JPH10181272A - Core material for writing utensil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the elastic recovery property of a core tip by a method wherein this core material is constituted in a manner that the mixing ratio of a heat-fusion bonding composite fiber and a polyester fiber of specified melting points respectively, may become a specified range, and at least one part of a mutual contact point of the heat-fusion bonding composite fiber and/or the polyester fiber, is welded or bonded. SOLUTION: For a heat-fusion bonding composite fiber, one component is a polyester-polyalkyleneoxide glycol based block copolymer elastomer, the melting point of which is 100-220 deg.C, and the other part is polyalkyleneterephthalate, the melting point of which is 230-280 deg.C, and they are composed to form the heat-sealable composite fiber. Also, for the polyester fiber, a fiber wherein a terephthalic acid is made its major acidic component, and at least one kind of glycol is polymerized, and the melting point is in a range of 230-280 deg.C, is used. Then, the mixing ratio of the heat-sealable composite fiber and the polyester fiber is made a range of (10:90)-(50:50).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a writing instrument. More specifically, the present invention relates to a core material for a writing instrument having a tip core which is excellent in elastic recovery property, is hard to be crushed, and has excellent writing taste for a long period of time.

[0002]

2. Description of the Related Art As a method of manufacturing a core material for a writing instrument, a short fiber sliver such as polyester, polyacrylonitrile, or polypropylene is impregnated with a thermosetting resin such as melamine, epoxy, or phenol, compressed, heated and impregnated. A method of obtaining a fiber aggregate by curing a thermosetting resin (Japanese Patent Publication No. 44-30649), or a method of converting a fiber aggregate containing a heat-fusible conjugate fiber into a low-melting polymer of the heat-fusible fiber. There is a fiber assembly (Japanese Patent Publication No. 54-688) in which a low-melting polymer is fused by heating as described above.

[0003] However, these core materials are inferior in durability of compression recovery, and the tip portion is deformed with the lapse of use,
In particular, in the case of an ultrafine type pen, the drawbacks of the line width changing with time and becoming thicker, and poor contact with the paper surface and blurring could not be eliminated. Furthermore, in the core material made of the fiber aggregate by impregnation of the thermosetting resin, the unreacted material of the thermosetting resin monomer is concentrated on the front end portion due to a change with time during use, so that the ink is easily blurred due to clogging. . In addition, the conventional cores and cores containing heat-fusible fibers have insufficient rigidity durability, are easily deformed compared to thermosetting ones, and have poor elastic recovery. there were.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems. The present invention has an elastic recovery property at the leading end, hardly causes crushing, changes in line width with time,
An object of the present invention is to provide a core material for a writing instrument with little ink fading.

[0005]

The present invention has the following structure to solve the above-mentioned problems. That is, in the present invention, one component comprises a polyester-polyalkylene oxide glycol-based block copolymer elastomer having a melting point of 100 to 220 ° C, and the other component has a melting point of 230 to 280.
A heat-fusible conjugate fiber composed of a polyalkylene terephthalate having a melting point of 230 to 280 ° C. and a polyester fiber having a melting point of 230 to 280 ° C. so that the mixing ratio is in the range of 10:90 to 50:50. And / or at least a part of the mutual contact points of the polyester fibers is fused or bonded.

Hereinafter, the present invention will be described in detail. The core material for a writing instrument of the present invention is composed of a heat-fusible conjugate fiber and a polyester fiber, and the heat-fusible conjugate fiber and / or at least a part of the mutual contact points of the polyester fibers are fused or bonded. It is configured by bonding. Here, the mutual contact point is
The points of contact between the heat-fusible conjugate fibers by fibers, the points of contact between the heat-fusible conjugate fibers and the polyester fibers, and the points of contact between the polyester fibers by the fibers. At least some of these contact points are fused or adhered.

[0007] The heat-fusible conjugate fiber used in the present invention is a polyester-polyalkylene oxide glycol-based block copolymer elastomer having a melting point of 100 to 220 ° C, and another portion having a melting point of 230 to 280 ° C. Polyalkylene terephthalate is formed by compounding.

