JPS61148278A - Aqueous suspension of adhesive microsphere - Google Patents

Abstract

PURPOSE:To provide the titled adhesive suspension compound of microspheres consisting of an internally crosslinked copolymer obtained by the copolymerization of a methacrylate and maleic anhydride, etc., water, and a suspension stabilizer, having excellent shape retainability of the sphere and readhesivity. CONSTITUTION:The objective suspension is composed of (A) microspheres having particle diameter of 5-200mu and consisting of an internally crosslinked copolymer obtained by the copolymerization of (a) 1-10(wt)% alcohol acrylate and/or 1-5C alcohol methacrylate and/or styrene, (b) 98-90% 2-12C alcohol acrylate and/or 6-12C alcohol methacrylate, (c) 0.1-2.0% maleic anhydride and (d) 0.05-1.0% one or more components selected from tetraallyloxyethane, triallyl cyanurate, and triallyl isocyanurate, (B) water and (C) a suspension stabilizer.

Description

[Detailed Description of the Invention] More specifically, it relates to an aqueous suspension of sticky microspheres that has a narrow particle size distribution of microspheres in the suspension and is difficult to swell with solvents. It is.

In recent years, adhesive resin microspheres are lined up and adhered to the surface of paper,
Office supplies that can repeat the process of pasting the paper microspheres on another surface, then peeling it off, pasting it again, and peeling it off again have been slow to become available. There is.

This utilizes the characteristics of sticky resin microspheres with particle diameters ranging from several microns to several hundred microns.

That is, since the spherical adhesive resin is lined up on the surface of the paper like the suction cups of an octopus, when another surface comes into contact with that surface, adhesion occurs at countless points and both surfaces are bonded. Then, when both sides are peeled off, the adhesive resin microspheres are exposed as they are because they are peeled off from the point-adhesive area, and can be reattached to the adherend. Such repeatedly removable paper is obtained by applying a suspension of sticky resin microspheres to the paper.

However, when a solvent solution or aqueous emulsion of an adhesive resin is applied to paper, an adhesive film is formed on the surface of the paper, and when the paper is attached to an adherend, surface adhesion occurs, so when the paper is peeled off, It does not peel off at the interface, causing delamination between the paper layers and making it impossible to stick it again.

In addition, even if a suspension is applied, if the particle size reaches 1000 microns (11III), the number of contact points per unit area will decrease, resulting in weaker adhesive strength and the adhesive area will become thicker, making it practical. Not on point.

Therefore, it is preferable that fine spheres having an average particle diameter of several microns to several hundred microns are closely arranged on the surface of the paper.

Further, it is preferable that the shape of the fine spheres be as true as possible.

If it is crushed like a rough ball, it becomes close to surface adhesion, and the adhesive strength becomes strong, causing paper layer peeling (paper peeling).

Further, it is preferable that the particle size distribution be as narrow as possible. Because only large particles selectively participate in adhesion,
This is because the adhesive strength is weak and it is not practical.

By the way, this type of sticky resin microspheres that have been known in the past are manufactured by suspension polymerizing acrylic monomers in water using an oil-soluble polymerization initiator. There is no problem when applying an aqueous suspension of microspheres to a non-water-absorbing substrate, but when applied directly to paper, the paper curls due to moisture, significantly reducing its commercial value.
Usually, water, which is the solvent of an aqueous suspension, is replaced with a solvent such as toluene, ethyl acetate, or 1,1.1-trichloroethane, and the suspension is applied to paper as a solvent-based suspension. On top of that,
Using a solvent system has the advantage that it has a faster drying rate than a water system and has extremely good mechanical stability.

However, with conventionally used resins, even if a poor solvent with low affinity is selected, the resin tends to swell to a greater or lesser degree, and sticky microspheres fuse together to form a film. Therefore, surface adhesion occurs with other adhered surfaces, and when peeled off, the paper layer peels, resulting in poor re-adhesion.

The present inventor has considered internally crosslinking the adhesive resin for the purpose of making it difficult to swell in solvents and imparting appropriate adhesive performance.

That is, when carrying out the polymerization reaction, an attempt was made to add an appropriate amount of a monomer having two polymerizable functional groups to carry out the polymerization.

Polymerization was performed using divinylbenzene, butanediol diacrylate, ethylene dimethacrylate, and diacetone acrylamide as crosslinking monomers, but all of them had poor reactivity and did not crosslink uniformly, so when substituted with a solvent. Swelling and dissolution occurred in some areas, and when applied to paper, it flowed and formed a film, with surface adhesion everywhere.

