JP2022058689A - Seal member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a seal member having strong cut-off performance in such a degree that the seal member can endure a water pressure even in high-pressure car washing.

SOLUTION: A seal member has a photocured film produced on at least a part of the surface of a substrate using a composition containing an elastically deformable substrate, an urethane prepolymer having a photoreactive group, polythiol having a thiol group, and a tackifier resin. The photoreactive group is a group having an ethylenically unsaturated bond, the tackifier resin contains a rosin resin and/or a terpene resin, an addition amount of the tackifier resin is 0.5-20 pts.mass with respect to 100 pts.mass of the urethane prepolymer, and the urethane prepolymer is obtained by reaction a first compound having the photoreactive group that can react with the terminal of a reactant of polyisocyanate and polyol, with the reactant.

SELECTED DRAWING: None

COPYRIGHT: (C)2022,JPO&INPIT

Description

The present invention relates to a sealing member comprising an elastically deformable substrate and a film formed on at least a part of the surface of the substrate.

In architecture, civil engineering, electronics, automobiles, etc., the gaps between the members are filled with the seal members in a compressed state to perform treatments such as water stoppage, heat insulation, and sound absorption. As such a sealing member, a synthetic resin foam, a rubber foam, or the like is generally used. Since the foam has an appropriate elastic force, it can follow and adhere to the unevenness of the surface of the member to be sealed, and exhibits excellent sealing properties. Further, in order to ensure further sealing performance, as described in the following patent document, a seal having a film formed on at least a part of the surface of an elastically deformable substrate such as a synthetic resin foam or a rubber foam. Development of materials is in progress.

Japanese Patent No. 4602280 Japanese Patent No. 5746622 Japanese Unexamined Patent Publication No. 2006-83236 Japanese Unexamined Patent Publication No. 2017-197678

Here, in particular, gaskets around lamps of automobiles are used for the purpose of preventing dust and water from entering the lamps. And the adhesion between the lamp-gasket or the gasket-vehicle body is a very important characteristic. In particular, in recent years, with the spread of high-pressure washers, the water-stopping performance required for gaskets (sealing materials) has been increasing. This is because during high-pressure car washing in a general household, the sealing member may not be able to withstand the water pressure, and water may enter from the interface and cloudiness may occur in the lamp.

Therefore, an object of the present invention is to provide a sealing member having a strong water-stopping property so that the sealing member can withstand water pressure even during a high-pressure car wash.

The present invention
Elastically deformable substrate and
A photocurable film formed on at least a part of the surface of the substrate by using a composition containing a urethane prepolymer having a photoreactive group, a polythiol having a thiol group, and a tackifier resin was provided. It is a sealing member
The photoreactive group is a group having an ethylenically unsaturated bond.
The tackifier resin contains a rosin resin and / or a terpene resin.
The amount of the tackifier resin added is 0.5 to 20 parts by mass with respect to 100 parts by mass of the urethane prepolymer.
The urethane prepolymer was obtained by reacting a reaction product of polyisocyanate and a polyol with a first compound having a photoreactive group capable of reacting with the terminal of the reaction product.
The thiol-ene ratio between the polythiol and the urethane prepolymer is 0.5 to 2.0.
The average functional group of the polythiol is trifunctional or higher,
The urethane prepolymer is a sealing member having a weight average molecular weight of 2,500 to 70,000.
Here, the urethane prepolymer reacts the reaction product of the polyisocyanate and the polyol with the first compound and the second compound having no photoreactive group capable of reacting with the terminal of the reaction product. It may be obtained by making it.
Further, the molar ratio of the first compound / the second compound at the time of producing the urethane prepolymer may be 1 to 10.
Further, the molar ratio of the first compound / the second compound may be 2 to 8.
Further, the amount of the tackifier resin added may be 1 to 15 parts by mass with respect to 100 parts by mass of the urethane prepolymer.

According to the present invention, it is possible to provide a sealing member having a strong water-stopping property such that the sealing member can withstand water pressure even during a high-pressure car wash.

FIG. 1 is a diagram showing an outline of a manufacturing example of a seal member according to the present embodiment. FIG. 2 is a diagram showing a method for measuring the adhesion strength of a coated steel sheet in this embodiment. FIG. 3 is a diagram showing an evaluation method for water-stopping evaluation in this example.

