FI70180B - MAERKREGISTRERINGSSYSTEM - Google Patents

Abstract

The invention relates to mark-recording systems, for example carbonless copying paper, in which a colourless chromogen is brought into contact with a chromogen-sensitizing agent in the presence of a liquid solvent for the chromogen, thereby producing a visible mark. In a system of the invention, the chromogen is a derivative of diphenylmethanol or diphenylmethylamine, the sensitizing agent is an acid clay, and the solvent comprises an aliphatic benzyl phthalate.

Description

NOTICE 70180 B 11 UTLÄGGNINGSSKRIFT OU

^ (45) i.iysi '^ cUy 4¾¾) (' Patent me 10 slat 15 03 1300 (51) Kv.lk//lnt.CI.* B k] M 5/12 FINLAND - FINLAND (21) Patenttihakemus - Patentansökning 7916 ^ 7 (22) Application date - Ansökningsdag ^ .b. 05.79 (FI) (23) Starting date - Giltighetsdag 2 ^ .05.79 (41) Has become public - Blivit offentlig 01.12.79

National Board of Patents and Registration Date of publication and publication. - 28.02.86

Patent- och registerstyrelsen 1 Ansökan utlagd och utl.skriften publicerad (32) (33) (31) Claim claimed - Begärd priority 31.05.78 England-England (GB) 25960/78 (71) Monsanto Europe SA, Avenue de Tervuren 270- 272, 1150 Brussels,

Belg i a-Belg i en (BE) (72) Pierre Jean Allart, Brussels, Claude Andre Guillaume, Jodoigne,

This invention relates to pressure sensitive character registration systems. The present invention relates to pressure sensitive character registration systems.

The best known form of pressure sensitive mark registration system is a so-called carbonless copy paper comprising a two-sheet system in which the lower surface of the top sheet has a coating of microcapsules of a colorless chromogenic solution, while the bottom (recipient) sheet has an absorbent top. When the topsheet is printed with the marking means, the microcapsules break locally, thus releasing the chromogenic solution from the contacted microcapsules to react with the sensitizer below and form colored indicia on the recipient sheet corresponding to the indicia printed on the topsheet.

A successful carbonless copy paper system must meet a number of criteria. For example, the 2 70180 characters on the recipient sheet must develop rapidly into a readable color intensity, and the readable character must be retained for as long as the sheet is to be retained. Whether different criteria are met depends on a number of factors, such as the nature of the chromogen, solvent and sensitizer, and many different materials have been proposed for each group. Chromogens that have been proposed include phthalide derivatives, for example, crystal violet lactone and malachite violet lactone, indole-substituted pyrometallitides, leukuramines, and diphenylmethane derivatives, such as Michler's hydrol. Solvents that have been proposed include hydrocarbons, for example petroleum fractions or synthetic hydrocarbons, such as hydrogenated terphenyls, halogenated hydrocarbons, for example chlorinated biphenyls, and esters, for example alkyl adipates and alkyl phthalates. The sensitizer is usually an acid clay, for example attapulgite or bentonite clay, or an acidic organic polymer, for example a phenol-aldehyde polymer or a partially or completely hydrolysed styrene-maleic anhydride or ethylene-maleic anhydride polymer.

Chromogens that are likely to be most frequently mentioned in the art are phthalide derivatives, especially crystal violet lactone. These chromogens are usually used in solution in a hydrocarbon-type solvent. One reason for this choice of solvent is that although phthalide color formers are soluble in, for example, esters, it is found that esters and certain other solvents with similar polarity to esters show too much tendency to compete with the chromogen in affinity for the sensitizer. no color development occurs. This is especially the case with certain acid clay sensitizers.

Certain chromogens that are diphenylmethane derivatives are subject to this restriction and can be used with solvents such as esters, which have the advantage over hydrocarbons that the chromogens are more soluble and have higher solubilities. The use of diphenylmethane derivatives, such as Michler's hydrol, as chromogens in pressure sensitive mark registration systems is described, for example, in British Patent No. 1,381,928 and U.S. Patent 4,000,087.

This invention relates to an improvement in the use of chromogens in pressure sensitive label registration systems which are diphenylmethane derivatives.

