JP3808279B2 - Bonding method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to an adhesion method, and more specifically, a method for adhering a silicone rubber layer to a cured silicone rubber containing a platinum-based catalyst, and a cured silicone rubber containing a platinum-based catalyst using the adhesion method and the silicone rubber layer. To adhere to adherends such as glass, plastic, metal, wood, carbon, etc.The present invention relates to an adhesion method.
[0002]
[Prior art]
Conventionally, addition-curable adhesive liquid silicone rubbers and condensation-curable adhesive liquid silicone rubbers have been widely used for sealing agents, various adhesives, paints, and the like.
[0003]
These adhesive liquid silicone rubbers usually develop a desired adhesive force while being cured by heating or long-term curing at room temperature.
[0004]
[Problems to be solved by the invention]
However, the cured addition-curable silicone rubber has a problem that sufficient adhesive force cannot be obtained even if addition-curable adhesive liquid silicone rubber or condensation-curable adhesive liquid silicone rubber is used.
[0005]
Furthermore, since the adhesive liquid silicone rubber is a fluid viscous material, a method of filling a container such as a tube or a cartridge is used. For this reason, tools such as a cartridge gun and masking tape are required for the bonding work, and in some cases, a device for mixing and defoaming is further required at the bonding site, which makes it impossible to bond by simple manual work. is there.
[0006]
In general, addition curable silicone rubbers are no longer reactive once cured, so that the addition curable silicone rubber cured product can be further bonded to the adherend with respect to the addition curable silicone rubber cured product. It is necessary to modify the surface of this, which has the problem of increasing labor and cost.
[0007]
Furthermore, since the cured portion of the addition-curing type silicone rubber cannot be repaired even if it is damaged, there is a problem that the entire silicone rubber molded product must be replaced with a new one.
[0008]
The present invention has been made to solve the above problems.
[0009]
  That is, the present invention can adhere to an addition-curable silicone rubber cured product, that is, a cured silicone rubber containing a platinum-based catalyst.Bonding methodThe purpose is to provide.
[0010]
[Means for Solving the Problems]
  The bonding method of the present invention comprises:Evenly mixedA polyorganoorganism which is substantially linear having a vinyl group bonded to a silicon atom in the molecule as the first component on the surface of the first layer made of a silicone cured product containing a platinum-based catalyst and having a polymerization degree of 1000 to 20000. Uncured, which is a polyorganosiloxane composition having a siloxane and a polyorganosiloxane having a hydrogen atom bonded to two or more silicon atoms on average in the molecule as the second component and having a plasticity of 80 to 1500 A step of applying the adhesive putty formed of the polyorganosiloxane composition to a sheet or string having a thickness of 0.05 mm to 10 mm to form a second layer, and standing in an environment of 20 to 30 ° C. or 30 And a step of bonding the first layer to the first layer while curing the second layer by heating to a temperature equal to or higher than C.
[0011]
  In addition, the other bonding method of the present invention is:Evenly mixedA polyorganoorganism which is substantially linear having a vinyl group bonded to a silicon atom in the molecule as the first component on the surface of the first layer made of a silicone cured product containing a platinum-based catalyst and having a polymerization degree of 1000 to 20000. Uncured, which is a polyorganosiloxane composition having a siloxane and a polyorganosiloxane having a hydrogen atom bonded to two or more silicon atoms on average in the molecule as the second component, and having a plasticity of 80 to 1500 A step of forming a second layer by applying an adhesive putty formed of the polyorganosiloxane composition to a sheet or string having a thickness of 0.05 mm to 10 mm; and glass, plastic on the second layer Laminating a third layer formed of one material selected from the group consisting of carbon, metal, wood and carbon, and leaving it in an environment of 20 to 30 ° C. A step of heating to 30 ° C. or higher to adhere to the first layer and the third layer while curing the second layer comprises a.
[0012]
In the bonding method, examples of the bonding putty include the following compositions.
