KR101475567B1 - Silicon Coating Composition Having an Excellent Slippery Ability for Rubber Substrate - Google Patents

Abstract

The present invention relates to a composition for rubber coating excellent in slipperiness, abrasion resistance and weather resistance. More particularly, the present invention relates to a silicone coating composition having excellent adhesion performance comprising a methylhydrogen-modified polysiloxane, a non-reactive polysiloxane, a silane derivative, a polyethylene wax, an organic solvent and silica.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a silicone composition for rubber coating,

The present invention relates to a composition for rubber coating excellent in slipperiness, abrasion resistance and weather resistance. More particularly, the present invention relates to a silicone coating composition having excellent adhesion performance comprising a methylhydrogen-modified polysiloxane, a non-reactive polysiloxane, a silane derivative, a polyethylene wax, an organic solvent and silica.

Organic rubber is used as a sealing material in various industries such as electric, electronic and automobile to cut off external contaminants and prevent noise and leakage. However, general rubber has excellent sealing ability, but slip property and weather resistance of rubber are lengthened, so that friction noise may occur or the appearance may change with time. In order to overcome these problems, the surface of rubber is treated with a silicone coating agent to improve slipperiness and weatherability.

Silicone oils are typical components used in coatings that require slip and weather resistance. As such silicone oil, reactive polysiloxane and the like are widely used. The reactive polysiloxane reacts with a material to be treated to impart abrasion resistance to the material, and has an advantage in that the material has slip property by an outwardly oriented alkyl group.

However, it is preferable that the slip performance is exhibited even if only a small amount of such a coating additive is used, but the necessary slip performance can not be sufficiently exhibited when using a small amount of the coating additive. This is because the adhesion between the reactive polysiloxane and the material to be treated is poor.

Generally, in the case of a material having an uneven surface or a material treated with a plasma or the like, the adhesion to the silicone oil is good, but the surface of the NR, BR and EPDM rubbers, which are widely used, Slip performance and other physical properties are not exhibited.

International Patent Application No. PCT / US2004 / 011319 discloses a waterborne waterborne coating composition comprising boron nitride, a high molecular weight silicone resin, at least one resin binder, and at least one crosslinker.

However, the composition of International Patent Application No. PCT / US2004 / 011319 additionally contains a boron nitride, a resin binder and a crosslinking agent which are not included in the composition of the present invention.

In addition, U.S. Patent No. 7,368,174 discloses a composition for rubber coating comprising an additive such as polysiloxane, polyurethane, and urethane cross-linking agent, heat-resistant filler.

However, the invention of U.S. Patent No. 7,368,174 further includes a polyurethane, a urethane crosslinking agent and a heat resistant filler which are not included in the composition of the present invention.

The above-mentioned compositions for rubber coating according to the prior art are used for coating compositions which necessarily contain boron nitride, a resin binder and a crosslinking agent or a polyurethane, a urethane crosslinking agent and a heat-resistant filler in order to impart abrasion resistance, weather resistance and slip property to a rubber material Should be used.

In order to overcome the disadvantages of the prior art, the inventors of the present invention focused attention on the fact that the slip property, the abrasion resistance, and the weather resistance of the rubber can be increased by the composition for coating the polysiloxane-based rubber without boron nitride or polyurethane It came to the invention.

An object of the present invention is to provide a composition for rubber coating which is excellent in slipperiness, abrasion resistance and weather resistance, and which comprises a composition for rubber coating comprising a methylhydrogen-modified polysiloxane, a non-reactive polysiloxane, a silane derivative, a polyethylene wax, an organic solvent and silica will be.

The object of the present invention described above can be achieved by providing a composition for rubber coating comprising a methylhydrogen-modified polysiloxane, a non-reactive polysiloxane, a silane derivative, a polyethylene wax, an organic solvent and silica.

