JPS6079015A - Production of modified ethylene copolymer - Google Patents

Abstract

PURPOSE:To facilitate the production of a modified ethylene copolymer having metal ion crosslinkages, by reacting an ethylene/ethyl acrylate copolymer in an inert gas atmosphere in the presence of water and metal ions under specified conditions of temperature and pressure. CONSTITUTION:A relatively high MW ethylene/ethyl acrylate copolymer having an ethyl acrylate content of 1-40wt% is reacted in an inert gas atmosphere in the presence of water and metal ions (e.g., alkali metal or zinc ions) at a temperature of 200-500 deg.C and a pressure of 5-500kg/cm<2>. In this way, a modified ethylene copolymer having good hve, a low MW (<=30,000) and metal ion crosslinkages. The obtained modified ethylene copolymer can be suitably used as an emulsion adhesive, water-based paint, dispersing aid for pigments, plasticizer, lubricant, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a modified ethylene copolymer having metal ionic crosslinks from an ethylene-ethyl acrylate copolymer.

More specifically, the ethylene-ethyl acrylate copolymer was prepared in the presence of water and metal ions in an inert atmosphere at a temperature of 2.
The present invention relates to a method for producing a modified ethylene copolymer, characterized in that the reaction is carried out under conditions of 00 to 50.0°C and a pressure of 5 to 50 DKp/crl.

Conventionally, many methods for producing ethylene copolymers crosslinked with metal ions are known.

For example, as seen in Japanese Patent Publication No. 39-6810, ions have been cross-linked by reacting a water-soluble ionic metal compound with a copolymer of ethylene-α, β-ethylenically unsaturated carboxylic acids. There is a method to obtain a polyester copolymer.

In the above method, the highly corrosive property of carboxylic acid to metals is not a problem during the production of ethylene-carboxylic acid copolymer, and the neutralization reaction is carried out using rolls.
There are problems such as the possibility that the reaction between the carboxylic acid of the copolymer and the metal salt lacks uniformity.

In addition, as an improvement of the above method,
There is a publication No. 56. This method involves saponifying a copolymer of ethylene and α,β-type unsaturated carbo/acid ester with a basic metal compound in an aliphatic alcohol or an organic solvent containing an aliphatic alcohol. It is characterized by acid treatment of the reaction product,
These methods do not require complicated steps such as the use of organic solvents and acid treatment, and all of these methods yield only high molecular weight ionic crosslinked products.

11c% Publication No. 52-23673 discloses a copolymer of ethylene and an α,β-ethylenically unsaturated carboxylic acid ester selected from inpropyl (meth)acrylate and tert-butyl (meth)acrylate. and I of the periodic table,
Metal compounds such as acetates, formates, and oxides of metals having a valence of 1 to 3 in groups II, I, IV-, and A are melt-mixed and mixed in one step at a temperature of 200 to 320"C. A method for producing an ionically crosslinked ethylene copolymer is disclosed.

However, even in this method, the essential condition is that the copolymer used as the copolymer base is resistant to thermal decomposition of the polymer chains, and the metal compound used is also subject to thermal decomposition of the polymer chains. The purpose of this method is to produce a high molecular weight ionically crosslinked ethylene copolymer, since it must not be involved in or suppress the cleavage reaction.

On the other hand, recently, low molecular weight ethylene copolymers having ionic crosslinking have been in demand in various fields such as emulsion adhesives, raw materials for water-based paints, hot melt adhesives, and resin modifiers.

As a result of intensive research in view of the above points, the present inventors have found that a modified ethylene copolymer having a desired amount of metal ionic crosslinks, which has been arbitrarily reduced in molecular weight from an ethylene-ethyl acrylate copolymer, is produced in a one-step process. So, we found a way to directly manufacture it.

The first object of the present invention is to provide a method for producing a modified ethylene copolymer having metal ion crosslinks, which is arbitrarily reduced in molecular weight from a relatively high molecular weight ethylene-ethyl acrylate copolymer.

A second object of the present invention is to provide a method for producing a modified ethylene copolymer having a desired amount of metal ionic crosslinks.

