JPH02196685A - Pressure-sensitive recording sheet - Google Patents

Abstract

PURPOSE:To obtain a pressure-sensitive recording sheet having a high color forming speed and imparting a high developed color density by incorporating a metal salt of aromatic carboxylic acid and a specific bisaryl oxyalkane derivative in an electron acceptive coupler layer. CONSTITUTION:In a pressure-sensitive recording sheet obtaining a developed color image by the reaction of an almost colorless electron donating dye (color former) and an electron acceptive coupler (coupler), the electron acceptive couples layer contains a metal salt of aromatic carboxylic acid and a bisaryl oxyalkane derivative represented by general formula (I) wherein R is a 2-10C branched alkylene group, an aralkylene group or an alkylene group having one or more group selected from an oxygen atom, a sulfur atom, a halogen atom, a carbonyl group and an oxycarbonyl group, X, Y, Z, X' and Z' may be same or different and are a hydrogen atom, a lower alkyl group, a lower alkoxy group, a halogen atom, an aralkyl group, an alkoxycarbonyl group or an alkylthio group and X and Y and X' and Y' may be bonded to each other to form a ring. A and B are an oxygen atom or a sulfur atom.)

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a pressure-sensitive recording sheet. More specifically, the present invention relates to a pressure-sensitive recording sheet that obtains a colored image by a reaction between a nearly colorless electron-donating dye (hereinafter referred to as a color former) and an electron-accepting color developer (hereinafter referred to as a color agent).

(Prior art) A pressure-sensitive recording sheet consists of a top sheet made of a support coated with a microcapsule layer containing microcapsules obtained by dissolving a coloring agent in a suitable solvent and converting its oil droplets into carboxylates, and a color developer. A combination of a lower paper coated with a color developer layer containing on another support, and in some cases a middle paper coated with a microcapsule layer on one side of the support and a color developer layer on the other side. or one in which the capsule and the color developer are contained on the same side of the support, or one in which one of the capsule or the color developer is contained in the support and the other is coated. There is.

Well-known color developers for pressure-sensitive recording sheets include clay materials such as acid clay, activated clay, acpulgite, zeolite, bentonite, and kaolin, metal salts of aromatic carboxylates, and phenol formaldehyde resins.

Performance that a pressure-sensitive recording sheet should have.

1) High color density.

2) There is little decline in color developing ability due to aging.

3) Fast color development speed.

4) The color image should have excellent light resistance.

5) Less yellowing on the developing surface.

etc. can be mentioned.

Among currently known color developers, metal salts of aromatic carbonaceous compounds exhibit the best overall performance.

However, among the above-mentioned performances, the speed of color development is not sufficient, and there is a drawback that the color density immediately after printing is low, especially under low temperature conditions, and it takes a long time to reach the saturated density. Also, the density of one color is not sufficient.

(Objective of the Invention) An object of the present invention is to provide a pressure-sensitive recording sheet that has a fast coloring speed and a high coloring density.

(Structure of the Invention) An object of the present invention is to provide a pressure-sensitive recording sheet that produces a colored image by a reaction between a nearly colorless electron-donating dye and an electron-accepting color developer, in which the electron-accepting color developer layer is ( a) a metal salt of an aromatic carbonaceous compound and (b)
) This was achieved by a pressure-sensitive recording sheet characterized by containing a bisaryloxyalkane derivative represented by the following general formula (1).

Y′ (in the above formula, R is a branched alkylene group having carbons W12 to W10,
The aralkylene group is an alkylene group having one or more groups selected from oxygen atom, sulfur atom, halogen atom, carbonyl group, oxycarbonyl group, X, Y, Z, X'
, Y' and z' and t' may also be hydrogen atoms, lower alkyl groups.

Represents a lower alkoxy group, a halogen atom, an aralkyl group, an alkoxycarbonyl group, or an alkylthio group, X and Y, X' and Y' may be bonded to each other to form a ring, A and B are an oxygen atom or a sulfur atom ) The metal salt of the aromatic carbonaceous compound used in the present invention is disclosed in, for example, U.S. Pat.
No., Special Publication No. 51-25174, Japanese Patent Publication No. 62-1948
No. 6, JP-A No. 63-254124, etc.

