JP2021088620A - Crosslinked structure, method for manufacturing crosslinked structure, and surface-treated base material - Google Patents

Abstract

To provide a crosslinked structure which has a small efficient of friction on a surface, exhibits excellent low friction, is excellent in mechanical strength and durability, is suitable as a material for configuring a sliding surface of a sliding member, and can be easily manufactured.SOLUTION: The crosslinked structure is a crosslinked product of a polysiloxane graft polymer and a crosslinking agent. The polysiloxane graft polymer has a structural unit (a) derived from polydimethylsiloxane having a (meth)acryloyl group on one terminal, a structural unit (b) derived from a (meth)acrylate-based monomer having a crosslinkable functional group, and a structural unit (c) derived from a radical-polymerizable vinyl-based monomer. A mass ratio of the structural unit (a), the structural unit (b) and the structural unit (c) in the polysiloxane graft polymer is (a):(b):(c)=50-90:5-50:0-45.SELECTED DRAWING: None

Description

The present invention relates to a flexible and low friction crosslinked structure, a method for producing the same, and a surface-treated substrate using the same.

As a method of providing a polymer layer on the surface of a base material such as an article to modify the surface, a polymer having an adsorptive group or a reactive group at the end thereof is allowed to act on the surface of the base material, and the surface of the base material is physically or A method of forming a chemically grafted polymer layer is known. Further, a method of polymerizing a monomer from a polymerizable group imparted to the surface of a base material to form a polymer layer grafted from the surface of the base material is also known.

In recent years, so-called concentrated polymer brushes in which a polymer is densely grafted onto a substrate using a living radical polymerization technique developed in the 1990s have been studied. A concentrated polymer brush is a polymer chain grafted onto a substrate at a high density of 1 to 4 nm intervals. It has been proposed that the surface of the base material is modified by such a concentrated polymer brush to impart properties such as low friction, protein adsorption suppression, size exclusion property, hydrophilicity, and water repellency to the base material (patented). Documents 1 and 2 and Non-Patent Documents 1 to 3).

Japanese Unexamined Patent Publication No. 2008-133434 JP-A-2010-261001

Adv. polym. Sci. , 2006, 197, 1-45 J. AM. CHEM. SOC. , 2005, 127, 15843-15847 Polym. Chem. , 2012, 3, 148-153

Concentrated polymer brushes exhibit low friction in tribological areas such as lubrication, friction and wear. In the concentrated polymer brush, for example, a substrate having a polymerization initiating group capable of living radical polymerization added to its surface is immersed in a monomer polymerization solution having no impurities such as oxygen and water, and by living radical polymerization such as atomic transfer radical polymerization. It can be produced by forming a brush-like polymer. Since it is necessary to wash and dry the base material taken out from the polymerization solution after the completion of the polymerization, there is a problem that the manufacturing process as a whole is long and complicated. Furthermore, the surplus polymerization solution had to be discarded, and there were problems in terms of environment and resources.

In addition, the polymer layer constituting the concentrated polymer brush may be detached from the surface of the base material due to the lubricating oil or solvent used during friction. The concentrated polymer brush is usually formed by forming a polymerization initiation base layer, which is a monomolecular film layer, and then polymerizing a monomer. However, since the binding force of the monolayer is not so strong and the adhesion is weak, it is considered that the polymer layer is easily detached at the time of friction.

The present invention has been made in view of the problems of the prior art, and the problems thereof are that the friction coefficient of the surface is small, excellent low friction property is exhibited, and mechanical strength and mechanical strength are exhibited. An object of the present invention is to provide an easily manufacturable crosslinked structure which is excellent in durability and is suitable as a material or the like for forming a sliding surface of a sliding member. Another object of the present invention is to provide a method for producing the crosslinked structure and a surface-treated base material using the crosslinked structure.

That is, according to the present invention, the following crosslinked structure is provided.
[1] At least one selected from the group consisting of a polysiloxane graft polymer having a number average molecular weight of 10,000 to 100,000, an isocyanate-based cross-linking agent, a polyglycidyl-based cross-linking agent, a polycarboxylic acid-based compound, a polyol, and a polyamine. The cross-linked product of the above, and the polysiloxane graft polymer is a structural unit (a) derived from a polydimethylsiloxane having a molecular weight of 1,000 to 20,000 having a (meth) acryloyl group at one end. , A structural unit (b) derived from a (meth) acrylate-based monomer having at least one crosslinkable functional group selected from the group consisting of a hydroxyl group, a carboxy group, an isocyanate group, a blocked isocyanate group, and a glycidyl group, and a radical. It has a structural unit (c) derived from a polymerizable vinyl-based monomer, and has a mass ratio of the structural unit (a), the structural unit (b), and the structural unit (c) in the polysiloxane graft polymer. However, the crosslinked structure in which (a): (b): (c) = 50 to 90: 5 to 50: 0 to 45.
[2] It is swollen with at least one oil selected from the group consisting of hydrocarbon-based lubricating oil, polyester polyol-based lubricating oil, polyolefin-based lubricating oil, silicone-based lubricating oil, and alkyl halide-based lubricating oil, and is swollen. The crosslinked structure according to the above [1], which is a gel swelling body that has linearly expanded 1.5 times or more as compared with the previous one.
[3] The polydimethylsiloxane contains a first polydimethylsiloxane and a second polydimethylsiloxane having different molecular weights from each other, and the first polydimethylsiloxane has a molecular weight of 1,000 to 5,000. The second polydimethylsiloxane has a molecular weight of 5,000 to 20,000, and the structural unit (a) is a structural unit (a-1) derived from the first polydimethylsiloxane, and the second. The crosslinked structure according to the above [1] or [2], which comprises a structural unit (a-2) derived from the polydimethylsiloxane of.
[4] The crosslinked structure according to any one of [1] to [3], wherein the polysiloxane graft polymer has a molecular weight distribution (weight average molecular weight / number average molecular weight) of 1.5 or less.
[5] The crosslinked structure according to any one of [1] to [4] above, which is a film-like molded product having a thickness of 100 nm or more.

Further, according to the present invention, a method for producing a crosslinked structure shown below is provided.
[6] The method for producing a crosslinked structure according to any one of [1] to [5], which comprises the polydimethylsiloxane, the (meth) acrylate-based monomer, and the radically polymerizable vinyl-based monomer. A method for producing a crosslinked structure, comprising a polymerization step of polymerizing a monomer component to obtain the polysiloxane graft polymer, and a crosslinking step of crosslinking the obtained polysiloxane graft polymer with the crosslinking agent.
[7] The method for producing a crosslinked structure according to the above [6], wherein the monomer component is polymerized by a living radical polymerization method using an organic compound having an iodine atom as a polymerization initiator to obtain the polysiloxane graft polymer.