3,70180

The pressure-sensitive mark registration system according to the invention consists of (a) a sheet material (b) mark-forming components supported on the sheet material and arranged in a parallel but unreactive state, said components consisting of a chromogen of diphenylmethanol and diphenyl, produces a color from the chromogen when contacted with the chromogen in the presence of a liquid solvent for the chromogen consisting of aliphatic benzyl phthalate and (c) said solvent being supported on the sheet material but separated from the sensitizer by a physical barrier layer which can be broken by pressing the label.

Compared to solvents, for example xylene or di-butyl phthalates, which have hitherto been proposed for use with chromogens which are diphenylmethane derivatives, the use of the solvents of this invention results in improved fading time of labels on the recipient sheet during storage, especially if stored under conditions. due to the action of oxygen.

In the aliphatic benzyl phthalate useful in this invention, one of the carboxyl groups of the phthalate is esterified with an aliphatic group and the other with a benzyl group. For example, an aliphatic group may contain up to 24 carbon atoms and may have a straight or branched chain. It may be, for example, an alkyl group, for example ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, n-hexyl, isohexyl, n-octyl, 2-ethylhexyl -, desyl, tetradesyl or octadecyl group. Preferred alkyl groups contain 2 to 12 carbon atoms. Alternatively, the aliphatic group may be an alkoxyalkyl group or a group derived from an alkyl group by replacing more than one -C 1-4 group with the same number of oxygen atoms, and thus may be, for example, an ethoxyethyl or 3,6,9-trioxaundesyl group. A third possibility is that the aliphatic group is derived from an alkyl ester of a hydroxycarboxylic acid, e.g. a C 1-6 alkyl ester of glycolic acid, beta-hydroxypropionic acid or gamma-hydroxybutyric acid; 4,70180 or a hydroxyalkyl ester of an aliphatic carboxylic acid, wherein the hydroxyalkyl radical and the aliphatic carboxylic acid may each contain up to 12 carbon atoms. Examples of such aliphatic groups are butoxycarbonylmethyl, (2-ethylhexyloxy) carbonylmethyl, 2- (ethylcarbonyloxy) ethyl and 7- (2,6,6,8-tetramethyl-4-oxa-3-oxononyl).

As used herein, the term "benzyl" is intended to include both an unsubstituted benzyl group and a substituted benzyl group, especially an alkyl-substituted benzyl group.

The core of the benzyl group may contain, for example, up to three alkyl substituents, each of which is, for example, alkyl groups having up to four carbon atoms, for example methyl or ethyl groups; or one or both of the methylene hydrogen atoms of the benzyl group may be replaced by a similar alkyl group.

Typical examples of aliphatic benzyl phthalates useful in this invention include butyl-unsubstituted benzyl phthalates, e.g., n-butylbenzyl phthalate and isobutylbenzyl phthalate, 2,6-oxyethyl-phthalate-octyl benzyl phthalate, e.g., n-octyl benzyl phthalate; ) unsubstituted benzyl phthalate.

The solvents used in this invention may contain more than one aliphatic benzyl phthalate, for example mixtures of alkyl benzyl phthalates having a full range of alkyl group sizes, e.g. C 1 -C 4, C 1 -C 6 or C 8 -C 8 series. The solvents may optionally contain other components, for example dialkyl phthalates, such as dibutyl phthalate and dioctyl phthalates, and various hydrocarbons, for example C6-C12 alkylbenzenes, light petroleum or other petroleum fractions which are useful as diluents under certain conditions to reduce the viscosity of the solvent. The solvent preferably contains at least 50% by weight of aliphatic benzyl phthalate or a mixture of aliphatic benzyl phthalates. The weight ratios of aliphatic benzyl phthalate to diluent in the mixtures may vary, for example, from 50:50 to 90:10, for example 60:40, 70:30, 75:25 or 80:20. In order to rapidly develop the strength of the print, the solvent is preferably one having a viscosity between 5 and 15 cSt at 38 ° C.