The aromatic carboxylic acid in the above-mentioned metal salt of aromatic carboxylic acid is usefully one having a hydroxyl group at the ortho or bara position with respect to the carboxy group, and among these, salicylic acid derivatives are preferred, and substitution with an alkyl group, aryl group, aralkyl group, etc. It is preferable that the substituent group has a total number of carbon atoms of 8 or more.

Specific examples of preferred metal salts of salicylic acid derivatives used in the present invention include 3,5-di-t-butylsalicylic acid,
3,5-di-t-octylsalicylic acid, 3,5-di-t
-nonylsalicylic acid, 3゜5-di-t-dodecylsalicylic acid, 3-methyl-5-t-dodecylsalicylic acid, 3-
t-dodecylsalicylic acid, 5-t-dodecylsalicylic acid, 5-cyclohexylcyclohexylsalicylic acid, 3゜5-bis(α-methylbenzyl)salicylic acid, 3゜5-
Bis(α,α-dimethylbenzyl)salicylic acid, 3-methyl-5-(α-methylbenzyl)salicylic acid, 3-(
α,α-dimethylpencil)-5-methylsalicyl! ,
3-(α,α-dimethylbenzyl)-6-methylsalicylic acid, 3-(α-methylbenzyl)-5-(α,α-dimethylbenzyl)salicylic acid, 3-(α,α-dimethylbenzyl)-6- Nitylsalicylic acid, 3-phenyl-5
- Zinc salts, nickel salts, aluminum salts of salicylic acid resin, which is a reaction product of (α,α-dimethylbenzyl)salicylic acid, carboxy-modified terpene phenol resin, and 3,5-bis(α-methylbenzyl)salicylic acid and benzyl chloride. , calcium salts, and the like.

Next, specific examples of the bisaryloxyalkane derivatives according to the present invention will be shown, but the present invention is not limited thereto.

1) 1,2-diphenoxypropane 2) 1-phenoxy-2-P-tolyloxyprono(n) 3) 1-7enoxy 2-m-)lyloxypropane 4) 1-phenoxy-2-o-tolyloxy Prono(5)1-phenoxy-2-p-chlorophenoxyprono1ne6) 1-naphthyl(2)oxy-2-7enoxypropane7) 1-phenoxy-2-1)-methoxyphenoxypropane8 ) 1.5-diphenoxy-3-oxapentane 9>1.5-di-p-tolyloxy-3-oxapentane 10) 1.5-bis-p-methoxyphenoxy-3-oxapentane 11) 1.5- Bis-p-ethoxyphenoxy-3-oxapentane 12) 1,5-diphenoxy-3-thiapentane 13)
1,7-Diphenoxy-3,5-dioxaheptane 14) 1,7-dinaphthyl (2) Oxy-3,5-dioxaheptane 15) β-phenoxyethyl phenoxy acetate 16) 1,3-bis(o- tolyloxymethyl)benzene 17) 1-phenoxy-2-phenylthioethane 18)
1-phenoxy-2-P-methoxycarbonylphenoxypropane 19) 1-7 enoxy 2-P-methylthiophenoxypropane and the like.

The amount of the bisaryloxyalkane derivative used is 1 to 400 parts by weight, preferably 5 to 200 parts by weight, based on 100 parts by weight of the aromatic carbonaceous metal salt.

The metal salt of the aromatic carbonaceous compound and the bisaryloxyalkane derivative are mechanically dispersed in an aqueous system using a ball mill, an attritor, a sand mill, etc., and then used. The aromatic carbonaceous metal salt and the saryloxyalkane derivative may be dispersed separately, or both may be dispersed together.

