WO2015138163A1

WO2015138163A1 - Process for preparing fluorinated polymeric hollow nanospheres

Info

Publication number: WO2015138163A1
Application number: PCT/US2015/017915
Authority: WO
Inventors: Hau-Nan LEE; Anilkumar Raghavanpillai; Stephanie A. BERNARD
Original assignee: E I Du Pont De Nemours And Company
Priority date: 2014-03-11
Filing date: 2015-02-27
Publication date: 2015-09-17

Abstract

The disclosure provides a process for preparing a fluorinated polymeric hollow nanosphere comprising: providing a mixture comprising water, at least one non-reactive solvent, at least one acrylic or styrenic monomer; at least at least one fluorinated acrylic monomer; an initiator; and at least one surfactant; shearing the components of the mixture with high shear energy at an energy density of at least 10^6 J/m^3 to form a mini-emulsion; and heating to at least about 50C to form, in one step, a fluorinated polymeric hollow nanosphere.

Description

TITLE

PROCESS FOR PREPARING FLUORINATED POLYMERIC HOLLOW

NANOSPHERES BACKGROUND OF THE DISCLOSURE

Field of the Disclosure

The present disclosure relates to a process for making fluorinated polymeric nanospheres, more particularly to a preparation process for making fluorinated polymeric nanospheres utilizing a mini-emulsion preparation process and their use in coating compositions.

Description of the Related Art

Nanospheres are submicroscopic colloidal systems composed of a solid or liquid core surrounded by a thin polymer or inorganic shell. This solid or liquid core is removed to form hollow nanospheres. Such core- shell systems may be prepared from micro or miniemulsions via

polymerization reaction at the interface of the droplets, the so-called interfacial polymerization reaction. Interfacial polymerization occurs at the interface of two immiscible phases, for example, oil and water, and a thin shell is formed. In the formation of the shell, the monomers are in either oil or water phase to participate in the reaction. Typically, for the

preparation of core-shell nanocapsules via interfacial polymerization, a microemulsion or miniemulsion is first prepared, either water in oil or oil in water, wherein in the former nanocapsules with an aqueous core suspended in oil are formed and in the latter nanocapsules with an oily core suspended in water are formed. Existing processes for the

preparation of fluorinated polymeric hollow particles either require a two- step polymerization process, or produce particles that are too large (> 1 pm).

A need exists for a fluorinated polymeric hollow nanosphere via an interfacial miniemulsion polymerization reaction. It is also needed that the process can be prepared through a one step process and provide superior performance for opacity enhancement and easy-clean property in architectural and industrial coatings.

SUMMARY OF THE DISCLOSURE

In a first aspect, the disclosure provides a process for preparing a fluorinated polymeric hollow nanosphere comprising:

a) providing a mixture comprising water, at least one non-reactive solvent, at least one acrylic or styrenic monomer; at least one fluorinated acrylic monomer having general formula Rf(CH2)m-A- C(O)C(R)=CH₂ or Rf(CH2)m-A-C(O)-B-(CH₂)nOC(O) C(R)=CH₂, wherein Rf is a linear or branched perfluoroalkyl group comprisng 1 10 carbon atoms, m = 1 -5, n = 1 -5, R = H, CI, Chb, A and B = O or NH; an initiator; and at least one surfactant;

b) shearing the components of the mixture from (a) with high shear energy at an energy density of at least 10^Λ6 J/m^A3 to form a mini- emulsion; and

c) heating to at least about 50°C, more typically about 50° to about 90°C; and still more typically about 60° to about 80°C to form, in one step, a fluorinated polymeric hollow nanosphere.

By non- reactive solvent we mean that the solvent does not substantially react, more typically does not react, with any of the other components added to the reaction.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is the structure of the resulting particles from Example 1 that analyzed using transmission electron microscopy.

DETAILED DESCRIPTION OF THE DISCLOSURE

In this disclosure "comprising" is to be interpreted as specifying the presence of the stated features, integers, steps, or components as referred to, but does not preclude the presence or addition of one or more features, integers, steps, or components, or groups thereof. Additionally, the term "comprising" is intended to include examples encompassed by the terms "consisting essentially of and "consisting of." Similarly, the term "consisting essentially of is intended to include examples encompassed by the term "consisting of."

In this disclosure, when an amount, concentration, or other value or parameter is given as either a range, typical range, or a list of upper typical values and lower typical values, this is to be understood as specifically disclosing all ranges formed from any pair of any upper range limit or typical value and any lower range limit or typical value, regardless of whether ranges are separately disclosed. Where a range of numerical values is recited herein, unless otherwise stated, the range is intended to include the endpoints thereof, and all integers and fractions within the range. It is not intended that the scope of the disclosure be limited to the specific values recited when defining a range.

