JP6967185B2 - Hot melt type polysiloxane adhesive - Google Patents

Description

The present invention relates to a hot melt type polysiloxane adhesive.

While general adhesives cure and exhibit adhesiveness due to volatilization of solvents and chemical reactions, hot-melt adhesives can be bonded in a cycle of heat melting and cooling solidification, and bonding can be completed in a short time. .. The hot melt adhesive is generally composed mainly of olefin-based polyester-based, ethylene-vinyl acetate copolymer (EVA), synthetic rubber, polyamide-based, urethane-based polymer and the like.
In general, linear siloxane polymers have good wettability to substrates with low surface free energy and excellent heat resistance, but are oily or waxy and have very weak adhesive strength, so they can be used as adhesives. When used, adhesion has been achieved by modifying the ends of the siloxane polymer and actively cross-linking, for example, by hydrosilylation reaction with vinyl group and silane, urethanization reaction with isocyanate and alcoholic hydroxyl group, moisture curing and the like.

As examples of the silicone-based adhesive, Patent Document 1 describes (A) 100 parts by weight of a heat-curable organopolysiloxane composition, (B) 1 to 100 parts by weight of a reinforcing silica fine powder, and (C) adhesiveness. A silicone rubber adhesive composition for a mobile body is disclosed, which comprises 0.1 to 50 parts by weight of an imparting component.
Further, Patent Document 2 shows good gap filling property even in thermal pressure bonding at low pressure with respect to an adherend having large surface irregularities, and is reactive to be cured and firmly adhere to the adherend. An object of the present invention is to provide a hot melt type silicone-based adhesive, (A) an organopolysiloxane resin having a softening point of 40 to 250 ° C., and (B) an organopolysiloxane containing a liquid or raw rubber-like alkenyl group at 25 ° C. C) (i) Silicon atom-bonded hydrogen atom-containing organopolysiloxane and (ii) Silicon atom-bonded alkoxy group-containing organosilicon compound, or (iii) Silicon atom-bonded hydrogen atom and silicon atom-bonded alkoxy group-containing organopolysiloxane, A hot melt type silicone-based adhesive comprising (D) a catalyst for a hydrosilylation reaction and (E) a hydrosilylation reaction inhibitor has been proposed.
As described above, the silicone-based adhesive generally contains silica, calcium carbonate, or the like as a reinforcing agent in addition to the reactive polysiloxane, and further contains a cross-linking agent and a curing catalyst to be cured.
On the other hand, the present inventors have developed an all-siloxane polymer having a structure in which a cage-type bifunctional silsesquioxane derived from a double-decker type silsesquioxane and a linear siloxane are alternately bonded, and optically. It has been found that it has unique characteristics such as characteristics and electrical characteristics, and its manufacturing method has been improved (for example, Patent Documents 3 to 5).

Japanese Unexamined Patent Publication No. 2004-331820 Japanese Unexamined Patent Publication No. 2006-274007 International Publication No. 2008/07766 Japanese Unexamined Patent Publication No. 2010-116464 Japanese Unexamined Patent Publication No. 2017-014320

An object of the present invention is to provide a hot melt type polysiloxane adhesive that achieves an adhesive strength equal to or higher than that of a non-silicone adhesive or a non-hot melt silicone adhesive.

Although the present inventors have a structure in which a cage-type bifunctional silsesquioxane derived from a double-decker type silsesquioxane and a linear siloxane are alternately bonded, the total siloxane polymer has a silanol group at the end. It was found that the adherend (base material) can be firmly adhered only by softening / melting and then cooling without any particular reaction. It was also found that this siloxane polymer can firmly adhere various adherends (base materials) without adding a reinforcing agent, a cross-linking agent, or a curing catalyst. Furthermore, the present inventors have found that the siloxane polymer can be easily peeled off from the substrate by heating it to a temperature equal to or higher than the glass transition temperature after bonding with the siloxane polymer.
That is, the present inventors can bond various substrates to a double-decker type silsesquioxane compound polymer having a specific structure without a cross-linking reaction, and a non-silicone hot melt adhesive. We have found that it has the same level of adhesive strength as (unreacted type), or higher adhesive strength, is excellent in transparency, and is useful as a reversibly removable hot melt adhesive, and completed the present invention. rice field.

