JP2006152011A - Surface-treating composition, rubber surface-treating method, and manufacturing method of relief valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide (1) a surface-treating composition capable of stably imparting non-stickiness and other properties to the rubber surface and (2) a manufacturing method of a low-pressure relief valve suffering from no large deviation of the working pressure from the set pressure (the working pressure before left) even after left in a closed state for long hours. <P>SOLUTION: The surface-treating composition comprises a specific fluorocompound, a tetraalkoxysilane, a tetraalkoxytitanium, a silane coupling agent and a solvent. The manufacturing method of the low-pressure relief valve having a valve body equipped with an O ring touching and parting from the valve seat comprises a step for coating the O ring with the surface-treating composition and heating the coating film of the composition to surface-treat the O ring and a step for attaching the surface-treated O ring as a constituting part of the valve body. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a surface treatment composition, a rubber surface treatment method, and a relief valve manufacturing method, and more particularly, a surface treatment composition capable of stably imparting characteristics such as non-adhesiveness to a rubber surface. The present invention also relates to a rubber surface treatment method and a method of manufacturing a low pressure relief valve having a valve body having an O-ring contacting and separating from a valve seat and operating at a pressure of 100 KPa or less.

Conventionally, a method of treating the surface of various articles with a fluorine-containing compound having a fluoroalkyl group at both ends and a functional group (functional group including a hydrolyzable group) such as a trimethoxysilyl group bonded to an intermediate chain It has been known.
In such a fluorine-containing compound, the fluoroalkyl groups at both ends of the molecule are bonded to the intermediate chain through covalent bonds, and surface characteristics (for example, non-adhesiveness and water / oil repellency) due to fluorine atoms are imparted to the material surface. can do.

As a method of treating the surface of an article made of an inorganic material such as glass or metal with a fluorine-containing compound as described above, a fluorine-containing compound in which a silicon atom having three hydrolyzable groups is bonded to an intermediate chain is used. The monomer solution containing this is applied to the surface of the article to be treated, and the surface treatment layer (mainly containing the fluorine-containing cross-linked polysiloxane) is produced on the surface of the article to be treated by allowing hydrolysis and condensation reaction of the fluorine-containing compound to proceed. A method for forming a coating film as a component has been introduced (for example, see Patent Document 1).
Further, this Patent Document 1 discloses that the heat resistance of a film to be formed is improved by containing a trifunctional or tetrafunctional alkoxysilane as a constituent component of the monomer solution.

Thus, it would be desirable to be able to treat the rubber surface using a fluorine-containing compound as described above.
However, the surface treatment layer (coating containing fluorine-containing crosslinked polysiloxane as a main component) formed on the rubber surface by the method described in Patent Document 1 has sufficient adhesion (bonding force) to rubber which is an organic substance. And may be detached from the rubber (base material).
Further, when an organic solvent is brought into contact with the rubber product surface-treated by such a method, a part of the fluorine-containing crosslinked polysiloxane is dissolved in the organic solvent and flows out of the surface treatment layer. The imparted surface properties (for example, non-adhesiveness and water / oil repellency) are greatly reduced. As a result, the rubber product surface-treated by the method described in Patent Document 1 cannot be used for applications where solvent resistance is required.
Further, various rubber products are required to improve non-adhesiveness (further reduction in adhesive strength).

As equipment (pneumatic equipment) equipped with a rubber product that requires non-adhesiveness as a component (pneumatic equipment), when the pressure of the pressurized fluid in the pipeline exceeds a certain value, Relief valves, which are pressure regulating valves that are released to atmospheric pressure) are widely used, and the present applicant has also proposed relief valves having various structures (see, for example, Patent Document 2 and Patent Document 3).
The relief valve generally includes a valve seat (fixed portion), a valve body (movable portion), a spring that presses the valve body against the valve seat, and a compression means for the spring.
The valve body, which is a movable part of the relief valve, is provided with an O-ring (rubber part) that comes into contact with and separates from the valve seat, thereby ensuring airtightness with the valve seat when the valve is closed.
The operating pressure of the relief valve, that is, the pressure when the pressurized fluid is released by opening the valve depends on the urging force (force to press the valve body against the valve seat) by the spring constituting the relief valve. For example, if the biasing force by the spring is F and the pressure receiving area of the valve body that receives the pressure of the pressurized fluid is A, the pressure is increased when the pressure of the pressurized fluid rises to (F / A) or more. The valve element separates (opens) from the valve seat against the force (F), and the pressurized fluid is released.
Here, the biasing force (F) by the spring can be adjusted by appropriately changing the compression amount of the spring by the compression means.
The operating pressure set to the relief valve (hereinafter referred to as “set pressure”) varies depending on the specification of the pipe line (pneumatic circuit) to which the relief valve is mounted, and operates at a pressure of 100 KPa or less in various applications. Therefore, a relief valve for low pressure is desired.

However, if the relief valve as described above is left in a closed state (a state in which the O-ring constituting the valve body and the valve seat are in contact) for a certain period of time (for example, 1 hour or more), the O-ring is placed on the valve seat. As a result, the valve body becomes difficult to be separated (opened) from the valve seat, and as a result, there is a problem that the relief valve does not operate even if the pressure in the pipeline exceeds the set pressure.
In particular, in a low pressure relief valve with a small urging force by a spring, its operating pressure is easily affected by adhesion of an O-ring. For example, the relief valve does not operate even when the pressure rises to 1.5 times or more of a set pressure. Sometimes.
JP 2002-338691 A JP 2000-97369 A JP 2000-170934 A

The present invention has been made based on the above situation.
A first object of the present invention is to provide a surface treatment composition and a rubber surface treatment method capable of stably imparting properties such as non-adhesiveness to the rubber surface.
The second object of the present invention is to provide a surface treatment composition and a rubber surface treatment method capable of forming a surface treatment layer having high adhesion to rubber.
A third object of the present invention is to provide a surface treatment composition capable of forming a surface treatment layer having good solvent resistance and imparting surface properties that are not impaired even by solvent washing to the surface of the rubber. An object of the present invention is to provide a rubber surface treatment method.
A fourth object of the present invention is to provide a low pressure relief valve manufacturing method in which the operating pressure after being left is not changed greatly from the set pressure (the operating pressure before being left) even after being left in a closed state for a long time. Is to provide.

The composition of the present invention is a composition for treating the surface of rubber, and contains a fluorine-containing compound represented by the following formula (F1) (hereinafter referred to as “specific fluorine-containing compound”) and the formula (1). ): Si (OR ⁴ ) ₄ (wherein R ⁴ represents an alkyl group having 1 to 4 carbon atoms), and formula (2): Ti (OR ⁵ ) ₄ (wherein , R ⁵ represents an alkyl group having 2 to 4 carbon atoms) and a formula (3): Si (OR ⁶ ) _m R ⁷ _3-m — (CH ₂ ) _n —R ⁸ (In the formula, R ⁶ represents an alkyl group or an alkoxyalkyl group, R ⁷ represents an alkyl group, m is an integer of 1 to 3, n is an integer of 0 to 5, and R ⁸ is This represents an organic functional group having reactivity with the polymer main chain of the rubber.) Characterized in that it contains a solvent.

(Wherein R _F represents a group containing a fluoroalkyl group, R ¹ represents an alkyl group or an alkoxyalkyl group, and R ² and R ³ represent the same or different hydrogen atoms or monovalent organic groups. X is an integer from 1 to 100, and y is an integer from 0 to 100.)

