JP2006123324A - Frictional body, writing utensil equipped with the same and writing utensil set - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a frictional body, with which a first state can be tarnished to a second state by scrubbing without stripping off an image or a holograph formed with a reversible thermally tarnishable ink and, at the same time, which can re-write on a scrubbed portion and has a high endurance even through repeated use, and a writing utensil equipped with the frictional body and a writing utensil set. <P>SOLUTION: This frictional body 1 can tarnish an image formed with the reversible thermally tarnishable ink from its first state to its second state by frictional heat and is made of a styrene-butyrene-styrene copolymer or a styrene-ethylene or a butyrene-styrene copolymer. The frictional body has a shore hardness A according to JIS K 6253 A of at least 55°. The writing utensil 2 builds the reversible thermally tarnishable ink 6 therein and is equipped in at least some part with either one between the frictional bodies 1, which tarnishes the holograph with the writing utensil 2. The writing utensil 1 having at least the reversible thermally tarnishable ink 6 built therein and the writing utensil set equipped with the frictional body 1 tarnishing the holograph through frictional heat are dealt. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a friction body, a writing instrument including the friction body, and a writing instrument set. More specifically, the present invention relates to a friction body that changes an image or a handwriting formed with reversible thermochromic ink from a first state to a second state by frictional heat, a writing instrument including the friction body, and a writing instrument set.

Conventionally, there has been proposed a thermochromic set including a friction body that discolors a reversible thermochromic layer formed on a support with frictional heat generated by manual friction (see Patent Document 1).
The friction body used in the above proposal is provided with an overcoat layer on the reversible thermochromic layer because the reversible thermochromic layer is peeled off when rubbing to generate frictional heat and the reversible color change is impaired. It is necessary to prevent peeling.
Further, in the exemplary resin used in the rubbing portion of the friction body described in Patent Document 1, since the resin itself is scraped by rubbing, a residue may be produced and the surroundings may be soiled. Furthermore, the number of scratches may increase due to the low generation efficiency of frictional heat.
Further, since the reversible thermochromic layer of Patent Document 1 is provided with an overcoat layer for preventing peeling of the rubbing part of the reversible thermochromic image, it is only possible to discolor the existing reversible thermochromic image. The reversible thermochromic image freely formed by the user could not be discolored.

In view of this, silicone rubber has been proposed as a useful friction body for discoloring without peeling off an image or handwriting formed with reversible thermochromic ink without requiring a protective member such as an overcoat layer (Patent Document 2). reference).
The silicone rubber can be discolored without peeling off the image or handwriting formed by the reversible thermochromic ink, and can exhibit excellent effects as a friction body due to high generation efficiency of frictional heat.
However, when the handwriting or image is rubbed and discolored, the silicone rubber slightly adheres to the rubbed portion, so that even if writing is performed again on the rubbed portion, the ink will repel and form a handwriting or image. It was difficult to do.
JP-A-7-241388 JP 2004-148744 A

  The present invention solves the above-mentioned problems, and it is possible to change the color from the first state to the second state by rubbing without peeling off the image or handwriting formed by the reversible thermochromic ink, It is possible to provide a friction body that can be written and has high durability by repeated use. Furthermore, the present invention provides a writing instrument provided with a friction body and a writing instrument set including the friction body and the writing instrument, which can discolor an image formed freely with reversible thermochromic ink.

The present invention is a friction body that changes an image formed using reversible thermochromic ink from a first state to a second state by frictional heat, wherein the friction body is a styrene-butylene-styrene copolymer or It is required to be composed of a styrene-ethylene / butylene-styrene copolymer. Further, the friction body has a shore hardness A of 55 degrees or more in JIS K6253A, the friction body contains a colorant, and the colorant contains 0.1 to 1.0% by weight in the total amount of the friction body. It is necessary to be done.
Furthermore, a writing instrument incorporating reversible thermochromic ink, comprising at least a part of any one of the friction bodies that changes the handwriting formed by the writing instrument from the first state to the second state by frictional heat. Requirement. Furthermore, the friction body and the writing instrument body or the writing instrument member are integrally formed by two-color molding, the friction body is fitted to the writing instrument, and the friction body is a writing instrument member. .
Furthermore, a writing instrument set comprising at least a writing instrument containing a reversible thermochromic ink and any of the friction bodies that change the handwriting formed by the writing instrument from the first state to the second state by frictional heat is a requirement. .
Further, the reversible thermochromic ink contains a microcapsule pigment having a high temperature side color change point in a range of at least 25 ° C. to 95 ° C., and the reversible thermochromic ink is decolored by heating from a colored state. Heat decoloring type, color memory holding type that changes and holds the colored state or decolored state in a specific temperature range, or color development by heating from the decolored state, and restoration to the decolored state by cooling from the colored state Any one of them, or any combination thereof, and the color of the reversible thermochromic ink is colored in either the first state or the second state, and the other is It must be colorless.

  According to the first aspect of the present invention, there can be obtained a friction body capable of easily changing the color without peeling off the thermochromic image and forming a thermochromic image again on the rubbing portion without causing ink repelling.

  According to the second aspect, the generation efficiency of the frictional heat can be increased without fouling the periphery of the scraped portion by scraping during scraping.

  According to the third aspect of the present invention, it is possible to form a friction body having a good design.

  According to the fourth aspect, the friction body is clearly colored, and the thermochromic image can be discolored without being transferred to the thermochromic image and its peripheral portion at the time of rubbing.