A third object of the present invention is to provide a method for producing a modified ethylene copolymer with good hue.

Furthermore, the fourth object of the present invention is to prepare a modified ethylene copolymer having metal ion crosslinks of an ethylene-acrylic acid binary copolymer substantially free of unsaponified ethyl acrylate or an arbitrary amount of acrylic acid. An object of the present invention is to provide a method for producing a modified ethylene copolymer having metal ion crosslinking of an ethylene-ethyl acrylate-acrylic acid ternary copolymer in which ethyl remains. The present invention has been made to achieve the above object.

That is, according to the present invention, relatively high molecular weight ethylene-
The ethyl acrylate copolymer was heated in an inert atmosphere in the presence of water and metal ions at a temperature of 200-500°C and a pressure of 5-50°C.
By reacting under conditions of 500 h/cWL, the above-mentioned modified ethylene copolymer can be produced.

The ethylene-ethyl acrylate copolymer referred to in the present invention refers to a commercially available ethylene-ethyl acrylate copolymer having a relatively high molecular weight that can be easily obtained by, for example, a high-pressure copolymerization method known in the industry using a free radical catalyst. And,
Its melt index is approximately 300F/10m1n
Below, the content of ethyl acrylate in the molecular chain is approximately 1
-40% by weight or 5-30% by weight. In addition, the method of creating an inert atmosphere in the present invention is not particularly limited, but for example, a method of completely eliminating air by passing an inert gas such as nitrogen, carbon dioxide, argon, or helium through the reaction system is possible. Any suitable solvent may be used, and nitrogen is preferably used.

Furthermore, the reaction temperature and reaction pressure when carrying out the present invention are determined by the properties of the raw materials used, that is, the average molecular weight of the ethylene-ethyl acrylate copolymer, the content of ethyl acrylate,
The reaction temperature is 200-500°C, the reaction pressure is 5-50 DTip/cal, and the reaction time is 1-50 DTip/cal, although it is controlled by factors such as the degree of molecular weight reduction and the amount of coexisting water.
The duration is 10 hours, preferably 2 to 6 hours.

If the reaction temperature is less than 200°C, lowering of the molecular weight will occur. If the temperature exceeds 5DO°C, ethyl acrylate in the copolymer will volatilize, decarboxylation reactions, etc. will occur, and decomposition will occur. Violent behavior is not desirable.

The metal ions added in the present invention are preferably added in the form of an aqueous solution of a metal compound having a valence of 1 to 3, and the first ion group includes ■Na+, K'',
Li", 0MP+-1-, Ca++, Ba++, Z
n++.

Sb”, Cu+Mo, FeQ, 0 people (+++, pe
Among these, alkali metal ions are preferred, and among the metal compounds forming the source of the second ion group, water as a so-called basic metal compound is selected. Includes sodium oxide, magnesium hydroxide, potassium hydroxide, zinc hydroxide, calcium oxide, sodium methoxide, sodium ethoxide, magnesium oxide, nickel acetate, sodium carbonate, red sea bream sium, zinc acetate, etc., and aqueous solutions of these can be preferably used.

In order to achieve the above-mentioned purpose of producing a modified ethylene copolymer whose molecular weight has been arbitrarily reduced by the method of the present invention, it is necessary to use a relatively high molecular weight ethylene-ethyl acrylate copolymer as a raw material in an inert atmosphere. in the presence of water and metal ions at a temperature of 200-500℃ and a pressure of 5-500℃.
It is important to carry out the reaction under Kp/cnitD conditions, and among these reaction conditions, the most important factors include the presence of water and temperature conditions. Note that water in the present invention includes liquid, water vapor, and a mixture thereof.

The molecular weight of the ethylene-ethyl acrylate copolymer can be arbitrarily lowered by changing the above-mentioned temperature conditions and especially the amount of water. It is possible to produce a modified product of the original copolymer or a modified product of an ethylene-ethyl acrylate-acrylic acid ternary copolymer in which any amount of ethyl acrylate remains. For example, in the production of a modified ethylene-acrylic acid binary copolymer substantially free of unsaponified ethyl acrylate, the amount of water is 'l 400 mol or more, preferably 4
This is achieved by carrying out the reaction under conditions in the range of 0 to 1.5 D 0 mol.

