CA1139561A - Pressure-sensitive recording paper - Google Patents
Pressure-sensitive recording paperInfo
- Publication number
- CA1139561A CA1139561A CA000354708A CA354708A CA1139561A CA 1139561 A CA1139561 A CA 1139561A CA 000354708 A CA000354708 A CA 000354708A CA 354708 A CA354708 A CA 354708A CA 1139561 A CA1139561 A CA 1139561A
- Authority
- CA
- Canada
- Prior art keywords
- pressure
- sensitive recording
- recording paper
- colour
- under
- 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
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
- B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
- B41M5/00—Duplicating or marking methods; Sheet materials for use therein
- B41M5/124—Duplicating 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
- B41M5/165—Duplicating 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
- B41M5/1655—Solvents
-
- Y—GENERAL 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
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S428/00—Stock material or miscellaneous articles
- Y10S428/914—Transfer or decalcomania
Abstract
PRESSURE-SENSITIVE RECORDING PAPER
ABSTRACT OF DISCLOSURE:
A pressure-sensitive recording paper exhibiting excellent properties even under severe environmental conditions such as high temperature and high humidity or low temperature is offered, the pressure-sensitive recording paper of the present invention includ-ing a sheet coated with microcapsules containing therein a solution of a colour former in 1-isopropylphenyl-2-phenylethane as a solvent
ABSTRACT OF DISCLOSURE:
A pressure-sensitive recording paper exhibiting excellent properties even under severe environmental conditions such as high temperature and high humidity or low temperature is offered, the pressure-sensitive recording paper of the present invention includ-ing a sheet coated with microcapsules containing therein a solution of a colour former in 1-isopropylphenyl-2-phenylethane as a solvent
Description
I~ACKG:ROU~ID F T~IE II~VENTION~
The present invention concerns an improved pressure-sensitive recording paper, and particularly concerns an improved pressure-sensitive recording paper which exhibits excellent pro-perties even under severe environmental conditions such as high am~ient temperature and high humidity or low ambient temperature.
Generally, pressure-sensitive recording paper is composed of (1) a sheet of paper having its back side coated with microcapsules formed by a solution of a colourless electron-donating substance (hereinafter referred to as a colour former) having a colour-forming reactivity in a solvent (hereinafter referred to as a CB paper) combined with another sheet of paper having its front side coated with a colour-developing substance (hereinaEter referred to as a developer) which can form a colour-ing product in reacting with the above-mentioned colour former (herelnafter referred to as a CF paper; (2) a sheet oE paper having its both sides coated with the above-mentioned micro-capsules and the above-mentioned developer, respectively (herein-after referred to as a CFB paper) combined with the above-mentioned 2Q CB paper and the above-mentioned CF paper; or (3) a sheet of paper having its one side coated together with the above-mentioned microcapsules and the above-mentioned developer. In either case of these pressure-sensitive recording papers, an artificial appli-cation of a pressure on the paper brea~s the microcapsules at the pressured part to bring the colour former into contact with the developer resulting in colour development.
.~
In the pressure-sensitive recording paper constituted as mentioned above, the matters which give an important influence on the quality of the pressure-sensitive recording paper are the solvent of the colour former included in the above-mentioned microcapsules and the wall material which forms the microcapsule.
Hitherto, the speci~ic properties required for the above-mentioned solvent have been as follows:
(1) it dissolves the colour former to a high concentra-tion,
The present invention concerns an improved pressure-sensitive recording paper, and particularly concerns an improved pressure-sensitive recording paper which exhibits excellent pro-perties even under severe environmental conditions such as high am~ient temperature and high humidity or low ambient temperature.
Generally, pressure-sensitive recording paper is composed of (1) a sheet of paper having its back side coated with microcapsules formed by a solution of a colourless electron-donating substance (hereinafter referred to as a colour former) having a colour-forming reactivity in a solvent (hereinafter referred to as a CB paper) combined with another sheet of paper having its front side coated with a colour-developing substance (hereinaEter referred to as a developer) which can form a colour-ing product in reacting with the above-mentioned colour former (herelnafter referred to as a CF paper; (2) a sheet oE paper having its both sides coated with the above-mentioned micro-capsules and the above-mentioned developer, respectively (herein-after referred to as a CFB paper) combined with the above-mentioned 2Q CB paper and the above-mentioned CF paper; or (3) a sheet of paper having its one side coated together with the above-mentioned microcapsules and the above-mentioned developer. In either case of these pressure-sensitive recording papers, an artificial appli-cation of a pressure on the paper brea~s the microcapsules at the pressured part to bring the colour former into contact with the developer resulting in colour development.
.~
In the pressure-sensitive recording paper constituted as mentioned above, the matters which give an important influence on the quality of the pressure-sensitive recording paper are the solvent of the colour former included in the above-mentioned microcapsules and the wall material which forms the microcapsule.
Hitherto, the speci~ic properties required for the above-mentioned solvent have been as follows:
(1) it dissolves the colour former to a high concentra-tion,
(2) when applied in the pressure-sensitive recording paper, the velocit~ of colour-development, the colour-density and the colour stability after colour-development are high,
(3) it is stable against light, heat and chemicals,
(4) lt is substantially odorless,
(5) it is harmless to human body,
(6) it has a sufficient biodegradability and accordingly, it does not cause environmental pollution.
On the other hand, uniformity and excellent mechanical strength are required for the wall material of the microcapsules, and the microcapsules are normally prepared by the so-called coacervation method.
As the wall material which fulfills the above-mentioned requisites and is easily subjected to microcapsulation, several high molecular substances have been offered, however, at present, gelatin is widely used as the most suitable wall material.
~owever, in recent years, the utilization of pressure-sensitive cording papers has come to propagate throughout the world and they have come to b~ used even-under a hot and humid climate or very cold climate.
Accordingly, during the period of transportation for the exporting the pressure-sensitive recording papers or the period of warehouse-storage of the papers in the above-mentioned regions of extreme climates, the chance of exposure of the pres~
sure-sensitive recording papers to severe environmental condition or the chance of usage under such severe environmental conditions lQ has been increased.
The term "severe environmental condi-tions" herein used means the so-called hot and humid environmental corditions of an ambient temperature of about 40 to 50C and of a relative humidity of higher than about 80%, and the cold environmental condition of an ambient temperature of lower than about 0C.
As an instance where the pressure-sensitive recording papers are exposed to the above-mentioned severe environmental conditions, the case in which the pressure-sensitive recording papers are left in the hot and humid environment in holds of a cargo boat for long time period during the transportation for the export and the case in which the pressure-sensitive recording papers are stored for long time in warehouses in a climatically hot and humid region can be mentioned. As an instance where the pressure-sensitive recording papers are used under the severe environmental conditions, a case in which the pressure-sensitive recording paper is used to register records in a cold climate in the open air such as at a gasoline stand can be mentioned.
