JP7023060B2 - Stationery - Google Patents

Description

The present invention relates to a writing instrument.

It has a cap having a first member formed of a hard resin and a second member formed of a soft resin such as an elastomer formed so as to cover the outer surface of the first member, and has a first member and a first member. A writing tool in which two members are formed by two-color molding is known (see, for example, Patent Document 1).

In the writing tool described in Patent Document 1, the rear end surface (rear end surface 4c) of the first cylindrical member (clip member 2) comes into contact with the contact surface (locking surface 7c) of the writing tool body, and the cap and the writing tool body Fitting is completed.

Japanese Unexamined Patent Publication No. 2014-159173

Here, as a result of the first member being slightly molded and shrunk between the primary molding of the first member and the secondary molding of the second member, a gap is generated between the first member and the mold, and the gap is formed during the secondary molding. A burr may be formed due to the inflow of the resin into the resin. There is also a method of manufacturing a mold in consideration of the amount of molding shrinkage so that burrs are not formed, but it is difficult to completely predict the shrinkage rate.

This will be briefly described with reference to FIG. FIG. 13 is a diagram illustrating a state of molding shrinkage and secondary molding of the cap. In FIG. 13, (A) is a schematic view showing a primary molded product 100 and a core pin 110 in a state where secondary molding is originally desired, and (B) is a primary molded product 100, a core pin 110, and a secondary molding. It is a schematic diagram which shows the product 120. As a result of the gap G being generated by the molding shrinkage, the resin for secondary molding flows into the gap, and the burr 130 is formed.

When a part of the contact surface 140 of the first member, which is the primary molded product 100, is covered with the burr 130, the contact surface of the writing tool body becomes the contact surface when the cap is fitted to the writing tool body. It comes into contact with the burr 130 before 140, resulting in poor fitting. As a result, the airtightness inside the cap is lost, and as a result, the ink volatilizes from the pen tip, making writing impossible, or the cap may fall off from the writing instrument body. There is also a problem that the user cannot obtain a click feeling when the cap is attached to the writing tool body.

An object of the present invention is to prevent the formation of burrs that hinder the fitting of caps.

According to one aspect of the present invention, the writing instrument comprises a first member, a cap having a second member formed so as to cover the outer surface of the first member, and a writing instrument main body, wherein the first member. And the second member are formed by two-color molding, the first member is a primary molded product, the second member is a secondary molded product, and the first member has a first contact surface. The writing instrument main body has a second contact surface, and when the cap and the writing instrument main body are fitted, the first contact surface and the second contact surface come into contact with each other, and the first contact surface Provided is a writing instrument characterized in that a concave portion or a convex portion is formed in the first member at a boundary portion between the first member and the second member in the vicinity.

Further, according to another aspect, the first contact surface may not be covered with the second member.

Further, according to another aspect, the concave portion or the convex portion may be a step or a slope.

Further, according to another aspect, the second member may be formed of a soft resin.

Further, according to another aspect, the writing instrument may be a heat-discolorable writing instrument, and the handwriting of the writing instrument may be easily thermally discolored by the frictional heat generated when the writing instrument is rubbed by the second member.

According to the aspect of the present invention, it has a common effect of preventing the formation of burrs that hinder the fitting of the cap.

It is a vertical sectional view of the writing instrument according to 1st Embodiment of this invention. It is a perspective view of the rolling prevention member. It is a perspective view of a cap body. It is an enlarged vertical sectional view of a cap. It is an enlarged vertical sectional view of the fitting part of a cap and a writing instrument main body. It is a vertical cross-sectional view of the split surface at the time of primary molding of a cap. It is a vertical cross-sectional view of the split surface at the time of secondary molding of a cap. It is a figure explaining the state of molding shrinkage and secondary molding of a cap. It is a figure explaining the state of the molding shrinkage and the secondary molding of the cap of the writing instrument by the 2nd Embodiment. It is an enlarged vertical sectional view of the 1st contact surface of the rolling prevention member of a writing instrument according to 2nd Embodiment. It is an enlarged vertical sectional view of the 1st contact surface of the rolling prevention member of a writing instrument according to 3rd Embodiment. It is an enlarged vertical sectional view of the 1st contact surface of the rolling prevention member of a writing instrument according to 4th Embodiment. It is a figure explaining the state of molding shrinkage and secondary molding of a cap.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Corresponding components are designated with a common reference code throughout the drawings.

FIG. 1 is a vertical sectional view of a writing tool 1 according to the first embodiment of the present invention. The writing instrument 1 has a cap 2, a writing instrument main body 3 into which the cap 2 is fitted, and a refill 5 which is a writing body arranged in the writing instrument main body 3 and having a writing unit 4 at one end. In the present specification, in the axial direction of the writing instrument 1, the writing unit 4 side is defined as the "front" side, and the side opposite to the writing unit 4 is defined as the "rear" side.