In addition, the composition of the present invention is a composition for treating the surface of rubber, and a specific fluorine-containing compound represented by the following formula (F2): Formula (1): Si (OR ⁴ ) ₄ ( In the formula, R ⁴ represents an alkyl group having 1 to 4 carbon atoms.) And a formula (2): Ti (OR ⁵ ) ₄ (wherein R ⁵ represents 2 to 2 carbon atoms). . representing 4 alkyl) and tetraalkoxy titanium represented by the formula ^{(3): Si (OR 6} ) m R 7 3-m - (CH 2) n -R 8 ( wherein, R ⁶ is an alkyl group Or an alkoxyalkyl group, R ⁷ represents an alkyl group, m is an integer of 1 to 3, n is an integer of 0 to 5. R ⁸ is a reactivity with a polymer main chain of rubber. A silane coupling agent represented by (2) and a solvent for dissolving them. To.

(In the formula, R _F represents a group containing a fluoroalkyl group, R ¹ represents an alkyl group or an alkoxyalkyl group, and x is an integer of 1 to 100.)

In the composition of the present invention, the following forms are preferable.
[1] In the formula (F1) or the formula (F2), the group containing a fluoroalkyl group represented by R _F is —CF ₃ , —C ₂ F ₅ , —C ₃ F ₇ , —C _6. A group represented by F ₁₃ , —C ₇ F ₁₅ or —CF (CF ₃ ) [OCF ₂ CF (CF ₃ )] _p OC ₃ F ₇ (wherein p is 0, 1 or 2). There is.
[2] The tetraalkoxysilane is tetramethoxysilane or tetraethoxysilane.
[3] The tetraalkoxytitanium is at least one selected from tetraethoxytitanium, tetra-iso-propoxytitanium and tetra-n-butoxytitanium.
[4] Containing an acid.
[5] A specific fluorine-containing compound represented by the above formula (F2), tetraethoxysilane, tetraethoxytitanium, a silane coupling agent, an acid, and an organic solvent.
[6] To contain tetraethoxytitanium having a mass of 0.01 to 0.1 times the content of tetraethoxysilane.
[7] 0.001 to 20% by mass of the specific fluorine-containing compound, tetraethoxysilane having a mass of 0.5 to 1000 times that of the specific fluorine-containing compound, and 0.001 to 20 times that of the specific fluorine-containing compound ( However, tetraethoxy titanium having a mass of 0.01 to 0.1 times that of tetraethoxysilane, a silane coupling agent having a mass of 0.01 to 10 times that of the specific fluorine-containing compound, hydrochloric acid, and an organic solvent Containing.
[8] 0.005 to 10% by mass of a specific fluorine-containing compound, tetraethoxysilane having a mass of 1 to 500 times that of the specific fluorine-containing compound, and 0.1 to 10 times that of the specific fluorine-containing compound (however, Tetraethoxy titanium having a mass of 0.02-0.1 times that of tetraethoxysilane, a silane coupling agent having a mass of 0.05-5 times that of a specific fluorine-containing compound, hydrochloric acid, and an organic solvent To do.
[9] 0.01 to 5% by mass of a specific fluorine-containing compound, tetraethoxysilane having a mass of 1 to 100 times that of the specific fluorine-containing compound, and 0.1 to 5 times that of the specific fluorine-containing compound (however, Containing tetraethoxytitanium having a mass of 0.02 to 0.1 times that of tetraethoxysilane, a silane coupling agent having a mass of 0.1 to 5 times that of a specific fluorine-containing compound, hydrochloric acid, and an organic solvent To do.

  The surface treatment method of the present invention comprises a step of applying the surface treatment composition of the present invention to a rubber surface and a step of heating a coating film by the surface treatment composition. The surface treatment method of the present invention is preferably applied to the surface of nitrile rubber.

A method for manufacturing a relief valve according to the present invention is a method for manufacturing a low-pressure relief valve that has a valve body having an O-ring that contacts and separates from a valve seat and operates at a pressure of 100 KPa or less. The step of applying the surface treatment composition of the invention to the O-ring, the step of surface-treating the O-ring by heating the coating film of the surface treatment composition, and the structure of the valve body of the surface-treated O-ring And a step of mounting as a component.
The relief valve obtained by the production method of the present invention preferably operates (releases pressurized fluid) at a pressure of 50 KPa or less, particularly 40 KPa or less.

(1) The specific fluorine-containing compound constituting the composition of the present invention has a plurality of hydrolyzable groups (—OR ¹ ) in the molecule, and the tetraalkoxysilane has four alkoxy groups ( has a -OR ^4), tetraalkoxy titanium also has four alkoxy groups (-OR ⁵⁾ in the molecule. The silane coupling agent has a hydrolyzable group (—OR ⁶ ) and a reactive organic functional group (—R ⁸ ) in the molecule.
The composition of the present invention is applied to the surface of a rubber to be treated, and a specific fluorine-containing compound, tetraalkoxysilane, tetraalkoxytitanium, and a silane coupling agent are reacted (hydrolyzed) on the surface of the rubber. By the decomposition / condensation reaction, a surface treatment layer composed of a hybrid compound (a compound containing fluorine atoms and having a SiO ₂ —TiO ₂ cross-linked structure) is formed, and this surface treatment layer (hybrid compound) is formed. Due to the fluorine atoms and the crosslinked structure, excellent surface characteristics (for example, non-adhesiveness, lubricity, abrasion resistance, water and oil repellency, etc.) are stably imparted to the rubber surface. In particular, the surface-treated layer having a SiO ₂ —TiO ₂ -based crosslinked structure is non-adhesive compared to a surface-treated layer having a SiO ₂ -based crosslinked structure (a surface-treated layer made of fluorine-containing crosslinked polysiloxane). The imparting effect (adhesive strength reducing effect) is remarkably excellent.

(2) In the hybrid compound (or the structure in the formation process) constituting the surface treatment layer formed by the composition of the present invention, a reactive organic functional group (—R ⁸ ) derived from the silane coupling agent This organic functional group (—R ⁸ ) reacts with the polymer main chain of the rubber near the surface of the workpiece. Thus, the surface treatment layer (hybrid compound) is chemically bonded to the polymer main chain of the rubber via the silane coupling agent.
Thus, since a chemical bond is formed between the surface treatment layer made of the hybrid compound and the polymer main chain of the rubber via the silane coupling agent, the surface treatment layer is made of organic matter. It adheres firmly to a certain rubber (object to be treated).
Therefore, the surface treatment layer is not detached in the use environment, and the imparted surface characteristics are stably expressed.

(3) The surface treatment layer (hybrid compound) bonded to the rubber polymer main chain via a silane coupling agent is excellent in thermal stability and chemical stability, and is a good solvent for a specific fluorine-containing compound. It becomes insoluble or hardly soluble in various organic solvents. As a result, even when an organic solvent is brought into contact with the rubber product (surface treatment layer) surface-treated with the composition of the present invention, a part of the hybrid compound does not elute, and the surface characteristics imparted thereby are substantially reduced. Will not be damaged. Therefore, the rubber product provided with the surface treatment layer (rubber product subjected to the treatment according to the present invention) has excellent solvent resistance.

(4) Since the relief valve obtained by the manufacturing method of the present invention has extremely low adhesiveness of the O-ring constituting the valve, the operating pressure after being left for a long time in the closed state However, there is no significant change from the set pressure (operating pressure before leaving).
Moreover, according to the relief valve obtained by the production method of the present invention, the surface treatment layer formed on the O-ring can be obtained even if the valve opening / closing operation including leaving the valve in a closed state for a long time is repeated many times. There is no peeling, and the performance (non-adhesiveness) of the surface treatment layer can be stably expressed over a long period of time, and the operating pressure does not change greatly from the set pressure.

