JP2007204576A - Organopolysiloxane composition for bonding magnesium alloy and composite article - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organopolysiloxane composition for bonding magnesium alloys having a good self-adhesivity to magnesium alloys and a composite article of its cured material and a magnesium alloy. <P>SOLUTION: The organopolysiloxane composition for bonding magnesium alloys contains (A) an organopolysiloxane having a methoxy group at the terminal, (B) an organosilicon compound having not less than three silicon atom-bonding hydrolyzable groups and/or its partially hydrolyzed product in the molecule and (C) an organic compound obtained by mixing and reacting (N) an organic compound having an isocyanate group in the molecule and (K) an organic compound containing a carboxylic acid at a mole ratio of (N)/(K)=0.8-2.0. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an organopolysiloxane composition for adhering a magnesium alloy that exhibits excellent magnesium alloy adhesiveness by room temperature curing and a composite article of the cured product and a magnesium alloy.

  In recent years, magnesium alloys represented by AZ-31, AZ-91, etc. have been characterized by their light weight, high strength, corrosion resistance, designability, and recyclability. It is widely used for transportation equipment members such as information electronic equipment such as MD players and DVD recorders, electrical parts, automobile oil pans, intake manifolds, lock housing parts, steering upper brackets, steering wheels, etc. There has been a need for organopolysiloxane compositions for adhering magnesium alloys that have good self-adhesive properties.

  However, since these magnesium alloys are very difficult to adhere to adherends, chemical conversion treatment is indispensable for adhesion, and many studies have been conducted on sealing materials and adhesives that exhibit good self-adhesion without treatment. Was not made. That is, only a few examples have been proposed so far for organopolysiloxane compositions having self-adhesive properties to magnesium alloys. Japanese Patent Publication No. 2003-535152 (Patent Document 1) proposes a composition using a curable silicone and an amino group-containing silane adhesion promoter as a filler. Japanese Patent Laid-Open No. 2002-309219 (Patent Document 2) proposes a composition using a silicone oil and an inorganic compound containing a metal element having a smaller ionization tendency than magnesium as a filler. However, for the former, the effectiveness of amino group-containing silane adhesion promoters such as γ-aminopropyltrialkoxysilane and trialkoxypropylethylenediamine is insufficient, and the latter is limited to the filler used. It lacks the freedom of material design.

  Moreover, as a recent technique, in Japanese Patent Application Laid-Open No. 2005-298558 (Patent Document 3), by using an acidic silane coupling agent in which the pH of a 5% aqueous solution of an acidic silane coupling agent is 7 or less, magnesium is used. A technique for improving the adhesion to the alloy has been proposed, but even if such an acidic silane coupling agent is used, the magnesium alloy corrodes due to the acidity of the silane coupling agent, and the magnesium alloy itself A decrease in strength occurs. Alternatively, since there are few kinds of acidic silane coupling agents, the degree of freedom in material design is low, and the cost is disadvantageous.

Special table 2003-535152 gazette JP 2002-309219 A JP 2005-298558 A

  The present invention has been made in view of the above circumstances, and provides an organopolysiloxane composition for adhering to a magnesium alloy having good self-adhesiveness to a magnesium alloy and a composite article of the cured product and the magnesium alloy. Objective.

  In order to achieve the above object, the present inventor has focused on the particularity of the magnesium alloy adherend, and as a result, mixed an organic compound having an isocyanate group in the molecule with an organic compound containing a carboxylic acid. The present inventors have found that the use of a reacted organic compound dramatically improves the adhesiveness, and has led to the present invention.