However, since it is desirable that the amount of water added be as small as possible from the viewpoint of energy consumption cost, it is appropriately selected in consideration of the required physical properties and intended use.

The above-mentioned modified ethylene having low molecular weight ionic crosslinking generally has a viscosity average molecular weight of 30,000 or less, preferably 15,000 or less.
It is less than or equal to 0.

The viscosity average molecular weight of the present invention was determined by measuring the intrinsic viscosity [η] in a decalin solvent at 135° C. and using the following formula.

[η)=KMct 5 (K= 14.3X10 (dLy), (1= 0
．． 82'') Furthermore, an object of the present invention is to provide a method for producing a modified ethylene copolymer having a desired amount of metal ionic crosslinking, but the amount of metal ions added depends on the reaction temperature, reaction pressure,
While considering the influence of various factors such as reaction time, amount of water added, content of ethyl acrylate in the raw materials, degree of lowering of the molecular weight of the ethylene-ethyl acrylate copolymer, type and concentration of metal ions, etc. , the ethylene-ethyl acrylate copolymer should be selected so as to be ionically crosslinked in an amount of 5 to 80 mol%, preferably 10 to 70 mol%, based on the ethyl acrylate copolymer, depending on the properties of the solid state and the molten state. Desirable for its superior properties.

The purpose is to provide a method for producing copolymers, but
In order to obtain the modified ethylene copolymer with good hue, the reaction is carried out at an oxygen concentration of 5 ppm or less, preferably 3 ppm or less, particularly preferably 1 ppm or less, as measured by the usual Grady method. It is manufactured by performing the following steps.

The following method can be used to reduce the oxygen concentration in the reaction system to 5 ppm or less.

First, in order to eliminate oxygen dissolved in the water in the reaction system, inert gas is bubbled from the bottom of the reaction vessel to completely eliminate dissolved oxygen, and the air inside the reactor is heated with inert gas. This is achieved by repeating pressure and pressure release purge operations.

The effects of the present invention can be obtained, for example, from a relatively high molecular weight raw material ethylene-ethyl acrylate copolymer with an average molecular weight of several thousand to several hundred thousand to a low molecular weight modified ethylene with an average molecular weight of several thousand that does not substantially contain ethyl acrylate. In cases where the degree of molecular weight reduction is very large, such as in the production of copolymers,
most prominently demonstrated.

As mentioned above, the method of the present invention has the following features: (1)
A low molecular weight ionic crosslinked ethylene copolymer can be directly produced in a one-step process; θ) The molecular weight of the raw material ethylene-ethyl acrylate copolymer can be reduced and the residual amount of ethyl acrylate can be controlled as desired. G) A modified ethylene copolymer having a desired range of ionic crosslinking can be produced with respect to ethyl acrylate in the raw material ethylene-ethyl acrylate copolymer; (4) A modified ethylene copolymer with a good hue can be provided. Possible; It has many advantages as shown in the following.

The modified ethylene copolymer obtained by the method of the present invention can be used as adhesives such as emulsion adhesives and hot melt adhesives, paints such as water-based paints, or as lubricants for improving moldability, pigments, and fillers. Dispersion aids/coupling agents, various polymers/asphalt) - Wax modifiers/plasticizers, engineering plastic performance improvements/crystallization accelerators, etc. Compounding agents for vehicles, ships, architecture, electric wires, etc. It is used in various fields such as cables, food, packaging, and leisure.

Hereinafter, the present invention will be explained in more detail with reference to examples, but it is clear that widely different embodiments can be constructed without departing from the spirit and scope of the invention.
The invention is not limited to these specific embodiments, except as limited in the accompanying frame.