Hereinafter, the present invention will be described in detail. <Surface treatment composition>
The composition of the present invention comprises a specific fluorine-containing compound, tetraalkoxysilane, tetraalkoxytitanium, a silane coupling agent, and a solvent.
Hereinafter, each component will be described.

(1) Specific fluorine-containing compound:
The specific fluorine-containing compound constituting the composition of the present invention has a group (R _F ) containing a fluoroalkyl group at both molecular ends and a group (trialkoxysilyl group) represented by —Si (OR ¹ ) _3. Alternatively, it is a fluorine-based oligomer having an intermediate chain formed by bonding a trialkoxyalkoxysilyl group) and further having an intermediate chain represented by (—CH ₂ —CR ² R ³ —).

Specific examples of the group (R _F ) containing a fluoroalkyl group constituting the specific fluorine-containing compound include —CF ₃ , —C ₂ F ₅ , —C ₃ F ₇ , —C ₆ F ₁₃ and —C _7. fluoroalkyl group represented by -C like _{F 15 q F 2q + 1 (} q = 1~10); -CF (CF 3) OC 3 F 7, -CF (CF 3) [OCF 2 CF (CF 3) ] Exemplifying a group represented by OC ₃ F ₇ and —CF (CF ₃ ) [OCF ₂ CF (CF ₃ )] ₂ OC ₃ F ₇ (a group containing an oxyfluoroalkylene group and a fluoroalkyl group) Among these, a group represented by —CF (CF ₃ ) OC ₃ F ₇ is particularly preferable.

Specific examples of the group represented by —Si (OR ¹ ) ₃ having an essential intermediate chain constituting a specific fluorine-containing compound include trialkoxysilyl groups such as trimethoxysilyl group and triethoxysilyl group; tri (methoxy Mention may be made of trialkoxyalkoxysilyl groups such as methoxy) silyl group, tri (methoxyethoxy) silyl group, tri (ethoxymethoxy) silyl group and tri (ethoxyethoxy) silyl group. Of these, trialkoxysilyl groups are preferred, and trimethoxysilyl groups are particularly preferred.

The groups (R ² , R ³ ) constituting any intermediate chain (—CH ₂ —CR ² R ³ —) in a specific fluorine-containing compound are the same or different groups, and are hydrogen atoms or monovalent organic groups Thus, an appropriate group can be selected according to the function to be imparted to the surface of the rubber. Examples of the organic group represented by R ² or R ³ include groups represented by the following formulas (i) to (v).

In the above formula (F1) showing a specific fluorine-containing compound, the number (x) of essential intermediate chains is 1 to 100, preferably 1 to 50, more preferably 1 to 10, particularly preferably 2 to 5. Is done.
Moreover, the number (y) of arbitrary intermediate chains is 0 to 100, preferably 0 to 50, and more preferably 0 to 10.

  Examples of suitable compounds constituting the specific fluorine-containing compound include compounds represented by the following formulas (4) to (8). In particular, a compound represented by the following formula (4) or formula (5) (a compound in which y = 0 in the above formula (F1)) is a fluorine atom (atom contributing to improvement in surface characteristics) in one molecule. Therefore, it is preferable because fluorine atoms can be present with high efficiency in the vicinity of the surface of the rubber base material.

(Wherein x 'is 2 or 3)

[In Formula (5) and Formula (6), R _F ′ is a group represented by the formula: —CF (CF ₃ ) OCF ₂ CF (CF ₃ ) OC ₃ F ₇ .
In formula (5), xa is an integer of 1-100.
In formula (6), xb is an integer of 1 to 100, and yb is an integer of 1 to 500. ]

[In Formula (7), xc is an integer of 1-10, yc is an integer of 0-100. In formula (8), xd is an integer of 1 to 10, and yd is an integer of 0 to 100. ]

In the presence of a fluorine-containing peroxide represented by the following formula (F1A), the specific fluorine-containing compound represented by the above formula (F1), the monomer represented by the following formula (F1B), and the following formula (F1C ) Can be obtained by polymerizing with a monomer represented by
In this reaction product (fluorine-containing compound), an oligomer in which a group (R _F ) containing a fluoroalkyl group is introduced only at one end may be contained in an arbitrary ratio.

(Wherein R _F , R ¹ , R ² and R ³ are as defined above.)

  The content ratio of the specific fluorine-containing compound in the composition of the present invention is preferably 0.001 to 20% by mass, more preferably 0.005 to 10% by mass, and particularly preferably 0.01 to 5% by mass. %. When the content ratio of the specific fluorine-containing compound is too small, it is difficult to impart a treatment effect (surface characteristics such as non-adhesiveness and water / oil repellency) to the rubber surface. On the other hand, even if a specific fluorine-containing compound is contained in a proportion exceeding 20% by mass, a treatment effect commensurate with the content cannot be obtained.

(2) Tetraalkoxysilane:
The tetraalkoxysilane constituting the composition of the present invention is a tetrafunctional alkoxysilane represented by the formula (1): Si (OR ⁴ ) ₄ .
In the formula (1) indicating tetraalkoxysilane, R ⁴ represents an alkyl group having 1 to 4 carbon atoms such as a methyl group, an ethyl group, a propyl group, or a butyl group. Specific examples of the tetraalkoxysilane include tetramethoxysilane (TMOS) and tetraethoxysilane (TEOS), and TEOS is particularly preferable.

The content of tetraalkoxysilane in the composition of the present invention is preferably 0.5 to 1000 times (mass), more preferably 1 to 500 times, particularly preferably the content of the specific fluorine-containing compound. 1 to 100 times.
When the content ratio of tetraalkoxysilane (relative ratio with respect to a specific fluorine-containing compound) is too small, formation of a crosslinked structure becomes insufficient, and it is difficult to completely cover the surface of the rubber (base material). Become.
On the other hand, if this ratio is excessive, it tends to be difficult to impart the desired treatment effect to the rubber surface.

(3) Tetraalkoxy titanium:
The tetraalkoxytitanium constituting the composition of the present invention is a tetrafunctional alkoxytitanium represented by the formula (2): Si (OR ⁵ ) ₄ .
By containing tetraalkoxytitanium as an essential component of the composition of the present invention, a surface treatment layer (SiO ₂ —TiO ₂ -based crosslinked structure having excellent non-tackiness imparting effect (adhesive strength reducing effect) is obtained. Having a hybrid compound).

In the above formula (2) indicating tetraalkoxytitanium, R ⁵ represents an alkyl group having 2 to 4 carbon atoms such as an ethyl group, an iso-propyl group, or an n-butyl group. Specific examples of the tetraalkoxysilane include tetraethoxytitanium, tetra-iso-propoxytitanium, and tetra-n-butoxytitanium, and tetraethoxytitanium is particularly preferable.

The content of tetraalkoxytitanium in the composition of the present invention is preferably 0.001 to 20 times (mass) of the content of the specific fluorine-containing compound, more preferably 0.1 to 10 times, particularly Preferably it is 0.1 to 5 times.
Further, the content of tetraalkoxytitanium is preferably 0.01 to 0.1 times, more preferably 0.02 to 0.1 times that of tetraethoxysilane.
When the content ratio of tetraalkoxy titanium (relative ratio with respect to tetraalkoxysilane) is too small, the surface treatment layer formed by the resulting composition sufficiently exhibits surface treatment effects such as non-adhesiveness. I can't.
On the other hand, when the content ratio of tetraalkoxytitanium (relative ratio with respect to tetraalkoxysilane) is excessive, the obtained composition is cured in a short time, and workability such as applicability is lowered.

