Core/shell copolymer dispersion whose shell comprises hydrolyzable organosilicon comonomers

• US 5,708,093 A
• Filed: 10/02/1995
• Issued: 01/13/1998
• Est. Priority Date: 03/04/1993
• Status: Expired due to Term

• Current Assignee: Wacker-Chemie GmbH (Dr. Alexander Wacker Familiengesellschaft Mit Beschrã¤Nkter Haftung)
• Original Assignee: Wacker-Chemie GmbH (Dr. Alexander Wacker Familiengesellschaft Mit Beschrã¤Nkter Haftung)
• Inventors: Bastelberger, Thomas, Lutz, Hermann, Heiling, Peter
• Primary Examiner(s): DEAN JR, RALPH H
• Application Number:
  US08/505,354
• Time in Patent Office: 834 Days
• Field of Search: 523/201, 525/288, 525/902
• US Class Current: 525/288
• CPC Class Codes: C04B 26/32 containing silicon
• CPC Class Codes: C08F 220/10 Esters
• CPC Class Codes: C08F 291/00 Macromolecular compounds obtained by polymerising monomers on to macromolecular compounds according to more than one of the groups C08F251/00 - C08F289/00
• CPC Class Codes: C09D 151/003 grafted on to macromolecular compounds obtained by reactions only involving unsaturated carbon-to-carbon bonds C09D151/04, C09D151/06 take precedence
• CPC Class Codes: C09J 151/003 grafted on to macromolecular compounds obtained by reactions only involving unsaturated carbon-to-carbon bonds C09J151/04, C09J151/06 take precedence
• CPC Class Codes: E04F 13/02 of plastic materials hardening after applying, e.g. plaster surface treatment in painting technique B44D; inorganic or bituminous masses C04B; organic plastics C08L ; implements for applying plasticised materials E04F21/02
• CPC Class Codes: Y10S 525/902 Core-shell

Abstract

The invention relates to core/shell copolymer dispersions whose shell comprises hydrolyzable organosilicon comonomers, the shell consisting of a copolymer comprising,

a) from 70 to 95% by weight of acrylic and/or methacrylic C₁ to C₁₀ alkyl esters of which from 20 to 80% by weight, based on the overall weight of a), have a water-solubility of not more than 2 g/l and from 80 to 20% by weight, based on the overall weight of a), have a water-solubility of at least 10 g/l,

b) from 5 to 25% by weight of one or more ethylenically unsaturated, functional and water-soluble monomers including a proportion of from 25 to 100% by weight, based on the overall weight of b), of unsaturated carboxylic acids, and

c) from 0.01 to 10% by weight of one or more olefinically unsaturated, hydrolyzable silicon compounds of the general formula R¹ --Si(OR²)₃,

and whose core, making up a proportion of from 75 to 98% by weight of the overall weight of the core/shell copolymer, consists of a polymer comprising

d) one or more comonomers from the group consisting of vinyl esters, acrylic and/or methacrylic esters, vinyl chloride, vinylaromatic compounds and ethylene.

Claims

1. A core/shell copolymer dispersion having a solid content of from 45 to 65% whose shell comprises hydrolyzable organosilicon comonomers, the proportion of the shell in the core-shell copolymer being from 2 to 25% by weight and the shell comprised of a copolymer consisting essentially of a) at least 70% by weight, based on the overall weight of the shell, of acrylic and/or methacrylic C₁ to C₁₀ alkyl esters of which from 20 to 80% by weight, based on the overall weight of a), have a water-solubility of not more than 2 g/l and from 80 to 20% by weight, based on the overall weight of a), have a water-solubility of at least 10 g/l, b) from 5 to 25% by weight, based on the overall weight of the shell, of one or more ethylenically unsaturated, functional and water-soluble monomers and wherein (b) is comprised of by weight, at least 25% and up to and including 100% of unsaturated carboxylic acids, and c) from 0.01 to 10% by weight, based on the overall weight of the shell, of one or more olefinically unsaturated, hydrolyzable silicon compounds of the general formula R¹ --Si (OR²)₃ in which R¹ is an organic radical which is olefinically unsaturated in the ω

-position, and R², which is identical or different at each occurrence, is a primary and/or secondary alkyl or acyl radical which is optionally substituted with alkoxy groups, and whose core, makes up a proportion of from 75 to 98% by weight of the overall weight of the core/shell copolymer, comprised of a polymer consisting essentially of d) one or more comonomers from the group consisting of vinyl esters, acrylic and/or methacrylic esters, vinyl chloride, aromatic vinyl compounds and ethylene.

2. A core/shell copolymer dispersion as claimed in claim 1, wherein the core/shell copolymer comprises from 5 to 15% by weight of a shell copolymer comprising

a) at least 80% by weight, based on the overall weight of the shell, of comonomer a), of which from 40 to 60% by weight comprises butyl acrylate and/or ethylhexyl acrylate and from 60 to 40% by weight, based in each case on the overall weight of the comonomers a), comprises ethyl acrylate and/or methyl methylacrylate,

b) from 5 to 15% by weight, based on the overall weight of the shell, of acrylic acid and/or methacrylic acid, optionally with acrylamide and/or methacrylamide,

c) from 0.5 to 10% by weight, based on the overall weight of the shell, of vinyltriethoxysilane, γ

-methacryloyloxypropyltriethoxysilane and/or trisacetoxyvinylsilane.

