JP6792850B2 - Polymer material whose morphology can be controlled by light stimulation - Google Patents

Description

The present invention relates to a polymer capable of controlling a fluid state and a non-fluid state depending on the presence or absence of light stimulation, and a method for controlling the fluidity of the polymer.

In stereolithography and adhesives, thermosetting resins, photocurable resins and the like are used as materials whose fluidity changes due to external stimuli. However, these materials have a problem that a dedicated device is required for the curing process, and once processed, reprocessing is difficult and the material is poorly recyclable.

On the other hand, a substance that does not contain a solvent and can reversibly switch the fluidity between a solid and a liquid by an external stimulus at room temperature is expected to be applied to not only environmentally friendly but also reusable resins and adhesives. Will be done. As one of such attempts, a compound that can be fluidized or non-fluidized by light stimulation has been reported, and its application to an adhesive or the like has been studied (for example, Patent Document 1 and Non-Patent Document 1). However, the change in the flow state in Patent Document 1 merely obtains the flow state by reducing the crystallinity of regularly arranged molecules by photostimulation, and is expected to have high strength and adhesiveness as a material. It was not possible, and the range of molecular structure design was limited. Further, since the compound of Patent Document 1 uses the photoisomerization reaction of azobenzene, it is necessary to change the wavelength range of the irradiated light in order to control the fluidity.

On the other hand, as a mode of the adhesive, generally, a reaction type, a solvent type, an aqueous type, a hot melt type, a pressure sensitive type and the like are known, and among these, the hot melt type adhesive is a hot melt type adhesive. Most widely used for bonding metal materials. Such a hot melt type adhesive can be applied to a material in a fluid state by heating and melting the adhesive, and then cooled to solidify the adhesive so that the materials can be bonded to each other. The bonding method using the hot melt type adhesive has advantages that it is highly safe because it does not contain an organic solvent and that it can be applied to a material in a molten state, so that various application patterns can be used. However, since the adhesive is melted at a high temperature and used, there are problems that it is not suitable for adhesion in an environment where heating is not desirable or for adhesion between materials having low heat resistance.

Japanese Unexamined Patent Publication No. 2011-256291

Adv. Mater. , 2012, 24, 2353-2356

Therefore, the present invention is a novel polymer capable of controlling a fluid state and a non-fluid state by light stimulation, and more specifically, a high polymer having a property of being able to reversibly repeat a liquid state and a solid state by light stimulation. It is an object of the present invention to develop a molecule and to provide a method for controlling the fluidity of such a polymer by light stimulation.

As a result of diligent studies to solve the above problems, the present inventor has broken the covalent bond by photostimulation, and when the photostimulation is not applied, the bond is crosslinked by a photoresponsive functional group that reforms. We have found that the flow state of the crosslinked polymer can be controlled by reversibly changing the molecular shape depending on the presence or absence of photostimulation by using a molecule, and have completed the present invention.

（式中、Ｒは、カルボン酸エステル基であり；ｎは、２〜２００の整数であり;４つの分岐鎖はいずれも同じ構造を有している。）
又は、以下の構造を有する四分岐型ポリシロキサン

（式中、Ｒは、水素またはアルキル基；ｎは、２〜２００の整数であり;４つの分岐鎖はいずれも同じ構造を有している。）
である、上記（１）に記載の架橋高分子
を提供するものである。 That is, the present invention, in one aspect,
(1) A crosslinked polymer obtained by cross-linking a precursor polymer, wherein the precursor polymer is a polymer in which a loffin group is introduced at at least one terminal of a skeletal polymer; The loffin group in the precursor polymer has a structure in which the crosslinks are crosslinked between the molecules by covalent bonding; the crosslinked polymer can be reversibly changed from a solid state to a liquid state by cleaving the crosslinks by photostimulation. The crosslinked polymer, characterized in that;
(2) The crosslinked polymer according to (1) above, wherein the light stimulus is irradiation with ultraviolet rays;
(3) The crosslinked polymer according to (1) or (2) above, which returns to a solid state by stopping the photostimulation;
(4) The crosslinked polymer according to any one of (1) to (3) above, wherein the skeletal polymer is a polyacrylate or a polysiloxane;
(5) The crosslinked polymer according to (4) above, wherein the skeletal polymer is a polyacrylate having a quaternary structure or a polysiloxane having a quaternary structure;
(6) The crosslinked polymer according to (5) above, which has a loffin group at all terminals of the polyacrylate having a tetrabranched structure;
(7) The crosslinked polymer according to any one of (1) to (6) above, wherein the skeletal polymer has a molecular weight in the range of 1,000 to 100,000;
(8) The crosslinked polymer according to any one of (1) to (7) above, wherein the skeletal polymer has a glass transition temperature in the range of −130 ° C. to 30 ° C.; and (9) the precursor height. Quadrant polyacrylate whose molecule has the following structure

(In the formula, R is a carboxylic acid ester group; n is an integer of 2 to 200; all four branched chains have the same structure.)
Alternatively, a tetrabranched polysiloxane having the following structure

(In the formula, R is a hydrogen or alkyl group; n is an integer of 2 to 200; all four branched chains have the same structure.)
The crosslinked polymer according to the above (1) is provided.