  According to the fifth aspect, the user can freely form an image, and the image can be easily discolored by using a friction body provided in the writing instrument.

  According to the sixth to eighth aspects, the friction body can be reliably provided to the writing instrument without dropping off.

  According to the ninth aspect, the user can freely form an image, and the image can be easily changed in color by using a friction body provided therewith.

  According to the tenth aspect, the ink has a high color density and is surely discolored by rubbing.

  According to the eleventh aspect, it is possible to form a magic-rich image that is reversibly discolored by heating and cooling, and various applications such as learning, teaching, and toy elements can be applied according to the purpose.

  According to the twelfth aspect, when another image is formed again on the decolored image, the visually recognized images are prevented from overlapping.

  The friction body of the present invention is for easily changing the color or the image formed by means of printing, writing or the like with reversible thermochromic ink from the first state to the second state by frictional heat. By rubbing, the color is changed to a color different from the normal state.

In addition, since the friction body of the present invention can be heated by manual operation without using power or the like, it can be manufactured at a low cost without requiring a large-scale device, so that the shaft cylinder of a writing instrument incorporating reversible thermochromic ink can be used. Provided by means such as fitting or two-color molding at the rear end or the top of the writing instrument cap, etc., or used in conjunction with a writing instrument incorporating reversible thermochromic ink, or equipped with a reversible thermochromic ink printing image Can be used in conjunction with picture books and toys.
In particular, when the writing instrument and the friction body are provided separately to form a reversible thermochromic writing instrument set, or when the writing instrument is provided with a friction body, a free image can be formed by the writing instrument, and the friction body Since the image can be easily changed in color, it becomes more useful.

  As the friction body, a styrene-butylene-styrene (SBS) copolymer or a styrene-ethylene-butylene-styrene (SEBS) copolymer is applied. These copolymers have good generation efficiency of frictional heat, can be repeatedly and reversibly discolored without peeling off the thermochromic image, and can be smoothly rubbed because of low resistance during rubbing, Even if it is fixed to the support during rubbing, ink repelling does not occur, so it is possible to rewrite the rubbing portion.

Moreover, it is preferable that the hardness of the friction body made of the copolymer is 55 degrees or more in Shore hardness A in JIS K6253A.
By setting the temperature to 55 degrees or more, the generation efficiency of frictional heat is increased and the frictional body is less likely to be scraped off. Therefore, the thermochromic image can be easily discolored with a small number of scratches, and the periphery of the scraped portion can be removed by scraping scraps. Can be used without getting dirty.
In order to give elasticity to the friction body, it is preferable to set the Shore hardness A to 100 degrees or less. By setting it to 100 degrees or less, since an elastic force is provided, the contact surface with the support during friction increases, and the thermochromic image can be easily discolored with a small number of scratches and can be smoothly scratched.

Furthermore, a colorant can be added to the friction body. By coloring the friction body, it becomes rich in design. In addition, when the friction body is mounted on a writing instrument, it is colored in the ink color of the first state or the second state, and is used as a color display function part that informs the user of the color that appears due to the color of the first state or discoloration. The design can be unified by coloring according to the exterior.
The amount of the colorant added is preferably 0.1 to 1.0% by weight based on the total amount of the friction body. If it is 0.1% or less, the friction body cannot be clearly colored, and if it is more than 1.0%, the colorant may transfer around the handwriting when it is rubbed.
In general, general-purpose dyes, pigments, and the like can be appropriately used as the colorant.
Furthermore, various additives such as a filler can be added to the friction body as necessary.

In the friction body, the shape of the rubbing portion can be a convex curved surface. In particular, in a friction body attached to a writing instrument, the friction body is small, and therefore, the shape of the rubbing portion is preferably a convex curved surface. By using a convex curved surface, it can be rubbed with moderate softness without peeling off the handwriting. In addition, a constant contact area can be obtained regardless of the contact angle with the handwriting, and only the target part can be abraded without rubbing a wide area, the wearability of the friction body itself can be reduced, and the heat generation efficiency is increased. For this reason, it is difficult to remove scraps and the color to be changed can be accurately and easily changed.
Furthermore, in the friction body attached to the writing instrument, it is preferable to set the radius of curvature of the convex curved surface in a range of 1 mm to 10 mm. By setting it as the said range, the narrow handwriting formed with a writing instrument can be discolored exactly and easily.

When the friction body is attached to the writing instrument, it can be attached by fitting a molded object made of a separate member to the writing instrument, or integrally forming the writing instrument body or the writing instrument member by two-color molding. In the case of fitting as a separate member, the number of parts can be reduced by forming the friction body in the shape of a writing instrument member such as a head crown and a tail plug and directly configuring the writing instrument.
Moreover, since the said copolymer is excellent in a moldability, a friction body can be easily provided by carrying out two-color molding with a writing instrument main body and a writing instrument member.

Furthermore, by setting the removal force of the friction body for writing instruments to be fitted to 10 N or more, it becomes impossible to easily remove the friction body from the writing instruments, and it is possible to prevent accidental ingestion by an infant or the like. When attaching a friction body to the writing instrument, a locking rib can be provided on the inner surface of the friction body fitting portion of the writing instrument for the purpose of improving the pulling force.
Further, when a friction body is provided on the writing instrument, by providing a ventilation hole or a ventilation groove in the friction body, even if an infant or the like swallows it, the safety becomes higher.