≪Seal member≫
The sealing member according to the present invention uses a composition containing a substrate made of elastically deformable closed cells; a urethane prepolymer having a photoreactive group, polythiol, and a tackifier resin, and the surface of the substrate. With a photocurable film made in at least a portion of. Hereinafter, each component will be described first.

(Hypokeimenon)
Examples of the elastically deformable substrate include foams, specifically, rubber foams, synthetic resin foams, and the like. For example, rubber sponge, polyurethane foam, polyolefin foam and the like can be mentioned. Even when the foam (open-cell foam) that is in a communicative state due to the broken or penetrating foam film of the foam is used as the substrate, the water-stopping effect is achieved by being compressed between the members and used. Water stoppage may not be sufficient depending on the application. Therefore, it is preferable that the substrate is a foam made of closed cells (closed cell foam) (as the closed cell foam, some bubbles may be in a communicative state). As the substrate, a rubber sponge made of a closed cell foam or a polyolefin foam is particularly preferable. Here, the "elastically deformable" substrate refers to a substrate having general elastic properties, and more specifically, it is deformable when an external force is applied and is unloaded with external stress. It refers to a substrate that has elasticity that tries to return to its original dimensions. The degree of elasticity (further, density, hardness, etc.) may be changed according to the intended use. Further, the surface of the substrate may be subjected to surface treatment such as primer treatment.

The shape of the substrate is not particularly limited including the dimensions and the like. For example, a sheet shape may be used, but a three-dimensional shape (curved surface shape, columnar shape, cylindrical shape, etc.) may be used, and a desired shape may be used depending on the intended use and application target.

(Film)
-The structural film is formed on at least a part of the surface of the substrate. Further, it may be formed on either one side or both sides of the substrate.

More specifically, the film is formed directly (in close contact) with a portion of at least one surface of the substrate and a portion of the opposite surface. In this seal member, when the seal member is used and is sandwiched between the members to be sealed and pressed, the film is positioned at a part or all of the contact points between the seal member and the member to be sealed. I'm assuming. According to this seal member, when such a usage method (for example, a gasket or the like) is assumed, by adopting the above-mentioned film, the follow-up adhesion between the film and the member to be sealed is further improved and the water stopping property is improved. It is possible to make it. From such a viewpoint, it is conceivable to provide a film on the entire surface of the substrate.

As a place where the film is formed on the substrate, "at least a part of one surface of the substrate and at least a part of the opposite surface" is a contact point between the present sealing member and the sealed member as described above. Part (or all) on the substrate is assumed. Therefore, for example, when the substrate is in the form of a sheet, a part of the front surface and a part of the back surface of the substrate are shown as the film forming location, but when the substrate is columnar, a part of the surface of the substrate. And a part of the surface on the back side thereof (in the case of a columnar shape, a part including a part on a certain bus and a part on the bus located on the opposite side, etc.), or a substrate. When is tubular or the like (and is used to be sandwiched between the inner side surface and the outer side surface of the cylinder by the sheet to be covered), it may be a part of the inner side surface and a part of the outer side surface of the substrate.

The thickness of the film may be appropriately adjusted according to the intended use and the like, and is not particularly limited, but may be, for example, 10 to 500 μm.

≪Manufacturing method of seal member≫
<Ingredients>
First, each raw material component in the photocurable film-forming composition used in manufacturing the sealing member will be described in detail.

(Ingredient component / Urethane prepolymer)
The urethane prepolymer is a urethane prepolymer having a photoreactive group. Hereinafter, the urethane prepolymer will be described in detail. Here, the photoreactive group is a functional group that can be crosslinked by irradiation with X-rays, electron beams, ultraviolet rays, visible light and the like. More specifically, the urethane prepolymer can be added to the reaction product of the polyisocyanate and the polyol with the first compound (the compound having the photoreactive group capable of reacting with the terminal of the reaction product), and more preferably further. It was obtained by reacting with a second compound (a compound capable of reacting with the terminal of the reactant and having no photoreactive group). Hereinafter, various raw materials used in producing the urethane prepolymer will be described first.