（式中、Ｒは、カルボン酸エステル基であり；ｎは、２〜２００の整数であり;４つの分岐鎖はいずれも同じ構造を有している。）
又は、以下の構造を有する四分岐型ポリシロキサン

（式中、Ｒは、水素またはアルキル基；ｎは、２〜２００の整数であり;４つの分岐鎖はいずれも同じ構造を有している。）
である、上記（１０）に記載の化合物；
を提供するものであり、及び
（１７）上記（１０）〜（１６）のいずれか１に記載の化合物が、前記ロフィン基において分子間又は分子内で架橋してなる、架橋高分子
を提供するものである。 In another aspect, the present invention also covers a polymer compound that is a precursor of the crosslinked polymer. That is, the present invention
(10) A compound having a loffin group at at least one terminal of a skeletal polymer, which is in a liquid state at room temperature;
(11) The compound according to (10) above, wherein the skeletal polymer is a polyacrylate or a polysiloxane;
(12) The compound according to (11) above, wherein the skeletal polymer is a polyacrylate having a quaternary structure or a polysiloxane having a quaternary structure;
(13) The compound according to (12) above, which has a loffin group at all terminals of the polyacrylate having a tetrabranched structure.
(14) The compound according to any one of (10) to (13) above, wherein the skeletal polymer has a molecular weight in the range of 1,000 to 100,000;
(15) The compound according to any one of (10) to (14) above, wherein the skeletal polymer has a glass transition temperature in the range of −130 ° C. to 30 ° C.;
(16) Quadrant polyacrylate having the following structure

(In the formula, R is a carboxylic acid ester group; n is an integer of 2 to 200; all four branched chains have the same structure.)
Alternatively, a tetrabranched polysiloxane having the following structure

(In the formula, R is a hydrogen or alkyl group; n is an integer of 2 to 200; all four branched chains have the same structure.)
The compound according to (10) above;
(17) Provided is a crosslinked polymer in which the compound according to any one of (10) to (16) above is crosslinked at the loffin group between and within the molecule. It is a thing.

（式中、Ｒは、カルボン酸エステル基であり；ｎは、２〜２００の整数であり;４つの分岐鎖はいずれも同じ構造を有している。）
又は、以下の構造を有する四分岐型ポリシロキサン

（式中、Ｒは、水素またはアルキル基；ｎは、２〜２００の整数であり;４つの分岐鎖はいずれも同じ構造を有している。）
である、上記（１８）に記載の方法
を提供するものである。 Further, in a further aspect, the present invention provides a method for reversibly controlling the fluidity of a polymer material using the crosslinked polymer. That is, the present invention
(18) A method for reversibly controlling the fluidity of a polymer material, in which a liquid precursor polymer having a loffin group introduced at at least one end of the skeleton polymer is crosslinked between the molecules. A step of obtaining a crosslinked polymer in a solid state, wherein the crosslinked polymer has a structure in which the loffin group in the precursor polymer is intermolecularly crosslinked by a covalent bond; The method comprising the step of cleaving the crosslinked polymer by applying a stimulus to change the crosslinked polymer from a solid state to a liquid state;
(19) The method according to (18) above, wherein the light stimulus is irradiation with ultraviolet rays;
(20) The method according to (18) or (19) above, further comprising a step of returning to a solid state by stopping the photostimulation;
(21) The method according to any one of (18) to (20) above, wherein the cross-linking is performed in the presence of a base;
(22) In the step of obtaining the cross-linked polymer in the solid state, a photostimulus is applied to the precursor polymer in which the loffin group is cross-linked in the molecule to cleave the cross-linking in the molecule, and then the precursor polymer is released. The method according to any one of (18) to (21) above, which is a step of obtaining a crosslinked polymer in a solid state by cross-linking between molecules;
(23) The method according to any one of (18) to (22) above, wherein the skeletal polymer is a polyacrylate or a polysiloxane;
(24) The method according to (23) above, wherein the skeletal polymer is a polyacrylate having a quaternary structure or a polysiloxane having a quaternary structure, which is the compound according to the above (11);
(25) The method according to (24) above, wherein the polyacrylate having the tetrabranched structure has a loffin group at all ends;
(26) The method according to any one of (18) to (25) above, wherein the skeletal polymer has a molecular weight in the range of 1,000 to 100,000;
(27) The method according to any one of (18) to (26) above, wherein the skeletal polymer has a glass transition temperature in the range of −130 ° C. to 30 ° C.; and (28) the precursor polymer is Quadrant polyacrylate having the following structure

(In the formula, R is a carboxylic acid ester group; n is an integer of 2 to 200; all four branched chains have the same structure.)
Alternatively, a tetrabranched polysiloxane having the following structure

(In the formula, R is a hydrogen or alkyl group; n is an integer of 2 to 200; all four branched chains have the same structure.)
The method according to (18) above is provided.

