JPS62141046A - Aqueous dispersion of ethylene copolymer - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD The present invention relates to aqueous ethylene copolymer dispersions.

According to the present invention, there is provided an ethylene copolymer water-land dispersion that can be used in a wide range of applications such as adhesives and paints, and is particularly easy to work with in that it has a low viscosity even at high resin concentrations. can do.

Prior Art Water-dispersible ethylene copolymers containing ethylene and α,β-unsaturated carboxylic acids are disclosed in JP-A-52-109545;
53-59789, etc., when applying a permanent dispersion of these copolymers to a legal material, it is necessary that the viscosity of the aquatic dispersion be within an appropriate range in order to ensure proper application. It is said to be desirable.

In general, increasing the concentration of ff and I fat in the aqueous dispersion will result in a thick coating film of 1 tsubo, and is also preferable from the point of view of energy conservation, but if the resin concentration is high, the viscosity of the water-1'lE separation liquid will be extremely high. It is said that it will increase.

As a method to improve this point, for example, Japanese Patent Application Laid-Open No. 55-843
Although a method as disclosed in Publication No. 28 has been proposed,
In such a method, it is necessary to inject a gas, and there has been a need for a method that more easily solves the above problems.

Summary of the Invention The present invention provides an ethylene copolymer aqueous dispersion in which an ethylene copolymer containing ethylene and α,β-unionized carboxylic acid is dispersed in water using chlorine. The Q value (weight average molecular weight/number average molecular weight) of the polymer is in the range of 2.0 to 3.0, and the crystallization temperature and melting point are expressed by the following formula: 35
℃≦(1Kiyaku humidity) is 2 X (melting temperature) -40℃
and (melting temperature) of 690°C.

Effects of the Invention The ethylene coplanar aqueous dispersion (of the present invention) has a low viscosity over a wide 1 degree range, and has a high resin, 1 degree
Even if a water-to-water dispersion with a certain degree is used, workability is excellent and a good @ membrane can be obtained.

By using an ethylene copolymer whose Q value range, crystallization temperature, and degree of decomposition are specified by the formula of the above-mentioned ethylene copolymer, the above-mentioned excellent Koto can be obtained. )
What happened was completely unexpected.

``Jjiguri 9 (1) The ethylene copolymer used in the present invention is composed of ethylene, α, β
-, β-carboxylic acid.

Specific examples of α, β-, and β-carboxylic acids include monobasic acids such as acrylic acid, methacrylic acid, and crotonic acid, and dibasic acids such as fumaric acid, maleic acid, and itaconic acid. Among these, acrylic acid and methacrylic acid are preferred.

The ethylene copolymer used in the present invention includes, in addition to ethylene and the above-mentioned α,β-fufuwa carboxylic acid, a monomer copolymerizable with these monomers, such as α.

Even if it is a copolymer of one or more third monomers such as β-unsaturated carboxylic acid ester, α,β-unsaturated amide, α,β-unsaturated nitrile, carboxylic acid vinyl ester, etc. good.

The above ethylene copolymer used in the present invention has a composition of 97 to 85 mol% ethylene, 15 mol% α, β-unsaturated unsaturated carboxylic acid, and 0 to 10 mol% third monomer as necessary. preferably 95 to 85 mol% of ethylene and 5 to 85 mol% of α, β-, β-carboxylic acid.
15 mol %, and the third monomer is 0 to 5 mol %.

The copolymer used in the present invention is produced by subjecting predetermined monomers to copolymerization conditions, and can be produced using a high-pressure polyethylene production apparatus.

The co-It aggregate is produced by combining the radical jl.

Therefore, the catalyst used in the production of the copolymer used in the present invention is a compound that generates free radicals.

For example, dialkyl peroxides such as ditertiary butyl peroxide, tertiary butylcumyl peroxide, and dicumyl peroxide; diacyl peroxides such as acetyl peroxide, inbutyl peroxide, and octanoyl peroxide; peroxydicarbonates such as carpocarbonate, di-2-ethylhexyl peroxydicarbonate,
Peroxy esters such as tertiary butyl peroxyinopterate, tertiary butyl peroxy pivalate, tertiary butyl peroxy laurate, tertiary butyl peroxy neodecanoate, ketones such as methyl ethyl ketone peroxide, cyclohexanone peroxide, etc. Peroxide, peroxyketal such as 1,1 bistarciabutyl peroxycyclohexane, 2.2 bistarhyabutylperoxyoctane, hydroperoxide such as tertiary butyl hydroperoxide, cumene hydroperoxide, 2.2 Azo compounds such as azobisisobutyronitrile.

