JPH0940932A - Adhesive primer - Google Patents

Abstract

(57) Abstract: Lamination of new uncured addition-polymerized silicone, especially room temperature-curable silicone, on addition-cured silicone cured product that has not been sufficiently adhered without treatment, and has been deteriorated by water absorption and oil absorption. A bonding primer and a bonding method used for carrying out the bonding with a sufficient bonding force. The present invention provides a primer for adhering an addition polymerization cured product, wherein a platinum catalyst for addition polymerization curing is dissolved in an organic solvent when the addition polymerization silicone is further laminated on the addition polymerization cured silicone. Is applied, and then uncured addition-polymerized silicone is laminated and cured to firmly bond.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an adhesive primer for adhering an uncured addition-polymerized silicone to a cured addition-polymerized silicone.

[0002]

2. Description of the Related Art When adding addition-polymerized silicone to cured addition-polymerized silicone, for example, it is added to a rubber plate used for a vibration-proof material or added to a soft lining material attached to a denture. In some cases, it may be necessary to add an uncured addition-polymerized silicone to be newly cured to the cured addition-polymerized silicone by, for example, mounting.

[0003]

When adding an uncured silicone to be newly cured to a cured addition-polymerized silicone, especially when it is deteriorated by water absorption, oil absorption, etc., simply the uncured silicone is simply added. However, there is a problem in that the silicone rubber that has been newly placed on the original silicone rubber, particularly room temperature curable silicone, does not adhere sufficiently even if it is placed. Therefore, in such a case, it is necessary to remake all of the silicone rubber into the desired shape, and in the case of a soft dental backing material, remove all the old backing material and then add a new backing material. There are problems that it is troublesome to operate, such as having to wear it, and that it is economically disadvantageous.

[0004]

Means for Solving the Problems As a result of intensive studies to solve the above-mentioned problems of the prior art, the present inventors have found that an adhesion primer made of an organic solvent solution of a platinum-based catalyst for curing an addition polymerization silicone is added with an addition polymerization silicone. It is applied in advance on the part to be newly added of the cured product, and uncured addition-polymerization cured silicone is placed on that part and cured to bond the newly added silicone to the original cured silicone with sufficient strength. After finding out the above, the present invention has been completed.

That is, the present invention is a primer for adhering an addition-polymerized silicone cured product, characterized in that a platinum-based catalyst for curing an addition-polymerized silicone is dissolved in an organic solvent.

Another invention is a method for adhering an addition-polymerized silicone, which comprises applying the above-mentioned primer for adhering an addition-polymerized silicone cured product to a cured addition-polymerized silicone, and then laminating and curing an uncured addition-polymerized silicone. Is.

As the platinum catalyst for curing the addition polymerization silicone used in the present invention, any catalyst can be used as long as it is used in a usual hydrosilylation reaction. For example, chloroplatinic acid, its alcohol modified product, platinum. The vinyl siloxane complex and the like can be mentioned. In order to enhance the storage stability, a material having a small amount of chloro, such as a vinyl siloxane complex of platinum, is preferable. Specifically, as described in JP-B-47-23679,
Platinum tetravinylsilane, 1,3-divinyltetramethyldisiloxane, or 1,3,5,7-tetravinyl-1,3,5,7-tetramethylcyclotetrasiloxane complex, chloroplatinic acid and octyl Examples include reaction products with alcohol.

[0008] The amount of the platinum-based catalyst compounded is 10 ppm to 1000 in terms of platinum in the entire solution as the adhesive primer.
It may be 0 ppm, preferably 100 ppm to 5000 ppm. When the content is 10 ppm or less, the progress of the hydrosilylation reaction at the adhesive interface becomes insufficient, and it becomes difficult to exert a sufficient effect as a primer for adhesion, and even if it is added in an amount of 10,000 ppm or more, a further adhesive effect is obtained. Not only is not economically disadvantageous, but it is also disadvantageous in storage stability such as precipitation of platinum black.

The organic solvent for forming the platinum-based catalyst solution can be used without any limitation as long as it is an organic solvent capable of dissolving the platinum-based catalyst, but it may be used at room temperature because of the residual solvent on the adhesive interface. Those having volatility are preferable.

Specific examples of the organic solvent include silicone oil, toluene, methylene chloride, acetone, alcohols such as methanol and ethanol, petroleum such as hexane, and the like. Due to their volatility and swelling properties to silicone rubber, etc. Methylene chloride, toluene, acetone and the like are preferable.

If desired, the adhesive primer of the present invention may further contain other additives as long as the physical properties thereof are not significantly deteriorated. Such additives include pigments, dyes,
Examples include fragrances, antioxidants, and ultraviolet absorbers.

