JPS61264079A - Production of silicone based adhesive sheet - Google Patents

Abstract

PURPOSE:To obtain an adhesive sheet having uniform adhesive properties readily with certainty, by applying a coating agent consisting of an organopolysiloxane- containing adhesive composition to the surface of a sheetlike material and irradiating the resultant coating film with electron rays at a specific dose. CONSTITUTION:A coating agent consisting of an adhesive composition containing an organopolysiloxane-containing adhesive composition, preferably containing 0.1-20pts.wt. electron polymerizable unsaturated bond-containing monomer, e.g. 1,6-hexanediol diacrylate, in 100pts.wt. organopolysiloxane, preferably a mixture of silicone resin and silicone rubber, to at least one surface of a sheetlike material, preferably a high polymer film such as polyethylene and irradiating the resultant coating film with electron rays at 0.5-20Mrad dose, or 0.1-10Mrad dose in the case of the composition containing electron ray polymerizable unsaturated bond-containing monomer.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention provides a pressure-sensitive adhesive sheet having heat resistance commensurate with the heat resistance of heat-resistant industrial materials such as aluminum foil, polyimide film, and heat-resistant nylon film. , it relates to a method of obtaining it easily and reliably.

[Conventional technology]

The silicone adhesive should not lose its flexibility even in a low-temperature atmosphere of -500C or lower, 2o.

It must be resistant to thermal deterioration and oxidation even in high-temperature environments such as ~250℃, and it must also exhibit excellent electrical properties, chemical resistance, weather resistance, moisture resistance, etc. It has various excellent properties such as exhibiting good adhesion performance against silicone rubber, silicone varnish, Teflon, etc., which are said to have no common adhesives.

However, the silicone adhesive is described in, for example, "Japan Adhesive Association Journal J vol, T9, A9 (1983) p.
P, 36 to l+3, adhesive compositions containing polydimethylsiloxane are coated with, for example, benzoyl peroxide and 2. It is generally produced by adding a peroxide such as l+-dichlorobenzoyl peroxide, a catalyst such as lead octoate, or aminosilane, and heat-treating at 130 to 150''C for about 5 minutes.

[Problem that the invention seeks to solve]

By the way, the above-mentioned method for producing a silicone adhesive requires preparing an adhesive composition containing a catalyst in advance. Depending on the environment, kelization of the composition may progress or the catalytic activity may decrease, so it is necessary to immediately proceed to the heating step after preparation.

(2) If the catalyst is insufficiently mixed in the adhesive composition, the adhesive performance will be uneven and a pressure-sensitive adhesive sheet with uniform adhesive properties will not be obtained. Things that need to be done well.

(3) Since the thermal crosslinking process is required at high temperatures and over a long period of time, a large heating furnace facility is required. In addition, if either the heating temperature or heating time is insufficient, the cohesive force of the resulting adhesive will be insufficient and cohesive failure will occur in the peel test, so the base material with insufficient heat resistance may be used as a base for adhesive sheets. It cannot be used as a material.

(4) The adhesive strength of the adhesive is determined by the degree of crosslinking, which is influenced by many factors such as the temperature for 2 hours in the thermal crosslinking process and the concentration of the catalyst, so the adhesive performance of the resulting adhesive must be controlled. is difficult.

(5) Even after the thermal crosslinking process is completed, the adhesive properties such as the tackiness and adhesive strength of the adhesive surface may change over a long period of time due to the remaining catalyst.

It has the following drawbacks.

On the other hand, the method for manufacturing a silicone adhesive sheet of the present invention eliminates all the above-mentioned drawbacks of the conventional method for manufacturing a silicone adhesive, and easily produces an adhesive sheet with uniform adhesive performance. , and provides a method for reliably obtaining it.

[Means for solving problems]

The method for producing a silicone pressure-sensitive adhesive sheet of the present invention is to apply a coating agent made of a pressure-sensitive adhesive composition containing an organopolysiloxane to at least one side of a sheet-like base material, and then irradiate the organopolysiloxane with an electron beam. This introduces a crosslinked structure.