When preparing the coating solution, use of inorganic pigments such as titanium oxide, zinc oxide, silicon oxide, calcium carbonate, aluminum hydroxide, kaolin, activated clay, talc, barium sulfate, magnesium oxide, etc. can improve coating suitability and hiding power, and improve visibility. Favorable effects such as improved color performance can be obtained. The preferred amount of the inorganic pigment used is 1 to 1 part by weight of the color developer.
00 parts by weight, and more preferably 2 to 40 parts by weight.

Binders for the coating solution include latexes such as styrene-butadiene copolymer latex, vinyl acetate latex, and acrylic ester latex, polyvinyl alcohol, polyacrylic acid, maleic anhydride-styrene copolymer, starch, casein, Synthetic or natural polymeric substances such as gum arabic, gelatin, carboxymethylcellulose, methylcellulose, etc. are used.

The final amount of developer applied to the support was 0°1 g/
m place~3. Og/m” preferably 0.2 g/m snow ~1
．． Og/m" is appropriate.

The color former that reacts with the primary color agent used in the recording sheet of the present invention is not particularly limited, but includes triphenylmethane phthalide compounds, fluoran compounds, phenothiazine compounds, indolylphthalide compounds, and indolyl azaphthalide. type compounds, leucoauramine type compounds, rhodamine lactam type compounds, triphenylmethane type compounds,
Examples include triazene compounds and spiropyran compounds.

The color former is dissolved in a solvent, encapsulated, and applied to a support.

As a solvent, natural or synthetic oils can be used alone or in combination. Examples of solvents are kerosene, paraffins, naphthenic oils, alkylated biphenyls.

Examples include alkylated terphenyls, chlorinated paraffins, alkylated naphthalenes, diarylalkane, and phthalate esters.

As a method for producing color former-containing microcapsules, an interfacial polymerization method, an internal polymerization method, a phase separation method, an external polymerization method, a core cell basis method, etc. are used.

In preparing a coating solution containing microcapsules containing a color former, a water-soluble binder or a latex binder is generally used. Further, capsule additives such as cellulose powder, starch particles, talc, etc. are added to obtain a coloring agent-containing microcapsule coating solution.

The performance of the color developer sheet for pressure-sensitive recording paper of the present invention was tested using the following color former-containing microcapsule sheet.

[Preparation of microcapsule sheet containing color former] 5.0 g of crystal violet lactone, 1°0 g of benzoyl leucomethylene blue and 3-[4-(
dimethylamino)-2-ethoxyphenyl]-3-(2
-2.0 g of methyl-1-ethyl-3-indolyl)-14-azaphthalide and 100 g of diisopropylnaphthalene.
dissolve in To this oily liquid, 15 g of tolylene diisocyanate 37/1 mole adduct of trimethylolpropane was added as a polyvalent isocyanate, and a butylene oxide adduct of ethylenediamine was added as an alkylene oxide adduct of amine (the number of moles of butylene oxide added to ethylenediamine was 16.8 Mol, molecular weight 1267) 3.0g
was dissolved and the primary solution was adjusted to Fl.

Next, 10 g of polyvinyl alcohol and 5 g of carboxymethyl cellulose were dissolved in 140 g of water to prepare a secondary solution. While vigorously stirring the secondary solution, the primary solution was poured to form an oil-in-water emulsilane. When the size of the oil drop left reached 6°0μ, stirring was weakened, and then 100g of water at 20°C was added to the emulsion, and the temperature of the system was gradually raised to 65°C. I kept it.

To the capsule liquid thus obtained, 80 g of a 15% aqueous solution of polyvinyl alcohol, 20 g of solid content of carboxy-modified SBR latex, and starch particles (average particle size 15 μm) were added.
)60g was added.

Next, water was added to adjust the solid content concentration to 20% to prepare a coating solution.

The dry weight of this coating liquid was 4.0 g/rd.
The mixture was coated onto 40 glrd base paper using an air knife coater and dried to obtain a microcapsule sheet.

The color developer sheet for pressure-sensitive recording paper of the present invention will be specifically explained below with reference to Examples, but the invention is not limited to these Examples.

