JPH05238187A - Collector for writing utensil - Google Patents

Abstract

PURPOSE:To provide a collector for a writing utensil more safely subjected to surface treatment and capable of obtaining a pen having an excellent ink tank generating no blowing off or dripping ink by a temp. change. CONSTITUTION:Low temp. plasma treatment of gas having no plasma polymerization properties is applied to a collector for a writing utensil molded from a synthetic resin under pressure of 10<-3>-10Torr.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a writing instrument collector. More specifically, it relates to modifying the wettability of the collector surface.

[0002]

2. Description of the Related Art A writing instrument collector (hereinafter sometimes abbreviated as "collector") is used for a writing instrument that directly stores ink in an ink tank without being absorbed by a batting or the like, and is incorporated in the ink tank. Ink retainer. This collector has a function of temporarily holding the ink pushed out from the ink tank when the air in the ink tank expands due to a temperature rise or the like so as not to drop from the pen tip or the air hole.
Specifically, from the rear end of the ink retainer to the front portion, one or more grooves are formed in the approximately central portion of the ink retainer to the extent that a capillary force works, and the ink at the rear of the retainer is moved forward in the groove. It has a function of guiding to the pen tip. A writing instrument having a structure in which ink is directly stored in an ink tank using a collector can write with a substantially constant ink outflow from the first stroke to the final stroke. In addition, the ink consumption rate is higher than that of batting type writing instruments, that is, ink does not remain in the ink tank after the writing instrument is used up and the stored ink can be used net, and a transparent resin molded product is used for the ink tank. Therefore, there is an advantage that the remaining amount of ink can be visually confirmed easily. For this reason, a collector is indispensable in a writing instrument having an ink tank.

If the wettability of the ink on the surface of the collector is insufficient, the ink ejected from the ink tank may not smoothly enter the retaining groove of the collector, and the capillary force of the retaining groove does not work for the ink that has entered. The ink holding force is weak, and the ink pops out from the holding groove due to impact, and the ink also blows out from the air groove.

As the collector, molded products of various synthetic resins are generally used because of their excellent mechanical strength and moldability.

Conventionally, as a method of modifying the wettability of the surface of a collector made of a synthetic resin molded article, a chemical method of forming a hydrophilic group on the surface by immersing the collector in a strong acid or a strong alkaline solution for several minutes has been used. As the strong acid, for example, a mixed solution of chromic acid, and as the alkali, a sodium hydroxide solution was used.
However, the chemical modification method using these treatment liquids has a high operational risk, and if the collector is not sufficiently cleaned after the treatment, the remaining treatment liquid reacts with the ink to cause a problem in writing instruments. May cause fatal defects in performance.
Moreover, not only is it time-consuming and costly, but also the sustainability of the wettability of the collector deteriorates over time, which is not sufficient as a modification treatment.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to improve the ink wettability of a writing instrument collector made of synthetic resin, and to provide a writing instrument collector which is safe to work and has excellent ink wettability. It is to be.

[0007]

Means for Solving the Problems As a result of repeated studies on the above problems, the inventors of the present invention have performed a plasma treatment on a collector made of a synthetic resin under specific conditions, and then a surface treatment with a vinyl monomer. The inventors have found that the object of the present invention is achieved, and have completed the writing instrument collector of the present invention. That is,

The writing instrument collector of the present invention has a writing instrument collector formed of a synthetic resin, and has a concentration of 10 ^-3 to 1 ^-1.
It is characterized in that, at a pressure of 0 torr, a low temperature plasma treatment of a gas having no plasma polymerizability is performed, and then a surface treatment is performed with a vinyl monomer. Further, preferably, the surface treatment is a graft polymerization of a vinyl monomer onto the collector, and a vinyl monomer having a hydrophilic group is more preferable.

The plasma generation in the low temperature plasma treatment of the writing instrument collector of the present invention is performed, for example, between the electrodes at 20 times.
It suffices to apply electric power of 0 to 3000 MHz and 0.1 to 2 kW, and sufficient results can be obtained with either polar discharge or non-polar discharge. The plasma treatment time varies depending on the applied voltage, but is generally several seconds to several tens of minutes. As a method other than the above method, for example, low frequency, microwave, direct current or the like can be used as the discharge frequency band. The plasma generation mode can be selected from glow discharge, corona discharge, fireworks discharge, silent discharge and the like. Further, the electrodes may be internal electrodes, coil-type equal capacitance coupling, or inductive coupling in addition to the external electrodes. However, no matter what method is used, it is necessary to prevent the surface of the material from being deteriorated by the heat of discharge. Plasma treatment temperature is 0-
It is a low temperature of 50 ° C.

As the gas having no plasma polymerizing property,
Helium, neon, argon, nitrogen, nitrous oxide, nitrogen dioxide, oxygen, air, carbon monoxide, carbon dioxide, hydrogen,
Examples of chlorine include halides such as hydrogen chloride, bromine cyanide and tin bromide, sulfides such as sulfur, sulfurous acid gas and hydrogen sulfide, and these gases may be used alone or in combination.

The gas pressure of these gases in the plasma generator is 10 ^-3 to 10 Torr, preferably 0.
The target plasma can be satisfactorily generated by setting the amount to 01 to 1 Torr.