Further, according to the present invention, the following surface-treated base materials are provided.
[8] A crosslinked structure according to any one of [1] to [5], comprising a base material and a polymer layer arranged on the surface of at least a part of the base material. A surface treatment substrate.

According to the present invention, the friction coefficient of the surface is small, the friction coefficient is excellent, and the mechanical strength and durability are excellent, which is suitable as a material for forming a sliding surface of a sliding member. It is possible to provide a crosslinked structure that can be easily manufactured. Further, according to the present invention, it is possible to provide a method for producing the crosslinked structure and a surface-treated base material using the crosslinked structure.

The crosslinked structure of the present invention can be easily formed by applying a mixture of a specific polysiloxane graft polymer and a coating liquid containing a crosslinking agent to the surface of a base material and then subjecting the crosslinks to a crosslinking reaction. That is, since complicated steps and strict polymerization condition control when manufacturing a concentrated polymer brush are not required, it is advantageous in terms of cost reduction and resource saving. Further, a gel swelling body can be obtained by swelling with oil (lubricating oil) as needed. The gel swelling body thus formed exhibits low frictional properties equal to or higher than that of the concentrated polymer brush, and is therefore suitable as a material for forming the sliding surface of the sliding member.

Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to the following embodiments. Unless otherwise specified, the various physical property values in the present specification are values at room temperature (25 ° C.).

<Cross-linked structure>
The crosslinked structure of the present invention is a crosslinked product of a polysiloxane graft polymer having a number average molecular weight of 10,000 to 100,000 and a specific crosslinking agent. The polysiloxane graft polymer is derived from a structural unit (a) derived from polydimethylsiloxane, a structural unit (b) derived from a (meth) acrylate-based monomer having a crosslinkable functional group, and a radically polymerizable vinyl-based monomer. It has a structural unit (c). The polydimethylsiloxane constituting the structural unit (a) is a silicone macromonomer having a molecular weight of 1,000 to 20,000 and having a (meth) acryloyl group at one end thereof. The (meth) acrylate-based monomer constituting the structural unit (b) has at least one crosslinkable functional group selected from the group consisting of a hydroxyl group, a carboxy group, an isocyanate group, a blocked isocyanate group, and a glycidyl group. Hereinafter, the details of the crosslinked structure of the present invention will be described.

(Polysiloxane graft polymer)
[Structural unit (a)]
The polysiloxane graft polymer has a structural unit (a) derived from polydimethylsiloxane having a (meth) acryloyl group at one end thereof (hereinafter, also simply referred to as "polydimethylsiloxane"). This polydimethylsiloxane is a so-called silicone macromonomer having a (meth) acryloyl group, which is a polymerizable group, at one end thereof. The connecting portion between the (meth) acryloyl group and the polydimethylsiloxane and the terminal other than the (meth) acryloyl group may be any organic group, preferably a hydrocarbon. Silicone macromonomer is a high-molecular-weight macromonomer, has poor polymerization reactivity, and is difficult to gel during polymerization. Therefore, (meth) acryloyl groups may be bonded to both ends or a part of the side chain. It may have two or more (meth) acryloyl groups.

Examples of the silicone macromonomer (polydimethylsiloxane) include (meth) acryloyloxypropyl polydimethylsiloxane methyl and (meth) acryloyloxypropyl polydimethylsiloxane butyl. As these silicone macromonomers, commercially available products sold by Shin-Etsu Chemical Co., Ltd., Toagosei Co., Ltd., JNC Corporation, etc. may be used, or those prepared by anionic polymerization may be used.

The molecular weight of the silicone macromonomer is 1,000 to 20,000, preferably 2,000 to 15,000, and even more preferably 2,200 to 13,000. The molecular weight of the silicone macromonomer (polydimethylsiloxane) is a value obtained by converting from the number of protons of dimethylsiloxane per mol of the terminal (meth) cryloyl group measured by a nuclear magnetic resonance apparatus (NMR). If the molecular weight of the silicone macromonomer is less than 1,000, the low friction property becomes insufficient, and when swelling with oil (lubricating oil) is attempted, the swelling property may be insufficient. On the other hand, if the molecular weight of the silicone macromonomer is more than 20,000, the reactivity may decrease and non-polymerizing components may remain, or the viscosity may become too high and gelation may occur.

The polydimethylsiloxane preferably contains a first polydimethylsiloxane and a second polydimethylsiloxane having different molecular weights from each other. The molecular weight of the first polydimethylsiloxane is 1,000 to 5,000. The molecular weight of the second polydimethylsiloxane is 5,000 to 20,000. Then, the structural unit (a) in the polysiloxane graft polymer is a structural unit (a-1) derived from the first polydimethylsiloxane and a structural unit (a-2) derived from the second polydimethylsiloxane. , Are preferably included. Since the second polydimethylsiloxane has a relatively high molecular weight, if all of the structural unit (a) is to be composed of the second polydimethylsiloxane, the second polydimethylsiloxane that could not be completely reacted remains. Sometimes. On the other hand, since the first polydimethylsiloxane has a relatively low molecular weight, if all of the structural unit (a) is to be composed of the first polydimethylsiloxane, the frictional property of the obtained crosslinked structure is sufficiently lowered. It may not be possible. Therefore, by coexisting the structural unit (a-1) and the structural unit (a-2) in the structural unit (a), a higher molecular weight silicone macromonomer is reasonably introduced into the polysiloxane graft polymer. be able to. Further, the unreacted monomer is unlikely to remain, and the polysiloxane graft polymer can be obtained at a higher polymerization rate. The content ratio of the structural unit (a-2) in the structural unit (a) is preferably 10 to 50% by mass, and more preferably 20 to 40% by mass.

[Structural unit (b)]
The polysiloxane graft polymer has a structural unit (b) derived from a (meth) acrylate-based monomer having a crosslinkable functional group (hereinafter, also simply referred to as “(meth) acrylate-based monomer”). The crosslinkable functional group is at least one selected from the group consisting of a hydroxyl group, a carboxy group, an isocyanate group, a blocked isociate group, and a glycidyl group. When this crosslinkable functional group reacts with the crosslinking agent, a crosslinked structure having a three-dimensional network structure is formed.

Examples of the (meth) acrylate-based monomer having a hydroxyl group include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and poly (n = 2 or more) alkylene (C2-). C4) Glycol mono (meth) acrylate, (meth) acryloyloxy 1-chloro-2-hydroxypropane, metaacryloyloxy 1,2-dihydroxypropane and the like can be mentioned.

