JP2001123117A - Surface-treating agent - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a surface-treating agent capable of being applied to the surface treatment of an elastic body such as a vulcanized rubber molded product and a resin elastomer molded product, and excellent in coatability, friction and abrasion characteristics, nontacky properties, sealing properties or the like. SOLUTION: This surface treating agent contains a silane coupling agent, a silicone polymer having about 100,000-1,000,000 average molecular weight, and an organic solvent-soluble cellulose derivative.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a surface treatment agent. More specifically, the present invention relates to a surface treatment agent effectively used for surface treatment of elastic bodies such as vulcanized rubber molded articles and resin elastic body molded articles.

[0002]

2. Description of the Related Art The following problems are generally observed in elastic bodies such as vulcanized rubber molded articles and resin elastic body molded articles. -When the elastic bodies are overlapped with each other, they stick together and there is a problem in work.-When the elastic parts are incorporated into the device etc., the sticking occurs between the elastic bodies and the contact surface of the mating parts, especially the parts feeder etc. In the automatic mounting by, the elastic parts tend to stick to each other due to the adhesion of the elastic parts.Since the surface of the elastic parts does not slide well, the sliding resistance and operating resistance increase after assembly and the operation stops. Or
The problem of loud vibration and slipping noise occurs.
Adhesion or sticking occurs with resin, glass, or other mating materials, causes problems such as increased operating resistance of the equipment, or makes detachment difficult during maintenance replacement.Grease or lubrication of elastic parts Lubricants such as oils may be applied and used.However, these lubricants are oily and are easily released by contact. Immersed in oil, fuel oil, solvent, etc., causes oil to be released from the coating film, resulting in reduced slipperiness and non-adhesive performance.

[0003] To cope with such various problems, for example, a method of applying a treating agent composed of wax, silicone oil and a cellulose derivative (Japanese Patent Publication No. 5-12381) has been proposed.
It is effective for initial adhesion between elastic bodies, but because the coating film only adheres to the elastic body surface and is not chemically bonded to the functional groups on the elastic body surface, it is compressed at high temperature and slid for a long time. The coating film is peeled off by immersion in fuel oil, a solvent, or the like. In particular, there is a problem in that the silicone oil, which is a lubricant, is released from the coating film due to long-time sliding, and the sliding performance and the non-adhesive performance are reduced, and the sustainability of these performances is lacking.

In addition, the coating liquid used in this method contains fine particles of wax, so that the coating thickness is necessarily larger than the particle diameter of the wax, so that the flexibility and sealing properties of the elastic parts are impaired, There is a problem that processing cost becomes high. Furthermore, since the wax is not dissolved in the coating liquid but is dispersed, the sedimentation of the wax and agglomeration of the wax in the coating liquid are liable to occur, causing trouble during coating and appearance of the coating. May be damaged.

On the other hand, molybdenum disulfide, graphite,
A method of applying a paint comprising a silicone rubber powder, a resin powder or the like or a solid lubricant with these (Japanese Patent Laid-Open No. 5-7
No. 7690, No. 9-109703, No. 9-111179,
No. 10-1640), rubber or resin powder is blended, powder may fall off during friction, and the applied thickness is greater than the powder particle size, which impairs the flexibility and sealing properties of the elastic parts. And the processing cost is high.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a surface treating agent applied to the surface treatment of an elastic body such as a vulcanized rubber molded article or a resin elastic body molded article. An object of the present invention is to provide a material having excellent adhesiveness, non-adhesiveness, and sealing properties.

[0007]

SUMMARY OF THE INVENTION The object of the present invention is as follows.
This is achieved by a surface treatment agent containing a silane coupling agent, a silicone polymer having an average molecular weight of about 100,000 to 1,000,000 and an organic solvent-soluble cellulose derivative.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As a silane coupling agent,
General formula X (R ′) _n Si (OR) _3-n OR: lower alkoxyl group or lower acyl group R ′: lower alkyl group X: amino group, vinyl group, epoxy group, mercapto group,
Those having a functional group n: 0 or 1 which reacts with an organic group such as a methacryloxy group and a chloro group are generally used.