[0013]
That is, the composition is, as the first component, a polyorganosiloxane having a linear group having a vinyl group bonded to a silicon atom in the molecule and having a polymerization degree of 1000 to 20000,
And the second component includes polyorganohydrogensiloxane having hydrogen atoms bonded to an average of more than two silicon atoms in the molecule,
It is a polyorganosiloxane composition having a plasticity of 80 to 1500.
[0014]
The first component preferably has two or more vinyl groups bonded to silicon atoms in one molecule.
[0015]
In the bonding method of the present invention, the surface of the cured silicone rubber containing a platinum-based catalyst is:
As a first component, a polyorganosiloxane having a vinyl group bonded to a silicon atom in the molecule, which is substantially linear and has a polymerization degree of 1000 to 20000,
And the second component includes polyorganohydrogensiloxane having hydrogen atoms bonded to two or more silicon atoms on average in the molecule,
After applying an adhesive putty made of a polyorganosiloxane composition having a plasticity of 80-1500, it is allowed to cure at room temperature (20-30 ° C.). Or you may heat to 30 degreeC or more.
[0016]
For this reason, it has become possible to bond to an addition-curable silicone cured product that has been recognized as impossible. In addition, according to the method of the present invention, only an adhesive putty may be bonded to an addition-curable silicone rubber cured product, that is, a silicone rubber cured product containing a platinum-based catalyst, and further, glass, plastic, metal, wood Alternatively, an adherend such as carbon may be placed and bonded.
[0017]
It is considered that the adhesion mechanism according to the method of the present invention is performed as follows.
[0018]
By placing an adhesive putty on a silicone rubber cured product containing a platinum catalyst, the platinum-based catalyst in the cured product also acts on the adhesive putty, so that the adhesive putty cures while adhering to the silicone rubber cured product. Think.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the bonding method according to the embodiment of the present invention will be described.
[0020]
The one-component vinyl group-containing polydiorganosiloxane used for the adhesive putty used in the present invention is a component that becomes the base polymer of the polyorganosiloxane composition used in the present invention.
[0021]
The first component is crosslinked by addition reaction to form a network molecule, and in order to form an elastic adhesive layer, it has two or more vinyl groups bonded to silicon atoms in one molecule and forms a plastic adhesive layer. In some cases, it has one or more vinyl groups per molecule and less than two on average. Except when a low hardness is required, the first component absorbs stress by forming an elastic adhesive layer with excellent mechanical strength that takes advantage of the characteristics of silicone rubber. preferable.
[0022]
The vinyl group may be present in the siloxane unit at the molecular chain terminal of the first component or in the intermediate siloxane unit. However, in order to obtain an elastic adhesive layer having excellent mechanical strength, the vinyl group It is preferable that at least a part is present in the siloxane units at both terminals.
[0023]
The siloxane skeleton of the first component is substantially linear and may have some branching or three-dimensional structure. The polymerization degree of the first component, that is, the number of siloxane units is 1,000 to 20,000, preferably 3,000 to 10,000, and more preferably 5,000 to 8,000. This is because if the degree of polymerization is less than 1,000, the composition has stickiness and fluidity, and the workability as an adhesive is inferior. On the other hand, those having a degree of polymerization exceeding 20,000 are not only difficult to synthesize, but also difficult to mix with fillers.
[0024]
Examples of the organic group other than the vinyl group bonded to the silicon atom of the first component include linear or branched alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, hexyl, octyl, decyl, and dodecyl; cyclohexyl Aryl groups such as phenyl, tolyl and xylyl: aralkyl groups such as 2-phenylethyl and 2-phenylpropyl; monovalent groups such as chloromethyl, chlorophenyl and 3,3,3-trifluoropropyl And the substituted hydrocarbon group. Among these, since the advantages of the silicone adhesive such as heat resistance, cold resistance, and weather resistance can be satisfactorily exhibited, 92 mol% or more is preferably a methyl group, and substantially all may be a methyl group. Other groups such as a phenyl group can be used in combination as required depending on the required properties, such as a phenyl group when cold resistance is required for the adhesive, and a 3,3,3-trifluoropropyl group when oil resistance is required.
