Micro capsule having carbamide resin wall

A technology of microcapsules and isocyanurate, which is applied in the direction of microcapsule preparation, microsphere preparation, replication/labeling methods, etc., and can solve the problems of expensive and high cost of microcapsules

Inactive Publication Date: 2009-08-19
KEMIRA OY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0010] On the other hand, increasing the fraction of polyisocyanate as the main wall-forming species will cause the oil phase and the subsequent microcapsules to become more expensive, since suitable polyisocyanates will be high value added chemicals and thus high cost items

Method used

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  • Micro capsule having carbamide resin wall
  • Micro capsule having carbamide resin wall
  • Micro capsule having carbamide resin wall

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1a

[0095] Example 1a (comparative example)

[0096] A microcapsule dispersion was produced according to example 10 of US 5,635,211 (=EP-A-727 251 ) by using guanidine as crosslinker.

Embodiment 1b

[0097] Example 1b (this invention)

[0098] Corresponding microcapsules according to the invention were produced under the same conditions as in Example 1a by using guanidine carbonate as crosslinker instead of guanidine, and the two capsules were compared with respect to their properties (see table). The NCO content in Examples 1a and 1b was 21.6% and the isocyanurate content was 96.9%, based on the polyisocyanate used. Among them, hexamethylene diisocyanurate trimer accounts for >45 wt% and higher oligomer accounts for >30 wt%.

[0099] surface

[0100]

[0101] * Aging was assessed by comparing a copy of a properly aged CB (coated back) paper to a copy of an unaged CB paper as a reference. The higher the number, the stronger the copy.

[0102] ** Corresponding to the polyisocyanate content in the oil phase.

[0103] The microcapsules according to the invention show much better aging properties than those of the prior art, despite a significantly reduced wall frac...

Embodiment 2

[0104] Example 2 (this invention)

[0105] a) Production of microcapsule dispersions

[0106] The microcapsules that are used for carbonless copy paper are obtained by following steps: first by dissolving the coupler that is made up of 12g crystal violet lactone in 187.2g diisopropylnaphthalene at 120 ℃ and this solution and 20g embodiment 1 The polyisocyanurate was mixed at room temperature to prepare the oil phase. 280.8 g of a naphthenic isoparaffin mixture were added as extender. This oil phase was mixed with 442.3 g of an aqueous phase consisting of an aqueous solution of polyvinyl alcohol (5.3 g in 437 g of water), and the mixture was stirred to obtain a coarse pre-emulsion, which was mixed with a mixing siren (8950 rpm ) were emulsified for 8 minutes to obtain a fine emulsion. The obtained miniemulsion was mixed with an aqueous solution of guanidinium carbonate (7.0 g in 50.7 g of deionized water) at room temperature, the obtained mixture was heated to 60° C. with ...

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Abstract

A microcapsule whose walls comprise the reaction product of polyisocyanates, guanidine compounds and optionally amines, wherein the polyisocyanates have an isocyanurate content (based on the polyisocyanate) of at least 30% by weight, characterized in that The walls represent on average less than 9% by weight of the total weight of the microcapsules.

Description

technical field [0001] The present invention relates to microcapsules having walls comprising polyurea obtained by reaction of polyisocyanates, guanidine compounds and optionally amines, to a process for the production of these microcapsules and to carbon-free carbon. Background technique [0002] Carbonless copy paper is coated with a layer of microcapsules on their backside. The microcapsules contain a solution in oil of a coupler, so called because it is capable of undergoing a color change from colorless to colored in the presence of an acidic developer in a few seconds. [0003] Writing on the reverse side of the encapsulated paper causes the capsules to rupture and release under the pressure of the writing instrument when the encapsulated paper is placed on a developer-primed paper in such a manner that the capsules are required to be in direct contact with the developer The coupler is released so that a color image appears on the developer side. [0004] In a varia...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B01J13/18B41M5/165B01J13/14B01J13/16C08G18/32C08G18/79
CPCB01J13/14B41M5/165Y10T428/2985
Inventor M·克莱班G·克卢格J·魏瑟尔
Owner KEMIRA OY
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