JPS6161822A - Molding die of synthetic resin nib - Google Patents

Abstract

PURPOSE:To enable to mold a nib, the ink-wetting surface of which is smooth and the cross-section of which gradually decreases diametrically in such a manner that the cross-section at respective position is similar in form with the shaping opening part and the change of the magnitudes of the cross-section at respective position is large, by a method wherein a proper number of melt speed control holes are arranged on the underside of the shaping opening part. CONSTITUTION:A shaping opening part C, the peripheral side walls of which are smooth and which consists of a nearly pipe-like outer contour shaping opening C2, a plurality of partition wall shaping openings C1, which independently extend from the inner side of said opening C2 in the direction of a central air hole, a plurality of branch wall shaping openings C3, which extend from each partition wall shaping opening C1 in the peripheral direction, is recessedly formed in front of a die A, in which the air hole A3 is open. A proper number of melt speed control holes, which are controlled so as to make the passing speeds of melts through the respective part of the shaping opening part at nearly constant, are arranged on the underside of the shaping opening part. Accordingly, the respective melts consisting of the respective parts in the diametrically gradually decreasing cross-section of a nib are controlled to the constant speed by means of the melt speed control holes so as to be shaped into a diametrically gradually decreasing form, the change of the magnitude of the cross-section at respective position of which is large and the ink-wetting surface of which is smooth and the ink passage of which has the predetermined porosity, in order to be extruded from the shaping opening part in the form of a nib, the cross-section of which is similar in form with the shaping opening part.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a molding die for a synthetic resin nib to be included in writing implements such as markers and felt-tip pens, and the present invention relates to a molding die for forming a synthetic resin nib for writing instruments such as markers and felt-tip pens. It is related to the molding die used to mold the pen nib.

(Prior Art) FIG. 9 shows a forming die in the manufacturing method proposed in Japanese Patent Publication No. 53-27973.

This molding die 50 has a large number of discharge holes 51 arranged close to each other, and when the molten synthetic resin is extruded and discharged in the form of a filament from each of these independent discharge holes, the expansion of the synthetic resin, that is, the ballast effect, causes , the extruded synthetic resins are partially welded together outside the die, and the ink passages are left in the non-welded areas, which is the so-called self-adhesive molding method outside the die.

Although it is possible to form the nib to a certain extent, that is, only in the shape of a circular aggregate, with this forming die 50, there are the following drawbacks.

(2) Regarding the degree of machining of the die, the multiple discharge holes provided in the die must be closely spaced from each other. The reason for this is that the envelope of the filament-shaped molten synthetic resin extruded from these discharge holes has a similar shape to the fine voids. For this reason, the difficulty level of Goose's 11th work is extremely high, and it is disadvantageous in terms of price.

■In order to deal with the large degree of irregularity of the die strength, swell ratio and surface roughness (hereinafter referred to as melt fracture phenomenon), the length of the discharge holes must be shortened and the distance between each discharge hole must be narrowed. Therefore, the withstand pressure against the molten resin decreases, and the life of the die is shortened.

(2) Regarding swell ratio In the case of independent discharge holes, in order to make the swell ratio, which is an important factor in molding, appropriate, the hole length must be constant and a constant extrusion pressure is required. In other words, increasing the extrusion rate will cause the melt fracture phenomenon, so an optimum extrusion rate is required, and it is difficult to achieve the optimum swell ratio by simply changing the hole length, so it is difficult to control the swell ratio. The disadvantage is that the area is very narrow and stable molding is difficult.

■Null 1-Fracti 1? - Next to the phenomenon, as the extrusion speed increases, the rate of viscous deformation of the filament discharged from the discharge hole, which is an independent hole, decreases, and the rate of elastic deformation increases, and finally the elastic body breaks. Break similar to *1
In other words, surface cracking occurs, and this phenomenon occurs at extremely high extrusion pressures or extremely high drawing speeds, which disadvantageously affects the capillary flow direction of the ink.