This polymerization is preferably carried out in a continuous manner. 1 Co. Ltd. can use a continuous stirring type continuous stirring type reactor or a continuous tubular type reactor which is generally used in high pressure radical polymerization of ethylene.

The polymerization can be carried out as a single-zone process using these single reactors, but many reactors can be used in series, possibly with connected condensers, or several internal sections can be used to create a multi-zone process. A single reactor can also be used, effectively divided into zones. In a multi-zone process, one main unit is used for each reactor or reaction zone, so that the reaction conditions in each zone are varied to control the properties of the polymer obtained in each reactor or reaction zone. It is common to adjust the composition, catalyst concentration, degree of molecular weight regulator, etc. When multiple reactors are connected in series, in addition to the combination of two or more seed reactors or two or more tube reactors, one or more seed reactors and one or more tube reactors are used. Combinations with type reactors can also be used.

The polymer produced in the reactor or reactors can be separated from unreacted units and processed as in the production of conventional high pressure polyethylene. The mixture of unreacted monomers is mixed with an additional amount of the same monomers,
Repressurize and circulate to the reactor. The additional amount of monomer added as described above is of a composition that returns the composition of the mixture to that of the original feed, and generally this additional amount of monomer is added to the polymer separated from the polymerization vessel. It has a composition roughly equivalent to that of the coalescence.

In addition, the reactor is preferably a seed type reactor in order to obtain a copolymer with a uniform composition.

The catalyst is usually dissolved in a solvent with a small chain transfer effect and directly injected into the reactor using a high pressure pump. ) degree is 0.5 ~
About 30% by weight is desirable.

Suitable solvents include, for example, hexane, heptane, white spirit, hydrocarbon oils, cyclohexane, toluene, higher branched chain saturated fatty acid hydrocarbons, and mixtures of these liquids.

Further, the α,β-unsaturated carboxylic acid is supplied as it is or dissolved in a solvent using a high-pressure pump.

In high-pressure radical polymerization, a chain transfer agent is generally used to adjust the molecular weight, except in special cases.

As the chain transfer agent, all those used in ordinary high-pressure radical polymerization can be used.

For example, alkanes such as ethane, propane, butane, hexane, heptane, alkenes such as propylene, butene, hexene, alcohols such as ethanol, methanol, propatool, ketones such as acetone, methyl ethyl ketone, acetaldehyde, propionaldehyde, etc. Aldehydes such as methyl acetate, esters such as ethyl acetate, and many other compounds used in high-pressure methods can be used.

These gaseous substances are injected into the suction side of the compressor, and the liquid substances are injected into the reaction system by a pump.

The polymerization pressure employed is in excess of 1 kg/d, preferably in the range of 300 kg/ctd to 300 kg/ctd.

The polymerization temperature is preferably at least 120°C.
It is in the range of 0 to 300°C.

The copolymer used in the present invention produced in the reactor is separated from the monomer in a separator according to a conventional high-pressure radical method, and becomes a product as it is.

This product may be used as it is, or may be subjected to various post-treatment steps such as those already used for products obtained by high-pressure radical polymerization.

The Q value (weight average molecular weight/number average molecular weight) of the ethylene copolymer thus produced is in the range of 2.0 to 3.01, preferably 2.0 to 2.7, more preferably 2.0 to 2.5. and its crystallization temperature and melting temperature are the following formula, 35℃≦(crystallization temperature) is 2X (melting temperature I history) - 400
and (M melting temperature) in the range shown by 690°C, preferably according to the following formula, 40°C≦(crystallization temperature) in the range shown by 2X (melting temperature) -40C and (melting temperature)≦85°C Ethylene copolymers must be used in this invention.

Here, the Q value is measured by a known method using gel permeation chromatography (GPC) and differential refractometer, based on a calibration curve using standard (monodisperse) polystyrene. I found the sewing and calculated it from this. The conditions for this GPC measurement are as follows.

Column: Polystyrene gel column (7 combination type), 8+m
'X250 x 3 bottles 8 soot: 1.2.4-) IJ dichlorunzene: Vinegar m
= 9:1 (volume ratio) Flow rate = 1-7 minutes Temperature = 80℃ Injection amount = 300μt Group 1 change: 3η/d Detector: Differential refractometer Also, measurement of crystallization temperature and melting temperature (d1 differential scanning thermal It was determined by a known method using DSC.
This DSC1all constant condition is Du Pont's Mode? Using DSCZ, sample amount is approximately 5!1L
It was carried out under a nitrogen atmosphere at a ramp rate of 110° C./min or a temperature rate of 4.