-Polyisocyanate The "polyisocyanate" used for the synthesis of the urethane prepolymer may be a compound having two or more isocyanate groups in one molecule, and may be a compound usually used as a raw material for the urethane prepolymer. For example, aromatic isocyanates, aliphatic isocyanates, alicyclic isocyanates and the like can be mentioned. Examples of the aromatic isocyanate include tolylene diisocyanate (TDI), 4,4'-diphenylmethane diisocyanate (MDI), polypeptide MDI (crude MDI), xylylene diisocyanate, 1,5-naphthalene diisocyanate and the like. Examples of the aliphatic isocyanate include hexamethylene diisocyanate, isopropylene diisocyanate, and methylene diisocyanate. Examples of the alicyclic isocyanate include cyclohexane-1,4-diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate (hydrogenated MDI) and the like. One or a combination of two or more of these various polyisocyanates can be used as a raw material for the urethane prepolymer.

-Polyol The "polyol" used in the synthesis of the urethane prepolymer may be a compound having two or more hydroxyl groups in one molecule and may be a compound usually used as a raw material for the urethane prepolymer. For example, polyester polyol, polyether polyol and the like can be mentioned. Some polyester polyols are obtained by a condensation reaction between a polyhydric alcohol and a polyvalent carboxylic acid. Examples of the polyhydric alcohol include ethylene glycol, propylene glycol, butanediol, butylene glycol, glycerin, and trimethylolpropane, and these can be used alone or in combination of two or more. Examples of the polyvalent carboxylic acid include glutaric acid, adipic acid, maleic acid, terephthalic acid, isophthalic acid and the like, and these can be used alone or in combination of two or more. Further, a polyester polyol obtained by ring-opening condensation of caprolactone, methylvalerolactone and the like can be mentioned. Further, as the polyether polyol, for example, addition polymerization of an oxide such as ethylene oxide, propylene oxide, trimethylene oxide and butylene oxide to a polyhydric alcohol such as ethylene glycol, propylene glycol, diethylene glycol, glycerin, trimethylolpropane and sorbitol. The ones that were made to be mentioned. It is possible to use one or a combination of two or more of these various polyols as a raw material for the urethane prepolymer.

-Catalyst It is preferable to use a catalyst in the synthesis of urethane prepolymer. The catalyst may be any catalyst that is usually used as a raw material for urethane prepolymers, and examples thereof include amine-based catalysts and organometallic catalysts. Examples of the amine-based catalyst include triethylenediamine, diethanolamine, dimethylaminomorpholine, N-ethylmorpholine and the like. Examples of the organometallic catalyst include sternas octoate, dibutyltin dilaurate, lead octenoate, potassium octylate and the like. One or a combination of two or more of these various catalysts can be used as a raw material for the urethane prepolymer.

-First compound The first compound is a compound having a photoreactive group capable of reacting with the terminal of a reaction product of polyisocyanate and a polyol. Here, the "photoreactive group" is an ethylenically unsaturated bond (-C = C-). Examples of such a "photoreactive group" include a vinyl ether group (CH ₂ = CH-O-), a methacrylate group (CH ₃ CH = CH ₂ -COO-), and an acrylate group (CH ₂ = CH ₂ -COO-). And allyl ether groups (CH ₂ = CH _— O—CH2-) are suitable. Further, the first compound having the photoreactive group may be any one that can be added to the terminal of the urethane prepolymer (for example, the isocyanate group of the urethane prepolymer), for example, 2-hydroethyl methacrylate. Allyl ether glycol, hydroxyethyl allyl ether, 2-hydroxyethyl vinyl ether, diethylene glycol monovinyl ether, 4-hydroxybutyl vinyl ether, hydroxyethyl acrylate, hydroxypropyl acrylate, 4-hydroxybutyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxyethyl acrylate , 2-Hydroxypropyl methacrylate and the like.
A monofunctional active hydrogen compound is preferred in order to enhance the reaction activity. Moreover, you may use 1 type or 2 or more types of the first compound.