If the amount of crosslinkable monomer used is increased in order to minimize solvent swelling, the tackiness will decrease and the tackiness will become insufficient.

The present inventor conducted further studies and polymerized with different types of internal crosslinking monomers, and found that tetraallyloxyethane, triallyl cyanurate, and triallyl isocyanurate had extremely high reactivity. Because of the uniform internal cross-linking, we have discovered that the aqueous suspension of perfectly spherical fine spheres with uniform particles does not swell or dissolve even when the water in the suspension medium is replaced with a solvent. completed.

That is, the present invention provides (a) acrylate of alcohol having 1 carbon number and/or methafrylate of alcohol having 1 to 5 carbon atoms and/or 2 to 10% by weight of styrene (b) acrylate of alcohol having 2 to 12 carbon atoms and/or or methacrylate of alcohol having 6 to 12 carbon atoms 98 to 90% (C1 maleic anhydride)
0.1 to 2.0% by weight (0.05 to 1.0% by weight of one or more selected from small tetraallyloxyethane, triallyl cyanurate, and triallyl isocyanurate) This is an aqueous suspension of sticky microspheres made of a crosslinked copolymer with a particle size of 5 to 200 microns, water, and a suspension stabilizer.

The acrylate of alcohol with 1 carbon number used in the present invention (a1) is methyl acrylate, and the homopolymer glass transition temperature (■0) of this is 8°C.
It is.

Methacrylates of alcohols having 1 to 5 carbon atoms include methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, and pentyl methacrylate.
II is 105°C, 66°C, 35°C, and 21°C, respectively.
, 10°C.

Further, 10 of the styrene homopolymer is 100°C.

That is, (all of the 11 bodies shown in section a1 have a homopolymer (■0) of 0°C or higher and around 100°C.

In addition, the acrylate of an alcohol with 2 to 12 carbon atoms and/or the methacrylate of an alcohol with 6 to 12 carbon atoms shown in the term ethyl acrylate (T(1=-
22°C), butyl acrylate (T(] = -52°C),
2-Ethylhexyl acrylate (T(] = 70℃)
, hexyl methacrylate (■ = -5°C), etc., are the monomers shown in the (mounted) section all with -0 of the homopolymer less than 0°C? 4. 2 shows the number 10 degrees and 1 also has 1. This is to essentially impart adhesive properties to the resin.A sticky resin cannot be obtained outside this range.

Maleic anhydride in item (0) is used in an amount of 0.1 to 2.0% by weight, which allows the polymerization reaction to proceed smoothly.
This is to create a stable suspension.

(Tetraallyloxyethane at the summit is It is shown by the structural formula, triallyl cyanurate is It is shown by the structural formula, triallyl isocyanurate is It is shown by the structural formula:

Compared to ordinary internal crosslinking agents, it has 3 to 4 polymerizable functional groups.
It is believed that the reactivity is extremely high because of the proprietary nature of the compound, which results in uniform internal crosslinking.

These may be used alone or in combination.

The amount used is suitably 0.05 to 1.0% by weight.

If it is less than 0.05% by weight, the internal crosslinking effect is small, so
Solvent resistance is insufficient, and if it exceeds 1.0% by weight, crosslinking progresses too much and adhesive performance deteriorates, which is not preferable.

In the present invention, 10% by weight of other monomers such as N-methylolacrylamide, acrylonitrile, ethylene, vinyl chloride, vinyl acetate, Beoba (trade name of vinyl ester manufactured by Shell Chemical Co., Ltd.) in an amount that does not impair adhesive performance is used.
Can be used together within the following range.

As a method for producing the aqueous suspension of sticky microspheres of the present invention, a known suspension polymerization method is used.

Examples include a polymerization method by bulk feeding, a monomer dropwise polymerization method, and an emulsified monomer dropwise polymerization method.

As a polymerization initiator, benzoyl peroxide, azobisisobutyronitrile, tert-butyl perbenzoate,
Cumene hydroperoxide, diisopropyl peroxydicarbonate, di-n-propyl peroxydicarbonate, di(2-ethoxyethyl) peroxydicarbonate, tert-butylperoxyneodecanoate, tert-butylperoxypivalate, Ji (3,
Oil-soluble initiators such as 5,5-trimethylhexanoyl peroxide, dilauroyl peroxide, diprobionyl peroxide, diacetyl peroxide, etc. are used.

