JP5628588B2 - Composition for forming ballpoint pen ink backflow preventer and method for forming ballpoint pen ink backflow preventer - Google Patents

Description

  The present invention relates to a composition for forming a ballpoint pen ink backflow preventive body (hereinafter also simply referred to as “composition for forming a backflow preventive body”) and a method for forming a ballpoint pen ink backflow preventive body (hereinafter simply referred to as “method for forming a backflow preventive body”). In detail, the ink contained in the ink containing tube is filled in contact with the rear end portion of the ink containing tube, has excellent followability with respect to the ink reduced by writing, and adheres to the inner wall of the ink containing tube. The present invention also relates to a composition for forming a backflow preventive body having a cleaning property that eliminates ink remaining on the inner wall of the containing tube and a method for forming the backflow preventive body.

  The composition for forming a backflow prevention body filled in the ink storage tube of the ballpoint pen leaks out from the rear end of the ink storage tube when the pen tip is stored or transported for a long time with the pen tip facing upward or horizontally. Ink backflow prevention performance to prevent this, cleaning performance to eliminate ink remaining on the inner wall of the receiving tube following ink reduction when writing, and ink scattering and ink outflow when the writing instrument body is dropped Impact resistance performance is required.

  Conventionally, as a composition for forming such a backflow preventive body, a base oil such as polybutene, α-olefin oil, refined mineral oil, silicone oil, silica powder, metal soap, bentonite, a styrene-butadiene elastomer, and a thickener are necessary. Depending on the case, various additives may be blended to form a gel (for example, Patent Documents 1 to 3).

  However, since these gel-like substances are solids but a mixture of base oil and thickener, they are easily deformed when subjected to strong impacts, and in long-term storage at high temperatures. Was softened and flowed out, and in any case, it could not function as a backflow preventer that completely prevented ink leakage.

  On the other hand, Patent Document 4 discloses a composition for forming a backflow preventer that can retain its shape without being deformed by a strong impact or softening even at high temperatures. This composition for forming a backflow preventive body uses a crosslinked product of hydrogen-modified organosiloxane and vinyl-modified polysiloxane, and is not simply a mixture like a conventional gel-like material but a polymer. Since the material undergoes a cross-linking reaction, it may have the characteristics as described above.

JP 2000-177288 A (paragraph [0003] etc.) JP 2000-301880 A (paragraph [0003] etc.) JP 2005-059526 A (paragraph [0003] etc.) JP 2004-074456 A (paragraph [0003] etc.)

  The backflow preventer using the cross-linked body described in Patent Document 4 needs to obtain a cross-linked body by heating and curing before filling into the ink containing tube because the cross-linking reaction is a heat curing mechanism. However, since the crosslinked body that has been cured once is not easily deformed, there is a problem that it is very difficult to fill the ink containing tube. Moreover, since this crosslinked body has adhesiveness and adheres to the inner wall surface of the ink containing tube, it has poor follow-up properties due to ink reduction by writing, and has a problem in cleaning properties.

  Therefore, the object of the present invention is to solve the problems of the conventional backflow preventive body, easily fill the ink containing tube, maintain the shape as the backflow preventive body even under strong impact and high temperature, and reduce ink by writing. Another object of the present invention is to provide a composition for forming a ballpoint pen ink backflow preventive body that is excellent in followability and a method for forming the formed body.

  In order to solve the problems of the conventional backflow preventer described above, the present inventors have intensively studied to form a crosslinked body by a curing reaction after filling the ink containing tube, and as a result, the curing reaction is caused by moisture in the air. Thus, the present inventors have found that the above problems can be solved by a combination of a condensation reaction curable silicone composition for forming a silicone-based crosslinked product and a hydrocarbon-based release agent, and have completed the present invention.

