JPS60147412A - Aqueous dispersion - Google Patents

Abstract

PURPOSE:An aqueous dispersion, obtained by adding a copolymer of ethylene and an aminoalkyl acrylate to an acid having a specific dissociation constant, and reacting the copolymer with the acid in combination with an organic acid anhydride, and capable of giving films having improved heat-sealing and antiblocking properties and electric conductivity. CONSTITUTION:A copolymer consisting of (A) 30-80wt% ethylene and (B) 70- 20wt% aminoalkyl acrylate compound expressed by the formula (R1 is H or methyl; R2 and R3 are H or 1-4C alkyl; n is an integer 1-4), e.g. N,N-dimethylaminoethyl methacrylate, is added to at least one or more mineral acids or organic acids having >=10<-5> dissociation constant and reacted therewith in combination of at least one or more organic acid anhydrides, e.g. maleic anhydride, in water to afford the aimed dispersion.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an aqueous dispersion of a reactant made from an ethylene copolymer. This invention relates to an aqueous dispersion of a reactant made from an ethylene copolymer to be formed.゛In general, films or coatings formed from aqueous dispersions made from olefin polymers have excellent transparency, low-temperature heat sealability, water resistance, chemical resistance, and adhesion to various substrates. Therefore, it is widely used as a coating agent and adhesive for paper, plastic, metal, etc.

As one of the aqueous dispersions using an olefin polymer as a raw material, JP-A-47-16542 discloses a copolymer of ethylene and an aminoalkyl acrylate compound as 10-6.
An aqueous dispersion obtained by reaction in water with an acid having a dissociation constant greater than .

It is described that a coating film of a uniform dispersed phase is formed by applying this aqueous dispersion to the surface of a substrate and drying it.

However, coating films formed with the above aqueous dispersion on the surface of substrates such as paper, plastics, and metals have poor heat sealing properties and anti-blocking properties, so there are many problems in practical use9. Improved shortcomings 1't
As a result of extensive research, we found that heat sealing can be achieved by using an aqueous dispersion obtained by reacting a copolymer of ethylene and an alkylamino-acrylate compound in water with a combination of a specific acid and an acid anhydride. The inventors have discovered the fact that the properties and punching resistance are significantly improved, leading to the present invention.

That is, the present invention uses 80 to 80% by weight of ethylene and the general formula (wherein R1 is hydrogen or a methyl group, R2 and R8 are hydrogen or an alkyl group having 1 to 4 carbon atoms, and n is an integer of 1 to 4). , ) Aminoalkyl acrylate compounds 70-
A copolymer consisting of 20% by weight is combined with at least one mineral acid or organic acid having a dissociation constant greater than 10-' and at least one organic acid anhydride. It provides an aqueous dispersion obtained by reacting in water.

The present invention will now be described in detail.

The copolymer with the compound contains 80 to 80% by weight of ethylene, preferably 50 to 75% by weight, and the general formula (wherein R1 is hydrogen or a methyl group, R2 and Rs are hydrogen or a carbon number of 1 to 4.
an alkyl group, n represents an integer of 1 to 4. ) Aminoalkyl represented by acrylate compound 70
~20% by weight, - preferably 50-25% by weight at high temperature,
It is obtained by radical polymerization under high pressure. here,
When the aminoalkyl acrylate compound content is less than 20% by weight, that is, the ethylene content is more than 80% by weight, the aqueous dispersion is poor in hydrophilicity and consists of uniform fine particles even after the reaction with acid and acid anhydride. is not obtained.

Furthermore, if the ethylene content is less than 80% by weight, that is, if the aminoalkyl acrylate compound content exceeds 70% by weight, the hydrophilicity of the reacted acid and acid anhydride will become too large, resulting in poor water resistance of the coating film. However, the problem arises that it lacks blowing resistance, especially under high-temperature conditions. The melting index of the ethylene copolymer is 1 to 50,000 1/10 minutes, preferably 10 to 500, from the viewpoint of the viscosity of the aqueous dispersion and the physical properties, especially the strength, of the dry coating film obtained from the aqueous dispersion.
4F/10 minutes.