Specific examples of such a silane coupling agent include γ- (aminoethyl) aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β-
(Aminoethyl) -γ-aminopropyltrimethoxysilane, γ-anilinopropyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriacetoxysilane, γ-glycidoxypropyltrimethoxysilane, β- ( 3,4-epoxycyclohexyl)
Ethyltrimethoxysilane, γ-mercaptotrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-chloropropyltrimethoxysilane, octadecylmethyl (3-trimethoxysilyl) propylammonium chloride, γ- (2-aminoethyl) Examples include aminopropylmethyldimethoxysilane, N-β- (N-vinylbenzylaminoethyl) -γ-aminopropylmethyldimethoxysilane.hydrochloride, γ-mercaptopropylmethyldimethoxysilane, γ-chloropropylmethyldimethoxysilane, and the like.

In addition to these, vinyl trichlorosilane, methyltrimethoxysilane, methyltriethoxysilane, hexamethyldisilazane, methyltrichlorosilane, dimethyldichlorosilane, trichloromethylsilane and the like are also used.

These silane coupling agents account for about 20% of the total amount of the silicone polymer and the cellulose derivative.
7070% by weight, preferably about 30-60% by weight. If the use ratio is lower than this, the adhesion to the elastic body to be surface-treated is reduced, and as a result, the durability of the sliding performance and the non-adhesive performance is reduced, and the friction and wear characteristics are also reduced. On the other hand, if a higher ratio is used, the flexibility of the cured coating film will be impaired, and the cured coating film will be cracked by compression, bending, tension, etc. Non-adhesive performance will be impaired.

As the silicone polymer, those having an average molecular weight of about 100,000 to 1,000,000, preferably about 300,000 to 600,000 are used. If the average molecular weight is less than this, the low molecular weight silicone bleeds on the surface of the coating film, causing stickiness on the surface of the elastic body and losing the sustainability of the sliding performance upon rubbing. On the other hand, if the average molecular weight is higher than this, it becomes difficult to dissolve in toluene, xylene or various solvents containing these. In the case of a silicone polymer having a high average molecular weight and hardly soluble in these solvents, it can be plasticized using an open roll, a three-roll or the like, and can be made soluble in these solvents.

More specific silicone polymers include dimethyl silicone, methyl vinyl silicone, methyl phenyl vinyl silicone and methyl fluoroalkyl.
(Fluorosilicone) and other rubbery or resinous polymers,
Preferably, silicone rubber is used. Actually, commercially available silicone rubber or a compound containing a filler such as silica, calcium carbonate, titanium oxide or the like is preferably used.

The silicone polymer is used in an amount of about 10 to 60% by weight in the total amount of the silane coupling agent and the cellulose derivative.
%, Preferably about 20-50% by weight. If the use ratio is less than this, the flexibility of the cured coating film will be impaired, and the cured coating film will crack due to compression, bending, tension, etc., reducing the sealability, sliding performance, non-adhesion Performance will be impaired. On the other hand, if used in a higher ratio, the amount of silicone oil (low molecular weight of the silicone polymer) that oozes out on the cured coating film surface increases and stickiness occurs, so that the adhesion to the elastic body is reduced. Become.

Examples of the cellulose derivative soluble in an organic solvent include methyl cellulose, ethyl cellulose, carboxymethyl cellulose, carboxymethyl ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, and ethyl hydroxyethyl cellulose which are soluble in toluene, xylene or a mixed solvent containing these. Used.