[0008] The polyester-polyalkylene oxide glycol-based block copolymer elastomer includes, as a hard segment component, terephthalic acid,
Aromatic dicarboxylic acids such as isophthalic acid, phthalic acid, naphthalene-2,6-dicarboxylic acid, diphenyl 4,4′-dicarboxylic acid, diphenoxyethane dicarboxylic acid, and sodium 3-sulfoisophthalate; 1,4-cyclohexane Alicyclic dicarboxylic acids such as dicarboxylic acids, succinic acid, oxalic acid, adipic acid, sebacic acid, dodecandioic acid, aliphatic dicarboxylic acids such as dimer acid, or at least dicarboxylic acids selected from ester-forming derivatives thereof and the like One kind and an aliphatic diol such as 1,4-butanediol, ethylene glycol, trimethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, neopentyl glycol, decamethylene glycol, or 1,1-cyclohexanedimethanol Alicyclic diols such as 1,4-cyclohexanedimethanol and tricyclodecanedimethanol, or at least one diol component selected from ester-forming derivatives thereof, and polyethylene having an average molecular weight of about 300 to 5,000 Glycol,
Poly (alkylene oxide) glycols such as poly (1,2-propylene oxide) glycol, poly (1,3-propylene oxide) glycol, a copolymer of ethylene oxide and propylene oxide, and a copolymer of ethylene oxide and tetrahydrofuran; It is a terpolymer composed of at least one of them.

However, from the viewpoints of physical properties such as adhesiveness to polyester-based composite components, heat resistance, and strength, a block copolymer polyether polyester having polybutylene-based terephthalate as a hard segment and polyoxytetramethylene glycol as a soft segment has been proposed. preferable. In this case, the polyester portion constituting the hard segment contains 40 to 100 mol% of terephthalic acid and 0 to 50 mol of isophthalic acid as a copolymerization ratio to the total acid component (expressed in mol% based on the total acid component). % Is used.

The acid components other than terephthalic acid and isophthalic acid include phthalic acid, adipic acid, sebacic acid, azelaic acid, dodecane diacid, 2,6-naphthalenedicarboxylic acid, 5-sodium sulfoisophthalic acid, 1,4
When cyclohexanedicarboxylic acid or the like obtains a predetermined melting point, it is preferably used from the viewpoint of elasticity and durability. In particular, those containing 50 to 90 mol% of terephthalic acid and 10 to 35 mol% of isophthalic acid are more preferably used.

The polyetherester block copolymer used in the present invention contains 1,4-butanediol as a main glycol component. The term “main” used herein means that 80 mol% or more of all glycol components is 1,4.
-Butanediol, which means that other glycol components may be copolymerized within a range of 20 mol% or less. Preferred copolymer glycol components used are ethylene glycol, trimethylene glycol,
1,5 pentanediol, 1,6 hexanediol, diethylene glycol, 1,4 cyclohexanediol,
1,4-cyclohexanedimethanol and the like.

Further, the polyetherester block copolymer used in the present invention has an average molecular weight of 300 to 50.
00 poly (alkylene oxide) glycol component to 5
８０80% by weight. Average molecular weight of 800-4
It is particularly preferred that the content of the glycol component is from 30 to 70% by weight at 000. When the average molecular weight is less than 300, the blockability of the obtained block copolymer decreases, and the elastic recovery performance becomes insufficient.

On the other hand, if the average molecular weight exceeds 5,000, the copolymerizability of the poly (alkylene oxide) glycol component decreases, and the elastic recovery performance becomes insufficient, which is not preferable.

When the content of the poly (alkylene oxide) glycol component is less than 5% by weight, even if the conjugate fiber is subjected to a heat bonding treatment, the conjugate fiber having the desired elastic properties can be obtained. On the other hand, if it exceeds 80% by weight, the mechanical properties of the block copolymer and the durability such as heat resistance and light resistance are undesirably reduced.

The melting point of the copolymer elastomer which is a heat-fusible component must be in the range of 100 to 220 ° C. When the melting point is lower than 100 ° C., the polymer becomes brittle and the elastic recovery performance becomes insufficient, which is not preferable. On the other hand, if the melting point exceeds 220 ° C., it is necessary to increase the heat treatment temperature, which is not preferable because the fluidity of the polymer decreases and the adhesive strength decreases. A more preferred range of the melting point is
120-200 ° C.