■About the enlargement rate In the self-adhering method outside the die, the assimilation rate of each filament decreases because the circumferential surface of each filament discharged from the discharge hole is exposed to air and cooled at the same time as it is discharged. It gets faster.

Therefore, the enlargement ratio is small, and there is a limit to the ability to form smaller diameter pen nibs. On the other hand, if attempts are made to reduce the diameter, cracks will inevitably occur in various parts of the pen tip cross section, making it impossible to obtain a product.

Furthermore, since the enlargement ratio is small, if the diameter of the pen tip cannot be reduced, the diameter of the die must also be reduced, which has the disadvantage of making the processing even more difficult.

■Since the degree of crystallinity is self-reflecting outside the die, each filament comes into contact with air at the same time as it exits the discharge hole and its peripheral surface is cooled, resulting in a fast cooling rate. )
There is a big disadvantage.

■About weld lines Even when each discharge hole is processed and set in an appropriate R positional relationship, weld lines, which are the joints of each filament, occur at the fused parts of each filament attached to the outside of the die, and the fusion of the filaments occurs. It has the disadvantage of having weak adhesion strength and being a factor in the occurrence of cracks.

■With regard to the degree of freedom of the molding material, the melting index is small and the melting index is low.
Materials that are rough are not suitable, and have the disadvantage of limiting the materials that can be molded.

■ Regarding cooling, each filament is individually cooled by air outside the die, and all the filaments that form the cross section of the pen tip are not relatively cooled, so there is a disadvantage that the internal ink passage gap cannot be controlled. .

(Problems to be Solved by the Invention) The present invention solves the above-mentioned problems (1) to (2) all at once, and also changes the melt passing speed at various parts of the diameter cross section of the pen tip, that is, the melt passing speed at various parts of the mouth of the shaper. An object of the present invention is to make it possible to form a pen nib with a diametrical cross-sectional shape that is similar to the shaped opening, has a large degree of irregularity, and has a smooth ink-wetted surface by controlling the adjustment hole.

(Means for Solving the Problems) In order to achieve the above-mentioned problems, the present invention has a generally pipe-shaped outer contoured l1f1 opening at the front part of the die in which the air hole is opened.
11 portions of the shaped space with a smooth circumferential wall surface consisting of a plurality of partition wall shaping openings extending from the inside of the opening toward the central air hole and branch wall shaping openings extending in the circumferential direction from the partition shaping openings; The present invention is characterized in that a suitable number of melt speed adjusting holes are arranged on the bottom surface of the shaping opening and are controlled so that the melt passing speed at each part of the shaping opening is adjusted to be approximately the same.

(Function) Each melt constituting each part of the diametrical cross section of the pen tip is controlled to the same speed by the melt speed adjustment hole, and the -r of a predetermined porosity with large irregular abrasion and a smooth ink wetted surface is maintained at the same speed by the melt speed adjustment hole.
The pen is shaped into a diametrical cross-sectional form having an ink passage, and after being shaped in this way, it is extruded from the shaped opening to form a similar-shaped pen nib.

(Example) An example of implementation of the present invention will be described in detail below based on the drawings.

The die A has a built-in screw (not shown), and transfers synthetic resin in the form of powder or particles falling from a popper (not shown) from the melt pool B1 to the flow Φ control section B. During this transfer, the die Δ is heated from the outside with a heater (not shown) and the synthetic resin is melted while being transferred.

In addition, the die 8 is provided with an air blowing pipe A1 and an air feeding path A2 that communicates with this blowing pipe. Then, the air hole △3 is opened on the injection surface. The purpose of the air blowing pipe A1 and the air supply path △2 is to supply air and blow out air from the air hole A3 during the stretching process during pen nib manufacture, thereby preventing the synthetic resin from concentrating on the center. A pen nib E without a core is formed.

