CA1224037A - Method for the removal of free formaldehyde from a formaldehyde-containing suspension of microcapsules - Google Patents

Method for the removal of free formaldehyde from a formaldehyde-containing suspension of microcapsules

Info

Publication number
CA1224037A
CA1224037A CA000463703A CA463703A CA1224037A CA 1224037 A CA1224037 A CA 1224037A CA 000463703 A CA000463703 A CA 000463703A CA 463703 A CA463703 A CA 463703A CA 1224037 A CA1224037 A CA 1224037A
Authority
CA
Canada
Prior art keywords
formaldehyde
suspension
microcapsules
self
compound
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
CA000463703A
Other languages
French (fr)
Inventor
Peter Pinot De Moira
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Arjo Wiggins Ltd
Original Assignee
Wiggins Teape Group Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Wiggins Teape Group Ltd filed Critical Wiggins Teape Group Ltd
Application granted granted Critical
Publication of CA1224037A publication Critical patent/CA1224037A/en
Expired legal-status Critical Current

Links

Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B41PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41MPRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
    • B41M5/00Duplicating or marking methods; Sheet materials for use therein
    • B41M5/124Duplicating or marking methods; Sheet materials for use therein using pressure to make a masked colour visible, e.g. to make a coloured support visible, to create an opaque or transparent pattern, or to form colour by uniting colour-forming components
    • B41M5/165Duplicating or marking methods; Sheet materials for use therein using pressure to make a masked colour visible, e.g. to make a coloured support visible, to create an opaque or transparent pattern, or to form colour by uniting colour-forming components characterised by the use of microcapsules; Special solvents for incorporating the ingredients
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01JCHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J13/00Colloid chemistry, e.g. the production of colloidal materials or their solutions, not otherwise provided for; Making microcapsules or microballoons
    • B01J13/02Making microcapsules or microballoons
    • B01J13/20After-treatment of capsule walls, e.g. hardening
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10STECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S428/00Stock material or miscellaneous articles
    • Y10S428/914Transfer or decalcomania
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10TTECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00Stock material or miscellaneous articles
    • Y10T428/249921Web or sheet containing structurally defined element or component
    • Y10T428/249994Composite having a component wherein a constituent is liquid or is contained within preformed walls [e.g., impregnant-filled, previously void containing component, etc.]
    • Y10T428/249995Constituent is in liquid form
    • Y10T428/249997Encapsulated liquid

Landscapes

  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Dispersion Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Color Printing (AREA)
  • Manufacturing Of Micro-Capsules (AREA)

Abstract

ABSTRACT

METHOD FOR THE REMOVAL OF FREE FORMALDEHYDE FROM A
FORMALDEHYDE-CONTAINING SUSPENSION OF MICROCAPSULES

Free formaldehyde is removed from a formaldehyde-containing suspension of microcapsules by the addition of a compound having a B dicarbonyl group or a cyclic ketone.
The thus-treated microcapsules are particularly suitable for the production of self-contained pressure sensitive copying material in which the image-generating reactants are present in a single coating composition.

Description

33~7 METHOD FOR THE RE~OVAL OF FREE FORMALDEHYDE FRO~ A
_ .
FORMALDEHYDE-CONTAINING SUSPENSION OF ~ICROCAPSULES

The present invention relates to a method for the removal of free formaldehyde from a formaldehyde-containing suspension of microcapsules, particularly but not exclusively for use in self-contained pressure sensitive copying materials.

Self-contained pressure sensitive copying material comprises a sheet material which carries both pressure-rupturable microcapsules containing a colourless colour former material and a colour developer material reactive with the colourless colour former. ~hen the microcapsules are ruptured as a result of pressure from, for example, a typewriter key, the colourless colour for~er is released to react with the colour developer and produce an image.

Self-contained pressure sensitive copying materials of this general type are described in UK Patent No. 1524742 which is particularly concerned with the application of the microcapsules and colour developer (in this case a clay) in a single coating composition.

The microcapsules used in copying materials of this type may have walls containing urea and/or melamine formaldehyde precondensates such as those disclosed in UK
Patent No. 1507739.