Polyalkylene terephthalate, which is another component of the heat-fusible conjugate fiber, is polyethylene terephthalate, polybutylene terephthalate, polyhexamethylene terephthalate, poly-1,4-dimethylcyclohexane terephthalate, polyethylene (2,6-naphthalate). , Polypivalolactone, or a polymer comprising these copolymer esters, having a melting point in the range of 230 to 280 ° C. If the melting point is lower than 220 ° C., the proportion of the copolymer component becomes large and the polymer becomes soft, which is not preferable. In particular, polyethylene terephthalate having high compression hardness, and polybutylene terephthalate which does not cause repetitive distortion are preferable.

The weight ratio of the polyester-polyalkylene oxide glycol block copolymer elastomer component to the polyalkylene terephthalate component is 70:30.
It is preferably in the range of 30:70, more preferably in the range of 60:40 to 40:60.

The form of the heat-fusible conjugate fiber may be a core-sheath type,
Or, it may be a side-by-side type, and in the core-sheath type, the core and the sheath may be arranged concentrically,
It may be arranged eccentrically.

The single fiber denier of the heat-fusible fiber is 1 to 3
It is preferably in the range of 0 denier. If the single fiber denier is less than 1 denier, the rigidity is insufficient, and the shape retention as an aggregate is poor, which is not preferable. On the other hand, when the single fiber denier exceeds 30 denier, the rigidity becomes too large, and it is difficult to form uniform inter-fiber voids, and there is a disadvantage that the ink retention is reduced. A particularly preferred range is 2 to 10 denier.

The polyester fiber used in the present invention is a fiber which is a main component of the core material for a writing instrument of the present invention (hereinafter referred to as a main fiber), and terephthalic acid is used as a main acid component;
At least one glycol, preferably selected from ethylene glycol and trimethylene glycol, has been polymerized as the main glycol component. Further, those obtained by copolymerizing the third component may be used as long as the performance is not impaired. The melting point of the polyester fiber is
It is used in the range of 230-280 ° C.

As the polyester fibers, those having a single fiber denier in the range of 1 to 30 denier are preferably used. If the single fiber denier is less than 1 denier, the rigidity is insufficient, and the shape retention as an aggregate is poor, which is not preferable. On the other hand, if the single fiber denier exceeds 30 denier, the rigidity becomes too large, and it is difficult to form uniform inter-fiber voids, and there is a disadvantage that the ink retention is reduced. A particularly preferred range is 2 to 10 denier.

Next, the mixing ratio of the heat-fusible conjugate fiber and the polyester fiber which is the main fiber is from 10:90 to 5: 5.
It must be in the range of 0:50, the optimum value of which can be determined by the choice of each material and its denier. If the mixing ratio of the heat-fusible conjugate fiber is less than 10%, the elastic recovery rate and compression hardness of the fiber molded product are insufficient as a core material for a writing instrument, which is not desirable. Further, when the heat-fusible conjugate fiber is used in an amount exceeding 50%, the crimp degree is low and the shape stability of the fiber molded body is poor, and further, the inter-fiber voids of the fiber molded body are reduced. However, it is not preferable because the liquid retaining property is lowered. Particularly, the preferable range of the cotton mixing ratio is such that the heat-fusible conjugate fiber and the polyester fiber which is the main fiber are 20: 8.
0 to 40:60.

Further, the heat-fusible conjugate fiber and / or
By providing a hydrophilic processing agent to the polyester fiber which is the main fiber, it is possible to supply a core material suitable for a writing implement of aqueous ink.