[0025]
The molecular chain terminal of the first component is preferably a triorganosiloxane unit in which only a substituted or unsubstituted monovalent hydrocarbon group is bonded to a silicon atom. As such a siloxane unit, a trimethylsiloxane unit, dimethylphenyl Examples that do not contain vinyl groups such as siloxane units and methyldiphenylsiloxane units; and preferably those that contain vinyl groups such as dimethylvinylsiloxane units and methylphenylvinylsiloxane units. An alkoxy group such as
[0026]
The polyorganohydrogensiloxane of the second component used in the present invention functions as a crosslinking agent of the first component by the addition reaction of the hydrosilyl group contained in the molecule to the vinyl group in the first component. In order to form a cured product having a network structure, each molecule has an average of more than two hydrogen atoms bonded to silicon atoms, particularly excellent adhesion, and excellent mechanical properties upon curing. In order to obtain an elastic adhesive layer having, it is preferable to have at least three hydrogen atoms.
[0027]
Examples of the organic group bonded to the silicon atom of the siloxane unit include those similar to the organic group other than the vinyl group in the first component described above, and among them, the point of easy synthesis and the compatibility with the first component Therefore, a methyl group is most preferable.
[0028]
The siloxane skeleton of the second component may be linear, branched or cyclic. Moreover, you may use these mixtures. The degree of polymerization of the second component is not particularly limited, but is preferably in the range of 10 to 200 because synthesis is easy and does not volatilize during storage or when the oxidation reaction is performed by heating.
[0029]
As a specific example of the second component, (1) at least a unit having a molecular end blocked with a triorganosiloxane unit such as a trimethylsiloxane unit and having a hydrosilyl group such as a methylhydrogensiloxane unit in the middle is included in the molecule. 3 linear polyorganohydrogensiloxanes; and (2) molecular ends blocked with siloxane units having a hydrosilyl group such as dimethylhydrogensiloxane units, and hydrosilyl groups such as methylhydrogensiloxane units in the middle. And a linear polyorganohydrogensiloxane having at least one unit having the above in the molecule. In (1) and (2), a unit that does not contain a hydrosilyl group, such as a dimethylsiloxane unit, may or may not exist. As another specific example of the second component, (3) a monofunctional unit having a hydrosilyl group such as a dimethylhydrogensiloxane unit and a tetrafunctional SiO₂Examples thereof include branched polyorganohydrogensiloxane composed of units.
[0030]
In the present invention, the polyorganosiloxane composition used for forming the adhesive layer contains the first component and the second component described above. In the composition, the ratio between the vinyl group in the first component and the hydrogen atom bonded to the silicon atom in the second component is fairly wide, for example, the number of hydrogen atoms is 0 for one vinyl group. .1 to 100 can be set. The compounding amount of the second component with respect to the first component varies depending on the vinyl group content of the first component and the hydrosilyl group content of the second component, but the second component is usually 0 with respect to 100 parts by weight of the first component. 0.1 to 50 parts by weight, preferably 0.2 to 20 parts by weight. If the second component exceeds 50 parts by weight, sufficient physical properties cannot be imparted to the adhesive layer.
[0031]
The polyorganosiloxane composition used in the present invention contains the above-mentioned first component and second component, and if necessary, a filler, an adhesion-imparting agent, a heat resistance improver, a flame retardant, etc. Can be blended. In this system, a curing reaction catalyst is stored separately, so that it is not necessary to add a curing inhibitor. However, when this is used, care must be taken because it may inhibit the expression of adhesiveness. .
[0032]
The filler is used to give the polyorganosiloxane composition an appropriate plasticity and workability, and to give the cured adhesive layer the necessary mechanical properties, and has a reinforcing and / or non-reinforcing property. Fillers can be included. In order to obtain an adhesive having good workability, at least a part of the filler is preferably a silica-based filler having a particle size of 20 μm or less.