A shaping opening C having a similar shape to the diameter cross section of the pen tip having the desired diameter cross section to be molded is connected to the front part of the die, that is, the injection surface, through the rear null reservoir B1 and the flow section B. Form. This shaped opening C is the air hole A3
A roughly pipe-shaped outer contour shaping opening C2 concentric with the wall shaping opening C2, and a plurality of partition wall shaping openings C1 extending mutually independently from the inside thereof in the direction of the central air hole A3, etc. and a retaining wall shaping opening C3 extending in the circumferential direction from the right, and the circumferential wall surface of the shaping opening C formed by the circumferential wall surfaces of these openings C2, C+J3, and C3 is shaped into a smooth shape to prevent ink from getting wet. A pen nib E with a smooth surface is formed.

The partition wall shaping opening C1, which extends in communication from an appropriate location inside the roughly pipe-shaped outer shaping opening C2, is shown on three sides (
(Fig. 1) or extending equiangularly from the hexagonal directions (Fig. 3) toward the central air hole A3, with a gap inside the outer wall E+.
Mold E2.

The retaining wall shaping opening C3 communicates with the partition wall shaping opening C1, extends in the circumferential direction, and has inner wall shaping openings C1, intermediate branch wall shaping openings C2, and outer branch wall shaping openings C1, which are arranged in parallel at equal intervals in the radial direction. It consists of an opening c3, and each of these openings C1 and C2
, 03 is all (Fig. 1) or part (
3), and a branch riE3 is formed on the side of the partition wall E2.

The width shape of the partition wall shaping opening CI and the branch road 11 shape C1 is such that in the partition wall shaping opening C1, the width becomes gradually narrower toward the center, and in the retaining wall shaping opening C3, the width is made the same width.
The melt, whose flow rate is controlled by the flow rate control unit B, is fused into the same body and shaped into the same shape within these openings, and then extruded, so that the diameter cross section of the tubular nib body to be stretched is shaped into the opening. It has a shape similar to the C diameter cross section, and has an ink passage having a preferable capillary function in which the ink wetted surface is extended with an equal gap. However, this width relationship is not limited to the relationship shown in the drawings, and the partition wall shaping opening C
It goes without saying that various changes may be made, such as making the widths of 1 the same, or forming the middle part including the retaining wall shaping opening C3 into a narrow or wide shape.

As shown in the drawing, the outflow control part B is a melt speed adjustment hole that is interposed between the shaping opening C and the melt pool B+ to communicate them and to control the melt flow rate. 91; At the shaping interval Ll C2 position, set null 1 to speed adjustment hole B2, and partition wall shaping opening C+11
At the 7th position, the melt speed adjusting hole B3 is shown, and at the branch shaping opening C3 position, the melt speed adjusting hole B4 is shown, but the number and arrangement of the holes are the same as each shaping opening C+.

It is determined in consideration of the radial cross-sectional shape and radial cross-sectional area of C2 and C3, and the melt balance phenomenon.

In addition, the melt speed adjustment holes B2, 83, and 84 have a hole length in each melt speed adjustment hole so that the melt passing speed in the outer contour shaping opening C2, the partition wall shaping opening C1, and the branch wall shaping opening C3 can be controlled at the same speed. and the diameter thereof are set in relation to the diameter cross-sectional area of each shaping opening C+, C2, 03, and in consideration of the laminar flow phenomenon of the melt in the melt pool B1. Specifically, we managed to shorten and expand the hole length and diameter for each part of the orthopedic opening that has a large diameter area, and controlled the length and diameter of each part of the orthopedic opening that has a small diameter cross section. By controlling the elongation and diameter reduction, and controlling the passage speed of the melt at the same speed at each part of the shaping opening C, a Buddha-shaped nib body with a diameter cross-sectional shape similar to that of the shaping opening C is shaped into the shaping opening. It is formed so that it can be extruded from part C.

These melt speed adjustment holes B2, Bs.