The cap 2 has a rolling prevention member 10 which is a first member, and a cap body 20 which is a second member formed so as to cover the outer surface of the rolling prevention member 10. The rolling prevention member 10 and the cap body 20 are formed by two-color molding, the rolling prevention member 10 is a primary molded product formed of a hard resin, and the cap body 20 is formed of a soft resin such as an elastomer. The next molded product. The soft resin described here refers to a viscoelastic material having rubber elasticity, and the surface hardness of the material is 0 to 90 in the durometer A hardness specified in JIS K6203 or less than 40 in the durometer D hardness. Further, the rolling prevention member 10 and the cap body 20 may be formed of the same material.

2 is a perspective view of the rolling prevention member 10, FIG. 3 is a perspective view of the cap body 20, and FIG. 4 is an enlarged vertical sectional view of the front side of the cap 2.

The rolling prevention member 10 is a tubular member, and an end surface 11 having a circular through hole at a substantially center in the radial direction is formed at one end thereof. In the axial direction of the cap 2, the side on which the end face 11 is formed is defined as the "front" side, and the completely open side opposite to the end face 11 is defined as the "rear" side.

A plate-shaped protrusion 12 extending in the axial direction and protruding outward in the radial direction is formed on the outer peripheral surface of the rolling prevention member 10. Three through holes 13 are formed in the plate-shaped protrusions 12 at equal intervals along the axial direction. During the two-color molding, the resin for the secondary molding flows into the through hole 13 to enhance the bond between the rolling prevention member 10 and the cap body 20. Further, other grooves and holes are formed on the outer peripheral surface of the rolling prevention member 10, further enhancing the coupling force between the rolling prevention member 10 and the cap body 20.

A plurality of ribs 14 are formed on the inner peripheral surface in the vicinity of the end surface 11 of the rolling prevention member 10. The plurality of ribs 14 guide and hold the writing tip of the writing instrument main body 3 inserted in the cap 2. Further, a plurality of fitting protrusions 15 are formed on the inner peripheral surface near the opening at the rear end of the rolling prevention member 10. The plurality of fitting protrusions 15 guide and hold the rear portion of the writing tool main body 3 inserted in the cap 2. As will be described later, a first contact surface 16 and a recess 17 recessed forward with respect to the first contact surface 16 are formed in an annular shape on the outer peripheral edge of the rear end surface of the rolling prevention member 10. ..

The cap body 20 is a tubular member, and an end surface 21 provided with a circular through hole is formed at one end thereof. The cap body 20 covers the outer surface of the rolling prevention member 10 and extends further rearward beyond the rear end of the rolling prevention member 10. The outer peripheral surface of the cap body 20 is smoothly formed, and the portion corresponding to the plate-shaped protrusion 12 of the rolling prevention member 10 is gently filled with a secondary molding resin around the plate-shaped protrusion 12. A protruding portion 22 is formed. Since the cap 2 has the protruding portion 22, it is possible to prevent the cap 2 and the writing tool 1 from rolling on a desk or the like. A locking projection 23 is formed on the inner peripheral surface of the cap body 20 over the entire circumference.

FIG. 5 is an enlarged vertical sectional view of a fitting portion between the cap 2 and the writing instrument main body 3, and specifically, is an enlarged view of a portion A in FIG. The rolling prevention member 10 has a first contact surface 16 and a recess 17 recessed toward the front. A fitting protrusion 6 is formed on the outer peripheral surface of the writing tool main body 3 in the vicinity of the fitting portion over the entire circumference. The front portion of the fitting projection 6 is formed in a stepped shape, and the annular second contact surface 7 facing the front is formed in the stepped portion. In FIG. 5, the first contact surface 16 of the rolling prevention member 10 and the second contact surface 7 of the writing instrument main body 3 are brought into contact with each other so as to coincide with each other.

Here, the mating process will be briefly described. When the writing tool main body 3 is inserted into the cap 2, the fitting protrusion 6 of the writing tool main body 3 comes into contact with the locking protrusion 23 of the cap main body 20 and locks. When the writing tool main body 3 is further pushed in from this state, the cap main body 20 is elastically deformed toward the outside in the radial direction, the fitting protrusion 6 of the writing tool main body 3 gets over the locking protrusion 23 of the cap main body 20, and the writing tool main body 3 The second contact surface 7 collides with the first contact surface 16 of the rolling prevention member 10, and the fitting is completed. In the event of this collision, it produces a clicking sound that is pleasing to the user.

FIG. 6 is a vertical cross-sectional view of the split surface of the cap 2 during primary molding. In the primary molding, the rolling prevention member 10 is molded by using the first mold 30. The first mold 30 has a first core pin 31 having a shape complementary to the inner surface of the rolling prevention member 10, a second core pin 32 that abuts the tip of the first core pin 31, and the first core pin 31 and the second core pin 32. It has a first mold portion 33 that surrounds the periphery of the above. Since FIG. 6 is a cross section of the divided surface of the first mold 30, FIG. 6 shows the surface of the first mold portion 33, not the cross section. That is, on the surface shown in FIG. 6, the mold is matched with the other first mold portion 33 having the same shape.