One of the problems with this type of microcapsule is that free formaldehyde is evolved during the capsule 1~2'~37 manufacture. The same problem can arise even with capsules produced by coacervat;on if formaldehyde solution is used as a hardening agent and/or a preservati~e. This free for-maldehyde is undesirable from the users' point of view due to the unpleasant odour and irritant effects of the for-maldehyde, particularly when the microcapsule suspension is incorporated into a coating mix prior to coating onto a sheet material.
Several methods have been suggested in the art to overcome these undesirable effects. UK Patent No.
1,146,117 discloses the addition of sodium sulphite or urea to a microcapsule dispersion to remove free formaldehyde, whilst Japanese Patent Application No. 57-050541, published 25 March, 1982, discloses the addition of dihydroxyacetone to a microcapsule dispersion to remove the free formaldehyde. UK Patent No. 1,507,739 discloses the use of an ammonium compound for quenching free for-maldehyde. The last mentioned expedient, which has been commercially practised, has the drawback that the reaction product of the excess formaldehyde and the quenching agent may adversely affect the imaging ability of the copying paper. In transfer carbonless copying paper in which the microcapsules and colour developer are not together on one surface of the paper, this problem is not seriaus, but in self-contained paper the problem is more noticeable.
It is an object of the present invention to pro-vide a method for removing the free formaldehyde, or at least to reduce the amount present, without unacceptably impairing the image-forming ability of the copying material.

1~Z4~)3~7 According to the present invention there is pro-vided a method Eor producing a self-contained pressure sen-sitive copying material comprising the steps of coating a sheet material with a coating composition comprising a colour developer material, a formaldehyde-containing suspension of microcapsules containing a colour former solution and a compound having a ~ dicarbonyl group selected from the group consisting of malonic acid, acety-lacetone, malonamide and diethyl malonate or a cyclic ketone which is added to the suspension of microcapsules in an amount effective to remove free Eormaldehyde from the suspension.
Preferably the compound having a ~ dicarbonyl group is one selected from malonic acid, acetylacetone, ethylacetone acetate, malonamide, diethyl malonate or another malonic ester. Preferred cyclic ketones include cyclohexanone or cyclopentanone.
Preferably the compound having a ~ dicarbonyl group is added to the microcapsule suspension in an amount of 1 to 2% by weight of the suspension. The present inven-tion is particularly useful when the microcapsules used are those described in Example 4 of UK Patent No. 1,524,742.
Thus in a preferred embodiment of the present invention free formaldehyde is removed by adding acetylacetone to a suspension of microcapsules having walls comprising a urea-formaldehyde precondensate, a melamine-formaldehyde precon-densate and a water soluble polymer. The thus treated microcapsule suspension is mixed with an appropriate amount of particulate colour developer and the resulting com-position coated onto a sheet material in a single pass toproduce a self-contained pressure sensitive copying sheet.

.~22'~37 ,~, Preferably the colour develop~r l~ an acldl~ clay such as one of the acid-washed montmorillonite clay~ sold under the trade~a~k Silton by Uizusawa Industrlal C~emicals Ltd.
of Japan.

The quenching agent may alternatively be added to the microcapsule suspension after the colour developer has been added.

The present invention will now be illustrated by reference to the following e~amples:

10 E~ample 1
2.0g acetylaceto~e were added to lOOg capsule suspeDsion prepared according to UK Patent No. 1507739. This mi~ture was theD ~haken in a flask ~or one ~inute to remove the ~ree formaldehqde present in the capsule 15 suspension. After this period of time, there was no apparent odour of for~aldehyde and the atmosphere in the flask above the mi~ture was then tested with a "Lion"
formald~meter to determine the actual concentration of formaldehyde remaining.

20 The above procedure was then repeated using malonic acid and malonamide in place of acetylacetone. The following results were obtained.

Additive Quantity Level of added to Formaldehyde capsule ("Lio~" [ trade mark]
suspension Formaldemeter (lOOg) Reading) Acetylacetone 2.00g 8 ppm ~alonic acid 2~00g 53ppm 30 Nalonamide 2.00g 67ppm ~Z~37 E~ample 2 1.3g acetylacetone were added to a lOOg capsule suspension prepared according to UK Patent No. 1507739. This mixture was shaken as described in Exa~ple 1 and tested for the presence of formaldehyde. There was no odour of formaldehyde.

