JPH1036770A - Aqueous coating composition for synthetic rubber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject composition containing different kinds of specific polysiloxanes in a specific ratio, capable of expressing good adhesivity to the surfaces of synthetic rubbers and capable of imparting excellent non-adhesivity and slipperiness to the surfaces of the rubbers. SOLUTION: This aqueous coating composition comprises (A) 0.05-50wt.% of a compound of formula I (R<1> is a monovalent 1-20C hydrocarbon group; L is 5,000-50,000) having an elasticity complex modulus of 6×10<6> to 1×10<10> cp at 25 deg.C, (B) 0.3-70wt.% of a compound of formula II R<2> is R<1> ; R<3> is H, R<1> ; 0.2<=(n)/[(m)+(n)]<=1, and 1<=[(m)+(n)]<=1,000}, (C) 0.01-10wt.% of a curing catalyst, (D) 0.1-20wt.% of a surfactant, and (E) the balance water. The components A and B are contained in an A/B weight ratio of 5/95 to 70/30. The composition is useful for coating rubbers for tire bladders, rubbers for gaskets, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aqueous coating agent for synthetic rubber having excellent adhesion to a substrate, non-adhesion, and slipperiness.

[0002]

2. Description of the Related Art Hitherto, a method of surface treatment with a silicone resin composition has been proposed in order to impart non-adhesiveness and slipperiness to the surface of various rubber materials. For example, a method using a composition comprising a diorganopolysiloxane having both hydroxyl groups blocked and an epoxy group-containing organopolysiloxane and an aminoalkyl group-containing silane or an aminoalkyl group-containing siloxane and an organohydrogenpolysiloxane (JP-B-56-47864, JP-A-56-78960),
A method using a composition comprising a hydrolyzed condensate of a diorganopolysiloxane capped at both ends with hydroxyl groups and a dialkoxysilane containing an aminoalkyl group, an organohydrogenpolysiloxane, and an organic metal salt (see JP-A-7-109441).
However, these are used by diluting them with an organic solvent, and in this respect, there is a problem in the influence on the environment and the safety for users and the like.

[0003] Efforts have been made to develop aqueous compositions to solve these problems. For example, a method using an aqueous composition comprising dimethylpolysiloxane, polyalkylene glycol and a clay mineral (Japanese Patent Publication No. 52-43982, Japanese Patent Application Laid-Open No. 50-28553, Japanese Patent Application Laid-Open No. 57-111393, Japanese Patent Application No.
2), a method using an aqueous organopolysiloxane emulsion containing a diorganopolysiloxane containing a graft polymerized chain as a main component (see JP-A-7-109440), a branched silicone and an aminoalkyl. A method using an aqueous composition comprising a group-containing trialkoxysilane (see Japanese Patent Application Laid-Open No. H7-179820) and the like.

A method using an aqueous composition comprising a hydrolyzed condensate of a diorganopolysiloxane at both ends and a dialkoxysilane containing an aminoalkyl group and an organohydrogenpolysiloxane (see Japanese Patent Application Laid-Open No. Hei 7-126417). A method using an aqueous composition comprising a diorganopolysiloxane having a terminal hydroxyl group blocked, an epoxy group-containing organopolysiloxane, an amino group-containing silane (or an amino group-containing siloxane) and an organohydrogenpolysiloxane (see Japanese Patent Publication No. 54-43023) Using an aqueous composition comprising an epoxy group-containing organopolysiloxane and an amino group-containing both-terminal alkoxy-blocked or hydroxyl-blocked organopolysiloxane (see Japanese Patent Publication No. 3-77765), an amino-containing polysiloxane and methyltrimethoxysilane Partially hydrolyzed condensate and A method of using an aqueous composition comprising Ganoderma functional silane and the catalyst (U
SP 5,366,808), a method using an aqueous composition comprising dimethylpolysiloxane and methylhydrogensilane and / or methyltrimethoxysilane (JP-A-57-111394).
And a method using an aqueous composition comprising a polyorganosiloxane having a viscosity of 3,000 to 5,000,000 cSt, methyl hydrogen polysiloxane, silica and a catalyst (see Japanese Patent Publication No. 7-88015).