These cellulose derivatives comprise about 5% of the total amount of the silane coupling agent and the silicone polymer.
-40% by weight, preferably about 10-30% by weight. If the use ratio is less than this, application unevenness is likely to occur at the time of application to the surface of the elastic body, and the amount of silicone oil (low molecular weight of silicone polymer) oozing out on the surface of the cured coating film increases, causing stickiness, It causes blocking. On the other hand, if it is used at a higher ratio, the flexibility of the cured coating film is impaired, and the cured coating film is cracked by compression, bending, tension or the like, and the sealing property is reduced.

The concentration of the surface treatment solution prepared by dissolving the above components in an organic solvent is adjusted according to the thickness of the coating, the coating method and the like. About application thickness, generally
It is set to about 0.1 to 10 μm, preferably about 0.5 to 5 μm. If the coating thickness is less than this, the surface treatment effect aimed at by the present invention is not sufficiently exhibited, while if the coating thickness is more than this, the rigidity of the elastic body surface increases, and the sealing property and flexibility may be impaired. is there. In addition, as a coating method, any method such as a dipping method, a spray method, a roll coater method, and a flow coater method can be used.

Examples of the elastic body surface-treated with such a surface treating agent according to the present invention include vulcanized molded articles of synthetic rubber or natural rubber such as fluorine rubber, acrylic rubber, silicone rubber, NBR, SBR, EPDM, and the like. A resin elastic body molded article such as a thermoplastic elastomer, a thermoplastic resin, and a thermosetting resin may be used. It is desirable for these elastic bodies to remove stains and the like on the surface of the elastic bodies by washing or the like before the surface treatment. In particular, in the case of a rubber material, since bleeding may be precipitated on the surface of the vulcanized rubber molded product, it is desirable to perform surface treatment after washing and drying with water, a detergent, an organic solvent, and the like.

[0019]

[Function] Of the three components constituting the surface treatment agent of the present invention, the silane coupling agent chemically reacts with the functional group on the surface of the elastic body, and the silicone polymer imparts a sliding property and a non-adhesive property to the elastic body surface. In addition, the cellulose derivative improves coatability and non-stickiness.

By applying a surface treating agent comprising such components to the surface of the elastic body and heating it to about 100 to 250 ° C. as necessary, the crosslinking reaction of the coating film proceeds, and the functional Many chemical bonds such as hydrogen bonds, ionic bonds, and covalent bonds are formed between the base and the coating film, and as a result, the adhesion between the elastic body and the coating film is improved.

[0021]

When the surface of the elastic body is surface-treated with the surface treating agent according to the present invention, the following effects can be obtained. (1) Excellent coating properties of surface treatment agent. (2) The tackiness between the surface-treated vulcanized rubber molded products is reduced, and blocking does not occur. (3) The surface of the surface-treated vulcanized rubber molded product has low friction and low sliding resistance, and is excellent in mounting workability. (4) Since many chemical bonds are formed between the functional group on the surface of the surface-treated vulcanized rubber molded product and the surface treatment agent, the performance such as low friction and low sliding resistance is persistent, Also, abrasion of rubber can be reduced. (5) Adhesion and adhesion to metal are low, and this tendency is maintained even at high temperatures. This is presumably because the formation of the chemical bond exerts durability and non-adhesion at high temperatures of the surface-treated elastic body. (6) Even if the coating thickness is thin, there is no coating unevenness, and processing capable of exhibiting desired performance at low cost is possible. Also,
Since the coating thickness is thin and flexible, the physical properties of the elastic body are not impaired, and particularly in the case of a sealing part, an elastic body having excellent sealing properties can be provided. (7) Slip noise and rubbing noise of elastic parts can be reduced.

The surface treating agent of the present invention having such effects can be used as a sealing material such as an O-ring, a square ring, a D-ring, a V-packing, an oil seal, a gasket, a packing, etc., which are used for preventing leakage of liquid. It can be effectively applied to industrial or consumer rubber or resin products such as dust boots such as joints, various valves, diaphragms, wiper blades, etc., without being limited to their shapes and without impairing their appearance.