A water-based dispersion solution is produced by combining the ethylene and ethylene obtained as described above, and methods for producing an aqueous dispersion are described, for example, in JP-A-49-120789 and JP-A-52-109.
The methods for solubilizing carboxyl group-containing polymers described in Publications No. 545 and No. 56-120780 are employed.

A preferred method for preparing the raw ethylene copolymer dispersion in water of the present invention is to add water and a base to the ethylene copolymer, and heat the copolymer to a temperature of 200° C. to melt the copolymer without stirring. This is a method of obtaining an aqueous dispersion. Here, in terms of preventing corrosion of the equipment by base, the melting temperature of the copolymer ~
It is more preferable to manufacture by heating to a range of 120°C.

The base used to prepare the aqueous dispersion of the invention is:
From a practical standpoint, alkalies such as lithium hydroxide, sodium hydroxide, and potassium hydroxide may be used, but are not particularly limited as long as they can neutralize carboxylic acids and do not impede the stability of the aqueous dispersion. Preferred are metal hydroxides, organic amines such as methylamine, triethylamine, ethylenediamine, and monoethanolamine, and ammonia.

The amount of base used is approximately equal to 2 of the acid groups contained in the copolymer.
The amount neutralizes 0 mol% or more, preferably 40 to 90 mol%. Generally, the smaller the amount of base used, the lower the viscosity, but if the amount of base used is less than 20 mol %, it becomes difficult to produce a stable aqueous dispersion.

If the concentration of the ethylene copolymer of the present invention in the aqueous dispersion is too low, the thickness of the coated film will be limited and the amount of water blown away will be large, which is unfavorable from the point of view of energy saving; If it is too high, the viscosity of the dispersion becomes high and the workability during coating becomes poor, so it is generally preferable that the content is 15 to 50% by weight.

The aqueous dispersion of the present invention has four characteristics in that the ethylene copolymer is neutralized with a base and dispersed in water. (For example, see JP-A-57-137337, etc.)
Additives such as surfactants, plasticizers, preservatives, antifoaming agents, thickeners, antistatic agents, lubricants, ultraviolet absorbers, anti-blocking agents, etc., as well as methanol for the purpose of accelerating drying. , lower alcohols such as ethanol and ingropanol, ethylene glycol, ethyl ether or butyl ether of ethylene glycol for the purpose of improving film-forming properties, and water-based alcohols of the present invention for the purpose of reducing costs, controlling blocking resistance or adhesion, etc. Known aqueous dispersions of polyethylene, polyvinyl acetate, polyvinyl chloride, ethylene-vinyl acetate copolymers, polyvinylidene chloride, polyacrylic acid, and the like which are compatible with the dispersion can also be blended.

Experimental Examples Reference Example 1 (Production of ethylene copolymer) Ethylene, acrylic acid, a polymerization initiator, and a chain transfer agent were continuously supplied using a tank reactor equipped with an agitator, and the polymerization pressure was 1,80.0~.
Polymerization was carried out at a polymerization temperature of 2,500 to 2,500° C. and a polymerization temperature of 190 to 230° C. to obtain the ethylene-acrylic acid copolymer shown in Table 1. Table 1 shows the physical properties of the obtained copolymer.

Table 1 also shows the physical properties of commercially available ethylene acrylic acid copolymers.

(Leaving space below) Table 1 Example 1 125? 25% ammonia water 17.29
An aqueous dispersion was prepared by adding 357.8 f of distilled water and stirring at IOOO°C for 2 hours.

After leaving the obtained aqueous dispersion at room temperature for one week, its viscosity was measured using a B-type viscometer at 230°C and rotor rotation speed 20.
When measured by rpM, it showed 40 centivoise.

Examples 2 to 7, Comparative Examples 1 to 4 Aqueous dispersions were produced in the same manner as in Example 1, except that the type and amount of the ethylene copolymer used and the amount of 25% ammonia water were changed, The viscosity was measured after it was left at room temperature for one week. The results are shown in Table-2.

From the results in Table 2, the aqueous fraction of the present invention has a low viscosity over a wide concentration range, and is an aqueous dispersion that has a particularly low viscosity at the dissolved resin concentration of iH fat a of 25 wt. That is clear.

(Margin below) Table-2

Claims (1)

[Claims] (1) In an ethylene copolymer aqueous dispersion in which an ethylene copolymer containing ethylene and an α,β-unsaturated carboxylic acid is dispersed in water using a base, the Q value (weight average molecular weight/number average molecular weight) is 2.0
~3.0, and its crystallization temperature and melting temperature are expressed by the following formula: 35°C≦(crystallization temperature)≦1.2×(melting temperature)-40
An aqueous dispersion of an ethylene copolymer, characterized in that the dispersion is in the range shown by: °C and (melting temperature)≦90 °C.