That is, in the first invention, a coating agent made of an adhesive composition containing organopolysiloxane is applied to at least one side of a sheet-like base material, and after drying,
A silicone pressure-sensitive adhesive sheet is obtained by irradiating the organopolysiloxane with a 20 M rad electron beam to introduce a crosslinked structure into the organopolysiloxane.

The second invention also provides an adhesive containing 100 parts by weight of an organopolysiloxane and 01 to 20 parts by weight of an organopolysiloxane having an electron beam polymerizable unsaturated bond in the molecule, on at least one side of a sheet-like base material. A coating agent consisting of a sexual composition is applied.

After drying, a silicone pressure-sensitive adhesive sheet is obtained by irradiating the organopolysiloxane with an electron beam of 01 to 10 Mrad to introduce a crosslinked structure into the organopolysiloxane.

In the method for producing a silicone pressure-sensitive adhesive sheet of the present invention, the coating agent applied to at least one side of the sheet-like base material is a pressure-sensitive adhesive composition containing organopolysiloxane, but the crosslinked structure is formed by irradiation with an electron beam. Because of its good adhesive performance after being introduced,
Adhesive compositions containing organopolysiloxanes such as mixtures of silicone resin and silicone gum are preferred.

Silicone resin is, for example, “Polymer Processing” Special Issue 8.
rpp, 93-101 (1971), it is an organopolysiloxane obtained by carrying out a hydrolysis reaction and a combined dehydration condensation reaction of organochlorosilane, and a crosslinked structure can be introduced therein. In addition,
The silicone resin is, for example, an unsubstituted-valent hydrocarbon group such as a methyl group, an ethyl group, a propyl group, a butyl group, a vinyl group, a phenyl group, or a substituted-valent hydrocarbon group in which these are substituted with a halogen atom, etc. It may have one or more substituents. In addition, silicone gum has a linear diorganopolysiloxane structure, and like the silicone resin described above, silicone gum has an unsubstituted structure such as a methyl group, ethyl group, propyl group, butyl group, vinyl group, or phenyl group. It may contain one or more substituents such as a -valent hydrocarbon group or a substituted -valent hydrocarbon group in which a halogen atom or the like is substituted. Rather, when using silicone resins or silicone gums that have substituents such as methyl groups or vinyl groups,
There is an advantage that a crosslinked structure can be easily introduced by electron beam irradiation.

In the method for manufacturing a silicone adhesive sheet of the present invention,
Examples of the sheet-like substrate to which the coating agent made of the adhesive composition containing the organopolysiloxane is applied include films of heat-resistant synthetic resins such as polyimide, fluororesin, and heat-resistant nylon, aluminum foil, and glass fibers. Silicone gum on cloth, even glass fiber cloth,
Impregnated cloth impregnated with silicone or fluororesin or the like is suitable, but films, sheets, etc. with low heat resistance may also be used. In particular, as a sheet-like base material,
When a polymer film having α-hydrogen in the molecule and no quaternary carbon is used, for example, a polymer film made of polyethylene, polypropylene, polystyrene, polyvinyl chloride, etc., in the method of the present invention. Since a crosslinked structure is also introduced into the base material by the electron beam irradiation treatment, a silicone pressure-sensitive adhesive sheet can be obtained using a base material that exhibits excellent chemical resistance, heat resistance, and the like. Also, for example, polymethacrylate.

When a sheet-like substrate is made of a polymer film containing quaternary carbon in its molecules, such as polyvinylidene chloride, cellulose and its derivatives, polytetrafluoroethylene, polytrifluorochloroethylene, etc., it is irradiated. Depending on the irradiation dose of the electron beam, decomposition and deterioration of the base material may occur. However, in the second invention, O1 to 10 M which can suppress deterioration of the base material
The crosslinked structure targeted by the present invention can be introduced into organopolysiloxane by irradiation with a low dose of electron beam called rad.

The electron beam polymerizable unsaturated bond used in the coating agent consisting of the adhesive composition used in this second invention is
Examples of monomers having one or more monomers in the molecule include, for example, 1
．． 6-hexanethiol cyacrylate.