In this disclosure, terms in the singular and the singular forms "a," "an," and "the," for example, include plural referents unless the content clearly dictates otherwise. Thus, for example, reference to "fluorinated polymeric hollow nanosphere", "the fluorinated polymeric hollow

nanosphere", or "a fluorinated polymeric hollow nanosphere" also includes a plurality of fluorinated polymeric hollow nanospheres

The disclosure relates to a process for preparing a fluorinated polymeric hollow nanosphere. These fluorinated polymeric hollow nanospheres are useful as hiding or opacifying agents and provide easy- clean property in coating and molding compositions. They are also useful as drug delivery systems in the pharmaceutical and medical industries; in food, personal care and cosmetics; and agriculture.

These nanospheres have a particle size of about 5 nm to about 400 nm, more typically about 50 nm to about 300 nm, and still more typically about 100 nm to about 250 nm.

The solids concentration of these nanospheres dispersion is at least 5% solids, more typically about 5 wt% to about 30 wt%, still more typically about 5 wt% to about 20 wt%.

The fluorinated polymeric hollow nanospheres are prepared by a process comprising: (a) providing a mixture comprising water, at least one non- reactive solvent, at least one acrylic or styrenic monomer; at least one fluorinated acrylic monomer having general formula Rf(CH₂)m-A-C(O)C(R)=CH2 or R_f(CH₂)_m-A-C(O)-B- (CH₂)nOC(O) C(R)=CH₂, wherein R_f is a linear or branched perfluoroalkyl group comprisng 1 -10 carbon atoms, m = 1 -5, n = 1 -5, R = H, CI, Chb, A and B = O or NH; an initiator; and at least one surfactant;

(b) shearing the components of the mixture from (a) with high shear energy at an energy density of at least 10^Λ6 J/m^A3 to form a mini-emulsion; and

(c) heating to at least about 50°C, more typically about 50°C to about 90 °C; and still more typically about 60°C to about 80°C to form, in one step, a fluorinated polymeric hollow nanosphere.

The non-reactive solvent may be an alkane, a hydrocarbon oil, aromatic hydrocarbon or halogenated hydrocarbon liquid, more typically alkane or hydrocarbon oil.

The at least one acrylic or styrenic monomer may be methyl methacrylate, methyl acrylate, n-butyl methacrylate, t-butyl methacrylate, t- butyl acrylate, ethyl glycol dimethacrylate, styrene or divinylbenzene; more typically methyl methacrylate or styrene. The monomer is present in the amount of about 5 wt % to about 30 wt %, more typically about 5 wt% to about 20 wt%, based on the total weight of all components.

The fluorinated acrylic monomer may be a monomer having a general formula Rf(CH₂)_m-A-C(O)C(R)=CH₂, where Rf is a linear or branched perfluoroalkyl group containing 1 -10 carbon atoms, m = 1 -5, R = H, CI, Chb, A = O or NH; more typically 1 H,1 H,2H,2H-perfluorooctyl methacrylate, 1 H,1 H,2H,2H-perfluorooctyl acrylate, 1 H,1 H,2H,2H- perfluorodecyl methacrylate, and 1 H,1 H,2H,2H-perfluorodecyl acrylate. The above monomers are available from E. I. du Pont de Nemours and Company, Wilmington, DE or could be prepared via the reaction of corresponding acyloyl/methacryoyl chloride with fluorinated alcohol or fluorinated amine in presence of a base.

The fluorinated acrylic monomer may also be a monomer having a general formula Rf(CH2)m-A-C(O)-B-(CH₂)nOC(O) C(R)=CH₂, where Rf is a linear or branched perfluoroalkyl group containing 1 -10 carbon atoms, m =

1 -5, n = 1 -5, R = H, CI, CH3, A and B = O or NH; more typically a monomer with Rf = CeFi3, m =2, A = O, NH, B = NH, n = 3, R = CH3 or H.

These monomers are prepared via the reaction of a fluorinated alcohol or amine with isocyanatoalkylacrylate/methacrylate to provide corresponding carbamate or urea. Some carbamate monomers in the general structure

Rf(CH2)m-A-C(O)-B-(CH₂)nOC(O) C(R)=CH₂ could be prepared via the reaction of hydroxyalkyl acrylate/methacrylate with

perfluoroalkylethylisocyanate. The fluorinated acrylic monomer is present in the amount of about 1 wt % to about 10 wt %, more typically about 2 wt% to about 5 wt%, based on the total weight of all components.