The present invention also provides, in another embodiment, an adhesive containing the above-mentioned crosslinked polymer and an adhesive method using the same. That is, the present invention
(29) An adhesive containing the crosslinked polymer according to any one of (1) to (9) above;
(30) The adhesive according to (29) above, which is a hot melt type adhesive;
(31) A material having the crosslinked polymer according to any one of (1) to (9) above on the surface;
(32) A method for adhering materials, which comprises adhering and detaching two or more materials using the method according to any one of (18) to (28) above; and (33) (1) above. A resin material for a 3D printer containing the crosslinked polymer according to any one of (9).
Also related to.

Conventional substances whose flow state can be controlled by light stimulation utilize the difference in the crystal state of molecules to change the flow state, so that the range of molecular design is significantly limited. On the other hand, the present invention changes the flow state between a solid and a liquid by introducing a functional group capable of reversible cleavage (crosslinking / decrosslinking) of a covalent bond that can be cleaved / reformed by photostimulation. Can be controlled. Therefore, since such a functional group can be introduced into an arbitrary skeletal structure, the applicable range is remarkably wider than that of the conventional material, and a desired material can be provided according to various uses. Further, in the present invention, since the covalent bond can be cleaved and reformed only by the on-off operation of the light stimulus, the light irradiated when controlling the fluidity as in the conventional technique using the intramolecular photoisomerization reaction. There is no need to change the wavelength range of.

Further, in the present invention, since the flow state can be changed from a solid to a liquid only by light stimulation without heating or the like, heating is not desirable without impairing the convenience of the existing hot melt type adhesive. It has the effect of being applicable to adhesion between materials with low heat resistance. Further, when the crosslinked polymer of the present invention is used as a resin material for a 3D printer, even after being molded once, fine adjustment can be performed again by applying a light stimulus.

Hereinafter, embodiments of the present invention will be described. The scope of the present invention is not limited to these explanations, and other than the following examples, the scope of the present invention can be appropriately modified and implemented without impairing the gist of the present invention.

1. 1. Crosslinked polymer The crosslinked polymer of the present invention has a structure in which a precursor polymer in which a loffin group is introduced at at least one end of a skeletal polymer is crosslinked between the molecules by a covalent bond. Here, the precursor polymer is a compound having fluidity at room temperature, that is, in a liquid state, and by cross-linking between the molecules, a solid crosslinked polymer having non-fluidity can be obtained.

Then, by applying a light stimulus to the crosslinked polymer, the crosslinked (covalent bond) in the loffin group is cleaved, and the solid state can be changed to the liquid state again. Further, by stopping the photostimulation and leaving it at room temperature, cross-linking is spontaneously formed again, and the cross-linked polymer can be returned to the solid state. By utilizing such a reaction, the fluidity of the crosslinked polymer can be reversibly controlled by photostimulation.

The light stimulus used in the present invention is preferably irradiation with ultraviolet rays. The wavelength range of ultraviolet rays is 10 to 400 nm, preferably 200 to 400 nm, and more preferably 315 to 400 nm. Further, it is preferable to apply the light stimulus under a temperature condition of 10 to 60 ° C.

As described above, the skeletal polymer constituting the main chain of the precursor polymer used in the present invention is in a fluid state at room temperature. As the skeleton polymer, those known in the art can be used, for example, polyacrylate-based polymer, polymethacrylate-based polymer, polystyrene-based polymer, polyethylene-based polymer, polyamide-based polymer, polyester-based polymer, polyurethane-based polymer. A polymer, a polysiloxane-based polymer, or the like can be used. Preferably, it is polyacrylate or polysiloxane. More preferably, it is poly (alkylaclate) or polydimethylsiloxane (PDMS). Further, as the skeleton polymer, not only a linear polymer but also a polymer having a branched structure can be used, and a polyacrylate having a quaternary structure or a polysiloxane having a quaternary structure is preferably used. be able to.

Further, from the viewpoint that the skeletal polymer is in a fluid state at room temperature, the molecular weight is preferably in the range of 1,000 to 500,000, more preferably in the range of 3,000 to 100,000 (number average). Molecular weight). Similarly, it preferably has a glass transition temperature (Tg) in the range of −130 ° C. to 30 ° C., more preferably −130 ° C. to 0 ° C.