The rubber coating composition of the present invention is a composition corresponding to the subject of a three-component rubber coating agent of a subject, a curing agent and a catalyst, and is used in combination with a curing agent and a catalyst to improve physical properties such as abrasion resistance, slipperiness and weatherability .

The curing agent that can be used in combination with the rubber coating composition of the present invention may be a mixture of 5 wt% to 15 wt% of glycidylpropyltrimethoxysilane and 85 wt% to 95 wt% of isopropyl alcohol, Or more.

In addition, the catalyst that can be used together with the rubber coating composition of the present invention may be, but is not limited to, a mixture of dibutyltin diacetate and toluene containing 1 wt% to 5 wt% of tin.

The term "polysiloxane" in the present invention means a polymer having the formula H ₃ Si- (O-SiH ₂ ) _n O-SiH ₃ , wherein a silicon atom and an oxygen atom alternately bond to form a chain.

In the present invention, the term "methylhydrogen-modified polysiloxane" means a polysiloxane derivative having the following structural formula.

Wherein R ₁ is methyl, ethyl, propyl, or butyl, R ₂ is hydrogen, and x and y are each independently an integer of 1 to 1,000.

The term "non-reactive polysiloxane" in the present invention means a polysiloxane in which the repeating unit of the polysiloxane, H contained in (O-SiH ₂ ) is replaced by a non-reactive substance such as a methyl group, an alkyl group having a large molecular weight,

The term "silane derivative" in the present invention means a silane substituted with an amino group and at least one alkoxy group.

The term " polyethylene wax (PE wax) "in the present invention is a low molecular weight solid polyethylene having an average molecular weight in the range of 500 to 10,000, which is a solid at room temperature,

The rubber coating composition of the present invention may contain 1 wt% to 5 wt% of the methylhydrogen-modified polysiloxane, 1 wt% to 5 wt% of the non-reactive polysiloxane, 1 wt% to 3 wt% of the silane derivative, It is preferable that the wax is contained in an amount of 1 wt% to 5 wt%, the organic solvent in an amount of 80 wt% to 95.5 wt%, and the silica in an amount of 0.5 wt% to 2 wt%.

When the methylhydrogen-modified polysiloxane is contained in an amount of less than 0.5 wt% in the coating composition of the present invention, adhesion between the rubber and the coating composition may be deteriorated. In addition, when the methylhydrogen-modified polysiloxane is contained in an amount of more than 2 wt% in the coating composition of the present invention, the flexibility of the coating film is lowered and the durability against external impact, that is, abrasion resistance may be lowered.

In addition, when the non-reactive polysiloxane is contained in an amount of less than 1 wt% in the coating composition of the present invention, the dispersion stability and slipperiness of the coating composition of the present invention may be reduced. Moreover, when the non-reactive polysiloxane is contained in an amount of more than 5 wt% in the coating composition of the present invention, the viscosity of the coating composition of the present invention is increased, and unreacted polysiloxane remains after coating, Can occur.

The surface tension of the methylhydrogen-modified polysiloxane and the non-reactive polysiloxane used in the coating composition of the present invention is as low as 20 dyne / cm and is excellent in releasability, lubricity, water repellency and weather resistance. In addition, the methylhydrogen-modified polysiloxane and the non-reactive polysiloxane are advantageous in that they are stable to an oxidizing atmosphere, ozone, ultraviolet rays and heat.

The coating composition of the present invention is realized as a dispersion of a low viscosity and a high concentration containing such a methylhydrogen-modified polysiloxane and a non-reactive polysiloxane, so that even if only a small amount of the coating composition is used, . Therefore, the use of the coating composition of the present invention can reduce the cost of the rubber coating process.

When the silane derivative is contained in an amount of less than 1 wt% in the coating composition of the present invention, the silane derivative has low reactivity with the rubber and the polysiloxane, so that the adhesion performance required for the coating composition of the present invention is hardly shown . Furthermore, when the silane derivative is contained in an amount of more than 3 wt% in the coating composition of the present invention, the flexibility of the coating film may be lowered and the durability against external impact may be lowered.