That is, the present invention comprises (A) a silanol group-terminated polyorganosiloxane, (B) the following general formula [II]
R ² _a SiX _4-a [II]
(Wherein R ² represents a substituted or unsubstituted monovalent hydrocarbon group, X represents an alkoxy group, and a is 1.)
The silane compound containing two or more hydrolyzable groups in the molecule and / or a cross-linking agent of the partial hydrolysis condensate thereof represented by the formula (A) with respect to 100 parts by mass of the silanol group-terminated polyorganosiloxane A composition for forming a ballpoint pen ink backflow preventer comprising 0.1 to 20 parts by mass , (C) a curing catalyst, and (D) a hydrocarbon-based release agent.

  In the present invention, the (A) silanol group-terminated polyorganosiloxane preferably has a viscosity at 25 ° C. in the range of 100 to 500,000 cSt.

  The crosslinking agent (B) is preferably an alkoxysilane compound containing two or more alkoxy groups in the molecule and / or a partial hydrolysis condensate thereof.

  Further, the (C) curing catalyst is preferably an organotin compound.

  Furthermore, the (D) hydrocarbon release agent is preferably a liquid material composed of saturated or unsaturated hydrocarbons having a viscosity at 25 ° C. in the range of 1 to 500,000 cSt.

  Further, the present invention provides an appropriate amount of the composition for forming a ballpoint pen ink backflow preventive body according to any one of claims 1 to 6 so as to contact the rear end of the ink contained in the ink containing tube of the ballpoint pen. It is a method for forming an ink backflow preventive body characterized in that a silicone-based cross-linked body is formed by filling and arranging and then cross-linking by a condensation curing reaction.

  According to the present invention, it is easy to fill an ink containing tube, can maintain a shape as a backflow preventive body even under strong impact or high temperature, and has excellent follow-up characteristics associated with ink reduction by writing. A composition for forming a body and a method for forming the formed body can be provided.

Hereinafter, embodiments of the present invention will be described in detail.
The composition for forming a backflow preventer of the present invention comprises (A) a silanol group-terminated polyorganosiloxane, and (B) a silane compound containing two or more hydrolyzable groups in the molecule and / or a partial hydrolysis condensate thereof. A crosslinking agent, (C) a curing catalyst, and (D) a hydrocarbon release agent.

（式中、Ｒ^１は不独立に非置換又は置換の一価の炭化水素基を表す。） Here, the silanol group-terminated polyorganosiloxane of the component (A) is represented by the following general formula [I], and preferably has a repeating unit number n in which the viscosity at 25 ° C. is in the range of 100 to 500,000 cSt.

(In the formula, R ¹ independently represents an unsubstituted or substituted monovalent hydrocarbon group.)

R ¹ is preferably a hydrocarbon group having 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms. For example, a lower alkyl group such as a methyl group, an ethyl group, a propyl group, or a butyl group, vinyl Groups, allyl groups, alkenyl groups such as isopropenyl groups, aryl groups, aralkyl groups, and groups in which some or all of the hydrogen atoms of these groups are substituted with halogen atoms, such as chloromethyl groups, trifluoropropyl groups Etc. In addition, these monovalent hydrocarbon groups R ¹ may have some of their hydrogen atoms substituted with hydroxyl groups, if necessary in terms of properties.

R ¹ is particularly preferably a methyl group, a phenyl group or a trifluoropropyl group, and more preferably a methyl group.

The crosslinking agent of the silane compound and / or its partially hydrolyzed condensate containing two or more hydrolyzable groups in the component (B) molecule is represented by the following general formula [II].
R ² aSiX _4-a [II]
(In the formula, R ² represents a substituted or unsubstituted monovalent hydrocarbon group, X represents a hydrolyzable group, and a is 0 or 1.)

Specific examples of R ² are the same as those described above for R ^1. Among them, a methyl group, an ethyl group, a propyl group, a butyl group, and a phenyl group are preferable. Examples of the hydrolyzable group of X include alkoxy groups such as methoxy group, ethoxy group, propoxy group and butoxy group, ketoxime groups such as methylethyl ketoxime group, alkenyloxy groups such as isopropenoxy group, acyloxy groups such as acetoxy group, dimethylamino An aminoxy group such as a xy group is exemplified, and an alkoxy group is preferable among them.