Some suitable initiators include azo compounds such as 2,2'- azobisisobutyronitrile (AIBN) or 2,2'-azobis(2-methylpropionamide) dihydrochloride (AIBA); metal persulfate such as potassium persulfate

(KPS) or sodium persulfate; more typically AIBN or KPS. The initiator is present in the amount of about 0.05 wt % to about 0.5 wt %, more typically about 0.1 wt% to about 0.3 wt%, based on the total weight of all components.

Some suitable surfactants include cetyltrimethylammonium bromide (CTAB), lauryltrimethylammonium bromide, dodecyltrimethylammonium bromide, octyltrimethylammonium bromide, sodium dodecyl sulfate

(SDS), sodium dodecylbenzene sulfonate (SDBS), dioctylsulfosuccinate , nonionic surfactants such as alkylphenol polyoxyethylene,

polyoxyethylene glycol alkyl ethers, polyoxypropylene glycol alkyl ethers, octylphenol ethoxylates, or poloxamers, more typically SDS, SDBS or CTAB. Some useful commercially available surfactants series include Triton X^® manufactured by The Dow Chemical Company, Brij^®

manufactured by Croda International PLC, or Pluoronic^® manufactured by BASF. The surfactant concentration is about 0.001 wt % to about 5 wt %, more typically about 0.1 wt% to about 2 wt%, based on the total weight of all components.

The monomers to non-reactive solvent ratio is about 0.1 to about 6, more typically about 0.5 to about 3, still more typically about 0.5 to about 2; oil to water or water to oil ratio is about 0.01 to about 0.55, more typically about 0.05 to about 0.25; and surfactant concentration is about 0.001 wt % to about 5 wt %, more typically about 0.1wt% to about 2 wt%, based on the total weight of all components. The water phase comprises water and surfactant and the oil phase comprises at least one non-reactive solvent, at least one acrylic or styrenic monomer; and at least one fluorinated acrylic monomer having general formula Rf(CH2)m-A- C(O)C(R)=CH₂ or Rf(CH2)m-A-C(O)-B-(CH₂)nOC(O) C(R)=CH₂, wherein R_f is a linear or branched perfluoroalkyl group comprisng 1 -10 carbon atoms, m = 1 -5, n = 1 -5, R = H, CI, Chb, A and B = O or NH. The initiator may be considered to be in either the water phase or oil phase. It is important because the combination of monomers to non-reactive solvent ratio, oil to water or water to oil ratio and surfactant level determine the particle size, hollow or non-hollow particle structure, and the shell thickness.

The mixture in step (a) may be prepared in any glass container or stainless steel reaction vessel.

The mixture of the above components is then sheared at an energy density of at least about 10^Λ6 J/m^A3, more typically about 10^Λ7 J/m^A3 to about 5^*10^Λ8 J/m^A3, to form a mini-emulsion. Some useful means for shearing include an ultrasonic disruptor, high speed blender, high pressure homogenizer, high shear disperser, membrane homogenizer or colloid mill, more typically an ultrasonic disruptor, high speed blender, or a high pressure homogenizer. Typically shearing occurs for a period of about 5 to about 120 minutes depending on amount of emulsion needed to be prepared and desired emulsion size range, more typically about 30 minutes to about 60 minutes. Typically, shearing is accomplished at room temperature. Optionally, a defoamer may be needed to avoid foaming during emulsifying. Some suitable defoamers include BASF Foamaster®, Dow Corning® 71 and 74 Antifoams. The mini-emulsion formed in step (b) is then heated to at least about 50°C, more typically about 50°C to about 90°C; and still more typically about 60°C to about 80°C to form, in one step, a fluorinated polymeric hollow nanosphere. Heating may be accomplished using hot plate, heating mantle or any other heating method.

Applications:

These fluorinated polymeric hollow nanospheres are useful as hiding or opacifying agents in coating and molding compositions. They also provide water and oil repellency, easy to clean and or dirt-pickup resistance properties in coating and molding compositions. They are also useful as drug delivery systems in the pharmaceutical and medical industries; in food, personal care and cosmetics; and agriculture.