（式中、Ｒ及びｎは上記の通りであり、Ｍｅはメチル基、Ｘは酸素原子又は炭素原子数２〜５のアルキレン基であり、ｍは独立に０又は１である。）
で示されるオルガノポリシロキサン、及び下記一般式（３）：

〔式中、Ｒ、Ｍｅ、Ｘ及びｍは上記の通りであり、ｐは１０以上の整数であり、ｑは１〜５の整数である。また、Ｒ¹は下記式（４）

（式中、Ｒ、Ｍｅ、Ｘ、ｍは上記の通りである。）
で示される加水分解性基を含む分岐鎖である。〕
で示されるオルガノポリシロキサンから選ばれる１種又は２種以上のオルガノポリシロキサン：１００質量部、
（Ｂ）一分子中にケイ素原子に結合した加水分解可能な基を少なくとも３個有する有機ケイ素化合物及び／又はその部分加水分解物：０．１〜５０質量部、
（Ｃ）分子内にイソシアネート基を有する有機化合物（Ｎ）と、カルボン酸を含有する有機化合物（Ｋ）をモル比（Ｎ）／（Ｋ）＝０．８〜２．０の範囲内で混合し、反応させた有機化合物：０．１〜１５質量部
を含有してなるマグネシウム合金接着用オルガノポリシロキサン組成物を提供するものである。 Therefore, the present invention
(A) The following general formula (1):
HO (SiR ₂ O) _n H (1)
(In the formula, R is the same or different monovalent hydrocarbon group having 1 to 10 carbon atoms, which is unsubstituted or substituted, and n is an integer of 10 or more.)
An organopolysiloxane represented by the following general formula (2):

(In the formula, R and n are as described above, Me is a methyl group, X is an oxygen atom or an alkylene group having 2 to 5 carbon atoms, and m is independently 0 or 1).
And the following general formula (3):

[Wherein, R, Me, X and m are as described above, p is an integer of 10 or more, and q is an integer of 1 to 5. R ¹ represents the following formula (4)

(In the formula, R, Me, X and m are as described above.)
It is a branched chain containing the hydrolyzable group shown by these. ]
One or more organopolysiloxanes selected from the organopolysiloxanes represented by: 100 parts by mass,
(B) an organosilicon compound having at least three hydrolyzable groups bonded to a silicon atom in one molecule and / or a partial hydrolyzate thereof: 0.1 to 50 parts by mass;
(C) An organic compound (N) having an isocyanate group in the molecule and an organic compound (K) containing a carboxylic acid are mixed within a molar ratio (N) / (K) = 0.8 to 2.0. Then, an organopolysiloxane composition for adhering a magnesium alloy, comprising 0.1 to 15 parts by mass of a reacted organic compound is provided.

  The organopolysiloxane composition of the present invention is a composition in which an organic compound having an isocyanate group in the molecule and an organic compound containing a carboxylic acid are mixed and reacted to significantly improve the adhesion. It is.

〔式中、Ｒは同一又は異種の炭素原子数１〜１０の非置換もしくは置換の一価の炭化水素基であり、Ｍｅはメチル基であり、Ｘは酸素原子又は炭素原子数２〜５のアルキレン基であり、ｎは１０以上の整数であり、ｍは独立に０又は１であり、ｐは１０以上の整数であり、ｑは１〜５の整数である。また、Ｒ¹は下記式（４）

（式中、Ｒ、Ｍｅ、Ｘ、ｍは上記の通り）で示される加水分解性基を含む分岐鎖である。〕 [(A) component]
The organopolysiloxane of component (A) used in the present invention is one or a mixture of two or more organopolysiloxanes represented by the following general formulas (1) to (3).

