JPH06166821A - Composition for molding elastomer - Google Patents

Abstract

PURPOSE: To prepare an elastomer-forming composition which is composed of two liquid parts and gives good unprimed adhesion, by placing a noble metal catalyst only in the first part and placing a specific silane or silicone compound component in the second part of the composition.

CONSTITUTION: The objective composition comprising (A) a vinyl containing polyorganosiloxane having on average two silicon atoms, (B) an organo-silicon compound containing on average three Si-H groups, (C) a noble metal catalyst, (D) a silane containing an epoxy-functional group and an alkoxy-functional group or an organo-silicone compound of the formula [R⁰ is,(substituted) hydrocarbon group having less than 8 carbon atoms; R' is a hydrocarbon group containing olefinic unsaturated group and having more than 6 carbon atoms; R" is a monovalent hydrocarbon group, hydrocarbon-oxy group or oxygen- containing hydrocarbon group; (c) is 0-3; (x),(y) and (Z) are each ≥1, and (z)≥2 when C=0], (E) a metal compound such as acetyl acetonate of aluminum, iron or zinc, is prepared by placing the component C in the first part and placing the component D in the second part of the composition which is composed of two parts.

COPYRIGHT: (C)1994,JPO

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to elastomeric molding compositions having good primerless (undercoat) adhesion. In particular, it relates to a composition provided as a two-part composition.

[0002]

2. Description of the Related Art Two-component elastomer molding silicone compositions are known. A particularly useful type of silicone elastomer molding composition is of the type in which an elastomer is molded through an addition reaction. This type of composition has the advantage that no by-products are formed upon curing, so that the resulting elastomeric product has substantially the same dimensions as the uncured elastomer and is less accurate. It is particularly useful in extremely important fields of application. The fact that the dimensions during curing are constant means that, for example,
For products that cure by a condensation reaction, this is the case when the generation of by-products such as alcohol does not cause the product to shrink somewhat during cure.

Many addition reaction silicone elastomer molding compositions require an undercoat of the surface to which they are applied in order to obtain good adhesion. This is especially true when the surface is metal or plastic. Attempts have been made to produce addition reaction elastomeric molding compositions having improved primerless adhesion to metals or plastics. For example, US Pat. No. 4,087,585 describes certain hydroxylated vinyl-containing polysiloxanes, vinyl-containing polydiorganosiloxanes, organosilicon compounds having at least three silicon-bonded hydrogen atoms, platinum catalysts and at least Disclosed is a self-adhesive silicone composition consisting of a silane having one epoxy-containing organic residue and an alkoxy group. This material exhibits good primerless adhesion to aluminum when heated at 150 ° C for at least 15 minutes. It has been found that a composition very similar to this needs to be heated to a temperature of at least 100 ° C. to achieve primerless adhesion to many substrates.

JP-A-60-101146 describes a composition which gives improved primerless adhesion even when cured at low temperatures. The publication describes a polyorganosiloxane having at least 2 units per molecule, the silicon atom of which has an alkenyl substituent.
0 parts by weight, polyorganohydrogen siloxane having at least two silicon-bonded hydrogen atoms per molecule, 0.1 to 20 parts by weight of an epoxy compound, 0.01 to 10 parts by weight of an organoaluminum compound, and improved. Also disclosed are compositions containing catalytic amounts of platinum, palladium or rhodium compounds that exhibit good adhesion.

European Application No. 240 333 describes finely dispersed curing compositions and thermal curing prepared by reacting an organopolysiloxane, a curing agent, an alkoxy group-containing organosilicon compound and a compound of Al or Zr. Curable thermosetting compositions containing a continuous phase of a thermosetting resin are disclosed. European Patent Application No. 493 791 describes improved adhesion containing alkenyl groups, organohydrogensiloxanes, platinum-containing catalysts, organosilicon compounds containing alkoxy groups and optionally epoxy groups, and zirconium compounds. Curable organopolysiloxane compositions having are described.

However, the above-mentioned JP-A-60-10 is used.
1146, European Application Nos. 240 333 and 4
The composition according to 93 791 is very effective in improving some adhesion properties, but is unstable when it is stored for some time. There is also no indication of how these compositions can be made stable. Therefore, there is a need to improve it in such a way that the composition is stable.