The gap in the state where the first core pin 31, the second core pin 32 and the two first mold portions 33 are molded is formed so as to correspond to the outer shape of the rolling prevention member 10. Therefore, by pouring the molding material (resin) injected from the nozzle (not shown) of the injection molding machine into this gap from the sprue (not shown) through the gate 34 in the first mold portion 33, the rolling prevention member 10 Can be injection molded.

FIG. 7 is a vertical cross-sectional view of the split surface of the cap 2 during secondary molding. In the secondary molding, the cap body 20 is molded by using the second mold 40. The second mold 40 has a third core pin 41 having a shape complementary to the inner surface of the cap body 20, a fourth core pin 42 that abuts the tip of the third core pin 41, and a third core pin 41 and a fourth core pin 42. It has a second mold portion 43 that surrounds the periphery. Since FIG. 7 is a cross section of the divided surface of the second mold 40, in FIG. 7, the surface of the second mold portion 43 is shown instead of the cross section. That is, on the surface shown in FIG. 7, the mold is matched with the other second mold portion 43 having the same shape.

The gap in the state where the third core pin 41, the fourth core pin 42, and the two second mold portions 43 are molded is formed so as to correspond to the outer shape of the cap body 20. Therefore, the cap body 20 is injection-molded by pouring the molding material (resin) injected from the nozzle (not shown) of the injection molding machine into this gap from the sprue (not shown) through the gate 44 of the fourth core pin 42. can do.

FIG. 8 is a diagram illustrating a state of molding shrinkage and secondary molding of the cap 2. 8A and 8B are schematic views showing a rolling prevention member 10 and a third core pin 41 in a state where secondary molding is originally desired, and FIG. 8B is a rolling prevention member 10 and a third core pin 41. It is a schematic diagram which shows the cap body 20 and the cap body 20. Due to the molding shrinkage of the rolling prevention member 10, a gap is formed between the rolling prevention member 10 and the third core pin 41.

In this regard, the third core pin 41 is provided with a protruding seal convex portion 45, which is complementary to the concave portion 17 of the rolling prevention member 10 by design, facing the concave portion 17. The height of the seal protrusion 45, that is, the distance between the first contact surface 16 of the design roll prevention member 10 and the bottom surface 18 of the recess 17, in other words, the design roll prevention member 10 of the third core pin 41. The distance between the surface that abuts on the first contact surface 16 and the surface that abuts on the bottom surface 18 of the recess 17 is designed to be larger than the assumed width of the gap. As a result, a microcavity 46 is formed between the concave portion 17 of the rolling prevention member 10 and the seal convex portion 45 of the third core pin 41. At the time of secondary molding, although the resin flows into the microcavities 46, the inflow of the resin that extends to the first contact surface 16 of the rolling prevention member 10, that is, exceeds the seal convex portion 45 is prevented.

Therefore, according to the present embodiment, the contact between the first contact surface 16 of the rolling prevention member 10 and the second contact surface 7 of the writing instrument main body 3, that is, the fitting between the cap 2 and the writing instrument main body 3 is hindered. This has the effect of preventing the formation of burrs on the first contact surface 16 of the rolling prevention member 10.

Hereinafter, another embodiment having the same effect will be described.

FIG. 9 is a diagram illustrating a state of molding shrinkage and secondary molding of a writing instrument cap according to the second embodiment, and FIG. 10 is a diagram showing a first contact surface 51 of a rolling prevention member 50 of the writing instrument according to the second embodiment. It is an enlarged vertical sectional view of.

In the writing tool according to the first embodiment, the concave portion 17 recessed forward with respect to the first contact surface 16 is formed in an annular shape on the rear end surface of the rolling prevention member 10, whereas the second embodiment is used. The writing tools differ from these embodiments only in that a convex portion 52 projecting rearward with respect to the first contact surface 51 is formed in an annular shape on the rear end surface of the rolling prevention member 50.

9A and 9B are schematic views showing a rolling prevention member 50 and a third core pin 53 in a state where secondary molding is originally desired, and FIG. 9B is a rolling prevention member 50 and a third core pin 53. It is a schematic diagram which shows the cap main body 54. Due to the molding shrinkage of the rolling prevention member 50, a gap is created between the rolling prevention member 50 and the third core pin 53.

In this regard, the third core pin 53 is provided with a protruding seal recess 55, which is complementary to the convex portion 52 of the rolling prevention member 50 by design, facing the convex portion 52. The depth of the seal recess 55, that is, the distance between the first contact surface 51 in the design roll prevention member 50 and the top surface 56 of the convex portion 52, in other words, the design roll prevention member 50 in the third core pin 53. The distance between the surface that abuts on the first abutment surface 51 and the surface that abuts on the top surface 56 of the convex portion 52 is designed to be larger than the expected width of the gap. As a result, a microcavity 57 is formed between the convex portion 52 of the rolling prevention member 50 and the seal concave portion 55 of the third core pin 53. At the time of secondary molding, although the resin flows into the microcavities 57, the inflow of the resin that extends to the first contact surface 51 of the rolling prevention member 50, that is, exceeds the seal recess 55 is prevented.