Next, the reversible thermochromic ink will be described.
The reversible thermochromic ink that forms a reversible thermochromic image and handwriting reversibly discolored by the friction body of the present invention is a heat decoloring type that decolorizes by heating from a colored state, a colored state or a decolored state. Various types are used alone or in combination, such as a color memory retention type that memorizes and retains in a specific temperature range, or a heat coloring type that develops color by heating from a decolored state and returns to a decolored state by cooling from the colored state. Can be configured. By using the above configuration, it is possible to form an image rich in magic, such as an image in which the color changed by rubbing returns to the original color instantly, or an image in which discoloration due to rubbing can be maintained in a wide temperature range.
The reversible thermochromic ink has a low temperature side color change point in the range of -30 ° C to + 10 ° C and a high temperature side color change point in the range of 25 ° C to 95 ° C (preferably 36 ° C to 90 ° C). Accordingly, it is possible to effectively maintain the color exhibited in the normal state (daily life temperature range), and it is possible to change the color by rubbing with the friction body of the present invention, so that the practicality is high.

The reversible thermochromic microcapsule pigment contained in the reversible thermochromic ink is conventionally known (a) electron donating color-forming organic compound, (b) electron accepting compound, and (c) the above It is effective to encapsulate a reversible thermochromic composition containing at least the essential three components of a reaction medium that determines the temperature at which the color reaction of both occurs in a microcapsule. As the decoloring type, those described in Japanese Patent Publication No. 51-44706, Japanese Patent Publication No. 51-44707, Japanese Patent Publication No. 1-292998, etc. proposed by the present applicant can be used. The color changes before and after a predetermined temperature (discoloration point), exhibits a decolored state in a temperature range above the complete decoloring temperature, and develops a color state in a temperature range below the complete color developing temperature. There is only one specific state in the region. That is, the other state is maintained while the heat or cold necessary to develop the state is applied, but when the heat or cold is not applied, the state returns to the state exhibited in the normal temperature range. The width is relatively small (ΔH = 1 to 7 ° C.).
In a system in which ΔH is 3 ° C. or lower (a system in which a fatty acid ester having a ΔT value (melting point-cloud point) of 3 ° C. or lower shown in JP-B-1-29398 is applied as a discoloration temperature adjusting compound) Sensitive to temperature changes at the decoloring temperature (t ₄ ) and complete color development temperature (t ₁ ), showing high-sensitivity discoloration. In systems where ΔH is about 4-7 ° C, the original color is slowly changed after discoloration. It is possible to improve the visual recognition effect.
In addition, the large hysteresis characteristics (ΔH = 8 to 50 ° C.), that is, the shape of the curve in which the change of the color density due to the temperature is plotted is opposite to the case where the temperature is raised from the lower temperature side than the color change temperature range, from the higher temperature side than the color change temperature range. The color changes by following a path that is largely different from that when the color is lowered, and the color develops in the low temperature range below the complete color development temperature (t ₁ ) or the color erase state in the high temperature range above the complete color erase temperature (t ₄ ). However, a color memory retention type thermochromic composition capable of storing and retaining in a specific temperature range [temperature range between t _{2 and} t ₃ (substantially two-phase retention temperature range)] can also be applied. Furthermore, by using an ester compound composed of an alcohol compound having two aromatic rings in the molecule such as 4-benzyloxyphenylethyl caprate and a saturated or unsaturated fatty acid having 4 or more carbon atoms, as the component (c). Also, a color memory retaining thermochromic composition exhibiting greater hysteresis characteristics (ΔH = 50 to 80 ° C.) can be applied.
The substantial two-phase holding temperature range can be set according to the purpose, but in the present invention, the high temperature side discoloration point is set in a range of 25 ° C to 95 ° C (preferably 36 ° C to 90 ° C).
Incidentally, the low-temperature side color change point [complete coloring temperature (t _1)] is, -30 ℃ ~ + 20 ℃ (preferably, -30 ℃ ~ + 10 ℃) can be set to any temperature selected from the range of.
By the temperature setting, the color development state or the color erasure state can be stored in an alternating manner at any temperature between the color development start temperature (t ₂ ) and the color erasure start temperature (t ₃ ) and can be visualized.
Further, as a heat-colorable composition, a specific color having a linear or side chain alkyl group having 3 to 18 carbon atoms as an electron-accepting compound proposed by the present applicant, which develops color when heated from a decolored state. A system to which an alkoxyphenol compound is applied (JP-A-11-129623, JP-A-11-5973) or a system to which a specific hydroxybenzoic acid ester is applied (JP-A-2001-105732), and further decoloring A system using a gallic acid ester or the like that develops color at a high temperature side discoloration point (complete color development temperature) by heating from the state can be applied.
Here, a colorant such as a non-thermochromic dye or pigment is blended in the reversible thermochromic microcapsule or the ink so as to change the color from color (1) to color (2). It can be configured to present.

  The microcapsule pigment has an average particle diameter in the range of 0.5 to 5.0 μm, preferably 1 to 4 μm. When the average particle size exceeds 5.0 μm, the outflow from the capillary gap of the ball-point pen tip or the marking pen tip decreases, and when the average particle size is 0.5 μm or less, it is difficult to show high density color development. Become.