In the case where the pressure-sensitive recording paper is left for a long time under the hot and humid environmental conditions, the solution of the colour former included in the microcapsules of the pressure-sensitive recording paper exude5 to outside of the capsule with a result of causing undesirable .
colour-development before the use of the paper and of damaging the paper by contamination to prevent the satisfactory colour-development in its proper use time. Such a damage might cause . a fatal problem that the so-dama~ed pressure-sensitive recording paper is no more to be offered to actual use.
: On the other hana, in the case where the pressure-sensitive recording paper is used in the above-mentioned very cold region, it takes a long period of time to develop a sufficiently visible colour and accordingly, the recording can not be read for a considerable time period and so there is a problem that the paper ~:~ is no more to be offered in actual use.
: However, hitherto, since the pressure-sensitive record-ing paper has not been propagated to the degree that it is often .
exposed to the above-mentioned severe environmental conditions or used in the above-mentioned se~ere environment, it has not been recognized at all that the pressure-sensitive recording paper should have maintained its excellent properties at its specific important requisite even under the above-mentioned severe ~L~3~
environmental conditions. Accordingly, there has never seen any literature on the pressure-sensitive recording paper which is able to keep the excellent properties even under the above-mentioned severe environmental conditions.
We, the inventors of the present invention, in considera-tion of the above-mentioned circumstances, have paid special atten-tion to the presumed fact that it will be very important to select the solvent in the microcapsules included in the pressure-sensitive recoxding paper in order to offer a pressure-sensitive recording paper which is able to maintain the excellent propexties even in the above-mentioned severe environmental conditions, and have carried out the examination. However, we have found that such a selection of the solvent which is able to fulfill the above-mentioned requisites (1) to (6) even in the above-mentloned severe environmental conditions is extremely difficult. The difficulty . would be due to the contradiction of the properties which shouldbe fulfilled by the solvent in the climatically hot and humid region and the properties which should be fulfilled by the same solvent in the very cold region.
2Q In these cixcumstances, according to our xesults on the examination of the publicly known solvents hitherto have been used in the conventional pressure-sensitive recording papers, we could not found any solvent which fulfills the above-mentioned requisites (1) to (6) in the same time in the above-mentioned severe environ-mental conditions.
However, on our examination on several compounds which _ 5 _ l~a~s~
have never been known as the solvent for the pressure-sensitive recording paper, quite surprisingly it was found that l-isopropyl-phenyl-2-phenylethane had a specific property to fulfill the above-mentioned requisites under the above-mentioned severe environmental conditions, that is, both under the climatically hot and humid environmental conditions and under the very cold environmental conditions of lower than 0C.
As the representative solvents hitherto practially used for fulfilling the above-mentioned requisites (1) to (6), the following members are possibly mentioned:
(a) diisopropylnaphthalene, . tb) isopropylbiphenyl, (c) hydrogenated terphenyl, (d) l-dimethylphenyl-l-phenylethane and (e) `ethylphenyl-phenylmethane.
-Among these solvents, (b), (d) and (e) are unstable : in cases where they are used in the pressure-sensitive recording papers under the hot and humid conditions, while (a) and (c) exhi.bit only a poor colour-development at a lower temperature than 0C, and accordingly, these solvents are not suitable as the solvent for use under the herein-mentioned severe environmental conditions in the pressure-sensitive recording paper.
For instance, US Patent No. 3 836 383 discloses a solvent for use as the solvent for the pressure-sensitive record-ing paper having the following structure resembling to the above-mentioned l-isopropylphenyl-2-phenylethane:
~ 2 2 ~ CH3 However, the pressure-sensitive recording paper using the disclosed solvent is not stable under the'hot and humid conditions, and moreover, the disclosed compound does not have a sufficient biodegradability.
Also, US Patent No. 3936 566 discloses a solvent for use in the pressure-sensitive recording paper having the following structure resembling to l-isopropylphenyl-2-phenylethane:
~)-CH- ~ -CH~
However, the:disclosed compound is also not so stable under hot and humid condition and has a low biodegradability, and accordingly it is not sufficient as a solvent for the pressure-~: sensitive recording paper.
And also,.Japanese.Patent Publication No. 49830/1971discloses a solvent for the pressure-sensitive recording paper having the following formula:
: CH3 / CH3 / \~-CH -CH -~3 / CH\CH3 However, the disclosed compound dissolves only poorly the colour former, and the colour-developing property of the 113~?5~
pressure-sensitive recording paper prepared by using this solvent is unfavorable in the very cold region.
As have been stated, since the hitherto publicly known solvents are not able to fulfill the above-mentioned requisites (1) to (6) under the severe climatic conditions herein mentioned, the pressure-sensitive recording papers prepared b~ any of these publicly known solvent are not possibly offered for practical uses under the above-mentioned severe environmental conditions.
Accordingly, the purpose of the present inventlon is to select and adopt, as the solvent, a compound which is able to fulfill the above-mentioned requisites ~1) to (6) even~ under the climatically hot and humid environmental conditions and under the climatically very cold environmental conditions r and ¦thereby to offer a pressure-sensitive recording paper which is stable and is possibly put to practical use even under the sevcre enviromnental conditions herein mentioned.
The other purposes of the present invention will be elucidated from the following descriptions:
~ .
BRIEF EXPLANATION OF DR~WINGS:
,, .~
The figure of the drawing illustrates the change of colour density of a pressure-sensitive recording paper prepared by the procedure described in Example 1 shown later on, at a low temperature of -5C in a graph.
~ 3L3~
DETAILED D~SCRIPTION OF THE INVFNTION:
The characteristic ~eature of the present invention is that, in the preparation of a pressure-sensitive recording paper, microcapsules containing a solut:ion of the colour former obtained by dissolving the colour former into l-isopropylphenyl-2-phenyl-ethane or a solvent containing the same are coated on a sheet of paper constituting the pressure-sensitive recording paper.
The structural formula and physical properties of l-isopropylphenyl-2-phenylethane for use as the solvent of the colour former in the present invention are shown - below for reference.
Structural formula: / CH3 : ~ -CH2-CH2- ~ \ CH3 Boiling point: 313 to 315C/760mmHg Specific gravity: 0.963 (dl5) Kinematic viscosity: 4.5 cst at 100F
In addition, the above-mentioned compouncl is synthesized, for instance, as follows:
(a) Benzene and 1,2-dichloroethane are brought into condensation in the presence of aluminum chloride as a catalyst to obtain 1,2-cliphenylethane, and the thus formed 1,2-diphenyl-ethane is subjected to propylation to form l-isopropylphenyl-2-phenylethane, or tb) benzene and cumen are brought into reaction with 1,2-dichloroethane in the presence or aluminum chloride as a catalyst to obtain l-lsopropylphenyl-2-phenylethane.
The thus obtained l-isopropylphenyl-2-phenylethane is a substantially odorless and colourless liquid.
Although l-isopropylphenyl-2-phenylethane for use in the present invention, as is shown in Examples later on, is able to fulfill the above-mentioned requisites (1~ to ~6) required ~or the solvent of the pressure-sensitive recording paper sufficiently even under the hot and humid environmen-tal conditions and also under -the very cold environmental conditions, it is considered to be remarkable from the scientific common knowledge that the above-mentioned compound has such a specific property.
