JP2001063272A - Ink back-flow inhibitor composition for writing instrument and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink back-flow inhibitor composition having excellent ink back-flow preventiveness, impact resistance and rapid followability without viscosity change, appearance change or the like for a long period and being stable for an ink component of a writing instrument and a method for manufacturing it. SOLUTION: The ink back-flow inhibitor composition for a writing instrument comprises a first volatile retardant liquid of a mixed liquid of one or more types selected from an α-olefin oligomer, ethylene-α-olefin cooligomer and isoparaffin oil, a second volatile retardant liquid and a metal soap. The method for manufacturing the composition is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink backflow preventive composition for a writing instrument and a method for producing the same. More specifically, the present invention relates to an ink backflow preventive composition for writing implements, which is a high-viscosity fluid that advances to the rear end face of ink contained in an ink containing cylinder as ink is consumed, and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, various proposals have been made as ink backflow preventive compositions for writing instruments. For example,
No. 47318 discloses an ink backflow preventive based on liquid polybutene and thickened with fine particle silica or a cellulose-based gelling agent. Also, 1-10
No. 554 discloses an ink backflow preventive in which a non-volatile solvent is thickened with dibenzylidene sorbitol or tribenzylidene sorbitol.

Further, Japanese Utility Model Publication No. 54-15705 discloses a silicone grease combined with a membrane plate.
JP-A-2946 discloses an ink backflow preventive comprising a mixture of petrolatum, liquid paraffin and silicone oil.

[0004]

Among the above-mentioned conventional general-purpose ink backflow preventers, those using polybutene as a base oil include dyes, ionic surfactants, polyvinyl alcohol, etc., which are blended in writing inks. Contact with preservatives such as resin or sodium omadine, phenolic acid, etc., and also with silicone-based antifoaming agents, etc., causes a clouding phenomenon of the ink backflow preventer and a decrease in viscosity due to a decrease in the effect of the thickener. In some cases, ink deterioration was caused.
These phenomena also occur when the polybutene is replaced with a naphthenic hydrocarbon or an organic solvent having a polar group.

[0005] Further, as a thickening agent for gelling a hardly volatile liquid, fine particle silica, dextrin fatty acid ester,
Representative examples include benzylidene sorbitols and acylated amino acid derivatives.However, the ink backflow preventive gelled with the fine particle silica and dextrin fatty acid ester has a large temperature dependency of viscosity, and at high temperatures, the ink decreases due to a decrease in viscosity. The backflow performance is inferior, and at low temperatures, the viscosity rise causes ink follow-up to be hindered. In addition, benzylidene sorbitols and acylated amino acid derivatives may cause problems such as a decrease in viscosity due to shearing, and an increase in viscosity over time to decrease followability.

An object of the present invention is to solve the above-mentioned conventional problems, and an object of the present invention is to provide an ink backflow prevention member which is less deteriorated by components in the ink, and has excellent followability and backflow prevention performance. . In the present invention, “front” refers to the pen tip side, “rear” refers to the ink backflow prevention body side, and “erect” refers to the pen tip facing upward, and “inverted” refers to the pen tip facing downward. To do so.

[0007]

SUMMARY OF THE INVENTION The present invention is directed to an ink backflow preventing member which is disposed on a rear end face of ink directly stored in an ink storing cylinder of a writing implement and advances as ink is consumed.
A first hard-volatile liquid and a second hard-volatile liquid in which the ink backflow preventer is at least one kind or a mixed liquid of two or more kinds selected from an α-olefin oligomer, an ethylene-α-olefin cooligomer and an isoparaffin oil; And metal soap.

[0008] The second hardly volatile liquid is one or a mixture of two or more solvents selected from good solvents for metal soap, and the second hardly volatile liquid is selected from refined mineral oil and polybutene. One or more mixed liquids, the metal soap is aluminum stearate, the metal soap is added in an amount of 1 to 10% by weight, and the first to the second hardly volatile liquid The compounding ratio (weight ratio) of the non-volatile liquid is 1 or more;
25 minutes per minute with a spread meter (parallel plate viscometer)
To 50 mm (measured at 20 ° C.).
A method for producing an ink backflow preventive for writing implements, characterized in that the second non-volatile liquid is thickened in advance with a metal soap and then mixed with the first non-volatile liquid. .