（式（Ａ）中、ｍは独立して１〜３１の整数を表し；ｎは１〜１，０００の整数を表し；Ｒ⁰は独立して炭素数６〜２０のアリール又は炭素数５又は６のシクロアルキルを表し；Ｒ¹及びＲ²は独立して、水素、炭素数２〜４０のアルケニル、炭素数１〜４０のアルキル、任意の水素が独立してハロゲン若しくは炭素数１〜２０のアルキルで置き換えられてもよい炭素数６〜２０のアリール、又はアリールにおける任意の水素が独立してハロゲン若しくは炭素数１〜２０のアルキルで置き換えられてもよい炭素数７〜２０のアリールアルキルを表し；
前記炭素数１〜４０のアルキルにおいて、任意の水素は独立してフッ素で置き換えられてもよく、任意の−ＣＨ₂−は独立して−Ｏ−又は炭素数５〜２０のシクロアルキレンで置き換えられてもよく；
前記アリール又はアリールアルキルの置換基である炭素数１〜２０のアルキルにおいて、任意の水素は独立してフッ素で置き換えられてもよく、任意の−ＣＨ₂−は独立して−Ｏ−、炭素数５〜２０のシクロアルキレン又はフェニレンで置き換えられてもよく；
前記アリールアルキルのアルキレンにおいて、その炭素数は１〜１０であり、任意の水素は独立してフッ素で置き換えられてもよく、そして任意の−ＣＨ₂−は独立して−Ｏ−、−ＣＨ＝ＣＨ−又は炭素数５〜２０のシクロアルキレンで置き換えられてもよい。）
［２］ 式（Ａ）中、Ｒ⁰がフェニルを含む、［１］又は［２］に記載のホットメルト型ポリシロキサン接着剤。
［３］ 式（Ａ）中、Ｒ^１及びＲ^２がメチルまたはフェニルを含む、［１］又は［２］に記載のホットメルト型ポリシロキサン接着剤。
［４］ 式（Ａ）中、ｍが平均で１以上１０以下である、［１］〜［３］の何れかに記載のホットメルト型ポリシロキサン接着剤。
［５］ 前記ケイ素化合物のガラス転移温度が３０℃以上１８０℃以下である、［１］〜［４］の何れかに記載のホットメルト型ポリシロキサン接着剤。
［６］ 前記ケイ素化合物のガラス転移温度以上の温度で被着材から可逆的に着脱できる、［１］〜［５］の何れかに記載のホットメルト型ポリシロキサン接着剤。
［７］ ガラス、シリコンウェハ、金属、金属酸化物、プラスチックフィルム又は疎水化基材に接着可能である、［１］〜［６］の何れかに記載のホットメルト型ポリシロキサン接着剤。
［８］ 硬化剤を実質的に含まない、［１］〜［７］の何れかに記載のホットメルト型ポリシロキサン接着剤。
［９］ さらに無機フィラーを含む、［１］〜［８］の何れかに記載のホットメルト型ポリシロキサン接着剤。
［１０］ 前記ケイ素化合物以外の成分を実質的に含まない、［１］〜［８］の何れかに記載のホットメルト型ポリシロキサン接着剤。 That is, the embodiment of the present invention includes the following configurations.
[1] A hot-melt type polysiloxane adhesive represented by the following formula (A) and containing a silicon compound having a glass transition temperature of 30 ° C. or higher and 200 ° C. or lower.

(In the formula (A), m independently represents an integer of 1-31; n represents an integer of 1 to 1,000; R ⁰ independently represents an aryl having 6 to 20 carbon atoms or 5 or 5 carbon atoms. Represents a cycloalkyl of 6; R ¹ and R ² independently represent hydrogen, an alkenyl having 2 to 40 carbon atoms, an alkyl having 1 to 40 carbon atoms, any hydrogen independently having a halogen or 1 to 20 carbon atoms. Represents an aryl having 6 to 20 carbon atoms which may be replaced by an alkyl, or an arylalkyl having 7 to 20 carbon atoms in which any hydrogen in the aryl may be independently replaced by a halogen or an alkyl having 1 to 20 carbon atoms. ;
In the alkyl having 1 to 40 carbon atoms, any hydrogen may be independently replaced by fluorine, and any −CH ₂ − is independently replaced by −O− or a cycloalkylene having 5 to 20 carbon atoms. May;
In the alkyl having 1 to 20 carbon atoms which is a substituent of aryl or arylalkyl, any hydrogen may be independently replaced with fluorine, and any −CH ₂ − is independently −O−, carbon number. May be replaced with 5-20 cycloalkylenes or phenylene;
In the arylalkyl alkylene, the carbon number is 1-10, any hydrogen may be independently replaced by fluorine, and any −CH ₂₋ is independently −O−, −CH =. It may be replaced with CH- or cycloalkylene having 5 to 20 carbon atoms. )
[2] The hot-melt type polysiloxane adhesive according to [1] or [2] ^{, wherein R 0} contains phenyl in the formula (A).
[3] The hot melt type polysiloxane adhesive according to [1] or [2] ^{, wherein R 1} and R ² contain methyl or phenyl in the formula (A).
[4] The hot-melt type polysiloxane adhesive according to any one of [1] to [3], wherein m is 1 or more and 10 or less on average in the formula (A).
[5] The hot-melt type polysiloxane adhesive according to any one of [1] to [4], wherein the glass transition temperature of the silicon compound is 30 ° C. or higher and 180 ° C. or lower.
[6] The hot melt type polysiloxane adhesive according to any one of [1] to [5], which can be reversibly attached to and detached from an adherend at a temperature equal to or higher than the glass transition temperature of the silicon compound.
[7] The hot melt type polysiloxane adhesive according to any one of [1] to [6], which can be adhered to a glass, a silicon wafer, a metal, a metal oxide, a plastic film or a hydrophobic substrate.
[8] The hot melt type polysiloxane adhesive according to any one of [1] to [7], which does not substantially contain a curing agent.
[9] The hot melt type polysiloxane adhesive according to any one of [1] to [8], which further contains an inorganic filler.
[10] The hot-melt type polysiloxane adhesive according to any one of [1] to [8], which does not substantially contain components other than the silicon compound.