According to the conventional scientific knowledge, the characteristic feature of chemical structure of a solvent which ~: acts stably in the pressure-sensitive recording paper under the hot and humid environmental conditions is said to be high in aliphaticity with a high molecular weight, and on the other hand, the characteristic feature of chemical structure of a solvent which gives a pressure-sensitive recording paper show-ing a favourable colour-developing property under the very cold environmental conditions is said to be high in aromaticity with a low molecular weight. That is, the character-istic feature of chemical structure of a solvent which gives a pressure-sensitive recording paper stable under the hot and humid environmental conditions and -that of a solvent : which gives a pressure-sensitive recording paper showing a -~ s~
favourable colour-developing property under the climatically very cold environmental conditions contradict each other. Accordingly, it should be considered that it :is actually almost impossible to presume and adopt a chemical compound for a pressure-sensitive recording paper which maintains its excellent quality under both conditions, from the chemical structure.
Although, in the present invention, it is most preferable to use l-isopropylphenyl-2-phenylethane alone, as a solvent, it may be used after mixing with another solvent unless its specific properties are not disturbed.
In addition, since 1-isopropylphenyl-2-phenylethane is excellent in dissolving various colour formers for use in the ; pressure sensitive recording paper, the colour former for use in the present invention possibly includes, for instance, benzoyl ; leucomethylene blue (BLMB), crystal violet lactone (CVL), mala-chite green lactone and diaminofluorane derivatives such as 3-dialkylamino-7-dialkylaminofluorane, etc.
Moreover, in the present invention, as a developer, those hitherto been used, for instance, acid clay, ~20 phenol resin, derivatives of salicylic salts, etc. are possibly used.
Examples shown below are the concrete exemplification of the preparation of the pressure-sensitive recording paper according to the present invention and the improved effectiveness of the above-mentioned pressure-sensitive recording paper.
Accordingly, it will be understood that the scope of the present invention is not restricted within Examples.
Example 1:
Synthesis of l-isopr_pylphenyl-2-phenylethane:
In a separable flaks, 5 mols of benzene, 5 mols of cumen and 0.5 mol of aluminum chloride as a catalyst are intro-duced, and after heating the flask to a temperature of 70C in a warm water bath, 2 mols of 1,2-dichloroethane were added to the mixture drop-wise under agitation while removing the evolving gaseous hydrogen chloride and the reaction was continued for 3 hours. After the reaction was over, and after separating the reaction product from the catalyst, the product was washed with water and subjected to vacuum distillation to obta n colourless 1-isopropylphenyl-2-phenylethane. The properties of the thus obtained product were:
Boiling point 313 to 315C/760mmHg, Specific gravity: 0.963 (dl45), and Kinematic viscosity: 4.5 cst/100F
Preparation of microcapsules:
Into 150 g of the thus obtained 1-isopropylphenyl-2-phenylethane, 2.7 g of crystal violet lactone and 1.8 g of leucomethylene blue were dissolved, and the solution was added to an aqueous solution of 30 g of gelatin in 270 g of water to be emulsified, and then an aqueous 30 g of gum arabic solution in 270 g of water~was added to the above-mentioned emulsified solu-tion while maintaining the temperature of the mixture at 50C
under agitation. In the next place, using an aqueous 50% acetic acid solution, the pH of the above-mentioned mixture was slowly reduced to 4.4 to cause a coacervation and by cooling the temperature of the mixture to 10C the membrane o~ the thus formed microcapsules was solidified, and 20 ml of an aqueous 25%
solution of glutaraldehyde were added to the liquid including the microcapsules. The membrane of the microcapsules was further solidified by making the p~ of the mixture to be 9 with the addition of an aqueous 10% solution of sodium hydroxide to make the capsulation completed.
Preparation of a pressure-sensitive recording paper:
The thus obtained microcapsules were coated on one side of a weighed sheet of paper of 45 g/m at a rate of dried material of 5 g/m to obtain a CB paper, and it was combined with a CF
paper prepared by the conventional method to prepare a pressure-sensitive recording paper.
Example 2:
The present Example shows the results of examination carried out on the pressure-sensitive recording paper according to the present lnvention under the hot and humid conditions.
After leaving a pressure-sensitive recording paper prepared by the procedures described in Example 1 in a cabinet maintained at a constant temperature of 40C and at a constant relative humidity of 90% for 16 hours, the paper was made to develop a colour by subjecting the paper to callender-rolls and the colour density was determined by a~refraction colour densitometer (manufactured by MacBeth Company).
~3~
In parallel, another pressure-sensitive recording paper prepared by the same procedures as described in Example 1 and left in an atmosphere of temperature of 15C and a relative humidity of 65% for 16 hours was made to develop a colour by the same procedures as above, and its colour density was determined as above. Then, the percentage of the colour density of the pressure-sensitive recording paper left in the hot and humid con-ditions described above to the colour density of the latter pressure-sensitive recording paper left in the atmosphere of temperature of 15C and a relative humidity of 65~ for 16 hours (as the standard) was obtained by calculation~ It was 70~. From this percentage, it is recognizable that the pressure-sensitive recording paper prepared in Example 1 did not show considerable reduction of quality even under the above-mentioned severe environmental conditions, and accordingly is stable enough.
Example 3:
; The present example shows the velocity of colour : development of the pressure-sensitive recording paper according to the present invention under very cold climatic environmental 2Q conditions.
A sheet of the pressure-sensitive recording paper prepared by the procedures described in Example 1 was subjected to the procedure of calender-rolling to develop a colour at an ordinary temperature, and the colour density of the thus treated pressure-sensitive recording paper was determined by a refractive , ~3~
.
colour densitometer ~anufactured by MACBETH Company) and the determined value, A, was used as a standard.
Meanwhile, another sheet of the same paper as above was subjected to the same procedure as above, however, in a room maintained at a temperature`of -5C. Its colour density was determined as above to be B.
The percentage of B to A, i.e., (B/A) x 100, was utilized to express the velocity of colour development of the paper at a temperature of -5C. The results are shown in the lQ annexed drawing.
As is seen in the drawing, the velocity of colour development of the pressure sensitive recording paper prepared by the procedures in Example 1 at a temperature, for instance, of -5C after 30 sec was 70%, showing the small effect under the low temperature of -5C. The results are shown in the attached figure. As is seen in the results, the pressure-sensitive recording paper of the present invention gives a clear colour development and is stable even at a low temperature.
Example 4:
The present example shows the results of examination on the biodegradability of 1-isopropylphenyl-2-phenylethane for use in the present invention.
In a 300 ml-conical flask, 1-isopropylphenyl-2-phenyl-ethane prepared by the procedures described in Example 1 and an 1~ i6~ ~
activated sludge were introduced together with a culture medium so as to make the concentrations of the two substances at 200 and 100 ppm, respectively to the medium, and the sludge was cultured for 2 weeks under shakiny. After -the cultivation, the extract of the cultured broth with a solvent was subjected to gaschromatography to determine the rate of biodegradation of l-isopropylphenyl-2-phenylethane. The result showed that 1-isopropylphenyl-~-phenylethane remained as small as 15% of the originally introduced amount, that is, the biodegradability of lQ the compound was high as ~5 %.