-Second compound The second compound is a compound that can react with the end of the reaction product of polyisocyanate and the polyol, can react with the end of the reaction product, and does not have the photoreactive group. Therefore, since the second compound does not participate in the cross-linking reaction, the degree of cross-linking is low, the formed film has high flexibility, and the adhesion to the adherend is improved. Therefore, by using such a second compound, it is possible to obtain higher water stopping property. Such a second compound may be one that can be added to the terminal of the urethane prepolymer (for example, the isocyanate group of the urethane prepolymer) and does not have the photoreactive group. For example, linear, branched or cyclic monohydric alcohols include methanol, ethanol, propanol, butanol, isobutyl alcohol, tert-butyl alcohol, pentanol, isopentyl alcohol, neopentyl alcohol, hexanol, 2-methyl-1-. Pentanol, octanol, 2-ethyl-1-hexanol, 3,5,5-trimethyl-1-hexanol, decanol, undecanol, 1-dodecanol, isooctadecanol, octadecanol, docosanol, 14-methylhexadecanol, cyclo Hexanol, methylcyclohexanol, 2-ethylhexyl glycol and the like can be mentioned, and examples of the glycol ethers include ethylene glycol monomethyl ether, diethylene glycol monomethyl ether, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether and ethylene glycol monohexyl ether. .. A monofunctional active hydrogen compound is preferred in order to enhance the reaction activity. Further, one kind or two or more kinds of the second compound may be used.

-Mole ratio of first compound / second compound (blending ratio at the time of preparation)
When the second compound is also used as a raw material, the molar ratio of the first compound / the second compound at the time of producing the urethane prepolymer is preferably 1 to 10, more preferably 2 to 9. More preferably, it is 3 to 7. By setting the molar ratio in this range, it is possible to obtain higher water stopping property.

Further, the weight average molecular weight (Mw) of the urethane prepolymer is 2,500 to 70,000, preferably 3,000 to 40,000, and more preferably 3,000 to 20,000. be. By setting the molecular weight in this range, it is possible to obtain higher water stopping property. The weight average molecular weight can be determined by gel permeation chromatography (GPC) measurement in terms of a standard substance such as styrene.

The urethane prepolymer (particularly when both the first compound and the second compound are used as raw materials) has (1) "photoreactive groups" derived from the first compound at both ends of the reaction product of the polyisocyanate and the polyol. , (2) Those having residues (non-photoreactive groups) derived from the second compound at both ends of the reaction product of polyisocyanate and polyol, (3) Reaction product of polyisocyanate and polyol. Those having a "photoreactive group" derived from the first compound and a residue (non-photoreactive group) derived from the second compound at both ends are understood to be the main components.

(Ingredient component / Adhesive-imparting resin)
The tackifier resin includes a rosin resin and / or a terpene resin. Here, examples of the rosin resin include rosin, hydrogenated rosin, disproportionated rosin, and esterified rosin. Examples of the terpene resin include non-modified terpene resin, terpene phenol resin, aromatic-modified terpene resin, and hydrogenated terpene resin.

(Ingredient component / Polythiol)
The polythiol may be any polythiol as long as the average functional group is trifunctional or higher. For example, examples of polythiol include esters of mercaptocarboxylic acid and polyhydric alcohol, aliphatic polythiol, and aromatic polythiol. Examples of the mercaptocarboxylic acid in the ester of the mercaptocarboxylic acid and the polyhydric alcohol include thioglycolic acid and meltcaptopropionic acid, and the polyhydric alcohol includes ethylene glycol, propylene glycol, 1,4-butanediol and 1,6. -Hexanediol, glycerin, trimethylolpropane, pentaerythritol, sorbitol and the like can be mentioned. As esters of mercaptocarboxylic acid and polyhydric alcohol, for example, trimethylolpropanetris (3-mercaptopropionate), pentaerythritol tetrakis (3-mercaptopropionate), tetraethylene glycol bis (3-mercaptopropionate) , Dipentaerythritol hexa (3-mercaptopropionate) and the like. Examples of the aliphatic polythiol and the aromatic polythiol include ethanedithiol, propandithiol, hexamethylenedithiol, decamethylenedithiol, trilen-2,4-dithiol, xylenedithiol and the like. When using trifunctional or higher functional polythiol, one type may be used, but when bifunctional polythiol is used, tetrafunctional or higher functional polythiol is used in combination so that the average functional group of the polythiol present in the system is trifunctional or higher. do.