The chromogenic concentration in the solution of the invention is generally of the same order of magnitude as 5,70180 for known solutions of chromogens which are derivatives of diphenylmethanol or diphenylacetylamine, e.g. 0.25 to 5%, in particular 0.4 to 4.0% by weight of the solution.

Chromogens that are particularly suitable for use in this invention include Michler's hydrol, i.e., bis (p-dimethylaminophenyl) methanol, its ethers, for example, Michler's hydrolyl methyl ether and Michler's hydrolyl benzyl ether, Michler's hydrol aromatic sulfone. and sulfin esters, for example Michler's hydrol p-toluene sulfinate and bis (p-dimethylaminophenyl) methylamine derivatives, for example N / bis (p-dimethylaminophenyl) methyl / morpholine.

Several encapsulation systems have been proposed to encapsulate a chromogen solution for use in carbonless copy paper, and capsule walls in such systems can generally be formed of either natural or systemic polymeric material. In the present invention, the wall or shell of the capsule is preferably made of a synthetic polymer, for example, a polyurethane resin, a urea-formaldehyde resin, a melamine-formaldehyde resin or a polyamide resin. The use of such resins as a shell-forming material in encapsulation is described, for example, in U.S. Patent No. 3,016,308, British Patent No. 989,264, and U.S. Patent No. 3,429,827. Such shells can be made significantly less permeable to the aliphatic benzyl phthalates used herein. in the invention than shells made of a natural polymeric material such as gelatin.

The acid clay used as a chromogen sensitizer in this invention may be any of those conventionally used for this purpose, such as bentonite and attapulgite. Various treatments, such as acid extraction or calcination, can be performed on naturally occurring clay prior to its use as a sensitizer.

The character registration system of the present invention can be manufactured according to well-known conventional procedures. Descriptions of methods for making both color-bearing paper and clay-coated recipient paper can be found in the literature.

Although a preferred embodiment of the present invention comprises a two-sheet system in which one sheet supports an acidic clay and the other sheet supports a registration fluid consisting of a chromium gene and a solvent, the invention is not limited to such systems. The only absolute requirement is that the chromogen and acid clay be kept in a separate or unreacted state until pressure is applied to the system and that by applying pressure, the chromogen and acid clay are brought into reactive contact. Thus, it is possible to keep the chromogen and acid clay present in a dry and unreacted state with a common carrier and keep the solvent alone supported on a separate sheet, releasing pressure on the solvent to release the mixture of chromogen and acidic material and promote local reaction and color development. Obviously, many other arrangements, structures, and ratios of solvent to label-forming materials with respect to their encapsulation and placement on backing sheets or tissues can be presented, and such arrangements are within the scope of this invention. For example, it is possible to coat a single paper or support member with all the components of this system to form a single independent unit that can be annotated by the movement of a plotter or other pressure generating device on the surface of the paper. Such papers are particularly useful for use in inkless registration instruments.

The solutions of the invention were evaluated by the following technique:

A 0.5% by weight solution of Michler's hydrol p-toluenesulfinate in a solvent was prepared. To evaluate the strength of the print, a plate engraved with a dot pattern was brushed with a sufficient amount of solution to obtain a layer 18 microns thick using a scraper blade. A sled-supported roll wrapped around a sheet of paper coated with an acid clay sensitizer was then slowly moved over a plate brushed with solution at constant pressure. The color developed on the paper. The paper was removed from the roll and the color intensity was measured using a Macbeth RD 514 reflectometer calibrated against an optical density of 0.07 units "perfect white" and an optical density of 1.78 units "perfect black" using the manufacturer's standard "perfect white" and "complete black" black "plate. After taking the initial reading, the paper was transferred to a cabinet at 75 ° C and 40% relative humidity. It was removed from time to time for new color intensity measurements.

To obtain the results shown in the table below, the color density of the butter 7 70180 was measured each time at 25 different points on the surface of the paper and the results were averaged.