[0005]

However, none of these aqueous compositions have sufficient adhesiveness, non-adhesiveness, and slipperiness with the synthetic rubber surface. The present inventors have intensively studied an aqueous coating composition for synthetic rubber which solves the above problems and arrived at the present invention.

[0006]

DISCLOSURE OF THE INVENTION The present invention is an aqueous coating composition for synthetic rubber which can solve these problems, and comprises the following (A), (B), (C), (D),
It consists of each component of (E), and (A) component weight / (B)
An aqueous coating composition for synthetic rubber, wherein the component weight is 5/95 to 70/30. (A) 0.05 to 50% by weight of an organopolysiloxane represented by the following general formula (Formula 1) and having a complex viscosity at 25 ° C. of 6 × 10 ⁶ to 1 × 10 ¹⁰ cp;

Embedded image (Wherein R ¹ is a monovalent hydrocarbon group having 1 to 20 carbon atoms, and L is 5,000 ≦ L ≦ 50,000) (B) Organohydrogenpolysiloxane represented by the following general formula (Formula 2)

Embedded image [Wherein R ² is a monovalent hydrocarbon group having 1 to 20 carbon atoms, R ³ is a hydrogen atom or R ² , m, and n are 0.2 ≦ n / (m + n) ≦ 1, 1 ≦ (m + n) ≦ 1,000 (C) 0.01 to 10% by weight of a curing catalyst, (D) 0.1 to 20% by weight of a surfactant, and (E) the balance of water.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. The component (A) constituting the aqueous coating composition of the present invention is an organopolysiloxane represented by the general formula (Chemical Formula 1) and having a complex viscosity at 25 ° C. of 6 × 10 ⁶ to 1 × 10 ¹⁰ cp. R ^{1 in the} general formula (Chemical Formula 1) is ¹ having 1 to 20 carbon atoms.
Examples of the hydrocarbon group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, alkyl groups such as n-hexyl group, n-octyl group, n-decyl group, n-dodecyl group, n-tetradecyl group, n-hexadecyl group and n-octadecyl group; cycloalkyl groups such as cyclopentyl group and cyclohexyl group; Aryl groups such as a phenyl group and a tolyl group, and groups in which part or all of the hydrogen atoms bonded to carbon atoms of these groups have been substituted with halogen atoms, for example, 3,3,3
-Trifluoropropyl group and the like, and it is particularly preferable that 90% or more is a methyl group.

Here, the complex viscosity is easily measured by a commercially available general measuring device. For example, "Controlled stress rheometer CS type" (Borin),
Using “Ares viscoelasticity measurement system (for fluid measurement)” (manufactured by Rheometric Scientific),
The measurement may be performed at a low fixed frequency, for example, 0.1 rad / s.

If the complex viscosity at 25 ° C. of the organopolysiloxane is less than 6 × 10 ⁶ cp, the resulting composition does not show sufficient adhesion to the synthetic rubber surface, non-adhesion and slipperiness, If it exceeds 1 × 10 ¹⁰ cp, a stable aqueous composition cannot be obtained. Therefore, the complex viscosity of this organopolysiloxane at 25 ° C. is preferably 6 × 10 ⁶ to 1 × 10 ¹⁰ cp, more preferably Is 8 × 10 ⁶ to 1 × 10
⁸ cp.

The component (B) constituting the aqueous coating composition of the present invention is an organohydrogenpolysiloxane represented by the general formula (Formula 2). General formula (Formula 2)
R ² is a monovalent hydrocarbon group having 1 to 20 carbon atoms, and examples thereof include the same as R ¹ . And n /
If the value of (m + n) is less than 0.2, the adhesiveness to the synthetic rubber surface, non-adhesiveness and slipperiness are not sufficiently exhibited.
0.2 ≦ n / (m + n) ≦ 1 is preferred, more preferably
0.5 ≦ n / (m + n) ≦ 1. (M + n) is 1,
When it exceeds 000, the resulting aqueous coating composition becomes unstable, so that preferably 1 ≦ (m + n) ≦ 1,000, more preferably 20 ≦ (m + n) ≦ 200.