  Specific examples include methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, butyltriethoxysilane, vinyltrimethoxysilane, and partial hydrolysis condensates thereof. Alkoxysilanes are preferred.

  (B) The compounding quantity of a component becomes like this. Preferably it is 0.1-20 mass parts with respect to 100 mass parts of silanol group terminal polyorganosiloxane of (A) component, More preferably, it is 1-10 mass parts. When the blending amount of the component (B) is less than 0.1 parts by mass, the crosslinking point is insufficient, the curing does not proceed sufficiently, and the liquid remains in a liquid state. Cannot be obtained satisfactorily. On the other hand, when the amount is more than 20 parts by mass, there are too many cross-linking points, and the cross-linked product becomes harder than the intended gel state, so that the ink followability becomes insufficient.

  The component (C) curing catalyst is a catalyst for a crosslinking reaction for forming a silicone-based crosslinked product, preferably a carboxylic acid metal salt such as tin octoate, tin caprylate, tin oleate, or dimethyltin dipersate. And organic tin compounds such as dibutyltin dipersate. A tin compound containing 1 to 50% by weight as metal tin is suitably used as the curing catalyst. In addition to the tin compound curing catalyst, various known titanium chelate compounds such as diisopropoxy bis (ethyl acetoacetate) titanium and diisopropoxy bis (ethyl acetoacetate) using titanium metal are preferably used.

  The amount of component (C) is preferably 0.01 to 10 parts by weight, more preferably 0.1 to 5 parts by weight, based on 100 parts by weight of the silanol group-terminated polyorganosiloxane of component (A). More preferably, it is 0.2-4 mass parts. When the blending amount of the component (C) is less than 0.01 parts by mass, the curability becomes insufficient and the stickiness comes out, so that it adheres to the inner wall of the ink containing tube and the follow-up property of the backflow preventer becomes insufficient. . On the other hand, if the amount is more than 10 parts by mass, the curability is too good and the silicone-based crosslinked product becomes harder than the intended gel state. Furthermore, since the curing reaction is too early and the curing reaction is completed before the carbon-based release agent is separated from the silicone-based component and oozes out, good followability of the backflow preventer cannot be obtained.

The (D) component hydrocarbon-based mold release agent is preferably a liquid material comprising a saturated or unsaturated hydrocarbon having a viscosity at 25 ° C. of 1 to 500,000 cSt, more preferably 5 cSt to 10,000 cSt. is there. The hydrocarbon of component (D) is contained in the ink when the silicone-based crosslinked body, which is the main component of the composition for forming a backflow preventer, separates from the main component during and after the curing reaction and oozes out to the surface. It mix | blends in order to provide the effect which prevents adhesion to a pipe inner wall surface to the composition for backflow prevention body formation of this invention.
Component (D) is preferably blended in an amount of 100 parts by mass of the silanol group-terminated polyorganosiloxane of component (A). It is 1-30 mass parts, More preferably, it is 5-20 mass parts. If the amount of component (D) is less than 1 part by mass, the amount of component (D) separated from the composition for forming a backflow preventer becomes insufficient, and the composition for forming a backflow preventer adheres to the inner wall of the ink containing tube. However, the followability becomes insufficient. On the other hand, when the amount is more than 30 parts by mass, separation begins before curing, and separation from the silanol group-terminated polyorganosiloxane of component (A) occurs. Moreover, after hardening, the amount of separation from the composition for forming a backflow prevention body increases and may be mixed into the ink.

  When the viscosity of such a hydrocarbon-based release agent is less than 1 cSt, the viscosity is too low, so that the separability is large, and it may be separated from the backflow inhibitor after curing and mixed into the ink. On the other hand, if it exceeds 500,000 cSt, the separability deteriorates and it is difficult to separate from the composition for forming a backflow preventer, so that the backflow preventive agent adheres to the inner wall of the ink containing tube and the followability becomes insufficient.

