JPH0667967B2 - Method for producing stable dispersions of vinyl polymers - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing a stable dispersion of a vinyl polymer, and more specifically, perfluoro having a significantly low intermolecular cohesive force, is chemically stable, and has a very low surface tension. Using a polymer of an alkyl group-containing (meth) acrylic monomer as a dispersion stabilizer, at least one radically polymerizable monomer is polymerized in an organic liquid in the presence of the resin to obtain the organic compound. It relates to a method for producing a stable dispersion of liquid-insoluble polymer particles.

A homopolymer resin of a perfluoroalkyl group-containing (meth) acrylic monomer [hereinafter, sometimes abbreviated as monomer (I)] or a copolymer containing the monomer (I) as a copolymerization component. The united resin exhibits water repellency, oil repellency, stain resistance, non-adhesiveness, and has a low refractive index.

The homopolymer resin of the monomer (I) or the copolymer resin containing the monomer (1) as a copolymerization component having such practically excellent properties can be prepared by a conventional solution polymerization method. It is synthesized.

When a copolymer resin containing the monomer (I) as a copolymerization component is synthesized by the solution polymerization method based on such conventional methods, perfluorocarbons such as water repellency, oil repellency, stain resistance and non-adhesiveness are obtained. In order to fully exhibit the characteristics of the alkyl group, it is necessary to copolymerize a certain amount or more of the monomer (1).
In this case, in order to copolymerize a certain amount or more of the monomer (1) as a copolymerization component, it is necessary to prepare as a coating film other than the characteristics based on the perfluoroalkyl group, which causes a decrease in mechanical properties. There are cases. That is, in many cases, it is difficult to simultaneously exhibit the properties inherently possessed by the coating film and the properties based on the perfluoroalkyl group. Further, the monomer (I) having a perfluoroalkyl group is extremely expensive as compared with a general polymerizable vinyl-based monomer, and it is indispensable to exert its effect with a necessary minimum amount of copolymerization. Becomes

As a result of diligent efforts to solve the technical and economic problems as described above, we have recently used non-aqueous polymer dispersions (hereinafter referred to as (Hereinafter abbreviated as "NAD") as a dispersion stabilizer of a monomer (I) homopolymer resin or monomer (I)
It was found that the above problems can be solved by using a copolymer resin containing as a copolymerization component, and the present invention has been completed.

Thus, according to the invention, the following general formula (In the formula, R represents a hydrogen atom or a methyl group, and n is 1 to
Hf represents an integer of 10 and Rf represents a linear or branched perfluoroalkyl group having 3 to 21 carbon atoms.) A homopolymer resin of a perfluoroalkyl group-containing (meth) acrylic monomer Alternatively, a copolymer resin containing 1% by weight or more of the monomer (I) as a copolymerization component is used as a dispersion stabilizer, and at least one radical-polymerizable monomer is used in an organic liquid in the presence of the resin. The present invention relates to a method for polymerizing a body to produce a stable dispersion of polymer particles insoluble in the organic liquid.

When a homopolymer resin of the monomer (I) or a copolymer resin containing the monomer (I) as a copolymer component is used as a dispersion stabilizer of NAD, a coating containing the NAD as a main component is used. The continuous phase of the formed film is mainly a dispersion stabilizer. It comprises a homopolymer resin of the monomer (I) or a copolymer resin containing the monomer (I) as a copolymerization component.
Therefore, as the characteristics of the coating film surface, the characteristics of the continuous phase, that is, the characteristics of the perfluoroalkyl group are mainly exhibited.

Moreover, the thermal and mechanical properties that the coating film must have are reinforced by the polymer particle portion of NAD.

Further, the perfluoroalkyl group need only be present in the continuous phase and does not need to be present inside the NAD polymer particles, and therefore, as compared with the perfluoroalkyl group-containing polymer resin solution obtained by conventional solution polymerization, By copolymerizing the monomer (I) in a smaller amount, equivalent properties based on perfluoroalkyl groups can be exhibited. That is, it is possible to obtain a coating film which is significantly advantageous in terms of price.

