JPH0780388B2 - Pen body for brush pen - Google Patents

Description

TECHNICAL FIELD The present invention relates to a pen body for a brush pen.

(Prior Art) Pen bodies for brush pens include soft pen bodies produced by no-melt extrusion molding and hard pen bodies produced by melt extrusion.
The typical types of them are as follows.

a. A flexible pen body composed of a bundle of many monofilaments of synthetic fibers.

b. A soft pen having a structure in which a large number of filaments of synthetic fiber are bonded in a bundle with a binder.

c. A soft pen having a porous structure.

d. A rigid pen body in which ink capillary passages are formed in the axial direction by melt extrusion molding of a thermoplastic elastomer such as polyurethane.

e. A rigid pen body in which the pen body in the above d is twisted.

f. A rigid pen body having a structure in which an ink capillary passage is formed in the axial direction by melt extrusion molding of a thermoplastic resin such as polyacetal, polyamide or polyester elastomer.
(See JP-A-56-82294 and JP-A-55-139293) (Problems to be solved by the invention) However, each type has the following problems.

Type a: Synthetic fiber core is scattered, ink flow and followability are poor, and strength is weak and there is no stiffness.

b type Synthetic fiber cores are likely to disperse and wear, and it is difficult to reduce the diameter due to insufficient strength.

c type It is difficult to adjust the porosity and the gap between the capillaries, and abnormal noise (rubbing noise) occurs during writing. If the diameter is reduced to around 2 mmΦ, the strength will be insufficient and the porosity will be increased. If it is lowered, the ink flow will be reduced and it cannot be put to practical use.

d type Because it is a hard type for general writing, the writing line width does not change greatly regardless of the strength of the writing pressure, and it has high mechanical strength and is useful for general writing. The line width according to the strength and strength of the pen, various properties as a brush pen such as a stop, a brush, and a brush are not desirable.

In addition to the problems of type e d, the control of the capillary spacing in the ink capillary passage is more unstable.

Although the physical properties of the f-type material have shape retention properties in the melt extrusion molding process, there is no softness and restoring force in terms of hardness.

As described above, there is a problem as a writing pen in both the non-melt extrusion molding process and the melt extrusion molding process.

However, the melt extrusion molding process (Japanese Patent Publication No. Sho 49-2132 and Japanese Patent Publication No. Sho 56-17240) does not have the problem that the molded products are dissimilar, unlike the types a and b. Moreover, the molding process is simple, and it is possible to mold thin diameters of around 1 to 2 mmΦ. In fact, in the general writing nib department of marking pens and felt-tip pens, which require high bending strength and buckling strength, the hardness is By melt extrusion molding of 80 or more such as polyacetal etc., the ink capillary passage shape in the axial direction is as intended design shape, excellent in ink flow and drain back resistance, yet hard without elasticity and high bending strength A pen body with buckling strength and a hard brush feeling is formed.

The present invention has been made in view of such circumstances, and the ink capillary passage in the axial direction has a cross-sectional shape similar to that of the molding die, and while being excellent in both ink flow and drain back resistance, We provide a pen tip that has the elasticity required for brush pen, that is, the softness, the restoring force, and the soft feeling of the pen, and the tip is always sharp without the brush tip coming loose. The purpose is to do.

(Means for Solving Problems) As a result of intensive research to achieve the above-mentioned object, the present inventor has adopted a method of melt extrusion molding and devised a cross-sectional shape and a brush tip shape, and The inventors have found that by finding the synthetic resin to be extrusion-molded and the melt index and hardness of the resin, it is possible to satisfy proper ink drawability without excess and deficiency and various performances as a pen.

Specifically, it is a pen body for a brush pen formed by melt extrusion molding of a synthetic resin material, the cross-sectional shape of which has an ink capillary passage formed by ribs in the axial direction, and at least the axial center portion. The rib is formed by the rib, and the rib on the axial center forms the brush tip, and the synthetic resin is a polyester elastomer and has a melt index (melting index) of 0.5 to 5.0 g / 10 min and a hardness (Shore D) of 30.
It is characterized in that it is configured to be ~ 60.