Regarding the interrelationship between the control of B4 pore diameter and pore length,
Based on the flow phenomenon that the extrusion amount is approximately proportional to the fourth power of the hole radius and inversely proportional to the hole length, the reason for greatly adjusting the melt flow rate is to intensively manage the hole diameter and improve the melt flow. The fine adjustments are made by intensively controlling the hole length, and controlling both the diameter and length by taking into account the diameter cross-sectional area ratio of each of the shaping openings C+, Cz, and C3.

In this way, the melt speed adjustment hole Bz, 83.

84 is controlled to maintain the melt ratio between the outer contour shaping opening C2, the partition wall shaping opening C+, and the branch wall shaping opening C3, and also to make the melt color ratio within each opening C+, C2, and C3 appropriate to maintain the quality of each part of the cross section. m is made uniform, and the partition wall E2
This is to keep the ink passage E4 constant within a limit where capillary action is likely to occur by determining the cross-sectional shape of the branching E3 to be faithful to the shapes of the partition wall shaping opening C1 and the branch wall shaping opening C3. That is, each melt speed adjustment hole B2, B3
, B4, each of which is extruded at the same speed, expands after exiting the adjustment hole, advances at the same speed as the melt in the adjacent passage, and fuses and integrates into the outer contour shaping opening C2. And shaped with partition wall shaping opening C+ and branch wall shaping opening C3,! 11 The shaped product C is molded and extruded to form a pen nib E having a predetermined porosity.

The pen nib E manufactured using the above-mentioned die has a diametrical cross-sectional shape as shown in FIGS. extend in the centripetal direction at equal angles, and from the left and right sides of all or some of the wA walls E2, the lateral branches E3 extend symmetrically and in the circumferential direction, and are formed by the envelope of these 8 walls. The ink passage E4 is constituted by a circumferential passage E4a and a radial passage E4b communicating with each other at the center.

The advantages of this pen nib E are: ■ While eliminating the second directionality around the axis at the writing angle where the concentric ink passages are formed, it also releases each of these concentric ink passages! ) Single linear ink grooves are connected at the shortest distance to ensure rapid mutual circulation, eliminating the limitations on writing angles that vary during writing, allowing each person to have a variety of writing angles and directions around the axis. By taking into account differences in stroke speed, changes during stroke, and stroke speed, it is possible to obtain handwriting of a constant thickness from beginning to end, from the beginning to the end of the stroke.

■ All the ink passages, partition walls, and branches are arranged symmetrically on the left and right sides of the center line, and the strain during cooling, which is unique to synthetic resin during molding, is balanced on the left and right sides, and the partition walls,
There is no weeping phenomenon, and therefore the ink passage has a suitable porosity similar to that of the mold, ensuring the above-mentioned handwriting. At the same time, the symmetrical partition walls and branches on the left and right sides of each center line are -1 for various writing pressures around the axis! It has a uniform bending stress in the axial direction at various points around the axis, that is, the stiffness, so that a constant internal feel can be obtained on any writing surface around the axis.

(2) Wall surface roughness forming the ink passage does not occur even under extremely high extrusion pressure or extremely high drawing speed and molding speed, and is a smooth wall surface that is not disadvantageous to ink flow.

■ Self-adhesive within the die, cooling rate is slow, crystallinity is high, and thermal strain is small.

- It is integrally molded within the die, and there are no weld lines or cracks that can reduce strength.

■ The ink passage is extruded into a tubular shape and is internally cooled.
It is formed while being cooled and exhibits a desired controlled cross-sectional shape.

The above embodiment is an example of the present invention, and within the scope of the present invention, each partition wall shaping opening C1 may be centered on the opening C1, or each branch wall shaping opening C3 end may be diagonally opposite each other. Facing each other 1. In general, it is not possible to insert each branch wall shaping opening C3 in an intersecting manner leaving a gap for an ink passage, or to arrange the branch wall shaping opening C3 only on one side of the partition wall shaping opening C+. This can be done freely depending on the difference in the diameter cross-sectional shape of the pen tip to be molded.