(4) Silane coupling agent:
The silane coupling agent constituting the composition of the present invention is represented by the formula (3): Si (OR ⁶ ) _m R ⁷ _3-m — (CH ₂ ) _n —R ⁸ .
In the above formula (3) showing a silane coupling agent, R ⁶ represents an alkyl group or an alkoxyalkyl group, R ⁷ represents an alkyl group, m is an integer of 1 to 3, preferably 3, and n is 0 An integer of -5, preferably an integer of 0-3. R ⁸ represents an organic functional group having reactivity with the polymer main chain of rubber.
In the above formula (3), the group represented by Si (OR ⁶ ) _m R ⁷ _3-m — has at least one, preferably three hydrolyzable groups (—OR ⁶ ). Thereby, the silane coupling agent represented by the above formula (3) is tetraalkoxysilane having ^four alkoxy groups (—OR ⁴ ), tetraalkoxy titanium having four alkoxy groups (—OR ⁵ ), and It can react with any of the specific fluorine-containing compounds having a plurality of hydrolyzable groups (—OR ¹ ).
Here, the group represented by Si (OR ⁶ ) _m R ⁷ _3-m — is preferably a trialkoxysilyl group such as a trimethoxysilyl group or a triethoxysilyl group.

Examples of the organic functional group (-R ⁸ ) having reactivity with the polymer main chain of rubber include an amino group, a mercapto group, a vinyl group, a (meth) acryloyloxy group, an epoxy group, and a ureido group. it can. Among these, preferred are a mercapto group having reactivity with a polymer main chain of a rubber having an unsaturated bond, and a vinyl group having reactivity with a polymer main chain of a rubber having no unsaturated bond. be able to.
Thus, by selecting the reactive organic functional group (—R ⁸ ) according to the type of rubber (such as the presence or absence of an unsaturated bond in the polymer main chain), the same type as the specific fluorine-containing compound This compound can be used for various rubbers.

On the surface of the rubber to be treated, a specific fluorine-containing compound (—OR ¹ ), tetraalkoxysilane (—OR ⁴ ), tetraalkoxytitanium (—OR ⁵ ), and a silane coupling agent (—OR ⁶⁾ ) Is reacted (hydrolysis / condensation reaction) to form a surface treatment layer made of a hybrid compound (a compound containing a fluorine atom and having a SiO ₂ —TiO ₂ cross-linked structure).
Thus, in the structure of the hybrid compound constituting the surface treatment layer or the formation process (hydrolysis / condensation reaction process), a reactive organic functional group (—R ⁸ ) derived from the silane coupling agent is present. When introduced, this organic functional group (—R ⁸ ) reacts with the polymer main chain of the rubber near the surface of the object to be treated. Thereby, the surface treatment layer (hybrid compound) to be formed is chemically bonded to the polymer main chain of the rubber via the silane coupling agent.

Thus, since a chemical bond is formed between the surface treatment layer made of the hybrid compound and the polymer main chain of the rubber via the silane coupling agent, the surface treatment layer is made of organic matter. It is possible to firmly adhere to a certain rubber (object to be processed).
Therefore, the surface treatment layer is not detached in the use environment, and the imparted surface characteristics are stably expressed.

In the composition of the present invention, the content of the silane coupling agent is preferably 0.01 to 10 times (mass), more preferably 0.05 to 5 times the content of the specific fluorine-containing compound. Particularly preferably, it is 0.1 to 5 times.
When the content ratio of the silane coupling agent (relative ratio with respect to a specific fluorine-containing compound) is too small, the surface treatment layer formed by the resulting composition has sufficient adhesion to the rubber (solvent resistance It does not have the property. On the other hand, if this ratio is excessive, it tends to be difficult to impart the desired treatment effect to the rubber surface.

(5) Solvent:
The solvent constituting the composition of the present invention can be selected from those capable of dissolving any of the specific fluorine-containing compound, tetraalkoxysilane, tetraalkoxytitanium and silane coupling agent. Examples of the organic solvent include hexane, methanol, ethanol, tetrahydrofuran, dichloromethane, chloroform, benzene, ethyl acetate, dimethyl sulfoxide (DMSO), N, N-dimethylformamide (DMF), toluene, and acetone. Of these, hexane, methanol, ethanol, dichloromethane and acetone are preferred.

(6) Optional ingredients:
The composition of the present invention may contain various optional components in addition to the essential components as long as the effect is not impaired.
A viewpoint that promotes the formation of a crosslinked structure in a hybrid compound by efficiently performing a reaction (hydrolysis / condensation reaction) of a specific fluorine-containing compound, tetraalkoxysilane, tetraalkoxytitanium, and a silane coupling agent. Therefore, the composition of the present invention is preferably acidic (pH is 6 or less, particularly 2 to 5).

  The acid contained to make the composition of the present invention acidic may be an inorganic acid or an organic acid. Here, examples of the inorganic acid include hydrochloric acid, nitric acid, sulfuric acid and the like, and hydrochloric acid is preferable. Examples of the organic acid include formic acid, acetic acid, propionic acid, butanoic acid and pentanoic acid, and acetic acid is preferred.

(7) Manufacturing method:
The composition of the present invention can be easily produced by dissolving a specific fluorine-containing compound, tetraalkoxysilane, tetraalkoxytitanium, a silane coupling agent, and optional components in a solvent.
In addition, when the obtained composition is left still for a long time at room temperature, there exists a possibility that the condensate of a structural component (especially tetraalkoxysilane and tetraalkoxytitanium) may be formed and a precipitate may be produced. For this reason, it is preferable to use the composition of the present invention within 24 hours after production, and it is important to homogenize the composition by sufficiently stirring (for example, 1 to 6 hours) before use. is there. Moreover, you may heat to 60-70 degreeC as needed.

(8) Rubber (object to be treated):
The composition of the present invention is used for surface treatment of rubber (vulcanized rubber and unvulcanized rubber), and has various surface characteristics such as non-adhesiveness, lubricity, water repellency on the surface of the rubber. Oil repellency, antifouling property, antibacterial property, physiological activity and the like can be imparted.

  Here, as rubber (raw rubber) to be surface-treated with the composition of the present invention, natural rubber (NR), isoprene rubber (IR), butadiene rubber (BR), chloroprene rubber (CR), butyl rubber (IIR), Styrene butadiene rubber (SBR), nitrile rubber (NBR), ethylene propylene rubber (EPM, EPDM), acrylic rubber (ACM, ANM), epichlorohydrin rubber (CO, ECO), silicone rubber (VMQ, FVMQ), urethane rubber (AU, EU), fluorine rubber (FKM, FEPM) and the like can be exemplified, and among these, particularly excellent treatment effects can be imparted to nitrile rubber.

<Rubber surface treatment method>
The treatment method of the present invention comprises a step of applying the composition of the present invention to the rubber surface (hereinafter referred to as “application step”) and a step of heating the coating film of the composition (hereinafter referred to as “heating step”). Including.

In the coating step, the method for coating the rubber surface of the composition of the present invention is particularly limited, such as a dipping method in which rubber (molded article) is dipped in the composition, a method using a coating means such as a brush or a roller. It is not something.
In addition, after completion | finish of this application | coating process, in order to remove a solvent from the coating film formed on the surface of rubber | gum, it is preferable to perform a drying process. The drying condition varies depending on the type and content ratio of the solvent constituting the composition, but is, for example, 1 minute to 24 hours at room temperature, and preferably 3 minutes to 1 hour.
In the heating step, the method for heating the coating film is not particularly limited, such as heating with an oven or heating with a hot press. The heating condition is, for example, 50 to 150 ° C. for 5 minutes to 24 hours, and preferably 80 to 100 ° C. for 10 to 120 minutes.