INDUSTRIAL APPLICABILITY The present invention provides a hot-melt type polysiloxane adhesive that achieves an adhesive strength equal to or higher than that of a non-silicone adhesive or a non-hot melt silicone adhesive.

Hereinafter, embodiments of the present invention will be described in detail, but the following description is an example (representative example) of embodiments of the present invention, and the present invention is not limited to these contents. Moreover, the embodiments of the present invention can be combined as appropriate.

<Hot melt type polysiloxane adhesive>
The hot-melt type polysiloxane adhesive according to an embodiment of the present invention contains a silicon compound represented by the following formula (A) and having a glass transition temperature of 30 ° C. or higher and 200 ° C. or lower.

In formula (A), m independently represents an integer of 1-31; n represents an integer of 1 to 1,000; R ⁰ independently represents an aryl having 6 to 20 carbon atoms or 5 or 6 carbon atoms. R ¹ and R ² independently represent hydrogen, an alkenyl having 2 to 40 carbon atoms, an alkyl having 1 to 40 carbon atoms, and any hydrogen independently having a halogen or an alkyl having 1 to 20 carbon atoms. Represents an aryl having 6 to 20 carbon atoms which may be replaced by, or an arylalkyl having 7 to 20 carbon atoms in which any hydrogen in the aryl may be independently replaced by a halogen or an alkyl having 1 to 20 carbon atoms;
In the alkyl having 1 to 40 carbon atoms, any hydrogen may be independently replaced by fluorine, and any −CH ₂ − is independently replaced by −O− or a cycloalkylene having 5 to 20 carbon atoms. May;
In the alkyl having 1 to 20 carbon atoms which is a substituent of aryl or arylalkyl, any hydrogen may be independently replaced with fluorine, and any −CH ₂ − is independently −O−, carbon number. May be replaced with 5-20 cycloalkylenes or phenylene;
In the arylalkyl alkylene, the carbon number is 1-10, any hydrogen may be independently replaced by fluorine, and any −CH ₂₋ is independently −O−, −CH =. It may be replaced with CH- or cycloalkylene having 5 to 20 carbon atoms.

R ⁰ independently represents an aryl having 6 to 20 carbon atoms or a cycloalkyl having 5 or 6 carbon atoms. Any two or more of R ^0s may be the same or different. R ⁰ preferably contains phenyl, and more preferably all phenyl, from the viewpoint of obtaining high adhesive strength and easiness of synthesis.
In formula (A), R ¹ may be all the same or different. As R ¹ , for example, from the viewpoint of easiness of synthesis, an alkyl having 1 to 40 carbon atoms or any hydrogen may be independently replaced with a halogen or an alkyl having 1 to 20 carbon atoms. It is preferably aryl, more preferably an alkyl having 1 to 20 carbon atoms or an aryl having 6 to 20 carbon atoms, preferably containing methyl or phenyl, and being all methyl or all phenyl. Is even more preferable. In formula (A), R ² is defined in the same way as ^{R 1.} R ² may be all the same or different. As R ² , for example, from the viewpoint of easiness of synthesis, an alkyl having 1 to 40 carbon atoms or any hydrogen may be independently replaced with a halogen or an alkyl having 1 to 20 carbon atoms. It is preferably aryl, more preferably an alkyl having 1 to 20 carbon atoms or an aryl having 6 to 20 carbon atoms, preferably containing methyl or phenyl, and being all methyl or all phenyl. Is even more preferable.

In formula (A), m independently represents an integer of 1-31; n represents an integer of 1 to 1,000. m is preferably 1 to 10 and more preferably 2 to 8 from the viewpoint of ease of synthesis and the influence of the ratio of the silsesquioxane moiety to the siloxane moiety on the physical characteristics of the compound of the formula (A). be. Further, when the molecular weight and m are determined, n is interlocked and determined by the following mathematical formula (1).
Molecular weight = {A + (B × m + C)} × n + terminal H ₂ O formula (1)
A: Silcesquioxane unit B: Siloxane unit C: -O-Si (R ² ) _2-