[0007]

The present inventors have found that a stable composition can be obtained by making the composition a two-part system and separating the catalyst and the epoxy-functional silane. Accordingly, the present invention provides (A) polyorganosiloxane having an average of about 2 silicon-bonded vinyl groups per molecule, and (B) an organosilicon having an average of at least 3 silicon-bonded hydrogen atoms per molecule. Compound,
(C) a noble metal catalyst, (D) a silane having at least one epoxy functional group and at least one alkoxy functional group, or the following general formula: (R ⁰ O) _c R ⁰ _3-c SiO (R ⁰ ₂ SiO ) _x (R'R ⁰ SiO) _y (R "R ⁰ SiO) _z SiOR ⁰ _3-c (OR ⁰ ) _c (wherein R ⁰ has 8 or less carbon atoms and has ether oxygen) Optionally represents a monovalent hydrocarbon group or a substituted hydrocarbon group, R ′ represents a hydrocarbon group having olefinic unsaturation and having at least 6 carbon atoms,
R "represents a monovalent hydrocarbon group or hydrocarbon oxy group, a halogenated hydrocarbon group or hydrocarbon oxy group, or a hydrocarbon group or hydrocarbon oxy group containing oxygen in the form of an ether bond or a hydroxyl group. , R ″ contains an epoxy group, c is 0, 1, 2 or 3, x, y and z are at least 1, and when c is 0, z is at least 2. ) Organosilicon compound, and (E) aluminum acetylacetonate,
A storage stable elastomer molding composition containing a metal compound selected from the group consisting of iron acetylacetonate, zinc acetylacetonate or aluminum salts of fatty acids, wherein the composition comprises two parts and the above-mentioned components ( C) is present only in the first part of the composition, and component (D) above is only present in the second part of the composition.

Component (A) of the composition of the present invention preferably has the general formula: Vi- [SiR ₂ O] n-SiR ₂ Vi, where Vi represents a vinyl group and R is at most 8 per group.
Represents an organic residue selected from a monovalent hydrocarbon group or a halogen-substituted hydrocarbon group having 4 carbon atoms, and n is an integer. ) Is included in the polyorganosiloxane.
These preferred polyorganosiloxanes are substantially linear polymers, although minor amounts of trifunctional or tetrafunctional siloxane groups may be present. Some amount of such groups is present in the polymer as branches. Although the preferred polyorganosiloxanes are endblocked with vinyldiorganosiloxane units, vinyl groups may be present in the polymer chain. Suitable polymers are those having a viscosity in the range of 20 millipascal seconds to 2000 pascal seconds, preferably 100 millipascal seconds to 50 pascal seconds. Suitable R groups include alkyl, alkenyl, aryl, chlorine or fluorine substituted alkyl, alkaryl and aralkyl groups. Examples of suitable R groups are methyl, ethyl, propyl, hexyl, phenyl,
Vinyl, butenyl, hexenyl, methylphenyl, trifluoropropyl and β (perfluoropropyl) ethyl. Most preferably at least 80% of all R groups are methyl groups. Therefore, the most preferred polyorganosiloxane (a) is α, ω-vinyl endblocked polydimethylsiloxane. Suitable polyorganosiloxanes (A) are well known and commercially available polymers.

Component (B) preferably has an average of at least 3 silicon-bonded hydrogen atoms per molecule,
The remaining substituents on the silicon atoms are organohydrogensiloxanes, which are monovalent hydrocarbon radicals having up to 8 carbon atoms. These are also well known. The silicon-bonded hydrocarbon substituents are preferably selected from alkyl groups having 1 to 6 carbon atoms and phenyl groups. Organohydrogensiloxane is R ₂ SiO, R ₃ SiO
_1/2 , RHSiO, HSiO _3/2 , RSiO _3/2 , R ₂ HS
It can be a homopolymer, a copolymer or a mixture thereof containing units such as io _1/2 and SiO ₂ (R is the same as above). Any one of 1 or less hydrogen atoms
Must be bonded to two silicon atoms. At least 80% of all R groups are preferably lower alkyl groups, most preferably methyl groups.