In addition, the depth of the shaping opening C is controlled in accordance with the diametric cross-sectional shape of the nib E to be shaped, and the width of the branch wall shaping opening C3 in the same opening is widened at its tip. It is desirable to manage the shape including the depth, and the width of the ink passage can also be controlled by this.

In general, it is possible to control the temperature of the die A, for example to a temperature lower than the melt temperature, to promote hardening of the melt and to promote stabilization of the shape of the molten resin within the molding opening C.

Zaranimata, shaping opening C and melt speed adjustment hole B
2, the surface smoothness of B3.84 is increased by plating treatment or chemical corrosion polishing, and the wall surface 1 [(
By reducing the resistance, it is possible to reduce the influence of the laminar flow phenomenon, which is a factor in the degree of deformation.

FIG. 7 shows a molding die related to the present invention, and this die A has a generally pipe-shaped outer contour shaping opening C2 on the front part of the die where the air hole A3 is opened, and a molding die that is independent of each other from the inside of the opening C2. The partition wall shaped opening C+ has three heights, convex, medium and low, extending in the center direction so that the ink passages are shaped as if they flow from each source to the tributaries and then to the main stream. Shaped opening C with a smooth peripheral wall surface
A suitable number of melt speed adjusting holes B2 and B3 are arranged on the bottom surface of the shaping opening C so that the melt passing speed at each part of the shaping opening is almost the same. A pen nib E having a radial cross-sectional shape (not shown) is formed so as to be moldable. The pen nib E formed by this molding die 8 is also smooth in its ink wetting, and the ink passage E4 splits into three directions from the center, further splits into three directions at the tip, and then merges into the center and communicates with each other. ing.

(Effects of the Invention) According to the die of the present invention, it is possible to form a pen nib having a smooth ink-wetted surface and an ink passage communicating with each other in the circumferential direction and the radial direction into a shape substantially similar to the shaping opening. can.

And there are the following advantages.

■ Regarding machining efficiency, the shaping opening has a quadruple shape and its circumferential wall surface is smooth, so there is no need for strict mutual relationships like the discharge holes of the die in the filament method. The allowable range of accuracy is extremely wide, so the difficulty of manufacturing the die is extremely low, and it is also advantageous in terms of price.

■Strength Since the tubular method uses shaping openings and melt speed adjustment holes to manage the flow rate and shaping, the degree of irregularity can be reduced to 13
In order to deal with the melt fracture phenomenon, the length of the independent discharge holes must be shortened and the distance between each discharge hole must be narrowed. The die part reinforces the base part where the melt speed adjustment hole is formed, which has strong pressure resistance against molten resin and has a long die life.

■About swell ratio Since the flow rate and shaping are controlled using a tubular system with shaping openings and melt speed adjustment holes, it is possible to adjust the rate of change in melt extrusion pressure and extrusion amount, expanding the control range of swell ratio. This allows for stable molding over a wide range of molding areas.

■About melt fracture phenomenon Because it is a tubular type, the limit value of the melt shear rate is high, and surface cracks do not occur even at high productivity extrusion speeds, and there is no disadvantage in ink flow, and the productivity is high. It is possible to control the condition of the surface (ink-wetted surface) that colors the capillary phenomenon that is essential for a pen tip.

■About the enlargement rate Since the self-heading method inside the die allows for internal and external cooling using the die J5 and air holes, the enlargement rate is large and it is possible to form a pen tip with a smaller diameter. There is an advantage that the diameter can be increased and the processing of the shaped opening becomes easier.

■ Regarding the degree of crystallinity, the self-adhering method within the die allows an internal cooling method using air holes, so the cooling rate is slow, and the advantage is that the degree of crystallinity is high and thermal strain is small.