In the precursor polymer used in the present invention, a loffin group is introduced into at least one terminal of the above-mentioned skeletal polymer. The loffin group is a 2,4,5-triphenylimidazole group and has the following structure.

Each phenyl group in the loffin group may be independently substituted, for example, a halogen atom, an alkyl group which may be substituted respectively, an alkenyl group, an aryl group, a sulfo group, a carboxyl group, an ester group, an amide. It may be substituted with the same or different substituents 1 to 5 selected from the group consisting of groups. In the present specification, "alkyl" may be any of linear, branched chain, cyclic, or an aliphatic hydrocarbon group consisting of a combination thereof. The number of carbon atoms of the alkyl group is not particularly limited, but for example, the number of carbon atoms is 1 to 20 (C _{1 to 20} ), the number of carbon atoms is 3 to 15 (C 3 to ₁₅ ), and the number of carbon atoms is 5 to 10 (C _{5 to} 10). ). In the present specification, "aryl" may be either a monocyclic or condensed polycyclic aromatic hydrocarbon group, and as a ring-constituting atom, a hetero atom (for example, an oxygen atom, a nitrogen atom, or a sulfur atom) may be used. Etc.) may be an aromatic heterocycle containing one or more. In this case, it may be referred to as "heteroaryl" or "heteroaromatic". Whether the aryl is a monocyclic ring or a condensed ring, it can be bonded at all possible positions.

The loffin group is introduced into at least one terminal of the skeletal polymer, but preferably two or more. For example, in the case of a polyacrylate having a tetra-branched structure, a loffin group can be introduced at the end of each of the four branched chains. The number of such loffin groups can be changed according to the desired physical properties of the crosslinked polymer.

Non-limiting specific examples of the precursor polymer used in the present invention include the following tetra-branched polyacrylate having a loffin group at the terminal.

In the formula, R is a carboxylic acid ester group, preferably -COOME, -COOEt, -COOBu, -COOHex, and more preferably -COOBu. n is an integer of 2 to 200, preferably 2 to 20. Although all four branched chains in the formula have the same structure, it is not always necessary to have a loffin group at the end of all the branched chains as described above. Further, the length of the branched chain, that is, the value of n does not necessarily have to be the same in each branched chain, and may be different.

Using such a tetrabranched polyacrylate as a precursor polymer, the crosslinked molecule crosslinked between the molecules at the loffin group has the following structure.

Further, as a further non-limiting specific example of the precursor polymer used in the present invention, the following tetrabranched polysiloxane having a loffin group at the terminal can be mentioned.

In the formula, R is a hydrogen or alkyl group, preferably methyl. n is an integer of 2 to 200, preferably 2 to 20. Although all four branched chains in the formula have the same structure, it is not always necessary to have a loffin group at the end of all the branched chains as described above. Further, the length of the branched chain, that is, the value of n does not necessarily have to be the same in each branched chain, and may be different.

2. 2. Flow Control Method In another embodiment, the present invention reversibly controls the fluidity of a polymer material by utilizing the reaction of cross-linking and cleavage by photostimulation between the precursor polymer and the cross-linked polymer described above. Also related to the method.

More specifically, the method of the present invention
<Step 1> A step of obtaining a solid-state crosslinked polymer by cross-linking a liquid-state precursor polymer having a loffin group introduced at at least one terminal of the skeletal polymer between molecules, and <Step 2> solid. It is characterized by including a step of cleaving the crosslinked polymer by applying a light stimulus to the crosslinked polymer in the state and changing the crosslinked polymer from a solid state to a liquid state.

In the above step 1, the crosslinked polymer has a structure in which the terminal loffin groups of the precursor polymer are crosslinked between the molecules by covalent bonds as described above. The precursor polymer is a compound in a liquid state having fluidity at room temperature, and when this is crosslinked between molecules, a solid crosslinked polymer having immobility can be obtained. Then, in step 2, the crosslink (covalent bond) in the loffin group is cleaved by photostimulation, and the solid state can be changed to the liquid state again.

The cross-linking reaction in step 1 can proceed under normal conditions in the art, but is preferably in the presence of bases such as sodium hydroxide, potassium hydroxide, calcium hydroxide, and oxidizing agents such as potassium ferricyanide. Will be done.

The light stimulation in step 2 is preferably irradiation with ultraviolet rays, and the details thereof are as described above.

Moreover, the method of this invention
<Step 3> A step of returning to a solid state by stopping the light stimulation can be further included.

In step 3, by stopping the photostimulation and leaving it at room temperature, cross-linking is spontaneously formed again, and the cross-linked polymer can be returned to the solid state. By repeating these steps 2 and 3, the fluidity of the crosslinked polymer can be reversibly controlled.

Further, as another embodiment in step 1, a photostimulus is applied to a precursor polymer in which a loffin group is crosslinked in the molecule to cleave the cross-linking in the molecule, and then the precursor polymer is cross-linked between the molecules. It can also be a step of obtaining a crosslinked polymer in a solid state.