The compounding amount of the component (A) in the present invention is 0.05
If it is less than 10% by weight, it does not show adhesion to the synthetic rubber surface,
If it exceeds 50% by weight, adhesion, non-adhesiveness and slipperiness with the synthetic rubber surface are not sufficiently exhibited, so it is preferably 0.05 to 50% by weight, more preferably 0.5 to 20% by weight.

In the present invention, the content of the component (B) is 0.3
When the amount is less than 70% by weight, the adhesiveness to the synthetic rubber surface, non-adhesiveness, and slipperiness are not sufficiently exhibited. When the amount exceeds 70% by weight, the adhesiveness to the synthetic rubber surface is not sufficiently exhibited.
It is preferably 70% by weight, more preferably 3 to 40% by weight.

In the present invention, the weight ratio of component (A) to component (B) is preferably in the range of component (A) / component (B) = 5/95 to 70/30. Those exhibiting sufficient adhesion, non-adhesiveness and slipperiness with synthetic rubber, more preferably in the range of (A) component weight / (B) component weight = 10/90 to 50/50.

The component (C) constituting the aqueous coating composition of the present invention is a curing catalyst selected from organic zinc compounds, organic titanium compounds, organic tin compounds and the like. When these usable substances are listed, zinc laurate, zinc acetate, zinc stearate, tin octylate, zinc octylate, tetrapropyl titanate and its partially hydrolyzed condensate, tetrabutyl titanate and its partially hydrolyzed condensate, Examples include bisdipropoxytitanium, bis (acetylacetonate) titanium oxide, titanium lactate, ammonium titanium lactate, dibutyltin dilaurate, dibutyltin dioctate, dioctyltin dilaurate, and dioctyltin diacetate.

In the present invention, the amount of the component (C) is 0.1%.
If the amount is less than 01% by weight, the coating film has no catalytic effect and becomes sticky. If the amount exceeds 10% by weight, the effect does not change and it becomes uneconomical, so it is preferably 0.01 to 10% by weight, more preferably 0.1 to 5% by weight. Range.

The component (D) in the present invention is a surfactant, and is not particularly limited. Examples thereof include anionic surfactants such as alkyl sulfates, alkylbenzene sulfonates and alkyl phosphates, polyoxyethylene alkyl ethers, Polyoxyethylene alkyl phenyl ether,
Nonionic surfactants such as sorbitan alkylate and polyoxyethylene sorbitan alkylate; cationic surfactants such as quaternary ammonium salt and alkylamine acetate; amphoteric surfactants such as alkyl betaine and alkyl imidazoline; be able to.

In the present invention, the compounding amount of the component (D) is 0.1
When the amount is less than 20% by weight, the storage stability of the composition is reduced, and the water layer and the oil layer are separated, and the wettability to the synthetic rubber is deteriorated. When the amount exceeds 20% by weight, the coating film becomes sticky. , 0.1 to 20% by weight, more preferably 1 to 10% by weight.

The aqueous coating composition of the present invention can be prepared, for example, by adding the organopolysiloxane of the component (A) and the organohydrogenpolysiloxane of the component (B) to the surfactant of the component (D). Emulsified and dispersed in water,
It is prepared by adding the curing catalyst of component (C) thereto. The component (A) and the component (B) may be respectively emulsified and dispersed. However, since the component (A) alone has a high viscosity, it is difficult to obtain a composition having good storage stability.
A method of emulsifying and dispersing a mixed solution of the components (A) and (B) is preferable. When the component (C) is insoluble in water, it may be dissolved in a solvent such as alcohol in advance, mixed with the surfactant of the component (D), or dissolved in water using the surfactant of the component (D). It is preferable to dissolve or disperse in water by a method such as emulsified emulsion.