FIG. 11 is an enlarged vertical cross-sectional view of the first contact surface 61 of the rolling prevention member 60 of the writing instrument according to the third embodiment. The present embodiment is different from the first embodiment only in that a recess 62 recessed forward with respect to the first contact surface 61 is formed in an annular shape on the rear end surface of the rolling prevention member 60. .. The recess 62 is defined by a tapered slope 63 formed on the outer peripheral surface of the rolling prevention member 60.

FIG. 12 is an enlarged vertical cross-sectional view of the first contact surface 71 of the rolling prevention member 70 of the writing instrument according to the fourth embodiment. This embodiment is different from the first embodiment only in that a convex portion 72 projecting rearward with respect to the first contact surface 71 is formed in an annular shape on the rear end surface of the rolling prevention member 70. There is. The convex portion 72 is defined by a slope 73 cut along the outer peripheral edge of the rear end surface of the rolling prevention member 70.

According to the above-described embodiment, a concave portion or a convex portion is formed in the rolling prevention member at the boundary portion between the rolling prevention member and the cap main body in the vicinity of the first contact surface. That is, as long as the first contact surface of the rolling prevention member that comes into contact with the second contact surface of the writing tool main body can be molded so as not to be covered by a part of the writing tool main body, a concave portion or a convex portion having an arbitrary shape is adopted. be able to. The concave portion or the convex portion may be a step as in the first embodiment and the second embodiment, may be a slope as in the third embodiment and the fourth embodiment, or may have another shape. good.

In the above-described embodiment, the fitting portion between the cap 2 and the writing instrument main body 3 in the writing instrument 1 has been described, but another member in which the same fitting is performed in the first member and the second member also has the above configuration. Is applicable.

By the way, the cap body of the cap may be formed of a material that can erase the handwriting of the writing instrument. In this case, the cap body can be used as an erasing member for the handwriting of the writing instrument.

The refill 5 in the above-described embodiment may contain a heat-changing ink containing a heat-changing coloring material. In this case, the writing tool 1 is a heat-discolorable writing tool, and the handwriting of the writing tool 1 can be thermally discolored by the frictional heat generated when the writing tool 1 is rubbed by a friction body as an erasing member.

Here, the heat-discolorable ink is a different color (one color of the second writing tool) when a predetermined color (first color) is maintained at room temperature (for example, 25 ° C.) and the temperature is raised to a predetermined temperature (for example, 60 ° C.). ), And then when cooled to a predetermined temperature (for example, -5 ° C), the ink has the property of returning to the original color (first color). In the writing instrument 1 using the heat-changing ink, the second color is made colorless, and the temperature of the drawn line written in the first color (for example, red) is raised to make it colorless, which is referred to as "erasing" here. .. Therefore, the drawn line is rubbed against the writing surface or the like on which the drawn line is written by a friction body to generate frictional heat, whereby the drawn line is changed to colorless, that is, erased. As a matter of course, the second color may be colored other than colorless.

The thermochromic microcapsule pigment used as a thermochromic coloring material is a pigment that changes color due to heat such as frictional heat, for example, if it has a function of changing from colored to colorless, colored to colored, colorless to colored, and the like. The present invention is not particularly limited, and various substances can be used, and examples thereof include microencapsulated heat-discoloring compositions containing at least a leuco dye, a color-developing agent, and a discoloration temperature-adjusting agent.

The leuco dye that can be used is not particularly limited as long as it is an electron donating dye and functions as a color former. Specifically, conventionally known inks such as triphenylmethane type, spiropyran type, fluorane type, diphenylmethane type, rhodamine lactam type, indrill phthalide type, and leucooramine type are used from the viewpoint of obtaining an ink having excellent color development characteristics. It can be used alone (1 type) or in combination of 2 or more (hereinafter, simply referred to as "at least 1 type").

Specifically, 6- (dimethylamino) -3,3-bis [4- (dimethylamino) phenyl] -1 (3H) -isobenzofuranone, 3,3-bis (p-dimethylaminophenyl) -6. -Dimethylaminophthalide, 3- (4-diethylaminophenyl) -3- (1-ethyl-2-methylindole-3-yl) phthalide, 3- (4-diethylamino-2-ethoxyphenyl) -3- (1) -Ethyl-2-methylindole-3-yl) -4-azaphthalide, 1,3-dimethyl-6-diethylaminofluorane, 2-chloro-3-methyl-6-dimethylaminofluorane, 3-dibutylamino-6 -Methyl-7-anilinofluolane, 3-diethylamino-6-methyl-7-anilinofluolane, 3-diethylamino-6-methyl-7-xylidinofluolane, 2- (2-chloroanilino) -6- Dibutylaminofluorane, 3,6-dimethoxyfluolane, 3,6-di-n-butoxyfluolane, 1,2-benz-6-diethylaminofluorane, 1,2-benz-6-dibutylaminofluorane, 1,2-Benz-6-ethylisoamylaminofluorane, 2-methyl-6- (N-p-tolyl-N-ethylamino) fluorane, 2- (N-phenyl-N-methylamino) -6- (N-p-tolyl-N-ethylamino) fluorane, 2- (3'-trifluoromethylanilino) -6-diethylaminofluorane, 3-chloro-6-cyclohexylaminofluorane, 2-methyl-6- Cyclohexylaminofluorane, 3-di (n-butyl) amino-6-methoxy-7-anilinofluorane, 3,6-bis (diphenylamino) fluorane, methyl-3', 6'-bisdiphenylaminofluorane , Chloro-3', 6'-bisdiphenylaminofluorane, 3-methoxy-4-dodecoxystylinoquinolin, and the like.