By mixing the urethane prepolymer with polythiol having a trifunctional or higher average functional group and irradiating it with light, it is possible to form a film on at least a part of the surface of the substrate by the ential reaction. .. By using such a thiol, it becomes possible to form a film having a high water-stopping property.

(Ingredient component / Photopolymerization initiator)
In order to effectively carry out a photopolymerization reaction between a urethane prepolymer having a photoreactive group and a thiol group, it is possible to include a photopolymerization initiator in the compounding raw material. Examples of the photopolymerization initiator include acetophenone-based, benzophenone-based, and thioxanthone-based compounds. Examples of the acetophenone system include 2,2-dimethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, 4- (1-t-butyldioxy-1-methylethyl) acetophenone, and 2-methyl-1- [4-. (Methylthio) Phenyl] -2-morpholino-propane-1-one and 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1, diethoxyacetophenone, 2-hydroxy-2-methyl- 1-Phenylpropan-1-one, benzyldimethylketal, 4- (2-hydroxyethoxy) phenyl- (2-hydroxy-2-propyl) ketone, 1-hydroxycyclohexylphenylketone, 2-hydroxy-2-methyl-1 -[4- (1-Methylvinyl) phenyl] propanone oligomer and the like can be mentioned. Examples of the benzophenone system include 4- (1-t-butyldioxy-1-methylethyl) benzophenone, 3,3', 4,4'-tetrakis (t-butyldioxycarbonyl) benzophenone, and o-benzoylmethylbenzoate. , 4-Phenylbenzophenone, 4-Benzoyl-4'-methyl-diphenylsulfide, 3,3', 4,4'-tetra (t-butylperoxylcarbonyl) benzophenone, 2,4,6-trimethylbenzophenone, 4- Examples thereof include benzoyl-N, N-dimethyl-N- [2- (1-oxo-2-propenyloxy) ethyl] benzenemethanamineium bromide, (4-benzoylbenzyl) trimethylammonium chloride and the like. Examples of the thioxanthone system include 2,4-dimethylthioxanthone, 2,4-diisopropylthioxanthone, 2-chlorothioxanthone, 2-isopropylthioxanthone, 4-isopropylthioxanthone, 2,4-diethylthioxanthone, and 2,4-dichloro. Examples thereof include thioxanthone, 1-chloro-4-propoxythioxanthone, 2- (3-dimethylamino-2-hydroxy) -3,4-dimethyl-9H-thioxanthone-9-onmesochloride and the like.

(Ingredients / Remarks)
Each of the above raw material components may be used alone or in combination of two or more.

<Mixing>
Next, the blending ratio of the raw material components in the film-forming composition used in manufacturing the sealing member and the like will be described in detail.

(Formulation / Urethane prepolymer and adhesive resin)
The compounding ratio of the urethane prepolymer and the tackifier resin in the film-forming composition is 0.5 to 20 parts by mass, preferably 0.75 to 15 parts by mass with respect to 100 parts by mass of the urethane prepolymer. It is more preferably 1 to 10 parts by mass. By setting the compounding ratio in this range, it is possible to obtain higher water stopping property.

(Formulation / thiol-en ratio)
The thiol-ene ratio of the polythiol to the urethane prepolymer in the film-forming composition is 0.5 to 2.0, preferably 0.65 to 1.5, and more preferably 0.8 to 0.8. It is 1.2. By setting the thiol-ene ratio in this range, it is possible to obtain higher water stopping property. The thiol-ene (double bond) ratio can also be indexed as a thiol index. The thiol index is a value obtained by multiplying the ratio of the number of moles of thiol groups in the thiol compound to the number of moles of double bond groups by 100, and is 50 to 200.

(Formulation / Photopolymerization Initiator)

The content of the photopolymerization initiator is preferably 0.01 to 5 parts by weight, more preferably 0.1 to 3 parts by weight, per 100 parts by weight of the urethane prepolymer. When the content of the photopolymerization initiator is within such a range, the photopolymerization initiation ability is sufficient, the raw material is rapidly polymerized, the polymerization is not excessively promoted, and the cross-linking density is high. It is possible to prevent excessive formation and non-uniform formation of the crosslinked structure.