As the polyester elastomer in the present invention, for example, a melt index 1.8 g / 10 min, which will be described later,
It has a hardness of 46 and is generally composed of a hard segment with a high mechanical strength in the crystalline phase and a soft segment with an amorphous phase and a low glass transition point. It has elasticity and is suitable for obtaining softness and resilience as a pen tip for a brush pen.

The melt index of the high hardness elastomer has a large proportion of hard segments, and the melt viscosity is high even during molding, so that it is necessary to increase the numerical value. Further, since the low hardness elastomer has a large proportion of soft segments, it has a low melt viscosity and needs to have a small numerical value. The hardness is 30 to 60 and 0.5 to 5.0 g / 10 min, which will be described later.

When the melt index exceeds the upper limit, since the melt viscosity is low, the shape retention after extruding from the die in the cross-sectional shape of the ink capillary passage is poor, and an ink capillary passage having a predetermined ink drawability cannot be obtained. On the other hand, if the lower limit is not reached, the melt viscosity will be too high, and it will not be possible to stretch after drawing from the die and molding will not be possible.

The hardness of the polyester elastomer has a cross-sectional shape having an ink capillary passage in the axial direction.The softness of the pen tip varies depending on the user's preference, the cross-sectional shape of the ink capillary passage, etc., but the numerical value is If it is less than 30, it is too soft to obtain a nib as a brush pen. Also, if the value exceeds 60, it is too hard to expect a change in the writing line width due to the strength of the writing pressure.

(Examples and Functions) Hereinafter, the present invention will be described in detail.

1 to 7 illustrate each embodiment of the pen body of the present invention. Each pen body 1 has a melt index of 0.5 to 5.0 g /
In 10 minutes, a polyester elastomer having a hardness of 30 to 60 is melt-extruded to have an ink capillary passage 2 formed by a rib in the axial direction, and at least an axial center portion is formed by the rib. so,
The rib on this axis forms the tip of the brush. Basically, it is extruded by a molding device exemplified in JP-B-56-17240 to form a writing brush shape.

Specifically, in the pen body 1 having the cross-sectional configuration illustrated in FIGS. 1 to 3, a molding opening having a shape similar to the cross-sectional shape of the pen body 1 to be formed, and each portion of the opening are formed. On the other hand, after the synthetic resin is melt-extruded into an enlarged cross-sectional shape of the pen body 1 from a die having a melt flow rate adjusting passage for inducing and controlling an optimum amount of the molten resin, and subsequently dropped to the required pen body 1 diameter. The pen body 1 is formed by cutting it to a required length and grinding the tip into a sharp shape.

In the pen body 1 having the cross-sectional structure illustrated in FIG. 4, a molding opening having a shape similar to the cross-sectional shape of the internal supply element 3 and an optimum amount of molten resin are induction-controlled for each part of the opening. A synthetic resin is melt-extruded into an enlarged cross-sectional shape of the internal supply element 3 from a die having a melt flow rate adjusting passage formed therein.
Subsequently, the inner feed element 3 is drawn down to a desired inner feed element diameter and passed through a coating molding die to form the outer coating 4 on the inner feed element 3 by melt coating, and then cut to a required length and the tip is sharply ground. The pen body 1 is molded.

The cross-sectional configuration illustrated in FIGS. 5 and 6, i.e., an assembly of ink supply elements 5 each forming an ink capillary passage and integrally connecting the ink capillary passages to one another. In the pen-like body 1, a molding opening having a shape similar to the cross-sectional shape of the internal supply element 3 and a melt flow rate adjusting passage for guiding and controlling an optimum amount of molten resin are formed for each part of the opening. The synthetic resin is melt-extruded from the formed die into the enlarged cross-sectional shape of the internal supply element 3, and subsequently, the internal supply element 3 is melt-coated with the jacket 4 by being drawn down to a required internal supply element diameter and passing through a coating molding die. After the formation, the pen body 1 is formed by cutting it into a required length and grinding the tip into a sharp shape.

In the cross-sectional configuration illustrated in FIG. 7, that is, in the pen body 1 in the form of a bundle of ink supply elements 6 each forming an ink capillary passage and communicating the ink capillary passages with each other, A synthetic resin is expanded in the ink supply element 6 from a die having a molding opening having a shape similar to the cross-sectional shape and a melt flow rate adjusting passage for guiding and controlling an optimum amount of molten resin for each part of the opening. After melt-extruding into a cross-sectional shape and then dropping it to the required ink supply element diameter, the required number of the ink supply elements 6 are converged and passed through a coating molding die to form the outer coating 4 by melt coating, and then the required length. Then, the pen body 1 is molded by cutting the tip into a sharp shape.

