JPS61284479A - Backing paint having large solid matter content and coating sheet for pressure sensitive recording member - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to backing (CB) components of pressure sensitive recording members, generally referred to as carbonless copy paper. The present invention relates to high solids content sodium carboxymethyl cellulose (CMC) based formulations having a high coating viscosity and to papers coated with such formulations.

BACKGROUND OF THE INVENTION Non-carbon paper has two or more superimposed sheets. These sheets have on their back side a paint containing a color-forming substance, often called a backing or CB. This paint consists of a continuous matrix or microcapsules containing a color-forming substance, which are superimposed in use. The receiver placed in contact with the back side of the sheet is coated with a composition containing a coloring agent component that reacts with the color-forming substance on the top surface of the sheet. When partial pressure is applied to the top sheet, the color-forming substance is released. The color-forming substance is released by the destruction of the coating film, and the receiver reacts by contacting the sheet with the co-reactant or color developer paint.The area corresponds to the place where the color-forming substance is released when pressure is applied. A visible colored image is produced on the top sheet, such that the pressure applied to the top sheet produces a corresponding mark on the top surface of each of the other sheets of the plurality.

The prior art discloses the production of paints containing color-forming substances (also referred to as color-forming precursors or leuco dyes) dispersed in a solvent. For example, U.S. Patent No. 431374
No. 83 and No. 40826i88 and British Patent No. 1
Prior patents such as No. 2807H disclose CB coatings for pressure-sensitive recording materials consisting of an oily solvent and a carboxymethylcellulose precipitate containing a color-forming substance. It is emulsified and metal salts are added to precipitate the cellulose as a separate phase with the droplets of oily dye solution contained therein. The obtained emulsion is applied to the back side of the uppermost sheet of the non-carbon copy system and dried. Crosslinked resins are often added to this emulsion to strengthen the resulting coating.

PROBLEMS TO BE SOLVED BY THE INVENTION Although these paints have been commercially successful, the high solids content of CBAI based on previous embodiments of this technology
IF:#:, the product has poor stability and its viscosity is unadjustable and too high for the coating equipment and methods currently in use. CB paint with small solid content (
For example, non-aqueous components (20%) require high energy consumption and long drying times. It is therefore desirable to provide a high solids content CB paint with efficient coating viscosity.

It is not possible to increase the solids content of known CMC-based coating compositions by mere water reduction because this would result in significant viscosity problems. CMC aqueous solutions have the characteristic that their viscosity increases exponentially as the CMC concentration increases. Thus, any benefit gained from simply increasing the CMC content in producing a coating composition that dries more quickly is offset by the viscosity of such compositions becoming too high, impairing workability.

It is an object of the present invention to provide improved CB coatings with low viscosity and high solids content for better application to paper and other substrates. Another objective is to increase drying efficiency by providing coating compositions with higher solids content and lower water content. Yet another objective is to increase labor and energy savings by producing coating compositions with low moisture content. Another object is to provide a CB paper with improved chromophore release efficiency to obtain improved images for computers and dot matrix printers using pressure sensitive paper. Still another objective is to create a CB paint that has a white appearance. Yet another objective is to reduce distortion of the paper substrate due to rough wetting. Yet another object is to provide a CB paint that can be applied to paper making machines.

[Means for solving problems]

High solids content CB coatings and improved CB products with efficient and stable coating viscosities can be applied to specific types of CMCs such as acrylic resins, organic crosslinkers and CMs.
By using the formulation of the present invention, a high solids content, i.e., about 30% by weight of non-aqueous materials, was found to be produced by use with metal salts capable of causing precipitation of C. The above amounts result in a CB coating composition having an efficient coating viscosity that can reduce many of the problems found in conventional CB coating compositions.