Examples of the (meth) acrylate-based monomer having a carboxy group include (meth) acrylic acid, (meth) acryloyloxyethyl phthalic acid, (meth) acryloyloxyethyl maleic acid, and (meth) acryloyloxyethyl succinic acid. it can

Examples of the (meth) acrylate-based monomer having an isocyanate group include (meth) acryloyloxyethyl isocyanate, (meth) acryloyloxyethoxyethyl isocyanate, and 1,5- (bis (meth) acryloyloxymethyl) ethyl isocyanate. it can.

Examples of the (meth) acrylate-based monomer having a blocked isocyanate group include 2-[(3,5-dimethylpyrazolyl) carboxyamino] ethyl (meth) acrylate and 2-([1'-methylpropyrineamino] carboxyamino). Ethyl (meth) acrylate and the like can be mentioned.

Examples of the (meth) acrylate-based monomer having a glycidyl group include glycidyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate, 2- [2- (2-oxylanylmethoxy) ethoxy] ethyl methacrylate and the like. Can be mentioned.

[Structural unit (c)]
The polysiloxane graft polymer may be substantially composed of only the structural unit (a) and the structural unit (b), and other structural units other than the structural unit (a) and the structural unit (b) (constituent unit (constituent unit (b)). c)) may be further provided. The structural unit (c) is a structural unit derived from a radically polymerizable vinyl-based monomer that can be copolymerized with polydimethylsiloxane and a (meth) acrylate-based monomer.

Examples of such radically polymerizable monomers include aromatics such as styrene, vinyltoluene, vinylnaphthalene, vinyl benzoic acid, and lower alcohol esters of vinyl benzoic acid, vinyl carbazole, styrene sulfonic acid, and lower alcohol esters of styrene sulfonic acid. Heterocyclic vinyl monomer; aliphatic, alicyclic, or aromatic carboxylic acid vinyl ester monomers such as vinyl acetate, vinyl propionate, vinyl cyclohexanecarboxylate, vinyl benzoate; methyl, ethyl, propyl, butyl, amyl, hexyl, 2-Ethylhexyl, octyl, nonyl, dodecyl, hexadecyl, octadecyl, isostearyl, behenyl, cyclohexyl, trimethylcyclohexyl, t-butylcyclohexyl, dicyclopentanyl, dicyclopentenyl, isobornyl, benzyl, methoxyethyl, butoxyethyl, phenoxyethyl , Monofunctional (meth) actacrylates with substituents such as nonylphenoxyethyl, dicyclopentenyloxyethyl, dimethylaminoethyl, diethylaminoethyl; (meth) acrylamide, dimethyl (meth) acrylamide, (meth) acryloylmorpholine, Amido-based monomers such as N-methylol (meth) acrylamide; (meth) acrylonitrile; N-vinylpyrrolidone; lower alcohol esters of maleic anhydride, maleic acid, and maleic acid, N-phenylmaleimide, N-cyclohexylmaleimide, itacone anhydride Examples thereof include acid, itaconic acid, and vinyl dibasic acid-based monomers such as lower alcohol esters of itaconic acid.

The mass ratio of the structural unit (a), the structural unit (b), and the structural unit (c) in the polysiloxane graft polymer is (a) :( b) :( c) = 50 to 90: 5 to 50: 0. ~ 45. If the content of the structural unit (b) in the polysiloxane graft polymer is less than 5% by mass, the concentration of the crosslinkable functional group is too low, so that the crosslink density is lowered and the strength of the obtained crosslinked structure is increased. Run short. On the other hand, if the content of the structural unit (b) in the polysiloxane graft polymer is more than 50% by mass, the crosslink density becomes too high, and even if oil (lubricating oil) is added to the obtained crosslinked structure. The degree of swelling may be low or may not swell. The content of the structural unit (b) in the polysiloxane graft polymer is preferably 7 to 30% by mass, more preferably 10 to 20% by mass, based on the entire polysiloxane graft polymer.

[Polysiloxane Graft Polymer]
The number average molecular weight of the polysiloxane graft polymer is 10,000 to 100,000, preferably 20,000 to 50,000. The number average molecular weight of the polysiloxane graft polymer is a polystyrene-equivalent value measured by gel permeation chromatography (GPC). If the number average molecular weight of the polysiloxane graft polymer is less than 10,000, the mechanical strength of the crosslinked structure is insufficient. On the other hand, when the number average molecular weight of the polysiloxane graft polymer is more than 100,000, the viscosity of the solution (coating liquid) of the polysiloxane graft polymer becomes too high and the coatability deteriorates. If an attempt is made to reduce the viscosity of the coating liquid, the amount of solid content becomes insufficient, and it becomes difficult to form a film (polymer layer) having a sufficient thickness.

The molecular weight distribution (PDI = weight average molecular weight (Mw) / number average molecular weight (Mn)) of the polysiloxane graft polymer is preferably 1.5 or less, and more preferably 1.3 or less. That is, the molecular weight of the polysiloxane graft polymer is preferably less variable and more uniform. By using a polysiloxane graft polymer having a more uniform molecular weight, the three-dimensional network structure of the crosslinked structure to be formed tends to be uniform, and the degree of swelling can be increased.

The polysiloxane graft polymer may be an ordinary random copolymer as long as the polysiloxane is grafted. Further, the silicone macromonomer may be a block copolymer in which the (meth) acrylate-based monomer and the radically polymerizable vinyl monomer are concentrated in the other polymer block while the silicone macromonomer is concentrated in one polymer block; the silicone macromonomer may be a block copolymer. It may be a polymer having a gradually increasing gradient structure. Of these, block copolymers in which the silicone macromonomer is concentrated in one polymer block and the (meth) acrylate-based monomer and the radically polymerizable vinyl monomer are concentrated in the other polymer block are preferable.

(Crosslinking agent)
The crosslinked structure of the present invention is a crosslinked product of the above polysiloxane graft polymer and a specific crosslinking agent. Specifically, the crosslinkable functional group in the polysiloxane graft polymer and the crosslinking agent undergo a crosslink reaction between multiple molecules to form a three-dimensional network structure, and a crosslinked structure is formed. The cross-linking agent is at least one selected from the group consisting of isocyanate-based cross-linking agents, polyglycidyl-based cross-linking agents, polycarboxylic acid-based compounds, polyols, and polyamines.