: . Example 5-;: The present example shows the results of examination on the stability of the pressure-sensitive recording paper according ~: ~ to the present~invention under climatically hot and low-humid ~:~ : environmental conditions.
~;~ A pressure-sensitive recording paper prepared according to the procedures described in Example 1 was left for 16 hours in a dryer kept at a constant temperature of 105C. The thus treated pressure-sensitive recording paper was successively sub-jected to colour development according to the procedures des~
: cribed in Example 2~and its colour density was compared ~ith the standard colour density of another pressure-sensitive record-: ing paper prepared by the same procedures as above, then kept for the same period in a normal environment at a room temperature and ~ ~3~
subject to colour development. The colour density of the former was 97~ of the latter. The result shows that the pressure-sensitive recording paper according to the present invention is stable even under the severe environmental conditions of hot and low-humid.
In the next place, the results of examination on the stability of the publicly known solvents for use in the pressure-sensitive recording papers under the severe environmental condi-tions are shown in the following Comparative Examples:
Comparative Example 1:
A pressure-sensitive recording paper was prepared accord-ing to the same procedures as described in Example 1, except for using isopropylbiphenyl instead of l-isopropylphenyl-2-phenyl-ethane. And the stability of the thus prepared pressure-sensitive recording paper under the climatically hot and humid conditions was examined by the same procedure as described in Example 2.
The result, that is, the colour density of the paper of Comparative Example l was only 11% of the standard colour density. From the result, it is seen that the pressure-sensitive recording paper prepared by using isopropylbiphenyl has almost lost its colour-developing capability under the hot and humid environmental conditions and the paper is not to be put to practical use.
Comparative Example 2:
A pressure-sensitive recording paper was prepared by the same procedures as have been described in Example 1, except for ~3~
using l-diethylphenyl-l-phenylethane instead of l-isopropylphenyl-2-phenylethane. The stability of the thus prepared pressure-sensitive recording paper under climatically hot and humid condi-tions was examined by the procedures described in Example 2. The result of examination showed that the colour density of the pres-sure-sensitive recording paper of the present Comparative Example 2 was only 16% of the standard colour density.
That i9, the pressure-sensitive recording paper prepared by using l-diethylphenyl-l-phenylethane is unstable under the climatically hot and humid environmental conditions and is not to be put to practicaI use.
Comparative Example 3:
A pressure-sens1tive recording paper was prepared by the same procedures as have been described in Example 1 r except for using ethylphenyl-phenylmethane instead of l-isopropylphenyl-2-phenylethane. The stability of the thus prepared pressure-sensitive recording paper under climatically hot and humid envi-ronmental conditions was examined by the procedures described in Example 2. The results showed that the colour density of the thus prepared pressure-sensitive recording paper was only 11~ of the standard colour density.
That is, the pressure-sensitive recording paper pre-pared by using ethylphenyl~phenylmethane is unstable under the hot and humid environmental conditions and is not to be put to practical use.
Comparative Example 4:
A pressure-sensitive recording paper was prepared by the same procedures as have been described in Example 1, except for using hydrogenated terphenyl instead of l-isopropylphenyl-2-phenylethane. The colour-developing property of -the thus prepared pressure-sensitive recording paper under the very cold environ-mental conditions was examined by the procedures described in Example 3. As a result, it was found that no clearly recognizable colour-development was observed even after 30 sec of the colour developing treatment of the thus prepared pressure-sensitive recording paper, and accordingly, it was found that such a record-ing paper could not be put to practical use under the very cold environmental conditions.
Comparative Example 5:
A pressure-sensitive recording paper was prepared by the same procedures as have been described in Example 1, except for using di-isopropylnaphthalene instead of l-isopropylphenyl-2-phenylethane. The colour-development property of the thus pre-pared pressure-sensitive recording paper under the very cold ~20 environmental conditions was examlned by the procedure described in Example 3. As a result, the colour density of the 'hus pre-pared pressure-sensitive recording paper was only 12% of the standard colour density after 30 sec of the colour-developlng treatment and it was found that such a paper is not to be put to practical use under the very cold environmental conditions.
~ s~ I
Comparative Example 6:
A pressure-sensitive recording paper was prepared by the same procedures as have been descrihed in Example 1, except Eor using 1,2-ditolylethane instead of 1-isopropylphenyl-2-phenyl-ethane. The stability of the thus prepared pressure-sensitive recording paper under the hot and humid environmental conditions was examined by the procedures described in Example 2. As a result, the thus prepared pressure-sensitive recording paper showed a colour density of only 11% of the standard colour density, the fact meaning that the stability of the thus prepared pressure-sensitive recording paper is very poor.
In another experiment, the biodegradabil'ty of 1,2-ditolylethane was determined by the same procedures as have been described in Example 4. As a result, the rate of biodegradability of 1,2-ditolylethane was only 28%.
Comparative Example 7:
A pressure-sensitive recording paper was prepared by the same procedures as have been described in Example 1, except for using 1,2-dicumylethane instead of 1-isopropylphenyl-2-phenyl-ethane. The colour-developing property of the thus prepared pressure~sensitlve recording paper under the very cold environ-mental conditions was examined by the procedures described in Example 3. As a result, the colour density of the thus prepared pressure-sensltive recording paper was only 10% of the standard colour density after 30 sec of the colour-developing treatment.
In another examination, the biodegradability of ~ s~ l 1,2-dicumylethane was determined by the procedures described i.n Example 4. -~he result showed that the biodegradability of 1,2-dicumylethane was found to be only 12%.
Comparative Example 8:
A pressure-sensitive recording paper was prepared by the same procedures as have been described in Example 1, except for using l-isopropylphenyl-l-phenylethane instead of l-isopropyl-phenyl-2-phenylethane as the solvent. The stability of the thus prepared pressure-sensitive recording paper under the hot and humid environmental conditions was examined by the procedures described in Example 2. It was found that the colour density of the thus prepared pressure-sensitive recording paper was 48% of the standard colour density. In another examination on the stability of the recording paper under the hot and low-humid environmental conditions by the procedures described in Example 5, the colour density of the recordiny paper was only 50% of the standard colour density and accordingly, its stability under the above-mentioned environmental conditions was poor. In the sepa-rate examination in which the biodegradability of l-isopropyl-phenyl-l-phenylethane was determined by the procedures described in Example 4, the biodeyradability of this solvent was only 16%.
As will be understood from the above-mentioned results, the pressure-sensitive recording paper of Comparative Example 8 is poor n pr ticabillty under the severe environmental conditions.
On the other hand, uniformity and excellent mechanical strength are required for the wall material of the microcapsules, and the microcapsules are normally prepared by the so-called coacervation method.
As the wall material which fulfills the above-mentioned requisites and is easily subjected to microcapsulation, several high molecular substances have been offered, however, at present, gelatin is widely used as the most suitable wall material.
~owever, in recent years, the utilization of pressure-sensitive cording papers has come to propagate throughout the world and they have come to b~ used even-under a hot and humid climate or very cold climate.