Conventional silicone (siloxane) hot melt adhesives are reactive, that is, softened or melted by heating, hydrosilylation reaction with vinyl group and silane, urethanization reaction with isocyanate and alcoholic hydroxyl group, and moisture curing (in air at room temperature). It is hardened by a chemical reaction with the water content of the above (hardened), and the base material is adhered. As described above, since the conventional silicone (siloxane) -based hot melt adhesive is subjected to a cross-linking reaction, it is difficult to easily and reversibly attach and detach it once it is adhered.
On the other hand, the hot-melt type polysiloxane adhesive according to one embodiment of the present invention is solid at room temperature (25 ° C to 27 ° C), is heated to a temperature equal to or higher than the glass transition temperature to melt, and then cooled to solidify. Acts as an adhesive. The hot-melt type polysiloxane adhesive made of a silicon compound represented by the formula (A) can firmly bond various substrates without adding a reinforcing agent, a cross-linking agent, or a curing catalyst. Further, the adhesive layer made of the hot-melt type polysiloxane adhesive according to the embodiment of the present invention can be easily peeled off from the adherend by heating it to a temperature equal to or higher than the glass transition temperature of the adhesive.
The hot-melt type polysiloxane adhesive according to the embodiment of the present invention can be a hot-melt polysiloxane adhesive that does not substantially contain a curing agent. Further, the hot-melt type polysiloxane adhesive according to the embodiment of the present invention may be a hot-melt type polysiloxane adhesive that does not substantially contain components other than the silicon compound. That is, since the compound represented by the formula (A) can be used alone as an adhesive, a curing agent or the like is not required, and a mixing step with other components is not required, so that low-cost and simple manufacturing is not required. It is possible to provide an adhesive having high adhesiveness to various substrates (adhesive materials) in the process. Here, the term "substantially free" as used herein means, if present, an amount or less that affects the hot-melt polysiloxane adhesive of the present invention, if present, if not less than that. Refers to the quantity. Specifically, in the case of a curing agent, the content of the curing agent is, for example, 1% by mass or less, preferably 0.5% by mass or less, more preferably 0.1% by mass or less, and ideally, the curing agent is blended. It means that it has not been done. When the component other than the silicon compound is substantially not contained, the content of the component other than the silicon compound is, for example, 1% by mass or less, preferably 0.5% by mass or less, and more preferably 0.1% by mass or less. Ideally, it means that no component other than the silicon compound is blended.

The glass transition temperature of the silicon compound represented by the formula (A) has a lower limit of 30 ° C. and an upper limit of 200 ° C. from the viewpoint of handling and usage environment. The dehydration condensation of SiOH is expected to start from around 250 ° C., and at 200 ° C. or lower, the cross-linking reaction due to the dehydration condensation of SiOH does not occur, and the silicon compound represented by the formula (A) can be reversibly attached and detached. It is believed that a hot melt adhesive can be achieved.
The glass transition temperature of the silicon compound represented by the formula (A) can be controlled by changing m and n. That is, by changing "m" and "n" in the formula (A), the operating temperature region of the hot melt type polysiloxane adhesive (hereinafter, may be referred to as "operating temperature region") is controlled. Can be done. Therefore, "m" and "n" may be selected depending on the operating temperature range. In particular, the glass transition temperature can be significantly changed by changing the siloxane chain length "m" of the silicon compound represented by the formula (A). When the operating temperature range is 30 ° C to 200 ° C, the weight average molecular weight (Mw) is preferably 10,000 to 300,000, more preferably 30,000 to 250,000, still more preferably 40,000. ~ 150,000.
Here, m in the equation (A) may give a plurality of integers instead of a single one. In this case, it may be a mixture of polymers in which m is an integer of 1 to 20. That is, when the silicon compound represented by the formula (A) is a mixture of polymers giving a plurality of m, m may be expressed as a decimal number instead of an integer. Similarly, n may be represented by a decimal number instead of an integer.
As used herein, the glass transition temperature (Tg) is measured by thermomechanical analysis (TMA). Specifically, it can be obtained by the following method.
<Tg measurement method>
Thermomechanical analyzer: "TMA / SS7100" manufactured by SII Nanotechnology Co., Ltd. (currently Hitachi High-Tech Science Corporation)
Using a needle-inserted probe, the temperature is raised at a heating rate of 1 ° C./min from a state where a constant load (90 mN) is applied to the sample (polymer), and the point where the position of the probe changes significantly is defined as Tg.

The silicon compound represented by the formula (A) can be produced, for example, by the methods described in JP-A-2010-116464A and JP-A-2017-014320.
From the viewpoint of productivity, it is preferable to produce by the method described in JP-A-2017-014320.
The weight average molecular weight of the silicon compound represented by the formula (A) can be determined by gel permeation chromatography (GPC), and more specifically, can be determined under the following conditions.
<GPC measurement conditions>
Column: Showa Denko Co., Ltd. Shodex KF-806M
Mobile phase: THF (Nacalai Tesque Co., Ltd.)
Flow rate: 1 ml / min
Temperature: 45 ° C
Detector: UV
Molecular weight standard sample: Polystyrene with known molecular weight

The hot-melt type polysiloxane adhesive according to another embodiment of the present invention is a hot-melt type polysiloxane adhesive containing a component other than the compound represented by the formula (A) in addition to the silicon compound represented by the formula (A). It can be a polysiloxane adhesive. The hot-melt type polysiloxane adhesive according to the present embodiment contains a silicon compound represented by the formula (A) and having a glass transition temperature of 30 ° C. or higher and 200 ° C. or lower in an amount of 50% by mass or more and 99% or more based on the total mass of the adhesive. It is preferably contained in an amount of less than, more preferably 50% by mass or more and 98% by mass or less, and further preferably 50% by mass or more and 97% by mass or less. The glass transition temperature of the hot melt type polysiloxane adhesive of the present embodiment can be adjusted by the glass transition temperature of the compound represented by the formula (A) and the components other than the compound represented by the formula (A). ..
The components other than the silicon compound represented by the formula (A) that can be contained in the hot melt type polysiloxane adhesive according to the present embodiment are wet from the viewpoint of adjusting various physical properties of the adhesive and from the viewpoint of adhesion. Examples thereof include sex improvers, surfactants, plasticizers, ultraviolet absorbers, antioxidants, antistatic agents, silane coupling agents, inorganic fillers typified by silica and alumina, and organic fillers.