As the isocyanate-based cross-linking agent, a compound having 2 or more isocyanate groups, preferably 3 or more isocyanate groups in the molecule is used. Examples of the compound having two isocyanate groups include toluene diisocyanate, diphenylmethane diisocyanate, naphthalenediocyanate, xylylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, trimethylhexamethylene diisocyanate, lysine diisocyanate, bis (isocyanatomethyl) cyclohexane, and dicyclohexylmethane diisocyanate. Examples thereof include isopropyridene biscyclohexyl isocyanate and diphenyl ether diisocyanate. Examples of the compound having three isocyanate groups include lysine triisocyanate, tris (isocyanatophenyl) methane, tris (isocyanatophenyl) thiophosphate and the like. Examples of the polyfunctional isocyanate having 4 or more isocyanate groups include a biuret form, a uretdione form, an isocyanurate form, and an adduct form of the above compounds.

Further, a blocked isocyanate in which an isocyanate group is blocked by reacting the above-mentioned polyfunctional isocyanate with an active hydrogen compound such as methanol, ethanol, propanol, butanolphenol, benzyl alcohol, methylamine, ethylamine, dibutylamine, and epsilon caprolactone. Compounds and the like can also be used.

A polyglycidyl-based cross-linking agent is a compound having two or more glycidyl groups, preferably three or more glycidyl groups in the molecule. Compounds having two glycidyl groups include 1,4-butanediol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, diethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, and propylene glycol. Diglycidyl ether, polypropylene glycol diglycidyl ether, biphenol diglycidyl ether, bisphenol A diglycidyl ether, hydrogenated bisphenol A diglycidyl ether, resorcinol diglycidyl ether, cyclohexanedimethanol diglycidyl ether, condensation of bisphenol A and epichlorohydrin Products, condensation products of bisphenol F and epichlorohydrin, condensation products of bisphenol S and epichlorohydrin, diglycidyl 1,2-cyclohexanedicarboxylate, diglycidyl phthalate, polydimethylsiloxane dipropyldiglycidyl ether, etc. Can be mentioned.

Examples of the compound having 3 or more glycidyl groups include glycerin triglycidyl ether, trimethylpropan triglycidyl ether, pentaerythritol tetraglycidyl ether, poly (n> 2) glycerol polyglycidyl ether, sorbitol polyglycidyl ether, and phenol novolac polyglycidyl ether. , Cresol novolac polyglycidyl ether, triglycidyl isocyanurate, epoxidized soybean oil, epoxidized flaxseed oil, polydimethylsiloxane alkyl polyglycidyl ether, N, N, N', N'-tetraglycidyl-m-xylylene diamine, etc. Can be mentioned.

A polycarboxylic acid-based compound is a compound having two or more carboxylic acid groups (carboxy groups) in the molecule. Examples of polycarboxylic acid compounds include oxalic acid, succinic acid, adipic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, tridecanedioic acid, tetradecanedioic acid, pentadecanedioic acid, hexadecanedioic acid, and heptadecanedioic acid. , Octadecandioic acid, methylsuccinic acid, octylsuccinic acid, dodecylsuccinic acid, octadecylsuccinic acid, methylglutaric acid, fumaric acid, maleic acid, itaconic acid, citraconic acid, cyclohexanedicarboxylic acid, cyclohexanedimethyldicarboxylic acid, 1, 2, 3 , 6-Hexahydrophthalic acid, phthalic acid, isophthalic acid, naphthalenedicarboxylic acid, butentricarboxylic acid, cyclohexanetricarboxylic acid, 3-butene-1,2,3-tricarboxylic acid, cyclohexanetricarboxylic acid, pentantricarboxylic acid, tris (2) -Carboxyethyl) -1,3,5-triazine, tris (3-carboxypropyl) -1,3,5-triazine, trisisosianurate (2-carboxyethyl), trisisocyanurate (3-carboxypropyl), tri Merit acid, hemimeritic acid, benzene-1,3,5-tricarboxylic acid, butanetetracarboxylic acid, cyclohexanetetracarboxylic acid, pyromellitic acid, benzophenonnetetracarboxylic acid, biphenyltetracarboxylic acid, diphenylsulfonetetracarboxylic acid, oxydiphthal Examples thereof include acids, naphthalenetetracarboxylic acids, fluorene-9,9-bisphthalic acids, cyclohexanehexacarboxylic acids and the like. The carboxy group of these polycarboxylic acid compounds may be blocked with vinyl ether, benzyl alcohol, t-butyl alcohol and the like. Moreover, the polycarboxylic acid compound may be an acid anhydride.

A polyol is a compound having two or more hydroxyl groups in the molecule. Examples of the polyol include ethylene glycol, propylene glycol, butanediol, hexamethylenediol, neopentyl glycol, cyclohexanediol, cyclohexanedimethanol, xylylene glycol, poly (n ≧ 2) ethylene glycol, and poly (n ≧ 2) propylene glycol. Diol compounds such as poly (n ≧ 2) ethylene propylene glycol, polytetramethylene glycol, polydimethylsiloxane propyldiol, polyhexamethylene carbonate; other glycerin, polyglycerin, dimethylolpropane, dimethylolbutane, pentaerythritol, di Pentaerythritol, sorbitol, EO or PO adducts thereof, esterified products of dicarboxylic acid and diol compound, polyester which is a ring-opening polymer of cyclic ester starting from diol, both ends obtained by reacting diisocyanate with diol. Examples thereof include hydroxyl group polyurethane, polyvinyl polyol having a vinyl monomer having a hydroxyl group as a copolymerization component, and a reaction product of bisphenol A and diamine.

A polyamine is a compound having two or more amino groups in the molecule. Examples of polyamines include hydrazine, ethylenediamine, 1,3-propanediamine, 1,4-butanediamine, hexamethylenediamine, 4,4'-diphenylmethanediamine, 1,3- or 1,4-xylylenediamine, and isophoronediamine). , 1,3-bis (aminomethyl) cyclohexane, 1,4-cyclohexanediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, polyethylenediamine and the like.

The cross-linking agent can be appropriately selected and used depending on the type of cross-linking functional group in the polysiloxane graft polymer. For example, when the crosslinkable functional group is a hydroxyl group, it is preferable to use an isocyanate-based crosslinker or a polycarboxylic acid compound. When the crosslinkable functional group is a carboxy group, it is preferable to use an isocyanate-based crosslinker, a polyol, or a polyglycidyl-based crosslinker. When the crosslinkable functional group is an isocyanate or a blocked isocyanate group, it is preferable to use a polyglycidyl-based cross-linking agent, a polycarboxylic acid-based compound, a polyol, or a polyamine. When the crosslinkable functional group is a glycidyl group, it is preferable to use an isocyanate-based cross-linking agent, a polycarboxylic acid-based compound, or a polyamine.