The addition-polymerized silicone which is bonded by using the bonding primer of the present invention and by the bonding method of the present invention refers to a commonly used addition-polymerized silicone and is not particularly limited. Its general composition is as follows: organopolysiloxane having a terminal unsaturated bond (hereinafter referred to as unsaturated bond-containing polysiloxane) and Si
An organohydrogenpolysiloxane having an H group (hereinafter referred to as SiH siloxane) is used as a matrix, the above-mentioned platinum catalyst is used as a reaction catalyst, and silica powder or silicone resin powder is used as a reinforcing filler.

The unsaturated bond-containing polysiloxane is not particularly limited in structure of other organic groups as long as it is an organopolysiloxane having at least two organic groups having a terminal unsaturated bond in one molecule, and a straight-chain structure. Or may be branched and may be a mixture thereof.

Examples of the organic group having a terminal unsaturated bond include a vinyl group, an allyl group, a 1-butenyl group and the like, but a vinyl group bonded to a silicon atom is most advantageous because of ease of synthesis. . These organic groups having a terminal unsaturated bond may be present at either or both ends of the molecular chain of the organopolysiloxane, or both of them, but the cured elastic body has excellent physical properties. In order to have specific properties, it is preferable that at least one is present at the terminal.

Examples of the organic group bonded to a silicon atom other than the organic group having a terminal unsaturated bond include a methyl group, an ethyl group,
Alkyl groups such as propyl group, butyl group, octyl group, aryl groups such as phenyl group, chloromethyl group, 3,
Substituted alkyl groups such as a 3,3-trifluoropropyl group are exemplified, and among these, a methyl group is most preferable from the viewpoints of easy synthesis and keeping good physical properties after curing.

Further, it has suitable properties as a rubber elastic material, in particular, has an appropriate hardness after curing and has a sufficient elongation,
In order to obtain mechanical strength, 50 units of siloxane units composed only of organic groups having no terminal unsaturated bond are provided between siloxane units composed of organic groups having terminal unsaturated bonds.
It is preferable that 5,000 to 5,000, particularly 100 to 2,000, are continuously contained. When the number of siloxane units having only an organic group having no terminal unsaturated bond is less than 50, it is difficult to obtain sufficient elongation, elasticity and mechanical strength after curing. If the number of siloxane units having only organic groups having no terminal unsaturated bond exceeds 5000, not only the viscosity becomes so high that the operability before curing is impaired, but also it becomes difficult to obtain sufficient hardness after curing. It is in.

Typical examples of the unsaturated bond-containing polysiloxane used in the present invention are as follows.

[0018]

Embedded image

(However, Ph represents a phenyl group) and the like. In addition, the bonding order of each repeating structural unit in the compounds used in the compounds and Examples and Comparative Examples described later is completely arbitrary, and the number of repeating structural units shown in the structural formula is simply the total amount of each structural unit. It only shows the average.

SiH siloxane is a component having a function of cross-linking the unsaturated bond-containing polysiloxane to form a rubber elastic body. To react with the unsaturated bond-containing polysiloxane to form a crosslinked structure, at least three hydrogen atoms bonded to silicon atoms are required. If the number is less than 3, a crosslinked structure is not obtained and a rubber elastic body cannot be obtained.

Examples of the organic group bonded to a silicon atom other than a hydrogen atom include those similar to the organic group having no terminal unsaturated bond in the unsaturated bond-containing polysiloxane described above, but the synthesis is easy. In addition, the methyl group is most preferable from the viewpoint of maintaining good physical properties after curing. Such SiH siloxane may be linear, branched, or cyclic, and may be a mixture thereof.

Typical examples of the SiH siloxane used in the present invention are shown below.

[0023]

Embedded image

And the like. Also in the SiH siloxane used in Examples and Comparative Examples described above and below,
Like the unsaturated bond-containing polysiloxane, the bonding order of the repeating structural units in the molecule is completely arbitrary.

The blending amount of each of the unsaturated bond-containing polysiloxane and the SiH siloxane in the present invention varies greatly depending on the molecular weight thereof. Normally, one unsaturated bond in the unsaturated bond-containing polysiloxane is contained in the SiH siloxane. 0.5 or more, preferably 1 hydrogen atom bonded to the silicon atom of
It suffices to mix them in a ratio of up to 5. If this ratio is too small, the curability becomes insufficient, and if it is too large, the resulting elastic body becomes brittle or excess hydrogen atoms bonded to silicon atoms remain, so that the temporal stability of the elastic body tends to decrease. is there.