Suitable organosilicon compounds (B) include trimethylsiloxane, dimethylsiloxane and methylhydrogensiloxane units, copolymers of cyclic methylhydrogensiloxane, and dimethylhydrogensiloxane units, dimethylsiloxane units and methylhydrogensiloxane units. In particular, the copolymer of The organosilicon compound (B) preferably has at least 5 silicon-bonded hydrogen atoms per molecule, has trimethylsiloxane units, methylhydrogensiloxane units and optionally dimethylsiloxane units, and is 2 to about 500 mm at 25 ° C. Copolymers having a viscosity of Pascal second are preferred.

The noble metal catalyst used as component (C) of the composition of the present invention is a Group 8 metal, its complex or its compound. Component (C) is preferably a platinum compound or a complex thereof. This component is effective in catalyzing the addition reaction between the vinyl group of component (A) and the silicon-bonded hydrogen of component (B). This addition reaction is well known and is described in many reference books and publications. Suitable platinum compounds and complexes include chloroplatinic acid, platinum acetylacetonate, platinum halides and unsaturated compounds such as ethylene, propylene,
Complexes with organovinylsiloxane and styrene, hexamethyldiplatinum, PtCl ₂ , PtCl ₃ and Pt (C
N) ₃ . A preferred platinum catalyst is a complex of a platinum compound and vinyl siloxane, for example a complex of chloroplatinic acid and divinyltetramethyldisiloxane. Sufficient catalyst is used to provide a uniform and effective cure of the composition. A preferable ratio of the platinum catalyst is such that about 1 to 40 parts by weight of platinum is usually contained per 1 million parts by weight of the total of the component (A) and the component (B).

Component (D) used in the composition of the present invention
Is at least one epoxy functional group and at least one
A silane having one alkoxy functional group, or an organosilicon compound represented by the following general formula. (R ⁰ O) _c R ⁰ _3-c SiO (R ⁰ ₂ SiO) _x (R'R ⁰ SiO) _y (R "R ⁰ SiO) _z SiOR ⁰ _3-c (OR ⁰ ) _c where R ⁰ Represents a monovalent hydrocarbon group or a substituted hydrocarbon group which has 8 or less carbon atoms and may have ether oxygen, and R ′ has olefinic unsaturation and is at least 6 R "represents a hydrocarbon group having a carbon atom
Represents a monovalent hydrocarbon group or hydrocarbon oxy group, a halogenated hydrocarbon group or hydrocarbon oxy group, or a hydrocarbon group or hydrocarbon oxy group containing oxygen in the form of an ether bond or a hydroxyl group, R "contains an epoxy group, c is 0, 1, 2 or 3, x,
y and z are at least 1, and when c is 0, z is at least 2. This organosilicon compound is described in detail in GB 2,208,650.

Suitable silanes used as component (D) have the general formula: R " _a R ² _b SiR _4-ab (wherein R" and R
Is as defined above, R ² is an alkoxy group having up to 8 carbon atoms, a is 1 or 2, b is 1, 2 or 3 and a + b is 2, 3 or 4. ). Examples of suitable R ² groups are methoxy, ethoxy,
A propoxy or butoxy group. It is preferred that all R ² are methoxy or ethoxy groups. The R groups are the same as defined for component (A) and include the preferred groups for R. The R "group has the following general formula:

[0014]

[Chemical 2]

(Wherein X is a divalent hydrocarbon group, a halogenated hydrocarbon group, or a hydrocarbon group having an ether oxygen or a hydroxyl group) is an epoxy-containing group. Examples of X are methylene, ethylene, propylene, phenylene, chloroethylene, -C.
_{H 2 -O- (CH 2) 3} -, - CH 2 -O- (CH 2) 2 -O-
(CH _{2) 3} - and _{-CH 2 CH (OH) CH 2} - embraces.
Preferred R "groups have the general formula:

[0016]

[Chemical 3]

Most preferably X is alkylene or alkyleneoxyalkylene, for example-
_{(CH 2) 3 -OCH 2 -} , - (CH 2) 4 - or -CH ₂ -. It is preferable that a is 1 and b is 3.

The component (E) is a metal compound, such as aluminum acetylacetonate, iron acetylacetonate,
It is selected from zinc acetylacetonate or aluminum salts of fatty acids. Suitable examples include Al (acac) ₃ , F
e (acac) ₃ , Zn (acac) ₄ and Al [OC (O) (CH ₂ ) ₁₆ C
H ₃ ] ₃ (where acac represents acetylacetonate). Al (acac) ₃ is particularly preferred.