A number of moles M _P crosslinkable functional groups in the polysiloxane graft polymer, the number of moles M _C reactive groups in the crosslinking agent used for crosslinking the polysiloxane graft polymer, the relationship between the M _P ≧ M _C It is preferable to satisfy. By reacting the polysiloxane graft polymer with the cross-linking agent so as to satisfy the above relationship, the cross-linking performance can be further enhanced. It is not necessary that all the crosslinkable functional groups in the polysiloxane graft polymer are reacted and consumed, and it is sufficient that the amount of the crosslinkable functional groups in which the crosslinked structure is formed reacts.

(oil)
The crosslinked structure is at least one oil (lubricating oil) selected from the group consisting of hydrocarbon-based lubricating oils, polyester polyol-based lubricating oils, polyolefin-based lubricating oils, silicone-based lubricating oils, and alkyl halide-based lubricating oils. It is preferably a swollen gel swollen body. By forming a gel swelling body swollen with oil, it is possible to obtain a surface treatment film having further improved characteristics such as low friction. The gel swelling body is preferably linearly expanded 1.5 times or more as compared with that before swelling.

The oil (lubricating oil) may be a mineral-based lubricating oil base oil or a synthetic lubricating oil base oil. Hydrocarbon-based lubricating oils include alkylbenzene, alkylnaphthalene, di (n-octyl) cyclopentane, di (n-decyl) cyclopentane, di (n-dodecyl) cyclopentane, tris- (n-octyl) cyclopentane, Examples thereof include tris (n-decyl) cyclopentane, tris (n-dodecyl) cyclopentane, and tris (2-octyldodecyl) cyclopentane.

Examples of polyester polyol-based lubricating oils include butylstearate, octyllaurate, dimethylolpropane, di-2-ethylhexyl adipate, diisodecyl adipate, ditridecyl adipate, di-2-ethylhexyl sevacate, and trimellitic acid trioctyl ester. Trimethylolpropane caprilate, trimethylolpropane trihexanoate, trimethylolpropane trilaurate, trimethylolpropane trioleate, trimethylolpropane triisostearate, pentaerythritol-2-ethylhexanoate, pentaerythritol tetraoleate , Tricredyl phosphate and the like.

Examples of the polyolefin-based lubricating oil include ethylene-propylene copolymers, polybutenes, 1-octene oligomers, 1-decene oligomers, hydrogenated products thereof and the like. Examples of the silicone-based lubricating oil include dimethylsiloxane, phenylmethylsiloxane, and cyclic dimethylsilicone oil. Examples of the alkyl halide-based lubricating oil include non-fluorocarbon type refrigerants such as chlorofluorocarbon and hydrochlorofluorocarbon.

By swelling the crosslinked structure with oil, it can be made into a gel swelling body (gel swelling film).
As a method of swelling the crosslinked structure, for example, a method of immersing the crosslinked structure arranged on the surface of the base material in lubricating oil and heating it as necessary; the crosslinked structure is arranged on the surface thereof. After assembling a molded body, an apparatus, or the like using a base material, there is a method of injecting oil into a crosslinked structure (surface of the base material). Further, a crosslinked structure (gel swollen body) in a state of being swollen with oil is obtained by applying a solution obtained by previously dissolving a polysiloxane graft polymer and a crosslinking agent in oil on the surface of a base material and then heating and crosslinking. ) Can be formed. The excess oil can be removed by shaking off with a spin coater or by centrifuging.

The gel swelling body is preferably linearly expanded 1.5 times or more as compared with that before swelling, and more preferably 2.0 times or more. The gel swelling body in which the crosslinked structure is swelled with oil exhibits low friction due to grafting. It is considered that this is because the dimethylsiloxane chain becomes a free polymer chain capable of free movement by swelling. Further, since oil can be supplied to the surface and oil can be absorbed, it has a function as a liquid reservoir of oil. If the linear expansion is less than 1.5 times, the expansion may be insufficient, and the characteristics such as low friction may be slightly insufficient.

<Manufacturing method of crosslinked structure>
The crosslinked structure of the present invention can be produced, for example, according to the method shown below. That is, the method for producing a crosslinked structure of the present invention includes a polymerization step of polymerizing a monomer component containing a polydimethylsiloxane, a (meth) acrylate-based monomer, and a radically polymerizable vinyl-based monomer to obtain a polysiloxane graft polymer. It has a cross-linking step of cross-linking the obtained polysiloxane graft polymer with a cross-linking agent.

(Polymerization process)
In the polymerization step, a monomer component containing a polydimethylsiloxane, a (meth) acrylate-based monomer, and a radically polymerizable vinyl-based monomer is polymerized by, for example, radical polymerization or living radical polymerization. In radical polymerization, for example, an azo compound such as azobisisobutyronitrile or a peroxide such as benzoyl peroxide is used as a radical generator in an organic solvent, and a thiol compound, a halide or the like is chained as necessary. It can be used as a transfer agent and heated to carry out. As the living radical polymerization, (i) an atomic transfer radical polymerization method using an oxidation-reduction of a metal complex using a halogenated organic compound as an initiating group compound and a metal complex such as copper or ruthenium; (ii) a nitroxide compound. Thermal living radical polymerization method to be used; (iii) Reversible addition-disruption type chain transfer polymerization using dithioester, dithiocarbamate, zantate, etc .; (iv) Method using organic tellurium; (v) Using an iodine compound as an initiator Iodine transfer polymerization; (vi) Reversible mobile catalyst polymerization or reversible catalyst-mediated polymerization using a halogenated organic compound as an initiator and an organic compound capable of extracting iodine radicals as a catalyst; and the like can be mentioned. Further, in order to prevent gelation due to rapid polymerization of the silicone macromonomer, a polysiloxane graft polymer can also be obtained by a radical polymerization method or a living radical polymerization method in which a chain transfer agent is added.

Among them, it is preferable to obtain a polysiloxane graft polymer by polymerizing the monomer components by a living radical polymerization method using an organic compound having an iodine atom as a polymerization initiator. This living radical polymerization method is described in detail in, for example, Japanese Patent No. 4543178, Japanese Patent No. 5850599, Japanese Patent No. 5697026, Japanese Patent No. 5881292, Japanese Patent No. 5610402, Japanese Patent No. 5995884, and the like. ing.
In this living radical polymerization method, a polysiloxane graft polymer having a more uniform molecular weight and a narrower molecular weight distribution (for example, PDI ≤ 1.5) is obtained by using it as an organic compound (iodine compound) polymerization initiator having an iodine atom. It is preferable because it can be obtained. Further, since a polysiloxane graft polymer can be obtained by using a commercially available inexpensive material without requiring a special material, it is cost-effective and environmentally friendly.