[0009] Compared with the conventional base oil of the ink backflow preventive represented by polybutene, the first hardly volatile liquids used in the present invention are α-olefin oligomer, ethylene-α-olefin cooligomer and isoparaffin. When oil is used as the main component of the ink backflow preventive, the ink has high stability against the above ink components, and the ink backflow preventive or the ink does not deteriorate. However, on the other hand, since the stability is high, Gelling with a thickener is somewhat difficult.

The refined mineral oil, which is the second hardly volatile liquid of the present invention, is relatively stable to the above ink components,
Further, a stable gel can be formed by adding a thickener. However, when an ink backflow preventive is prepared alone, the gel formed is not sufficiently hard regardless of the amount of the thickener added, and the backflow prevention performance is poor. Insufficiency, or a part of the ink backflow preventer may rise in the ink due to standing upright, block the ink flow passage, and cause poor writing or inability to write.

The inventor of the present invention has intensively studied the application of the good stability of the first non-volatile liquid and the gel-forming ability of the second non-volatile liquid to an ink backflow preventer, and completed the present invention. Reached. That is, the first liquid which is one or a mixed liquid of two or more kinds selected from α-olefin oligomers, ethylene-α-olefin cooligomers, and isoparaffin oils
By mixing a metal soap and a second non-volatile liquid, which is one or more mixed liquids selected from good solvents for metal soaps such as refined mineral oil, polybutene, and the like, the stability to ink components and It has been found that an ink backflow preventive having both ink backflow prevention performance and good followability can be obtained.

Furthermore, a more stable ink backflow preventer can be obtained by thickening the second non-volatile liquid with a metal soap such as aluminum stearate in advance, and then mixing the first non-volatile liquid with the first non-volatile liquid. Can be

In order for the ink backflow preventer of the present invention to exhibit good backflow prevention performance, the first non-volatile liquid α
It is preferable that the kinematic viscosity of one or a mixture of two or more kinds selected from olefin oligomers, ethylene-α-olefin cooligomers, and isoparaffin oil is 1000 cSt or more. The second non-volatile liquid is not particularly limited as long as it has a certain level of stability to ink. However, in consideration of properties such as stability, viscosity, and gel forming ability, a high-viscosity lubricating oil is used. Paraffin-based refined mineral oil is preferably used. 40 ° C among the above refined mineral oils
Has a viscosity of 350 cSt or more, and generally referred to as bright stock oil is the most excellent in the backflow prevention performance and the gel stability.

Incidentally, as the second hardly volatile liquid of the present invention,
Conventionally used polybutenes are also exemplified.
As described above, the ink backflow preventive in which polybutene is blended as the main component causes the ink backflow preventive or the ink to deteriorate due to the interaction with the ink component as described above. It has also been found that such inconvenience can be solved by mixing with other non-volatile liquids as one component of the ratio.

Here, the compounding ratio (weight ratio) of the first hard-to-volatile liquid to the second hard-to-volatile liquid is preferably 1 or more. The second refractory liquid has a lower molecular weight than the first refractory liquid and a higher proportion of the second refractory liquid, that is, the proportion (weight ratio) of the two is less than 1. In the case of (1), the low molecular weight components tend to increase and separate over time. Separated low molecular weight components may seep out to the interface between the ink backflow preventer and the ink storage cylinder, deteriorating the ink backflow prevention performance, or rising up in the ink by standing upright and blocking the ink flow path at the rear end of the chip. There is.

Examples of the thickener include dibenzylidene sorbitol, tribenzylidene sorbitol, amino acid derivatives such as acylated amino acids, dextrin fatty acid ester, 12-hydroxystearic acid, hydrophobic fine particle silica, and metal soap. Metal soap is preferably used because of its low temperature dependence of viscosity and good stability over time. Among them, aluminum stearate has high gel transparency, is stable to ink components, does not cause separation or change in viscosity even when left under high temperature conditions for a long period of time, and satisfies the characteristics as an ink backflow prevention body most. Is what you do.