[In the formula, R is the same or different, unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms, Me is a methyl group, and X is an oxygen atom or 2 to 5 carbon atoms. An alkylene group, n is an integer of 10 or more, m is independently 0 or 1, p is an integer of 10 or more, and q is an integer of 1 to 5. R ¹ represents the following formula (4)

(Wherein R, Me, X, and m are as described above) are branched chains containing a hydrolyzable group. ]

  (A) R in the general formulas (1) to (3) and formula (4) showing the organopolysiloxane of the component is an unsubstituted or substituted monovalent carbonization having 1 to 10 carbon atoms, particularly 1 to 6 carbon atoms. A hydrogen group, for example, an alkyl group such as a methyl group, an ethyl group or a propyl group; a cycloalkyl group such as a cyclohexyl group; an alkenyl group such as a vinyl group or an allyl group; an aryl group such as a phenyl group or a tolyl group; And a group in which a hydrogen atom bonded to a silicon atom is partially substituted with a halogen atom, for example, a 3,3,3-trifluoropropyl group. The plurality of R in the general formulas (1) to (4) may be the same group or different groups.

  X in the general formulas (2), (3), and (4) is an oxygen atom or an alkylene group having 2 to 5 carbon atoms. Examples of the alkylene group include an ethylene group, a propylene group, and a butylene group. Etc. are exemplified.

n is an integer of 10 or more, and in particular, the diorganopolysiloxane has an viscosity at 25 ° C. in the range of 25 to 500,000 mPa · s, and preferably in the range of 500 to 100,000 mPa · s. m is independently 0 or 1.
P is an integer of 10 or more, preferably an integer such that the viscosity of this organopolysiloxane at 25 ° C. is in the range of 500 to 500,000 mPa · s, particularly preferably in the range of 1,000 to 100,000 mPa · s. , Q is an integer of 1-5, preferably 1-3. In addition, in this invention, a viscosity shows the value in 23 degreeC measured with the rotational viscometer.

[Component (B)]
The component (B) used in the present invention is an organosilicon compound having at least three hydrolyzable groups bonded to a silicon atom in one molecule and / or a partial hydrolyzate thereof. What is represented by the general formula (5) is preferable.
R ² _a SiR ³ _4-a (5)
(In the formula, R ² is a monovalent hydrocarbon group and R ³ is a hydrolyzable group. A is 0 or 1, preferably 1.)

Examples of the hydrolyzable group (R ³ ) of the organosilicon compound (B) and its partial hydrolyzate include a ketoxime group, an alkoxy group, an acetoxy group, and an isopropenoxy group.
Further, the remaining group (R ² ) bonded to the silicon atom other than the hydrolyzable group is not particularly limited as long as it is a monovalent hydrocarbon group. Specifically, a methyl group, an ethyl group, Examples thereof include monovalent hydrocarbon groups having 1 to 10 carbon atoms such as alkyl groups such as propyl group and butyl group, alkenyl groups such as vinyl group, and aryl groups such as phenyl group. Among these, a methyl group, an ethyl group, a vinyl group, and a phenyl group are preferable.

  Specific examples of such component (B) include tetrakis (methyl ethyl ketoxime) silane, methyl tris (dimethyl ketoxime) silane, methyl tris (methyl ethyl ketoxime) silane, ethyl tris (methyl ethyl ketoxime) silane, methyl tris (methyl isobutyl ketoxime) silane. , Ketoxime silanes such as vinyltris (methylethylketoxime) silane, methyltrimethoxysilane, vinyltrimethoxysilane, phenyltrimethoxysilane, tetramethoxysilane, vinyltriethoxysilane, alkoxysilanes such as tetraethoxysilane, methyltriacetoxy Acetoxysilanes such as silane and vinyltriacetoxysilane, and methyltriisopropenoxysilane and vinyltriisopropenoxy Silane, isopropenoxysilane silanes such as phenyltrimethoxysilane isopropenoxysilane silane, and the like partially hydrolyzed condensate of the silane. These may be used alone or in combination of two or more.

  (B) The compounding quantity of a component is the range of 0.1-50 mass parts with respect to 100 mass parts of (A) component, Preferably it is the range of 5-30 mass parts. If the amount is less than 0.1 parts by mass, sufficient crosslinking cannot be obtained, and it is difficult to obtain a composition having the desired rubber elasticity.