The dispersion stabilizer resin is a homopolymer resin of the monomer (I) or contains the monomer (I) in an amount of 1% by weight or more, preferably 10% or more as a copolymerization component. Further, the dispersion stabilizer resin has to have a low polarity because it must be dissolved in an organic liquid having a low polarity.

Further, as the radical-polymerizable acrylic monomer that can be copolymerized with the monomer (I), those conventionally used when producing an acrylic polymer by radical polymerization can be similarly used. Acrylic acid, methacrylic acid, crotonic acid, N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, acrylic acid Acrylic acid such as butyl, hexyl acrylate, octyl acrylate, lauryl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, butyl methacrylate, hexyl methacrylate, octyl methacrylate, lauryl methacrylate or the like. METAKU C _{1 to 18} alkyl esters of Le acid; hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate,
_C2-8 hydroxyalkyl ester of acrylic acid or methacrylic acid such as hydroxypropyl methacrylate;
Examples thereof include acrylonitrile and methacrylonitrile.

These radical-polymerizable acrylic monomers can be used alone or in combination of two or more, and if necessary, a part of the acrylic monomer can be used for other radical polymerization. The monomer may be replaced with a vinyl aromatic compound such as styrene, α-methylstyrene, vinyltoluene and the like.

The above-mentioned acrylic copolymer used as the dispersion stabilizer resin is advantageous in that it has a polymerizable double bond in the molecule, and the introduction of the polymerizable double bond is, for example, a copolymerization component of the acrylic copolymer. For example, using a carboxyl group-containing monomer such as acrylic acid or methacrylic acid, and reacting this carboxyl group with a glycidyl group-containing unsaturated monomer (eg, glycidyl acrylate, glycidyl methacrylate, allyl glycidyl ether, etc.) However, of course, the reaction can also be carried out by reacting the glycidyl group-containing acrylic copolymer with the carboxyl group-containing unsaturated monomer.

Other examples of such a combination include an acid anhydride group and a hydroxyl group, an acid anhydride group and a mercaptan group, an isocyanate group and a hydroxyl group, and the like. The general conditions under which addition reactions occur between such reactive group combinations are well known, and the temperatures at which those reactions occur are dependent upon the particular combination of reactive groups selected, and by the use of catalysts. It goes without saying that it can be modified.

By the reaction as described above, the dispersion stabilizer resin can have at least 0.1 polymerizable double bonds in one molecule on average.

Of course, in the present invention, the dispersion stabilizer resin may not have a polymerizable double bond, but the introduction of the polymerizable double bond forms a covalent bond between the polymer forming the particles and the dispersion stabilizer. Further, the storage stability and mechanical stability of the dispersion can be further improved.

The molecular weight of the homopolymer resin of the monomer (I) as a dispersion stabilizer or the copolymer resin containing the monomer (I) as a copolymerization component has a weight average molecular weight of about 5,000 to about 100,000.
(Number average molecular weight is about 1000 to about 60,000), preferably about 5000
Conveniently it is in the range of to about 50,000. When the molecular weight is less than about 5,000, the dispersed particles are insufficiently stabilized and easily aggregate and settle. On the other hand, when the molecular weight exceeds about 50,000, the viscosity becomes extremely high and it may be difficult to handle.

Polymerization is carried out using a radical initiator. Examples of usable radical polymerization initiators include azo initiators such as 2,2′-azobisisobutyronitrile and 2,2′-azobis (2,4-dimethylvaleronitrile), benzoylperoxide, and laurylperoxide. Examples thereof include peroxide-based initiators such as oxide and tert-butyl peroctoate. These polymerization initiators are generally used in an amount of 0.2 to 10 parts by weight, preferably 0.5 to 5 parts by weight, per 100 parts by weight of the monomers used for the polymerization. The reaction temperature during polymerization may be a temperature in the range of 60 to 160 ° C., and the reaction can be usually completed in 1 to 15 hours.