Examples of hydrophilic processing agents include polyester polyether block copolymers, copolymers of starch derivatives and polyamides, acrylamide derivatives of polyalkylene glycols, and polymers such as polyethylene glycol diamines and polyamide block copolymers. Further, anionic, cationic, nonionic and amphoteric surfactants can be mentioned. In the present invention, among the hydrophilic processing agents, those having a polyester polyether block copolymer as a main component are selected. It is preferable to use it. The reason for this is that the polyester polyether block copolymer has good compatibility with the polyester-based polymer, so that it does not cause adhesion failure with the polyester-based main fiber, and is unlikely to cause a shift in the adhesion point due to heat shrinkage during heat treatment. Therefore, the fibrous structure made of the polyester-based binder fiber to which the polyester polyether block copolymer has been applied has a higher hardness than the non-applied polyester binder fiber, and further has an improved inter-fiber porosity, There is an advantage that the water-based ink is improved, and there is a great advantage in addition to the hydrophilicity that is effective for the aqueous ink. Furthermore, because of good compatibility with the polyester, durable hydrophilicity can be imparted to further improve the liquid retention of the aqueous ink, thereby enabling uniform ink supply. In addition, the applied amount of the hydrophilic processing agent may be in the range of 0.02 to 5% by weight from the viewpoints of hydrophilic effect and economic efficiency.

As a method of manufacturing the core material, a raw material (raw cotton) obtained by mixing the heat-fusible conjugate fiber and the polyester fiber at a predetermined ratio is solidified by a hot air drier, and is then shaped into a core or a core. There is a method of cutting out and using, and a method of putting the mixed raw cotton into a mold or the like and cutting out the hot-pressed one into a shape of a leading or middle core, and using the same. In the present invention, the leading core is a core protruding from a main body of a felt-tip pen or the like, and writing is performed using this tip. The ink is supplied to the core by impregnating the liquid.

[0026]

The writing instrument using the core material of the present invention has little change due to crushing of the leading core, has a long ink life, is less likely to cause ink blurring, and has excellent writing taste. The core material makes it possible to provide a tip core and a core for these writing instruments.

In particular, in the present invention, since the polyester-polyalkylene oxide glycol block copolymer elastomer is used as one component of the heat-fusible conjugate fiber, the fiber contact points described above are elastic, Even with the applied load, there is little deformation due to residual strain and durable compression recovery is obtained, so the tip of the tip does not deform over time, and the line width changes with time even with ultra-fine type pens It is less likely to become fat.

[0028]

The present invention will be described below by way of examples. The manufacturing method and evaluation method of the core material used in this example will be described below.

{Method of Manufacturing Core Material} The heat-fusible conjugate fiber and the polyester fiber which is the main fiber are mixed at a predetermined ratio,
After passing through a carding process to form a laminated web having a thickness of 110 mm, the web was pressed to a thickness of 3.5 mm and heat-treated at a predetermined temperature for 5 minutes to obtain a core substrate as a fibrous structure. Cut out the base material into a strip having a width of 10 mm and a length of 35 mm,
A test core material was created by immersing the aqueous ink in this,
Evaluate by writing test.

{Evaluation Method} A test pen having a test core attached is linearly reciprocated at intervals of 1 m on synthetic paper, and a distance corresponding to the following is measured. 1) Writable distance: writing distance until ink completely disappears (m) 2) Ink blurring distance: writing distance until ink blurring is first confirmed (m) 3) Pen tip crushing distance: wire diameter Is 120% (10mm →
Writing distance (m) up to 12mm)

{Number of Crimps and Degree of Crimp} The number of crimps and the degree of crimp are as described in JIS L1015-7-12-1 and JIS.
It measured based on the method of L1015-7-12-2. {Denier} Measured according to the method of JIS L1015-7-51A. << Average fiber length (cut length) >> Measured according to JIS L1015A method (staple diagram method).

{Porosity} From a core material prepared to a predetermined thickness: a (cm), width: b = 1 cm, length: L = 3.5 c
The sample of m is cut out, the weight of the sample: X (g) is measured, and the porosity: P (%) is calculated by the following equation. P (%) = {(X ₀ −X) / X ₀ ｝ * 100, where X ₀ = ρ * V X ₀ : Volume converted weight of sample ρ: Density converted to constituent fiber (calculated from the following formula) ρ = ρ ₁ * C / 100 + ρ ₂ * (100−C) / 100 ρ ₁ : true density of the heat-fusible conjugate fiber at room temperature (1.0 g
/ Cm ³ ) ρ ₂ : true density of polyester fiber at normal temperature (1.4 g)
/ Cm ³ ) C: mixing ratio (%) of the heat-fusible conjugate fiber V: core material volume (cm ³ ) V = a * b * L