[0033]
Examples of the reinforcing filler include fine silica powders such as fumed silica, silica aerogel, and precipitated silica, which may be used as they are or may be treated with an organosilicon compound to make the surface hydrophobic. Examples of the organosilicon compound used for the surface treatment include dimethyldichlorosilane, trimethylchlorosilane, hexamethyldisilazane, octamethylcyclotetrasiloxane, and the like. Since the workability of the composition is excellent, hexamethyldisilazane is Particularly preferred. The treatment is carried out by adsorbing the organosilicon compound used for the treatment on the surface of the silica fine powder at room temperature or high temperature in a gas phase or a liquid phase using an inert solvent such as n-hexane, and heat-treating the silica. This can be done by organosilylating the silanol group on the surface of the fine powder. Further, in the step of kneading the reinforcing filler with the first component, the treatment may be performed by heating and kneading together with an organosilicon compound such as hexamethyldisilazane.
[0034]
Non-reinforcing fillers include diatomaceous earth, silica such as pulverized quartz, titanium oxide, alumina, magnesium oxide, zinc oxide, calcium carbonate, carbon black and the like.
[0035]
Although the compounding quantity of a filler is not specifically limited, 5-500 weight part is preferable with respect to 100 weight part of 1st components, and 10-400 weight part is further more preferable. If it is less than 5 parts by weight, the composition becomes sticky and the workability is poor, and if it exceeds 500 parts by weight, the plasticity increases and the workability is also poor, and the cured adhesive layer has good mechanical strength. And rubber elasticity is not obtained.
[0036]
Adhesive agents include epoxy groups such as 3-glycidoxypropyl, 2- (3,4-epoxycyclohexyl) ethyl, vinyl, 3-methacryloxypropyl, 3-acryloxypropyl or olefinic double bonds A silane having a substituted or unsubstituted alkoxy group such as methoxy, ethoxy, 2-methoxyethoxy and / or a hydrogen atom having at least one carbon functional group selected from the group having Siloxane is used. Further, as other adhesion-imparting agents, silicon functional isocyanurates having a substituted or unsubstituted alkoxy group such as methoxy, ethoxy, propoxy, and 2-methoxyethoxy bonded to a silicon atom are also used.
[0037]
Examples of such adhesion imparting agents include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropyl (methyl) dimethoxysilane, and 2- (3,4-epoxy. Epoxy group-containing silanes such as (cyclohexyl) ethyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltriethoxysilane, 2- (3,4-epoxycyclohexyl) ethyl (methyl) dimethoxysilane and their partial hydrolysis Decomposition condensates; (meth) acrylic group-containing silanes such as 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-methacryloxypropyl (methyl) dimethoxysilane and their partial hydrolysis condensation Product; pinyltrimethoxy Vinyl group-containing silanes such as vinyltriethoxysilane, vinyltris (2-methoxyethoxy) silane, and partial hydrolysis condensates thereof; 3-glycidoxypropyl group-containing methylhydrogen cyclic tetrasiloxane, 3-methacryloxy Propyl group-containing methylhydrogen cyclic tetrasiloxane, 3-glycidoxypropyl group-containing methylmethoxy cyclic siloxane, 3-glycidoxypropyl group and 2- (trimethoxysilyl) ethyl group-containing methylhydrogen cyclic siloxane, 3- Methyl hydrogen cyclic siloxane having methacryloxypropyl group and 2- (trimethoxysilyl) ethyl group, such as methyl hydrogen cyclic siloxane containing 2-[(3-trimethoxysilyl) propyloxycarbonyl] propyl group Cyclic siloxane; such as methyl siloxane having 3-glycidoxypropyl group, methylhydrogensiloxane having 3-glycidoxy group and vinyl group, methylsiloxane having 3-glycidoxy group and 2- (trimethoxysilyl) ethyl group Examples include chain siloxanes; cyanuric ring-containing organosilicon compounds such as tris (3-trimethoxysilylpropyl) isocyanurate.