The methylhydrogen-modified polysiloxane contained in the composition for rubber coating of the present invention preferably contains a hydrogel group of 2.3 mmol / g to 16 mmol / g, more preferably 4.3 mmol / g to 16 mmol / g.

When the methylhydrogen-modified polysiloxane contains a hydrogel group of less than 2.3 mmol / g, the reactivity with the silane derivative contained in the coating composition of the present invention is lowered, and the desired adhesion and slipperiness are not obtained.

The viscosity of the non-reactive polysiloxane contained in the rubber coating composition of the present invention is preferably 50,000 cP to 500,000 cP.

When the viscosity of the non-reactive polysiloxane is less than 50,000 cP, the dispersion stability of the coating composition of the present invention is lowered. In addition, when the viscosity of the non-reactive polysiloxane exceeds 500,000 cP, the viscosity of the coating composition of the present invention increases and the coating workability decreases.

If the content of the polyethylene wax contained in the rubber coating composition of the present invention is less than 1 wt%, the slipping property of the coating composition of the present invention may be deteriorated. When the content of the polyethylene wax contained in the rubber coating composition of the present invention is more than 5 wt%, the relative content of silicon in the rubber coating composition of the present invention decreases, and the weatherability and durability of the coating composition deteriorate .

The silane derivative contained in the rubber coating composition of the present invention plays a role of improving the adhesion between the composition of the present invention and the rubber.

The melting point of the polyethylene wax contained in the rubber coating composition of the present invention is preferably from 60 캜 to 150 캜.

If the melting point of the polyethylene wax is higher than 150 ° C, adhesion of the polyethylene wax may deteriorate and leveling of the material may be lowered when a low bake hardening temperature is applied to the coating composition of the present invention.

The boiling point of the organic solvent contained in the rubber coating composition of the present invention is preferably 80 to 160 ° C. The organic solvent is preferably toluene or xylene.

If the boiling point of the organic solvent is less than 80 캜, the evaporation speed of the organic solvent during the curing of the coating composition of the present invention is high, and the leveling is lowered and the appearance of the coated rubber is not good.

The silica included in the composition for rubber coating of the present invention may be organically-treated. The organically treated silica refers to a silica to which a functional group such as hexamethyldisilazane (HMDZ) or trimethylhydrogensilane is bonded to the silica surface.

The term " organically treated silica "in the present invention means silica obtained by treating the surface of silica with an organic compound.

The silica is added as a matting agent for controlling the gloss of the rubber coated by the coating composition of the present invention.

Dispersions having excellent adhesion performance and slip performance can be realized by using the rubber coating composition of the present invention. In addition, the rubber coating composition has a low external viscosity, so that the composition has excellent workability, stability in preparation, and storage stability.

Further, by using the composition for rubber coating of the present invention, it is possible to suppress noise generated during rubbing between materials due to non-slip property of the rubber surface.

Hereinafter, the present invention will be described in more detail with reference to the following examples. However, the following description of the embodiments is intended to illustrate specific embodiments of the present invention and is not intended to limit or limit the scope of the present invention.

Example  1 - 7

Methylhydrogenpolysiloxane and methylhydrogen-dimethylpolysiloxane were used as the methylhydrogen-modified polysiloxane, and two viscosity-unreactive polysiloxanes were used as the non-reactive polysiloxane. As the silane derivative, aminopropyltriethoxysilane or polyethylene wax having melting point of 60 占 폚 to 150 占 폚 was used. Toluene was used as an organic solvent, and silica of 6 μm particle size organically treated as silica was used.

The method for preparing the composition of Example 1-7 according to the present invention is as follows. 20 wt% of methylhydrogen-modified polysiloxane and non-reactive polysiloxane, polyethylene wax, silica and toluene were added thereto, followed by stirring at a speed of 3,000 rpm for 3 hours using a dissolver. Thereafter, the silane derivative and the remaining amount of the organic solvent were added, and the mixture was stirred at a rate of 1,000 RPM for 1 hour to prepare a composition for rubber coating. The content of each of the thus-prepared compositions is shown in Table 1 below.