The capsule suspension was then combined ~ith a suspension of clay colour developer, (that sold under the trademark "Silton" by ~Sizusawa Industrial Chemicals), to pro~uce a 10 coating mix containing by weight on a dry basis 3~%
capsules, 32% clay, 19~ wheatstarch and lOZ latex. This coating mix was then coated onto a paper sheet using a laboratory Meyer bar coater.

The resultant coated sheet was then dried to produce a 15 self-contained copying paper. No odour of formaldehyde was apparent during the drying.

The coated sheet was then submitted to a standard calender intensity (CI) test to illustrate that the use of acetylacetone to remove the free formaldehyde does not 20 unacceptably interfere with the ima~e-producing properties of the self-contained copying paper.

The calender intensity (CI) test in this case involves passing strips of the paper under test through a laboratory calender to rupture the capsules and thereby 25 produce a colour on the test strip, measuring the reflectance of the thus coloured strip (I) after allowing 2 minutes for the colour to develop and egpressing
3~

the result (I/IO) as a percentage of an unused Control strip (Io). Thus the lower the calender intensity value (I/IO) the more intense the developed colour. The CI value obtained was 66.1 showing that the i~age-producin~ properties of the self-contained copying sheet are acceptable.

A capsule emulsion was prepared as described in U~ Patent No 1507739.

10 3.51g. acetylacetone quenching agent were then added to 281.87g of the above mentioned capsule emulsion such that the quenching agent was present in an a~ount of 1.2~ by weight of the enulsion. After stirring gently in a stoppered flask for a few minutes the free for~aldehyde 15 level was measured with a Drager tube.

The above procedure was then repeated using cyclopentanone, cyclohe~anone and ethylacetoacetate in place of the acetylacetone as the quenching agents.

Additionally, by way of control, the formaldehyde level 20 was ~easured in the absence of a quenching agent.

A comparative e~ample in which ammonium sulphate (a commercially used quenching agent) was substituted for acetylacetone, was also carried out. The results are shown in Table 3.

TABL
AdditivsLevel of Formaldehyde ppm nonegreater than 50 (NH4)2 S0~appro~imately 10 5 acetylacetone " 11 cyclopentanone" 30 cyclohexanone " 30 ethylacetoacetate" 30 Whilst the a~onium sulphate appears to be the most 10 effective at quenching the free formaldehycle, a~ter standing it was noticed that the amount of free formaldehyde increased whilst this did not occur with the other quenching agents.

15 The treated capsule emulsions ~rom E~a~ple 3 were then co~bined with a suspension of clay colour developer, ("Silton") to produce a coa$ing mix containing by weight on a dry basis 33% capsules, 34~ clay, 21% wheatstarch and 11% latex. The coating ~i~ was then coated onto a paper 20 sheet using a laboratory Meyer bar coater at a coatweight of between 8.5 and 9.5 gm~2.

The resultant coated sheet was then dried to produce a self-contained copying paper and the coated sheet subjected to a standard calendar intensity test as 25 described in Exanple 2. The reflectance was neasured after allowing 2 ~inutes for the colour to develop, and also after the colour had been allowed to develop in the dark for about 48 hours.

The results are shown in Table 4.

~'~2'~37 Additive Background CI Dark Int~nsity 2 mins Developed Io control 83.0 69.6 63~7 (NH4)2S04 80.8 80.1 70.8 acetylacetone 83.0 76.6 67.3 cyclopentanone 83.3 73.8 66.3 cyclohexanone 83.3 74.3 66.6 10 ethylacetoacetate 83.3 76.1 68.7 From the above results it can be seen that the control in which no quenching agent has been added produces the best CI
values. This is because no quenching agent is present to desensitise the colour developer. However the level of 15 formaldehyde is unacceptable.

Whilst the sample treated with amononium sulphate had a low level of formaldehyde the CI values indicate that the colour developer has been desensitised to an unacceptable degree.