<Inorganic filler>
The hot-melt type polysiloxane adhesive according to the embodiment of the present invention may contain an inorganic filler from the viewpoint of improving wear resistance. Examples of the inorganic filler include silica and alumina.
The average particle size of the inorganic filler is not limited as long as it is on the nano-order, but is preferably 1 to 100 nm, more preferably 1 to 40 nm, and further preferably 1 to 20 nm from the viewpoint of transparency. Further, it is preferable that the particle size distribution is narrow.
The shape of the inorganic filler is not particularly limited, but may be spherical, amorphous, flaky or the like. A spherical shape is preferable from the viewpoint of improving adhesion and transparency. When the shape of the inorganic filler is other than spherical, the average particle size of the inorganic filler means the average maximum diameter of the inorganic filler.
Further, the inorganic filler may be surface-treated with a silane coupling agent or the like, and surface-modified colloidal silica is preferable.
In the hot melt type polysiloxane adhesive according to the embodiment of the present invention, the content of the inorganic filler is mass% with respect to the total amount of the adhesive, preferably 0.01% by mass to 50% by mass, and more preferably. 1% by mass to 50% by mass.
In the present embodiment, the inorganic filler itself may be added to the silicon compound represented by the formula (A) for the preparation of the adhesive, or a commercially available product in which the inorganic filler is dispersed in the resin may be used. Alternatively, a commercially available product in which the inorganic filler is dispersed in the solvent may be used.
Examples of such commercially available products include EVONICINDUSTRIES nanosilica-dispersed epoxy resin [Nanopop® series (C620, F400, E500, E600, E430)] in which 40% by mass of nanosilica is dispersed in the epoxy resin, and acrylate. Nanocryl® series (C130, C140, C145, C146, C150, C153, C155, C165, C350) in which 50% by mass of nanosilica is dispersed in a resin, a series of organosilica sol manufactured by Nissan Chemical Co., Ltd., methyl ethyl ketone ( MEK), a silica sol dispersed in an aqueous solvent such as methyl isobutyl ketone (MIBK), cyclohexanone (CHO), ethyl acetate (EAC), propylene glycol monomethyl ether acetate (PMA-ST), toluene (TOR-ST), MEK. -ST-40, MEK-ST-L, MEK-ST-ZL, MEK-ST-UP, MIBK-ST, MIBK-ST-L, CHO-ST-M, EAC-ST, PMA-ST, TOR-ST And so on.

The hot-melt type polysiloxane adhesive according to the embodiment of the present invention is solid at room temperature (25 ° C to 27 ° C), and is molded into a size and shape according to the purpose of use, such as beads and small pieces. Can be used.
The glass transition temperature of the hot melt type polysiloxane adhesive according to the embodiment of the present invention is 30 ° C. or higher and 200 ° C. or lower, preferably 30 ° C. or higher and 180 ° C. or lower, and 35 ° C. or higher from the viewpoint of handling and usage environment. 80 ° C. or lower is more preferable.
The open time of the hot-melt type polysiloxane adhesive according to the embodiment of the present invention (the time available for bonding from the application of the adhesive to the adherend to the bonding) is set as long as the adhesion of dust can be avoided. Not particularly limited.
The set time (time required for solidification) of the hot-melt type polysiloxane adhesive according to the embodiment of the present invention is usually several seconds to several minutes, preferably 1 second to 10 minutes, and more preferably. It takes 10 seconds to 5 minutes.

<How to use>
The method of using the hot melt type polysiloxane adhesive according to the embodiment of the present invention will be described below.
One aspect of the method of using the hot melt type polysiloxane adhesive is a method of adhering the first base material to the second base material.
(I) The step of heating and melting the hot melt type polysiloxane adhesive, and
(Ii) A step of bringing the first base material into contact with the molten hot melt type polysiloxane adhesive, and
(Iii) A step of bringing the second base material into contact with the molten hot melt type polysiloxane adhesive, and
(Iv) includes a step of cooling the molten hot melt type polysiloxane adhesive.