That is, when a precursor polymer having a lofin group at a plurality of terminals is crosslinked under low concentration conditions, a compound having an intramolecular crosslinked structure is produced, but since the compound is a liquid having fluidity at room temperature, this is used. It can be used in place of the precursor polymer (monomer) described above. Such a compound having an intramolecular crosslinked structure is preferable when it is desired to provide the crosslinked polymer of the present invention in a non-fluid state. As a non-limiting example, when the precursor polymer is a quaternary polyacrylate, the reaction from the compound having an intramolecular crosslinked structure to the crosslinked polymer (crosslinked between molecules) is as follows.

3. 3. Applications The crosslinked polymer of the present invention has the property of being able to control the flow state of a solid-liquid by light stimulation, and is therefore suitable as an adhesive or a resin material for a 3D printer. Therefore, the present invention also covers an adhesive containing the crosslinked polymer or a resin material for a 3D printer. As the adhesive, a hot melt type adhesive is preferable. The adhesive containing the crosslinked polymer of the present invention has an advantage that it can be applied to adhesion in an environment where heating is not desirable and adhesion between materials having low heat resistance.

Further, a method for adhering materials, which comprises adhering and desorbing two or more materials by using the method including the above-mentioned steps 1 to 3, is also an object of the present invention. When used as such an adhesive, if it is preferable to provide it as an adhesive in a solid state, a crosslinked polymer crosslinked between molecules can be provided as it is. In this case, at the time of use, a plurality of materials can be adhered by irradiating with light, temporarily making it in a liquid state, applying it to a desired material, and then solidifying it. Such an embodiment is preferable when it is preferable to avoid the outflow of the adhesive during transportation or when it is convenient to hold and handle the adhesive in the hand.

On the other hand, when it is preferable to provide it in a liquid state, it is provided in the form of a compound in which the above-mentioned precursor polymer is cross-linked in the molecule, and the intramolecular cross-linked compound is applied to a desired material and solidified to obtain a plurality of compounds. Materials can also be glued together. Such an embodiment is suitable when it is necessary to pour into a narrow place or when the application is to pour into a mold.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto.

1. 1. Synthesis of precursor polymer A tetrabranched polyacrylate having a loffin group at the terminal was synthesized as shown below.

ペンタエリスリトールテトラキス（２−ブロモイソブチレート）（５．０ ｇ）、アクリル酸ブチル（１２．３ｍＬ）、臭化銅（Ｉ)（３９０ｍｇ）、４，４’−ジノニル−２，２’−ビピリジル（２．２３ｇ）、及びトルエン（１２ｍＬ）を混合し、８０℃で４時間、原子移動ラジカル重合を行った。反応混合物のアルミナカラムカラムクロマトグラフィによる精製を経て四分岐構造を有する末端臭素型ポリ（ブチルアクリレート）を１０．７ｇ得た。分子量（Ｍｎ）は、２３００であった。 Step a: Terminal bromine type poly (butyl acrylate) (Compound 1)

Pentaerythritol tetrakis (2-bromoisobutyrate) (5.0 g), butyl acrylate (12.3 mL), copper (I) bromide (390 mg), 4,4'-dinonyl-2,2'-bipyridyl (2.23 g) and toluene (12 mL) were mixed, and atom transfer radical polymerization was carried out at 80 ° C. for 4 hours. The reaction mixture was purified by alumina column column chromatography to obtain 10.7 g of terminal bromine-type poly (butyl acrylate) having a quaternary structure. The molecular weight (Mn) was 2300.

By changing the amount of the monomer used for the polymerization, it was synthesized in the same manner as the terminal bromine type poly (butyl acrylate) having a different molecular weight.

四分岐構造を有する末端臭素型ポリ（ブチルアクリレート）（５．４ｇ）、アジ化ナトリウム（２．３ｇ）、及びＮ，Ｎ−ジメチルホルムアミド（１５ｍＬ）を混合し、室温で１４時間攪拌した。反応混合物を多量の水に加え、クロロホルムによる抽出を経て、四分岐構造を有する末端アジド型ポリ（ブチルアクリレート）を５．２ｇ得た。 Step b: Terminal azide type poly (butyl acrylate) (Compound 2)
Sodium azide was allowed to act as an endcapping agent on compound 1 obtained in step a to obtain compound 2.

Terminal bromine-type poly (butyl acrylate) having a quaternary structure (5.4 g), sodium azide (2.3 g), and N, N-dimethylformamide (15 mL) were mixed and stirred at room temperature for 14 hours. The reaction mixture was added to a large amount of water and extracted with chloroform to obtain 5.2 g of a terminal azide-type poly (butyl acrylate) having a tetrabranched structure.