These leuco dyes have a lactone skeleton, a pyridine skeleton, a quinazoline skeleton, a bisquinazoline skeleton, and the like, and develop color development when these skeletons (rings) are opened.

The color developer that can be used is a component having an ability to develop the color of the leuco dye, and is, for example, a phenol resin compound, a salicylic acid metal chloride, a salicylic acid resin metal salt compound, a solid acid compound, or the like. Can be mentioned.

Specifically, o-cresol, tertiary butylcatechol, nonylphenol, n-octylphenol, n-dodecylphenol, n-stearylphenol, p-chlorophenol, p-bromophenol, o-phenylphenol, hexafluorobisphenol, p. -Hydroxybenzoate n-butyl, p-hydroxybenzoate n-octyl, resorcin, dodecyl gallate, 2,2-bis (4'-hydroxyphenyl) propane, 4,4-dihydroxydiphenylsulfone, 1,1-bis (4'-Hydroxyphenyl) ethane, 2,2-bis (4'-hydroxy-3-methylphenyl) propane, bis (4-hydroxyphenyl) sulfide, 1-phenyl-1,1-bis (4'-hydroxy) Phenyl) ethane, 1,1-bis (4'-hydroxyphenyl) -3-methylbutane, 1,1-bis (4'-hydroxyphenyl) -2-methylpropane, 1,1-bis (4'-hydroxyphenyl) ) N-hexane, 1,1-bis (4'-hydroxyphenyl) n-heptane, 1,1-bis (4'-hydroxyphenyl) n-octane, 1,1-bis (4'-hydroxyphenyl) n -Nonan, 1,1-bis (4'-hydroxyphenyl) n-decane, 1,1-bis (4'-hydroxyphenyl) n-dodecane, 2,2-bis (4'-hydroxyphenyl) butane, 2 , 2-bis (4'-hydroxyphenyl) ethyl propionate, 2,2-bis (4'-hydroxyphenyl) -4-methylpentane, 2,2-bis (4'-hydroxyphenyl) hexafluoropropane, At least one of 2,2-bis (4'-hydroxyphenyl) n-heptane, 2,2-bis (4'-hydroxyphenyl) n-nonane and the like can be mentioned.

The amount of the developer to be used may be arbitrarily selected according to the desired color density, and is not particularly limited, but is usually 0.1 to 1 part by mass with respect to 1 part by mass of the above-mentioned leuco dye. It is preferable to select within the range of about 100 parts by mass.

The color change temperature adjusting agent that can be used is a substance that controls the color change temperature in the coloration of the leuco dye and the color developer. As the discoloration temperature adjusting agent that can be used, conventionally known ones can be used. Specific examples thereof include alcohols, esters, ketones, ethers, acid amides, azomethins, fatty acids, hydrocarbons and the like.

More specifically, bis (4-hydroxyphenyl) phenylmethane dicaprylate (C ₇ H ₁₅ ), bis (4-hydroxyphenyl) phenylmethane dilaurate (C ₁₁ H ₂₃ ), bis (4-hydroxyphenyl) phenyl. Methanedimilistate (C ₁₃ H ₂₇ ), bis (4-hydroxyphenyl) phenylethane dimiristate (C ₁₃ H ₂₇ ), bis (4-hydroxyphenyl) phenylmethane dipalmitate (C ₁₅ H ₃₀ ), bis At least one such as (4-hydroxyphenyl) phenylmethane dibehenate (C ₂₁ H ₄₃ ), bis (4-hydroxyphenyl) phenylethylhexylidene dimyristate (C ₁₃ H ₂₇ ) and the like can be mentioned.

The amount of the discoloration temperature adjusting agent used may be appropriately selected depending on the desired hysteresis width, the color density at the time of color development, and the like, and is not particularly limited, but is usually, with respect to 1 part by mass of the leuco dye. It is preferably used within the range of about 1 to 100 parts by mass.

The thermochromic microcapsule pigment is obtained by microencapsulating a thermochromic composition containing at least the leuco dye, a color developer, and a color change temperature adjusting agent so that the average particle size is 0.2 to 3 μm. Can be manufactured. Examples of the microencapsulation method include an interfacial polymerization method, an interfacial polycondensation method, an insitu polymerization method, an in-liquid curing coating method, a phase separation method from an aqueous solution, a phase separation method from an organic solvent, a melting dispersion cooling method, and an air vapor. Examples thereof include a suspension coating method and a spray drying method, which can be appropriately selected depending on the intended use.