  The reversible thermochromic microcapsule pigment can be blended in an amount of 2 to 50% by weight (preferably 3 to 40% by weight, more preferably 4 to 30% by weight) based on the total amount of the ink composition. If it is less than 2% by weight, the color density is insufficient, and if it exceeds 50% by weight, the ink outflow is reduced and the writing property is impaired.

The form of the capsule in the reversible thermochromic microcapsule pigment of the present invention does not refuse application of a circular cross-sectional form, but a non-circular cross-sectional form is effective.
The reversible thermochromic handwriting formed by writing has the above-mentioned microcapsule pigment closely oriented and fixed in close contact with the writing surface on the long diameter side (maximum outer diameter side). The microcapsule pigment is slightly elastically deformed into a shape that relaxes the external force against external force caused by rubbing the handwriting with a friction body, and the destruction of the wall film of the microcapsule is suppressed and the thermochromic function is impaired. It can be effectively expressed without.
Here, the non-circular cross-sectional shape microcapsule pigment preferably has an average value of maximum outer diameters in the range of 0.5 to 5.0 μm.
The microcapsule pigments (including those having a circular cross-sectional shape) exhibit a decrease in the ability to flow out from the capillary gap when the average maximum outer diameter exceeds 5.0 μm, while the average maximum outer diameter In a system having a value of 0.5 μm or less, it is difficult to show coloration at a high concentration. Preferably, the average value of the maximum outer diameter is in the range of 1 to 4 μm, and the average particle diameter of the microcapsule The minimum outer diameter) / 2] is preferably in the range of 1 to 3 μm.

  For the microencapsulation of the reversible thermochromic composition, known means such as an interfacial polymerization method, an interfacial polycondensation method, an in situ polymerization method, and a coacervate method can be applied, but the particle size range satisfying the above-described requirements of the present invention In order to obtain the microcapsule pigment, it is effective to apply an interfacial polymerization method or an interfacial polycondensation method which hardly causes aggregation and coalescence.

Further, in the reversible thermochromic microcapsule pigment or ink, a colorant such as a non-thermochromic dye or pigment is blended to change the color from color (1) to color (2). It can also be set as the structure which exhibits a change.
As the dye, acid dyes, basic dyes, direct dyes, and fluorescent dyes can all be used. Examples of pigments include inorganic pigments such as carbon black, ultramarine, and titanium dioxide pigments, azo pigments, phthalocyanine pigments, indigo pigments, thioindigo pigments, selenium pigments, quinacridone pigments, anthraquinone pigments, stron pigments, diketo Examples thereof include organic pigments and fluorescent pigments such as pyrrolopyrrole pigments, dioxazine pigments, perylene pigments, perinone pigments, and isoindolinone pigments.

The reversible thermochromic ink incorporated in a writing instrument provided with the friction body of the present invention or a writing instrument provided separately from the friction body as a writing instrument set has a high temperature side color change point in the range of 25 to 95 ° C. It is effective to disperse a reversible thermochromic microcapsule pigment having a particle diameter in the range of 0.5 to 5 μm in an aqueous medium and blend a binder resin as necessary.
Specifically, a shear-thinning ink containing a shear-thinning substance and an agglomerated ink in which a reversible thermochromic microcapsule pigment is suspended in a gentle agglomerated state with a water-soluble polymer flocculant are effective. . Furthermore, a specific gravity control type ink in which the reversible thermochromic microcapsule pigment is adjusted to have a specific gravity difference of 0.05 or less with respect to the aqueous vehicle can also be applied.

  The shear thinning substance is a nonionic surfactant having an HLB value in the range of 8 to 12, xanthan gum, welan gum, succinoglycan whose constituent monosaccharide is an organic acid-modified heteropolysaccharide of glucose and galactose (average molecular weight of about 1 to 8 million), guar gum, locust bean gum and derivatives thereof, hydroxyethyl cellulose, alginic acid alkyl esters, polymers having a molecular weight of 100,000 to 150,000 based on alkyl esters of methacrylic acid, glucomannan, agar and carrageenan Examples include carbohydrates having gelling ability extracted from seaweed such as benzylidene sorbitol and benzylidene xylitol or their derivatives, crosslinkable acrylic acid polymers, and the like, which can be used alone or in combination. Xanthan gum, succinoglycan, and crosslinkable acrylic acid polymer are particularly excellent in storage stability.

As the water-soluble polymer flocculant, a nonionic water-soluble polymer compound is preferably used.
Specific examples include polyvinyl pyrrolidone, polyethylene oxide, water-soluble polysaccharides, nonionic water-soluble cellulose derivatives, and the like. Among these, specific examples of water-soluble polysaccharides include tragacanth gum, guar gum, pullulan, cyclodextrin, and specific examples of nonionic water-soluble cellulose derivatives include methylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, hydroxyethylmethylcellulose, Examples thereof include hydroxypropylmethylcellulose. Any water-soluble polymer exhibiting a loose bridging action between the microcapsule pigment particles in the reversible thermochromic water-based ink composition of the present invention can be applied, and in particular, the nonionic water-soluble cellulose described above. The derivatives most effectively act on the reversible thermochromic aqueous ink composition of the present invention.
The polymer flocculant can be blended in an amount of 0.05 to 20% by weight based on the total amount of the ink composition.