四分岐構造を有する末端アジド型ポリ（ブチルアクリレート）（３．８ ｇ）、２−（４’−プロピニルオキシフェニル）−４，５−ジフェニルイミダゾール（２．２ｇ）、臭化銅（Ｉ)（８８９ｍｇ）、Ｎ，Ｎ，Ｎ’，Ｎ’’，Ｎ’’−ペンタメチルジエチレントリアミン（１．３ｍＬ）、及びＮ，Ｎ−ジメチルホルムアミド（２０ｍＬ）を混合し、室温で3時間攪拌した。反応混合物のアルミナカラムカラムクロマトグラフィによる精製を経て四分岐構造を有する末端ロフィン型ポリ（ブチルアクリレート）を３．０ｇ得た。 Step c: C-terminal loffin type poly (butyl acrylate) (Compound 3)
A compound 3 having a loffin group introduced at the terminal was obtained by a Husgen cycloaddition reaction between the compound 2 obtained in step b and a loffin derivative.

Terminal azide-type poly (butyl acrylate) having a tetrabranched structure (3.8 g), 2- (4'-propynyloxyphenyl) -4,5-diphenylimidazole (2.2 g), copper bromide (I) ( 889 mg), N, N, N', N'', N''-pentamethyldiethylenetriamine (1.3 mL), and N, N-dimethylformamide (20 mL) were mixed and stirred at room temperature for 3 hours. The reaction mixture was purified by alumina column column chromatography to obtain 3.0 g of a terminal loffin type poly (butyl acrylate) having a tetrabranched structure.

四分岐型構造を有する末端ロフィン型ポリ（ブチルアクリレート）（１．９５ｇ）のトルエン溶液（２０ｍＬ）に、水（３０ｍＬ）、水酸化ナトリウム（１．１２ｇ）、及びフェリシアン化カリウム（６．５８ｇ）を加え、０℃で３０分間激しく攪拌した。反応混合物の有機層を水で洗浄したのちに濃縮し、減圧で乾燥させることで架橋高分子を１．４４ｇ得た。 2. 2. Synthesis of Crosslinked Polymer The compound 3 obtained in step c was crosslinked between the molecules to obtain a crosslinked polymer (compound 4).

Water (30 mL), sodium hydroxide (1.12 g), and potassium ferricyanide (6.58 g) are added to a toluene solution (20 mL) of terminal loffin poly (butyl acrylate) (1.95 g) having a tetrabranched structure. In addition, the mixture was vigorously stirred at 0 ° C. for 30 minutes. The organic layer of the reaction mixture was washed with water, concentrated, and dried under reduced pressure to obtain 1.44 g of a crosslinked polymer.

3. 3. Adhesion and peeling test 10 mg of crosslinked polymer (Compound 4) was sandwiched between two slide glasses and irradiated with ultraviolet rays (365 nm) for 1 minute. The crosslinked polymer changed to a liquid state by irradiation with ultraviolet rays, but when it was allowed to stand for 5 minutes, it was confirmed that the two slide glasses adhered well via the solidified crosslinked polymer.
Further, when the adhesive portion of the slide glass was irradiated with ultraviolet rays for 1 minute, the crosslinked polymer became liquid again and the two slide glasses were peeled off.

4. Synthesis of precursor polymer (PDMS) In addition, a tetrabranched polysiloxane having a loffin group at the terminal was synthesized as shown below.

ペンタエリスリトール（２５５ｍｇ）、ヘキサメチルシクロトリシロキサン（３．３４ｇ）、Ｎ,Ｎ−ジメチルホルムアミド（２０ｍＬ）、テトラヒドロフラン（１０ｍＬ）を混合したのちに、１,５,７−トリアザビシクロ［４．４．０］デカ−５−エン（１０ｍｇ）のＴＨＦ溶液（１ｍＬ）を加え、室温で３０分攪拌した。次いで、反応混合物にヘキサメチルシクロトリシロキサン（１３．４ｇ）のトルエン溶液（４０ｍＬ）を加え２２時間攪拌した。反応混合物にトリエチルアミン（１１ｍＬ）を加えて３分間攪拌した後に、クロロジメチルシラン（４．１７ｍＬ）を加えてさらに３０分間攪拌した。反応混合物の抽出操作による精製を経て四分岐構造を有する末端水素型ポリ（ジメチルシロキサン）を１１．２ｇ得た。分子量（Ｍｎ）は、１０５００であった。 Step a: Terminal hydrogen type poly (dimethylsiloxane) (Compound 5)

After mixing pentaerythritol (255 mg), hexamethylcyclotrisiloxane (3.34 g), N, N-dimethylformamide (20 mL) and tetrahydrofuran (10 mL), 1,5,7-triazabicyclo [4.4] 0.0] A solution of deca-5-ene (10 mg) in THF (1 mL) was added, and the mixture was stirred at room temperature for 30 minutes. Then, a toluene solution (40 mL) of hexamethylcyclotrisiloxane (13.4 g) was added to the reaction mixture, and the mixture was stirred for 22 hours. Triethylamine (11 mL) was added to the reaction mixture and the mixture was stirred for 3 minutes, then chlorodimethylsilane (4.17 mL) was added and the mixture was further stirred for 30 minutes. After purification by an extraction operation of the reaction mixture, 11.2 g of terminal hydrogen type poly (dimethylsiloxane) having a quaternary structure was obtained. The molecular weight (Mn) was 10500.