[0023]

Next, the present invention will be described by way of examples. In addition, all the parts showing the used amount are parts by weight.

Example 1 Silicone rubber (methyl vinyl silicone raw rubber, average molecular weight: 400,000) 40 parts Ethyl cellulose 20 parts Silane coupling agent 40 parts (vinyltrimethoxysilane-aminopropyltriethoxysilane equimolar mixture) Prepared from toluene 5900 parts The surface treatment agent solution was tested for the following items.

(1) Coatability test The state of the coating when the above surface treatment agent solution was applied to a vulcanized fluoro rubber sheet (100 × 100 × 2 mm) by dipping was visually observed. △: Slight unevenness, but applied over the entire surface, ×: Scratch or unevenness, not applied over the entire surface

(2) Dynamic friction measurement test The above surface treatment agent solution was applied to a vulcanized fluoro rubber sheet (100 × 25 × 2 mm) to a thickness of 1 μm by spraying, and heat-treated at 150 ° C. for 10 minutes. The rubber sheet was tested with a surface tester manufactured by Shinto Kagaku in accordance with ASTM D-1894.
mm chrome steel ball friction element, moving speed: 50mm / min, load 50g
Surface dynamic friction coefficient measured under various test conditions

(3) Static Friction Measurement Test The above surface treatment agent solution was applied to a vulcanized fluoro rubber O-ring (inner diameter 7.8 mm, thickness 1.9 mm; nominal number P8) by spraying to a thickness of about 1 μm, After the heat treatment for 10 minutes, place the surface-treated O-ring on the PTFE processed aluminum plate, tilt the aluminum plate, measure the angle θ at which the O-ring starts to move, and evaluate the static friction coefficient as tan θ

(4) Abrasion test The above surface treatment agent solution was applied to a vulcanized fluoro rubber disk (diameter 63 mm, thickness 2 mm) by spraying to a thickness of about 1 μm,
After heat treatment for 10 minutes, press the metal ring (inner diameter 53 mm, diameter 41 mm) on the surface-treated rubber sheet according to the friction and wear test method (JIS K-7218 A method),
Rotate while air cooling with air, mating material: stainless steel ring, peripheral speed: 0.25 m / sec, pressure 0.59 MPa, test distance 150
A friction test was conducted under the test conditions of m, and the peeling state of the surface treatment agent layer after the test was visually observed. 〇: The rubber base material was not exposed. △: The surface treatment agent layer was worn and was worn. A part of the rubber substrate is exposed. ×: The surface treatment agent layer is worn and the rubber substrate on the wear surface is entirely exposed or the rubber substrate is worn.

(5) Adhesion test between elastic bodies The above surface treatment agent solution was applied to a vulcanized rubber sheet (60 × 25 × 2 mm) with a thickness of about 1 μm by spraying, and after being heat-treated at 150 ° C. for 10 minutes, 40 ° C, 95% R between surface-treated rubber sheets
H in a constant temperature / humidity chamber, and pressure-bonded at a surface pressure of 1.5 × 10 ^-2 MPa for 24 hours.Then, at room temperature, tensile shear adhesion strength test method (JIS K
-6850) to evaluate the surface tackiness by measuring the tensile strength of the tensile shear bond strength test specimen

(6) High temperature adhesion test with metal Surface treated vulcanized fluoro rubber used for static friction measurement test
The O-ring is compressed 25% with a JIS K-6301 compression device (compression surface: stainless steel buffing), placed in a thermostat at 120 ° C for 24 hours, cooled to room temperature for 5 hours, and then between the compression surface Is measured, and the presence or absence of the surface treatment agent layer is visually observed. Δ: No peeling of the surface treatment agent layer, ×: Peeling of the surface treatment agent layer 2
Rating on a scale

(7) Leak test of seal material A helium leak test was performed on the vulcanized fluoro rubber O-ring used in the static friction measurement test of (3) to evaluate the presence or absence of leakage.