Further, as a moisturizing agent to suppress drying at the nib, glycols such as glycerin, propylene glycol, ethylene glycol, diethylene glycol, and low molecular weight polyethylene glycol and their lower alkyl ethers, 2-pyrrolidone, N-vinylpyrrolidone, An appropriate amount of urea or the like can be blended.
The humectant can be blended in an amount of 5 to 40% by weight based on the total amount of ink.

Furthermore, an appropriate amount of a binder resin can be added to adjust the stickiness of the handwriting and the viscosity. The binder resin is selected from a resin emulsion, an alkali-soluble resin, and a water-soluble resin.
Examples of the resin emulsion include polyacrylic acid ester, styrene-acrylic acid copolymer, polyvinyl acetate, ethylene-vinyl acetate copolymer, ethylene-vinyl chloride copolymer, methacrylic acid-maleic acid copolymer, ethylene- Examples include aqueous dispersions such as methacrylic acid copolymers, α-olefin-maleic acid copolymers, polyesters, and polyurethanes. Examples of the alkali-soluble resins include styrene-maleic acid copolymers and ethylene-maleic acid copolymers. , Styrene-acrylic acid copolymer, and the like. Examples of the water-soluble resin include polyvinyl alcohol and polyvinyl butyral, and one or a mixture of two or more can be used.
Moreover, conventionally various various dispersing agents, such as surfactant, can be mix | blended as needed.

  When the ink composition of the present invention is used by filling a ballpoint pen, a higher fatty acid such as oleic acid, a nonionic surfactant having a long chain alkyl group, a polyether-modified silicone oil, a thiophosphorous acid tri (alkoxycarbonylmethyl ester) ) And thiophosphite triester (alkoxycarbonylethyl ester), etc., polyoxyethylene alkyl ether or polyoxyethylene alkyl aryl ether phosphate monoester, polyoxyethylene alkyl ether or polyoxyethylene alkyl aryl ether It is preferable to add a lubricant such as a phosphoric acid diester or a metal salt, an ammonium salt, an amine salt, an alkanolamine salt thereof to give the ball seat an antiwear effect.

The shear-thinning ink and the aggregation ink are filled in a general-purpose writing instrument for practical use.
Specifically, the shear-thinning ink is filled in a shaft cylinder having a tip that rotatably holds a ball at the tip, and a viscous follower (liquid stopper) is disposed at the rear to form a ballpoint pen. The thermochromic writing instrument can be constructed. In addition, agglomerated ink has a large number of fibers arranged in close contact with each other, a fiber processed body in which capillary gaps are formed between adjacent fibers is used as a pen, and capillary gaps are formed between adjacent fibers. The marker-shaped thermochromic writing instrument can be formed by impregnating the aggregated ink into a marker assembled with the fiber bundling body as an ink occlusion body and the rear end of the pen body connected to the front end of the ink occlusion body.

  In addition, when using the friction body of this invention with a writing instrument, it is a tautomer from a color to a colorless or a colorless to a color rather than the structure which exhibits a tautomatic color change from a color (1) to a color (2) by abrasion. By adopting a configuration that exhibits color change and rewriting on the handwriting in a colorless state, it can be used as if it were newly written.

Examples are shown below, but the present invention is not limited to these examples. In addition, the part in an Example is a weight part.
FIG. 1 shows an embodiment of a writing instrument, and FIG. 2 shows a color change behavior diagram of a heat-erasable thermochromic ink.

Example 1
Preparation of friction body Add 0.25 part of blue pigment [Daiichi Seika Kogyo Co., Ltd.] to 100 parts of SEBS copolymer elastomer [Aron Kasei Co., Ltd., trade name: AR-885C, Shore A hardness: 88] After kneading, the blue friction body 1 was obtained by molding.
The friction body 1 can instantly change the color of the reversible thermochromic image printed on the paper surface by rubbing, and the color of the friction body 1 does not transfer to the paper surface.

Example 2
Preparation of friction body 0.125 part of blue pigment [Daiichi Seika Kogyo Co., Ltd.] and 0.125 part of pink pigment [Daiichi Seika Kogyo Co., Ltd.] SBS copolymer elastomer [Aron Kasei Co., Ltd. Trade name: AR-460, Shore A hardness: 60] After adding to 100 parts, kneading and molding, purple friction body 1 was obtained.
The friction body 1 can instantly change the color of the reversible thermochromic image printed on the paper surface by rubbing, and the color of the friction body 1 does not transfer to the paper surface.

Example 3
Preparation of thermosensitive color-changing color memory microcapsule pigment (a) As component (3- (4-diethylamino-2-hexyloxyphenyl) -3- (1-ethyl-2-methylindol-3-yl) -4- 2.0 parts of azaphthalide, 8.0 parts of bis (3-methyl-4-hydroxyphenyl) sulfide as component (b), 5.0 parts of 2,2-bis (4′-hydroxyphenyl) hexafluoropropane, ) A temperature-sensitive color-changing color memory composition comprising 50.0 parts of 4-benzyloxyphenylethyl caprate as a component is uniformly heated and dissolved, and 30.0 parts of an aromatic polyvalent isocyanate prepolymer as a wall film material, A solution in which 40.0 parts of the co-solvent is mixed is emulsified and dispersed in 8% polyvinyl alcohol aqueous solution so as to form fine droplets, followed by stirring at 70 ° C. for about 1 hour. 2.5 parts of an aliphatically modified amine was added, and stirring was further continued for 6 hours to obtain a temperature-sensitive color-changing color memory microcapsule pigment suspension.
The suspension was centrifuged to isolate a thermochromic color memory microcapsule pigment.
The hysteresis width (ΔH) of the microcapsule pigment (t ₁ : −14 ° C., t ₂ : −6 ° C., t ₃ : 48 ° C., t ₄ : 60 ° C., average particle size: 2 μm) is 64 ° C. When the temperature changes, the color changes from blue to colorless.