The copolymer of ethylene and an aminoalkyl acrylate compound used as a raw material for the aqueous dispersion according to the present invention is disclosed in Japanese Patent Publication No. 42-22528 and Japanese Patent Publication No. 5B-
It can be produced by the high-pressure radical polymerization method described in JP-A No. 6194 and the like. Specific examples of the aminoalkyl acrylate compounds include aminomethyl, acrylate, aminoethyl acrylate, amino normal phthyl acrylate, N-methylaminoethyl acrylate, N-ethylaminoethyl acrylate, N-ethylaminoisobutyl acrylate, N-isopropylaminomethyl acrylate, N-isopropylaminoethyl acrylate, N-normal butylacrylaminoethyl acrylate, N-tert-butylaminoethyl acrylate, N,N-dimethylaminomethyl acrylate, N,N-dimethylaminoethyl acrylate -1,,
N,N-dimethylaminoisopropyl acrylate, N
, N-dimethylamino normal butyl acrylate,
N-methyl-N-ethylaminoethyl acrylate, N
-Methyl-N-n-n-butylaminoethyl acrylate, N,N-diethylaminoethyl acrylate, N,
N-diisopropylaminoethyl acrylate, N,N
- di-normal propylamino normal propyl acrylic
/-)-,N,N-dinormalbutylaminoethyl acrylate, N.

Examples include acrylic acid esters.

Among them, N,N-dimethylaminoethyl acrylate is practically preferred. For the copolymer of ethylene and an aminoalkyl rare acrylate compound, at least one ethylenically unsaturated monomer copolymerizable with other ethylene, such as methyl acrylate, methyl methacrylate,
Ethyl acrylate, n-butyl acrylate vinyl acetate,
It may also be a ternary or multicomponent copolymer made by copolymerizing vinyl propiosinate, acrylic acid, methacrylic acid, etc. within 20% by weight.

Phosphoric acid, vinylic acid, polyphosphoric acid, hydrochloric acid, sulfuric acid, nitric acid, perchloric acid, hydrofluoric acid, hydrobromic acid and In addition to inorganic acids such as hydrometic acid, organic acids such as acetic acid, formic acid, and citric acid can also be used. Particularly preferred are hydrochloric acid, phosphoric acid and sulfuric acid.

Among them, maleic anhydride is particularly preferred.

The total amount of acids and organic acid anhydrides with a dissociation constant greater than 10-5 used in the reaction in the present invention, 2,7
Use□Awa68. 80 to 100 mole parts of amine group in the copolymer with aminoalkyl acrylate compound
It is important that the amount is within the range of 100 mole parts, preferably 40 to 80 mole parts.If the amount used is less than this, the aqueous dispersion will be poor in hydrophilicity and will not be stable.

On the other hand, if the amount used is greater than the above range, the resulting coating film of the aqueous dispersion will be highly hygroscopic and impractical in terms of blocking resistance.

Further, in the present invention, the ratio of the acid and the organic acid anhydride used in the reaction with the ethylene copolymer is in the range of 100 parts by mole to 20 to 200 parts by mole. The effect of improving low-temperature heat sealability and pro-soaking resistance due to the combination with organic acid anhydride is no longer recognized.

The aqueous dispersion of the present invention is prepared by adding a predetermined amount of water, an acid, and an acid anhydride to a copolymer of polyethylene and an aminoalkyl acrylate compound, and heating the mixture at a temperature of 80°C or higher for 0.5 hours or more. It can be easily obtained by stirring.

□Total amount of copolymer, acid, and acid anhydride used during reaction (
The solid content (hereinafter referred to as solid content) is suitably in the range of 5 to 60 parts by weight, preferably 10 to 50 parts by weight, based on 10 parts by weight of water.

If the solid content exceeds 60 parts by weight, the viscosity of the aqueous dispersion becomes high and fluidity is lost, resulting in poor workability when coating paper or the like.

Moreover, if it is less than 5% by weight, not only will the production efficiency of the aqueous dispersion deteriorate, but it will also not be a good idea from the viewpoint of distribution costs and drying energy after coating.

Dyes, pigments, fillers, surfactants, antistatic agents, plasticizers, lubricants, dispersants, antifoaming agents, and aqueous resins such as polyvinyl alcohol may be added to the aqueous dispersion of the present invention as necessary. is also possible.

The aqueous dispersion of the present invention forms a film with good transparency by heating and drying. The resulting film has excellent low-temperature heat-sealing properties, blocking resistance, water resistance, chemical resistance, adhesion to various substrates, and electrical conductivity. Pigment binders for paper processing, heat-sealable papers, adhesives for multilayer laminated papers, low-temperature heat-sealable polypropylene films, metal surface treatment agents, textile binders, water-based inks, adhesives for plastic coatings on metals, paper and plastic coatings. Obi 1? ! It can be used in a variety of ways, including providing preventive properties.