[Component (C)]
The organic compound (N) having an isocyanate group in the molecule of the component (C) and the organic compound (K) containing a carboxylic acid are mixed and reacted with each other, and the resulting organic compound adheres well to the composition of the present invention. It is essential in the composition of the present invention that imparts properties.

Specific examples of the organic compound (N) containing an isocyanate group in the molecule include methyl isocyanate, ethyl isocyanate, isopropyl isocyanate, isobutyl isocyanate, phenyl isocyanate, vinyl isocyanate, tolyl isocyanate, naphthyl isocyanate. Examples thereof include organic compounds having a general isocyanate group such as silane coupling agents having an isocyanate group such as 3-isocyanatopropyltrimethoxysilane and 3-isocyanatopropyltriethoxysilane. Here, the organic compound containing an isocyanate group exemplified is a very general compound, but a special and complex compound other than this illustration may be used.
There are many organic compounds (K) containing a carboxylic acid, and among these, it is most desirable to use acetic acid.

  Here, the mixing ratio of the organic compound (N) having an isocyanate group in the molecule and the organic compound (K) containing a carboxylic acid is (N) / (K) = 0.8 to 2.0 in molar ratio. Within the range, more preferably within the range of (N) / (K) = 0.9 to 1.2. When the molar ratio is less than 0.8, since many unreacted carboxylic acid groups are present, the component (C) becomes acidic, the magnesium alloy is corroded, and the strength of the magnesium alloy is reduced. In addition, since unreacted carboxylic acid groups are present, the storage stability of the composition also deteriorates. Moreover, since the isocyanate group becomes excessive when the molar ratio exceeds 2.0, the adhesiveness is lowered.

  The reaction method of the organic compound (N) having an isocyanate group in the molecule and the organic compound (K) containing a carboxylic acid is an organic compound (K) having an isocyanate group in the molecule and an organic compound (K) ) Are mixed and heated at room temperature or about 60 to 70 ° C., the reaction quickly occurs.

のような構造となり、また、この構造を有する化合物は容易に脱炭酸し、下記式（７）

のような構造になる。 Here, when the organic compound (N) having an isocyanate group in the molecule and the organic compound (K) containing a carboxylic acid react, the following formula (6)

Further, a compound having this structure is easily decarboxylated, and the following formula (7)

It becomes the structure like this.

  In the present invention, the organic compound (N) having an isocyanate group in the molecule of the component (C) and the organic compound (K) containing a carboxylic acid are mixed and reacted with each other, the organic compound represented by the above formula (6), ( 7) which may have either structure, and within the above-mentioned mixing ratio range, an organic compound (N) having an isocyanate group in an unreacted molecule or an organic compound (K) containing a carboxylic acid May be present.

  The compounding quantity of the organic compound (C) which mixed the organic compound (K) which contains the organic compound (N) which has an isocyanate group in a molecule | numerator, and the carboxylic acid was made to react with respect to 100 mass parts of (A) component. 0.1 to 15 parts by mass, preferably 0.2 to 10 parts by mass. If the amount is less than 0.1 parts by mass, sufficient adhesion of the magnesium alloy cannot be obtained.

[(D) component]
In the present invention, (D) a filler can be blended, and as the filler, reinforcing or non-reinforcing fillers for imparting rubber physical properties to the present composition can be used. Specific examples of such fillers include surface-treated or untreated fumed silica, precipitated silica, wet silica, carbon powder, talc, bentonite, surface-treated or untreated calcium carbonate, zinc carbonate, magnesium carbonate, Surface-treated or untreated calcium oxide, zinc oxide, magnesium oxide, aluminum oxide, aluminum hydroxide and the like are exemplified, and these can be used alone or in combination of two or more.

  The blending amount of the filler is preferably used in the range of 1 to 500 parts by mass with respect to 100 parts by mass of the component (A), and if it is less than 1 part by mass, sufficient for the target magnesium alloy due to insufficient rubber strength. Adhesive strength may not be obtained, and if it exceeds 500 parts by mass, the viscosity of the material increases and workability may be inferior. Preferably it is the range of 5-450 mass parts.

