Reversible thermochromic aqueous ink composition and writing instrument using same

A technology for writing instruments and compositions, applied in writing instruments, household appliances, inks, etc., can solve the problems of easy pigment sedimentation, reduced ink discharge, low viscosity, etc., and achieve the effect of excellent dispersion stability

Active Publication Date: 2020-06-09

PILOT PEN CO LTD +1

28 Cites 2 Cited by

AI-Extracted Technical Summary

Problems solved by technology

However, such an ink composition tends to lower its viscosity when vibration is applied from the outside, so when a pigment with a large specific gravity is used, the pigment tends to settle, and the viscosity cannot be lower...

Method used

According to the specific gravity of the microcapsule pigment adjusted above, the particle diameter of the microcapsule, the composition contained in the microcapsule, its content, the composition of the capsule wall film, the film thickness and the coloring state and temperature of the pigment are left and right, but in the microcapsule When the capsule pigment is in a fully colored state and water is used as a reference substance at 20° C., the specific gravity thereof is preferably in the range of 1.05 to 1.20, more preferably 1.10 to 1.20. A particularly preferable range is 1.12 to 1.15. It is easy to maintain the coloring state before and after discoloration, that is, microcapsule pigments with a large hysteresis width ΔH often use component (c) having two or more aromatic rings in the molecule, and have the above-mentioned high specific gravity. When such a pigment is combined with a vehicle described later, although the vehicle has a low viscosity, it is possible to prevent the microcapsule pigment from settling or floating in the ink when it is affected by vibration or the like from the outside due to transportation or the like.

As a reversible thermochromic composition with color memory, specifically, by specifying the complete color development temperature t1 as the temperature obtained only in freezers, cold regions, etc., i.e. -50 ~ 0 ° C, preferably -40 to -5°C, more preferably -30 to -10°C, and the complete decolorization temperature t4 is specified as the friction heat obtained by the friction body and the temperature obtained by the heating body around such as a hair dryer, that is, 45 to 95 °C, preferably in the range of 50 to 90 °C, more preferably in the range of 60 to 80 °C, and specifying the ΔH value as 40 to 100 °C can effectively maintain the color presented under normal conditions (daily life temperature range) .

As mentioned above, the ink composition related to the present invention improves the dispersion stability of the microcapsule pigment by including a polymer coagulant and a dispersant, and it is easy to suppress the sedimentation of the microcapsule pigment in the ink when vibration etc. are applied from the outside , floating, by further including a water-soluble organic solvent to inhibit water evaporation, prevent the specific gravity of the vehicle from changing and maintain good dispersion stability of the microcapsule pigment, and form a polymer coagulant or a polymer coagulant and a dispersant The stabilization of the structure of the loose aggregates makes it easier to further optimize the dispersion stability of the microcapsule pigment, so it is preferable to include these additives. Furthermore, since dispersion stability is further improved by further including a dispersion improver, it is more preferable that the ink composition according to the present invention contains a dispersion improver together with a polymer coagulant and a dispersant.

Further, by containing sulfur-based extreme pressure additives such as 2,5-dimercapto-1,3,4-thiadiazole and/or its salt, thereby even if the pH of ink is acidic or alkaline region, also can suppress The poor dispersion and aggregation of microcapsule pigme...

Abstract

To provide a reversible thermochromic aqueous ink composition that exhibits excellent dispersion stability of a reversible thermochromic microcapsule pigment; and a writing instrument using same. A reversible thermochromic aqueous ink composition that contains: a reversible thermochromic microcapsule pigment which is obtained by microencapsulating a reversible thermochromic composition containing(a) an electron-donating color-developing organic compound, (b) an electron-receiving compound, and (c) a reaction medium that determines the temperature at which a color-developing reaction between the component (a) and the component (b) takes place; and a vehicle that contains water and a specific gravity-adjusting agent selected from the group consisting of oxyacids of group 6 elements having atomic weights of 90-185 and salts thereof.