Trimethylo, propane triacrylate, ethylene glycol diacrylate, propylene glycol diacrylate, neopentyl glycol diacrylate, diethylene glycol cyacrylate, triethylene glycol diacrylate, dipropylene glycol diacrylate, 1,5-bentanediol cyacrylate,
Pentaerythritol triacrylate.

Dipentaerythritol hexaacrylate.

Trimethylolpropane triacrylate, methyl acrylate, ethyl acrylate, n-butyl acrylenide, isobutyl acrylate.

? -ethylhexyl acrylate, isodecyl acrylate, lauryl acrylate, stearyl acrylate, 2-hydroxyethyl acrylate, methoxyethyl acrylate), n-cytoxyethyl acrylate, dimethylaminoethyl acrylate, diethylaminoethyl acrylate, n-butylcarbamoyloxy There are acrylates such as ethyl acrylate, their corresponding methacrylates, and polymerizable monomers having an allyl group such as sialyldenpentaerythritol, triallylisocyanine L/-), sialyl phthalate, and trimethylolpropane sialyl ether. However, if the monomer contained in the adhesive composition is less than 01 parts by weight per 100 parts by weight of the organopolysiloxane, the effect of mixing the monomer cannot be obtained, and if it exceeds 20 parts by weight. If a large amount is used, the degree of crosslinking introduced will become too high and the tackiness and adhesive strength of the pressure-sensitive adhesive layer will be significantly reduced. A monomer having one or more bonds in the molecule is added within the range of 0.1 to 20 parts by weight.

It is necessary that it be mixed. In addition, in the method for manufacturing a silicone adhesive sheet of the second invention,
The adhesive composition containing organopolysiloxane contains a monomer having one or more of the above-mentioned electron beam polymerizable unsaturated bonds in one molecule, but the proportion of the monomer added increases. The more the pressure-sensitive adhesive layer of the resulting pressure-sensitive adhesive sheet becomes weaker, the more the adhesive force and tackiness of the resulting pressure-sensitive adhesive sheet decreases, and the cohesive force and heat resistance decrease.

Since it has the property of improving chemical resistance, etc., the adhesive performance of the adhesive layer surface of the adhesive sheet can be controlled by the amount of the monomer mixed in.

A coating agent made of an adhesive composition containing an organopolysiloxane can be used to adjust the molecular weight of the polysiloxane,
Usually 10% by heating, dilution with an organic solvent, etc.
After adjusting the viscosity to 0,000 centistokes or less, the sheet-like base material is coated, for example, by roll coating or gravure coating.

It is applied with air knife coating, hot melt coating, force-tray coating, etc., but 3! If it is less than '(dry)/m'', the adhesive strength of the adhesive layer surface of the resulting adhesive sheet will not be sufficient;
Even if it exceeds ary/-, there is no improvement in the adhesive performance of the adhesive layer surface, which is not only uneconomical, but also causes extrusion of the adhesive sheet during lamination and cohesive failure during peeling. The adhesive composition is preferably applied within the range of 3 to 50 f7 (dry)/m''.

After applying the adhesive composition containing organopolysiloxane to a sheet-like base material, it is emitted from an electron beam accelerator such as a Kotscroft-Walton type, bumpgraph type, resonance transformation type, linear type, dynamidron type, or high frequency type. This method introduces a crosslinked structure into the organopolysiloxane in the adhesive composition described in Section 11ff by irradiating it with an electron beam. This is achieved by abstracting a hydrogen atom from an alkyl group, especially a methyl group, and if the organopolysiloxane molecule has an unsaturated bond such as a vinyl group, the addition reaction by this functional group will proceed and cause crosslinking. Introduction of structure is achieved. The irradiated electron beam is generally
130-300Kev1 preferably 150-200K
A material having an energy of about eV is used, and the degree of crosslinking introduced into the organopolysiloxane is mainly determined by the amount of electron beam irradiation at this time. If the amount of electron beam irradiation is too small, the introduction of crosslinked structure will not be sufficient and the heat resistance and chemical resistance of the adhesive layer will be insufficient.If the amount of irradiation is too high, the adhesion of the adhesive layer Since the strength and tackiness will decrease, when using an adhesive composition that does not contain a monomer having an electron beam polymerizable unsaturated bond, it is recommended that the irradiation amount be within the range of 0.05 to 20 Mraa. , In addition, when using an adhesive composition containing a monomer having an electron beam polymerizable unsaturated bond, 01-
A dose within the LOMrad range is utilized.