For example, in the phase separation method from an aqueous solution, a leuco dye, a color developer, and a discoloration temperature adjuster are heated and melted, then put into an emulsifier solution, heated and stirred to disperse them in the form of oil droplets, and then used as a capsule film agent. Using a resin raw material, for example, an amino resin solution, an isocyanate-based resin solution, etc. are gradually added, and the reaction is continued to prepare the mixture, and then the dispersion is filtered to produce the desired thermochromic microcapsule pigment. be able to.

The contents of these leuco dyes, color developeres, and color change temperature adjusters vary depending on the leuco dye, color developer, type of color change temperature adjuster, microencapsulation method, etc. used. The color-developing agent is 0.1 to 100 and the discoloration temperature adjusting agent is 1 to 100 in terms of mass ratio. The mass ratio of the capsule membrane agent to the capsule contents is 0.1 to 1.

The thermochromic microcapsule pigment can be obtained by appropriately combining the types and amounts of the leuco dye, the color developer, and the color change temperature adjusting agent to obtain the color development temperature (for example, color development at 0 ° C. or higher) and the decolorization temperature (for example, 0 ° C. or higher) of each color. For example, (decoloring at 50 ° C. or higher) can be set to a suitable temperature, and it is preferable that the color changes from colored to colorless due to heat such as frictional heat.

In the heat-discolorable microcapsule pigment, the wall film is preferably formed of a urethane resin, a urea / urethane resin, an epoxy resin, or an amino resin from the viewpoint of further improving the drawing density, storage stability, and writability. Examples of the urethane resin include a compound of isocyanate and a polyol. Examples of the epoxy resin include a compound of an epoxy resin and an amine. Examples of the amino resin include melamine resin, urea resin, benzoguanamine resin and the like. The thickness of the wall film of the microcapsule coloring material is appropriately determined according to the required strength of the wall film and the drawing density.

The average particle size of the heat-discolorable microcapsule pigment is colorability, color-developing property, easy-decoloring property, stability, fluidity in ink, and suppresses adverse effects on writability. From the viewpoint of compatibility with the microcapsule pigment, it is preferably 0.2 to 5 μm, more preferably 0.3 to 3 μm. The "average particle size" specified here is a value obtained by measuring the average particle size (50% diameter) (refractive index 1.8) with a particle size analyzer [Microtrack HRA9320-X100 (manufactured by Nikkiso Co., Ltd.)]. Is.

If the average particle size is less than 0.2 μm, sufficient line density cannot be obtained, while if it exceeds 5 μm, the writing property is deteriorated, the dispersion stability of the heat-discolorable microcapsule pigment is lowered, and the ink due to vibration is generated. It is not preferable because backing is likely to occur. Further, the 90% diameter is 8 μm or less, preferably 6 μm or less. When particles having a large diameter are present in a certain proportion or more, the above-mentioned influence tends to become more remarkable. The microcapsule pigment in the above-mentioned average particle size range (0.2 to 5 μm) varies depending on the microencapsulation method, but in the phase separation method from an aqueous solution or the like, stirring is performed when producing the microcapsule pigment. It can be prepared by appropriately combining the conditions.

The specific gravity of the heat-discolorable microcapsule pigment is in the range of 0.9 to 1.3, preferably 1.0 to 1.2. When the specific gravity is out of this range, the dispersion stability of the microcapsule pigment tends to decrease. Further, microcapsule pigments having a specific gravity of more than 1.3 are liable to cause ink back due to vibration.

In the water-based ink composition for writing tools, in addition to the above-mentioned heat-discoloring microcapsule pigment, water (tap water, purified water, distilled water, ion-exchanged water, pure water, etc.) as a solvent as a balance, and for each writing tool (ballpoint pen). Depending on the application (for marking pens, etc.), a water-soluble organic solvent, thickener, lubricant, rust preventive, preservative or antibacterial agent, etc. may be appropriately contained within the range that does not impair the effect. can.

Examples of the water-soluble organic solvent that can be used include glycols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, polyethylene glycol, 3-butylene glycol, thiodiethylene glycol, and glycerin, and ethylene glycol monomethyl ether and diethylene glycol monomethyl. It can be used alone or in admixture with ether.

Of these, glycerin is preferably used for the purpose of suppressing ink solidification in the writing portion due to ink back, and the amount of glycerin added is preferably 1 to 10% by mass with respect to the total amount of ink. The mechanism of action by glycerin is unknown, but it is presumed to have the effect of reducing the cohesive force of pigments and ink components in a dry state.

As the thickener that can be used, for example, at least one selected from the group consisting of synthetic polymers, cellulose and polysaccharides is preferable. Specifically, Arabic gum, tragacant gum, guar gum, locust bean gum, alginic acid, carrageenan, gelatin, xanthan gum, welan gum, succinoglycan, dieutan gum, dextran, methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, starch glycolic acid and The salt, arginate propylene glycol ester, polyvinyl alcohol, polyvinylpyrrolidone, polyvinylmethyl ether, polyacrylic acid and its salts, carboxyvinyl polymer, polyethyresioxide, copolymer of vinyl acetate and polyvinylpyrrolidone, crosslinked acrylic acid polymer and Examples thereof include the salt thereof, a non-crosslinked acrylic acid polymer and a salt thereof, a styrene acrylic acid copolymer and a salt thereof, and the like.