Application Domain

InksOther pens

Technology Topic

Color reactionPolymer chemistry +3

Image

Examples

Experimental program(12)
Comparison scheme(1)
Effect test(1)

Example Embodiment

[0267] Example 1

[0268] Preparation of microcapsule pigments

[0269] A microcapsule pigment suspension containing a reversible thermochromic composition with color memory was obtained. The reversible thermochromic composition is composed of 3',6'-bis[phenyl(3- Methylphenyl)amino]-spiro[isobenzofuran-1(3H), 9'-[9H]xanthene]-3-one 3.00 parts, 4-4'-[2, as (b) component 2,2-Trifluoro-1-(trifluoromethyl)ethylene)biphenyl 5.00 parts, 4-4'-(2-ethylhexylene)bisphenol 3.00 parts, (c) component cyclohexyl It is composed of 50.00 parts of methyl-4-biphenylacetate.

[0270] The suspension is centrifuged to isolate the microcapsule pigment.

[0271] The average particle size of the microcapsule pigment is 1.9μm, the complete decolorization temperature is 61-62°C, the complete color development temperature is -20°C, and the temperature changes from blue to colorless.

[0272] Preparation of ink composition

[0273] 0.40 parts of a polymer flocculant (hydroxyethyl cellulose, trade name CELLOSIZE EP-09, manufactured by ダウケミカル Japan Co., Ltd.), and 0.40 parts of an acrylic polymer dispersant (trade name: ソルスパース 43000, manufactured by Nippon Luberizer Co., Ltd.) Parts, preservative pyridine-2-thiol 1-oxide, sodium salt (trade name: Somomajin 40%, manufactured by Rongejiben Co., Ltd.) 0.20 part, preservative 3-iodo-2-propynyl butyl carbamate After mixing 0.20 parts of ester (trade name: Ceraikasil 2000, manufactured by Rongyner Co., Ltd.) and 62.80 parts of water, 13.00 parts of sodium polytungstate (trade name: SPT-1, SOMETU) was added as a specific gravity regulator to obtain The vehicle.

[0274] An ink composition was obtained by mixing 23.00 parts of the microcapsule pigment in a fully colored state with the vehicle.

[0275] In addition, the specific gravity of the vehicle was measured at 20°C using water as a reference substance. As a result, the specific gravity was 1.128.

[0276] In addition, the specific gravity of the microcapsule pigment was measured at 20°C. As a result, the specific gravity was 1.13 to 1.14, and the specific gravity of the vehicle was 0.99 to 1.00 times the specific gravity of the microcapsule pigment.

[0277] The viscosity of the ink composition was measured using a BL-type viscometer (product name: TVB-M-type viscometer, L-type rotor, manufactured by Toki Sangyo Co., Ltd.). As a result, it was 9.10 mPa at 20°C and at a rotation speed of 6 rpm. ·S, 7.44 mPa·s at a rotation speed of 12 rpm, and 6.23 mPa·s at 30 rpm.

[0278] In addition, at 20°C, the surface tension of the ink composition was 35.27 mN/m, and the pH was 6.33.

[0279] The production of middle filling writing instruments (refer to Figure 4 )

[0280] The ink composition is impregnated in an ink absorbing body 2 covered with a synthetic resin film of a polyester sliver, and is housed in a cylinder 4 made of polypropylene resin, and is placed at the tip of the cylinder via a fixing member 5 The part was assembled in a connected state with a resin-processed pen body 3 (chisel type) made of polyester fiber, and a pen cap was installed to obtain an intermediate filling type writing instrument 1 (marker pen).

[0281] It is formed by attaching SEBS resin as the friction member 7 to the rear end of the shaft cylinder.

[0282] A blue text (handwriting) is formed by writing on the paper with a marker.

[0283] The handwriting appears blue at room temperature (20°C). If rubbed with a friction body installed at the rear end of the barrel, the handwriting will fade and become colorless. This state is maintained at room temperature and cooled to -20 Below ℃, the original blue color is restored again, and the discoloration behavior is repeated.