Additional ingredients may also be used in the compositions of the present invention. For example, filler, flame retardant, heat stabilizer, pH
Stabilizers, fungicides, colorants, pigments and solvents are mentioned. Suitable fillers include reinforced silica fillers such as pyrogenic silica and precipitated silica, resinous materials such as those consisting of units of formula: R ₃ SiO _1/2 and formula: SiO ₂ , alumina, fine quartz. Includes calcium carbonate, zinc oxide, titania and zirconium silicate.
The filler added to the composition of the present invention is preferably treated with a filler treating agent in order to improve the compatibility with other components of the composition. Such additives are generally known and include, for example, hexamethyldisilazane, alkylalkoxysilanes, methylhalogenosilanes and short chain silanol endblocked polydimethylsiloxanes. Fillers may comprise up to about 50% by weight of the total composition, but 5-40% by weight of the composition is preferred. A preferred filler is reinforced silica.

The composition according to the invention comprises 100 parts by weight of component (A), 0.5 per vinyl group present in component (A).
~ 3 components (B) sufficient to provide silicon-bonded hydrogen atoms, 0.5 to 20 parts by weight of component (D) and.
It is preferred to contain 1 to 10 parts by weight of component (E), as well as a suitable amount of the catalyst. An important requirement of the present invention is that the composition of the present invention is stored in two parts before being mixed for use, the component (C) is contained in only one part, the component (D) Is contained in another part. Component (A) is preferably present in both parts of the composition. If component (B) does not contain a curing inhibitor that can be present in both components or in either component, then component (B) should be present only in the part that does not contain component (C). Is preferred. Component (C) should be present in only one part, preferably in the absence of component (B) and in the absence of component (D) at all. The component (E) can be present in either one of them, but it is preferable that the component (D) is present in a portion not containing the component (D). Each portion of the composition is stored separately until just prior to use and is thoroughly mixed and used at the time of use.

The mixing of the two parts is accomplished by placing them in a third container and stirring. More preferably, the two components are mixed in an extrusion device that is connected to a container containing the two parts. Each part is preferably prepared by a mixing method which can be in a generous proportion, for example 1: 1 or 1:10. This proportion is usually adjusted beforehand in the extruder. During storage, it is preferable to keep the parts in moisture-impermeable packaging that does not contain substances that are harmful to, for example, platinum catalysts.

The compositions of the present invention can be cured at relatively low temperatures and provide good primerless adhesion to a wide variety of substrates. Suitable substrates include aluminum, polyvinyl chloride, polycarbonate, polyetherimide, poly (phenylene oxide) and poly (phenylene sulfone).

[0023]

EXAMPLES Examples for explaining the present invention and comparative examples for showing the improvement of the present invention will be described below. Preparation of Base Composition Part I of the base composition comprises 52 parts by weight of dimethylvinylsiloxane endblocked polydimethylsiloxane having a viscosity of 450 millipascal seconds, inert ground quartz filler 46.3.
Parts by weight, 1 part by weight of zinc oxide, 0.5 parts by weight of carbon black, and 0.2 parts by weight of a solution of a platinum complex in vinylsiloxane so that the platinum in part I is 12 ppm. Part II mixes 46.8 parts by weight of dimethylvinylsiloxane endblock polydimethylsiloxane having a viscosity of 450 millipascal seconds, 46.8 parts by weight of inert ground quartz filler and 6.3 parts by weight of trimethylsiloxane endblock polydimethylsiloxane. As a result, 37.5 mol% of dimethylsiloxane and 62.5 mol% of methylhydrogensiloxane unit.
Was manufactured.

Example 1 To 100 parts by weight of Part I above was added 1.6 parts by weight of a solution of 10% aluminum acetylacetonate in toluene. To 100 parts by weight of the above-mentioned part II, 3-2,3-
Epoxy propoxy-propyltrimethoxysilane 5.
6 parts by weight were added. After thorough stirring, each mixture was placed in a separate closed container and stored in an oven at 50 ° C for 1 week. After one week, the contents of the two containers were mixed in a 1: 1 ratio and heated to 80 ° C. for 4 hours. The elastomer obtained is satisfactory and is disclosed in JP-A-60-101146.
It was slightly softer than the comparative example based on the publication (not stored).