[0038]
The polyorganosiloxane composition has a plasticity measured by a plasticity test described in JIS K6300 at 25 ° C. of 80 to 1,500, preferably 100 to 1,000. If the plasticity is less than 80, it is too soft and the workability is poor, and if it exceeds 1,500, it becomes too hard and the adhesion to the adherend is lowered.
[0039]
In the present invention, such a polyorganosiloxane composition is used as an adhesive putty. The shape of the adhesive putty may be any shape as long as it is suitable for bonding silicone rubber cured products. However, since it is easy to perform preforming by dispensing or extruding, it is sheet-like, tape-like Or a string shape is preferable. In the case of a sheet or tape, the thickness is preferably 10 mm or less, and more preferably 0.01 to 2 mm when used for adhesion. If the thickness exceeds 10 mm, curing of the central portion may be insufficient.
[0040]
Also in the case of a string, for the same reason, the diameter is preferably 10 mm or less, and preferably 0.01 to 2 mm.
[0041]
Such an adhesive putty is prepared, for example, by uniformly mixing the first component, the second component and other components blended as necessary by a mixing means such as a two-roller or a kneader. For example, it can be produced by separating from a calender roll or two rolls, or by extrusion with an extruder.
[0042]
The kneading and preforming can be performed at room temperature, and may be performed, for example, by heating to a temperature of 50 to 200 ° C. as necessary.
[0043]
Next, a cured silicone rubber containing a platinum catalyst will be described.
[0044]
The platinum content of the cured silicone rubber containing a platinum-based catalyst is 0.1 to 1000 ppm, preferably 1 to 200 ppm. If this amount is less than 0.1 ppm, curing of the adhesive putty will not proceed. If it exceeds 1000 ppm, not only will there be no effect matching the blending amount, but it will be economically disadvantageous.
[0045]
Platinum-based catalysts are chloroplatinic acid, complex mixtures obtained by heating chloroplatinic acid and alcohol, platinum compounds such as platinum-olefin complexes, platinum-vinylsiloxane complexes, platinum-triphenylphosphine complexes, palladium-phosphine complexes. Examples thereof include palladium compounds such as those described above, rhodium compounds such as rhodium-phosphine complexes, and those in which platinum or palladium is supported on a carrier such as alumina, silica, and carbon.
[0046]
Furthermore, the curing method of the silicone cured product containing the platinum-based catalyst is most desirably the addition curing type, but the effect is also exhibited in the organic peroxide curing type.
[0047]
Furthermore, a method for bonding to a cured silicone rubber using this adhesive putty will be described.
[0048]
An integrated keyboard top for a personal computer will be described as an example of the cured silicone rubber.
[0049]
First, in the following manner, 100 parts of a dimethylsiloxane polymer having both ends blocked with dimethylvinylsilyl groups and a viscosity at 25 ° C. of 10,000 centipoise, a specific surface area of 300 cm²40 parts of fumed silica, 8 parts of hexamethyldisilazane, and 1 part of water were charged in a kneader, stirred at room temperature for 1 hour, heated to 150 ° C., and mixed with heat for 2 hours. Thereafter, the mixture was cooled to room temperature, to which was further added 20 parts of a dimethylsiloxane polymer having both ends blocked with dimethylvinylsilyl groups and a viscosity at 25 ° C. of 10,000 centipoise, and a viscosity at 25 ° C. of 10 centipoise. 3 parts of a certain methyl hydrogen polysiloxane and 5 parts by mole of vinyl groups directly bonded to silicon atoms, 4 parts of vinyl methyl polysiloxane having a viscosity of 1000 centipoise at 25 ° C., extending the time to cure at room temperature For this purpose, 0.1 part of acetylene alcohol and 100 ppm of platinum-vinylsiloxane complex were added and mixed well until uniform.
[0050]
The obtained uncured silicone rubber composition was put in a mold, and the temperature was 170 ° C. and the pressure was 100 kg / cm.²Press vulcanize for 10 minutes, demold, and then heat vulcanize for 4 hours in an oven at 200 ° C. to obtain a silicone rubber keyboard with a length of 280 mm, a width of 100 mm, a height of 10 mm, and a thickness of 2 mm. Molded.
