygroscopicity becomes high. If an unsaturated dicarboxylic acid, its anhydride, its monoester, etc. are contained in a larger amount than the above range, the melt viscosity tends to be too high, and the moldability tends to be impaired.

The ethylene / unsaturated carboxylic acid copolymer in the component (A) can be obtained by copolymerizing ethylene and an unsaturated carboxylic acid at high temperature and high pressure. The ethylene / unsaturated carboxylic acid / unsaturated carboxylic acid ester copolymer in the component (C) can be obtained by copolymerizing each raw material under high temperature and high pressure. This copolymer can also be produced by similarly synthesizing an ethylene / unsaturated carboxylic acid ester copolymer by copolymerization under high temperature and high pressure, and graft-polymerizing an unsaturated carboxylic acid thereto. These copolymerization methods using a radical initiator are already widely known.

Instead of using the above copolymers as the component (A), their ionomers can be used. There is no particular limitation on the metal ion in the ionomer, and alkali metals such as lithium, sodium, potassium and cesium, alkaline earth metals such as calcium, magnesium and barium, and transitions such as zinc, copper, cobalt, nickel and iron. An ionomer having metal ions such as metal and aluminum can be used. The degree of neutralization with metal ions is arbitrary, for example, 0-9.
Although the amount of 0 mol% can be used, it is not advantageous to use the one having a too high degree of neutralization, and therefore it is generally preferable to use the one having a degree of neutralization of about 60 mol% or less.

As the component (A) or the component (C),
Considering workability and mechanical strength, 190 ° C, 216
Melt flow rate at 0 g load is 0.01 to 2
It is preferable to use one having a viscosity of 000 g / 10 minutes, preferably about 1 to 500 g / 10 minutes.

The alkali metal silicate used in the present invention has a general formula M ₂ O.nSiO ₂ .x H ₂ O (1) (M is an alkali metal such as sodium or potassium, n is 0.1 to 10). , X is a compound represented by 0 to 100). Especially when M is sodium, water glass or what is known as sodium metasilicate can be used, and the typical one is JI.
Shown in SK 1408. Of course, in the present invention, not only those specified by such a standard but also M ₂
Various ratios of O and SiO ₂ can be used, for example, sodium orthosilicate, sodium disilicate, sodium tetrasilicate and the like can be used, but in consideration of the physical properties of the composition, n is 0.3 to 5. It is desirable to be in the range of 0. In addition, x is arbitrary, and may be used after dehydration is performed in advance to reduce water content, or conversely, it may be used in the form of an aqueous solution of alkali metal silicate. In general, in order to reduce the load of dehydration on the kneading equipment, it is preferable to use solid alkali metal silicate.

When the alkali metal silicate (B) is blended with (A), it is 0.1 to 8 equivalents, preferably 0.1 to 1 equivalent to 1 equivalent of the free or metal-chlorinated carboxyl group in (A). (B) corresponding to 5 to 5 equivalents of the alkali metal component is blended. Then, with respect to 1 equivalent of the free or metal-chlorinated carboxyl group in the composition, the component (B) or the alkali metal component derived from the component (B) and the component (A) is 0.3 to 8 equivalents, preferably 0.5-5 equivalents,
More preferably, the component (B) is blended so as to be 0.8 to 3 equivalents. If the blending amount of (B) is small, a sufficient modifying effect is not recognized, while if the blending amount is too large, the melt viscosity becomes too high and the workability deteriorates, which is not preferable.

On the other hand, the alkali metal silicate (B) is added to (C)
When a large amount of the component (B) is blended, the workability is less deteriorated and a larger amount than the above is acceptable. That is, 0.1 to 30 equivalents, preferably 0.5 to 8 equivalents, and more preferably 0.8 to 5 equivalents of alkali metal components are added to 1 equivalent of the free or metal-chlorinated carboxyl group in (C). It is preferable to add the corresponding component (B).

However, the unsaturated carboxylic acid component (C) is
In the case of an unsaturated dicarboxylic acid, its anhydride or its monoester, the tendency of the melt viscosity to increase by blending the component (B) is high, so 5 parts or less, preferably 2 parts or less of the alkali metal component is preferably added per 1 equivalent of the carboxyl group. It is preferable that the amount is equivalent or less.

In the present invention, when the unsaturated carboxylic acid is a dicarboxylic acid anhydride, it is treated as having two carboxyl groups per acid anhydride group.

The polymer composition of the present invention is obtained by melt-kneading (A) or (C) and (B) using an ordinary kneading device such as a pressure kneader, Banbury mixer, extruder or the like. Can be easily obtained.

If necessary, the polymer composition of the present invention may contain inorganic substances such as talc, calcium carbonate, silica, titanium oxide, zinc oxide, barium sulfate, glass fiber, ceramic fiber and carbon fiber. Further, various additives such as antioxidants, pigments, dyes, weather resistance stabilizers, UV inhibitors, lubricants, antistatic agents, flame retardants and the like can be added.