(Example) Hereinafter, the specific structure of the method for manufacturing a silicone pressure-sensitive adhesive sheet of the present invention will be explained with reference to Examples.

Example 1 An adhesive composition containing organopolysiloxane [manufactured by Shin-Etsu Chemical Co., Ltd.: KR101-10°] was applied to one surface of a sheet-like base material made of a polyimide film with a thickness of 50 μm that had been subjected to corona discharge treatment. 302 (60% solids, toluene/xylene mixed solvent) by roll coating method.
It was applied at a ratio of solid component)/c and dried. Next, using an electron beam irradiation device [Electro Curtain: manufactured by E81], the irradiation weight was 3 Mrad, 5 Mrad, L OM at an accelerating voltage of 165 KV in a nitrogen gas atmosphere.
rad, to obtain three types of silicone adhesive sheets [1] to Ciii) which are the objects of the present invention.

Comparative Example 1 According to the same procedure as in Example 1, an adhesive composition was applied at a ratio of 30 l/m' and dried to obtain an adhesive sheet [1] for comparison.

Comparative Example 2 An organopolysiloxane containing 1.0 wt-% benzyl peroxide based on organopolysiloxane was added to one surface of a sheet-like base material made of a polyimide film with a thickness of 50μ that had been subjected to corona discharge treatment. Adhesive composition containing polysiloxane [solid component 60%, toluene/
xylene mixed solvent] was applied at a rate of 309 (solid components)/m by roll coating, dried at 100°C for 30 seconds, and then heat-treated at 160'Q for 5 minutes and 17fl. A pressure-sensitive adhesive sheet [2] was obtained.

JI of the adhesive sheets obtained in the above Examples and Comparative Examples
Table 1 shows the measurement results 1 of pole tack, adhesive strength, and heat-resistant holding power using S Z 0237.

In addition, the adhesion strength (180 degree peel bond/1n
ch) are shown in Table 2.

Table 2 further shows the electrical properties of adhesive sheet (Cil) and adhesive sheet [2] according to JIS C-2L 22.
The determined results are shown in Table 3. In addition, the measurement is 23
It was carried out under the conditions of 96% RH and 96 hrs.

Table 3 also shows the adhesive strength of the adhesive layer [to stainless steel plate 1go] for adhesive sheet) [:il) and adhesive sheet [2].
Degree of peeling! Table 4 shows the changes over time of 7/1 nch). The samples were left in an atmosphere at 150°C for a predetermined number of days.

Table 4 From Table 1, it is confirmed that in the method for producing a silicone adhesive sheet of the present invention, the adhesive force and tackiness of the resulting adhesive layer are controlled by the electron beam irradiation dose. It can be confirmed that an adhesive layer exhibiting excellent properties in terms of heat resistance holding power can be obtained.

In addition, Tables 2 and 3 show that the method of the present invention yields a silicone adhesive sheet with high physical properties that is comparable in adhesive strength to various substrates, electrical properties, etc. to thermally crosslinked adhesive sheets. is confirmed.

Furthermore, as shown in Table 4, in thermally crosslinkable silicone adhesive sheets, the crosslinking reaction progresses gradually due to the peroxide remaining in the adhesive layer, so the adhesive strength of the adhesive layer decreases. changes over time and is unstable, but in the method of the present invention, the adhesive force of the adhesive layer does not change over time,
It is confirmed that a pressure-sensitive adhesive sheet that exhibits stable adhesive strength can be obtained.