By heating the coating film (coating film of the composition of the present invention) applied to the surface of the rubber to be treated, (i) a specific fluorine-containing compound (—OR ¹ ) and tetraalkoxysilane (— OR ⁴ ), tetraalkoxy titanium (—OR ⁵ ), and a silane coupling agent (—OR ⁶ ) undergo a reaction (formation reaction of a crosslinked structure by hydrolysis and condensation), and (ii) silane coupling The reaction between the reactive organic functional group (—R ⁸ ) of the agent and the polymer main chain of the rubber proceeds.
Thereby, (i) a chemical bond is formed between the surface treatment layer (hybrid compound) to be formed and the silane coupling agent, and (ii) between the silane coupling agent and the polymer main chain of the rubber. As a result, a surface treatment layer having excellent adhesion to rubber is formed.

Excellent surface properties (eg, non-adhesiveness, lubricity, abrasion resistance, water and oil repellency) are imparted to the surface of the rubber by the fluorine atoms and the crosslinked structure that constitute this surface treatment layer (hybrid compound). Is done. In particular, the surface treatment layer having a crosslinked structure (SiO ₂ —TiO ₂ -based crosslinked structure) containing a Ti—O bond derived from tetraalkoxytitanium is a surface treated layer (fluorine-containing crosslinked polymer) having an SiO ₂ -based crosslinked structure. Compared with a surface treatment layer made of siloxane, the effect of imparting non-adhesiveness (reducing effect of adhesive force) is remarkably excellent.

In addition, since the surface treatment layer is firmly adhered to the rubber to be treated, the surface treatment layer is not detached in the environment where the rubber product is used, and is applied to the surface. The characteristic is stably expressed.
Moreover, the surface treatment layer (hybrid compound) is excellent in thermal stability and chemical stability, and various organic solvents that are good solvents for the specific fluorine-containing compound constituting the surface treatment layer [for example, methanol, ethanol, tetrahydrofuran , Dichloromethane, chloroform, benzene, ethyl acetate, dimethyl sulfoxide (DMSO), N, N-dimethylformamide (DMF), toluene, acetone). As a result, even when an organic solvent is brought into contact with the rubber product (surface treatment layer) surface-treated with the composition of the present invention, a part of the hybrid compound does not elute, and the surface characteristics imparted thereby are substantial. Will not be damaged.
Thus, the rubber product surface-treated with the composition (treatment method) of the present invention (rubber product in which the surface treatment layer made of a hybrid compound is firmly adhered) was surface-treated with a specific fluorine-containing compound. Compared to rubber products (rubber products having a surface treatment layer made of a specific fluorine-containing compound) and the like, the solvent resistance is significantly superior.

  In addition, since the surface treatment layer made of a hybrid compound is superior in thermal stability to the specific fluorine-containing compound constituting the hybrid compound, a rubber product provided with the surface treatment layer made of the hybrid compound has a certain heat resistance. Can be used for applications that require.

<Relief valve manufacturing method>
The relief valve obtained by the manufacturing method of the present invention is a low-pressure relief valve having a valve body having an O-ring that comes in contact with and separates (contacts / separates) from a valve seat.

FIG. 1 is a schematic cross-sectional view showing an example of such a relief valve. FIG. 1 shows a state when the valve is closed.
In FIG. 1, 10 is a housing, 20 is a valve seat, 30 is a valve body, 40 is a spring, and 50 is a spring compression means.
The relief valve of this example is attached to a pressurized fluid pipe (not shown), and when the pressure in the pipe (primary side pressure) exceeds a set pressure, the valve body 30 to the valve body 30. Is separated (opened) and operates to release the pressurized fluid to the low pressure side (secondary side).

  The housing 10 is made of a metal such as aluminum, and a valve seat 20 (fixed portion) is formed in a part of the housing 10 and has a space for accommodating the valve body 30, the spring 40, and the compression means 50.

The valve body 30 accommodated in the housing 10 is a movable portion of the valve, and includes an O-ring 31 and a guide portion 32.
The O-ring 31 constituting the valve body 30 contacts the valve seat 20 when the valve is closed, and is separated from the valve seat 20 when the valve is opened. The O-ring 31 ensures airtightness (sealability) when the valve is closed.
The guide portion 32 constituting the valve body 30 holds the O-ring 31 and transmits the urging force of the spring 40 to the O-ring 31. A flow path 33 for pressurized fluid is formed in the guide portion 32 by a notch.
The dimensions of the O-ring 31 constituting the "low pressure" relief valve are: wire diameter 1.0 to 5.0 mm, inner diameter 0.5 to 4.0 mm, outer diameter (inner diameter + wire diameter x 2) 2.5 to 14.0 mm.

One end of the spring 40 accommodated in the housing 10 is in contact with the guide portion 32 of the valve body 30, and the other end is in contact with the spring compression means 50.
The spring 40 urges the valve body 30 (O-ring 31) to press against the valve seat 20.
The spring constant of the spring 40 constituting the “low pressure” relief valve is 0.05 to 1.0 N / mm.

The spring compressing means 50 housed in the housing 10 sandwiches and compresses the spring 40 together with the valve body 30 (guide portion 32), thereby causing the spring 40 to exert a biasing force on the valve body 30. It is.
A screw (outer screw) is formed on the outer peripheral surface 51 of the compression means 50, and the compression means 50 is engaged with the screw (inner screw) formed on the inner peripheral surface 11 of the housing 10. Can be moved in the compression / extension direction of the spring 40, whereby the amount of compression of the spring 40, and hence the biasing force by the spring 40, can be adjusted as appropriate. Reference numeral 52 denotes a pressurized fluid channel provided in the compression means 50.

  In the relief valve shown in FIG. 1, when the pressure in the pipe line (primary side pressure) reaches the set pressure, the valve body 30 (O-ring 31) is separated from the valve seat 20 and opened. Thereby, the pressurized fluid in the pipe enters the housing 10 from the valve seat 20, and the flow path 33 formed in the guide portion 32, the internal space of the spring 40, and the flow path 52 formed in the compression means 50. And is released to the low pressure side (secondary side).

The operating pressure (pressure when the valve is opened) of the relief valve obtained by the production method of the present invention is 100 KPa or less, preferably 50 KPa or less, more preferably 40 KPa or less.
A relief valve for low pressure having an operating pressure of 100 KPa or less is susceptible to the adhesion between the valve element (O-ring) and the valve seat because the urging force of the spring is small.
Therefore, the low adhesion between the valve body (O-ring) and the valve seat achieved by the present invention is important in such a low-pressure relief valve.

The method for producing a relief valve of the present invention includes a step of applying the composition of the present invention to an O-ring, a step of surface-treating the O-ring by heating a coating film of the composition, and the surface-treated Mounting an O-ring as a component of the valve body.
That is, the manufacturing method of the relief valve of the present invention is characterized in that the O-ring treated by the surface treatment method of the present invention is mounted as a component part of the valve body.

The method for applying the composition of the present invention is not particularly limited, such as a dipping method in which an O-ring is immersed in the composition, a method using an application means such as a brush or a roller.
In addition, after apply | coating a composition, it is preferable to perform a drying process in order to remove a solvent from the coating film formed in the surface of O-ring. The drying condition varies depending on the type and content ratio of the solvent constituting the composition, but is, for example, 1 minute to 24 hours at room temperature, and preferably 3 minutes to 1 hour.
The method for heating the coating film is not particularly limited, such as heating with an oven or heating with a hot press. The heating condition is, for example, 50 to 150 ° C. for 5 minutes to 24 hours, preferably 80 to 120 ° C. for 5 to 120 minutes.