The following abbreviations are used: DBP - dibutyl phthalate DOP - dioctyl phthalate BBP - butyl benzyl phthalate OBP - octyl benzyl phthalate TBP - 2,6,6,8-tetramethyl-4-oxa-3-oxonon-7-yl benzyl phthalate ALB - (C8-alkyl) benzene

Table 1 shows the results obtained using single-manufacturer clay-coated receiver sheets with the solvent each time a mixture of phthalate, either with ALB in a weight ratio of 7: 3 or with kerosene in a weight ratio of 8: 2.

table 1

Solvent Time (hours) 0367 22.5 25.5 1 DBP / ALB 7: 3 0.616 0.532 0.492 2 OBP (sample 1) / ALB 7: 3 0.628 0.648 0.577 3 OBP (sample 2) / ALB 7: 3 0.606 0.624 0.544 4 OBP (sample 3) / ALB 7: 3 0.600 0.635 0.566 5 TBP / ALB 7: 3 0.579 0.602 0.553 6 OBP (sample 1) / Light petroleum 8: 2 0.621 0.585 0.577 0.571 7 DBP / light kerosene 8: 2 0.601 0.568 0.519 0.472

A comparison of solvent 1 with solvents 2-5 or a comparison of solvent 6 with solvent 7 shows that the print strength deteriorates significantly more slowly when the phthalate is aliphatic benzyl phthalate than when the phthalate is dibutyl phthalate.

Table 2 shows the results obtained using clay-coated receiver sheets from another manufacturer.

8, o 7 01 80

Table 2

Solvent Time (hours) 0 3 5.5 7 22 25.5 29.5 31.5 8 DBP 0.720 0.545 0.436 0.388 9 BBP 0.671 0.621 0.565 0.489 10 DBP / kerosene 0.612 0.456 0.426 0.271 0.195 8: 2 11 OBP / kerosene 0.652 0.565 0.532 0.466 0.391 8: 2

The superiority of alkyl benzyl phthalates over dibutyl phthalate is seen when comparing solvent 9 to solvent 8 and solvent 11 to solvent 10.

Table 3 shows the results obtained using clay-coated receiver sheets from another manufacturer with the solvent each time a mixture of phthalate with ALB in a weight ratio of 7: 3.

Table 3

Phthalate Time (hours) 0 6.5 23 30 DBP 0.776 0.582 0.360 0.313 DOP 0.630 0.380 0.350 OBP (sample 1) 0.689 0.628 0.417 0.401 OBP (sample 2) 0.656 0.626 0.507 0.468 OBP (sample 3) 0.658 0.611 0.473 0.416 TBP 0.7 0.434 0.384 The color intensities are again seen to decrease more slowly when the solvent consists of aliphatic benzyl phthalate than when the solvent consists of dialkyl phthalate.

Claims (7)

70180 9 A pressure-sensitive rake registration system consisting of (a) a sheet material, (b) label-forming components supported on the sheet material and arranged in a parallel position but in an unreacted state, said components consisting of a cyanogen-diphenylmethanol or diphenylmethylamine-derived chromogen a sensitizer which produces a color from the chromogen when contacted with the chromogen in the presence of a liquid solvent for the chromogen, (c) said liquid solvent being supported on the sheet material but separated from the sensitizer by a physical barrier layer known as consists of aliphatic benzyl phthalate. A system according to claim 1, characterized in that the aliphatic group of the aliphatic benzyl phthalate is an alkyl group having up to 24 carbon atoms. System according to Claim 2, characterized in that the aliphatic benzyl phthalate is butyl-unsubstituted benzyl phthalate or octyl-unsubstituted benzyl phthalate. A system according to claim 1, characterized in that the aliphatic group of the aliphatic benzyl phthalate is derived from an alkyl ester of a hydroxycarboxylic acid or a hydroxy (C 1-4 alkyl) ester of an aliphatic C 1-4 alkyl acid. System according to Claim 4, characterized in that the aliphatic benzyl phthalate is 7- (2,6,6,8-tetramethyl-3-oxa-3-oxononyl) unsubstituted benzyl phthalate. The system according to claim 1, characterized in that the aliphatic group of the aliphatic benzyl phthalate is an alkyl group having 2 to 12 carbon atoms. System according to any one of Claims 1 to 5, characterized in that the solvent is a mixture of at least one aliphatic benzyl phthalate and a hydrocarbon diluent containing at least 50% by weight of aliphatic benzyl phthalate or phthalate.