(Mixing / Other)
The film-forming composition may contain known additives and diluents in addition to the above, but the urethane prepolymer and the polythiol having a thiol group are the main components in the raw material (composition). More specifically, the total blending amount of these is preferably 90% by weight, more preferably 95% by weight, based on the raw material (composition).

<Process>
Next, a method for producing the film-forming composition and a method for producing the seal member using the substrate and the film-forming composition will be described in detail.

(Process / Method for manufacturing a film-forming composition)
The composition for forming the present film is obtained by stirring and mixing the above-mentioned raw materials at the above-mentioned compounding ratio.

(Process / Manufacturing method of base material)
FIG. 1 is a diagram showing an outline of a manufacturing example of a seal member according to the present embodiment. As long as the manufacturing process of this sealing member includes an adhesion step of adhering a raw material for film formation to a substrate and an irradiation step of irradiating the adhered raw material with light and curing the raw material by a photopolymerization reaction. {For example, a cleaning step, a drying step, a processing step (molding step), and the like may be included}. Hereinafter, an example of a method for manufacturing the seal member will be described. Since the substrate can be manufactured according to a known manufacturing method (foaming method or curing method), the description thereof will be omitted.

The above-mentioned film-forming composition (mixed raw material) is applied on a film or the like having good permeability with a predetermined film thickness. Next, the surface of the elastically deformable substrate is pressure-bonded onto the applied mixed raw material (adhesion step). At this time, the liquid mixed raw material is appropriately blended with the surface of the substrate. Then, in the presence of air, the applied mixed raw material is irradiated with light (for example, ultraviolet rays) from below the film, so that the mixed raw material is cured and a film is formed (irradiation step). As a result, the raw material is cured in a state where the liquid raw material and the surface of the substrate are appropriately blended, and the adhesion between the substrate and the film is improved. Further, the adhesion step of adhering the mixed raw material to the opposite surface (the surface on which the film is not formed) of the substrate having the film formed on one side is similarly performed, and then the irradiation step of curing the mixed raw material is similarly performed. A sealing member having a film is formed on both sides (front surface and back surface) of the substrate. The method of forming a film on both sides of the substrate is not limited to this, and the mixed raw material is adhered to at least a part of the front surface and at least a part of the back surface of the substrate, and the mixed raw material is cured at once. May be.

When a substrate made of a predetermined material, specifically, for example, a substrate made of ethylene propylene diene rubber (EPDM) is used as the elastically deformable substrate, a primer is applied to the adhesion surface of the substrate to the mixed raw material. By performing the treatment, it becomes possible to ensure the adhesion between the substrate and the film. Examples of the primer treatment include blast treatment, chemical treatment, degreasing, flame treatment, oxidation treatment, vapor treatment, corona discharge treatment, ultraviolet irradiation treatment, plasma treatment, ion treatment and the like.

The irradiation amount of light (for example, ultraviolet rays) when curing the mixed raw material is not limited as long as the mixed raw material can be cured, but is, for example, 200 to 1800 mJ / cm ² (365 nm integrated light amount). Is preferable. The irradiation time is also not particularly limited and can be appropriately changed according to the mixed raw material to be used and the amount of light irradiation.

Further, when applying the mixed raw material to the film, it is preferable to use a coating device such as a comma coater, a die coater, or a gravure coater. In particular, it is preferable to use a die coater because the viscosity of the viscous fluid can be adjusted by adjusting the temperature of the viscous fluid at the time of coating.

≪Use≫
The sealing member according to the present invention is useful as a sealing member used in construction, civil engineering, electronics, automobiles, etc., in which gaps between the members are filled and compressed. In particular, a sealing material for vehicle lamps of automobiles, motorized bicycles, railroad vehicles, etc., which are required to have high water stopping property (seal material for modular parts constituting vehicle lamps and sealing the lamp and housing). It is suitable as.