By heating the coating applied to the surface of the O-ring (coating by the composition of the present invention), (i) reaction of tetraalkoxysilane, tetraalkoxytitanium, and silane coupling agent (hydrolysis / The reaction of (ii) the reactive organic functional group possessed by the silane coupling agent and the polymer main chain of the rubber that constitutes the O-ring proceeds.
As a result, a chemical bond is formed between (i) the surface treatment layer (hybrid compound) to be formed and the silane coupling agent, and (ii) between the silane coupling agent and the polymer main chain of the rubber. As a result, a surface treatment layer excellent in adhesion (durability and toughness as a coating) to the rubber constituting the O-ring is formed.

Since the relief valve obtained by the production method of the present invention has extremely low adhesiveness of the O-ring constituting it, the operating pressure after being left is set even after being left for a long time in the closed state. There is no significant change from the pressure (operating pressure before leaving).
Moreover, according to the relief valve obtained by the production method of the present invention, the surface treatment layer formed on the O-ring can be obtained even if the valve opening / closing operation including leaving the valve in a closed state for a long time is repeated many times. There is no peeling, and the performance (non-adhesiveness) of the surface treatment layer can be stably expressed over a long period of time, and the operating pressure does not change greatly from the set pressure.

  Examples of the present invention will be described below, but the present invention is not limited thereto.

[Production Example A (Production of rubber plate)]
Nitrile rubber “JSR N240S” (manufactured by JSR Corporation) 100 parts by mass, anti-aging agent “NOCRACK CD” 1.5 parts by mass, stearic acid “ADEKA FATTY ACID SA-300” 1.5 parts by mass, oxidation 5 parts by weight of zinc, 70 parts by weight of carbon black “Thermax MT”, 10 parts by weight of calcium carbonate “Hakuenka CC” (manufactured by Shiroishi Kogyo Co., Ltd.), 30 parts by weight of dioctyl phthalate (DOP), and 0 sulfur .3 parts by mass, 1.5 parts by mass of vulcanization accelerator “Noxeller TT” (Ouchi Shinsei Chemical Co., Ltd.) and vulcanization accelerator “Noxeller CZ-G” (Ouchi Shinsei Chemical Co., Ltd.) ) 1.5 parts by mass were kneaded with an 8-inch roll to prepare an unvulcanized rubber made of a nitrile rubber composition. Next, this unvulcanized rubber was heat-treated (150 ° C. × 20 minutes) using a hot press to prepare a rubber plate (base material) made of nitrile rubber (vulcanized rubber) with a thickness of 2.0 mm. .

<Example 1A>
(1) Preparation of surface treatment composition:
According to the formulation shown in Table 1 below, 0.004 g of the specific fluorine-containing compound represented by the above formula (4), 0.40 g of tetraethoxysilane (TEOS), and 0.004 g of tetraethoxytitanium [Ti (OEt) ₄ ] And a silane coupling agent “A-189” (manufactured by Nihon Unicar Co., Ltd.) represented by the formula: Si (OCH ₃ ) ₃ — (CH ₂ ) ₃ —SH, and hydrochloric acid (0.1N) 0 0.05 g of acetone is added to 9.5 g of acetone, and the system is stirred at room temperature for 1 hour, whereby the composition of the present invention (specific fluorine-containing compound concentration = 0.04 mass%, TEOS concentration = 4. 0% by mass, tetraethoxytitanium concentration = 0.04% by mass, silane coupling agent concentration = 0.1% by mass).

(2) Rubber plate surface treatment:
By immersing the rubber plate obtained in Preparation Example A for 3 minutes at room temperature in the composition of the present invention obtained by the above (1) (composition immediately after completion of the stirring operation for 1 hour), The composition was applied to the entire surface of the rubber plate. Next, the rubber plate is allowed to stand at room temperature for 10 minutes to dry the coating film, and then subjected to a heat treatment in an oven at 100 ° C. for 60 minutes, whereby a surface treatment layer (comprising a hybrid compound) of the composition of the present invention. A rubber plate having a surface treatment layer was obtained.

<Example 2A>
According to the formulation shown in Table 1 below, the composition of the present invention (tetraethoxytitanium concentration = 0.08% by mass) was the same as Example 1A (1) except that the amount of tetraethoxytitanium used was changed to 0.008 g. And a rubber plate having a surface treatment layer formed of the composition of the present invention was obtained in the same manner as in Example 1A (2) except that the obtained composition was used.

<Example 3A>
According to the formulation shown in Table 1 below, the composition of the present invention (tetraethoxytitanium concentration = 0.12% by mass) was the same as Example 1A (1) except that the amount of tetraethoxytitanium used was changed to 0.012 g. And a rubber plate having a surface treatment layer formed of the composition of the present invention was obtained in the same manner as in Example 1A (2) except that the obtained composition was used.

<Example 4A>
According to the formulation shown in Table 1 below, the composition of the present invention (tetraethoxy titanium concentration = 0.20% by mass) was the same as Example 1A (1) except that the amount of tetraethoxy titanium used was changed to 0.020 g. And a rubber plate having a surface treatment layer formed of the composition of the present invention was obtained in the same manner as in Example 1A (2) except that the obtained composition was used.

<Example 5A>
According to the formulation shown in Table 1 below, the composition of the present invention (tetraethoxytitanium concentration = 0.28% by mass) was the same as Example 1A (1) except that the amount of tetraethoxytitanium used was changed to 0.028 g. And a rubber plate having a surface treatment layer formed of the composition of the present invention was obtained in the same manner as in Example 1A (2) except that the obtained composition was used.

<Example 6A>
According to the formulation shown in Table 1 below, the composition of the present invention (tetraethoxy titanium concentration = 0.40 mass%) was carried out in the same manner as in Example 1A (1) except that the amount of tetraethoxy titanium used was changed to 0.040 g. And a rubber plate having a surface treatment layer formed of the composition of the present invention was obtained in the same manner as in Example 1A (2) except that the obtained composition was used.

<Example 7A>
According to the formulation shown in Table 1 below, the amount of tetraethoxytitanium was changed to 0.008 g, and the amount of silane coupling agent was changed to 0.02 g. Example 1A (2) except that the composition of the invention (tetraethoxytitanium concentration = 0.08 mass%, silane coupling agent concentration = 0.2 mass%) was prepared, and the resulting composition was used. Similarly, a rubber plate having a surface treatment layer formed of the composition of the present invention was obtained.

<Example 8A>
In accordance with the formulation shown in Table 1 below, instead of the specific fluorine-containing compound represented by the above formula (4), the specific fluorine-containing compound represented by the above formula (6) (provided that xb = 1 to 10, yb is 1 -10) The composition of the present invention (tetraethoxytitanium concentration = 0.08) in the same manner as in Example 1A (1) except that 0.004 g was used and the amount of tetraethoxytitanium was changed to 0.008 g. Mass%) was prepared, and a rubber plate having a surface treatment layer formed of the composition of the present invention was obtained in the same manner as in Example 1A (2) except that the obtained composition was used.

  The rubber plates obtained in Example 1A to Example 8A were all excellent in water and oil repellency.

<Comparative Example 1A>
The rubber plate (base material) obtained in Preparation Example A was heat-treated in an oven at 100 ° C. for 60 minutes to obtain a comparative rubber plate on which no surface treatment layer was formed.