Of these, it is preferable to use polysaccharides. Due to its rheological properties, polysaccharides tend to be less susceptible to the effects of vibration on fluidity, and are less likely to cause problems such as writing defects due to ink back. In particular, xanthan gum is preferable because it has an excellent balance with other characteristics required for writing tool ink.

As the lubricant, fatty acid ester of polyhydric alcohol, which is also used as a surface treatment agent for pigments, higher fatty acid ester of sugar, polyoxyalkylene higher fatty acid ester, alkyl phosphate ester, alkyl sulfonate of higher fatty acid amide, alkyl allyl sulfone. Examples thereof include esters, derivatives of polyalkylene glycols, fluorine-based surfactants, and polyether-modified silicones. Examples of the rust preventive include benzotriazole, tolyltriazole, dicyclohexylammonium nitrate, and saponins. Examples of the preservative or antibacterial agent include phenol, sodium omadin, sodium benzoate, benzimidazole compounds and the like.

In order to produce this water-based ink composition for writing tools, a conventionally known method can be adopted. For example, in addition to the above-mentioned heat-discoloring and photo-discoloring microcapsule pigments, a predetermined amount of each component in the above-mentioned water-based is used. It is obtained by blending and stirring and mixing with a stirrer such as a homomixer or a disper. Further, if necessary, coarse particles in the ink composition may be removed by filtration or centrifugation.

The viscosity value of the water-based ink composition for writing tools is preferably 500 to 2000 mPa · s at a shear rate of 3.83 / s and 20 to 100 mPa · s at a shear rate of 383 / s. By setting the viscosity in the above range, it is possible to obtain an ink having excellent writability and stability over time. Further, S = αD ⁿ (where 1>n> 0) (S is shear stress (dyn / cm ² ), D is shear rate (s ^-1 ), α is non-Newtonian viscosity coefficient). The required non-Newtonian viscosity index n is preferably 0.2 to 0.6. By setting the non-Newtonian viscosity index n in the above range in addition to the above viscosity range, it is possible to appropriately set the fluidity of the ink with respect to vibration, and it is possible to prevent the occurrence of ink back.

The surface tension of the water-based ink composition for writing tools is preferably 25 to 45 mN / m, more preferably 30 to 40 mN / m. Within this range, the balance between the inside of the pen tip and the wettability of the ink becomes appropriate, and it becomes possible to prevent the occurrence of ink back.

In the refill, the ink follower may be placed immediately behind the ink. The material constituting the follower can be at least composed of a non-volatile or refractory organic solvent and a thickener. The non-volatile or refractory organic solvent used for the ink follower is used as the base oil of the ink follower, and for example, liquid paraffin is used. As the liquid paraffin, mineral oil and chemically synthesized oil are used, and as the chemically synthesized oil, polybutene, poly-α-olefin, ethylene α-olefin oligomer and the like can be used.

Specific examples of the mineral oil that can be used include commercially available Diana process oils NS-100, PW-32, PW-90, NR-68, and AH-58 (manufactured by Idemitsu Kosan Co., Ltd.).

Specific examples of the polybutene that can be used include commercially available Nissan polybutene 200N, polybutene 30N, polybutene 10N, polybutene 5N, polybutene 3N, polybutene 015N, polybutene 06N, polybutene 0N (all manufactured by Nippon Oil & Fat Co., Ltd.), and polybutene. Examples include HV-15 (manufactured by Nippon Petrochemical Co., Ltd.) and 35R (manufactured by Idemitsu Kosan Co., Ltd.).

Specific poly-α-olefins that can be used include, for example, commercially available barrel process oils P-26, P-46, P-56, P-150, P-350, P-1500, P-2200, and the like. (P-10000, P-37500) (manufactured by Matsumura Petroleum Co., Ltd.) and the like can be mentioned.

Specific ethylene α-olefin oligomers that can be used include, for example, commercially available Lucant HC-10, HC-20, HC-100, HC-150, (HC-600, HC-2000) (above, Mitsui). (Made by Chemicals), etc.

These non-volatile or non-volatile organic solvents can be used alone or in combination of two or more.

Examples of the thickener used for the ink follower include calcium salt of phosphate ester, fine particle silica, polystyrene-polyethylene / butylene rubber-polystyrene block copolymer, polystyrene-polyethylene / propylene rubber-polystyrene block copolymer, and hydrogenated styrene. -Butadiene rubber, block copolymer of styrene-ethylenebutylene-olefin crystal, block copolymer of olefin crystal-ethylenebutylene-olefin crystal, acetalkoxyaluminum dialchelate and the like can be used, and one or more of these can be used.