If the amount of the metal soap is less than 1% by weight, the viscosity of the obtained ink backflow preventive body is insufficient, and sufficient ink backflow preventive performance cannot be obtained. Flows out to the rear of the ink container. Further, when the addition amount of the metal soap is 10% by weight or more, the viscosity of the obtained ink backflow preventer becomes excessive,
Insufficient ink supply at the time of writing due to reduced ink follow-up performance causes inconveniences such as breaks in the writing line.
Therefore, the addition amount of the metal soap is preferably 1 to 10% by weight.

As the thickener, the above-mentioned aluminum stearate alone may be used, but other thickeners may be supplementarily added for adjusting the viscosity and preventing separation of the base oil. In addition, polymers such as low molecular weight polypropylene (atactic polypropylene) and ethylene-α-olefin copolymer are added to improve backflow prevention performance, and silicone-based defoamers are added to promote defoaming during production. You can also.

One of the methods for measuring the viscosity (hardness) of the ink backflow preventer is a spread meter (parallel plate viscometer).
There is. When the measured value of the spread meter at 20 ° C. (hereinafter referred to as SM value) is less than 25 mm, the viscosity is too high, so that the ink followability is insufficient and the writing line may be interrupted at the time of writing. On the other hand, if the SM value is 50 mm or more, the ink is prevented from flowing back to the rear of the ink containing cylinder due to insufficient viscosity due to standing upright. The SM value of the ink backflow preventer at 20 ° C. is preferably 25 to 50 mm.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION The ink anti-reflective composition for a writing instrument of the present invention is prepared by thickening a second non-volatile liquid with a metal soap in advance.
It is obtained by mixing with the first non-volatile liquid, and is used by filling the rear end side of the ink stored in the ink storage tube.

[0021]

EXAMPLES Ink backflow preventers of Examples and Comparative Examples having the following compositions were prepared and subjected to performance tests. In the composition, "parts" means "parts by weight". The SM value of each ink backflow preventer at 20 ° C. was also measured. Example 1 Refined mineral oil 40 parts [Mitsubishi Oil Corporation, trade name; diamond SN150 bright stock, viscosity 480 cSt (40 ° C)] Aluminum stearate 6 parts [Nippon Oil & Fats Co., trade name; aluminum stearate # 900] The above components were mixed and heated and stirred at 135 ° C. to dissolve aluminum stearate in a transparent state, and then cooled to room temperature to obtain a second gelling product of a hardly volatile liquid. α-Olefin oligomer 39 parts [Mobil Sekiyu KK, trade name; Mobil SHF-403, viscosity 400 cSt (40 ° C)] Ethylene-α-olefin cooligomer 15 parts [Mitsui Petrochemical Co., Ltd., trade name Lucant HC-600, viscosity 9850c St (40 ° C)] The above components were mixed to obtain a first non-volatile liquid. A uniform ink backflow preventer was prepared by mixing the first hardly volatile liquid and the gelled product of the second hardly volatile liquid with three rolls. The SM value of the ink backflow preventer at 20 ° C. was 43 mm.

Example 2 Refined mineral oil 30 parts [manufactured by Idemitsu Kosan Co., Ltd., trade name; Diana Fresia W-380, viscosity 409c St (40 ° C.)] Aluminum stearate 5 parts [manufactured by NOF CORPORATION, trade name Aluminum stearate # 600] The above components were mixed, heated and stirred at 140 ° C. to dissolve aluminum stearate in a transparent state, and then cooled to room temperature. Obtained. Ethylene-α-olefin cooligomer as the first non-volatile liquid [Mitsui Petrochemical Co., Ltd., trade name; Lucant HC-
150, a viscosity of 2200 cSt (40 ° C.)] and 65 parts of the gelled substance of the second hardly volatile liquid were mixed with a three-roll mill to prepare a uniform ink backflow preventer. The SM value of this ink backflow preventer at 20 ° C. is 3
5 mm.

Example 3 Refined mineral oil 36 parts [manufactured by Idemitsu Kosan Co., Ltd., trade name; Diana Fresia W-380, viscosity 409c St (40 ° C.)] Aluminum stearate 4 parts [manufactured by NOF CORPORATION, trade name Aluminum stearate # 900] The above components were mixed and heated and stirred at 140 ° C. to dissolve aluminum stearate in a transparent state, then cooled to room temperature, and gelled the second hardly volatile liquid. Obtained. Ethylene-α-olefin cooligomer 59 parts [Mitsui Petrochemical Co., Ltd., trade name; Lucant HC-100, viscosity 1300c St (40 ° C)] Fine particle silica 1 part [Nippon Aerosil Industry Co., Ltd. trade name; Aerosil R972] Uniform ink backflow prevention by mixing the above-mentioned first non-volatile liquid ethylene-α-olefin cooligomer, finely divided silica and gelled substance of the second non-volatile liquid with three rolls. Created body. The SM value of this ink backflow preventer at 20 ° C. was 37 mm.

