Microcapsule with a porous or hollow core and ph-sensitive shell and use thereof

Patent metadata

Field	Value
Publication number	US-2020368117-A1
Application number	US-201916967937-A
Country	US
Kind code	A1
Filing date	Feb 1, 2019
Priority date	Feb 6, 2018
Publication date	Nov 26, 2020
Grant date	—

Abstract

The invention relates to a microcapsule comprising a hollow or porous core, the hollow or porous core being composed of a polymeric material and containing a component of a redox-initiator system, a shell, the shell being composed of a pH-sensitive material. The microcapsule can be used for formulating dental materials.

First claim

1 . A microcapsule comprising:
a hollow or porous core, the hollow or porous core being composed of a polymeric material and containing a component of a redox-initiator system, a shell, the shell being composed of a pH-sensitive material.

2 . The microcapsule of claim 1 , the polymeric material of the hollow or porous core comprising a (meth)acrylate.

3 . The microcapsule of claim 1 , the porous or hollow core being characterized by the following features alone or in combination:
having a spherical shape; having a diameter in the range of 1 to 200 μm; having a pore size from 10 to 200 nm; being mechanically stable.

4 . The microcapsule of claim 1 , the shell being characterized by the following features alone or in combination:
thickness: 0.1 to 5 μm; covering more than 85% of the surface of the porous or hollow core; soluble in acidic or basic components.

5 . The microcapsule of claim 1 , the pH-sensitive material being a polymer, in particular being a polymer comprising co-polymer(s) of methyl (meth)acrylate and diethylaminoethyl (meth)acrylate, co-polymer(s) of methyl (meth)acrylate, butyl methacrylate and dimethylaminoethyl (meth)acrylate, cellulose acetate phthalate, sodium carboxymethyl cellulose, hydroxy propyl methyl cellulose phthalate, polyvinyl acetate phthalate, co-polymer(s) of methacrylic acid and methyl (meth)acrylate, co-polymer(s) of methacrylic acid and alkyl (meth)acrylate, co-polymer(s) of methacrylic acid, methyl (meth)acrylate and methyl acrylate, or mixture thereof.

6 . The microcapsule of claim 1 , the component of a redox-initiator system being selected from reducing or oxidizing agents.

7 . The microcapsule according to claim 6 , the component of a redox-initiator system being a reducing agent selected from ascorbic acid component(s), tertiary amine component(s), sulfinate component(s), sulphite component(s), borane component(s), (thio)urea component(s), and (thio)barbituric acid component(s), saccharin, and metal salts thereof.

8 . The microcapsule according to claim 6 , the component of a redox-initiator system being an oxidizing agent selected from organic and inorganic peroxides, preferably hydroperoxide(s), ketone peroxide(s), diacyl peroxide(s), dialkyl peroxide(s), peroxyketal(s), peroxyester(s) and peroxydicarbonate(s), persulfate component(s) and mixtures thereof.

9 . A kit of parts comprising a Catalyst Paste and a Base Paste,
the Catalyst Paste comprising:
a microcapsule of claim 1 comprising a first component of a redox-initiator system,
the Base Paste comprising:
acidic or basic component,
a second component of the redox-initiator system.

10 . The kit of parts according to claim 9 , the Base Paste containing an acidic component being characterized by the following features alone or in combination:
pKs value: below 5; comprising an acidic moiety selected from a sulfonic, sulfinic, phosphoric, phosphonic, phosphinic, or carboxylic moiety; comprising one or more polymerizable moieties.

11 . The kit of parts of claim 9 , being characterized as follows:
the Catalyst Paste comprising:
the microcapsules as described in any of claims 1 to 7 comprising a reducing agent, curable non-acidic (meth)acrylate component(s),
filler(s),
optionally photo initiator(s),
the Base Paste B comprising:
acidic component(s),
curable (meth)acrylate component(s),
filler(s),
oxidizing agent,
optionally transition metal component(s),
the reducing component and the oxidizing agent forming a redox-initiator system for curing the curable (meth)acrylate component(s).

12 . A process of producing a pH-sensitive core-shell microcapsule of claim 1 , the process comprising the steps of:
providing a particle with a hollow or porous core and a component of a redox-initiator system, having the particle absorb the component of the redox-initiator system, coating the particle containing the absorbed component of the redox-initiator system with a pH-sensitive coating material.

13 . The process of claim 12 , the coating step being done by spray-drying, preferably at the glass transition temperature T g of the pH-sensitive coating material.

14 . A process of curing a curable composition, the process comprising the steps:
providing a Catalyst Paste comprising microcapsules of claim 1 , and a Base Paste comprising an acidic or basic component, wherein either the Catalyst Paste or the Base Paste or the Catalyst Paste and the Base Paste comprise curable components, mixing the Catalyst Paste and the Base Paste.

15 . Use of microcapsules of claim 1 for producing a dental or orthodontic composition.

16 . The use of claim 15 , wherein the dental or orthodontic composition is selected from cement, adhesive, and filling material.

Assignees

• 3M Innovative Properties Co

Inventors

• Claussen Kai U
• Mechernich Silke D
• Richter Mareike
• Hecht Reinhold
• Ludsteck Manfred
• Jurjevic Simone

Classifications

• C08F2/44 Primary

  Polymerisation in the presence of compounding ingredients, e.g. plasticisers, dyestuffs, fillers · CPC title

• C08F222/10

  Esters · CPC title

• A61K6/17

  Particle size · CPC title

• A61K6/889 Primary

  Polycarboxylate cements; Glass ionomer cements · CPC title

• A61C5/00

  Filling or capping teeth · CPC title