Preparation of temperature-sensitive color-change color memory ink 25.7 parts of the above microcapsule pigment, 0.2 part of succinoglycan (shear thinning agent), 5.5 parts of urea, 7.5 parts of glycerin, nonionic permeability Giving agent [manufactured by San Nopco Co., Ltd., trade name: Nopco SW-WET-366] 0.03 part, modified silicone antifoaming agent [manufactured by Nippon Silicone Co., Ltd., trade name: FS Antifoam 013B] 0.15 Part, antiseptic [manufactured by Zeneca Co., Ltd., trade name: Proxel XL-2] 0.1 part, lubricant [Daiichi Kogyo Seiyaku Co., Ltd., Prisurf A212C] 0.5 part, triethanolamine 0.5 A temperature-sensitive color-changing color memory ink 6 consisting of 59.82 parts of water was prepared.

Preparation of writing instrument 0.97 g of the ink 6 (previously cooled to -14 ° C. or less to develop a blue color of the microcapsule pigment and allowed to stand at room temperature) into a polypropylene pipe having an inner diameter of 4.4 mm is sucked and filled. The ballpoint pen tip 4 was connected via a resin holder.
Next, from the rear part of the polypropylene pipe (refill pipe 8) is filled with a viscoelastic ink backflow prevention body (liquid stopper 7) mainly composed of polybutene, and a tail plug is fitted to the rear part of the refill pipe 8. Then, after attaching the shaft cylinder 5 composed of the front shaft and the rear shaft and fitting the cap 3, the ball pen 2 was obtained by performing a deaeration process by a centrifugal process.
The ballpoint pen tip 4 has a tip of the metal pipe that is pressed and deformed inwardly from the outer surface to hold a stainless steel ball having a diameter of 0.7 mm. The rubbing part 11 of the friction body 1 obtained in Example 1 is formed into a convex curved surface with a curvature radius of 3.0 mm and fitted with a pulling force of 10 N (FIG. 1).

Discoloration behavior of handwriting The thermochromic handwriting written on paper with normal penetrability by the ballpoint pen 2 is in a blue color development state at room temperature (25 ° C), the low temperature side discoloration point (-6 ° C) or higher, the high temperature side This state was maintained at a temperature below the discoloration point (60 ° C.).
When the handwriting was rubbed several times with the friction body 1 fixed to the cap, the rubbed portion was immediately decolored to become colorless and had a low temperature side discoloration point (−6 ° C.) or more and a high temperature side discoloration point (60 ° C.) or less. This state was maintained at temperature.
Next, when the thermochromic handwriting was left in a freezer (about −15 ° C.), the decolored portion developed blue again and returned to the state before rubbing. This discoloration behavior could be reproduced repeatedly.
Furthermore, even if rewriting is performed on a portion erased by rubbing, it was possible to form a handwriting without causing the handwriting to repel. The rubbing erasure and handwriting formation on the erased part could be repeated.

Example 4
Preparation of reversible thermochromic ink Reversible thermochromic pigment (t ₁ : 3 ° C., t ₂ : 6 ° C., t ₃ : 38 ° C., t ₄ : 45) in which a thermosensitive color-changing color memory composition is encapsulated in a microcapsule. ° C, average particle size: 2.5 µm, ΔH = 37 ° C, color changes from blue to colorless) 18 parts, xanthan gum (shear thinning agent) 0.33 parts, urea 10 parts, glycerin 10 parts, nonionic penetration 0.6 part of property imparting agent [manufactured by San Nopco Co., Ltd., trade name: Nopco SW-WET-366], 0.1 part of modified silicone antifoaming agent [manufactured by San Nopco Co., Ltd., trade name: Nopco 8034], prevention A reversible thermochromic ink 6 comprising 0.1 part of glaze [manufactured by Zeneca Corporation, trade name: Proxel XL-2] and 60.87 parts of water was prepared.

Preparation of a writing instrument 0.97 g of the ink 6 (cooled to 2 ° C. or less in advance to develop a reversible thermochromic pigment and then allowed to stand at room temperature) into a polypropylene pipe having an inner diameter of 4.4 mm, It connected with the ball-point pen tip 4 through the resin holder. The ball-point pen tip 4 is formed by holding a stainless steel ball having a diameter of 0.7 mm at the tip of a tip obtained by pressing and deforming the vicinity of the tip of a metal pipe inward from the outer surface. It is biased forward by a spring body.
Next, from the rear part of the polypropylene pipe (refill pipe 8), an ink backflow prevention body (liquid stopper 7) having a viscoelasticity mainly composed of polybutene is filled and assembled in the shaft cylinder 5, and prepared in Example 2. The rubbing portion 11 of the friction body 1 is a convex curved surface having a curvature radius of 3.0 mm, and after attaching the cap 3 fitted to the fitting portion 31 with a removal force of 10 N, the deaeration treatment is performed by centrifugal treatment, and shearing A thinning thermochromic ballpoint pen 2 was obtained (FIG. 1).
When writing on the report paper with the ballpoint pen 2, the handwriting was not erased even by writing for a long time or shorthand, and a clear thermochromic handwriting of blue having a stable density was obtained.