Accordingly, during the period of transportation for the exporting the pressure-sensitive recording papers or the period of warehouse-storage of the papers in the above-mentioned regions of extreme climates, the chance of exposure of the pres~
sure-sensitive recording papers to severe environmental condition or the chance of usage under such severe environmental conditions lQ has been increased.
The term "severe environmental condi-tions" herein used means the so-called hot and humid environmental corditions of an ambient temperature of about 40 to 50C and of a relative humidity of higher than about 80%, and the cold environmental condition of an ambient temperature of lower than about 0C.
As an instance where the pressure-sensitive recording papers are exposed to the above-mentioned severe environmental conditions, the case in which the pressure-sensitive recording papers are left in the hot and humid environment in holds of a cargo boat for long time period during the transportation for the export and the case in which the pressure-sensitive recording papers are stored for long time in warehouses in a climatically hot and humid region can be mentioned. As an instance where the pressure-sensitive recording papers are used under the severe environmental conditions, a case in which the pressure-sensitive recording paper is used to register records in a cold climate in the open air such as at a gasoline stand can be mentioned.
In the case where the pressure-sensitive recording paper is left for a long time under the hot and humid environmental conditions, the solution of the colour former included in the microcapsules of the pressure-sensitive recording paper exude5 to outside of the capsule with a result of causing undesirable .
colour-development before the use of the paper and of damaging the paper by contamination to prevent the satisfactory colour-development in its proper use time. Such a damage might cause . a fatal problem that the so-dama~ed pressure-sensitive recording paper is no more to be offered to actual use.
: On the other hana, in the case where the pressure-sensitive recording paper is used in the above-mentioned very cold region, it takes a long period of time to develop a sufficiently visible colour and accordingly, the recording can not be read for a considerable time period and so there is a problem that the paper ~:~ is no more to be offered in actual use.
: However, hitherto, since the pressure-sensitive record-ing paper has not been propagated to the degree that it is often .
exposed to the above-mentioned severe environmental conditions or used in the above-mentioned se~ere environment, it has not been recognized at all that the pressure-sensitive recording paper should have maintained its excellent properties at its specific important requisite even under the above-mentioned severe ~L~3~
environmental conditions. Accordingly, there has never seen any literature on the pressure-sensitive recording paper which is able to keep the excellent properties even under the above-mentioned severe environmental conditions.
We, the inventors of the present invention, in considera-tion of the above-mentioned circumstances, have paid special atten-tion to the presumed fact that it will be very important to select the solvent in the microcapsules included in the pressure-sensitive recoxding paper in order to offer a pressure-sensitive recording paper which is able to maintain the excellent propexties even in the above-mentioned severe environmental conditions, and have carried out the examination. However, we have found that such a selection of the solvent which is able to fulfill the above-mentioned requisites (1) to (6) even in the above-mentloned severe environmental conditions is extremely difficult. The difficulty . would be due to the contradiction of the properties which shouldbe fulfilled by the solvent in the climatically hot and humid region and the properties which should be fulfilled by the same solvent in the very cold region.
2Q In these cixcumstances, according to our xesults on the examination of the publicly known solvents hitherto have been used in the conventional pressure-sensitive recording papers, we could not found any solvent which fulfills the above-mentioned requisites (1) to (6) in the same time in the above-mentioned severe environ-mental conditions.
However, on our examination on several compounds which _ 5 _ l~a~s~
have never been known as the solvent for the pressure-sensitive recording paper, quite surprisingly it was found that l-isopropyl-phenyl-2-phenylethane had a specific property to fulfill the above-mentioned requisites under the above-mentioned severe environmental conditions, that is, both under the climatically hot and humid environmental conditions and under the very cold environmental conditions of lower than 0C.
As the representative solvents hitherto practially used for fulfilling the above-mentioned requisites (1) to (6), the following members are possibly mentioned:
(a) diisopropylnaphthalene, . tb) isopropylbiphenyl, (c) hydrogenated terphenyl, (d) l-dimethylphenyl-l-phenylethane and (e) `ethylphenyl-phenylmethane.
-Among these solvents, (b), (d) and (e) are unstable : in cases where they are used in the pressure-sensitive recording papers under the hot and humid conditions, while (a) and (c) exhi.bit only a poor colour-development at a lower temperature than 0C, and accordingly, these solvents are not suitable as the solvent for use under the herein-mentioned severe environmental conditions in the pressure-sensitive recording paper.
For instance, US Patent No. 3 836 383 discloses a solvent for use as the solvent for the pressure-sensitive record-ing paper having the following structure resembling to the above-mentioned l-isopropylphenyl-2-phenylethane:
~ 2 2 ~ CH3 However, the pressure-sensitive recording paper using the disclosed solvent is not stable under the'hot and humid conditions, and moreover, the disclosed compound does not have a sufficient biodegradability.
Also, US Patent No. 3936 566 discloses a solvent for use in the pressure-sensitive recording paper having the following structure resembling to l-isopropylphenyl-2-phenylethane:
~)-CH- ~ -CH~
However, the:disclosed compound is also not so stable under hot and humid condition and has a low biodegradability, and accordingly it is not sufficient as a solvent for the pressure-~: sensitive recording paper.
And also,.Japanese.Patent Publication No. 49830/1971discloses a solvent for the pressure-sensitive recording paper having the following formula:
: CH3 / CH3 / \~-CH -CH -~3 / CH\CH3 However, the disclosed compound dissolves only poorly the colour former, and the colour-developing property of the 113~?5~
pressure-sensitive recording paper prepared by using this solvent is unfavorable in the very cold region.
As have been stated, since the hitherto publicly known solvents are not able to fulfill the above-mentioned requisites (1) to (6) under the severe climatic conditions herein mentioned, the pressure-sensitive recording papers prepared b~ any of these publicly known solvent are not possibly offered for practical uses under the above-mentioned severe environmental conditions.
Accordingly, the purpose of the present inventlon is to select and adopt, as the solvent, a compound which is able to fulfill the above-mentioned requisites ~1) to (6) even~ under the climatically hot and humid environmental conditions and under the climatically very cold environmental conditions r and ¦thereby to offer a pressure-sensitive recording paper which is stable and is possibly put to practical use even under the sevcre enviromnental conditions herein mentioned.
The other purposes of the present invention will be elucidated from the following descriptions:
~ .
BRIEF EXPLANATION OF DR~WINGS:
,, .~
The figure of the drawing illustrates the change of colour density of a pressure-sensitive recording paper prepared by the procedure described in Example 1 shown later on, at a low temperature of -5C in a graph.
~ 3L3~
DETAILED D~SCRIPTION OF THE INVFNTION:
The characteristic ~eature of the present invention is that, in the preparation of a pressure-sensitive recording paper, microcapsules containing a solut:ion of the colour former obtained by dissolving the colour former into l-isopropylphenyl-2-phenyl-ethane or a solvent containing the same are coated on a sheet of paper constituting the pressure-sensitive recording paper.