(I) Step of heating and melting the hot-melt type polysiloxane adhesive The step of heating and melting the hot-melt type polysiloxane adhesive is the glass transition temperature of the hot-melt type polysiloxane adhesive and the adherend. A known method may be used depending on the substrate. For example, the hot melt type polysiloxane adhesive may be melted by heating at a temperature of + 5 ° C to + 20 ° C, which is the glass transition temperature.
(Ii) Step of bringing the first base material into contact with the molten hot-melt type polysiloxane adhesive The method of bringing the first base material into contact with the melted hot-melt type polysiloxane adhesive is not particularly limited and is melted. A hot-melt type polysiloxane adhesive may be applied onto the first base material, or a solid hot-melt type polysiloxane adhesive may be placed on the first base material and melted by heating and melting. The hot melt type polysiloxane adhesive may be brought into contact with the first substrate.
(Iii) Step of contacting the second base material with the molten hot melt type polysiloxane adhesive In the step of contacting the second base material with the molten hot melt type polysiloxane adhesive, the second base material is brought into contact with the above. It is not particularly limited as long as it comes into contact with the molten hot melt type polysiloxane adhesive. In this step (iii), pressure may be applied. For example, when used for laminating glass, pressure may be applied under the condition of pressure of 0.01 MPa to 0.1 MPa.
(Iv) Following the step (iii) of cooling the molten hot-melt type polysiloxane adhesive, the melted hot-melt type polysiloxane adhesive is cooled ((iv) step). Examples of the cooling method include cooling in an atmospheric atmosphere.
As a method of using the hot melt type polysiloxane adhesive of the present invention, (i) to (iii) may be performed at the same time. For example, a glass substrate is used as an adherend, a hot melt type polysiloxane adhesive is placed on the glass substrate, and a glass substrate is placed on the glass substrate as another adherend, and the temperature is 70 ° C. for 20 minutes at 100 ° C. Examples thereof include a method of heating in an oven at 200 ° C. for 20 minutes, then taking it out of the oven and allowing it to cool.

As the adherend, glass such as white plate glass, blue plate glass, silica-coated blue plate glass and hydrophobic glass; silicon wafer and hydrophobic silicon wafer; metal such as aluminum plate, copper plate, nickel plate, stainless plate; polycarbonate, polyester, Synthetic resin sheets and films such as acrylic resin, vinyl chloride resin, polyamide resin, polyamideimide, polyimide, triacetate, and diacetate; cycloolefin resin including norbornene resin (trade name: Zeonoa, Zeonex, Nippon Zeon Co., Ltd.) , Trade name; Arton, JSR Co., Ltd., methacrylic styrene, polysulfone, alicyclic acrylic resin, transparent resin substrate used for optical applications such as polyarylate; ceramic plate; urethane rubber, styrene rubber and the like.
These adherends may be pretreated, and examples of pretreatment include chemical treatment with a silane coupling agent, sandblast treatment, corona discharge treatment, ultraviolet treatment, plasma treatment, ion plating, sputtering, etc. Gas phase reaction method, vacuum deposition, etc. are included.

<Adhesive layer made of hot melt type polysiloxane adhesive>
The thickness of the adhesive layer made of the hot-melt type polysiloxane adhesive according to the embodiment of the present invention can be adjusted according to the intended use, but is preferably 0.01 mm to 1 mm, preferably 0.03 mm to 0.5 mm. More preferably, 0.05 to 0.3 mm is even more preferable.

The adhesive strength (tensile shear stress) of the adhesive layer made of the hot-melt type polysiloxane adhesive according to the embodiment of the present invention is about the same as that of the conventional reactive silicone (siloxane) -based hot-melt type polysiloxane adhesive, or Shows higher adhesive strength. In particular, when used at a thickness of 0.07 mm to 0.24 mm, a high adhesive force can be achieved with a tensile shear stress of about 8 to 20 MPa.
Further, the hot-melt type polysiloxane adhesive according to the embodiment of the present invention can be adhered to the above-mentioned various substrates and has a strong adhesive force, so that it is suitably used for various uses.
Further, the adhesive layer made of the hot-melt type polysiloxane adhesive according to the embodiment of the present invention can be easily peeled off from the adherend (adhesive material) by heating above the glass transition temperature of the adhesive. can.
Further, since the hot melt type polysiloxane adhesive according to the embodiment of the present invention uses a silicon compound which is a siloxane polymer, it is also excellent in transparency. Therefore, it is also suitably used for applications that require transparency. For example, it is suitably used for laminating glass, temporary fixing at the time of manufacturing a display, and the like.
When the adhesive layer made of the hot melt type polysiloxane adhesive according to the embodiment of the present invention is peeled off from the adherend (adhesive material), it may be heated at a temperature equal to or higher than the glass transition temperature of the hot melt type polysiloxane adhesive. However, it is preferably heated at a glass transition temperature of + 30 ° C. or higher, more preferably at a glass transition temperature of + 40 ° C. or higher, for several minutes to several tens of minutes using a dryer or the like. Specifically, a method of heating an adhesive layer made of a hot-melt type polysiloxane adhesive having a glass transition temperature of about 40 ° C. at 80 ° C. for 30 minutes using, for example, a dryer can be mentioned.

Hereinafter, the present invention will be described in more detail with reference to Examples, but these descriptions do not limit the scope of the present invention. The data on the weight average molecular weight of the silicon compound in this example was obtained by GPC (gel permeation chromatography) using polystyrene having a known molecular weight as a standard substance. The glass transition temperature of the silicon compound is sampled using a thermomechanical analyzer: SII Nanotechnology Co., Ltd. (currently Hitachi High-Tech Science Co., Ltd.) "TMA / SS7100" using a needle-inserted probe. (A polymer thin film was prepared on a 5 mm x 5 mm quartz cell using the casting method, and the thickness was about 0.2 mm). The point where the position changed significantly was defined as Tg.