{Compressive elastic strain} Predetermined thickness: a (mm)
Width: b = 2 mm, length: L = 1
A test piece of 0 mm was cut out and the dimensions (a, b,
After correctly measuring L), the test piece was sandwiched in the direction of width b by a parallel compression plate composed of two aluminum plates, and the width was 50%.
(2mm → 1mm), compress and fix until temperature is 70
After heating continuously for 22 hours in a constant temperature bath at ℃, the test piece is taken out, removed from the compression plate, and left at room temperature for 30 minutes. Thereafter, the dimensions of the length of the surface of the test piece that has been in contact with the parallel compression plates (L direction): L ₁ was measured, compressive residual strain: calculated C (percent) from the following equation. _{C = {(L-L 1} ) / L} * 100

[Examples 1 and 2] As the heat-fusible conjugate fiber, the sheath was a polyetherester block copolymer (melting point = 150 ° C.), and the core was polybutylene terephthalate (melting point = 255 ° C.). , Single fiber denier is 3 denier, fiber length is 51 mm, sheath / core weight ratio = 50% / 5
0%, crimp degree is 13.0 peaks / 25 mm, crimp degree is 3.0
%, A polyethylene glycol-polyethylene terephthalate copolymer (PEG-PET: used as a hydrophilic processing agent, the same applies hereinafter) as an oil agent, 0.15% by weight percentage
30% by weight of the added short fiber, polyethylene terephthalate as a main component, polyester fiber as a main fiber, single fiber denier 3 denier, fiber length 51m
m, number of crimps: 11.5 peaks / 25 mm, degree of crimp: 16.0
%, And 70% by weight of short fibers to which 0.15% by weight of stearyl phosphate potassium salt as an oil agent has been applied to form a laminated web having a thickness of 110 mm and a thickness of 3.5 mm. And heat-treated at 180 ° C. to obtain a core substrate having a porosity of 50% (Example 1).

Further, the above-mentioned laminated web having a thickness of 110 mm was pressed to a thickness of 5.8 mm at 180 ° C.
To obtain a core substrate having a porosity of 70% (Example 2).

By using the elastomeric heat-fusible conjugate fiber, a writable distance of a conventional level of 500 to 600 m and a writable distance of 800 to 1000 m can be realized. There was almost no deformation of the core, and an ideal core material was obtained. When the porosity is increased from 50 to 70%, the ink retention amount can be increased without losing the elastic recovery performance, so that the ink life (related to the writable distance) is improved.

Example 3 In the same system as in Example 1, a heat-fusible conjugate fiber and a polyester fiber as a main fiber, both of which had a single fiber denier of 6 denier, were used.
The number of crimps of the heat-fusible conjugate fiber is 11.0 peaks / 25 mm,
It is a short fiber having a degree of crimp of 2.5%, and is a short fiber mainly composed of polyethylene terephthalate as a polyester fiber. The number of crimps is 11.0 peaks / 25 mm and the degree of crimp is 1
Using a material having a thickness of 4.0%, a laminated web having a thickness of 110 mm was pressed so as to have a thickness of 5.8 mm.
Heat treatment was performed at 80 ° C. to obtain a core substrate having a porosity of 50% (the other conditions not described are the same as in Examples 1 and 2). Although the elastic recovery performance is in the direction of improvement by denier up, since the liquid retention volume of the void unit increases,
The ejection of the ink was larger than that in the case where the single fiber denier was 3 deniers, and the writable distance and the blurring of the ink were slightly inferior to those in Examples 1 and 2, but at a good level.

Example 4 Using the same raw cotton as in Examples 1 and 2, 40% by weight of the heat-fusible conjugate fiber and 60% by weight of the polyester fiber as the main fiber were mixed, and the cotton was mixed. Press to 3.5 mm thickness by the same process as
Heat treatment was performed at 0 ° C. to obtain a core substrate having a porosity of 50%. Evaluation was performed in the same manner as in Example 1, and good results were obtained.

Example 5 In the same system as in Examples 1 and 2,
The sheath / core weight ratio of the heat-fused conjugate fiber is 60: 40%,
Single fiber denier is 3 denier, fiber length is 51 mm, number of crimps is 12.5 crests / 25 mm, degree of crimp is 2.0%, and short fibers to which 0.15% by weight of PEG-PET is added as an oil agent are 30. By weight, 70% by weight of the same polyester fiber (main fiber) as in Examples 1 and 2 was mixed to obtain a core material base material having a porosity of 50%. The evaluation result was good.