Discoloration behavior of handwriting The thermochromic handwriting written on paper having normal penetrability with the ballpoint pen 2 is in a blue color development state at room temperature (25 ° C.), and when it was rubbed several times with the friction body 1, it was rubbed. The part immediately changed color and became colorless, and this state could be maintained at room temperature. Next, when the thermochromic handwriting was left in a freezer (about −15 ° C.), the decolored portion developed blue again and returned to the state before rubbing. This discoloration behavior could be reproduced repeatedly.
Furthermore, even if rewriting is performed on a portion erased by rubbing, it was possible to form a handwriting without causing the handwriting to repel. The rubbing erasure and handwriting formation on the erased part could be repeated.

Example 5
Preparation of reversible thermochromic ink Heat erasable reversible thermochromic microcapsule pigment (t ₁ : 35 ° C., t ₂ : 38 ° C., t ₃ : 37 ° C., t ₄ : 40 ° C., average particle size: 2.5 μm , ΔH = 2 ° C., 44.0 parts of the microcapsule slurry (changing from blue to colorless color) (solid content: 13.2%) was added to a pink dye [Eisen Hodogaya Co., Ltd., trade name: Erythrosin (C I. No. 45430)] 0.5 part, glycerin 5.0 part, antifungal agent, [Zeneca Co., Ltd., trade name: Proxel XL-2] 0.70 part, silicone-based antifoaming agent, [ Product name: SN deformer 381] manufactured by San Nopco Co., Ltd. After being uniformly dispersed in an aqueous medium comprising 0.1 part and 41.7 parts of water, a water-soluble polymer flocculant (hydroxyethyl cellulose) [ Product name: Union Carbide Japan Co., Ltd. (ROSIZE WP-09L) 8.0 parts by weight of an aqueous solution containing 5.0% by weight is added to the dispersed liquid while stirring to suspend the reversibly thermochromic microcapsule pigment in a loosely aggregated state. A reversible thermochromic ink 6 was prepared.

Preparation of writing instrument A fiber sizing ink occlusion body (porosity of about 80%) covered with a polyester resin sliver is impregnated with the reversible thermochromic ink 6 immediately after being uniformly stirred, and the tip of the shaft cylinder A water-based marker was constructed by assembling a polyester fiber resin processing pen body (porosity of about 50%) in contact with the part.
Furthermore, the friction body 1 created in Example 1 was a cube having a side of 20 mm, and a writing instrument set was obtained together with the obtained marker.
When writing on the report paper with the water-based marker, the handwriting was not discolored even with long-time writing or shorthand writing, and a clear, clear purple-colored handwriting with a stable color tone was obtained.

Discoloration behavior of handwriting The handwriting written on paper having normal penetrability with the water-based marker is in a purple discoloration state at room temperature (25 ° C.). The color changed to pink. Further, when left in this discolored state at room temperature, the pink color portion changed to purple again and returned to the state before rubbing. The discoloration behavior could be reproduced repeatedly.
In addition, even if rewriting was performed on the scraped portion, it was possible to form handwriting without causing handwriting repelling or the like. The scratch discoloration and handwriting formation on the discolored portion could be repeated.

Example 6
Preparation of temperature-sensitive color-changing color-memory microcapsule pigment (i) 4.5 parts by weight of 2- (2-chloroanilino) -6-di-n-butylaminofluorane as component (1,) 1,1- Bis (4'-hydroxyphenyl) n-decane 4.5 parts by weight, 2,2-bis (4'-hydroxyphenyl) hexafluoropropane 7.5 parts by weight, (c) 4-benzyloxyphenyl caprate as component A temperature-sensitive color-changing color memory composition comprising 50.0 parts by weight of ethyl is uniformly heated and dissolved, and 30.0 parts by weight of an aromatic polyvalent isocyanate prepolymer and 40.0 parts by weight of a co-solvent are used as wall film materials. The mixed solution is emulsified and dispersed in 8% aqueous polyvinyl alcohol solution so as to form fine droplets. After stirring at 70 ° C. for about 1 hour, 2.5 parts by weight of a water-soluble aliphatic modified amine is added. Stirring was continued for 6 hours to obtain a temperature-sensitive color-change color-memory microcapsule pigment suspension.
The suspension was centrifuged to isolate a thermochromic color memory microcapsule pigment.
The hysteresis width (ΔH) of the microcapsule pigment (t ₁ : −20 ° C., t ₂ : −9 ° C., t ₃ : 40 ° C., t ₄ : 57 ° C., average particle size: 2.5 μm) is 63 ° C. The color changes from black to colorless with temperature change.

Preparation of temperature-sensitive color-changing color memory ink 25.7 parts by weight of the microcapsule pigment, 0.2 parts by weight of succinoglycan (shear thinning agent), 5.5 parts by weight of urea, 7.5 parts by weight of glycerin, Nonionic permeability imparting agent [manufactured by San Nopco Co., Ltd., trade name: Nopco SW-WET-366] 0.03 parts by weight, modified silicone antifoaming agent [manufactured by Nippon Silicone Co., Ltd., trade name: FS Antifoam 013B] 0.15 parts by weight, preservative [Zeneca Co., Ltd., trade name: Proxel XL-2] 0.1 parts, lubricant [Daiichi Kogyo Seiyaku Co., Ltd., Prisurf A212C] 0.5 weight Part, 0.5 parts by weight of triethanolamine, and 59.82 parts by weight of water were prepared.