[0051]
Next, a method in which a film-like adhesive putty prepared to a thickness of 200 μm is cured and bonded to the integrally formed keyboard top as a cured silicone rubber obtained as described above will be described.
[0052]
1 and 2 are vertical sectional views of an integrally molded keyboard top 1 for carrying out the bonding method of the present invention, and FIG. 3 is a flowchart illustrating the procedure of the bonding method of the present invention.
[0053]
Now, the above-mentioned film-like adhesive putty 2 is arranged on the surface 1 a of the integrally molded keyboard top 1. (FIG. 1 / Step 1).
[0054]
Next, the keyboard top 1 on which the adhesive putty 2 is arranged is left to stand at room temperature (25 ° C.) for 12 hours (FIG. 2 / step 2), and the adhesive putty is cured and bonded to the keyboard top.
[0055]
The laminated body thus obtained has a two-layer structure in which the keyboard top 1 as the cured silicone rubber and the adhesive putty 2 are arranged directly adjacent to each other, and there is no intermediate layer such as an adhesive layer.
[0056]
As described above in detail, according to the bonding method of the present invention, the silicone rubber cured product containing a platinum-based catalyst has a vinyl group bonded to a silicon atom in the molecule as the first component. A polyorganosiloxane that is linear and has a degree of polymerization of 1000 to 20000, and, as a second component, includes a polyorganohydrogensiloxane having hydrogen atoms bonded to an average of more than two silicon atoms in the molecule, An adhesive putty made of a polyorganosiloxane composition having a plasticity of 80 to 1500 is placed, and then the cured silicone rubber and the adhesive putty are cured and bonded, so that the adhesive putty is directly bonded to the surface of the cured silicone rubber. The This is presumably because the platinum component in the silicone cured product acts on the adhesive putty side to extract the adhesive action.
[0057]
In addition, this invention is not limited to the range of the said embodiment. For example, in the above embodiment, a film-like adhesive putty is disposed on the silicone rubber to form a two-layer structure in which the cured silicone rubber and the adhesive putty are bonded. It is sandwiched between adherends of metal, wood, carbon, etc., and then left at room temperature (20-30 ° C.) or heated to an appropriate temperature, for example, 30 ° C. or more, to cure the adherend with silicone rubber. It is also possible to adhere to an object. In this case, a laminate including a three-layer structure of a cured silicone, an adhesive putty, and an adherend is formed.
[0058]
The adhesive putty used in this embodiment can also be used for an insulating material called HVI (High Voltage Insulator).
[0059]
(Example 1)
Embodiment 1 of the present invention will be described below.
[0060]
Millable silicone rubber was cured at the following ratio.
Millable silicone rubber (A-1) 100 parts by weight
Organic peroxide curing agent (TC-8; manufactured by GE Toshiba Silicone Co., Ltd.) 0.5 parts by weight
Chloroplatinic acid solution 0.5 parts by weight
The platinum content of A-1 after blending was 85 ppm.
[0061]
The cured product is placed in a mold cavity having a length of 80 mm × width of 25 mm × thickness of 2 mm, pressed under conditions of 170 ° C. × 10 minutes, demolded, and then placed in an oven at 200 ° C. for 4 hours. Heat vulcanization was performed to produce a test product.
[0062]
On the other hand, an adhesive putty composition was blended by the following method.
[0063]
Both ends are blocked with dimethylvinylsilyl groups, and a specific surface area of 300 m is added to 100 parts by weight of a polydiorganosiloxane having a polymerization degree of 6000 and comprising 99.8 mol% of dimethylsiloxane units and 0.2 mol% of methylvinylsiloxane units.²/ G of fumed silica 60 parts by weight, hexamethyldisilazane 12 parts by weight, and water 6 parts by weight are kneaded at room temperature for 1 hour by a kneader to trimethylsilylate the silica surface, and then the temperature is 150. The resulting mixture was kneaded for 2 hours, and the resulting decomposition residue was removed.