Hereinafter, the present invention will be explained with reference to Examples, but the present invention is not limited thereto.
, a pellet-like copolymer of ethylene and N,N-dimethylaminoethyl methacrylate with an M ratio of 64:86 (
MeltInde Sox 300, JIS K-6760 compliant M100F, maleic anhydride 14N and 85% phosphoric acid 24f (equivalent to 20 mol parts of maleic anhydride and 80 mol parts of phosphoric acid per 100 mol parts of the amine group of the copolymer) ) was charged, the temperature was raised from room temperature to 100°C in a stirring tray, and the reaction was completed by stirring at reflux F for 60 minutes at 100°C.

Subsequently, the mixture was cooled to 50° C. with stirring, and then filtered through a 200-meter stainless steel wire mesh.

The resulting reaction product was a pale yellow, uniform aqueous dispersion, and the particle size of the dispersion was 0.1 jcrom or less. Also, the pH is 5.
2, and the particle size was 17 cp (25°C). In addition,
The solid content obtained by heating the reaction product to 100°C to evaporate water was 20% (weight ratio).

This aqueous dispersion was coated on the surface of high-quality paper (84 g/m2) using a #10 bar coater, and dried in a hot air circulation dryer for 15 minutes at 100"C to reduce the coating solid content to 6.
．． 0117 m2 of coated paper was obtained.

The coated surfaces of this coated paper are overlapped to form a thermally inclined shape e-),
-11z f X + -1cr r, 80"C185"
C'? 1 Heat sealing was performed at a temperature of 90°C at IKf/d for 1 second, and T-peeling was performed at a speed of 200 μ/min using an autograph. As shown in Table 1, the results were 50. 400fl / 2.5 cm width and
4501/c! It showed good adhesion of i or more (paper breakage).

Next, use the above-mentioned paper, overlap the coated surfaces, and
After applying a load at 12°C, 12Kip/crA for 2 hours, a peel test was conducted, but almost no blocking was observed.

In addition, the surface electrical resistance of the coated paper surface was measured using a super insulation meter (SM-10E) made by Toa Denpa at an applied voltage of 100 v and a humidity of 60.
When measured at a %RH1 temperature of 25°C, it was found to be 9xlOΩ. On the other hand, the surface electrical resistance of the paper before coating is 5X10
The resistance was 18Ω, and the coating provided a remarkable antistatic function.

Examples 2 to 6 Using a method similar to that described in Example 1, 1) the composition and melt index of the ethylene copolymer as a raw material, 2) the type of acid and acid anhydride, and 8) the ethylene copolymer. Table 1 summarizes the results of experiments conducted by changing factors such as the reaction ratio of acid and acid anhydride to amino groups in the polymer, and 4) solid content concentration.
Shown below.

Comparative Examples 1 to 6 For the purpose of comparison with the above examples, 1) When an acid or acid anhydride is used alone 2) Reaction ratio of acid and acid anhydride to amino groups in ethylene copolymer 8) Ethylene Composition of copolymer 4) Table 1 summarizes experimental examples conducted under conditions other than the range described in the patent specification for factors such as solid content concentration.

From the results shown in Table 1, the effect of combining acid anhydride in addition to acid is clear from both the heat sealability and blocking resistance.

Claims (1)

[Claims] '(11' 80 to 80% by weight of ethylene and the general formula (wherein Rt is hydrogen or a methyl group, R2 and Rs are hydrogen or an alkyl group having 1 to 4 carbon atoms, and n is 1 to 4 alkyl groups) Aminoalkyl acrylate compounds 70-
At least 1 ethylene copolymer consisting of 20% by weight
An aqueous dispersion obtained by reacting in water a combination of a mineral acid or an organic acid having a dissociation constant of more than 10@-5 and at least one organic acid anhydride. (2) The aminoalkyl acrylate compound is N. The aqueous dispersion according to claim 1, which is N-dimethylaminoethyl methacrylate. (8) The aqueous dispersion according to claim 2, wherein the organic acid anhydride is maleic anhydride. (4) The aqueous dispersion according to claim 8, wherein the mineral acid or organic acid having a dissociation constant greater than 10' is phosphoric acid.