The structural formula and physical properties of l-isopropylphenyl-2-phenylethane for use as the solvent of the colour former in the present invention are shown - below for reference.
Structural formula: / CH3 : ~ -CH2-CH2- ~ \ CH3 Boiling point: 313 to 315C/760mmHg Specific gravity: 0.963 (dl5) Kinematic viscosity: 4.5 cst at 100F
In addition, the above-mentioned compouncl is synthesized, for instance, as follows:
(a) Benzene and 1,2-dichloroethane are brought into condensation in the presence of aluminum chloride as a catalyst to obtain 1,2-cliphenylethane, and the thus formed 1,2-diphenyl-ethane is subjected to propylation to form l-isopropylphenyl-2-phenylethane, or tb) benzene and cumen are brought into reaction with 1,2-dichloroethane in the presence or aluminum chloride as a catalyst to obtain l-lsopropylphenyl-2-phenylethane.
The thus obtained l-isopropylphenyl-2-phenylethane is a substantially odorless and colourless liquid.
Although l-isopropylphenyl-2-phenylethane for use in the present invention, as is shown in Examples later on, is able to fulfill the above-mentioned requisites (1~ to ~6) required ~or the solvent of the pressure-sensitive recording paper sufficiently even under the hot and humid environmen-tal conditions and also under -the very cold environmental conditions, it is considered to be remarkable from the scientific common knowledge that the above-mentioned compound has such a specific property.
According to the conventional scientific knowledge, the characteristic feature of chemical structure of a solvent which ~: acts stably in the pressure-sensitive recording paper under the hot and humid environmental conditions is said to be high in aliphaticity with a high molecular weight, and on the other hand, the characteristic feature of chemical structure of a solvent which gives a pressure-sensitive recording paper show-ing a favourable colour-developing property under the very cold environmental conditions is said to be high in aromaticity with a low molecular weight. That is, the character-istic feature of chemical structure of a solvent which gives a pressure-sensitive recording paper stable under the hot and humid environmental conditions and -that of a solvent : which gives a pressure-sensitive recording paper showing a -~ s~
favourable colour-developing property under the climatically very cold environmental conditions contradict each other. Accordingly, it should be considered that it :is actually almost impossible to presume and adopt a chemical compound for a pressure-sensitive recording paper which maintains its excellent quality under both conditions, from the chemical structure.
Although, in the present invention, it is most preferable to use l-isopropylphenyl-2-phenylethane alone, as a solvent, it may be used after mixing with another solvent unless its specific properties are not disturbed.
In addition, since 1-isopropylphenyl-2-phenylethane is excellent in dissolving various colour formers for use in the ; pressure sensitive recording paper, the colour former for use in the present invention possibly includes, for instance, benzoyl ; leucomethylene blue (BLMB), crystal violet lactone (CVL), mala-chite green lactone and diaminofluorane derivatives such as 3-dialkylamino-7-dialkylaminofluorane, etc.
Moreover, in the present invention, as a developer, those hitherto been used, for instance, acid clay, ~20 phenol resin, derivatives of salicylic salts, etc. are possibly used.
Examples shown below are the concrete exemplification of the preparation of the pressure-sensitive recording paper according to the present invention and the improved effectiveness of the above-mentioned pressure-sensitive recording paper.
Accordingly, it will be understood that the scope of the present invention is not restricted within Examples.
Example 1:
Synthesis of l-isopr_pylphenyl-2-phenylethane:
In a separable flaks, 5 mols of benzene, 5 mols of cumen and 0.5 mol of aluminum chloride as a catalyst are intro-duced, and after heating the flask to a temperature of 70C in a warm water bath, 2 mols of 1,2-dichloroethane were added to the mixture drop-wise under agitation while removing the evolving gaseous hydrogen chloride and the reaction was continued for 3 hours. After the reaction was over, and after separating the reaction product from the catalyst, the product was washed with water and subjected to vacuum distillation to obta n colourless 1-isopropylphenyl-2-phenylethane. The properties of the thus obtained product were:
Boiling point 313 to 315C/760mmHg, Specific gravity: 0.963 (dl45), and Kinematic viscosity: 4.5 cst/100F
Preparation of microcapsules:
Into 150 g of the thus obtained 1-isopropylphenyl-2-phenylethane, 2.7 g of crystal violet lactone and 1.8 g of leucomethylene blue were dissolved, and the solution was added to an aqueous solution of 30 g of gelatin in 270 g of water to be emulsified, and then an aqueous 30 g of gum arabic solution in 270 g of water~was added to the above-mentioned emulsified solu-tion while maintaining the temperature of the mixture at 50C
under agitation. In the next place, using an aqueous 50% acetic acid solution, the pH of the above-mentioned mixture was slowly reduced to 4.4 to cause a coacervation and by cooling the temperature of the mixture to 10C the membrane o~ the thus formed microcapsules was solidified, and 20 ml of an aqueous 25%
solution of glutaraldehyde were added to the liquid including the microcapsules. The membrane of the microcapsules was further solidified by making the p~ of the mixture to be 9 with the addition of an aqueous 10% solution of sodium hydroxide to make the capsulation completed.
Preparation of a pressure-sensitive recording paper:
The thus obtained microcapsules were coated on one side of a weighed sheet of paper of 45 g/m at a rate of dried material of 5 g/m to obtain a CB paper, and it was combined with a CF
paper prepared by the conventional method to prepare a pressure-sensitive recording paper.
Example 2:
The present Example shows the results of examination carried out on the pressure-sensitive recording paper according to the present lnvention under the hot and humid conditions.
After leaving a pressure-sensitive recording paper prepared by the procedures described in Example 1 in a cabinet maintained at a constant temperature of 40C and at a constant relative humidity of 90% for 16 hours, the paper was made to develop a colour by subjecting the paper to callender-rolls and the colour density was determined by a~refraction colour densitometer (manufactured by MacBeth Company).
~3~
In parallel, another pressure-sensitive recording paper prepared by the same procedures as described in Example 1 and left in an atmosphere of temperature of 15C and a relative humidity of 65% for 16 hours was made to develop a colour by the same procedures as above, and its colour density was determined as above. Then, the percentage of the colour density of the pressure-sensitive recording paper left in the hot and humid con-ditions described above to the colour density of the latter pressure-sensitive recording paper left in the atmosphere of temperature of 15C and a relative humidity of 65~ for 16 hours (as the standard) was obtained by calculation~ It was 70~. From this percentage, it is recognizable that the pressure-sensitive recording paper prepared in Example 1 did not show considerable reduction of quality even under the above-mentioned severe environmental conditions, and accordingly is stable enough.
Example 3:
; The present example shows the velocity of colour : development of the pressure-sensitive recording paper according to the present invention under very cold climatic environmental 2Q conditions.
A sheet of the pressure-sensitive recording paper prepared by the procedures described in Example 1 was subjected to the procedure of calender-rolling to develop a colour at an ordinary temperature, and the colour density of the thus treated pressure-sensitive recording paper was determined by a refractive , ~3~
.
colour densitometer ~anufactured by MACBETH Company) and the determined value, A, was used as a standard.