This paintable formulation has a CMC1 preferably a degree of substitution of 0.
．． An emulsion of an oil containing one or more color-forming reactants in an aqueous solution of sodium CMC ranging from 65 to 1.8, a wall-forming acrylic resin, a salt of a polyvalent metal, an organic cross-linking agent and any other coexisting options. components, which provide a total solids content of at least 30% by weight, preferably at least 35% by weight, in the formulation, and which meet the needs of the particular coating equipment used and coating at the selected web speed. It is included in an amount sufficient to provide a Pulckfield viscosity in the range of about 50 to about 5000 centipoise (cps), which is set accordingly. As used herein, weight percentage solids includes all components other than ice in the formulation, i.e., in a preferred embodiment, including oil and dissolved dye or dyes in the paint. The wall-forming acrylic resin is a carboxylated polyethyl acrylate/carboxylated polyethyl acrylate with a most preferred ratio of ethyl acrylate to methacrylate of about 2:1.
It is a copolymer of methyl methacrylate. Preferably, the organic crosslinking agent is polyamide-epichlorohydrin or other resin capable of crosslinking both CMC and carboxylated acrylic resins.

In presently preferred embodiments, the CMC used has a low viscosity (60-170 cps as a 6% aqueous solution) and a high degree of substitution, such as from 1.1 to 1.5.

In another aspect, the present invention includes an improved CB receipt comprising a web having an adhesive and dried paint of the type described above that releases color formers upon application of pressure. The CB receipt image density is improved, the threshold pressure is low, and the cost is low.

DESCRIPTION OF THE PREFERRED EMBODIMENTS According to the present invention, low viscosity CMC with a degree of substitution between about 0.85 and 1.8 is dissolved in water. , CMC is an anionic, water-soluble polymer derived from cellulose. The degree of substitution is the average number of carboxymethyl groups that are substituted per anhydroglucose unit. A high degree of substitution improves the compatibility of CMC with other water-soluble compounds.6 The CMC used in the present invention has a degree of substitution of 1. l
~1.5. namely, alkali metal CMCs such as sodium CMC groups with an average of 1.1 to 1.5 carboxymethyl groups per anhydroglucose unit.

A wall-forming acrylic resin is added to this aqueous solution. B-Ken F. Gutdrich (B) as a preferred resin
, F. Goodrich) (Carposet) (C
arbst4t) 514H is a carbosylated copolymer of polyethyl acrylate/methyl methacrylate, preferably in a ratio of about 2:1. Other resins, such as Rohm & Hass Color 7
ACRYSOL-WS-24 To L Te obtained-1? e Carboxylated copolymers of rubobutyl acrylate and styrene can also be used.

A solution of the dye in an oil solvent is then added to this acrylic resin-CM.
Add to C solution. Suitable dyes and oil solvents are well known in the art. A preferred oil-dye solution consists of a basic color-forming lactone or phthalide dye that is colorless or light-colored and develops color on contact with acidic substances, dissolved in an effective solvent such as flukylbiphenyl. The particular dye(s) and oil(s) used do not themselves form part of the invention. However, in a preferred embodiment, the dye or dyes used are in an active oil containing 3 to 12 dyes.
Dissolved in a concentration of % by weight.

A crosslinking agent, such as a cationic water-soluble polyamide-epichlorohydrin resin that crosslinks the carboxymethyl cellulose and the water-soluble wall-forming carboxylated acrylic resin, is added to the resulting two-phase mixture. Other useful crosslinking agents include formaldehyde resins or formaldehyde-providing resins such as melamine formaldehyde resins. Hercule
Kymene 557 obtained from Les Co., Ltd.
H is a preferred crosslinking agent. Kimene 557H is a highly efficient cationic, high wet strength resin that functions in acidic or alkaline conditions. The combination of CMC, acrylic resin, and such crosslinking materials produces a highly flexible and strong water-insoluble film. According to research reported by Hercule, chimene reacts with hydroxyl and carboxyl groups, and primarily with carboxyl groups.

An aluminum nitrate solution (eg, 5% by weight or less) is then added to the emulsion. Aluminum nitrate is used in this CB formulation to insolubilize the HaCMC. Finally, a starch dispersion or other particle dispersion, which acts as a spacer material, is added to this mixture.

The resulting coating formulation has a high solids content of at least 30%. The viscosity can vary widely and can be easily adjusted for specific applications by reducing water and/or using higher viscosity CMC. For air knife coatings, the viscosity of the composition measured using a Pruckfield RVF viscometer (44 spindle) at 11000 rpm is between 50 and 25.
0, preferably 60 to 100 cps. For roll coatings, the viscosity should normally range from 50 to 12 Qcps.