<Comparative Example 2A>
According to the formulation shown in Table 1 below, a comparative composition was prepared in the same manner as in Example 1A (1) except that tetraethoxytitanium was not used, and it was carried out except that the obtained composition was used. In the same manner as in Example 1A (2), a rubber plate having a surface treatment layer formed of a comparative composition was obtained.

<Comparative Example 3A>
A composition for comparison was prepared in the same manner as in Example 1A (1) except that no silane coupling agent was used in accordance with the formulation shown in Table 1 below, except that the obtained composition was used. In the same manner as in Example 1A (2), a rubber plate having a surface treatment layer formed of a comparative composition was obtained.

<Reference Example 1>
According to the formulation shown in Table 1 below, the composition of the present invention (tetraethoxy titanium concentration = 0.80 mass%) was carried out in the same manner as in Example 1A (1) except that the amount of tetraethoxy titanium used was changed to 0.080 g. ) Was prepared. In the obtained composition, since the cloudiness considered to be due to the progress of the condensation reaction was observed, the same surface treatment as in Example 1A (2) was not performed. When the concentration of tetraethoxytitanium is high, it seems necessary to prepare and use the composition under strict temperature and humidity control.

<Evaluation of non-stickiness>
About each of the rubber plate obtained by said Example 1A-Example 8A and comparative example 1A-comparative example 3A, using a tacking tester "TAC-II" (made by Resuka Co., Ltd.), metal (stainless steel) The non-adhesiveness of the surface was evaluated by measuring the adhesive strength against the surface. The results are also shown in Table 1.
Here, the measurement conditions are as follows.

〔Measurement condition〕
(1) Probe material: SUS304
(2) Probe shape: cylindrical shape with a diameter of 5.1 mm (3) Approach speed: 5 mm / min
(4) Applied pressure: 100 gf
(5) Pressurization time: 3 seconds (6) Separation (separation) speed: 600 mm / min
(7) Measurement temperature: room temperature

  Further, each of the rubber plates obtained in Examples 1A to 8A above was subjected to contact treatment with each solvent shown in Table 1 below (Soxhlet extraction, extraction time = 12 hours), and then the same as above. Then, the non-adhesiveness of the surface after contact with the solvent was evaluated by measuring the adhesive force again. The results are also shown in Table 1.

[Production Example B (Production of O-ring)]
In the same manner as in Production Example A, a nitrile rubber composition (unvulcanized rubber) was prepared, and this unvulcanized rubber was subjected to heat treatment (150 ° C. × 20 minutes) using a hot press to obtain an O-ring (wire). Diameter = 1.42 mm, inner diameter = 1.53 mm, outer diameter = 4.37 mm).

<Example 1B>
(1) Preparation of surface treatment composition:
In accordance with the formulation shown in Table 2 below, 0.004 g of the specific fluorine-containing compound represented by the above formula (4), 0.40 g of tetraethoxysilane (TEOS), and 0.004 g of tetraethoxytitanium [Ti (OEt) ₄ ] And 0.01 g of silane coupling agent “A-189” (manufactured by Nippon Unicar Co., Ltd.) and 0.05 g of hydrochloric acid (0.1N) were added to 9.5 g of acetone, and the system was cooled to room temperature. The composition of the present invention (having the same composition as that obtained in Example 1A) was prepared by stirring for 1 hour.

(2) O-ring surface treatment:
By immersing the O-ring obtained in Preparation Example B at room temperature for 3 minutes in the composition of the present invention obtained by the above (1) (composition immediately after completion of the stirring operation for 1 hour), for 3 minutes. The composition of the present invention was applied to the surface of the O-ring. Next, the O-ring is allowed to stand at room temperature for 10 minutes to dry the coating film, and then subjected to surface treatment with the composition of the present invention by heat treatment in an oven at 100 ° C. for 60 minutes. An O-ring formed with a surface treatment layer was produced.

(3) Manufacture of relief valves:
A structure as shown in FIG. 1 is obtained by mounting the O-ring surface-treated according to (2) above on the guide portion to form a valve body, and housing the valve body, the spring, and the compression means of the spring in the housing. A relief valve for low pressure having
In this relief valve, the pressure receiving area (A) of the valve body is approximately 0.07 cm ² , the spring constant of the spring is approximately 0.16 N / mm, the urging force (F) is 0.14 to 0.70 N, and the operating pressure is 20 ~ 100 KPa.

<Example 2B>
According to the formulation shown in Table 2 below, the composition of the present invention (same as that obtained in Example 2A) was the same as Example 1B (1) except that the amount of tetraethoxytitanium used was changed to 0.008 g. O-ring surface-treated with the composition of the present invention was produced in the same manner as in Example 1B (2) except that the composition was prepared and the obtained composition was used. A low-pressure relief valve was produced in the same manner as in Example 1B (3) except that a ring was attached to the guide portion to form a valve body.

<Example 3B>
According to the formulation shown in Table 2 below, the composition of the present invention (same as that obtained in Example 3A) was the same as Example 1B (1) except that the amount of tetraethoxytitanium was changed to 0.012 g. O-ring surface-treated with the composition of the present invention was produced in the same manner as in Example 1B (2) except that the composition was prepared and the obtained composition was used. A low-pressure relief valve was produced in the same manner as in Example 1B (3) except that a ring was attached to the guide portion to form a valve body.

<Example 4B>
According to the formulation shown in Table 2 below, the composition of the present invention (same as that obtained in Example 4A) was obtained in the same manner as Example 1B (1) except that the amount of tetraethoxytitanium was changed to 0.020 g. O-ring surface-treated with the composition of the present invention was produced in the same manner as in Example 1B (2) except that the composition was prepared and the obtained composition was used. A low-pressure relief valve was produced in the same manner as in Example 1B (3) except that a ring was attached to the guide portion to form a valve body.

<Example 5B>
According to the formulation shown in Table 2 below, the composition of the present invention (same as that obtained in Example 5A) was the same as Example 1B (1) except that the amount of tetraethoxytitanium was changed to 0.028 g. O-ring surface-treated with the composition of the present invention was produced in the same manner as in Example 1B (2) except that the composition was prepared and the obtained composition was used. A low-pressure relief valve was produced in the same manner as in Example 1B (3) except that a ring was attached to the guide portion to form a valve body.

<Example 6B>
According to the formulation shown in Table 2 below, the composition of the present invention (same as that obtained in Example 6A) was the same as Example 1B (1) except that the amount of tetraethoxytitanium used was changed to 0.040 g. O-ring surface-treated with the composition of the present invention was produced in the same manner as in Example 1B (2) except that the composition was prepared and the obtained composition was used. A low-pressure relief valve was produced in the same manner as in Example 1B (3) except that a ring was attached to the guide portion to form a valve body.

<Example 7B>
According to the formulation shown in Table 2 below, the amount of tetraethoxytitanium used was changed to 0.008 g, and the amount of silane coupling agent used was changed to 0.02 g. The composition of the present invention was prepared in the same manner as in Example 1B (2) except that the composition of the invention (with the same composition as that obtained in Example 7A) was prepared and the resulting composition was used. A relief valve for low pressure was produced in the same manner as in Example 1B (3) except that the surface-treated O-ring was produced and the obtained O-ring was attached to the guide portion to obtain a valve body.

<Example 8B>
In accordance with the formulation shown in Table 2 below, instead of the specific fluorine-containing compound represented by the above formula (4), the specific fluorine-containing compound represented by the above formula (6) (provided that xb = 1 to 10, yb is 1 10) 0.004 g was used, and the composition of the present invention (obtained in Example 8A) was the same as Example 1B (1) except that the amount of tetraethoxytitanium used was changed to 0.008 g. And an O-ring surface-treated with the composition of the present invention was obtained in the same manner as in Example 1B (2) except that the obtained composition was used. A relief valve for low pressure was manufactured in the same manner as in Example 1B (3) except that the O-ring was attached to the guide portion to obtain a valve body.