Meanwhile, another sheet of the same paper as above was subjected to the same procedure as above, however, in a room maintained at a temperature`of -5C. Its colour density was determined as above to be B.
The percentage of B to A, i.e., (B/A) x 100, was utilized to express the velocity of colour development of the paper at a temperature of -5C. The results are shown in the lQ annexed drawing.
As is seen in the drawing, the velocity of colour development of the pressure sensitive recording paper prepared by the procedures in Example 1 at a temperature, for instance, of -5C after 30 sec was 70%, showing the small effect under the low temperature of -5C. The results are shown in the attached figure. As is seen in the results, the pressure-sensitive recording paper of the present invention gives a clear colour development and is stable even at a low temperature.
Example 4:
The present example shows the results of examination on the biodegradability of 1-isopropylphenyl-2-phenylethane for use in the present invention.
In a 300 ml-conical flask, 1-isopropylphenyl-2-phenyl-ethane prepared by the procedures described in Example 1 and an 1~ i6~ ~
activated sludge were introduced together with a culture medium so as to make the concentrations of the two substances at 200 and 100 ppm, respectively to the medium, and the sludge was cultured for 2 weeks under shakiny. After -the cultivation, the extract of the cultured broth with a solvent was subjected to gaschromatography to determine the rate of biodegradation of l-isopropylphenyl-2-phenylethane. The result showed that 1-isopropylphenyl-~-phenylethane remained as small as 15% of the originally introduced amount, that is, the biodegradability of lQ the compound was high as ~5 %.
: . Example 5-;: The present example shows the results of examination on the stability of the pressure-sensitive recording paper according ~: ~ to the present~invention under climatically hot and low-humid ~:~ : environmental conditions.
~;~ A pressure-sensitive recording paper prepared according to the procedures described in Example 1 was left for 16 hours in a dryer kept at a constant temperature of 105C. The thus treated pressure-sensitive recording paper was successively sub-jected to colour development according to the procedures des~
: cribed in Example 2~and its colour density was compared ~ith the standard colour density of another pressure-sensitive record-: ing paper prepared by the same procedures as above, then kept for the same period in a normal environment at a room temperature and ~ ~3~
subject to colour development. The colour density of the former was 97~ of the latter. The result shows that the pressure-sensitive recording paper according to the present invention is stable even under the severe environmental conditions of hot and low-humid.
In the next place, the results of examination on the stability of the publicly known solvents for use in the pressure-sensitive recording papers under the severe environmental condi-tions are shown in the following Comparative Examples:
Comparative Example 1:
A pressure-sensitive recording paper was prepared accord-ing to the same procedures as described in Example 1, except for using isopropylbiphenyl instead of l-isopropylphenyl-2-phenyl-ethane. And the stability of the thus prepared pressure-sensitive recording paper under the climatically hot and humid conditions was examined by the same procedure as described in Example 2.
The result, that is, the colour density of the paper of Comparative Example l was only 11% of the standard colour density. From the result, it is seen that the pressure-sensitive recording paper prepared by using isopropylbiphenyl has almost lost its colour-developing capability under the hot and humid environmental conditions and the paper is not to be put to practical use.
Comparative Example 2:
A pressure-sensitive recording paper was prepared by the same procedures as have been described in Example 1, except for ~3~
using l-diethylphenyl-l-phenylethane instead of l-isopropylphenyl-2-phenylethane. The stability of the thus prepared pressure-sensitive recording paper under climatically hot and humid condi-tions was examined by the procedures described in Example 2. The result of examination showed that the colour density of the pres-sure-sensitive recording paper of the present Comparative Example 2 was only 16% of the standard colour density.
That i9, the pressure-sensitive recording paper prepared by using l-diethylphenyl-l-phenylethane is unstable under the climatically hot and humid environmental conditions and is not to be put to practicaI use.
Comparative Example 3:
A pressure-sens1tive recording paper was prepared by the same procedures as have been described in Example 1 r except for using ethylphenyl-phenylmethane instead of l-isopropylphenyl-2-phenylethane. The stability of the thus prepared pressure-sensitive recording paper under climatically hot and humid envi-ronmental conditions was examined by the procedures described in Example 2. The results showed that the colour density of the thus prepared pressure-sensitive recording paper was only 11~ of the standard colour density.
That is, the pressure-sensitive recording paper pre-pared by using ethylphenyl~phenylmethane is unstable under the hot and humid environmental conditions and is not to be put to practical use.
Comparative Example 4:
A pressure-sensitive recording paper was prepared by the same procedures as have been described in Example 1, except for using hydrogenated terphenyl instead of l-isopropylphenyl-2-phenylethane. The colour-developing property of -the thus prepared pressure-sensitive recording paper under the very cold environ-mental conditions was examined by the procedures described in Example 3. As a result, it was found that no clearly recognizable colour-development was observed even after 30 sec of the colour developing treatment of the thus prepared pressure-sensitive recording paper, and accordingly, it was found that such a record-ing paper could not be put to practical use under the very cold environmental conditions.
Comparative Example 5:
A pressure-sensitive recording paper was prepared by the same procedures as have been described in Example 1, except for using di-isopropylnaphthalene instead of l-isopropylphenyl-2-phenylethane. The colour-development property of the thus pre-pared pressure-sensitive recording paper under the very cold ~20 environmental conditions was examlned by the procedure described in Example 3. As a result, the colour density of the 'hus pre-pared pressure-sensitive recording paper was only 12% of the standard colour density after 30 sec of the colour-developlng treatment and it was found that such a paper is not to be put to practical use under the very cold environmental conditions.
~ s~ I
Comparative Example 6:
A pressure-sensitive recording paper was prepared by the same procedures as have been descrihed in Example 1, except Eor using 1,2-ditolylethane instead of 1-isopropylphenyl-2-phenyl-ethane. The stability of the thus prepared pressure-sensitive recording paper under the hot and humid environmental conditions was examined by the procedures described in Example 2. As a result, the thus prepared pressure-sensitive recording paper showed a colour density of only 11% of the standard colour density, the fact meaning that the stability of the thus prepared pressure-sensitive recording paper is very poor.
In another experiment, the biodegradabil'ty of 1,2-ditolylethane was determined by the same procedures as have been described in Example 4. As a result, the rate of biodegradability of 1,2-ditolylethane was only 28%.
Comparative Example 7:
A pressure-sensitive recording paper was prepared by the same procedures as have been described in Example 1, except for using 1,2-dicumylethane instead of 1-isopropylphenyl-2-phenyl-ethane. The colour-developing property of the thus prepared pressure~sensitlve recording paper under the very cold environ-mental conditions was examined by the procedures described in Example 3. As a result, the colour density of the thus prepared pressure-sensltive recording paper was only 10% of the standard colour density after 30 sec of the colour-developing treatment.
In another examination, the biodegradability of ~ s~ l 1,2-dicumylethane was determined by the procedures described i.n Example 4. -~he result showed that the biodegradability of 1,2-dicumylethane was found to be only 12%.