The above-mentioned dispersion stabilizer resin used in the present invention may be used alone, or may be used with different copolymer composition and molecular weight.
They may be used in combination of two or more, and if necessary, other dispersion stabilizers such as butyl etherified melamine-formaldehyde resin, alkyd resin, and general acrylic resin containing no monomer (I) as a copolymerization component. It is also possible to use together with a small amount of.

According to the present invention, at least one radically polymerizable monomer is polymerized in an organic liquid in the presence of the dispersion stabilizer resin as described above.

Although the dispersion polymer particles produced by the polymerization are not substantially dissolved in the organic liquid used for the polymerization, the organic liquid becomes a good solvent for the dispersion stabilizer resin and the radical polymerizable monomer. Is included.

Specific examples of such an organic liquid include hexane, heptane, octane, and other aliphatic hydrocarbons; benzene, toluene, xylene, and other aromatic hydrocarbons; alcohol-based, ether-based, ester-based, and ketone-based solvents such as isopropyl alcohol. n-butyl alcohol, i-butyl alcohol, octyl alcohol, cellosolve, butyl cellosolve, diethylene glycol monobutyl ether,
Methyl isobutyl ketone, diisobutyl ketone, ethyl acyl ketone, methyl hexyl ketone, ethyl butyl ketone, ethyl acetate, isobutyl acetate, acyl acetate, 2-
Examples thereof include ethylhexyl acetate and the like, and these may be used alone or in combination of two or more, but generally, they are mainly aliphatic hydrocarbons,
In addition to this, aromatic hydrocarbons and alcohols as described above,
A combination of ether-based, ester-based or ketone-based solvents is preferably used.

Further, those which are good solvents for the high molecular weight homopolymer resin of the monomer (I) or the high molecular weight copolymer resin containing 80% by weight or more of the monomer (I), for example, trichlorotrifluoroethane, metaxylene. Hexafluoride, tetrachlorohexafluorobutane and the like can be used if necessary.

The monomer that can be polymerized in the presence of the dispersion stabilizer resin and the organic liquid described above is not particularly limited as long as it is a radically polymerizable unsaturated monomer, and various kinds can be used. The representative ones are as follows.

(A) Ester of acrylic acid or methacrylic acid; for example, methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, butyl acrylate, hexyl acrylate, octyl acrylate, lauryl acrylate, methyl methacrylate, methacrylic acid. glycidyl acrylate, glycidyl methacrylate; ethyl, propyl methacrylate, isopropyl methacrylate, butyl methacrylate, hexyl methacrylate, octyl methacrylate, C _{1 to 18} alkyl esters of acrylic acid or Metakururi acid lauryl methacrylate and allyl acrylate, _C2-8 alkenyl ester of acrylic acid or methacrylic acid such as allyl methacrylate;
Hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, C _{2 to 8} hydroxyalkyl esters of acrylic acid or methacrylic acid such as hydroxyethyl methacrylate; allyl oxyethyl acrylate, _{C. 3 to} acrylic acid or methacrylic acid such as allyloxy methacrylate ₁₈ Alkenyloxyalkyl ester.

(B) Vinyl aromatic compound: For example, styrene, α-methylstyrene, vinyltoluene, p-chlorostyrene vinylpyridine.

(C) α, β-ethylenically unsaturated acids: eg acrylic acid, methacrylic acid, itaconic acid.

(D) Others: acrylonitrile, methacrylonitrile, methyl isopropenyl ketone; vinyl acetate, Veova monomer (Ciel chemical product), vinyl bropionate,
Vinyl pivalate etc. Of course, a monomer such as the monomer (I) may be used.

Particularly preferable among these monomers are monomers or monomer mixtures containing at least 40% by weight of acrylic acid or methacrylic acid ester.

Polymerization of the above monomers is carried out using a radical polymerization initiator. Examples of usable radical polymerization initiators include azo initiators such as 2,2-azoisobutyronitrile and 2,2′-azobis (2,4-dimethylvaleronitrile);
Benzoyl peroxide, lauryl peroxide, tert
There may be mentioned peroxide-based initiators such as butyl peroctoate, and these polymerization initiators are generally used in an amount of 0.2 to 10 parts by weight, preferably 0.5 to 5 parts by weight per 100 parts by weight of the monomers to be subjected to the polymerization.
It can be used within the range of parts by weight.