[0029]

EXAMPLES Examples will be shown below, but the present invention is not limited to these examples. (1) Performance Evaluation In the following examples and comparative examples, the tensile strength at break and the impact resilience of the resin compositions were measured by the following methods,
These performances were evaluated. (1-1) Tensile strength at break 150 * 15 at a resin temperature of 180 ° C with a press molding machine
A 0 * 2 mm press sheet was molded, a test piece was punched out with this square plate, and a test was conducted according to JIS K7113 for measurement. (1-2) Thickness of 12.6 using a press molding machine at a resin temperature of 180 ° C. for impact resilience.
mm, a diameter of 29.0 mm, a right cylindrical test piece is prepared,
The test was conducted in accordance with JIS K6301 for measurement.

(2) Sample First, the raw materials used for preparing the composition of the present invention are as follows. Polymer (A) or (C) C-1 ethylene / methacrylic acid / isobutyl acrylate copolymer composition: 72/8/20 wt% A-1 ethylene / methacrylic acid copolymer composition: 85/15 wt % A-2 ethylene / methacrylic acid copolymer composition: 90/10 wt% 50 mol% sodium-neutralized product C-2 ethylene / methyl acrylate / maleic acid monoethyl ester copolymer composition: 74.7 / 23 /2.3 wt% sodium silicate (B) B-1 Water glass aqueous solution composition: Na ₂ O / SiO ₂ / H ₂ O = 17/35/48
wt% B-2 sodium orthosilicate (flakes) Composition: Na ₂ O / SiO ₂ / H ₂ O = 47/23/30
wt%

Examples 1 to 7 Kneading was performed using a Labo Plastomill kneader manufactured by Toyo Seiki. The polymer (A) or (C) is charged into a Labo Plastomill kneader heated to 100 ° C to 120 ° C. After the resin has gelled, sodium silicate is added dropwise. After the dropping is completed,
After heating to 220 ° C., kneading was performed for 5 minutes. The physical properties of the obtained resin composition were evaluated. The measurement results of these physical properties are as shown in Table 1.

Comparative Examples 1 to 4 The tensile strength at break and impact resilience of a thermoplastic resin containing no sodium silicate were evaluated. In both cases, the tensile strength at break and impact resilience are inferior to those containing sodium silicate.

Comparative Examples 5 and 6 LDPE, which is a thermoplastic resin having no carboxyl group, was used in place of the thermoplastic resin of Example 2, and the same amount of sodium silicate as in Example 2 was used. Was kneaded, and the physical properties of the resin composition were evaluated. The breaking strength of a thermoplastic resin having no carboxyl group such as LDPE decreases when sodium silicate is added. Also, the impact resilience is reduced.

[0034]

[Table 1] * 1 r = sodium silicate / carboxyl group of (A) or (C) (molar ratio) * 2 unit kgf / cm ² * 3 unit%

Comparative Example 7 Instead of sodium silicate of Example 2, Na ₂ The same kneading and physical property evaluation as in Example 2 were performed using CO ₃ . Even if the molar ratio of sodium to the carboxyl group of the thermoplastic resin is the same, the composition containing sodium silicate is Na ₂
It exhibits higher tensile strength at break and impact resilience than compositions containing CO ₃ . The results of these comparative examples are shown in Table 2.

[0036]

[Table 2] * 4: 5.5 parts added to 100 parts LDPE

[0037]

According to the present invention, it is possible to provide a polymer composition having excellent mechanical strength and impact resilience. The hardness of these polymer compositions can be adjusted by the polymer composition of the component (A) or the component (C) or the blending amount of the component (B). These compositions are also excellent in moldability, and various products can be manufactured by various molding methods such as extrusion molding, injection molding, blow molding, blow molding, and press molding. These are various malls, drainers, gaskets, automobile interior / exterior parts such as door materials, sporting goods such as core materials and cover materials for golf balls, making use of the above properties.
It can be used for construction civil engineering products, daily necessities, electrical parts, etc.

Claims (3)

(57) [Claims] 1. An ethylene / unsaturated carboxylic acid copolymer or its ionomer (A) and 0.1 per 1 equivalent of a free or metallized carboxyl group in (A).
A polymer composition comprising an alkali metal silicate (B) containing 8 to 8 equivalents of an alkali metal component. 2. The amount of the alkali metal component derived from the component (B) or the component (B) and the component (A) is 0.5 to 3 equivalents relative to 1 equivalent of the free or metallized carboxyl group in the composition. The polymer composition according to claim 1, which is in the range of. 3. An ethylene / unsaturated carboxylic acid / unsaturated carboxylic acid ester copolymer or its ionomer (C).
And a silicic acid alkali metal salt (B) containing 0.1 to 30 equivalents of an alkali metal component with respect to 1 equivalent of a free or metallized carboxyl group in (C).