As the organic solvent for polymerization, it is preferable to use an organic solvent that does not easily react with the crosslinkable functional group in the polysiloxane graft polymer. For example, when the obtained polysiloxane graft polymer has an isocyanate group, it is not preferable to use an organic solvent containing a hydroxyl group. Examples of the organic solvent for polymerization include hydrocarbon solvents such as hexane, toluene and xylene; alcohol solvents such as methanol, ethanol, isopropanol, butanol and dodecanol; and ketone solvents such as acetone, methyl ethyl ketone, diethyl ketone and isobutyl methyl ketone. Ester solvents such as ethyl acetate, butyl acetate, amyl acetate, dimethyl succinate, dimethyl adipate, methyl lactate, dimethyl lactate; ether solvents such as dipropyl ether, tetrahydrofuran, dioxane; dimethyl carbonate, ethylene carbonate, propylene carbonate Such as carbonate solvents; N, N-dimethylformamide, N, N-dimethylacetamide, pyrrolidone, N-methylpyrrolidone, 3-methoxy-N, N-dimethylpropanamide, 3-butoxy-N, N-dimethylpropanamide. Amido-based solvents such as: Tetramethylurea, Urea-based solvents such as dimethylimidazolidinone; Sulfoxide solvents such as dimethylsulfoxide; Ethylene glycol, propylene glycol, diethylene glycol, ethylene glycol methyl ether, ethylene glycol butyl ether, diethylene glycol methyl ether, diethylene glycol mono Glycol monoether solvents such as butyl ether, triethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether; ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, dipropylene Glycoldiether-based solvent such as glycol dimethyl ether; glycol ether monoether ester solvent such as ethylene glycol monomethyl ether acetate, diethylene glycol monomethyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monobutyl ether acetate; polydimethylsiloxane, polyphenylmethyl siloxane And the like; silicone-based solvents such as methylene chloride, tetrafluoroethane, polyfluoroalkane and the like; and the like. Of these, it is preferable to use a low to medium polar solvent capable of dissolving the siloxane macromonomer, and more preferably a hydrocarbon solvent, a ketone solvent, an ether solvent, an ester solvent, a glycol ester solvent, and a silicone solvent. ..

(Crosslinking process)
In the cross-linking step, the polysiloxane graft polymer obtained in the polymerization step is reacted with a cross-linking agent to cross-link. Thereby, the desired crosslinked structure can be obtained. A one-component coating solution can be prepared by dissolving the polysiloxane graft polymer and the cross-linking agent in an appropriate organic solvent. Further, a two-component coating solution composed of a first solution in which a polysiloxane graft polymer is dissolved in an organic solvent and a second solution in which a cross-linking agent is dissolved in an organic solvent may be prepared. In any case, if the coating liquid is applied to the surface of a suitable base material, heated as necessary, the solvent is volatilized, and the polysiloxane graft polymer and the cross-linking agent are cross-linked, the cross-linked structure is formed. Can be formed.

The temperature (heating temperature) at the time of the cross-linking reaction is the reactivity between the cross-linking functional group in the polysiloxane graft polymer and the reactive group in the cross-linking agent, and the ease of deprotection of the blocked cross-linking functional group. It is set appropriately in consideration of such factors. Specifically, heating to 100 ° C. or higher is preferable because the cross-linking reaction can be substantially advanced. The concentrations of the polysiloxane graft polymer and the cross-linking agent in the coating liquid may be appropriately set in consideration of the coatability of the coating liquid, the thickness of the cross-linked structure (film-like structure) to be formed, and the like.

Additives for improving coatability, catalysts for promoting cross-linking reaction, and the like can be added to the coating liquid. Further, conventionally known additives may be added to the coating liquid. Additives include, for example, wetting agents, anti-dripping agents, leveling agents, thixotropic agents, defoaming agents, viscosity modifiers, anti-drying agents, curing catalysts, photoacid generators, photobase generators, antioxidants. , Ultraviolet absorbers, light stabilizers, surfactants, dyes, pigments, other polymer components and the like. Further, a filler for improving the strength of the crosslinked structure such as silica, carbon fiber, cellulose fiber, cellulose nanofiber, and cellulose nanowhisker can also be added.

<Surface treatment base material>
By arranging the above-mentioned crosslinked structure on the surface of the base material, the surface-treated base material of the present invention can be obtained. That is, the surface-treated base material of the present invention includes a base material and a polymer layer arranged on the surface of at least a part of the base material, and this polymer layer is the above-mentioned crosslinked structure.

As for the base material, the material, shape, size and the like are not particularly limited, and a conventionally known base material can be used. Specific examples of the material of the base material include metals, plastics, woods, minerals, and organic substances. Specific examples of the shape of the base material include fine particles, particles, lumps, films, various molded products, fibers, sheets and the like.

In order to arrange the polymer layer, which is a crosslinked structure, on the surface of the base material, as described above, a coating liquid containing a polysiloxane graft polymer and a crosslinking agent is applied to the base material, and then the polysiloxane graft polymer is applied according to a conventional method. May be crosslinked to form a crosslinked structure (polymer layer). Methods for applying the coating liquid to the substrate include spin coating, dip coating, inkjet, edge casting, spray coating, flow coating, roll coating, doctor blade coating, bar coating, slit coating, clavier coating, screen printing, and the like. There is.

The polymer layer arranged on the surface of the base material is a film-like molded product of a crosslinked structure having a predetermined thickness. The thickness of this film-shaped molded product (polymer layer) is preferably 100 nm or more, more preferably 200 nm or more, and further preferably 500 nm or more, from the viewpoint of exhibiting appropriate low frictional properties. Especially preferable.

The crosslinked structure of the present invention and the surface (polymer layer) of the surface-treated substrate using the crosslinked structure are excellent in low friction because the grafted polysiloxane exhibits slipperiness. Further, since it has a crosslinked structure, it is excellent in mechanical strength and also has good scratch resistance and the like. Furthermore, since it is a soft gel substance, it has the property of being flexible. Therefore, the crosslinked structure of the present invention and the surface-treated base material using the same can be used as a portion where energy loss is likely to occur due to friction of, for example, mechanical parts, moving parts of equipment, rotating parts of equipment, driving parts of equipment, and the like. Energy loss can be reduced by using the constituent members.

Hereinafter, the present invention will be specifically described based on examples, but the present invention is not limited to these examples. In addition, "part" and "%" in Examples and Comparative Examples are based on mass unless otherwise specified.

<Manufacturing of polysiloxane graft polymer>
(Synthesis Example 1)
In a separable flask equipped with a stirrer, a cooling tube, a nitrogen introduction device, and a thermometer, 300 parts of dipropylene glycol dimethyl ether (DPGDM), methacryloyloxypropyl polydimethylsiloxane butyl (silicone macromonomer (1), molecular weight: 4, 600) 100 parts, 20 parts of methacrylic acid (MAA), 60 parts of 2-ethylhexyl methacrylate (2EHMA), and 1 part of bis (4-t-butylcyclohexyl) peroxycarbonate (TCP) were charged. Polymerization at 45 ° C. for 8 hours gave a solution of the polysiloxane graft polymer SG-1.