The amount of the dispersion stabilizer resin used in the previous period can be varied over a wide range depending on the type of the resin, etc., but generally 3 to 70% by weight based on the total amount of the monomer to be polymerized and the dispersion stabilizer. , Preferably in the range of 5 to 45% by weight.

Further, the total concentration of the monomer and the dispersion stabilizer in the organic liquid is generally 30 to 70% by weight, preferably 30 to 60% by weight.

The polymerization can be carried out by a method known per se, and the reaction temperature during the polymerization can be generally in the range of 60 to 160 ° C., and the reaction can be usually completed in 1 to 15 hours.

The non-aqueous dispersion liquid of the polymer particles produced by the method of the present invention described above has extremely excellent dispersion stability and can be used for applications such as paints, molded products, adhesives and fillers.

The dispersion liquid provided by the present invention can be used as it is, but if necessary, a colorant, a plasticizer, a curing agent and the like can be added. Examples of the colorant include dyes, organic pigments, and inorganic pigments. Known plasticizers include, for example, low molecular weight plasticizers such as dimethyl phthalate and dioctyl phthalate, vinyl polymer plasticizers,
High molecular weight plasticizers such as polyester-based plasticizers may be used, which may be mixed in the dispersion liquid in advance, or may be dissolved in a radical-polymerizable monomer at the time of manufacturing the dispersion liquid to form a dispersion liquid. It can also be distributed in the dispersed polymer particles. Further, as the curing agent, a cross-linking agent such as amino resin, epoxy resin and polyisocyanate may be used. Furthermore, fibrin, other acrylic resin,
It is also possible to blend and use an alkyd resin, a polyester resin, an epoxy resin or the like.

Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples. In Examples and Comparative Examples, parts and% are parts by weight and% by weight, respectively.

Example 1 Synthesis of Dispersion Stabilizer (A) 40 parts of isobutyl acetate and 40 parts of toluene were heated to reflux, the following monomers and polymerization initiators were added dropwise over 3 hours, and the mixture was aged for 2 hours.

2-perfluorooctylethyl methacrylate 50 parts Styrene 10 parts Isobutyl methacrylate 19 parts 2 Ethylhexyl methacrylate 10 parts 2-Hydroxyethyl methacrylate 10 parts Methacrylic acid 1 part 2,2'-Azobisisobutyronitrile 2 parts Acryl resin obtained The varnish had a nonvolatile content of 55%, a viscosity (Gardner, 25 ° C., the same applies hereinafter) G and a weight average molecular weight of about 16,000.

Synthesis of Dispersion Polymer Liquid Heptane (93 parts) Dispersion stabilizer (A) (98 parts) was charged into a flask and heated to reflux, and the following monomers and polymerization initiators were added dropwise over 3 hours, followed by aging for 2 hours.

Styrene 15 parts Methyl methacrylate 40 parts Acrylonitrile 30 parts 2-Hydroxyethyl methacrylate 15 parts Tertiary butyl peroxy 2-ethylhexanoate 1.5 parts The obtained liquid has a nonvolatile content of 53%, a viscosity A, and a particle size of polymer particles ( The measurement was carried out by an electron microscope, and the same shall apply hereinafter). No precipitate or coarse particles were found even after standing still in a greenhouse for 3 months.

The surface energy of the dry coating film applied to the glass plate (measured by the contact angle using water and paraffin, the same applies below) is 14
It was as low as dyncm ^-1 .

Example 2 Synthesis of Dispersion Stabilizer (B) Isobutyl acetate 40 parts Toluene 40 parts was heated to reflux, the following monomers and polymerization initiators were added dropwise over 3 hours, and the mixture was aged for 2 hours.