四分岐構造を有する末端水素型ポリ（ジメチルシロキサン）（５．８ｇ）、４−アリルオキシベンズアルデヒド（１．７ｍＬ）、トルエン（２０ｍＬ）を混合した後に、白金(０) −１,３−ジビニル−１,１,３,３−テトラメチルジシロキサン錯体のキシレン溶液（５０μＬ）を加え７０℃で２．５時間攪拌した。反応混合物の抽出操作による精製を経て四分岐構造を有する末端アルデヒド型ポリ（ジメチルシロキサン）を４．９ｇ得た。 Step b: Terminal aldehyde type poly (dimethylsiloxane) (Compound 6)
4-allyloxybenzaldehyde was allowed to act on the compound 5 obtained in step a to obtain compound 6.

After mixing terminal hydrogen type poly (dimethylsiloxane) (5.8 g) having a tetrabranched structure, 4-allyloxybenzaldehyde (1.7 mL), and toluene (20 mL), platinum (0) -1,3-divinyl- A xylene solution (50 μL) of 1,1,3,3-tetramethyldisiloxane complex was added, and the mixture was stirred at 70 ° C. for 2.5 hours. Purification by an extraction operation of the reaction mixture gave 4.9 g of a terminal aldehyde-type poly (dimethylsiloxane) having a tetrabranched structure.

四分岐構造を有する末端アルデヒド型ポリ（ジメチルシロキサン）（４．０ ｇ）、ベンジル（３．１ｇ）、酢酸アンモニウム（３．４ｇ）、トルエン（１０ｍＬ）、及びメタノール（１０ｍＬ）を混合し、７０℃で４時間攪拌した。反応混合物の抽出操作による精製を経て四分岐構造を有する末端ロフィン型ポリ（ジメチルシロキサン）を２．５ｇ得た。 Step c: Terminal loffin type poly (dimethylsiloxane) (Compound 7)
By reacting the compound 6 obtained in step b with benzyl, a compound 8 having a loffin group introduced at the terminal was obtained.

A terminal aldehyde type poly (dimethylsiloxane) (4.0 g) having a quaternary structure, benzyl (3.1 g), ammonium acetate (3.4 g), toluene (10 mL), and methanol (10 mL) are mixed and 70. The mixture was stirred at ° C. for 4 hours. After purification by an extraction operation of the reaction mixture, 2.5 g of terminal loffin type poly (dimethylsiloxane) having a quaternary structure was obtained.

四分岐型構造を有する末端ロフィン型ポリ（ジメチルシロキサン）（１．３５ｇ）のヘキサン溶液（１０ｍＬ）に、水（３０ｍＬ）、水酸化ナトリウム（１．２６ｇ）、及びフェリシアン化カリウム（７．４１ｇ）を加え、室温で６０分間激しく攪拌した。反応混合物の有機層を水で洗浄したのちに濃縮し、減圧で乾燥させることで架橋高分子を１．３２ｇ得た。 5. Synthesis of Crosslinked Polymer The compound 8 obtained in step c was crosslinked between the molecules to obtain a crosslinked polymer (compound 9).

Water (30 mL), sodium hydroxide (1.26 g), and potassium ferricyanide (7.41 g) were added to a hexane solution (10 mL) of terminal lofin-type poly (dimethylsiloxane) (1.35 g) having a tetrabranched structure. In addition, it was vigorously stirred at room temperature for 60 minutes. The organic layer of the reaction mixture was washed with water, concentrated, and dried under reduced pressure to obtain 1.32 g of a crosslinked polymer.