Comparative Example 1 95 parts of polybutene [trade name, manufactured by Nippon Oil Co., Ltd .; polybutene 15H, viscosity 550 cSt (40 ° C.)] 5 parts of aluminum stearate [trade name, manufactured by Nippon Oil & Fats Co., Ltd .; aluminum stearate # 600] The above-mentioned raw materials were mixed and heated and stirred at 140 ° C. to dissolve aluminum stearate in a transparent state, and then cooled to room temperature to obtain an ink backflow preventer. 20 ° C of this ink backflow prevention body
Was 33 mm.

Comparative Example 2 Polybutene 99 parts [Nippon Oil Co., Ltd., trade name; polybutene 15H, viscosity 550 cSt (40 ° C.)] N lauroyl-acylated amino acid 1 part [Ajinomoto Co., trade name; GP- 1) The above-mentioned raw materials were mixed, heated and stirred at 150 ° C., and the N-lauroyl-acylated amino acid was dissolved in a transparent state, and then cooled to room temperature to obtain an ink backflow preventer. The SM value of this ink backflow preventer at 20 ° C. was 37 mm.

Comparative Example 3 95 parts of refined mineral oil [Mitsubishi Oil Corporation, trade name; diamond SN150 bright stock, viscosity 480 cSt (40 ° C.)] aluminum stearate 5 parts [manufactured by NOF Corporation, trade name; Aluminum Stearate # 900] The above raw materials were mixed, heated and stirred at 140 ° C., and aluminum stearate was dissolved in a transparent state, and then cooled to room temperature to obtain an ink backflow preventer. 20 ° C of this ink backflow prevention body
Was 30 mm.

Comparative Example 4 Ethylene-α-olefin cooligomer 99 parts [Mitsui Petrochemical Co., Ltd., trade name; Lucant HC-150, viscosity 2200c St (40 ° C.)] N lauroyl-acylated amino acid 1 part [Ajinomoto Product name: GP-1] The above-mentioned raw materials are mixed, heated and stirred at 150 ° C. to dissolve the N-lauroyl-acylated amino acid in a transparent state, and then cooled to room temperature to obtain an ink backflow preventer. . The SM value of the ink backflow preventer at 20 ° C. was 32 mm.

Comparative Example 5 95 parts of ethylene-α-olefin cooligomer [Mitsui Petrochemical Co., Ltd., trade name; Lucant HC-150, viscosity 2200 c St (40 ° C.)] Aluminum stearate 5 parts [Nippon Oil & Fats Co., Ltd. ), Trade name; aluminum stearate # 900] The above-mentioned raw materials were mixed, heated and stirred at 140 ° C., aluminum aluminum stearate was dissolved in a transparent state, and then cooled to room temperature. In this comparative example, the SM value was not measured because the gelation was insufficient as an ink backflow preventive.

Performance test 1 A performance test solution (transparent gel) having the following composition was placed in a 3.8 mm inner diameter polypropylene pipe having a stainless steel ballpoint pen tip holding a 0.7 mm diameter cemented carbide ball at the tip. Solutions) and Examples 1 to 3
A test writing instrument filled with the ink backflow preventers of Comparative Examples 1 to 5 was used. Performance test solution (“parts” represents “parts by weight”) polyvinyl alcohol 5.0 parts [manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name; Gohsenol GL-05] xanthan gum 0.5 parts [Dainippon Pharmaceutical Co., Ltd. ), Product name; echo gum]

Interface State Test The test writing implements filled with the respective ink backflow preventers and the performance test solution were allowed to stand upright and inverted at 50 ° C. for 7 days, and then visually observed as “test liquid-ink backflow preventer interface”. Was observed. Base oil separation test The test writing implement filled with each of the ink backflow preventers and the performance test solution was left standing at 50 ° C. for 30 days in an upright position.
The separation state of the base oil was visually observed.