The writing instrument collector of the present invention is usually
It is molded by injection molding of synthetic resin. Usually, the molding conditions are a nozzle temperature of 260 ° C. and a pressure of 60 to 80 kg / cm ² . Therefore, a synthetic resin suitable for injection molding is preferable. Specifically, polystyrene, polyethylene, polypropylene, nylon, polymethylmethacrylate, polycarbonate, styrene-acrylonitrile copolymer, methylmethacrylate, styrene copolymer, and the like. If necessary, plasticizer,
Stabilizers, antioxidants, processing aids, pigments, inorganic substances and the like can be included.

The vinyl monomer in the surface treatment of the writing instrument collector of the present invention is preferably a vinyl monomer having a hydrophilic group such as acrylamide or styrenesulfonic acid. As the treatment method, the collector is placed in the vapor phase of vinyl monomer, or the collector is treated in an aqueous solution of vinyl monomer or in a liquid phase in an organic solvent. The concentration in the gas phase is 0.
01 to 10% by weight, and the concentration in the liquid phase is preferably 0.1 to 40% by weight. It is believed that this treatment results in the formation of graft-polymerized moieties on the collector surface.

In the treatment performed on the collector of the present invention, polar groups are generated on the surface of the hydrophobic polymer by the plasma treatment to obtain the ink wettability, but most synthetic resins do not have the lasting property. The reason is that a resin having an extremely hydrophobic surface, such as a resin, is more stable when the generated polar group moves to the inside than it is exposed to the outside due to the difference in thermodynamic energy. Is thought to be sunk into the material. However, by the surface treatment with the water-soluble monomer of the present invention, the polar group generated by the plasma treatment is graft-polymerized, the size of the polar group becomes large, and the polar group does not get inside the material, so that the ink wettability is maintained. It is thought that it will be.

[0015]

The present invention will be described in more detail by way of examples. Examples 1 and 2 A collector for a writing instrument molded with high-density polyethylene [Yukaron Hard JX-20 manufactured by Mitsubishi Petrochemical Co., Ltd.] was set in a low-temperature plasma treatment apparatus, and the pressure was reduced to 0.4 Torr ( The pressure was adjusted and maintained at 0.5 torr while passing argon gas at a temperature of 25 ° C., and an oscillating output of 1 kW was applied to the magnetron to generate plasma for 30 seconds. The collector was taken out into the air, put in a 10% aqueous solution of acrylamide, deaerated, and then immersed at 50 ° C. for a predetermined time (Table 1) to perform surface treatment. After taking it out, it was ultrasonically washed with water to obtain a writing instrument collector of the present invention. The above treated collector is assembled in the pen shown below, and the ink shown below is filled up to half the volume of the ink tank. With the cap removed, the temperature is raised from the atmosphere of 25 ° C to 50 ° C. It was investigated whether the ink removed by the expansion of the air in the ink tank does not drop from the pen tip and smoothly enters and is retained in the groove of the collector. 30 tests were conducted, and the number in which ink was blown from the collector and ink dripping from the pen tip was confirmed was counted as defective. Further, in order to compare the durability of the modification treatment of the collector, an experiment was conducted by storing the collector treated by each method and condition at room temperature for one year. The results are shown in Table 1.

Pen used in the experiment: A water-based ball-point pen having a pen tip for a water-based ball-point pen in which a 0.5 mm diameter cemented carbide ball is held by a stainless holder and having an ink tank with a capacity of 2 ml. -Composition of ink used in the experiment: water 80.0 parts blue acid dye 19.9 parts nonionic surfactant 0.1 part-physical properties of ink (25 ° C) viscosity 2.1 cps surface tension 40.2 dyn /
cm pH 7.1

Comparative Example 1 10% acrylamide of Example 1 was not immersed in an aqueous solution. Other than that, it went in the same way. The results are shown in Table 1.

Comparative Example 2 The collector of Example 1 was subjected to a treatment of impregnating a chromic acid mixed solution for 10 minutes, followed by thorough washing with water and drying, without plasma treatment or immersion treatment with an aqueous 10% acrylamide solution. Others did the same. The results are shown in Table 1.

[0019]

[Table 1]

From Table 1, there is a clear difference in the number of defects between the case where the surface is modified and the case where the surface is not modified. Further, it can be seen that the surface modification is excellent in sustainability by further performing the surface treatment in addition to the plasma treatment.

[0021]

The present invention provides a writing instrument collector having excellent ink wettability. By using the collector of the present invention, it is possible to provide a pen in which ink is not ejected and dripping does not occur when the temperature changes. In addition, the treatment method applied to the collector of the present invention is safer than before and is practical in less time.

Claims (2)

[Claims] 1. A writing instrument collector formed of a synthetic resin is subjected to a low-temperature plasma treatment of a non-plasma-polymerizable gas under a pressure of 10 ⁻³ to 10 Torr,
A writing instrument collector consisting of surface treatment with vinyl monomer. 2. The writing instrument collector according to claim 1, wherein the surface treatment with the vinyl monomer comprises grafting the writing collector with the vinyl monomer.