Component (D) is a hydrocarbon-based mold release agent having a general formula of C _n H _{2n + 2,} which is a liquid alkene at room temperature, specifically, white oil, white mineral oil, water paraffin, mineral oil, mineral oil. Examples thereof include white and medical paraffin. Further, it may be a poly-α-olefin, which is a polyolefin synthesized from an olefin having an unsaturated group, a reaction product of ethylene and α-olefin, polyphten, or the like.

  In the present invention, in addition to the components (A) to (D) described above, various additives can be blended in order to improve the properties of the composition as long as the object of the present invention is not impaired. For example, in order to control the fluidity of the composition, silicone oils such as dimethylpolysiloxane and methylphenylpolysiloxane having a viscosity at 25 ° C. in the range of 100 to 500,000 cSt, or fumed silica, precipitated silica and The thing etc. which hydrophobized them can be mix | blended. Further, quartz powder, fused quartz, spherical silica, diatomaceous earth, zeolite, calcium carbonate, titanium dioxide, iron oxide, alumina, alumina hydroxide, etc. can be blended as fillers or extenders. Further, various colorants can be blended for coloring as required. In order to promote curability, it is optional to add water or alcohols such as methanol, ethanol, propanol, and methyl cellosolve.

  The composition for forming a backflow prevention body of the present invention can be obtained by, for example, uniformly mixing using a mixer such as a planetary mixer, a universal kneader, or a trimix. The obtained mixture can be satisfactorily obtained in a desired cross-linked form by allowing it to stand at room temperature in an environment of 50% humidity for at least 24 hours. Further, in order to completely cure to a thickness of 10 mm or more, it is necessary to leave it for 48 hours or more.

  Hereinafter, the present invention will be described in detail with reference to examples. However, the present invention is not limited to the following examples. In Examples, “part” means “part by mass” and “viscosity” means kinematic viscosity at 25 ° C.

Example 1
100 parts of dimethylpolysiloxane (viscosity: 3,000 cSt) sealed at both ends with silanol groups, 5 parts of methyltriethoxysilane, and 50 parts of dimethylpolysiloxane (viscosity: 3,000 cSt) are mixed well. Further, 10 parts of liquid paraffin (viscosity at 40 ° C. of 40 cSt) was blended and mixed well until uniform. Thereafter, 1 part of dioctyltin acetylacetate was added, and after mixing well, defoaming treatment was performed to obtain a composition for forming a backflow preventer of Example 1.

Example 2
In order to prevent separation of liquid paraffin as a release agent and to prevent outflow when the ink storage tube is stored obliquely immediately after filling the ink storage tube, the specific surface area by the BET method is increased before the defoaming treatment. A backflow prevention body-forming composition of Example 2 was obtained in the same manner as in Example 1 except that 4 parts of 200 m ² of finely divided silica powder were blended.

Comparative Example 1
Compound 100 parts of dimethylpolysiloxane (viscosity: 3,000 cSt) is mixed with 8 parts of silica powder hydrophobized to fine powder silica powder having a specific surface area of 200 m ² by BET method. Foam treatment was performed to obtain a composition for forming a backflow preventer as Comparative Example 1.

Comparative Example 2
100 parts of dimethylpolysiloxane (viscosity: 3,000 cSt) is blended with 5 parts of silica powder hydrophobized to fine powder silica powder having a specific surface area of 200 m ² according to the BET method. Foam treatment was performed to obtain a composition for forming a backflow preventer as Comparative Example 2.

Comparative Example 3
Blend 100 parts of ethylene-α-olefin copolymer with a viscosity of 100 cSt at 100 ° C and 5 parts of silica powder hydrophobized into fine silica powder with a specific surface area of 200 m ² by BET method, and mix evenly with 3 rolls. Then, the defoaming process was performed and the composition for backflow prevention body formation as the comparative example 3 was obtained.