The molecular weight of the silicone macromonomer (1) is a value obtained by converting from the number of protons of dimethylsiloxane per mole of the terminal methacryloyl group measured by NMR. The obtained polysiloxane graft polymer SG-1 had a number average molecular weight (Mn) of 88,000 and a molecular weight distribution (PDI = weight average molecular weight (Mw) / number average molecular weight (Mn)) of 1.78. .. Mn and Mw of the polysiloxane graft polymer are polystyrene-equivalent values measured by gel permeation chromatography (GPC) using tetrahydrofuran (THF) as a developing solvent. As a result of GPC, it was confirmed that there was no peak derived from the silicone macromonomer (1) and most of the macromonomer was incorporated into the polymer. By gas chromatography (GC), it was confirmed that no monomer component other than the silicone macromonomer (1) remained. A part of the sampled solution was left in a constant temperature layer at 180 ° C. with a duct for 30 minutes, and then heated until the constant amount was reached. The solid content obtained from the residue was 40.1%. The acid value of the polysiloxane graft polymer SG-1 was 129.1 mgKOH / g, which was almost the same as the theoretical value calculated from the amount of methacrylic acid introduced. The acid value of the polysiloxane graft polymer is 0.1N potassium hydroxide ethanol, which is obtained by diluting a part of the sampled solution with a mixed solvent of toluene / ethanol (1/5 (v / v)) and using phenolphthalein ethanol as an indicator. It was determined by titrating with a solution.

(Synthesis Examples 2-5)
Solutions of polysiloxane graft polymers SG-2 to 5 were obtained in the same manner as in Synthesis Example 1 described above, except that the types and amounts of monomer components shown in Table 1 were used. Details of the obtained polysiloxane graft polymers SG-2 to SG-2 to 5 are shown in Table 1. The details of the monomer components in Table 1 are shown below.
-Silicone macromonomer (2): methacryloyloxypropyl polydimethylsiloxane butyl, molecular weight: 2,300
-Silicone macromonomer (3): methacryloyloxypropyl polydimethylsiloxane butyl, molecular weight: 12,000
-MOMA: 2-methacryloyloxyethyl succinic acid

(Synthesis Examples 6 to 8)
A solution of the polysiloxane graft polymer SG-6 to 8 was obtained in the same manner as in Synthesis Example 1 described above, except that the types and amounts of monomer components shown in Table 2 were used. Details of the obtained polysiloxane graft polymers SG-6 to 8 are shown in Table 2. The details of the monomer components in Table 2 are shown below. The hydroxyl value is a theoretical value calculated from the charged amount. The functional group equivalent was the number of moles (mmol) of the crosslinkable functional group contained in 1 g of the polysiloxane graft polymer, and was calculated from the blending ratio.
MOI-BM: 2- [0- (1'-methylpropyrine amino) carboxyamino] ethyl methacrylate (trade name "Karenzu MOI-BM", manufactured by Showa Denko KK)
・ GMA: Glycidyl methacrylate ・ HEMA: 2-Hydroxyethyl methacrylate ・ MMA: Methyl methacrylate ・ BMA: Butyl methacrylate

(Synthesis Examples 9 to 13)
Solutions of polysiloxane graft polymers SG-9 to 13 were obtained in the same manner as in Synthesis Example 1 described above, except that the types and amounts of monomer components shown in Table 3 were used. Details of the obtained polysiloxane graft polymers SG-9 to 13 are shown in Table 3.

(Synthesis Example 14)
DPGDM 418.2 parts, 2-iodo-2-cyano-propane 1.95 parts, azobisisobutyro while blowing nitrogen into a separable flask equipped with a stirrer, cooling tube, nitrogen introduction device, and thermometer. 2.46 parts of nitrile, 0.2 part of N-iodosuccinate imide, 69.0 parts of silicone macromonomer (2), 120 parts of silicone macromonomer (3), 26 parts of HEMA, and 59.4 parts of 2EHMA were charged. Polymerization at 75 ° C. for 8 hours gave a solution of the polysiloxane graft polymer SG-14 having a solid content of 37.1%. The obtained polysiloxane graft polymer SG-14 had an Mn of 28,000 and a PDI of 1.26. As a result of GPC, it was confirmed that there was no peak derived from the silicone macromonomer and most of the macromonomer was incorporated into the polymer. The acid value of the polysiloxane graft polymer SG-14 was 40.9 mgKOH / g.

(Comparative Synthesis Examples 1 to 4)
A solution of Polysiloxane Graft Polymer Comparative SG-1 to SG-1 to 4 was obtained in the same manner as in Synthesis Example 1 described above, except that the types and amounts of monomer components shown in Table 4 were used. Details of the obtained polysiloxane graft polymer comparison SG-1 to SG-1 to 4 are shown in Table 4. In Table 4, "silicone macromonomer (4)" is methacryloyloxypropyl polydimethylsiloxane butyl (molecular weight: 900).

<Manufacturing of coating liquid>
(Formulation Examples 1 to 18, Comparative Formulation Examples 1 to 4)
Crosslinking agents according to the type of crosslinkable functional group were selected and blended with the produced polysiloxane graft polymer, respectively, to produce coating liquids 1 to 18 and comparative coating liquids 1 to 4. More specifically, first, the polysiloxane graft polymer solution was blended with the types of cross-linking agents shown in Tables 5 and 6 so as to have the functional group ratio (%) shown in Tables 5 and 6. Next, additional solvents (Tables 5 and 6) having a solid content of 20% were added and diluted to prepare each coating liquid. The viscosities of each of the produced coating liquids are shown in Tables 5 and 6. The "functional group ratio (%)" is the reaction molar ratio (%) of the functional group of the cross-linking agent to 1 mol of the cross-linking functional group of the polymer. The details of each component in Tables 5 and 6 are shown below.
-PGMAc: Propylene glycol monomethyl ether acetate-SBB: Hexamethyldiisocyanate-based blocked polyisocyanate, trade name "Duranate SBB-70P", manufactured by Asahi Kasei Corporation, PGMAc solution, active ingredient: 70%, effective NCO: 10.1%
-TETRAD: 4-functional epoxy compound, trade name "TETRAD-C", manufactured by Mitsubishi Gas Chemical Company, functional group equivalent: 98.6 g / 1 mol
-G3450: Polycarbonate diol, trade name "Duranol G3450", manufactured by Asahi Kasei Corporation, average molecular weight: 800, hydroxyl value: 140.2 mgKOH / g
162C: Polydimethylsiloxane both-terminal carboxylic acid, trade name "X-22-162C", manufactured by Shin-Etsu Chemical Co., Ltd., functional group equivalent: 2,300 g / mol
・ Diamine: 4,4'-methylenebis (cyclohexylamine)