Typical examples of silica-based powders and silicone resin powders used as reinforcing fillers are as follows:
Examples include pulverized quartz, fused silica, wet silica, dry silica, and polyorganosilsesquioxane fine particles. In addition to these, if necessary, polytetrafluoroethylene, fluorocarbon resin powder such as povinylidene fluoride, carbon black, inorganic filler such as glass fiber, polymethylmethacrylate, organic filler such as polydimethylsiloxane and composite filler ( (A pulverized composite of an inorganic oxide and a polymer) and the like.

Further, other additives may be added to the extent that the physical properties thereof are not significantly deteriorated. Examples of such additives include reaction inhibitors, ultraviolet absorbers, plasticizers, pigments, antioxidants, antibacterial agents, and the like.

The addition-polymerized silicone cured product, which is the adherend to be treated with the adhesive primer of the present invention, is
It means a cured product obtained by curing the above addition-polymerized silicone by the action of a platinum-based catalyst.

By the way, even if a new uncured addition-polymerized silicone is placed on the above-mentioned addition-polymerized silicone cured product and cured to add it, especially when the addition-polymerized silicone cured product is deteriorated by water absorption or oil absorption, If the addition-polymerized silicone to be added is one that is curable at room temperature, it hardly adheres. However, the adhesive primer of the present invention is pre-applied on the surface of the addition-polymerized silicone cured product surface where new silicone is to be added, and then the uncured addition-polymerized silicone is applied and cured to provide sufficient strength. Can be bonded.

[0030]

EFFECT OF THE INVENTION The primer for adhering an addition-polymerized silicone cured product obtained according to the present invention is newly added to a cured addition-polymerized silicone even when its surface is deteriorated by water absorption, oil absorption or the like. Even added addition-polymerized silicones, especially those that cure at room temperature, can be firmly bonded. As a result, there is no need to remake everything, and not only operability but also economic efficiency can be improved.

[0031]

EXAMPLES The present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

Table 1 shows the structures and abbreviations of the materials used in this example and comparative examples.

[Adhesion Test Method] An addition silicone paste having a composition shown in Table 2 was prepared as an adherend to be tested, and the mixture was kneaded and cured at a kneading ratio shown in the curing conditions in the table. It was dipped in and absorbed with water or oil (adhesion test body). The adhered surface of the adherend test piece is thoroughly washed, the adhesion primer solution is applied, and the kneaded uncured addition-polymerized silicone (adhesion test piece) is applied and cured. After curing, it was attempted to be peeled off from the adhesive interface with a spatula, and evaluation was made by observing the state of destruction.

[0034]

[Table 1]

[0035]

[Table 2]

Example 1 Silicone A shown in Table 2 was cured and stored in edible oil for 1 month. The surface of the cured product was washed with a neutral detergent and then polished with water-resistant abrasive paper. An ethanol solution of chloroplatinic acid (platinum content 1000 pp
m) is applied, and silicone A kneaded at a predetermined kneading ratio is applied onto the m), and allowed to stand in the air for about 10 minutes to cure. After curing, an attempt was made to peel it from the adhesive interface with a spatula, and the state of the fracture was observed.

Examples 2 to 5, Comparative Examples 1 and 2 Adhesion test pieces, adhesion primers, and adhesion test pieces were selected from the combinations shown in Table 3, cured and laminated according to Example 1, and the adhesion test was conducted. went. The results are also shown in Table 3.

Example 6 A commercially available soft lining material A (Tokuyama Soft Relining, manufactured by Tokuyama Corporation) was cured according to the manufacturer's method (discharging mixing chips, leaving still in air for 20 minutes), and the cured product was used as edible oil. It was soaked in 1 month. After immersion, wash well, polish the surface to expose the fresh surface, apply methylene chloride solution of platinum vinyl siloxane complex containing 500 ppm of platinum as an adhesion primer to the polished surface, and further paste on it to cure. (Immersion in 35 ° C. water for 5 minutes: retention in the oral cavity for 5 minutes was reproduced) and an adhesion test was performed. The results are shown in Table 3.

Comparative Example 3 The same test as in Example 6 was conducted except that methylene chloride was used as the adhesion primer. The results are shown in Table 3.

[0040]

[Table 3]

Claims (2)

[Claims] 1. A primer for adhering an addition-polymerized silicone cured product, comprising a platinum-based catalyst for curing an addition-polymerized silicone dissolved in an organic solvent. 2. Adhesion of addition-polymerized silicone characterized in that the addition-polymerized silicone cured product is coated with the primer for adhering addition-cured silicone cured product according to claim 1, and then uncured addition-polymerized silicone is laminated and cured. Method.