The results of the interface state test and the base oil separation test are shown in the following table. In each test, the results were determined based on the following criteria. Interface state test 試 験: No abnormality is observed at the interface between the test liquid and the ink backflow prevention body. C: Slight collapse is observed at the interface between the test liquid and the ink backflow prevention body. ×: Clear collapse is observed at the interface between the test liquid and the ink backflow preventer. Base oil separation test ○: No separation of base oil was observed. Δ: Separation tendency of base oil is slightly observed. C: Part or all of the ink backflow preventer has moved into the test solution or the tip rear end position.

[0032]

[Table 1]

Performance test 2 The performance test solution filled in the above-mentioned writing instrument was prepared by adding 7 parts of carbon black as a coloring agent, 0.3 parts of xanthan gum as a shear-thinning agent, 0.2 parts of a polyether-modified silicone as an additive, and water. 92.5 parts were replaced with the mixed and stirred ink to prepare a test writing implement. Backflow resistance test Each of the above-mentioned ink backflow preventers and the test writing implement filled with the ink were dropped from a height of 4 feet in an upright state, and the state of the ink backflow preventers was visually observed. Each of the above-described ink backflow preventers and the test writing implement filled with the above-described ink was left standing at 50 ° C. for 30 days in an upright state, and then written to evaluate ink followability.

The results of the backflow resistance test and the aging follow-up test are shown in the following table. In each test, the results were determined based on the following criteria. Backflow resistance test ○: No abnormality is observed at the interface between the test liquid and the ink backflow prevention body. C: Slight collapse is observed at the interface between the test liquid and the ink backflow prevention body. ×: Backflow of the ink is observed. Follow-up test after aging ○: Ink follows without any problem. Δ: No problem in low-speed writing, but handwriting is interrupted in high-speed writing. X: Writing cannot be performed normally.

[0035]

[Table 2]

In Comparative Example 5, since the viscosity required for the ink backflow preventer did not reach the required value, the writing implement could not be assembled, and was excluded from the performance test.

[0037]

The present invention provides an α-olefin oligomer,
An ink comprising a first non-volatile liquid, a second non-volatile liquid, and a metal soap, which is a mixed solution of one or more selected from ethylene-α-olefin cooligomers and isoparaffin oil, is used as an ink. An ink backflow preventive for writing implements that satisfies the characteristics required for an ink backflow preventive, such as backflow prevention performance and high-speed writing followability, without being affected by components and without causing a change in viscosity or change in appearance over a long period of time. To provide.

Claims (8)

[Claims] 1. An ink backflow preventer disposed on a rear end face of ink directly housed in an ink housing cylinder of a writing instrument and advancing as ink is consumed, wherein the ink backflow preventer comprises at least an α-olefin oligomer, Ethylene-α-
An ink backflow preventive for a writing implement, comprising a first hard-volatile liquid, a second hard-volatile liquid, which is one or a mixed liquid of two or more selected from olefin cooligomers and isoparaffin oils, and a metal soap. Composition. 2. The ink backflow preventive composition for a writing instrument according to claim 1, wherein the second hardly volatile liquid is a good solvent for metal soap. 3. The ink backflow preventive composition for a writing instrument according to claim 1, wherein the second hardly volatile liquid is one or a mixture of two or more kinds selected from refined mineral oil and polybutene. object. 4. The ink backflow preventive composition for a writing instrument according to claim 1, wherein the metal soap is aluminum stearate. 5. The ink backflow preventive composition for a writing instrument according to claim 1, wherein the metal soap is added in an amount of 1 to 10% by weight. 6. The ink backflow prevention for a writing instrument according to claim 1, wherein a blending ratio (weight ratio) of the first hardly volatile liquid to the second hardly volatile liquid is 1 or more. Body composition. 7. The ink backflow preventive composition for a writing instrument according to claim 1, wherein the one-minute value measured with a spread meter (parallel plate viscometer) is 25 to 50 mm (measured value at 20 ° C.). . 8. The writing instrument according to claim 1, wherein the second hard-to-evaporate liquid is thickened with a metal soap before being mixed with the first hard-to-evaporate liquid. A method for producing an ink backflow preventive composition.