The aqueous coating composition of the present invention comprises
It is optional to appropriately add a thickener, an antifoaming agent, a pigment, an inorganic powder, a preservative, and the like as needed. The aqueous coating agent composition of the present invention thus prepared is useful as a coating agent for synthetic rubber, and the coating method using the same can be, for example, brushing, roll coating, spray coating, knife coating the composition. Then, it is applied to the synthetic rubber surface by a method such as dip coating, and then heated in an oven.

The synthetic rubbers that can be used in the composition of the present invention are listed below: butyl rubber, EPDM rubber, SBR, NB
Examples thereof include R, nitrile rubber, acrylic rubber, and fluorine rubber, but usable objects are not limited to these.

[0021]

EXAMPLES Next, the present invention will be described in more detail with reference to examples and comparative examples of the present invention. However, the present invention is not limited to these examples.
The complex viscosity of the organopolysiloxane represented by (e) is a value measured by the following method, and the viscosity of the organohydrogenpolysiloxane represented by the chemical formulas (f) to (h) in Examples is 25 ° C. It is a measured value in. The methods for evaluating the surface slipperiness and durability of the rubber material in the examples are based on the measurement results obtained by the following methods. The number of each component composition in Table (1) indicates% by weight.

The above chemical formulas (a) to (h) are shown below (in the formula, Ph represents a phenyl group). These are referred to in the following examples simply as organopolysiloxane (a).
Abbreviated as (A) (CH ₃ ) ₃ Si-O-[(CH ₃ ) ₂ SiO] ₇₉₀₀ -Si (CH ₃ ) ₃ , (b) (CH ₃ ) ₃ Si-O-[(CH ₃ ) ₂ SiO] ₆₆₀₀ -Si (CH ₃ ) ₃ , (c) (CH ₃ ) ₃ Si-O-[(CH ₃ ) ₂ SiO] ₈₈₀₀ -[(Ph) ₂ SiO] _90-
Si (CH ₃ ) ₃ , (d) (CH ₃ ) ₃ Si-O-[(CH ₃ ) ₂ SiO] ₅₀₀₀ -Si (CH ₃ ) ₃ , (e) HO (CH ₃ ) ₂ Si-O- [ (CH ₃ ) ₂ SiO] ₇₂₀₀ -Si (CH ₃ ) ₂ OH
, (F) (CH ₃ ) ₃ Si—O— [H (CH ₃ ) SiO] ₃₈ —Si (CH ₃ ) ₃ , (g) (CH ₃ ) ₃ Si—O — [(CH ₃ ) ₂ SiO] _28- [H (CH ₃ ) SiO] ₇₀ -S
i (CH ₃ ) ₃ , (h) (CH ₃ ) ₃ Si-O-[(CH ₃ ) ₂ SiO] _24- [H (CH ₃ ) SiO] ₄ -Si
(CH _{3) 3.}

[Organopolysiloxanes (a) to (e)]
Complex Viscosity Measurement Method] Using a controlled stress rheometer type CS (manufactured by Bolin Corporation), using a 20 mmφ cone plate as a fixture, and at 25 ° C, a complex viscosity having a fixed frequency of 0.1 rad / s. Was measured.

(Evaluation Method of Surface Slipperiness) As shown in FIG. 1, butyl rubber 1 (25 × 35 mm, thickness 2 mm) treated with the coating agent of the present invention was adhered to an aluminum plate 3.
A load of 0 g was applied, and the coefficient of kinetic friction with the untreated butyl rubber 2 was measured at a tensile speed of 10 cm / min.

(Evaluation method of durability) As shown in FIG. 2, untreated butyl rubber 2 (width
20 mm, thickness 2 mm), butyl rubber 1 (150 x 50 mm, thickness 2 mm) treated with the coating agent of the present invention, a thrust load of 2 kg was applied, and speed = 60 reciprocations / min, one-way stroke length When reciprocating friction under the condition of
The number of reciprocations until the surface of the treated butyl rubber 1 was scraped was measured.