(Embodiments of the invention) Example 1-1~! -8 and comparative example! [Preparation of dispersion] 3.5-bis(α-methylbenzyl)zinc salicylate 1
5 parts, 15 parts of the bisaryloxyalkane derivative shown in Table 1, 120 parts of calcium carbonate, 10 parts of activated clay, 20 parts of zinc oxide, 1 part of sodium hexametaphosphate and 2 parts of water.
A dispersion (A) was obtained which was atomized using a sand mill.

[Adjustment of coating liquid]

100 parts of a 10% PVA-117 (manufactured by Kuraray) aqueous solution and 7 parts (as solid content) of carboxy-modified SBR latex (manufactured by Sumitomo Naugatac, 5N307) were added to 300 parts of dispersion liquid (A), so that the solid content concentration was 20%. Water was added to obtain a coating solution.

(Application of color developer sheet) This coating liquid was applied to base paper of 0g/m'' with an air knife coater so that the solid content was 5.0g/m'', and dried to obtain a color developer sheet. Ta.

Examples ■-1 to ■-4 and Comparative Example ■ [Preparation of dispersion liquid] 15 parts of zinc 3.5-di-t-octylsalicylate, 1st
Using 7 parts of the bisaryloxyalkane derivative shown in the table, 120 parts of calcium carbonate, 30 parts of kaolin, 20 parts of zinc oxide, 1 part of sodium hexametaphosphate, and 200 parts of water, a dispersion (B) was obtained by atomization using a sand mill. Na.

[Adjustment of coating liquid]

100 parts of a 10% PVA-117 (manufactured by Kuraray) aqueous solution and 5 parts (as solid content) of Carbogyshi-modified SBR latex (manufactured by Sumitomo Naugatac, 5N-307) were added to 300 parts of dispersion liquid (B), and the solid content concentration was adjusted. Add water to 20%! A coating liquid was obtained.

[Application of color developer sheet]

This coating liquid was applied to 50 g/nr base paper using an air knife coater so that the solid content was 5.0 g/g.
It was dried to obtain a color developer sheet.

Evaluation tests were carried out as pressure-sensitive recording sheets by combining each of the above color developer sheets and color former-containing microcapsule sheets, and the results are shown in Table 1. The evaluation test was conducted using the following method.

(1) Color development speed and color density test Color developer sheet and color developer-containing microcapsule sheet
The microcapsule layer of the color former-containing microcapsule sheet was overlaid on the color developer sheet in the constant temperature constant room at 35% of R8.
Color was developed by applying a load pressure of 00 kg/c- for 1 second. The density (Dl) was measured 15 seconds after pressurization using a Macbeth reflection densitometer.

Thereafter, this non-color developer sheet was left at room temperature (25°C) for 24 hours, and then measured with a Macbeth reflection densitometer to determine the density (D2).
) was measured.

The Dt/D'a ratio was defined as the color development rate, and Dl2 was defined as the color development density.

As shown in Table 1, the primary color agent sheet of the present invention has excellent color development speed and color source, and has extremely good performance compared to the comparative color developer sheet.

Claims (1)

[Scope of Claims] A pressure-sensitive recording sheet that obtains a colored image by a reaction between a nearly colorless electron-donating dye and an electron-accepting color developer, the electron-accepting color developer layer comprising (a) an aromatic carbonaceous dye; Metal salt and (b
) A pressure-sensitive recording sheet comprising a bisaryloxyalkane derivative represented by the following general formula (I). ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (I) (In the above formula, R is selected from a branched alkylene group having 2 to 10 carbon atoms, an aralkylene group, or an oxygen atom, a sulfur atom, a halogen atom, a carbonyl group, and an oxycarbonyl group. X, Y, Z, X', Y
' and Z' may be the same or different and represent a hydrogen atom, a lower alkyl group, a lower alkoxy group, a halogen atom, an aralkyl group, an alkoxycarbonyl group, or an alkylthio group, and X and Y, X' and Y' are bonded to each other. A and B may represent an oxygen atom or a sulfur atom. )