Preparation of writing instrument 0.97 g of the ink 6 (cooled to -20 ° C. or less in advance and allowed to stand at room temperature after coloring the microcapsule pigment in black) was sucked and filled into a polypropylene pipe having an inner diameter of 4.4 mm. The ballpoint pen tip 4 was connected via a resin holder.
Next, from the rear part of the polypropylene pipe (refill pipe 8) is filled with a viscoelastic ink backflow prevention body (liquid stopper 7) mainly composed of polybutene, and a tail plug is fitted to the rear part of the refill pipe 8. Then, the front shaft cylinder and the rear shaft cylinder were assembled, and after the cap 3 was fitted, a deaeration process was performed by a centrifugal process to obtain a ballpoint pen 2.
The cap 3 is a cap body made of polypropylene resin, using a SEBS copolymer elastomer [Aron Kasei Co., Ltd., trade name: AR-885C, Shore A hardness: 88], and a cap portion by two-color molding. The ballpoint pen tip 4 is made of stainless steel having a diameter of 1.0 mm at the tip end of the tip of the metal pipe that is pressed and deformed inward from the outer surface. A ball is held and the ball is biased forward by a spring body.

Discoloration behavior of handwriting The thermochromic handwriting written on paper having normal penetrability with the ballpoint pen 2 is in a black colored state at room temperature (25 ° C), and completely discolored at a color development start temperature (-9 ° C) or higher. This state was maintained at a temperature of 57 ° C. or lower.
When the handwriting was rubbed several times with the friction body 1 provided on the cap, the rubbed portion was immediately decolored to become colorless and a temperature not lower than the color development start temperature (−9 ° C.) and not higher than the complete erasing temperature (57 ° C.). I kept this state.
Subsequently, when the thermochromic handwriting was left in a freezer (about −15 ° C.), the decolored portion was colored black again and returned to the state before rubbing. This discoloration behavior could be reproduced repeatedly.
Furthermore, even if rewriting is performed on a portion erased by rubbing, it was possible to form a handwriting without causing the handwriting to repel. The rubbing erasure and handwriting formation on the erased part could be repeated.

It is a longitudinal cross-sectional view which shows one Example of the writing instrument provided with the friction body of this invention. It is explanatory drawing which shows the discoloration behavior of a heat decoloring type reversible thermochromic ink.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Friction body 11 Abrasion part 2 Ball-point pen 3 Cap 31 Fitting part 4 Ball-point pen tip 5 Shaft cylinder 6 Thermochromic ink 7 Liquid stopper 8 Refill pipe
t ₁ Full color temperature (low temperature side discoloration point) of heat decoloring type thermochromic ink and color memory retention type thermochromic ink
t ₂ Coloring start temperature of heat-erasable color-changing ink and color memory retention-type thermochromic ink t ₃ Color-development starting temperature of heat-erasing color-coloring ink and color memory retention-type thermochromic ink t ₄ Heating Complete decolorization temperature (high temperature side discoloration point) of decolorization type thermochromic ink and color memory retention type thermochromic ink

Claims (12)

  A friction body that discolors an image formed using a reversible thermochromic ink from a first state to a second state by frictional heat, wherein the friction body is a styrene-butylene-styrene copolymer or a styrene-ethylene A friction body comprising a butylene-styrene copolymer.   The friction body according to claim 1, wherein the friction body has a Shore hardness A of 55 degrees or more in JIS K6253A. The friction body according to claim 1, wherein the friction body contains a colorant.   4. The friction body according to claim 3, wherein the colorant is contained in an amount of 0.1 to 1.0% by weight in the total amount of the friction body.   5. A writing instrument incorporating a reversible thermochromic ink, wherein at least one friction body according to any one of claims 1 to 4 is used to discolor a handwriting formed by the writing instrument from a first state to a second state by frictional heat. Writing instrument characterized by being provided in the department.   6. The writing instrument according to claim 5, wherein the friction body and the writing instrument body or the writing instrument member are integrally formed by two-color molding.   6. The writing instrument according to claim 5, wherein the friction body is fitted to the writing instrument.   6. The writing instrument according to claim 5, wherein the friction body is a writing instrument member.   A writing instrument comprising: a writing instrument including at least a reversible thermochromic ink; and a friction body according to any one of claims 1 to 4, wherein the writing formed by the writing instrument is discolored from a first state to a second state by frictional heat. set.   The friction material according to any one of claims 1 to 9, wherein the reversible thermochromic ink contains a microcapsule pigment having a high temperature side color change point in a range of at least 25 ° C to 95 ° C. Writing instrument, writing instrument set.   The reversible thermochromic ink is a heat decoloring type that decolors by heating from a colored state, a color memory retaining type that reversibly memorizes a colored state or a decolored state in a specific temperature range, or from a decolored state 11. The heating coloring type that develops color by heating and returns to a decolored state by cooling from the colored state, or any combination thereof. The friction body described above, a writing instrument including the friction body, and a writing instrument set.   The friction body according to any one of claims 1 to 11, wherein the color of the reversible thermochromic ink is colored in one of the first state and the second state, and the other is colorless. Writing instrument, writing instrument set with it.

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