<Manufacturing of surface treatment substrate>
(Examples 1 to 18, Comparative Examples 1 to 4)
A 2.5 cm × 7 cm silicon substrate was prepared. Using a spin coater, each coating liquid was applied onto the prepared silicon substrate under the condition of 3,000 rpm / 1 minute. After leaving it at 25 ° C. (room temperature) for 30 minutes, it was baked at 180 ° C. for 30 minutes and subjected to a curing (crosslinking) reaction to form a polymer layer (crosslinked structure) on the surface of the silicon substrate. The thickness (before swelling) of the polymer layer formed was measured using a spectroscopic ellipsometer. A silicon substrate having a polymer layer formed on its surface was immersed in silicone oil (dimethyl silicone oil, trade name "50-J", manufactured by Shin-Etsu Chemical Co., Ltd., kinematic viscosity: 50 cSt) at room temperature for 1 hour to swell the polymer layer. Then, the silicone oil is shaken off using a spin coater to form surface-treated substrates (surface-treated substrates 1 to 18, comparative surface-treated substrates 1 to 4) on which a polymer layer, which is a gel swelling material, is formed on the surface of the silicon substrate. Obtained. The thickness of the polymer layer (gel swelling body) formed using a spectroscopic ellipsometer is measured, and the linear expansion ratio (after swelling / before swelling) of the polymer layer is calculated from the measured thickness of the polymer layer before and after swelling. did. The results are shown in Tables 7 and 8.

Comparing Example 17 and Example 18, the linear expansion ratio of the polymer layer formed by using the coating liquid 18 containing the polysiloxane graft polymer SG-14 having a narrow molecular weight distribution (small PDI value) has a molecular weight distribution. It can be seen that the value was larger than the linear expansion ratio of the polymer layer formed by using the coating liquid 17 containing the wide (large PDI value) polysiloxane graft polymer SG-13. It is presumed that this is because the polysiloxane graft polymer SG-14 having a more uniform molecular weight was used, so that the network of the formed polymer layer became more uniform.

<Evaluation>
(Friction test)
The obtained substrate was subjected to a reciprocating sliding friction test according to the following conditions.
・ Measuring device: Surface tester, product name “HEIDON”, manufactured by Shinto Kagaku Co., Ltd. ・ Temperature: 25 ℃ (room temperature)
-Test method: Ball-on-disc-Ball: Made of SUS304, diameter 10 mm
-Oil used: Dimethyl silicone oil, trade name "50-J", manufactured by Shin-Etsu Chemical Co., Ltd., kinematic viscosity 50 cSt
・ Speed: 200mm / min
・ Load: 50gf
・ Reciprocating motion width: 20 mm
・ Number of round trips: 50 round trips, 100 round trips

After setting the surface-treated substrates 1 (before swelling), surface-treated substrates 1 to 18 (all after swelling), comparative surface-treated substrates 1 and 2, and the silicon substrate in the measuring device, the surface of the polymer layer (about the silicon substrate). After dropping a few drops of oil on the surface of the silicon substrate, the reciprocating sliding friction test was started, and the friction coefficient after 100 reciprocations was measured. The results are shown in Table 9. Table 9 shows the observation results and evaluations of observing the friction surface after 100 round trips.

The crosslinked structure of the present invention is useful as a material provided on the sliding surface of a sliding member constituting various devices belonging to, for example, automobiles, medical devices, robots, aerospace industry, and the like.

Claims (8)

A polysiloxane graft polymer with a number average molecular weight of 10,000 to 100,000 and
It is a cross-linked product of at least one cross-linking agent selected from the group consisting of an isocyanate-based cross-linking agent, a polyglycidyl-based cross-linking agent, a polycarboxylic acid-based compound, a polyol, and a polyamine.
The polysiloxane graft polymer has a structural unit (a) derived from a polydimethylsiloxane having a molecular weight of 1,000 to 20,000 having a (meth) acryloyl group at one end, and a hydroxyl group, a carboxy group, an isocyanate group, and a block. A structural unit (b) derived from a (meth) acrylate-based monomer having at least one crosslinkable functional group selected from the group consisting of an isociate group and a glycidyl group, and a structural unit (b) derived from a radically polymerizable vinyl-based monomer ( c) and,
The mass ratio of the structural unit (a), the structural unit (b), and the structural unit (c) in the polysiloxane graft polymer is (a) :( b) :( c) = 50 to 90: 5. A crosslinked structure of ~ 50: 0 to 45. It is swollen with at least one oil selected from the group consisting of hydrocarbon-based lubricants, polyester polyol-based lubricants, polyolefin-based lubricants, silicone-based lubricants, and alkyl halide-based lubricants.
The crosslinked structure according to claim 1, which is a gel swelling body that linearly swells 1.5 times or more as compared with that before swelling. The polydimethylsiloxane contains a first polydimethylsiloxane and a second polydimethylsiloxane having different molecular weights from each other.
The first polydimethylsiloxane has a molecular weight of 1,000 to 5,000, and the second polydimethylsiloxane has a molecular weight of 5,000 to 20,000, and the structural unit (a) is the first. The crosslinked structure according to claim 1 or 2, which comprises a structural unit (a-1) derived from the polydimethylsiloxane of 1 and a structural unit (a-2) derived from the second polydimethylsiloxane. The crosslinked structure according to any one of claims 1 to 3, wherein the polysiloxane graft polymer has a molecular weight distribution (weight average molecular weight / number average molecular weight) of 1.5 or less. The crosslinked structure according to any one of claims 1 to 4, which is a film-like molded product having a thickness of 100 nm or more. The method for producing a crosslinked structure according to any one of claims 1 to 5.
A polymerization step of polymerizing a monomer component containing the polydimethylsiloxane, the (meth) acrylate-based monomer, and the radically polymerizable vinyl-based monomer to obtain the polysiloxane graft polymer.
A method for producing a crosslinked structure, comprising a crosslinking step of crosslinking the obtained polysiloxane graft polymer with the crosslinking agent. The method for producing a crosslinked structure according to claim 6, wherein the monomer component is polymerized by a living radical polymerization method using an organic compound having an iodine atom as a polymerization initiator to obtain the polysiloxane graft polymer. It comprises a substrate and a polymer layer disposed on the surface of at least a portion of the substrate.
A surface-treated base material in which the polymer layer is a crosslinked structure according to any one of claims 1 to 5.