Claims (5)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:
1. A method for producing a self-cantained pressure sensitive copying material comprising the steps of coating a sheet material with a coating composition comprising a colour developer material, a formaldehyde-containing suspension of microcapsules containing a colour former solution and a compound having a .beta. dicarbonyl group selected from the group consisting of malonic acid, acety-lacetone, malonamide and diethyl malonate or a cyclic ketone which is added to the suspension of microcapsules in an amount effective to remove free formaldehyde from the suspension.
2. The method as claimed in claim 1 wherein said compound having the .beta. -dicarbonyl group is acetylacetone.
3. The method as claimed in claim 1 wherein said cyclic ketone is cyclohexanone or cyclopentanone.
4. The method as claimed in claim 1 wherein said compound having a .beta.-dicarbonyl group or said cyclic ketone is added to the microcapsule suspension in an amount of 1 to 2% by weight of the suspension.
5. A self-contained pressure sensitive copying material produced by a method as claimed in claim 1.
CA000463703A 1983-10-07 1984-09-20 Method for the removal of free formaldehyde from a formaldehyde-containing suspension of microcapsules Expired CA1224037A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB8326902 1983-10-07
GB838326902A GB8326902D0 (en) 1983-10-07 1983-10-07 Removal of formaldehyde from micro-capsules

Publications (1)

Publication Number Publication Date
CA1224037A true CA1224037A (en) 1987-07-14

Family

ID=10549844

Family Applications (1)

Application Number Title Priority Date Filing Date
CA000463703A Expired CA1224037A (en) 1983-10-07 1984-09-20 Method for the removal of free formaldehyde from a formaldehyde-containing suspension of microcapsules

Country Status (8)

Country Link
US (1) US4612556A (en)
EP (1) EP0138448B1 (en)
JP (1) JPS60102932A (en)
CA (1) CA1224037A (en)
DE (1) DE3472078D1 (en)
ES (1) ES8606133A1 (en)
FI (1) FI75506C (en)
GB (1) GB8326902D0 (en)

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GB8607689D0 (en) * 1986-03-27 1986-04-30 Wiggins Teape Group Ltd Imaged microcapsule-coated paper
GB8700765D0 (en) * 1987-01-14 1987-02-18 Wiggins Teape Group Ltd Laser apparatus
AT387976B (en) * 1987-08-05 1989-04-10 Vianova Kunstharz Ag METHOD FOR REDUCING FORMALDEHYDEMISSION IN ACID-HARDENING VARNISHES BASED ON ALKYD RESIN-URINE RESIN COMBINATIONS
GB8803560D0 (en) * 1988-02-16 1988-03-16 Wiggins Teape Group Ltd Laser apparatus for repetitively marking moving sheet
US4935149A (en) * 1989-01-12 1990-06-19 Calgon Corporation Low free formaldehyde melamine-formaldehyde detackifier and method of using
US5068279A (en) * 1989-01-12 1991-11-26 Calgon Corporation Low free formaldehyde melamine-formaldehyde detackifier and method of using
US5352495A (en) * 1989-02-16 1994-10-04 The Wiggins Teape Group Limited Treatment of a surface by laser energy
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US5795933A (en) * 1996-12-19 1998-08-18 The Dexter Corporation Waterborne coating compositions having ultra low formaldehyde concentration
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CN103173004B (en) * 2011-12-23 2014-12-03 万华化学(广东)有限公司 Aqueous polyurethane dispersion composition with formaldehyde reactivity as well as preparation method and application thereof
KR102492617B1 (en) 2015-04-14 2023-01-27 위테네 알베르뛰 프랑스 Phenolic resin composition for polyurethane cold-box and/or no-bake process and corresponding two-component binder system, use and process
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Also Published As

Publication number Publication date
EP0138448A3 (en) 1985-12-27
EP0138448A2 (en) 1985-04-24
FI843889L (en) 1985-04-08
DE3472078D1 (en) 1988-07-21
EP0138448B1 (en) 1988-06-15
FI843889A0 (en) 1984-10-03
ES8606133A1 (en) 1986-04-01
ES536509A0 (en) 1986-04-01
US4612556A (en) 1986-09-16
FI75506C (en) 1988-07-11
GB8326902D0 (en) 1983-11-09
JPS60102932A (en) 1985-06-07
FI75506B (en) 1988-03-31

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