Comparative Example 4
5 parts of 12 hydroxy lithium stearate is blended with 100 parts of an α-olefin copolymer having a viscosity at 100 ° C. of 6 cSt, dissolved by heating, cooled, uniformly mixed and stirred with three rolls, and defoamed. A composition for forming a backflow preventer as Comparative Example 4 was obtained.

Comparative Example 5
A commercially available silicone gel TSE3062 in which a platinum catalyst was blended with dimethylpolysiloxane having both ends sealed with vinyl groups and dimethylpolysiloxane having a hydrogen group was used. After mixing 50 parts of TSE3062 (A) trade name and 50 parts of TSE3062 (B) well by Momentive Co., defoaming treatment was performed, followed by overheating at 50 ° C. for 24 hours to form a backflow preventive body as Comparative Example 5. A composition was obtained. In addition, when it was 150 degreeC, it hardened | cured in 1 hour.

Comparative Example 6
Mix 100 parts of dimethylpolysiloxane (viscosity: 3,000 cSt) sealed at both ends with silanol groups, 5 parts of methyltriethoxysilane, and 50 parts of dimethylpolysiloxane (viscosity: 3,000 cSt) until uniform. Mix well. Thereafter, 1 part of dioctyltin acetylacetate was added, and after mixing well, defoaming treatment was performed to obtain a composition for forming a backflow preventer as Comparative Example 6.

Performance test Water-based ink for ballpoint pens is injected into a polypropylene ink storage tube with an internal diameter of 3.8 mm with a stainless steel ballpoint pen tip with a 0.7 mm ball at the tip, and contacts the rear end of this ink. Thus, the backflow preventive body forming compositions of Examples 1 and 2 and Comparative Examples 1 to 6 were filled and arranged so as to be 15 mm from the interface with the ink, and various tests shown below were conducted. It was.
The compositions for forming a backflow preventive body of Example 1 and Example 2 were filled in an ink containing tube and allowed to stand at room temperature for 24 hours to form a silicone cross-linked body by condensation curing reaction and used for various tests.

(Ink followability test)
Writing was performed at a speed of about 40 cm / second, and it was observed whether or not the backflow prevention body followed as the ink was consumed. A backflow preventer that follows well with ink consumption and that can be written normally is judged as acceptable (○), and poorly tracked and partially unable to form handwriting. Those that could not be evaluated were rejected (x).

(Visibility test)
After the ink follow-up test, the state of the ink adhering to the inner wall of the ink containing tube and the state of the backflow preventer was visually observed when the ink decreased to about half the position of the ink containing tube. The case where the ink and the backflow preventive body were not attached to the inner wall surface of the ink containing tube was evaluated as acceptable (◯), and the case where the ink and a part of the backflow preventive body were adhered was determined as unacceptable (x).

(Ink following test after 1 day)
After being allowed to stand at room temperature for 1 day, writing was performed at a speed of about 40 cm / second, and it was observed whether the backflow preventer would follow as the ink was consumed. A backflow preventer that satisfactorily followed as the ink was consumed and was able to write normally was evaluated as pass (◯), and a sample that was poorly tracked and could not be partially or completely formed was rejected (x).

(Visibility test after 1 day)
After the ink follow-up test after 1 day, the state of the ink adhering to the inner wall of the ink containing tube and the state of the backflow preventer when the ink decreased to about half the position of the ink containing tube was visually observed. The case where the ink and the backflow preventive body were not attached to the inner wall surface of the ink containing tube was evaluated as acceptable (◯), and the case where the ink and a part of the backflow preventive body were adhered was determined as unacceptable (x).

(Impact resistance test)
After holding the pen tip by hand and dropping it 10 times from a height of 1 m onto the concrete floor, the state of the ink and the backflow preventer was visually observed. A part of the ink in the backflow preventive body, conversely, a part of the backflow preventive body that was observed to move in the ink was rejected (x), and a case in which these phenomena were not observed passed ( ○).