Component (wt%) Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Methylhydrogen-modified polysiloxane 15.5 mmol / g 1.8 1.3 1.3 1.3 1.3 1.3 7.3 mmol / g 1.3 Non-reactive polysiloxane 100,000 cP 4 4 2 2 2 300,000 cP 2 4 Silane derivative Aminopropyltriethoxysilane 1.5 1.5 2 2 2 2 2 PE wax Melting point: 60 ° C to 150 ° C 2.5 2.5 3.5 3.5 3.5 2.5 3.5 Organic solvent toluene 89.4 89.9 90.4 90 90.4 89.4 90.4 Silica Particle size:
6 μm 0.8 0.8 0.8 1.2 0.8 0.8 0.8 Sum 100 100 100 100 100 100 100

Comparative Example  1 - 14

Comparative Example 1-14 is the same as the method of preparing the composition of Example 1-7, but the kind and application amount of the raw materials used are shown in Tables 2 and 3 below.

Component (wt%) Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Comparative Example 7 Methylhydrogen-modified polysiloxane 15.5 mmol / g 0.3 2.5 1.3 1.3 1.3 1.3 7.3 mmol / g 1.3 Non-reactive polysiloxane 100,000 cP 3 300,000 cP 3 3 3 0.5 7 800,000 cP 3 Silane derivative Aminopropyltriethoxysilane 1.5 1.5 1.5 1.5 1.5 1.5 1.5 PE wax Melting point: 60 ° C to 150 ° C 2.5 2.5 2.5 2.5 3.5 3.5 3.5 Organic solvent toluene 91.9 89.7 90.9 90.9 89.9 92.4 85.9 Silica Particle size:
6 μm 0.8 0.8 0.8 0.8 0.8 0.8 0.8 Sum 100 100 100 100 100 100 100

Component (wt%) Comparative Example 8 Comparative Example 9 Comparative Example 10 Comparative Example 11 Comparative Example 12 Comparative Example 13 Comparative Example 14 Methylhydrogen-modified polysiloxane 15.5 mmol / g 1.3 1.3 1.3 1.3 1.3 1.3 1.3 Non-reactive polysiloxane 300,000 cP 3 3 3 3 3 3 3 Silane derivative Aminopropyltriethoxysilane 0.5 4 1.5 1.5 1.5 1.5 Methyltriethoxysilane 1.5 PE wax Melting point: 60 ° C to 150 ° C 2.5 2.5 2.5 0.5 7 2.5 2.5 Organic solvent toluene 91.9 88.4 90.9 92.9 86.4 91.9 89.2 Silica Particle size:
6 μm 0.8 0.8 0.8 0.8 0.8 0.3 2.5 Sum 100 100 100 100 100 100 100

The rubber coating compositions of Examples 1 to 7 and Comparative Examples 1 to 14 prepared according to the aforementioned methods were tested for basic physical properties and physical properties after coating the materials according to the following methods.

The test conditions are as follows.

1) Basic property test

1) -1 stability test

The samples were stored at 50 ℃ for 7 days, and then the occurrence of phase separation was observed.

1) -2 viscosity

The viscosity of the sample was measured using a viscometer (25 ° C, Brookfield, # 62, 200 rpm).

2) Coating property test

The prepared coating additive, the curing agent and the catalyst were added in the order of 90 wt%, 8 wt% and 2 wt%, and mixed. Then, the coating film was coated on the rubber surface with an air spray gun to a thickness of 3 μm to 6 μm Coating. Thereafter, it was dried at 150 ° C for 3 minutes.