[Manufacturing Example 1]
Synthesis of Silicon Compound Represented by Formula (B) A silicon compound represented by the following formula (B) was synthesized according to the method described in paragraph 0083 of JP-A-2017-14320. The molecular weights of the obtained silicon compounds are shown in Tables 1 to 7.

In the table, the adhesives of all the examples are silicon compounds represented by the formula (B), and the weight average molecular weight (Mw), the average value of m, and the glass transition temperature (Tg) are as shown in the table. be.
In the table, the adhesive of Comparative Example 1-1 is a silicon compound represented by the formula (B), and the weight average molecular weight (Mw), the average value of m, and the glass transition temperature (Tg) are as shown in the table. Is.
In the table, PDMS is polydimethylsiloxane (DMS-32, manufactured by Gelest, Inc., weight average molecular weight (Mw) 36,000).
In the table, the silicone-based adhesive is (model number: KE-347T, manufactured by Shin-Etsu Chemical Co., Ltd.).

[500g load test]
A glass substrate having a length of about 40 mm, a width of 8 mm, and a thickness of 1 mm was ultrasonically cleaned with acetone for 30 minutes and chloroform for 30 minutes, dried, and then subjected to UV ozone treatment for 10 minutes, and the adherend (first substrate). Used as. An adhesive was placed on a region of 5 mm in length × 8 mm in width from the end of this glass substrate, and a portion of 5 mm in length × 8 mm in width was bonded from the end of another glass substrate of the same type and fixed with an eyeball clip. It was heated in an oven at 70 ° C. for 20 minutes, 100 ° C. for 20 minutes, and 200 ° C. for 2 hours. After heating, it was taken out from the oven, allowed to cool at room temperature for 5 minutes in the air atmosphere, and then the eyeball clip was removed to prepare a test piece. The thickness of the polymer (adhesive layer) was set to about 0.2 mm. The area of the polymer (adhesion area) was as shown in Table 1. A load of 500 g was applied to each test piece, and the time until the adhesive surface was peeled off was measured. The test temperature was room temperature of 25 to 27 ° C. The time required for peeling was 24 hours or more as “◯” and less than 24 hours as “x”. The results are shown in Table 1.

[20 kg load test]
A test piece was prepared in the same manner as in the 500 g load test except that the glass was changed to stainless steel. A load of 20 kg was applied to the test piece, and the time until the adhesive surface was peeled off was measured. The test temperature was room temperature of 25 to 27 ° C. The time required for peeling was "○" for 1 minute or more and "x" for less than 1 minute. The results are shown in Table 2.

[Tension shear test]
A test piece was prepared in the same manner as in the 500 g load test except that the glass was changed to stainless steel. The tensile shear stress was measured using the obtained test piece according to the method of JIS K6850. The tensile speed was 1 mm / min and the test temperature was room temperature of 25 to 27 ° C. The polymer thickness is shown in the table. The results are shown in Table 3.

[Evaluation of substrate adaptability]
Under the same conditions as in the 500 g load test, a test piece was prepared from stainless steel, silicon wafer, aluminum, hydrophobic glass, hydrophobic silicon wafer, and Teflon in addition to glass as a substrate. Hydrophobicization of hydrophobicized glass and hydrophobized silicon wafers was produced by immersing each substrate in hexamethyldisilazane for at least one day, taking it out, washing it with water, and firing it at 100 ° C. for 1 hour. The adhesive areas were all 40 mm ² .
Adhesion evaluation was made by holding both ends of the test piece and pulling it to peel it off. The test temperature was room temperature of 25 to 27 ° C. Unpeeled was marked with ◯, and peeled was marked with x. The results are shown in Table 4.

[Reversible adhesiveness test]
(1) The peeled test pieces of Examples 3-2 and 3-3 after the tensile shear test were overlapped again at the places where the resin was attached, and fixed with an eyeball clip. After heating in an oven at 70 ° C. for 20 minutes, 100 ° C. for 20 minutes, and 200 ° C. for 2 hours, the mixture was taken out of the oven and allowed to cool in an air atmosphere, and then the eyeball clips were removed. A test piece of Example 5-2 was prepared. The tensile shear test was performed again on the test piece reattached in this way. When the tensile shear stress was 5 MPa or more, it was evaluated as ◯, and when it was less than 5 MPa, it was evaluated as ×. The results of the tensile test are shown in Table 5.
(2) The test piece after bonding (Example 5-2) was peeled off by heating at 100 ° C., which is higher than the glass transition temperature of the polymer forming the adhesive layer, for 2 minutes. The test piece after bonding was easily peeled off by pulling it by hand by heating.
Then, with respect to the substrate which had been allowed to cool in an atmospheric atmosphere and reached room temperature, the portions to which the adhesive had adhered were overlapped again and adhered again under the above conditions to prepare a test piece of Example 5-3. The tensile shear test was performed again on the test pieces of Example 5-3. When the tensile shear stress was 5 MPa or more, it was evaluated as ◯, and when it was less than 5 MPa, it was evaluated as ×. The results of the tensile test are shown in Table 6.