[Other ingredients]
In addition, in the present invention, generally known additives and catalysts other than the above components may be used as long as they do not adversely affect the curability at room temperature and the self-adhesiveness to the magnesium alloy. Additives include colorants such as polyethers, pigments and dyes as thixotropy improvers, heat resistance improvers such as Bengala and cerium oxide, cold resistance improvers, rust preventives, and improved oil resistance such as potassium methacrylate. An antifungal agent, an antibacterial agent, etc. are added as needed. Examples of the catalyst include an organic tin ester compound, an organic tin chelate compound, an alkoxy titanium compound, a titanium chelate compound, and a silicon compound having a guanidyl group.

[Preparation of composition]
The method for preparing the organopolysiloxane composition of the present invention is not particularly limited, and can be obtained by mixing predetermined amounts of the above components according to a conventional method. Moreover, although the said organopolysiloxane composition hardens | cures by leaving to stand at room temperature, the well-known method and conditions according to the kind of composition can be employ | adopted for the shaping | molding method, hardening conditions, etc.
When used for bonding a magnesium alloy, the organopolysiloxane composition of the present invention exhibits good self-adhesiveness even without chemical conversion treatment for the magnesium alloy.
The curing conditions for the organopolysiloxane composition may be the same as those for a normal room temperature curable condensation curable silicone rubber composition, and generally 23 ± 2 ° C./50±5% RH. The curing condition of curing for 7 days under the environment is adopted.

  In addition, the magnesium alloy used in the present invention is not particularly limited, for example, for die casting, for casting, for spreading. Specifically, AZ31, AZ91, AZ60, AS41, AS21 (ASTM standard display) etc. are mentioned.

  Furthermore, the composite article includes information electronic equipment such as a mobile phone, digital video, digital camera, liquid crystal projector, plasma display, personal computer, MD player, DVD recorder, electrical parts, automobile oil pan, intake manifold, lock housing part, Transportation equipment members such as a steering upper bracket and a steering wheel are listed.

  EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated concretely, this invention is not restrict | limited to the following Example. In addition, in the following example,% shows the mass% and a viscosity shows the value in 23 degreeC measured with the rotational viscometer.

[Example 1]
100 parts by mass of polydimethylsiloxane having a viscosity at 23 ° C. of 50,000 mPa · s and a terminal end blocked with a hydroxyl group, 80 parts by mass of colloidal calcium carbonate whose surface is treated with fatty acid, and heavy calcium carbonate 20 with an untreated surface After adding parts by mass and mixing with a mixer, 9 parts by mass of methyltrimethoxysilane, 1.5 parts by mass of diisopropoxytitanium bisacetylacetonate, isopropyl isocyanate (P) and acetic acid (G) in molar ratio (P) /(G)=1.0 mixed and reacted organic compound (pH of 5% aqueous solution of this organic compound was 7.8, confirmed to be alkaline) 2 parts by mass was added, and the pressure was reduced. Mix thoroughly underneath to obtain Composition 1.

[Example 2]
100 parts by mass of zinc oxide and 10 parts by mass of fumed silica whose surface was treated with dimethyldichlorosilane were added to 100 parts by mass of polydimethylsiloxane having a viscosity at 23 ° C. of 50,000 mPa · s and the end blocked with a trimethoxy group. , 4 parts by mass of vinyltrimethoxysilane, 3 parts by mass of diisopropoxytitanium bisacetylacetonate, isopropyl isocyanate (P) and acetic acid (G) in a molar ratio (P) / (G) = 1 And 2 parts by weight of an organic compound mixed and reacted (note that the pH of a 5% aqueous solution of this organic compound was 8.0 and confirmed to be alkaline) was added completely under reduced pressure. The composition 2 was obtained by mixing.