2-perfluoroisononylethyl methacrylate 30 parts Styrene 15 parts Isobutyl methacrylate 30 parts Lauryl methacrylate 14 parts 2-Hydroxyethyl methacrylate 10 parts Methacrylic acid 1 part 2,2'-Azobisisobutyronitrile 1.8 parts Acryl resin obtained The varnish had a nonvolatile content of 55%, a viscosity J and a weight average molecular weight of about 18,000.

Synthesis of dispersion polymer liquid 82 parts of heptane and 121 parts of dispersion stabilizer (B) were placed in a flask and heated to reflux, and the following monomers and
The polymerization developer was added dropwise over 3 hours, and the mixture was aged for 2 hours.

Styrene 15 parts Methyl methacrylate 30 parts Acrylonitrile 40 parts 2 Hydroxyethyl methacrylate 15 parts 2,2'-azobisisobutyronitrile 2 parts The obtained liquid has a nonvolatile content of 55%, a viscosity C, and a polymer particle diameter of 0.15. It was a milky white stable low-viscosity polymer dispersion of ˜0.20 μm. No precipitation or coarse particles were observed even after standing at room temperature for 3 months.

The surface energy of the dry coating film applied to the glass plate is 16 dy.
It was as low as n.cm ^-1 .

Example 3 Synthesis of Dispersion Stabilizer (C) 80 parts of meta-xylene hexafluoride was heated and kept at 110 ° C., the following monomers and polymerization initiators were added dropwise over 3 hours, and the mixture was aged for 2 hours. It was

2-perfluorooctylethylmethacrylate 100 2,2'-azobisisobutyronitrile 2 The obtained acrylic resin varnish has a nonvolatile content of 55% and a viscosity of C
And the weight average molecular weight was about 16,000.

Synthesis of dispersion polymer liquid Cyclohexane 20 parts Metaxylene hexafluoride 62 parts Dispersion stabilizer (C) 121 parts Charged to a flask and heated to 95 ° C, the following monomers and polymerization initiators are added dropwise over 3 hours. Then, it was aged for another 2 hours.

Styrene 15 parts Methyl methacrylate 42 parts Acrylonitrile 20 parts Glycidyl methacrylate 5 parts Acrylic acid 3 parts 2 Hydroxyethyl acrylate 15 parts 2,2'-azobisisobutyronitrile 2 parts The obtained liquid has a nonvolatile content of 55% and a viscosity B. It was a milky-white stable low-viscosity polymer dispersion having a polymer particle size of 0.18 to 0.20 μm. The inside of the particles was crosslinked by the reaction between the epoxy group of glycidyl methacrylate and the carboxyl group of acrylic acid. No precipitate or coarse particles were observed even when the dispersion was allowed to stand at room temperature for 3 months. The surface energy of the dry coating film applied to the glass plate is 11 dyn.cm ^-1.
Was low.

Example 4 Synthesis of Dispersion Stabilizer D Isobutyl acetate (50 parts) Toluene (30 parts) was heated to reflux, and the following monomers and polymerization initiators were added dropwise over 3 hours, followed by aging for 3 hours.

2-perfluorooctylethyl methacrylate 50
Parts styrene 10 parts isobutyl methacrylate 19 parts 2-ethylhexyl methacrylate 10 parts 2-hydroxyethyl methacrylate 10 parts methacrylic acid 1 part tert-butyl peroxy 2 ethylhexanoate 3 parts The resulting acrylic resin varnish has a non-volatile content of 55% and a viscosity. H and a weight average molecular weight of about 16,000. Then, glycidyl methacrylate 0.8 part 4-tert-butylpyrocatechol 0.02 part dimethylaminoethanol 0.1 part was added to the total amount of the above varnish, and the reflux reaction was carried out for 5 hours to introduce a copolymerizable double bond into the dispersion stabilizer molecular chain. did. The number of introduced double bonds was about 0.6 per one molecular chain as measured by the resin acid value.

Synthesis of Dispersion Polymer Liquid Heptane (93 parts) Dispersion stabilizer D (98 parts) was charged into a flask and heated to reflux, and the following monomers and polymerization initiator were added dropwise over 3 hours, followed by aging for 2 hours.