Example 2 Trimethylolpropane triacrylate [manufactured by Kyoeisha Yushi Co., Ltd.:
Adhesive composition containing TMPTA) and organopolysiloxane [Shin-Etsu Chemical Co., Ltd.: KRIOl-10, solid content 60%.

Tree fJ'F added in toluene/xylene mixed solvent]
A coating agent consisting of I-liquid was applied at a ratio of 30 g (solid component)/m' by the roll foot method.

Dry. Next, using an electron beam irradiation device [Electro Curtain: manufactured by ESI], 1
Electron beam irradiation was performed under the conditions of 65 KV and 0.3 M rad to obtain three types of silicone adhesive sheets L: iV) to [v1] which are the objects of the present invention.

Comparative Example Adhesive composition containing organopolysiloxane on one surface of a sheet-like base material made of a Teflon film with a thickness of 50 μm that has been subjected to corona discharge treatment [Shin-Etsu Chemical Co., Ltd.]
: A coating agent consisting of KRlol-10゜solid component 60%, toluene/xylene mixed solvent] was applied to the roll coating method using Ten1ESI Co., Ltd.] under a nitrogen gas atmosphere at l 65 KV and 0.3 Mrad. Electron beam irradiation was performed under these conditions to obtain a silicone adhesive sheet for comparison.

Said example? silicone adhesive sheet obtained in (iv)
Table 5 shows the measurement results of pole tack, adhesive strength, and heat-resistant holding power using RIS Z 0237 for silicone pressure-sensitive adhesive sheets [Z] obtained in ) to [v1] and Comparative Example 5.

From the results shown in Table 5, it is clear that by using a coating agent consisting of the organopolysiloxane-containing adhesive composition S, in which a monomer having an electron beam polymerizable unsaturated bond is added to the molecule, it is possible to reduce the radiation dose. It was confirmed that an adhesive layer with good heat-resistance holding power could be obtained even when irradiated with an electron beam of It is confirmed that the adhesive force can be controlled.

[Operation and effects of the invention]

In the present invention, a silicone adhesive sheet is obtained by applying a coating agent made of a composition containing an organopolysiloxane to at least one side of a sheet-like base material, drying the coating agent, and then irradiating the coating agent with an electron beam.

Therefore, in the present invention, there is no need to prepare a catalyst-containing adhesive composition in advance, unlike in the case of manufacturing a silicone adhesive sheet by a thermal crosslinking method, and a pressure-sensitive adhesive sheet with uniform adhesive properties can be obtained. This action and effect is produced.

Furthermore, as described above, the method of the present invention has the effect that a pressure-sensitive adhesive sheet with stable adhesive properties can be obtained because the coating agent does not contain a catalyst.

Furthermore, in the first invention, by changing the irradiation amount of the irradiated electron beam, and in the second invention, by changing the irradiation amount of the irradiated electron beam and the electron beam polymerizable unsaturation in the coating agent. By changing the amount of the bond-containing monomer added, the properties of the adhesive layer can be controlled, making it easy to control manufacturing quality.

In addition, in the method of the present invention, the crosslinking structure is introduced into the organopolysiloxane by electron beam irradiation, so there are drawbacks such as the slow crosslinking rate that occurs when using ultraviolet rays, and the disadvantages of using alpha rays. There is no need to add a sensitizer (27), which is required when using a sensitizer, and the operation is simple and the irradiation dose can be easily controlled.

be effective.

Claims (2)

[Claims] (1) A silicone-based material characterized by applying a coating agent made of an adhesive composition containing an organopolysiloxane to at least one side of a sheet-like base material, and then irradiating it with an electron beam of 0.5 to 20 Mrad. Method for manufacturing adhesive sheets. (2) An adhesive composition containing 100 parts by weight of an organopolysiloxane and 0.1 to 20 parts by weight of a monomer having an electron beam polymerizable unsaturated bond in the molecule on at least one side of a sheet-like base material. A coating agent is applied, and then
A method for producing a silicone pressure-sensitive adhesive sheet, which comprises irradiating with an electron beam of 0.1 to 10 Mrad.