[Example 1] As shown in FIG. 3, an anchor-type stirring device 6 capable of stirring the entire inside of a stainless steel container (inner diameter 30 cm) having a capacity of 5 L and small tooth-like projections on the periphery are vertically arranged. Agitating means 8 (diameter 4
cm), a high-shearing device 7 having two types of stirring devices is provided to form a composite emulsifying device 9 having a complex viscosity of 2.4 × 10 ⁷ cp.
A mixture of 720 g of this organopolysiloxane (a) and 1,680 g of an organohydrogenpolysiloxane (f) having a viscosity of 20 cp, 440 g of polyoxyethylene (additional moles = 8) lauryl ether and 160 g of water were charged. Then, high-shear stirring was performed for 30 minutes with the anchor-type stirring device 6 at 15 rpm and the high-shearing device 7 at 1,000 rpm. As a result, a uniform transparent grease-like composition was obtained.
At 5 rpm, the high shearing device 7 was set to 300 rpm, and 1,000 g of water was added thereto and stirred for 30 minutes to obtain an oil-in-water organopolysiloxane emulsion.

330 g of the obtained organopolysiloxane emulsion was diluted with 660 g of water, and 80 g of a 9% by weight zinc acetate emulsion containing 1.5% by weight of lauryltrimethylammonium chloride and 10 g of sodium carboxymethylcellulose were added. And This coating composition is applied to the surface of butyl rubber with a brush and placed in a hot-air circulating thermostat adjusted to 150 ° C.
After standing for 15 minutes, the surface slippage and durability were evaluated, and the results are shown in (Table 1).

Example 2 The organopolysiloxane (a) and the organohydrogenpolysiloxane (f) in Example 1 were combined with 960 g of the organopolysiloxane (b) having a complex viscosity of 1.3 × 10 ⁷ cp and the organohydrogenpolysiloxane. (F) A coating agent composition was prepared in exactly the same manner as in Example 1 except that the amount was changed to 1,440 g. This was treated on the surface of butyl rubber, and the surface slipperiness and durability were evaluated by the method described above. The results are shown in (Table 1).

Example 3 The organopolysiloxane (a) and the organohydrogenpolysiloxane (f) in Example 1 were combined with 360 g of the organopolysiloxane (c) having a complex viscosity of 3.6 × 10 ⁷ cp and the organohydrogenpolysiloxane. (F) A coating agent composition was prepared in exactly the same manner as in Example 1 except that the amount was 2,040 g, and this was treated on the surface of butyl rubber, and the surface slipperiness and durability were evaluated.
The results are shown in (Table 1).

Example 4 The organopolysiloxane (a) and the organohydrogenpolysiloxane (f) in Example 1 were replaced with 360 g of the organopolysiloxane (a) and 2,040 g of the organohydrogenpolysiloxane (g) having a viscosity of 140 cs. A coating composition was prepared in exactly the same manner as in Example 1 except that g was used, and this was treated on the surface of butyl rubber, and the surface slipperiness and durability were evaluated. The results are shown in (Table 1).

Example 5 A coating composition was prepared in exactly the same manner as in Example 1 except that 80 g of the emulsified emulsion of 9% by weight of zinc acetate in Example 1 was replaced with 24 g of a 30% solution of bisdipropoxytitanium in isopropyl alcohol. This was treated on the surface of butyl rubber, and the surface slipperiness and durability were evaluated. The results are shown in (Table 1).

Comparative Example 1 480 g of organohydrogenpolysiloxane (f) and 48 g of polyoxyethylene (additional moles = 8) lauryl ether were placed in a beaker having an internal volume of 1 L.
After mixing with a homomixer, 272 g of water was gradually added and emulsified and dispersed in water.
Secondary emulsification was performed under a pressure of cm ² to obtain an emulsion of organohydrogenpolysiloxane (f). 330 g of the obtained emulsion was diluted with 660 g of water, and 80 g of a 9% by weight zinc acetate emulsion emulsified with 1.5% by weight of lauryltrimethylammonium chloride and 10 g of sodium carboxymethylcellulose were added to obtain an aqueous coating composition. This composition was applied to the surface of butyl rubber with a brush, left in a hot-air circulating thermostat adjusted to 150 ° C. for 15 minutes, and then evaluated for surface slipperiness and durability. The results are shown in Table 1.