Styrene 10 parts Methyl methacrylate 45 parts Acrylonitrile 25 parts 2-Perfluorooctylethyl methacrylate 5 parts 2-Hydroxyethyl methacrylate 15 parts Tertiary butyl peroxy 2-ethylhexanoate 1.5 parts The obtained liquid has a nonvolatile content of 55% and a viscosity of H, a milky white stable low-viscosity polymer dispersion having a particle size of polymer particles of 0.2 to 0.3 μm.

No precipitate or coarse particles were observed even when the dispersion was allowed to stand at room temperature for 3 months. The surface energy of the dried coating film applied to the glass plate was as low as 13 dyn.cm ^-1 .

Comparative Example 1 Synthesis of Dispersion Stabilizer E 40 parts of isoptyl acetate and 40 parts of toluene were heated to reflux, the following monomers and polymerization initiators were added dropwise over 3 hours, and the mixture was aged for 2 hours.

Styrene 10 parts Isoptyl methacrylate 69 parts 2 Ethylhexyl methacrylate 10 parts 2 Hydroxyethyl methacrylate 10 parts Methacrylic acid 1 part 2,2'-Azobisisobutyronitrile 2 parts The acrylic resin varnish obtained has a nonvolatile content of 55% and a viscosity of H
And the weight average molecular weight was 16,000.

Synthesis of Dispersion Polymer Liquid Heptane (93 parts) Dispersion stabilizer (E) (98 parts) was placed in a flask and heated to reflux, and the following monomers and polymerization initiator were added dropwise over 3 hours, followed by aging for 2 hours.

Styrene 15 parts Methyl methacrylate 40 parts Acrylonitrile 30 parts 2-Hydroxyethyl methacrylate 15 parts Tertiary butyl peroxy 2-ethylhexanoate 1.5 parts The obtained liquid is non-volatile content 53%, viscosity B, particle size of polymer particles
It was a 0.2-0.3 μm milky white stable low-viscosity polymer dispersion. No precipitation or coarse particles were observed even after standing at room temperature for 3 months.

The surface energy of the dry coating film applied to the glass plate is 35 dyn.
It was at the same level as cm ⁻¹ and the surface energy of a dry coating film obtained from a general acrylic resin varnish.

Comparative Example 2 The surface energy of the dried coating film of the dispersion stabilizer (C) itself applied to the glass plate was as low as 11 dyn.cm ^-1 , but it was a brittle coating film with cracks.

On the other hand, in Examples, the coating films formed by the polymer dispersion liquid including those in Example 3 were all tough coating films.

Comparative Example 3 The surface energy of the dried coating film of the dispersion stabilizer (B) itself applied to the glass plate was 16 dyncm ⁻¹ . Comparing this with the polymer dispersion of Example 3, only 40% of the coating obtained from the dispersion stabilizer (B) was perfluoro in the coating obtained from the polymer dispersion. It was found to exhibit the same level of surface energy despite the inclusion of alkyl groups.

Claims (3)

[Claims] 1. The following general formula (In the formula, R represents a hydrogen atom or a methyl group, and n is 1 to
Hf represents an integer of 10 and Rf represents a linear or branched perfluoroalkyl group having 3 to 21 carbon atoms.) A homopolymer resin of a perfluoroalkyl group-containing (meth) acrylic monomer Alternatively, a copolymer resin containing 1% by weight or more of the perfluoroalkyl group-containing (meth) acrylic monomer as a copolymerization component is used as a dispersion stabilizer resin, and in an organic liquid in the presence of the resin, A method for producing a stable dispersion of polymer particles insoluble in the organic liquid by polymerizing at least one kind of radically polymerizable unsaturated monomer. 2. The perfluoroalkyl group-containing (meth)
Acrylic monomer The method for producing a stable dispersion according to claim 1, wherein 3. A stable dispersion according to claim 1, wherein the dispersion stabilizer resin has at least 0.1 weight double bonds in one molecule on average. A method for producing a liquid.