[0064]
Thereafter, the temperature is lowered to room temperature, 5 parts by weight of polyhydrogensiloxane having a polymerization degree of 50, in which both ends are blocked with a trimethylsilyl group and an intermediate unit is composed of a methylhydrogensiloxane unit, is kneaded to form an adhesive putty. Obtained.
[0065]
Using the above composition, an adhesive putty was formed into a shape of 20 mm long × 25 mm wide × 0.4 mm thick, and the two test specimens were bonded together via this adhesive putty to prepare a test piece for a shear tensile test. Created. FIG. 4 is a sectional view of the completed test piece.
[0066]
When left for 24 hours in an environment of 25 ° C. and a relative humidity of 40%, the adhesive putty was cured and adhered to the A-1 test product.
[0067]
A shear tensile test was performed on the test piece that had been bonded.
[0068]
About the shear tension test, it tested by 10 mm / min with the tension | pulling speed using Shimadzu Corporation autograph AG1000D. As a result, A-1 broke. The tensile strength at break was 5 Ma.
[0069]
(Comparative Example 1)
Hereinafter, Comparative Example 1 of the present invention will be described.
[0070]
Millable silicone rubber was cured at the following ratio.
Millable silicone rubber (A-1) 100 parts by weight
Organic peroxide curing agent (TC-8; manufactured by GE Toshiba Silicone Co., Ltd.) 0.5 parts by weight
Chloroplatinic acid solution 0.5 parts by weight
The platinum content of A-1 after blending was 85 ppm.
[0071]
The cured product is placed in a mold cavity having a length of 80 mm × width of 25 mm × thickness of 2 mm, pressed under conditions of 170 ° C. × 10 minutes, demolded, and then placed in an oven at 200 ° C. for 4 hours. Heat vulcanization was performed to produce a test product.
[0072]
For the above test specimen, 0.5 parts by weight of organic peroxide curing agent (TC-8) is blended with millable silicone rubber (B-1) manufactured by GE Toshiba Silicone Co., Ltd. X The thickness was adjusted to 0.4 mm, and the two specimens were bonded together to prepare a test piece for a shear tensile test.
[0073]
FIG. 4 is a sectional view of the completed test piece. This test piece was placed in an environment of 170 ° C. for 30 minutes to cure B-1.
[0074]
When the test piece was pulled after curing, the A-1 layer and the B-1 layer were easily separated.
[0075]
(Example 2)
Embodiment 2 of the present invention will be described below.
[0076]
Addition-curable liquid silicone rubber (LIM) for injection molding was cured by the following method.
50 parts by weight of addition-curable liquid silicone rubber for injection molding (agent A)
50 parts by weight of addition-curing liquid silicone rubber for injection molding (agent B)
After mixing 1: 1 liquid silicone rubber A agent and B agent for injection molding, a keyboard was molded under conditions of 170 ° C. × 3 minutes using an injection molding machine manufactured by Aburg.
[0077]
The liquid silicone rubber A for injection molding contained a platinum-based catalyst, and the platinum content of the finished molded product was examined and found to be 100 ppm.
[0078]
On the other hand, 1 part by weight of 3-methacryloxypropyltrimethoxysilane was further added to the adhesive putty formulated in Example 1 to complete an adhesive putty.
[0079]
Using the above composition, an adhesive putty was formed into a shape of 8 mm long × 5 mm wide × 0.2 mm thick, and this adhesive putty was placed on the surface of the keyboard top and further cut into a suitable size. 1. A 1 mm thick PET film was placed and pressure bonded.
[0080]
FIG. 5 is a vertical sectional view showing a state in which a PET film is bonded to the key board top via an adhesive putty.
[0081]
When left for 24 hours in an environment of 25 ° C. and a relative humidity of 60%, the adhesive putty was cured and adhered firmly to the PET film and the LIM.
[0082]
(Comparative Example 2)
Hereinafter, Comparative Example 2 of the present invention will be described.