(Separability test)
The nib was sealed with a cap and left standing in a constant temperature bath at 50 ° C. for one month, and the state of the backflow preventer was visually observed. In comparison with the initial stage, a case where there was no oil separation or a change in state was determined as pass (◯), and a case where oil separation or a change in state occurred was determined as failure (x).

(Ink follow-up test after 1 month)
After being left in a thermostatic bath at 50 ° C. for one month, writing was performed at a speed of about 40 cm / second, and it was observed whether the backflow preventer followed up with ink consumption. A backflow preventer that satisfactorily followed as the ink was consumed and was able to write normally was evaluated as pass (◯), and a sample that was poorly tracked and could not be partially or completely formed was rejected (x).

  The results of the performance test are shown in Table 1 below.

＊１：硬さ（針入度）は、ＪＩＳＫ２２２０の１／４ちょう度計を用いて、試料の表面から１／４円すいが落下した深さを直読し、その値を１０倍にした値である。実施例１、実施例２及び比較例６は、室温にて４８時間放置後の値であり、比較例２〜４は、室温にて２４時間放置後の値であり、比較例５は、５０℃にて２４時間加熱硬化後の値である。

* 1: Hardness (penetration) is a value obtained by directly reading the depth at which the 1/4 cone was dropped from the surface of the sample using a JISK2220 1/4 consistency meter and multiplying that value by 10 times. is there. Examples 1, 2 and 6 are values after standing at room temperature for 48 hours, Comparative Examples 2 to 4 are values after standing at room temperature for 24 hours, and Comparative Example 5 is 50 It is a value after 24 hours of heat curing at ° C.

Claims (7)

In the composition for forming a ballpoint ink backflow preventer that is filled in the rear end of the ink stored in the ink storage tube and follows as the ink is consumed.
(A) a silanol group-terminated polyorganosiloxane;
(B) The following general formula [II]
R ² _a SiX _4-a [II]
(Wherein R ² represents a substituted or unsubstituted monovalent hydrocarbon group, X represents an alkoxy group, and a is 1.)
The silane compound containing two or more hydrolyzable groups in the molecule and / or a cross-linking agent of the partial hydrolysis condensate thereof represented by the formula (A) with respect to 100 parts by mass of the silanol group-terminated polyorganosiloxane 0.1 to 20 parts by mass ;
(C) a curing catalyst;
(D) a hydrocarbon release agent;
A composition for forming a ballpoint ink backflow preventive body, comprising:   2. The composition for forming a ballpoint ink backflow preventer according to claim 1, wherein the (A) silanol group-terminated polyorganosiloxane has a viscosity at 25 ° C. of 100 to 500,000 cSt.   The composition for forming a ballpoint ink backflow preventer according to claim 1 or 2, wherein the crosslinking agent (B) is an alkoxysilane compound containing two or more alkoxy groups in the molecule and / or a partial hydrolysis condensate thereof. .   The said (D) hydrocarbon type mold release agent is a liquid substance which consists of a saturated or unsaturated hydrocarbon in which the viscosity in 25 degreeC is the range of 1-500,000 cSt. The composition for ball-point pen ink backflow prevention body description of description.   The composition for forming a ballpoint pen ink backflow preventer according to any one of claims 1 to 4, wherein the hydrocarbon release agent (D) is liquid paraffin.   Furthermore, the composition for ball-point pen ink backflow prevention body formation as described in any one of Claims 1 thru | or 5 which mix | blended the silica powder.   An appropriate amount of the composition for forming a ballpoint ink backflow preventive body according to any one of claims 1 to 6 is filled and arranged so as to come into contact with the rear end of the ink stored in the ink storage tube of the ballpoint pen, and then condensed. A method for forming an ink backflow preventive, characterized in that a silicone-based crosslinked product is formed by crosslinking by a curing reaction.