For rod painting, it is between 50 and 60θcps,
And for blade painting 300-5000cps
It is between. The particular viscosity used will necessarily vary depending on the coating equipment and coating speed used.

In a preferred embodiment, CM of the internal phase of oil and dye
The ratio of C and organic crosslinker to external phase is increased compared to the prior art. For example, in the preferred CB paper of the present invention, the amount of internal phase is about 3% compared to prior art coating compositions.
Increased by 5%. The formulation is typically applied to the back side of paper or other substrates in non-carbon copy paper applications.
Approximately 3. Coated and dried at a coating weight of OOg (dry weight) or more. When pressure is applied to the base material, 1
A color-forming substance is transferred by the oil to an underlying sheet containing a substance that reacts with the dye, producing a colored image corresponding to where pressure is applied.

The essential components of the coating composition of the present invention include CMC with a degree of substitution between 0.85 and 1.8, a wall-forming carboxylated acrylic resin, an organic crosslinker and a metal salt; generally the composition contains 6100 parts of the CMC used. (Dry weight) Nitsuite, approx. 50
It should contain between ~200 parts of acrylic resin, between 10 and 150 parts of crosslinker, between 300 and 1000 parts of oil and dye and between 4.4 and 12.2 parts of salt. For every 4100 parts of OMC used, the wall-forming resin can be present at about 60-100 parts, the crosslinker at 60-100 parts, the oil and dye at 800-800 parts and the metal salt at 5-6 parts. Preferably, when spacer particles are preferably used, 100 to 0 per 00 parts of CMCI
Parts O are present, preferably in the range 200-300 parts.

The practice of the present invention provides significant advantages over conventional formulations. CB with higher solids content and lower viscosity
Cocoings can be applied and dried at greater machine speeds and with significant energy savings. Paint preparation and productivity are increased by the ability to obtain fewer patches while maintaining the same dry coat weight.

This coating has greater whiteness than conventional CMC-based CB compositions and can also be imaged with lower pressures due to improved release efficiency.8 In the composition of the present invention, CMC, carboxylated The acrylic resin and crosslinker work together to enable the preparation of aqueous coating compositions with controllable and stable viscosity properties at any one point within a wide viscosity range.

The invention will be further understood by the following examples, which are given by way of illustration only and are non-limiting.

Example 1 A CB coating composition for blue marks with a high solids content was prepared by the following method. All ratios are by weight. The following solutions were prepared.

H,0920,00 Carboxymethyl cellulose 80.0 (1
, 20S, low viscosity) / Solidity of the obtained solution 8% 4 Examination 1" Oil and dyes / 1820.0 Dye content of the obtained solution 4.7% Week 31 Tensile Starch spacer dispersion / 1000.0 Solidity of the obtained solution 32.48% 1/Ha-CMCl2UL obtained from Hercule
820 parts of deodorized kerosene, preferably obtained from Penreco, and 100 parts of furkylbiphenyl (Suresol 290, obtained from Koch Che+5ical) and crystalnoveiolet lactone and Cobichem
m) Cave [Hilton Davis
).

l/preferably water; CM obtained from Hercule
C-7H; and starch particles (approximately 10-25 microns in size).

To 1300 parts of Formulation A are added t2os of carboxylated polyethyl acrylate/methyl methacrylate copolymer (preferably Calpocet 514H).

To the resulting mixture, 600 parts of Formulation B are added with stirring. Continue stirring until the emulsification is complete. Next, add 100 parts of a polyamide-epichlorohydrin crosslinking agent (preferably Kymene 557) to the emulsion.
Add H) 6 Next, 170 parts of an aqueous aluminum nitrate solution containing 1.41 parts of solids was gradually added to 1200.0 parts of the emulsion. At this point, the solids content of the paint was 31%. Pulckfield viscosity at 100 rpts [temperature approximately 25.8°C (78°F), pH 5.93]
becomes 250 cps. The oil droplet size is 2 to IO microns. Finally, 300 parts of Formulation C are added to give a coating composition with a solids content of 32% and a Pulckfield viscosity of 200 cps.

Example 2 A CB paint with a high solids content was prepared by the following method.