As the suspension stabilizer, water-soluble polymers such as polyvinyl alcohol, hydroxyethylcellulose, sodium polyacrylate, polyvinylpyrrolidone, levoxymethylcellulose, and carboxy-modified polyacrylamide are used.

Moreover, an anionic surfactant and a nonionic surfactant can be used in combination. In particular, in order to stably produce a suspension, it is preferable to use a large amount of anionic surfactant.

The particle diameter of the microspheres is suitably within the range of 5 microns to 200 microns.

Therefore, the width of the particle size distribution that includes 80% of the microspheres is about 10 microns when the average particle diameter is around 5 microns, and 2.
In the vicinity of 0.00 microns, a thickness of approximately 30 microns is preferable.

In the adhesive microsphere aqueous suspension of the present invention, since the microspheres are internally cross-linked, they have an extremely good ability to retain their spherical shape, and when used as an adhesive, contact with objects to be adhered is prevented. Since it is maintained by point adhesion of the spheres, readhesion is extremely good. This effect is effectively achieved both when water is replaced with an organic solvent and when the aqueous dispersion is used as it is. Of course, as mentioned above, the problem of swelling, which could not be solved in the past when replacing water with an organic solvent, has been completely solved.

Next, the present invention will be explained with reference to Examples and Comparative Examples.

Example 1 Methyl methacrylate 20 parts by weight (4,7χ)
2-ethylhexylac 400 n (94,
1%) rylatetetraallyloxyethane 1.0 # (0,24
%) Maleic anhydride 4.0, (0,
Adhesive microsphere aqueous suspension consisting of microspheres of which 80% have a particle size of 80 to 100 microns, water, and a suspension stabilizer. .

This product was manufactured as follows.

(Ingredients) (Parts by weight) Methyl methacrylate 202-ethylhexyl acrylate 400 Tetraallyloxyethane 1.0 Maleic anhydride
4.0 Sodium polyacrylate
16 (Polymerization [3000-7000) Water
600 benzoyl peroxide
2.0 Sodium Dodecylbenzenesulfonate A polymerization reaction is carried out using 20 or more components, and 80% have a particle size of 80.
An aqueous suspension of ˜100 micron sticky corpuscles was obtained.

Example 2 Styrene 12 parts by weight (2.9%)
Butyl acrylate 390 N (95,
6%) triallyl isocyanate 1.0 # (
0,25%) nurate maleic anhydride 5 II (1,2
A sticky microsphere aqueous suspension consisting of microspheres, 80% of which have a particle size of 15 to 50 microns, water, and a suspension stabilizer.

This product was manufactured as follows.

(Ingredients) (Parts by weight) Styrene 12-butyl acrylate 390-trialyl isocyanurate 1,0-maleic anhydride
5 hydroxyethyl cellulose 20 water
600 benzoyl peroxide 2
．． 0 Sodium dodecylbenzenesulfonate A polymerization reaction is carried out using 20 or more components, and 80% have a particle size of 15~
An aqueous suspension of 50 micron sticky microspheres was obtained.

Example 3 Methyl methacrylate 32 parts by weight (7.3%)
Isononyl acrylate 400 # (91,5
%) triallyl cyanurate 3.7 # (0
, 85%) maleic anhydride 15 II
Adhesive microspheres aqueous, consisting of internally crosslinked copolymer obtained by copolymerizing (0.34%), 80% of which are microspheres with a particle size of 45 to 70 microns, water, and a suspension stabilizer. suspension.

This product was manufactured as follows.

(Ingredients) (Parts by weight) Methyl methacrylate 32 Isononyl acrylate 400 Triallyl cyanurate
3.7 Maleic anhydride N1.5 Polyvinyl alcohol 15 Water
60
0 benzoyl peroxide 2.0 sodium dodecylbenzenesulfonate A polymerization reaction was carried out using more than 20 components to obtain an aqueous suspension of sticky microspheres, 80% of which had a particle size of 45 to 70 microns.

Example 4 Methyl methacrylate 32 parts by weight (7.3%)
15-1 isononyl acrylate 400 II (91
, 8%) tetraallyloxyethane 2,, (
0.46χ) Anhydrous Malein Fill 1.
Adhesive fine particles consisting of internally crosslinked copolymer obtained by copolymerizing 5n (0.34%), 80% of which are microspheres with a particle size of 35 to 60 microns, water, and a suspension stabilizer. Globular aqueous suspension.