[Transparency evaluation]
Length 50 mm, width 50 mm, with two glass thickness 0.7 mm, the adhesive comprising a polymer represented by the formula (B) (weight average molecular weight ^{(Mw): 11 × 10 4} , m ( average): After sandwiching 3.8) and pressing with an eyeball clip, the mixture was heated in an oven at 70 ° C. for 20 minutes, 100 ° C. for 20 minutes, and 200 ° C. for 2 hours. After heating, it was taken out from the oven and allowed to cool in the air atmosphere, and then the eyeball clip was removed to prepare a sample. The total light transmittance of this sample was measured using a haze meter (NDH 5000 manufactured by Nippon Denshoku Kogyo Co., Ltd.). The film thickness of the polymer (adhesive layer) was 200 μm. The reference used was a stack of two glasses of the same type of substrate. The total light transmittance of the sample was 91.8%.

From Tables 1 and 2, it can be seen that the adhesive layer made of the adhesive according to the present invention has a stronger adhesive force than the conventional silicone-based adhesive.
From Table 3, it can be seen that the adhesive layer according to the present invention has a large tensile shear stress.
From Table 4, it can be seen that the adhesive according to the present invention has strong adhesiveness to various base materials (adhesive materials) such as glass substrates and metals.
As shown in Tables 5 and 6, the adhesive layer made of the adhesive according to the present invention is heated above the glass transition temperature of the polymer forming the adhesive layer without being forcibly peeled off as in the tensile shear test. As a result, it can be easily peeled off. Further, the adhesive layer made of the adhesive according to the present invention has a strong tensile shear stress even after re-bonding, and can be easily peeled off by heating again at a temperature equal to or higher than the glass transition temperature.
Further, it was confirmed that the adhesive layer made of the adhesive according to the present invention has high transparency.

The adhesive layer made of the hot-melt type polysiloxane adhesive according to the present invention is very useful because it has high transparency, strong adhesive force to various adherends, and reversible adhesiveness. ..

Claims (9)

Represented by the following formula (A), seen containing a silicon compound having a glass transition temperature of 30 ° C. or higher 200 ° C. or less, can be reversibly detachable from the adherend at a temperature above the glass transition temperature of the silicon compound, a hot melt Type polysiloxane adhesive.

(In the formula (A), m independently represents an integer of 1-31; n represents an integer of 1 to 1,000; R ⁰ independently represents an aryl having 6 to 20 carbon atoms or 5 or 5 carbon atoms. Represents a cycloalkyl of 6; R ¹ and R ² independently represent hydrogen, an alkenyl having 2 to 40 carbon atoms, an alkyl having 1 to 40 carbon atoms, any hydrogen independently having a halogen or 1 to 20 carbon atoms. Represents an aryl having 6 to 20 carbon atoms which may be replaced by an alkyl, or an arylalkyl having 7 to 20 carbon atoms in which any hydrogen in the aryl may be independently replaced by a halogen or an alkyl having 1 to 20 carbon atoms. ;
In the alkyl having 1 to 40 carbon atoms, any hydrogen may be independently replaced by fluorine, and any −CH ₂ − is independently replaced by −O− or a cycloalkylene having 5 to 20 carbon atoms. May;
In the alkyl having 1 to 20 carbon atoms which is a substituent of aryl or arylalkyl, any hydrogen may be independently replaced with fluorine, and any −CH ₂ − is independently −.
It may be replaced with O-, cycloalkylene or phenylene having 5 to 20 carbon atoms;
In the arylalkyl alkylene, the number of carbon atoms is 1 to 10, any hydrogen may be independently replaced with fluorine, and any −CH ₂ − is independently −O−.
, -CH = CH- or cycloalkylene having 5 to 20 carbon atoms may be replaced. ) The hot melt type polysiloxane adhesive according to claim 1 ^{, wherein R 0} contains phenyl in the formula (A). The hot melt type polysiloxane adhesive according to claim 1 or 2 ^{, wherein R 1} and R ^{2 in the} formula (A) contain methyl or phenyl. The hot melt type polysiloxane adhesive according to any one of claims 1 to 3, wherein m is 1 or more and 10 or less on average in the formula (A). The hot melt type polysiloxane adhesive according to any one of claims 1 to 4, wherein the glass transition temperature of the silicon compound is 30 ° C. or higher and 180 ° C. or lower. The hot melt type polysiloxane adhesive according to any one of claims 1 to 5 , which can be adhered to a glass, a silicon wafer, a metal, a metal oxide, a plastic film or a hydrophobic substrate. The hot melt type polysiloxane adhesive according to any one of claims 1 to 6 , which is substantially free of a curing agent. The hot melt type polysiloxane adhesive according to any one of claims 1 to 7 , further comprising an inorganic filler. The hot-melt type polysiloxane adhesive according to any one of claims 1 to 7 , which does not substantially contain a component other than the silicon compound.