Formulations A-C are prepared according to Example 1.

To 670 parts of Formulation A, 120 parts of polyethyl acrylate/methyl methacrylate copolymer are added. To the resulting mixture add 60 parts of Formulation B with stirring. Then add 480 parts of bolanamide epichlorohydrin crosslinker. Next add 1.4% solids to 1200 parts of emulsifier. Gradually add 180 parts of aluminum nitrate containing. At this point the temperature of the paint formulation is 78
°F, pH is 5.8, solids content is 35
%. The Pulckfield viscosity is 100 cps and the oil droplet size is 2 to 10 microns.

Finally, 340 parts of Formulation C are added to the coating composition, resulting in a solids content of 35.4% and a Pulckfield viscosity of 90 cps. After stirring for 5-10 minutes, the viscosity is 120 cps.

Example 3 To 785 parts of Formulation A, 125 parts of carboxylated polyethyl acrylate/methyl methacrylate copolymer are added. Add 800 parts of Formulation B to the resulting mixture with stirring. Then add 400 parts of polyamide shrimp glolhydrin crosslinker. Then add 180 parts of aluminum nitrate solution to 1200 parts of this emulsion. (1.4% solids) is gradually added. At this point, the solids content of the paint was 42%, the viscosity was 1I30cps,
The pH is 5.8 and the temperature is 78'F. The particle size of the oil droplets is 2-10 microns. Finally, 220 parts of Formulation C are added to the coating composition, resulting in a solids content of 41%.
The viscosity is 130 cps.

4.8 to 5.2 g of the coating composition described in each of the above Examples was applied to a white paper substrate using a laboratory air knife coater.
/m” and tested against similar applications in the same range of coating weights of coating compositions representative of the prior art. A comparison of the results with those obtained by the prior art is as follows.

1. Chromogen release efficiency: A sheet strip containing the test paint was placed in such a way that the test paint was superimposed on the color developer coating of the sheet strip. It was run between steel calender rolls under pressure of .

Using a densitometer, a reflectometer, the Uke read the non-imaged areas of the sheet, and after 80 seconds of calendering, the Uke read the imaged areas of the sheet as well.

The image density for each case was then calculated as follows: (The lower the "Image Density" value, the darker or denser the image) The results are as follows: 111 Cliffs Coatings Showing Prior Art 50 .0"Example 3
” coating 45.6n=4 2 Paint fading The reflectance readings of the uncoated paper substrate and the test paint were measured using Minolta Chroma meters.
Measured using (2). In each case a six-sheet M carrier was placed below the measuring chip, with the sheets of each stack facing the measuring chip with the relevant side of the sheet. The results obtained are as follows.

↓ A Top uncoated paper +94.000 -0.85 +
4.45 Showing prior art +93.200 -1.
65 + 9.9 Painted object "Example 3 J + 93.325-1.15
+ 8.325 coatings The obtained values raJ and "b" are shown in the accompanying drawings. The coated product of "Example 3" is shown.

The accompanying drawings are graphs showing reflectance readings for uncoated paper substrates, paper substrates coated with low solids coating compositions according to the prior art, and coating compositions formulated according to the present invention. . The graph shows the improved whiteness of CB paper made according to the present invention.

These data show that the coated article of "Example 3" is much closer in color to the white paper substrate than the coated article representing the prior art (
preferred).

The invention may be embodied in other specific forms without departing from its spirit or scope. Accordingly, other embodiments are also within the scope of the claims.

[Brief explanation of drawings]

The figure is a graph showing the improved whiteness of CB paper according to the present invention in comparison with coated paper according to the prior art.