Example 1 Ethylene-ethyl acrylate polymer (total ethyl acrylate content: 14% by weight, melt index: 9 f/1 (
1 min) 200 F into water 2 in which sodium hydroxide 111 was dissolved/into a pressurized container with an internal capacity of 3.8 t equipped with a magnetic stirrer, nitrogen gas was bubbled from the bottom of the container for 1 hour, After completely eliminating the oxygen dissolved in the water, the air inside the pressurized container was pressurized with nitrogen gas (50 KP/crA) and depressurized (I Kp/c).
nt) operation was repeated five times and the oxygen concentration in the system was measured (Grady method) and found to be less than lppm. The container was then heated to 350 °C for 4 hours in a nitrogen atmosphere.
After the reaction was carried out under the conditions of 200 Ky/ctrl and 200° C., the mixture was cooled in air.

The product has a viscosity average molecular weight of 6,000, and the infrared absorption curve shows that this compound has a molecular weight of 1 mole of acrylic acid and 99 moles of sodium acrylate, based on ethyl acrylate of ethylene-acrylic acid copolymer. It was a compound consisting of

Further, the hue of this product was 1 or less on the Gardner color number.

Example 2 Ethylene-ethyl acrylate polymer (ethyl acrylate content 14% by weight, melt index 9 F/10m
1n>, 200F and 2 g of water in which magnesium acetate 44F was dissolved were placed in a pressurized container with a capacity of 3.8 tons equipped with a magnetic stirrer, and the air inside the container was completely removed with nitrogen gas. After that, the mixture was heated and reacted under the conditions of 350° C. and 200 ν/cA for 4 hours in a nitrogen atmosphere, and then cooled in air.

The product has a viscosity average molecular weight of 6,000, and from the infrared absorption curve, this compound has a ratio of 2 moles of acrylic acid, 1 mole of ethyl acrylate, based on the ethyl acrylate of the ethylene-acrylic acid copolymer. It was a compound consisting of 97 mol% of magnesium acrylate.

Example 3 Ethylene-ethyl acrylate polymer (ethyl acrylate content 14% by weight, melt index 9 F/10m
1n) 200F water with zinc acetate aBy dissolved 2
Equipped with a magnetic stirrer and a capacity of 3.8 tons.
After completely removing the air inside the container with nitrogen gas, it was heated and reacted in a nitrogen atmosphere for 4 hours at 350°C and 200 T'vp/c4. After that, it was air cooled.

The product has a viscosity average molecular weight of 6,000, and the infrared absorption curve shows that this compound contains 2 mol% of acrylic acid, based on the ethyl acrylate of the ethylene-acrylic acid copolymer.
It was a compound consisting of 1 mole of ethyl acrylate and 97 moles of zinc acrylate.

Procedural Amendment Written by the Commissioner of the Patent Office, January 1, 1982, Patent Application No. 170465 of 1982 2. Name of the invention Process for producing modified ethylene copolymer 3. Person making the amendment Relationship to the case Applicant's name (name) ) Japan Petrochemical Co., Ltd. 4, agent address: 11 Minami-Ao, Minato-ku, Tokyo. ．． l-chome 1-1-5,
7. Contents of amendment (1) Specification, page 8, lines 9-10 [..., zinc acetate, etc. are included, and aqueous solutions of these are preferably used. ] should be corrected to "...includes zinc acetate, etc."

that's all

Claims (5)

[Claims] (1) Ethylene-ethyl acrylate copolymer was heated at a temperature of 200°C in the presence of water and metal ions in an inert atmosphere.
A method for producing a modified ethylene copolymer, characterized in that the reaction is carried out under conditions of ~500°C and a pressure of 5 to 500' My/crl. (2) The method for producing a modified ethylene copolymer according to claim 1, wherein the content of ethyl acrylate in the ethylene-ethyl acrylate copolymer is 1 to 40% by weight. (3) The viscosity average molecular weight of the modified ethylene copolymer is 30.
000 or less, the method for producing a modified ethylene copolymer according to claim 1 or 2. (4) The method for producing a modified ethylene copolymer according to any one of claims 1 to 3, wherein the reaction is carried out at an oxygen concentration of 5 ppm or less. (5) The metal ion is an alkali metal ion, an alkaline earth metal ion, Zn-, Sb-1, 02-Fe-2,
Claims 1 to 3 are selected from the group consisting of "Fe+", "Fe+", and mixtures thereof.
4. A method for producing a modified ethylene copolymer according to item 4.