Example 2 The various tests of Example 1 were performed on a thermoplastic elastomer molded article, not on a vulcanized fluororubber.

In each of the following comparative examples, the following examples were used.
In place of the surface treatment agent solution of No. 1, the following surface treatment agent solutions were used, respectively.

Comparative Example 1 Ethyl cellulose 10 parts Toluene 590 parts

Comparative Example 2 10 parts of silane coupling agent of Example 1 590 parts of toluene

Comparative Example 3 Silicone rubber of Example 1 20 parts Ethyl cellulose 80 parts Toluene 5900 parts

Comparative Example 4 Silicone rubber of Example 1 20 parts Silane coupling agent of Example 1 80 parts Toluene 5900 parts

Comparative Example 5 Ethyl cellulose 20 parts 80 parts of the silane coupling agent of Example 1 Toluene 5900 parts

Comparative Example 6 Methyl silicone oil (Shin-Etsu Chemical KF96) 2 parts Toluene 98 parts

Comparative Example 7 10 parts of wax emulsion (PYN-411 on the other hand, oil and fat product; solid content concentration 30% by weight) Silicone oil emulsion 5 parts (Shin-Etsu Chemical KM742; solid content concentration 28% by weight) Ethyl cellulose 1 part Ethanol 1000 parts However, the coating thickness on the fluoro rubber vulcanizate was changed to about 5 μm.

Comparative Example 8 Hydroxyl Group-Containing Fluoroolefin-Alkyl Vinyl 100 Parts Ether Copolymer Polytetrafluoroethylene Powder 120 Parts Silicone Rubber Powder 40 Parts Graphite 40 Parts Methyl Ethyl Ketone 1000 Parts It was changed to about 10 μm.

The results of the measurements and evaluations in the above Examples and Comparative Examples are shown in the following table. Table Example Comparative example Measurement and evaluation items 1 2 1 2 3 4 5 6 7 8 Coatability test Visual observation ○ ○ ○ × ○ ○ ○ × △ ○ Dynamic friction measurement test Surface dynamic friction coefficient 0.05 0.05 1.1 0.8 0.10 0.07 1.0 0.05 0.05 0.15 Static friction measurement test Static friction coefficient tanθ 0.36 0.36>1.7> 1.7 0.84 0.84 0.84> 1.7 0.84 0.36 Abrasion test Visual observation ○ ○ × × × ○ × △ ○ ○ Adhesion test between elastic bodies Tensile strength (× 10 ^-2 MPa ) 2.9 2.9 0 8.8 2.9 2.9 7.8 2.0 0 0 High-temperature adhesion test with metal Adhesion force (Kg) 0 0 10 10 5 5 10 0 2 10 Leak test of sealing material Leakage existence No No Yes Yes No No No No Yes Yes

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[Procedure amendment]

[Submission date] July 21, 2000 (2007.2)
1)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0032

[Correction method] Change

[Correction contents]

Example 2 The various tests of Example 1 were performed not on a vulcanized fluororubber but on a molded article of a urethane-based thermoplastic elastomer.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4F006 AA04 AA14 AA18 AA22 AA42 AB03 AB39 AB67 BA02 BA09 BA12 CA00 CA04 DA00 DA04 EA05 4J002 AB03X CP03W CP08W CP14W EX026 EX036 EX066 EX076 EX086 FD010 FD206 JGH30 J05C03J03BA BA JC36 MA07 MA09 MA14 NA02 NA10 NA11 NA24 PB06 PC07

Claims (3)

[Claims] 1. A silane coupling agent having an average molecular weight of about 10
A surface treatment agent comprising 10,000 to 1,000,000 silicone polymers and an organic solvent-soluble cellulose derivative. 2. The method according to claim 1, which is prepared as an organic solvent solution.
The surface treating agent according to the above. 3. A vulcanized rubber molded article or resin elastic body molded article surface-treated with the surface treating agent according to claim 1.