Example Embodiment

[0284] Example 2

[0285] Preparation of microcapsule pigments

[0286] A microcapsule pigment suspension containing a reversible thermochromic composition with color memory was obtained. The reversible thermochromic composition is composed of 3',6'-bis[phenyl(3- Methylphenyl)amino]-spiro[isobenzofuran-1(3H), 9'-[9H]xanthene]-3-one 3.00 parts, 4-4'-[2, as (b) component 2,2-Trifluoro-1-(trifluoromethyl)ethylene)biphenol 5.00 parts, 4-4'-(2-ethylhexylene)bisphenol 3.00 parts, (c) component 2- [4-(Phenylmethoxy)phenyl]ethyl decanoate is composed of 50.00 parts.

[0287] The suspension is centrifuged to isolate the microcapsule pigment.

[0288] The average particle size of the microcapsule pigment is 1.9μm, the complete decolorization temperature is 60°C, and the complete color development temperature is -20°C, and changes from blue to colorless by temperature changes.

[0289] Preparation of ink composition

[0290] 0.40 parts of a polymer flocculant (hydroxyethyl cellulose, trade name CELLOSIZE EP-09, manufactured by ダウケミカル Japan Co., Ltd.), and 0.40 parts of an acrylic polymer dispersant (trade name: Solsbes 43000, manufactured by Nippon Luberizer Co., Ltd.) Parts, preservative pyridine-2-thiol 1-oxide, sodium salt (trade name: Somomajin 40%, manufactured by Rongejiben Co., Ltd.) 0.20 part, preservative 3-iodo-2-propynyl butyl carbamate After mixing 0.20 parts of ester (trade name: Ceraikasil 2000, manufactured by Rongyppon Co., Ltd.) and 65.80 parts of water, 10.00 parts of sodium polytungstate (trade name: SPT-1, SOMETU) as a specific gravity regulator was added to obtain it. The vehicle.

[0291] The ink composition was obtained by mixing 23.00 parts of the microcapsule pigment in a fully colored state with the vehicle.

[0292] In addition, the specific gravity of the vehicle was measured at 20°C using water as a reference substance. As a result, the specific gravity was 1.094.

[0293] In addition, the specific gravity of the microcapsule pigment was measured at 20°C. As a result, the specific gravity was 1.08 to 1.09, and the specific gravity of the vehicle was 1.00 to 1.01 times the specific gravity of the microcapsule pigment.

[0294] The viscosity of the ink composition was measured using a BL type viscometer. As a result, it was 8.20 mPa·s at a rotation speed of 6 rpm at 20°C, 6.68 mPa·s at a rotation speed of 12 rpm, and 5.55 mPa at a rotation speed of 30 rpm. ·S.

[0295] In addition, at 20°C, the surface tension of the ink composition was 33.43 mN/m, and the pH was 6.55.

[0296] The production of middle filling writing instruments (refer to Figure 4 )

[0297] Through the same procedure as in Example 1, an intermediate filling type writing instrument (marker pen) was obtained.

[0298] A blue text (handwriting) is formed by writing on the paper with a marker.

[0299] The handwriting appears blue at room temperature (20°C). If rubbed with a friction body installed at the rear end of the barrel, the handwriting will fade and become colorless. This state is maintained at room temperature and cooled to -20 Below ℃, it recolors to the original blue, and the discoloration behavior is reproduced repeatedly.

Example Embodiment

[0300] Example 3

[0301] Preparation of microcapsule pigments

[0302] A microcapsule pigment suspension containing a reversible thermochromic composition with color memory was obtained. The reversible thermochromic composition was composed of 6'-(diphenylamino)-2'- as component (a). [(3-(Trifluoromethyl)phenyl)-(Dipentylamino)-2'-[(3-(Trifluoromethyl)phenyl)amino]-spiro[isobenzofuran-1(3H ), 6.00 parts of 9'-(9H)xanthene]-3-one, 4-4'-[2,2,2-trifluoro-1-(trifluoromethyl)ethylene as component (b) ] 6.00 parts of biphenols, 4.00 parts of 4-4'-(2-ethylhexylene) bisphenols, and 50.00 parts of cyclohexylmethyl-4-biphenyl acetate as the component (c).