[0083]
Addition-curable liquid silicone rubber (LIM) for injection molding was cured by the following method.
50 parts by weight of addition-curable liquid silicone rubber for injection molding (agent A)
50 parts by weight of addition-curing liquid silicone rubber for injection molding (agent B)
After mixing 1: 1 liquid silicone rubber A agent and B agent for injection molding, a keyboard was molded under conditions of 170 ° C. × 3 minutes using an injection molding machine manufactured by Aburg.
[0084]
The liquid silicone rubber A for injection molding contained a platinum-based catalyst, and the platinum content of the finished molded product was examined and found to be 100 ppm.
[0085]
A one-component condensation type liquid self-adhesive silicone sealant (C-1) was applied to the keyboard top surface, further cut to an appropriate size, a 0.1 mm thick PET film was placed thereon, and pressure bonded. It was left to stand for 3 days in an atmosphere of room temperature (25 ° C.) × relative humidity (60%).
[0086]
When the adhesion state of the test piece after being allowed to stand was confirmed, the PET film and C-1 were adhered, but TLM 1405 and C-1 were peeled off. Moreover, C-1 was liquid and it was difficult to keep thickness constant.
[0087]
【The invention's effect】
According to the present invention, the adherend can be successfully bonded to the cured silicone rubber.
[Brief description of the drawings]
FIG. 1 is a vertical cross-sectional view of an integrally formed key board top for carrying out the bonding method of the present invention.
FIG. 2 is a vertical cross-sectional view of an integrally formed key board top for carrying out the bonding method of the present invention.
FIG. 3 is a flowchart illustrating the procedure of the bonding method of the present invention.
FIG. 4 is a cross-sectional view of a test piece for a shear tensile test.
FIG. 5 is a vertical sectional view showing a state in which a PET film is bonded to a key board top via an adhesive putty.
[Explanation of symbols]
1. Key board top (cured silicone rubber),
2 …… Adhesive putty.

Claims (4)

On the surface of the first layer made of a silicone cured product containing a uniformly mixed platinum-based catalyst, the first component is substantially linear having a vinyl group bonded to a silicon atom in the molecule, and the degree of polymerization is 1000. A polyorganosiloxane composition having a polyorganosiloxane of ˜20,000 and a polyorganohydrogensiloxane having a hydrogen atom bonded to an average of two or more silicon atoms in the molecule as the second component, and having a plasticity of 80 to 1500 Applying an adhesive putty formed of an uncured polyorganosiloxane composition, which is a product, to a sheet or string of 0.05 mm to 10 mm in thickness to form a second layer;
A step of allowing the second layer to adhere to the first layer while being cured in an environment of 20 to 30 ° C. or being heated to 30 ° C. or higher;
A bonding method comprising:   2. The bonding method according to claim 1, wherein the first component has two or more vinyl groups bonded to silicon atoms in one molecule. It is the adhesion | attachment method of Claim 1 or 2, Comprising: Content of the platinum-type catalyst contained in the said silicone hardened | cured material is 0.1-1000 ppm, The adhesion method characterized by the above-mentioned. On the surface of the first layer made of a silicone cured product containing a homogeneously mixed platinum-based catalyst, the first component is substantially linear having a vinyl group bonded to a silicon atom in the molecule, and the degree of polymerization is 1000. A polyorganosiloxane composition having a polyorganosiloxane having a plasticity of 80 to 1500, comprising a polyorganosiloxane having a plasticity of ˜20,000 and a polyorganohydrogensiloxane having a hydrogen atom bonded to two or more silicon atoms on average in the molecule as the second component Applying an adhesive putty formed of an uncured polyorganosiloxane composition, which is a product, to a sheet or string having a thickness of 0.05 mm to 10 mm to form a second layer;
Laminating a third layer formed of one material selected from the group consisting of glass, plastics, metal, wood, and carbon on the second layer;
Adhering to the first layer and the third layer while curing the second layer by leaving it in an environment of 20-30 ° C. or heating to 30 ° C. or higher;
A bonding method comprising:

Images