EXAMPLES

Glossary:

AIBN 2,2'-azobisisobutyronitrile

CTAB cetyltrimethylammonium bromide

Example 1 :

An oily mixture which contained 1 .0 g of hexadecane, 7.36 g of octane, 2.84 g of methyl methacrylate, 0.36 g of ethylene glycol dimethacrylate, 0.36 g of styrene, 3.65 g of 1 H,1 H,2H,2H-perfluorooctyl methacrylate and 0.16 g of AIBN was first prepared, and added to a water solution which contains 84.0 g of water, 0.18 g of CTAB and 0.1 g of defoamer (Foamaster® 1 1 1 , BASF). Miniemulsification was achieved by shearing the mixture for 30 minutes with a high speed blender at 9500 rpm. After forming a stable miniemulsion, the polymerization was started by heating to 70°C for at least 16 hours. The structure of the resulting particles was analyzed using transmission electron microscopy and shown in Figure 1 . The average particle size of the resulting hollow particles determined by dynamic light scattering is 143.3 nm with a polydispersity of 0.178.

Claims

CLAIMS What is claimed is:

1 . A process for preparing a fluorinated polymeric hollow

nanosphere comprising:

(a) providing a mixture comprising water, at least one non- reactive solvent, at least one acrylic or styrenic monomer; at least one fluorinated acrylic monomer having a general formula Rf(CH₂)m-A-C(O)C(R)=CH2 or R_f(CH₂)_m-A-C(O)-B- (CH₂)nOC(O) C(R)=CH₂, wherein R_f is a linear or branched perfluoroalkyl group comprisng 1 -10 carbon atoms, m = 1 -5, n = 1 -5, R = H, CI, Chb, A and B = O or NH; an initiator; and at least one surfactant;

(c) heating to at least about 50°C, more typically about 50° to about 90°C; and still more typically about 60°C to about 80°C to form, in one step, a fluorinated polymeric hollow nanosphere.

2. The process of claim 1 wherein heating is to about 50°C to about 90°C.

3. The process of claim 1 wherein heating is to about 60°C to about 80°C.

4. The process of claim 1 wherein the non-reactive solvent is an alkane, a hydrocarbon oil, aromatic hydrocarbon or halogenated hydrocarbon liquid.

5. The process of claim 4 wherein the non-reactive solvent is alkane or hydrocarbon oil.

6. The process of claim 1 wherein the at least one acrylic or styrenic monomer is methyl methacrylate, methyl acrylate, n-butyl methacrylate, t-butyl methacrylate, t-butyl acrylate, ethyl glycol

dimechacrylate, styrene or divinylbenzene.

7. The process of claim 6 wherein the at least one acrylic or styrenic monomer is methyl methacrylate or styrene.

8. The process of claim 1 wherein the fluorinated monomer having the general formula Rf(CH₂)_n-A-C(O)C(R)=CH2 is 1 H,1 H,2H,2H- perfluorooctyl methacrylate, 1 H,1 H,2H,2H-perfluorooctyl acrylate,

1 H,1 H,2H,2H-perfluorodecyl methacrylate, or 1 H,1 H,2H,2H-perfluorodecyl acrylate.

9. The process of claim 1 wherein the fluorinated monomer has the general formula Rf(CH2)m-A-C(O)-B-(CH₂)nOC(O) C(R)=CH₂ wherein Rf = CeFi3, m = 2, A = O or NH, B = NH, n = 3, R = CHs or H.

10. The process of claim 1 wherein the initiator is an azo

compound; or a metal persulfate.

1 1 . The process of claim 10 wherein the azo compound is 2,2'- azobisisobutyronitrile (AIBN) or 2,2'-azobis(2-methylpropionamide) dihydrochloride (AIBA).

12. The process of claim 10 wherein the metal persulfate is potassium persulfate (KPS) or sodium persulfate.

13. The process of claim 10 wherein the initiator is AIBN or KPS.

14. The process of claim 1 wherein the surfactant is

cetyltrimethylammonium bromide (CTAB), lauryltrimethylammonium bromide, dodecyltrimethylammonium bromide, octyltrimethylammonium bromide, sodium dodecyl sulfate (SDS), sodium dodecylbenzene sulfonate (SDBS), or dioctylsulfosuccinate , nonionic surfactants, octylphenol ethoxylates, or poloxamers.

15. The process of claim 14 wherein the surfactant is SDS, SDBS or CTAB.

16. The process of claim 1 wherein the mixture of the above components is then sheared at an energy density of about 10^Λ7 J/m^A3 to about 5^*10^Λ8 J/m^A3 form a mini-emulsion.

17. The process of claim 1 wherein the shearing means is an ultrasonic disruptor, high speed blender, high pressure homogenizer, high shear disperser, membrane homogenizer or colloid mill.

18. The process of claim 1 wherein the fluorinated hollow particle is a nanosphere having a diameter in the range of about 5 nm to about 400 nm.