Comparative Example 8:
A pressure-sensitive recording paper was prepared by the same procedures as have been described in Example 1, except for using l-isopropylphenyl-l-phenylethane instead of l-isopropyl-phenyl-2-phenylethane as the solvent. The stability of the thus prepared pressure-sensitive recording paper under the hot and humid environmental conditions was examined by the procedures described in Example 2. It was found that the colour density of the thus prepared pressure-sensitive recording paper was 48% of the standard colour density. In another examination on the stability of the recording paper under the hot and low-humid environmental conditions by the procedures described in Example 5, the colour density of the recordiny paper was only 50% of the standard colour density and accordingly, its stability under the above-mentioned environmental conditions was poor. In the sepa-rate examination in which the biodegradability of l-isopropyl-phenyl-l-phenylethane was determined by the procedures described in Example 4, the biodeyradability of this solvent was only 16%.
As will be understood from the above-mentioned results, the pressure-sensitive recording paper of Comparative Example 8 is poor n pr ticabillty under the severe environmental conditions.
Claims
OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A pressure-sensitive recording paper including a sheet coated with microcapsules holding internally a solution containing a colour-former and at least one solvent thereof characterized that said solution contains 1-isopropylphenyl-2-phenylethane as the solvent.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11197179A JPS5634495A (en) | 1979-08-31 | 1979-08-31 | Pressure sensitive copying paper |
| JP111971/79 | 1979-08-31 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1139561A true CA1139561A (en) | 1983-01-18 |
Family
ID=14574717
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000354708A Expired CA1139561A (en) | 1979-08-31 | 1980-06-25 | Pressure-sensitive recording paper |
Country Status (14)
| Country | Link |
|---|---|
| US (1) | US4383706A (en) |
| EP (1) | EP0029645B1 (en) |
| JP (1) | JPS5634495A (en) |
| AU (1) | AU518721B2 (en) |
| BE (1) | BE884989A (en) |
| BR (1) | BR8005428A (en) |
| CA (1) | CA1139561A (en) |
| DE (1) | DE3024020C2 (en) |
| ES (1) | ES8200271A1 (en) |
| FI (1) | FI72686C (en) |
| FR (1) | FR2464148B1 (en) |
| GB (1) | GB2058112B (en) |
| IT (1) | IT1132594B (en) |
| ZA (1) | ZA803167B (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS57116686A (en) * | 1981-01-13 | 1982-07-20 | Kureha Chem Ind Co Ltd | Pressure-sensitive recording paper |
| JPS615982A (en) * | 1984-06-21 | 1986-01-11 | Nippon Petrochem Co Ltd | Pressure-sensitive copying material |
| JPH0741738B2 (en) * | 1989-03-27 | 1995-05-10 | 日本製紙株式会社 | Coloring material |
| JP4376367B2 (en) * | 1999-09-20 | 2009-12-02 | 新日本石油株式会社 | Hydrocarbon solvent and pressure-sensitive copying material using the same |
Family Cites Families (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US386383A (en) * | 1888-07-17 | Freezing pan or tray for fish | ||
| JPS4818270B1 (en) * | 1968-03-16 | 1973-06-05 | ||
| US4003589A (en) * | 1970-07-11 | 1977-01-18 | Kureha Kagaku Kogyo Kabushiki Kaisha | Carbonless copying paper |
| JPS4921608B1 (en) * | 1970-08-24 | 1974-06-03 | ||
| JPS492126B1 (en) * | 1970-10-27 | 1974-01-18 | ||
| CA986714A (en) * | 1971-03-02 | 1976-04-06 | Yoshiaki Aida | Pressure-sensitive record material employing diaryl alkane solvents |
| BE790321A (en) * | 1971-10-20 | 1973-04-19 | Monsanto Co | SOLVENTS FOR COLORANTS OF PRESSURE SENSITIVE RECORDING MATERIALS |
| JPS5348126B2 (en) * | 1972-03-03 | 1978-12-27 | ||
| JPS492126A (en) * | 1972-04-18 | 1974-01-10 | ||
| JPS604797B2 (en) * | 1975-05-02 | 1985-02-06 | 呉羽化学工業株式会社 | Dye solvent for pressure-sensitive copying paper |
| GB1517647A (en) * | 1976-06-16 | 1978-07-12 | Monsanto Europe Sa | Solvents |
| JPS5343332A (en) * | 1976-09-29 | 1978-04-19 | Hitachi Ltd | Method of and apparatus for controlling steering angle of optically guided unmanned vehicle |
| JPS5489817A (en) * | 1977-12-27 | 1979-07-17 | Fuji Photo Film Co Ltd | Recording material |
-
1979
- 1979-08-31 JP JP11197179A patent/JPS5634495A/en active Granted
-
1980
- 1980-05-27 ZA ZA00803167A patent/ZA803167B/en unknown
- 1980-06-10 AU AU59180/80A patent/AU518721B2/en not_active Ceased
- 1980-06-25 CA CA000354708A patent/CA1139561A/en not_active Expired
- 1980-06-26 DE DE3024020A patent/DE3024020C2/en not_active Expired
- 1980-08-07 FI FI802491A patent/FI72686C/en not_active IP Right Cessation
- 1980-08-27 BR BR8005428A patent/BR8005428A/en unknown
- 1980-08-29 ES ES495041A patent/ES8200271A1/en not_active Expired
- 1980-08-29 FR FR8018834A patent/FR2464148B1/en not_active Expired
- 1980-08-29 EP EP80303003A patent/EP0029645B1/en not_active Expired
- 1980-08-29 IT IT8024379A patent/IT1132594B/en active
- 1980-08-29 BE BE0/201916A patent/BE884989A/en not_active IP Right Cessation
- 1980-08-29 GB GB8028074A patent/GB2058112B/en not_active Expired
-
1981
- 1981-12-08 US US06/328,737 patent/US4383706A/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| EP0029645B1 (en) | 1983-07-20 |
| BR8005428A (en) | 1981-03-10 |
| EP0029645A2 (en) | 1981-06-03 |
| EP0029645A3 (en) | 1981-08-05 |
| FI72686C (en) | 1987-07-10 |
| AU5918080A (en) | 1981-03-05 |
| GB2058112B (en) | 1983-09-21 |
| ZA803167B (en) | 1981-05-27 |
| AU518721B2 (en) | 1981-10-15 |
| DE3024020C2 (en) | 1982-09-23 |
| IT1132594B (en) | 1986-07-02 |
| DE3024020A1 (en) | 1981-03-26 |
| BE884989A (en) | 1981-03-02 |
| ES495041A0 (en) | 1981-11-01 |
| JPS5634495A (en) | 1981-04-06 |
| GB2058112A (en) | 1981-04-08 |
| FI72686B (en) | 1987-03-31 |
| FR2464148A1 (en) | 1981-03-06 |
| FI802491A (en) | 1981-03-01 |
| FR2464148B1 (en) | 1986-03-07 |
| US4383706A (en) | 1983-05-17 |
| IT8024379A0 (en) | 1980-08-29 |
| JPS6150797B2 (en) | 1986-11-06 |
| ES8200271A1 (en) | 1981-11-01 |
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