Comparative Example 2 2,400 g of organopolysiloxane (b), polyoxyethylene (number of moles added: 8)
Example 1 containing 440 g of lauryl ether and 160 g of water
An oil-in-water type organopolysiloxane emulsion was obtained in the same manner as described above. 330 g of the organopolysiloxane emulsion obtained above was diluted with 660 g of water, and 80 g of a 9% by weight zinc acetate emulsified emulsion containing 1.5% by weight of lauryl trimethylammonium chloride and 10 g of sodium carboxymethylcellulose were added. And Using the aqueous coating composition, the surface of butyl rubber was treated in the same manner as in Example 1, and the surface slipperiness and durability were evaluated. The results are shown in Table 1.

Comparative Example 3 Example 1 was repeated except that the organopolysiloxane (a) in Example 1 was replaced with an organopolysiloxane (d) having a complex viscosity of 5.1 × 10 ⁶ cp.
A coating agent composition was prepared in the same manner as described above, and this was treated on the surface of butyl rubber, and the surface slipperiness and durability were evaluated. The results are shown in Table 1.

Comparative Example 4 A coating composition was prepared in the same manner as in Example 1 except that the organopolysiloxane (a) in Example 1 was replaced with an organopolysiloxane (e) having a complex viscosity of 1.8 × 10 ⁷ cp. Was prepared and treated on the surface of butyl rubber to evaluate the surface slipperiness and durability,
The results are shown in (Table 1).

[Comparative Example 5] A coating agent composition was prepared in the same manner as in Example 1 except that the organohydrogenpolysiloxane (f) in Example 1 was replaced with an organohydrogenpolysiloxane (h) having a viscosity of 25 cs. A product was prepared and treated on the surface of butyl rubber to evaluate the surface slipperiness and durability. The results are shown in Table 1.

Comparative Example 6 A coating composition was prepared in the same manner as in Example 1 except that the 9% by weight zinc acetate emulsified emulsion in Example 1 was not used, and this was applied to the surface of butyl rubber. , Surface slipperiness and durability were evaluated, and the results are shown in (Table 1).

[0038]

[Table 1]

[0039]

The rubber material coated with the composition of the present invention is useful for tire bladders, automotive weather strips, O-rings, gaskets, and the like.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a dynamic friction coefficient measuring method for evaluating surface slippage.

FIG. 2 is an explanatory diagram of a measurement method for evaluating durability.

FIG. 3 is an explanatory diagram of a complex emulsification device used in an example.

[Explanation of symbols]

 1 butyl rubber treated with the coating agent of the present invention, 2 untreated butyl rubber, 3 aluminum plate, 4 load, 5 metal plate, 6 anchor type stirring device, 7 high shearing device, 8 disk type stirring means, 9 complex emulsification apparatus.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Satoshi Kuwata 1-10 Hitomi, Matsuida-cho, Usui-gun, Gunma Prefecture Shin-Etsu Chemical Co., Ltd. Silicone Electronic Materials Technology Laboratory

Claims (1)

[Claims] 1. The following (A), (B), (C), (D),
It consists of each component of (E), and (A) component weight / (B)
An aqueous coating composition for synthetic rubber, wherein the component weight is 5/95 to 70/30. (A) 0.05 to 50% by weight of an organopolysiloxane represented by the following general formula (Chemical Formula 1) and having a complex viscosity at 25 ° C. of 6 × 10 ⁶ to 1 × 10 ¹⁰ cp. (Wherein R ¹ is a monovalent hydrocarbon group having 1 to 20 carbon atoms, L is 5,000 ≦ L ≦ 50,000) (B) 0.3 to 70% by weight of an organohydrogenpolysiloxane represented by the following general formula (Formula 2) Embedded image [Wherein R ² is a monovalent hydrocarbon group having 1 to 20 carbon atoms, R ³ is a hydrogen atom or R ² , m, and n are 0.2 ≦ n / (m + n) ≦ 1, 1 ≦ (m + n) ≦ 1,000 (C) 0.01 to 10% by weight of a curing catalyst, (D) 0.1 to 20% by weight of a surfactant, and (E) the balance of water.