[Comparative Example 1]
Example 1 is the same as Example 1 except that 2 parts by mass of the organic compound obtained by mixing and reacting isopropyl isocyanate (P) and acetic acid (G) in Example 1 at a molar ratio (P) / (G) = 1.0 is not blended. In the same manner, Composition 3 was obtained.

[Comparative Example 2]
Isopropyl isocyanate (P) and acetic acid (G) in Example 1 were mixed at a molar ratio (P) / (G) = 1.0 and replaced with isopropyl isocyanate (P) and acetic acid ( G) The molar ratio of (P) / (G) = 0.5 was mixed and reacted with the organic compound (note that the pH of a 5% aqueous solution of this organic compound was 5.5, confirming that it was acidic. The composition 4 was obtained in the same manner as in Example 1 except that the above was used.

[Comparative Example 3]
Isopropyl isocyanate (P) and acetic acid (G) in Example 1 were mixed at a molar ratio (P) / (G) = 1.0 and replaced with isopropyl isocyanate (P) and acetic acid ( G) The molar ratio of (P) / (G) = 3.0 was mixed and reacted with the organic compound (note that the pH of a 5% aqueous solution of this organic compound was 8.9 and confirmed to be alkaline. The composition 5 was obtained in the same manner as in Example except that was used.

These silicone rubber compositions were poured into a 2 mm mold and cured at 23 ° C. and 50% RH for 7 days to obtain a rubber sheet having a thickness of 2 mm. Table 1 shows the results of measuring the physical properties of rubber (hardness, elongation at break, tensile strength) from a 2 mm thick sheet according to JIS K6249.
In addition, a shear adhesion test body having an adhesion area of 2.5 mm ² and an adhesion thickness of 1 mm was produced from this silicone rubber composition using magnesium alloy plates (AZ-91, AZ-31) having a width of 25 mm and a length of 100 mm. . After curing for 7 days at 23 ° C. and 50% RH, measurement was performed according to JIS K6850, and shear adhesion and cohesive failure rate were measured. The results are also shown in Table 1.

Claims (4)

(A) The following general formula (1):
HO (SiR ₂ O) _n H (1)
(In the formula, R is the same or different monovalent hydrocarbon group having 1 to 10 carbon atoms, which is unsubstituted or substituted, and n is an integer of 10 or more.)
An organopolysiloxane represented by the following general formula (2):

(In the formula, R and n are as described above, Me is a methyl group, X is an oxygen atom or an alkylene group having 2 to 5 carbon atoms, and m is independently 0 or 1).
And the following general formula (3):

[Wherein, R, Me, X and m are as described above, p is an integer of 10 or more, and q is an integer of 1 to 5. R ¹ represents the following formula (4)

(In the formula, R, Me, X and m are as described above.)
It is a branched chain containing the hydrolyzable group shown by these. ]
One or more organopolysiloxanes selected from the organopolysiloxanes represented by: 100 parts by mass,
(B) an organosilicon compound having at least three hydrolyzable groups bonded to a silicon atom in one molecule and / or a partial hydrolyzate thereof: 0.1 to 50 parts by mass;
(C) An organic compound (N) having an isocyanate group in the molecule and an organic compound (K) containing a carboxylic acid are mixed within a molar ratio (N) / (K) = 0.8 to 2.0. And reacted organic compound: an organopolysiloxane composition for adhesion of magnesium alloy, containing 0.1 to 15 parts by mass.   The organopolysiloxane composition for adhesion to magnesium alloys according to claim 1, wherein the organic compound (K) containing the carboxylic acid of component (C) is acetic acid. Furthermore, (D) at least 1 sort (s) of filler: The organopolysiloxane composition for magnesium alloy adhesion of Claim 1 or 2 formed by containing 1-500 mass parts. A composite article obtained by bonding a cured product of the organopolysiloxane composition according to claim 1, 2 or 3 and a magnesium alloy.