Example 2 100 parts by weight of Part I above, 1.6 parts by weight of a solution of 10% aluminum acetylacetonate in toluene, and a platinum complex in vinyl siloxane such that the platinum in Part I is 24 ppm. 0.1 parts by weight of the above solution were added. To 100 parts by weight of Part II above, 5.6 parts by weight of 3-2,3-epoxypropoxy-propyltrimethoxysilane was added. After thorough stirring, each mixture was placed in a separate closed container and stored in an oven at 50 ° C for 1 week. A week later,
Mix the contents of the two containers at a ratio of 1: 1 for 4 hours,
Heated to 80 ° C. The obtained elastomer was harder than that of Example 1 and the same as that of the comparative example (not stored) based on JP-A-60-101146.

Example 3 The composition of Example 2 was applied to the following substrates: polyvinyl chloride, poly (phenylene sulfone), polycarbonate, poly (phenylene oxide), poly (oxymethylene), polyetherimide, poly. (Ethylene terephthalate), poly (butylene terephthalate), glass fiber reinforced epoxy resin, aluminum, polyether sulfone. The substrate was placed in an oven at 70 ° C. for 4 hours to fully cure the silicone composition. The substrate with the cured composition was stored overnight at room temperature and tested for adhesion and cohesive adhesion. The test was performed by using a safety razor blade to cut a small portion of the cured composition from the substrate, sandwiching the distant portion and pulling it from the substrate. Adhesion failure 10 when the cured composition is completely separated from the substrate
0% was recorded, and the case where the composition was torn without separating from the substrate was recorded as 0% adhesion failure. The latter is the desired result. These intermediate results were recorded as the percentage of total area completely removed from the substrate. The results of the adhesion failure of each substrate are shown in Table 1.

[0027]

TABLE 1 Table 1 substrate adhesion failure percent polyvinyl chloride 0 poly (phenylene sulfone) 40 Polycarbonate 0 poly (phenylene oxide) 0 poly (oxymethylene) 0 polyetherimide 10 Poly (ethylene terephthalate) 0 poly (butylene Terephthalate) 0 Glass fiber reinforced epoxy resin 0 Aluminum 0 Polyether sulfone 100

Comparative Example 1 To 100 parts by weight of Part I above, 5.6 parts by weight of 3-2,3-epoxypropoxy-propyltrimethoxysilane was added. To 100 parts by weight of Part II above, a solution of 10% aluminum acetylacetonate in toluene 1.
6 parts by weight were added. After the ingredients were mixed well, each part was placed in a separate closed container and stored in an oven at 50 ° C for 1 week. After one week, the contents of the container containing Part I were discolored. The contents of the two vessels were mixed in a 1: 1 ratio and heated to 80 ° C. for 4 hours. Surprisingly, a non-useful, soft rubbery gel was obtained. This example
It shows that the composition deteriorates when stored differently from the present invention.

Comparative Example 2 93.1 parts by weight of dimethylvinylsiloxane endblock polydimethylsiloxane having a viscosity of 450 millipascal seconds,
93.1 parts by weight of inert crushed quartz filler, (viscosity 450
Millipascal-second dimethylvinylsiloxane endblock polydimethylsiloxane 80.1% by weight, zinc oxide 1
7.2 parts by weight of black paste (comprising 3.3% by weight and 6.6% by weight of carbon black), 0.2 solution of platinum complex in vinylsiloxane (having 0.6% by weight of platinum in solution) Parts by weight, (dimethylsiloxane unit 37.5 mol% and methylhydrogensiloxane unit 62.5
Trimethylsiloxane endblock polydimethylsiloxane 6.3 parts by weight, 3 to 7 per molecule
0.1 parts by weight of polydimethylvinylcyclosiloxane having siloxane units of 1.6 parts by weight of a solution of 10% aluminum acetylacetonate in toluene, and (3-glycidoxypropyl) trimethoxysilane.
By mixing 6 parts by weight, JP-A-60-1011
The composition described in Japanese Patent No. 46 was produced. The composition was stored at room temperature and was no longer flowable by 5 hours. Two
After 4 hours, the composition had cured to a solid block of silicone elastomer.