3. A core/shell copolymer dispersion as claimed in claim 1, wherein the core-shell copolymer comprises from 75 to 95% by weight of a core copolymer based on vinyl chloride-ethylene copolymers, vinyl chloride-ethylene-vinyl acetate copolymers, copolymers of vinyl chloride and ethylene with vinyl esters of α

-branched carboxylic acids having 9 and/or 10 carbon atoms, vinyl acetate-ethylene copolymers, copolymers of vinyl acetate with vinyl esters of α

-branched carboxylic acids having 9 and/or 10 carbon atoms, methyl methacrylate-butyl-acrylate copolymers, methyl methacrylate-2-ethylhexyl acrylate copolymers, copolymers of methyl methacrylate and butyl acrylate with vinyl esters of α

-branched carboxylic acids having 9 and/or 10 carbon atoms, styrene-butyl acrylate copolymers, styrene-2-ethylhexyl acrylate copolymers, copolymers of styrene and butyl acrylate with vinyl esters of a-branched carboxylic acids having 9 and/or 10 carbon atoms, or copolymers of styrene and 2-ethylhexyl acrylate with vinyl esters of α

-branched carboxylic acids having 9-and/or 10 carbon atoms.

4. A process for the preparation of core/shell copolymer dispersions as claimed in claim 1 by free-radical emulsion polymerization of from 2 to 25% by weight, based on the overall weight of comonomers a), b), c) and d), of a comonomer mixture comprising

a) at least 70% by weight, based on the overall weight of the comonomers a), b) and c), of acrylic and/or methacrylic C₁ to C₁₀ alkyl esters of which from 20 to 80% by weight have a water-solubility of not more than 2 g/l and from 80 to 20% by weight, based in each case on the monomers a), have a water-solubility of at least 10 g/l, with

b) from 5 to 25% by weight, based on the overall weight of the comonomers a), b) and c), of one or more ethylenically unsaturated, functional and water-soluble monomers and wherein (b) is comprised of by weight, at least 25% and up to 100% of unsaturated carboxylic acids, and c) from 0.01 to 10% by weight, based on the overall weight of the comonomers a), b) and c), of one or more olefinically unsaturated, hydrolyzable silicon compounds of the general formula R¹ --Si (OR²)₃ in which R¹ is an organic radical which is olefinically unsaturated in the ω

-position, and R², which is identical or different at each occurrence, is a primary and/or secondary alkyl or acyl radical which is optionally substituted with alkoxy groups, in which the constituents mentioned under a), b) and c), together with water and emulsifier, are initially charged to a reactor at a pH of from 2 to 5, polymerization is begun at a temperature of from 40°

to 90°

C. by adding an initiator, and, at a degree of conversion of at least 50% of the monomers mentioned under a), b) and c), the metered addition is begun of from 75 to 98% by weight, based on the overall weight of the comonomers a), b) c) and d), of one or more further olefinically unsaturated monomers d) from the group consisting of vinyl esters, acrylic and/or methacrylic esters, vinyl chloride, aromatic vinyl compounds and ethylene, and further emulsifier and/or initiator.

5. The process as claimed in claim 4, wherein the monomers mentioned under b) are introduced as initial charge together with deionized water, from 0.5 to 10 parts by weight of a preferably anionic emulsifier or emulsifier mixture, and a pH of from 2 to 5, is established, after addition of the monomers mentioned under a) and c) and the establishment of the polymerization temperature of from 40°

to 90°

C., the polymerization is begun by adding an initiator, and as soon as the monomers mentioned under a) to c) have reacted to the extent of from 40 to 99%, the metered addition of the monomers mentioned under d), of the remaining amount of emulsifier and the remaining amount of water in the form of a preemulsion is commenced, and after the end of the addition of the constituents d), the supply of initiator is maintained until the monomers employed, except for any ethylene used, have reacted to the extent of more than 98%.

6. The process as claimed in claim 4, wherein, in the case of the copolymerization of ethylene into the core polymer, from 1 to 10% by weight of the monomers d) are initially introduced together with the monomers a), b) and c) as a swelling agent, in which context the comonomers d) employed can only be those which lender the conditions of the polymerization of the shell polymer do not, or not to any great extent, undergo copolymerization with the monomers a), b) or c).

7. A polymer-bound plaster containing as a binder the core/shell copolymer dispersion of claim 1.

8. A heat insulating system containing as a binder the core/shell copolymer dispersion of claim 1.

9. An interior and exterior paint containing as a binder the core/shell copolymer dispersion of claim 1.

10. A tile adhesive containing as a binder the core/shell copolymer dispersion of claim 1.