The following ingredients were used as the hardener and the catalyst. The curing agent is a mixture of 10 wt% of glycidylpropyltrimethoxysilane and 90 wt% of isopropyl alcohol, and the catalyst is a mixture of dibutyltin diacetate and toluene containing 3 wt% of tin.

2) -1 Sleep test

The coated specimens were measured for static friction coefficient using a friction coefficient meter (BYK Slip Tester). The weight of the weight was 500 g, and the specimens were all coated with rubber specimens. Generally, a coating having a coefficient of friction of 0.4 or less was evaluated as excellent.

2) -2 Abrasion resistance test

The coated specimens were measured for abrasion resistance using a wear resistance tester. The peeling of the coating material on the specimen was observed according to the number of reciprocations by friction between the specimen and the fiber. (O: good, and X: poor) on the basis of 10,000 times in the present invention, since it may be different depending on the type of material frictioned with the test piece.

2) -3 gloss test

The coated specimens were measured for gloss at 60 DEG using a BYK Gloss meter. In the present embodiment, a matte type with a glossiness of 3 or less is set as a target.

The stability of the coating composition and the slip resistance, abrasion resistance and gloss test results after the specimen treatment are shown in Table 4 below.

division Basic Properties Coating property safety Viscosity Slipperiness Abrasion resistance Polish standard No separation 100 cP or less 0.4 or less 10,000 cP or more (○) 3 or less Example 1 No separation 62 0.3 ○ 2.4 Example 2 No separation 60 0.25 ○ 2.3 Example 3 No separation 48 0.31 ○ 2.2 Example 4 No separation 58 0.24 ○ 2.3 Example 5 No separation 72 0.28 ○ 2.7 Example 6 No separation 78 0.22 ○ 2.8 Example 7 No separation 50 0.25 ○ 2.8 Comparative Example 1 No separation 60 0.38 × 2.8 Comparative Example 2 No separation 70 0.45 × 2.9 Comparative Example 3 No separation 62 0.38 × 2.8 Comparative Example 4 detach 35 0.28 ○ 3.8 Comparative Example 5 No separation 130 0.45 ○ 2.8 Comparative Example 6 detach 41 0.28 ○ 3.1 Comparative Example 7 No separation 72 0.48 ○ 3.2 Comparative Example 8 No separation 60 0.37 × 2.3 Comparative Example 9 No separation 58 0.42 × 2.8 Comparative Example 10 No separation 60 0.4 × 2.4 Comparative Example 11 No separation 45 0.55 ○ 3.5 Comparative Example 12 No separation 110 0.24 × 2.5 Comparative Example 13 No separation 55 0.25 ○ 4.5 Comparative Example 14 No separation 105 0.45 ○ 1.1

Claims (12)

Wherein the curing agent comprises 5 wt% to 15 wt% of glycidylpropyltrimethoxysilane and 85 wt% or less of a polyhydric alcohol, a methylhydrogen-modified polysiloxane, a non-reactive polysiloxane, a silane derivative, a polyethylene wax, an organic solvent, silica, To 95 wt% of isopropyl alcohol. delete The composition for rubber coating according to claim 1, wherein the methylhydrogen-modified polysiloxane contains a hydrogen group of 2.3 mmol / g to 16 mmol / g. The rubber coating composition according to claim 1, wherein the non-reactive polysiloxane has a viscosity of 50,000 cP to 500,000 cP. The composition for rubber coating according to claim 1, wherein the silane derivative comprises an amino group and at least one alkoxy group. The composition for rubber coating according to claim 1, wherein the melting point of the polyethylene wax is from 60 캜 to 150 캜. The composition for rubber coating according to claim 1, wherein the organic solvent has a boiling point of 80 to 160 ° C. The composition for rubber coating according to claim 1, wherein the organic solvent is toluene or xylene. The composition for rubber coating according to claim 1, wherein the silica is organic-treated. delete delete The composition for rubber coating according to claim 1, wherein the catalyst is a mixture of dibutyltin diacetate and toluene containing 1 wt% to 5 wt% of tin.