Preferred commercially available products of the calcium salt of the phosphoric acid ester that can be used include Crodax DP-301LA (manufactured by Croda Japan Co., Ltd.) and the like. The fine particle silica that can be used includes hydrophilic fine fine silica and hydrophobic fine fine silica, and preferable commercially available products of hydrophilic silica include AEROSIL-300 and AEROSIL-380 (manufactured by Nippon Aerosil Co., Ltd.). Preferred commercially available products of hydrophobic silica include AEROSIL-974D, AEROSIL-972 (manufactured by Nippon Aerosil Co., Ltd.) and the like.

Preferred commercially available polystyrene-polyethylene / butylene rubber-polystyrene block copolymers include Clayton GFG-1901X, Clayton GG-1650 (above, Shell Japan), Septon 8007, Septon 8004 (above, Kuraray) and the like. Can be mentioned. Further, preferred commercially available polystyrene-polyethylene / propylene rubber-polystyrene block copolymers include Clayton GG-1730 (manufactured by Shell Japan), Septon 2006, Septon 2063 (all manufactured by Kuraray) and the like.

Preferred commercially available hydrogenated styrene-butadiene rubbers include DYNARON1320P, DYNARON1321P (above, manufactured by JSR), Toughtech Hl041, Toughtech Hl141 (above, manufactured by Asahi Kasei Kogyo Co., Ltd.) and the like.

Preferred commercial products of the block copolymer of styrene-ethylenebutylene-olefin crystal include DYNARON4600P (manufactured by JSR), and preferred commercial products of the block copolymer of olefin crystal-ethylenebutylene-olefin crystal include DYNARON6200P and DYNARON6201B (manufactured by JSR). JSR Corporation) and the like.

Preferred commercially available products of acetalkoxyaluminum dialchelates include Plenact AL-M (manufactured by Ajinomoto Fine-Techno Co., Ltd.) and the like.

Among these thickeners, it is preferable to use a thermoplastic olefin-based elastomer such as a block copolymer of styrene-ethylenebutylene-olefin crystal and a block copolymer of olefin crystal-ethylenebutylene-olefin crystal.

Further, from the viewpoint of obtaining an ink follower that prevents the occurrence of ink back, the average value of the tan δ values measured for each frequency while increasing exponentially in the frequency domain 1 to 63 rad / s shall be 1.0 or more. Is preferable, and 1.7 to 3.4 is more preferable.

Here, tan δ is a value meaning a loss elastic modulus / storage elastic modulus, and conventionally, it is an average value of tan δ values measured for each frequency while increasing exponentially in the frequency domain “1 to 63 rad / s”. It has been known that a value of 1.0 or less is preferable. In the present invention, by setting the average value of the tan δ values measured for each frequency from 1 to 63 rad / s to 1.0 or more, it is possible to absorb vibration and prevent the occurrence of ink back.

As a material for forming the friction body, a rubber elastic material such as a thermosetting rubber such as silicone rubber, nitrile rubber, ethylene propylene rubber, or ethylene propylene diene rubber, or a thermoplastic elastomer such as a styrene elastomer, an olefin elastomer, or a polyester elastomer, A mixture of two or more kinds of rubber elastic materials and a mixture of rubber elastic materials and synthetic resin can be used, and this is subjected to a wear test (ASTM D1044) specified in JIS K7204 under a load of 9.8 N and a 1000 rpm environment. Below, the amount of taber wear on the wear wheel H-22 of the taber wear tester is configured to be less than 15 mg, and a friction body is formed.

Further, in the case of a friction body, it is preferable that the durometer A hardness specified in JIS K6203 is 70 or more and 90 or less. As a result, a predetermined hardness can be secured, and a more stable scraping operation becomes possible. The friction body can also be applied as a touch pen or a stylus pen, and may be provided with conductivity.

Further, by setting the brightness value of the friction body to 70 or less, the dirt on the surface due to the use of the friction body can be made inconspicuous.

The luminance value is obtained by measuring the surface of the friction body using the HLS color space system using a measuring device such as a general-purpose color difference meter (TC-8600A, manufactured by Tokyo Denshoku Co., Ltd.).

1 Writing tool 2 Cap 3 Writing tool body 4 Writing tool 5 Refill 6 Fitting protrusion 7 Second contact surface 10 Rolling prevention member 16 First contact surface 17 Recess 20 Cap body 23 Locking protrusion

Claims (1)

A writing instrument comprising a first member, a cap having a second member formed so as to cover the outer surface of the first member, and a writing instrument main body.
The first member and the second member are formed by two-color molding, the first member is a primary molded product, and the second member is a secondary molded product.
The first member has a first contact surface, the writing tool main body has a second contact surface, and when the cap and the writing tool main body are fitted, the first contact surface and the second contact surface are used. It comes into contact with the contact surface,
A concave portion or a convex portion is formed at the boundary portion between the first member and the second member in the vicinity of the first contact surface.
The concave portion or the convex portion is formed on the outer peripheral edge of the rear end surface of the first member, the concave portion or the convex portion is covered with the second member, and the first contact surface is covered with the second member. A writing tool that is characterized by not having.

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