Claims (31)

A cross-linked polymer formed by cross-linking a precursor polymer.
The precursor polymer is a polymer in which a lofin group is introduced at at least one end of a skeletal polymer;
The crosslinked polymer has a structure in which the loffin group in the precursor polymer is crosslinked between molecules by a covalent bond;
The crosslinked polymer is characterized in that the crosslinked polymer is cleaved by light stimulation and can be reversibly changed from a solid state to a liquid state. The crosslinked polymer according to claim 1, wherein the light stimulus is irradiation with ultraviolet rays. The crosslinked polymer according to claim 1 or 2, wherein the solid state is restored by stopping the photostimulation. The crosslinked polymer according to any one of claims 1 to 3, wherein the skeletal polymer is a polyacrylate or a polysiloxane. The crosslinked polymer according to claim 4, wherein the skeletal polymer is a polyacrylate having a quaternary structure or a polysiloxane having a quaternary structure. The crosslinked polymer according to claim 5, which has a loffin group at all terminals of the polyacrylate having a tetrabranched structure. The crosslinked polymer according to any one of claims 1 to 6, wherein the skeletal polymer has a number average molecular weight in the range of 1,000 to 100,000. The crosslinked polymer according to any one of claims 1 to 7, wherein the skeletal polymer has a glass transition temperature in the range of −130 ° C. to 0 ° C. A tetrabranched polyacrylate in which the precursor polymer has the following structure

(In the formula, R is a carboxylic acid ester group; n is an integer of 2 to 200; all four branched chains have the same structure.)
Alternatively, a tetrabranched polysiloxane having the following structure

(In the formula, R is a hydrogen or alkyl group; n is an integer of 2 to 200; all four branched chains have the same structure.)
The crosslinked polymer according to claim 1. A compound in a liquid state at room temperature having a loffin group at at least one terminal of the skeletal polymer , wherein the skeletal polymer is a polyacrylate having a quaternary structure or a polysiloxane having a quaternary structure . The compound according to claim 10 , which has a loffin group at all terminals of the polyacrylate having a tetrabranched structure. The compound according to claim 10 or 11 , wherein the skeletal polymer has a number average molecular weight in the range of 1,000 to 100,000. The compound according to any one of claims 10 to 12 , wherein the skeletal polymer has a glass transition temperature in the range of −130 ° C. to 0 ° C. Quadrant polyacrylate having the following structure

(In the formula, R is a carboxylic acid ester group; n is an integer of 2 to 200; all four branched chains have the same structure.)
Alternatively, a tetrabranched polysiloxane having the following structure

(In the formula, R is a hydrogen or alkyl group; n is an integer of 2 to 200; all four branched chains have the same structure.)
The compound according to claim 10. A crosslinked polymer obtained by cross-linking the compound according to any one of claims 10 to 14 between or within the molecules at the loffin group. A method of reversibly controlling the fluidity of a polymer material.
A step of obtaining a solid-state crosslinked polymer by cross-linking a liquid-state precursor polymer having a loffin group introduced at at least one terminal of the skeleton polymer between the molecules, wherein the crosslinked polymer is described above. The loffin group in the precursor polymer has a structure in which the crosslinks are crosslinked between the molecules by a covalent bond; and the crosslinks are cleaved by applying a photostimulation to the crosslinked polymer in a solid state, so that the crosslinked polymer is in a solid state. The method comprises the steps of bringing the material into a liquid state. 16. The method of claim 16 , wherein the light stimulus is irradiation of ultraviolet light. The method according to claim 16 or 17 , further comprising a step of returning to a solid state by stopping the photostimulation. The method according to any one of claims 16 to 18 , wherein the cross-linking is performed in the presence of a base. In the step of obtaining the cross-linked polymer in the solid state, a photostimulus is applied to the precursor polymer in which the loffin group is cross-linked in the molecule to cleave the cross-linking in the molecule, and then the precursor polymer is intermolecularly transferred. The method according to any one of claims 16 to 19 , which is a step of obtaining a crosslinked polymer in a solid state by cross-linking. The method according to any one of claims 16 to 20 , wherein the skeletal polymer is a polyacrylate or a polysiloxane. The method according to claim 21 , wherein the skeletal polymer is a polyacrylate having a quaternary structure or a polysiloxane having a quaternary structure. 22. The method of claim 22 , wherein the polyacrylate having a tetrabranched structure has a loffin group at all ends. The method according to any one of claims 16 to 23 , wherein the skeletal polymer has a number average molecular weight in the range of 1,000 to 100,000. The method according to any one of claims 16 to 24 , wherein the skeletal polymer has a glass transition temperature in the range of −130 ° C. to 0 ° C. A tetrabranched polyacrylate in which the precursor polymer has the following structure

(In the formula, R is a carboxylic acid ester group; n is an integer of 2 to 200; all four branched chains have the same structure.)
Alternatively, a tetrabranched polysiloxane having the following structure

(In the formula, R is a hydrogen or alkyl group; n is an integer of 2 to 200; all four branched chains have the same structure.)
The method according to claim 16 . An adhesive containing a crosslinked polymer according to any one of claims 1 to 9. The adhesive according to claim 27 , which is a hot melt type adhesive. A material having a crosslinked polymer on the surface according to any one of claims 1 to 9. A method for adhering materials, which comprises adhering and detaching two or more materials using the method according to any one of claims 16 to 26 . A resin material for a 3D printer containing the crosslinked polymer according to any one of claims 1 to 9.