[Comparative Example 1] The same raw cotton as in Examples 1 and 2 was used, and the blending ratio of the heat-fusible conjugate fiber deviated from the range of claim 1 to a smaller value. Example 1
In the same manner as in 2, a core material base material was obtained. Since the amount of the elastomer heat-adhering fiber was small, the elastic recovery and hardness of the core material were both weak, and the ink life, blurring, and crushing of the core were also deteriorated.

[Comparative Example 2] This is the result of changing to the same system as in Examples 1 and 2, in which the blending ratio of the heat-fused fiber and the polyester fiber as the main fiber is large. The core material tends to be stiffer due to the large number of heat-bonded fibers, but the ink life and blurring performance deteriorated due to the decrease in the inter-fiber void volume due to heat shrinkage.

[Comparative Example 3] As a heat-fusible conjugate fiber, terephthalic acid / isophthalic acid having a sheath having a softening point of 70 ° C was used.
Short fibers made of ethylene glycol / diethylene glycol copolymerized polyester and having a core of polybutylene terephthalate having a melting point of 255 ° C., a single fiber denier of 3 denier, a fiber length of 51 mm, and a sheath / core weight ratio of 50% / 50. %, The number of crimps is 9.5 / 25 mm, the degree of crimp is 14.0%, and 0.10% by weight of stearyl phosphate potassium salt as an oil agent is added: 3
0% by weight and a single fiber mainly composed of polyethylene terephthalate as a main fiber, and a single fiber denier of 3%
Denier, fiber length 51mm, number of crimps 11.5 peaks / 2
5 mm, a crimp degree of 16.0%, a steal phosphate potassium salt as an oil agent added with 0.15% by weight percentage: 70% by weight, and a thickness of 110 mm
After making into a laminated web of, press to 3.5mm thickness,
A core substrate having a porosity of 50% was obtained.

Good results were not obtained with respect to ink life, blurring, and crushing of the core. Table 1 also shows the results of Examples 1 to 5 and Comparative Examples 1 to 3. As shown in Table 1, Examples 1 to
5, the compressive elastic strain was small, and in Comparative Examples 1 to 3, the compressive elastic strain was large, and the effect of the present invention can be understood from the results of the writing test.

[0044]

[Table 1]

* 1: Writing distance (m) until ink no longer comes out with test pen * 2: Writing distance (m) until ink fading is first confirmed with test pen * 3: Line with test pen Writing distance (m) until the diameter becomes 120% Abbreviation: EL: Polyester elastomer PET: Polyethylene terephthalate PBT: Polybutylene terephthalate cPET: Low melting point copolymerized polyester (softening point: 70)
℃) PEG-PET: oil agent based on polyether polyester block copolymer SPK: potassium stearyl (C = 18) phosphate

Claims (4)

[Claims] 1. One component comprises a polyester-polyalkylene oxide glycol-based block copolymer elastomer having a melting point of 100 to 220 ° C., and the other component has a melting point of 230 to 220 ° C.
A heat-fusible conjugate fiber made of polyalkylene terephthalate at 280 ° C. and a polyester fiber having a melting point of 230 to 280 ° C. are configured so that the mixing ratio is in the range of 10:90 to 50:50. A core material for a writing instrument, wherein at least a part of the conjugate fibers and / or the mutual contact points of the polyester fibers is fused or adhered. 2. The weight ratio of the polyester-polyalkylene oxide glycol-based block copolymer elastomer component, which is one component of the heat-fusible conjugate fiber, to the polyalkylene terephthalate component, which is another component, is 70: 30-3.
The core material for a writing instrument according to claim 1, wherein the ratio is 0:70. 3. A hydrophilic processing agent comprising a polyetherester block copolymer as a main component is applied to the surface of one of the heat-fusible conjugate fiber and the polyester fiber, or one of the two. Core material for writing instruments. 4. The heat-fusible conjugate fiber and the polyester fiber have a single fiber denier of 1 to 30 denier.
3. The core material for a writing instrument according to any one of 3.