Claims (20)

[Claims] (1) A paintable aqueous formulation with a high solids content for application to a substrate to produce a pressure-releaseable colorant, wherein said formulation comprises: carboxymethylcellose, a polyvalent metal; a salt, a wall-forming carboxylated acrylic resin, an organic crosslinker, spacer particles, and a color-forming dye dissolved in an oily solvent, the material having a total non-aqueous content of at least 30% by weight and about 25.6% by weight; The above formulation is present in an amount sufficient to have a Brookfield viscosity at 78° F. of about 50 to about 5000 cps. (2) Substitution degree of carboxymethyl cellulose is 0.65
~1.8 and the viscosity as a 6% aqueous solution is 17
2. A formulation according to claim 1, which has a molecular weight of less than 0 centipoise. (3) A formulation according to claim 1, wherein the organic crosslinking agent is polyamide-epichlorohydrin. (4) A formulation according to claim 1, wherein the wall-forming acrylic resin is a carboxylated copolymer of polyethyl acrylate/methyl methacrylate. (5) The formulation according to claim 1, wherein the viscosity is within the range of 50 to 250 cps. (6) the material has a total nonaqueous content of at least 35% by weight and has a Brookfield viscosity of 60 to 100%;
A formulation as claimed in claim 1 for air knife coatings present in a sufficient amount to provide within the range of cps. (7) The percentage of dye in oil in the formulation is 3% to 1
A formulation according to claim 1 within the range of 2%. (8) The degree of substitution of carboxymethyl cellulose is 1.1 or more
1.5 and its viscosity as a 6% aqueous solution is less than or equal to 170 cps. (9) The following materials in the following parts by weight: ￥Material￥　￥Part by weight￥ Metal salt 4.4-12.2 CMC 100 Acrylic resin 50-200 Crosslinking agent 10-150 Dyes and oils 300-1000 Spacer particles 100-500 A formulation according to claim 1 comprising: (10) The following materials in the following parts by weight: ￥Material￥　￥Part by weight￥ Metal salt 5-8 CMC 100 Acrylic resin 60-100 Crosslinking agent 60-100 Dyes and oils 600-800 Spacer particles 200-300 A formulation according to claim 1 comprising: (11) A paintable aqueous formulation with a high solids content for application to a substrate to produce a pressure-releaseable colorant, comprising: carboxymethylcellose, a salt of a polyvalent metal, a wall; a body-forming carboxylated acrylic resin, an organic crosslinker, spacer particles, and a color-forming dye dissolved in an oily solvent, the material having a total nonaqueous content of at least 30% by weight and about 25.6°C (78°C); The formulation is present in an amount sufficient to provide a Brookfield viscosity of about 50 to about 5000 cps at 3.0 cps per square meter.
A coated sheet for a pressure-sensitive recording member, which releases a color-forming substance when pressurized, and includes a base material provided on the surface by adhering and drying with a coating weight of 0 g or more. (12) The degree of substitution of the carboxymethylcellulose is 0
．． 65 to 1.8 and has a viscosity of 170 centipoise or less as a 6% by weight aqueous solution. (13) The coated sheet for a pressure-sensitive recording member according to claim 11, wherein the organic crosslinking agent is polyamide-epichlorohydrin. (14) The coated sheet for a pressure-sensitive recording member according to claim 11, wherein the wall-forming acrylic resin is a carboxylated copolymer of polyethyl acrylate/methyl methacrylate. (15) The coated sheet for a pressure-sensitive recording member according to claim 11, wherein the viscosity is within a range of 50 to 250 cps. (16) the material has a total nonaqueous content of at least 35% by weight and a Brookfield viscosity of 60 to 10%;
A coating sheet for a pressure-sensitive recording member according to claim 11, which is used for air knife coating and is present in an amount sufficient to bring the pressure within the range of 0 cps. (17) The percentage of dye in oil in the formulation is 3% or more
A coated sheet for a pressure-sensitive recording member according to claim 11, wherein the coating sheet is within a range of 12%. (18) The degree of substitution of carboxymethylcellulose is 1.1
1.5 and has a viscosity of 170 cps or less as a 6% aqueous solution. (19) Add the following materials to the following parts by weight: ¥Materials¥¥Parts by weight¥Metal salt 4.4-12.2 CMC 100 Acrylic resin 50-200 Crosslinking agent 10-150 Dye and oil 300-1000 Spacer particles 100- 500. A coated sheet for a pressure-sensitive recording member according to claim 11. (20) The above containing the following materials in the following parts by weight: ¥Material¥¥Parts by weight¥Metal salt 5-6 CMC 100 Acrylic resin 60-100 Crosslinking agent 60-100 Dye and oil 600-800 Spacer particles 200-300 A coated sheet for a pressure-sensitive recording member according to claim 11.