This product was manufactured as follows.

(Ingredients) (Parts by weight) Methyl methacrylate 32 Isononyl acrylate 400 Tetraallyloxyethane
2 Fomaleic acid anhydride
1.5 Polyvinylal]-ru 15 Water

600 benzoyl peroxide 2.
0 Sodium dodecylbenzenesulfonate A polymerization reaction is carried out using 20 or more components, and 80% have a particle size of 35 to 6.
An aqueous suspension of 0 micron sticky microspheres was obtained.

Comparative Example 1 An aqueous suspension of sticky microspheres of which 80% had a particle size of 80 to 100 microns, which was obtained by copolymerizing in Example 1 without using tetraallyloxyethane.

The manufacturing method was based on Example 1.

Comparative Example 2 In Example 1, tetraallyloxyethane was added to 6,5
80% by weight (1.5% by weight based on total monomers) consisting of internally crosslinked monomers obtained by copolymerization
is an aqueous suspension of microspheres with a particle size of 80 to 100 microns.

The manufacturing method was based on Example 1.

Comparative Example 3 In Example 2, 1 hearylylisocyanurate 1
．． An aqueous suspension of 80% microspheres with a particle size of 15 to 50 microns, consisting of an internally crosslinked copolymer copolymerized with 2.0 parts by weight of divinylbenzene instead of 0 parts by weight.

The manufacturing method was the same as in Example 2.

Comparative Example 4 An 80% internally crosslinked copolymer obtained by copolymerizing Example 3 by changing triallyl and cyanurate to 6 parts by weight (1.4% by weight based on the total monomers). is an aqueous suspension of microspheres with a particle size of 45 to 70 microns.

The manufacturing method was based on Example 3.

Comparative Example 5 In the production of Example 4, polymerization was carried out in the same manner as in Example 4, except that maleic anhydride was not used. However, a lot of aggregates were formed during the reaction and the target product could not be obtained. .

Comparative Test 1 The aqueous suspensions obtained in Examples 1 to 4 and Comparative Examples 1 to 4 were added to methanol to coagulate, and after washing, the lumpy resin was taken out and reconstituted in various organic solvents shown in Table 1. The degree of swelling of the particles was examined by dispersing the particles in a solvent-based suspension at a temperature of about 25%.

The results were as shown in Table 1.

(Test method) Degree of swelling of particles (rate of change) The above solvent-based suspension was applied to a polyester film with a thickness of 38 microns at approximately 30Q/m', and immediately after application and at room temperature 3
The rate of change in particle diameter after 0 minutes was determined and was taken as the swelling degree of the particles.

However, the particle size was measured using a microscopic photograph.

Comparative Test 2 Cohonyl 4 was used as an undercoat on high-quality paper (55K).
081 (a 50% methanol solution of acrylic/vinyl acetate copolymer 8I resin manufactured by Nippon Gosei Chemical Industry Co., Ltd.) was added to about 1.5 oz.
/vl coating and drying, then apply the solvent-based suspension prepared in Comparative Test 1 on top of it with a solid content of approximately 7.50/vl, and heat at 40°C.
A pressure-sensitive adhesive sheet was prepared by drying with hot air for 30 minutes, and the number of times of repeated contact/peeling was examined.

The results were as shown in Table 1.

(Test method) Number of times of repeated contact/peeling Adhesion/peeling was repeated on the printed newspaper surface, and the number of times until no longer adhesion was determined was determined.

We also checked for peeling of the print (paper tearing phenomenon).

[Margin below]

Procedure Nefu Seisho (self-motivated) February 5, 1985

Claims (1)

[Scope of Claims] 1(a) Acrylate of alcohol having 1 carbon number and/or methacrylate of alcohol having 1 to 5 carbon atoms and/or styrene 2 to 10% by weight (b) Acrylate of alcohol having 2 to 12 carbon atoms and/or methacrylate of alcohol having 6 to 12 carbon atoms 98 to 90% by weight (C) maleic anhydride 0.1 to 2.0% by weight (d) from tetraallyloxyethane, triallyl cyanurate, triallyl isocyanurate Microspheres with a particle diameter of 5 to 200 microns made of an internally crosslinked copolymer obtained by copolymerizing 0.05 to 1.0% by weight of one or more selected species, water, and a suspension stabilizer. An aqueous suspension of sticky microspheres.