<Comparative Example 1B>
A relief valve for low pressure was produced in the same manner as in Example 1B (3) except that the O-ring obtained in Production Example B was attached to the guide portion to obtain a valve body.

<Comparative Example 2B>
In accordance with the formulation shown in Table 2 below, a comparative composition (with the same composition as that obtained in Comparative Example 2A) was prepared in the same manner as in Example 1B (1) except that tetraethoxytitanium was not used. An O-ring surface-treated with a comparative composition was produced in the same manner as in Example 1B (2) except that the prepared and obtained composition was used, and the obtained O-ring was used as a guide part. A low-pressure relief valve was produced in the same manner as in Example 1B (3) except that the valve body was mounted.

<Comparative Example 3B>
A composition for comparison (same composition as that obtained in Comparative Example 3A) in the same manner as Example 1B (1) except that no silane coupling agent was used according to the formulation shown in Table 2 below. In the same manner as in Example 1B (2) except that the obtained composition was used, an O-ring surface-treated with a comparative composition was produced, and the obtained O-ring was used as a guide part. A relief valve for low pressure was manufactured in the same manner as in Example 1B (3) except that the valve body was attached to the valve body.

<Relief valve evaluation experiment (1)>
For each of the relief valves obtained in Example 1B to Example 8B and Comparative Example 1B to Comparative Example 3B, the rate of increase in operating pressure was measured by leaving the valve closed for a certain period of time. Specifically, by attaching a relief valve to a pipeline equipped with air pressure adjusting means (pressure reducing valve), setting the operating pressure in the range of 30 to 35 KPa, and then setting the air pressure in the pipeline to 0 KPa Leave the relief valve closed for 1 hour, then increase the air pressure in the pipeline and measure the operating pressure again. The ratio of the operating pressure after leaving to the operating pressure before setting (set pressure) (Increase rate) was calculated. The results are also shown in Table 2 below. The operating pressure of the relief valve was set by adjusting the compression amount of the spring with the compression means.

<Relief valve evaluation experiment (2)>
For each of the relief valves obtained in Example 1B to Example 8B and Comparative Example 1B to Comparative Example 3B, a relief valve is attached to a pipe line equipped with an air pressure adjusting means (pressure reducing valve), and the operating pressure is 30. After setting in the range of ~ 35 KPa, the valve closed state (1 hour) and the valve open state (10 seconds) are set as one cycle, and after 300 cycles of opening and closing operations, the operating pressure is measured again and the operation before leaving The ratio (increase rate) of the operating pressure after repeated opening and closing operations to the pressure (set pressure) was determined. The results are also shown in Table 2 below.

  The surface treatment composition and the rubber surface treatment method of the present invention are suitably used for rubber products that require non-tackiness and the like, for example, rubber products that come in contact with (separate from / separate from) dissimilar members such as metals. be able to. Examples of such rubber products include valves, packings, sealing materials, and the like.

  The relief valve obtained by the production method of the present invention is suitably used as a pressure adjusting valve (relief valve) attached to an air pressure circuit in various fields.

It is a schematic sectional drawing which shows an example of the relief valve obtained by the manufacturing method of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Housing 20 Valve seat 30 Valve body 31 O-ring 32 Guide part 33 Flow path of pressurized fluid 40 Spring 50 Compression means 51 Outer peripheral surface 52 Flow path of pressurized fluid

Claims (10)

A composition for treating the surface of rubber,
A fluorine-containing compound represented by the following formula (F1);
A tetraalkoxysilane represented by the formula (1): Si (OR ⁴ ) ₄ (wherein R ⁴ represents an alkyl group having 1 to 4 carbon atoms);
Tetraalkoxytitanium represented by formula (2): Ti (OR ⁵ ) ₄ (wherein R ⁵ represents an alkyl group having 2 to 4 carbon atoms);
Equation ^{(3): Si (OR 6} ) m R 7 3-m - (CH 2) n -R 8 ( wherein, R ⁶ represents an alkyl group or an alkoxyalkyl group, R ⁷ represents an alkyl group, m Is an integer of 1 to 3, n is an integer of 0 to 5. R ⁸ represents an organic functional group having reactivity with the polymer main chain of the rubber. When,
The surface treatment composition containing the solvent which melt | dissolves these.

(Wherein R _F represents a group containing a fluoroalkyl group, R ¹ represents an alkyl group or an alkoxyalkyl group, and R ² and R ³ represent the same or different hydrogen atoms or monovalent organic groups. X is an integer from 1 to 100, and y is an integer from 0 to 100.) A composition for treating the surface of rubber,
A fluorine-containing compound represented by the following formula (F2);
A tetraalkoxysilane represented by the formula (1): Si (OR ⁴ ) ₄ (wherein R ⁴ represents an alkyl group having 1 to 4 carbon atoms);
Tetraalkoxytitanium represented by formula (2): Ti (OR ⁵ ) ₄ (wherein R ⁵ represents an alkyl group having 2 to 4 carbon atoms);
Equation ^{(3): Si (OR 6} ) m R 7 3-m - (CH 2) n -R 8 ( wherein, R ⁶ represents an alkyl group or an alkoxyalkyl group, R ⁷ represents an alkyl group, m Is an integer of 1 to 3, n is an integer of 0 to 5. R ⁸ represents an organic functional group having reactivity with the polymer main chain of the rubber. When,
The surface treatment composition containing the solvent which melt | dissolves these.

(In the formula, R _F represents a group containing a fluoroalkyl group, R ¹ represents an alkyl group or an alkoxyalkyl group, and x is an integer of 1 to 100.) In the formula (F1) or the formula (F2) showing the fluorine-containing compound, the group containing a fluoroalkyl group represented by R _F is -CF ₃ , -C ₂ F ₅ , -C ₃ F ₇ , —C ₆ F ₁₃ , —C ₇ F ₁₅ or —CF (CF ₃ ) [OCF ₂ CF (CF ₃ )] _p OC ₃ F ₇ (wherein p is 0, 1 or 2). The surface treatment composition according to claim 1 or 2.   The surface treatment composition according to claim 1, wherein the tetraalkoxysilane is tetramethoxysilane or tetraethoxysilane.   5. The surface treatment composition according to claim 1, wherein the tetraalkoxytitanium is at least one selected from tetraethoxytitanium, tetra-iso-propoxytitanium, and tetra-n-butoxytitanium.   The surface treatment composition according to any one of claims 1 to 5, comprising an acid.   The surface treatment composition according to claim 2, comprising a fluorine-containing compound represented by the formula (F2), tetraethoxysilane, tetraethoxytitanium, a silane coupling agent, an acid, and an organic solvent.   A rubber surface treatment method comprising: a step of applying the surface treatment composition according to any one of claims 1 to 7 to a rubber surface; and a step of heating a coating film of the surface treatment composition.   The rubber surface treatment method according to claim 8, wherein the surface of the nitrile rubber is treated. A method of manufacturing a relief valve for low pressure having a valve body with an O-ring contacting and separating from a valve seat and operating at a pressure of 100 KPa or less,
A step of applying the surface treatment composition according to any one of claims 1 to 7 to an O-ring, a step of surface-treating the O-ring by heating a coating film of the surface treatment composition, and a surface Mounting the processed O-ring as a component of the valve body.

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