■About the weld line Because it is a self-adhesive method in a die that extrudes into a tube shape,
It is strong because it does not have weld lines, which can cause cracks, unlike the outside-die self-destruction method in which filament is extruded, bundled, and formed.

■ Regarding the degree of freedom of molding materials, even materials with low swell ratios and high melting indexes can be made larger than the swell ratio of the resin itself, and can be molded into a diameter cross-sectional shape that is almost the same as the orthopedic opening. .

Therefore, there is an advantage that the molding material is not limited.

■About cooling Since the internal cooling system allows for centralized control of cooling of the walls that form the ink passages, it has the advantage of being able to freely control the gap between the ink passages.

[Co., Ltd.] Regarding melt flow rate adjustment in each section of the cross section, by adjusting the length, diameter, number, and arrangement of each melt speed adjustment hole, you can freely control the melt flow rate from subtle to large adjustments, and the degree of irregularity is large. It is possible to control mold and large amounts of melt to optimally hang the melt in accordance with the area of each portion of the diametrical cross section of the pen nib, which has a variety of different surface shapes.

■ The pen tip has a diametrical cross-sectional shape with a branch wall that has an enlarged ink coating surface and a highly irregular shape.The melt flow velocity at each part of the shaping opening is controlled by the melt speed adjustment hole to make the mass of melt uniform at each part of the cross-section. Thus, it is possible to continuously manufacture the diameter cross-sectional shape that is faithful to the shape of the opening.

[Brief explanation of the drawing]

FIG. 1 is a front view showing one embodiment of the molding die of the present invention. FIG. 2 is a side view of ffl[r along line II-I. FIG. 3 is a front view showing another embodiment. Figure 4 is ■-IVI
Vertical side view along I. Figures 5 and 6 are the first
FIG. 4 is an enlarged sectional view showing a radial cross section of a pen nib formed by the molding die shown in FIGS. FIG. 7 is a front view of a forming die related to the present invention. FIG. 8 is a sectional view showing a radial cross section of a pen point formed by the molding die of FIG. 7. FIG. 9 is a front view showing a conventional filament die. In the figure, A is die A3, air hole B2.133, B4fJ mel 1 to speed adjustment hole C is shaping opening C1 is partition shaping opening C2 is outer shaping opening 03 is branch wall shaping opening Patent Applicant Thibaud Co., Ltd. Figure 5 Figure 6 Hi 4b Figure 7 1:52, Figure 8 Drawing 8 (no change in content) Procedure 7 City official document October 5, 1980 Mr. Manabu Shiga, Commissioner of the Patent Office (Patent Office examination (Government) 1. Indication of the incident 1982 Patent Application No. 183239
No. 2, Name of the invention Molding die for synthetic resin pen nibs Address 5-14-7 Hakusan, Bunkyo-ku, Tokyo Showa
Year, month, day 7, content of amendment
-3゛, two engravings of figures 1 to 6 and figure 9 (
(No changes to the contents) should be submitted as a separate sheet. Procedural amendment October 17, 1981 1, Indication of the case Patent Application No. 183239 of 1983 2, Name of the invention Molding die for synthetic resin nib 3, Person making the amendment Relationship to the case Name of the patent applicant ( Name) Thibaud Co., Ltd. 4, Agent Address: 5-14-7 Hakusan, Bunkyo-ku, Tokyo, Showa Year, Month, Day 6, Drawing subject to amendment: Figure No. e, Figure H 4b

Claims (1)

[Claims] The front part of the die in which the air holes are opened includes a roughly pipe-shaped outer contour shaping opening, a plurality of partition shaping openings extending from the inside of the opening toward the center independently, and branch wall shaping extending from the partition shaping opening in the circumferential direction. A shaping opening is recessed and the circumferential wall surface consisting of the opening is smooth, and a melt speed adjustment hole is provided at the bottom of the shaping opening, which is controlled so that the melt passing speed at each part of the shaping opening is approximately the same. A synthetic resin nib molding die consisting of an appropriate number of dies.