Claims (7)

[Claims] 1. A polyorganosiloxane having (A) an average of about 2 silicon-bonded vinyl groups per molecule, and (B) an organosilicon compound having an average of at least 3 silicon-bonded hydrogen atoms per molecule. , (C) a noble metal catalyst, (D) a silane having at least one epoxy functional group and at least one alkoxy functional group, or the following general formula: (R ⁰ O) _c R ⁰ _3-c SiO (R ⁰ ₂ SiO) _x (R'R ⁰ SiO) _y (R "R ⁰ SiO) _z SiOR ⁰ _3-c (OR ⁰ ) _c (wherein R ⁰ has 8 or less carbon atoms and has ether oxygen). Optionally represents a monovalent hydrocarbon group or a substituted hydrocarbon group, R ′ represents a hydrocarbon group having olefinic unsaturation and having at least 6 carbon atoms,
R "represents a monovalent hydrocarbon group or hydrocarbon oxy group, a halogenated hydrocarbon group or hydrocarbon oxy group, or a hydrocarbon group or hydrocarbon oxy group containing oxygen in the form of an ether bond or a hydroxyl group. , R ″ contains an epoxy group, c is 0, 1, 2 or 3.
x, y and z are at least 1, and when c is 0, z
Is at least 2. ) Organosilicon compounds,
And (E) a metal compound selected from the group consisting of aluminum acetylacetonate, iron acetylacetonate, zinc acetylacetonate or aluminum salt of fatty acid, which is a storage stable elastomer molding composition, wherein the composition is Comprised of two parts and above component (C)
Is present only in the first part of the composition, and the component (D) is only present in the second part of the composition. 2. The component (A) is 100 millipascal seconds to
The composition of claim 1 which is an α, ω-vinyl endblocked polydimethylsiloxane having a viscosity of 50 Pascal seconds. 3. In the component (D), R ″ is represented by the following general formula: [Where, X is _{- (CH 2) 3 -OCH 2} - group, - (CH _{2) 4} -
A group selected from a group and a —CH ₂ — group].
Is 1 and b is 3. The composition according to claim 1 or 2. 4. The composition according to claim 1, wherein the component (E) is aluminum acetylacetonate. 5. 100 parts by weight of component (A), component (A)
Component (B) sufficient to give 0.5 to 3 silicon-bonded hydrogen atoms per vinyl group present in
The composition according to any one of claims 1 to 4, containing 20 parts by weight of the component (D) and 0.1 to 10 parts by weight of the component (E). 6. Component (A) is present in two parts of the composition, component (B) is present only in the part not containing component (C), and component (E) is present in component (D). The composition according to any one of claims 1 to 5, which is present only in a portion not containing it. 7. A polyorganosiloxane having an average of about 2 silicon-bonded vinyl groups per molecule (A), and (B) an organosilicon compound having an average of at least 3 silicon-bonded hydrogen atoms per molecule. , (C) a noble metal catalyst, (D) a silane having at least one epoxy functional group and at least one alkoxy functional group, or the following general formula: (R ⁰ O) _c R ⁰ _3-c SiO (R ⁰ ₂ SiO) _x (R'R ⁰ SiO) _y (R "R ⁰ SiO) _z SiOR ⁰ _3-c (OR ⁰ ) _c (wherein R ⁰ has 8 or less carbon atoms and has ether oxygen). Optionally represents a monovalent hydrocarbon group or a substituted hydrocarbon group, R ′ represents a hydrocarbon group having olefinic unsaturation and having at least 6 carbon atoms,
R "represents a monovalent hydrocarbon group or hydrocarbon oxy group, a halogenated hydrocarbon group or hydrocarbon oxy group, or a hydrocarbon group or hydrocarbon oxy group containing oxygen in the form of an ether bond or a hydroxyl group. , R ″ contains an epoxy group, c is 0, 1, 2 or 3.
x, y and z are at least 1, and when c is 0, z
Is at least 2. ) Organosilicon compounds,
And (E) a storage-stable elastomer molding composition containing a metal compound selected from the group consisting of aluminum acetylacetonate, iron acetylacetonate, zinc acetylacetonate, and aluminum salts of fatty acids. An object is provided from the first part and the second part, and the component (C) is present only in the first part of the composition,
And the component (D) is present only in the second part of the composition.