[0303] The suspension is centrifuged to isolate the microcapsule pigment.

[0304] The average particle size of the microcapsule pigment is 1.9μm, the complete decolorization temperature is 61-62°C, the complete color development temperature is -20°C, and the temperature changes from green to colorless.

[0305] Preparation of ink composition

[0306] 0.40 parts of a polymer flocculant (hydroxyethyl cellulose, trade name CELLOSIZE EP-09, manufactured by ダウケミカル Japan Co., Ltd.), and 0.40 parts of an acrylic polymer dispersant (trade name: Solsbes 43000, manufactured by Nippon Luberizer Co., Ltd.) Parts, preservative pyridine-2-thiol 1-oxide, sodium salt (trade name: Somomajin 40%, manufactured by Rongejiben Co., Ltd.) 0.20 part, preservative 3-iodo-2-propynyl butyl carbamate After mixing 0.20 parts of ester (trade name: Ceraikasil 2000, manufactured by Rongyner Co., Ltd.) and 60.80 parts of water, 15.00 parts of sodium polytungstate (trade name: SPT-1, SOMETU) as a specific gravity regulator was added to obtain The vehicle.

[0307] The ink composition was obtained by mixing 23.00 parts of the microcapsule pigment in a fully colored state with the vehicle.

[0308] In addition, the specific gravity of the vehicle was measured at 20°C using water as a reference substance. As a result, the specific gravity was 1.138.

[0309] In addition, the specific gravity of the microcapsule pigment was measured at 20°C. As a result, the specific gravity was 1.13 to 1.14, and the specific gravity of the vehicle was 1.00 to 1.01 times the specific gravity of the microcapsule pigment.

[0310] The viscosity of the ink composition was measured using a BL type viscometer. As a result, it was 9.20 mPa·s at a rotation speed of 6 rpm at 20°C, 7.54 mPa·s at a rotation speed of 12 rpm, and 6.36 mPa at a rotation speed of 30 rpm. ·S.

[0311] In addition, at 20°C, the surface tension of the ink composition was 38.01 mN/m, and the pH was 6.12.

[0312] The production of middle filling writing instruments (refer to Figure 5 )

[0313] The ink composition is impregnated in the ink absorbing body 2 covered with a synthetic resin film for polyester comb sliver, and is accommodated in the shaft cylinder 4 formed of polypropylene resin. The marker pen nib 3 (cannonball type) made of polyester fiber was assembled in a connected state, and the cap 6 was attached to obtain a writing instrument 1 (marker pen).

[0314] The SEBS resin as the friction member 7 is installed on the top of the cap.

[0315] A green text (handwriting) is formed by writing on the paper with a marker.

[0316] The handwriting appears green at room temperature (20℃). If rubbed with the friction body installed on the pen cap, the handwriting will fade and become colorless. This state is maintained at room temperature and cooled to below -20℃ to restore The coloring is the original green, and the discoloration behavior is repeated.

PUM

Property	Measurement	Unit
The average particle size	1.9	µm
Surface tension	6.33 ~ 35.27	mN/m
Surface tension	6.55 ~ 33.43	mN/m

Description & Claims & Application Information

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Classification and recommendation of technical efficacy words

good dispersion stability

Reversible thermochromic aqueous ink composition and writing instrument using same

A technology for writing instruments and compositions, applied in writing instruments, household appliances, inks, etc., can solve the problems of easy pigment sedimentation, reduced ink discharge, low viscosity, etc., and achieve the effect of excellent dispersion stability

AI-Extracted Technical Summary

Problems solved by technology

Method used

Abstract

Image

Examples

Example Embodiment

Example Embodiment

Example Embodiment

PUM

Description & Claims & Application Information

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