Further, the cross-sectional shape of the pen body 1 is not limited to the illustrated configuration, and for example, the surface of the rib 7 may be a straight shape having no unevenness as shown in the drawings, or as illustrated in FIGS. 1 to 4. The number of ribs 7 in the pen body 1 may be increased or decreased to increase or decrease the ink capillary passage 2. For example, the pen body 1 of FIG.
In the case of the pen body 1 shown in FIG. 4, the number of ribs 7 is increased to increase the groove length. The independent groove-shaped ink capillary passage 2 having three types of long, medium and short may be configured to have four or five groove lengths.

Further, the inner supply element 3 and the outer cover 4 in the pen body 1 illustrated in FIGS. 4 and 5 may be extruded from a die into the same body. There is also a cross-sectional configuration of the pen body 1 excluding the outer cover 4 and the like.

The following table shows the characteristics of the pen body 1 of the present invention in comparison with the comparative example.

Melt extrusion load: 2160g (): Melt temperature * Restoration rate is fixed after fixing a pen with a diameter of 2 mm and a length of 100 mm (L1) as a test piece in a ring shape for 5 hours. After 30 seconds had elapsed after the release, the length (L2) between both ends of the arc-shaped test product was divided by the above L1 and multiplied by 100.

For comparison, Invention I and Comparative Examples III, IV, V and VI used the same die.

From this table, the pen body 1 of the present invention has a desired cross-sectional shape as designed, and the shape retention, ink flow,
It can be seen that it is excellent in drain back resistance, has no brush tip scatter, and has good restoring force, softness, and writing feel, and has sufficient performance as a pen body for a writing pen.

On the other hand, although the pen A of Comparative Example III gave good results in terms of softness and restoring force, it had a melt index of 9.4 g / 10 min, which was too low in viscosity and lacked in shape retention. As shown in the figure, the cross-sectional shape was not the same as the designed shape, and the desired ink flow and drain back resistance could not be obtained, which made practical use impossible.

The pen B of Comparative Example IV was almost inferior to the inventions I and II in shape retention, but it was also excellent in ink flow and drain back resistance. However, the hardness was 62. It is inferior in softness and resilience and is not suitable as a pen for brush pen.

The pen C of Comparative Example V and the pen D of Comparative Example VI have hardness
By being 80 or more, it lacks resilience and softness,
It has a hard pen feeling and is equivalent to a felt-tip pen.
It is not suitable as a pen for a brush pen.

(Effects of the Invention) Therefore, the present invention has the following advantages.

Good shape retention, exhibiting the cross-sectional shape as designed,
It exhibits the desired ink flow and drain back resistance, has softness and resilience, and has a soft writing feel, and is useful by satisfying various conditions of a pen for a writing pen.

The pen body itself is elastically deformed and restored according to the writing pressure, so that the writing pressure always changes, which is suitable for writing Japanese, especially kanji, and the width of the writing changes according to the strength of the writing pressure.
Suitable as a pen for brush pen.

The cross-sectional shape has an ink capillary passage formed by a rib in the axial direction, and at least the axial center portion is formed by the rib, and the rib on the axial center forms the writing tip, so that the writing tip is It doesn't come loose,
Anyone can always write with a sharp tip.

[Brief description of drawings]

1 to 7 are cross-sectional views illustrating each embodiment of the pen body of the present invention. 8 to 11 are transverse cross-sectional views showing comparative examples which were tested for comparison with the pen body of the present invention. In the figure, 1 is a pen body 2 is an ink capillary passage 7 is a rib

Claims (1)

[Claims] 1. A pen body for a brush pen, which is made of a synthetic resin and is formed by melt extrusion molding, the cross-sectional shape of which is:
It has an ink capillary passage formed by a rib in the axial direction, and at least the axial center portion is formed by the rib, and the rib on the axial center forms a writing tip, and the synthetic resin is melted by a polyester elastomer. A pen body for a brush pen having an index (melting index) of 0.5 to 5.0 g / 10 min and a hardness (Shore D) of 30 to 60.