≪Preparation of urethane prepolymer≫
According to Table 1, polyisocyanate was placed in a separable flask having a capacity of 1 liter, and the polyol was added dropwise with stirring while flowing nitrogen. After completion of the dropping, a catalyst (DBTDL: dibutyltin dilaurate 0.3 g) was added while paying attention to the temperature rise. After reacting for 2 hours and sample ringing, the isocyanate group content was prepolymer A to G: 3.0 to 4.0%, prepolymer H: 0.6 to 0.8%, prepolymer I: 0.4 to. It was confirmed that the content was 0.6%, prepolymer J: 0.3 to 0.5%, and prepolymer K: 15 to 16%. The isocyanate content was measured according to the method based on JIS Z1603-1: 2007 (polyurethane raw material aromatic isocyanate test method). Next, according to Table 1, vinyl ether or methacrylate and monool were added dropwise and reacted for 2 hours. After the reaction, sample ring was performed to confirm that the isocyanate group content was 0.1% or less. When the isocyanate group content is 0.1% or less, the reaction is completed and the product is a urethane prepolymer. The raw materials used to prepare the prepolymer are shown below.
Polyol a: Polypropylene glycol (PPG), trade name Actol D1000 (Mw: 1000), Mitsui Chemicals, Inc.
Polyol b: Polycarbonate diol (PCD), trade name: UP100 (Mw: 1000), Ube Kosan Co., Ltd.
Polyol c: Polypropylene glycol (PPG), trade name: Preminol S4012 (Mw: 12000), Asahi Glass Co., Ltd.
Polyol d: Polypropylene glycol (PPG), trade name: Preminol S4318 (Mw: 18000), Asahi Glass Co., Ltd.
Polyol e: Polypropylene glycol (PPG), trade name: Sanniks PP-200 (Mw: 200), Sanyo Chemical Industries, Ltd.
Monool: 2-ethylhexylglycol (Mw: 174.3), Nippon Emulsifier Co., Ltd.
Polyisocyanate: TDI, trade name: Luplanate T-80 (Mw: 174.2), BASF vinyl ether: hydroxybutyl vinyl ether (Mw: 116.2), Nippon Carbide Co., Ltd.
Methacrylate: 2-Hydroxyethyl methacrylate (Mw: 130.1), Nippon Shokubai Co., Ltd.

<< Preparation of film-forming composition >>
According to Tables 2 and 3, the urethane prepolymer, polythiol, tackifier resin and photopolymerization initiator were mixed at 80 ° C. for 5 minutes to obtain a film-forming composition. Here, in Table 2, the "photoreactive group" means the first compound (vinyl ether, methacrylate) having a photoreactive group, and the "non-photoreactive group" does not have a photoreactive group. It means the second compound (monool). Further, in Examples 1 and 2, since the second compound is not used as the charging raw material, the items of "photoreactive group" / "non-photoreactive group" are not provided. The raw materials for the film-forming composition are shown below.
Thiol A: Trimethylolpropane Tris, trade name: TMMP (Mw: 398.5), SC Organic Chemistry Co., Ltd.
Thiol B: Pentaerythritol Tetrakis, Trade name: PEMP (Mw: 488.6), SC Organic Chemistry Co., Ltd.
Thiol C: Dipentaerythritol Hexakis, Product name: DPMP (Mw: 783.0), SC Organic Chemistry Co., Ltd.
Thiol D: Butanediol bisthiopropionate, trade name: BDTP (Mw: 266.4), Yodo Kagaku Co., Ltd.
Adhesive-imparting resin A: Rosin ester, trade name: Super ester A100, Arakawa Chemical Industry Co., Ltd.
Adhesive-imparting resin B: Terpene phenol, trade name: YS Polystar T-100, Yasuhara Chemical Co., Ltd.

≪Manufacturing of sealing material≫
The prepared film-forming composition was applied to the surface of the release-treated PET film (thickness 38 μm) so as to have a thickness of 100 μm. Next, the coated composition for forming a film and N-148 (manufactured by Inoac Corporation), which is a foam rubber of a natural rubber / styrene-butadiene rubber blend system having a thickness of 4.8 mm, are bonded and coated. The film-forming composition was cured by irradiating light (wavelength: 365 nm, irradiation amount 600 mJ / cm ² ) from the PET film side to obtain a foam rubber sheet having a single-sided film.
Subsequently, the prepared film-forming composition was applied to the surface of a separately prepared release-treated PET film (thickness 38 μm) so as to have a thickness of 100 μm. The coated film-forming composition and the foamed rubber surface of the foamed rubber sheet of the one-sided film are bonded together, and the bonded film-forming composition is further irradiated with light from the PET film side (wavelength: 365 nm, irradiation amount 600 mJ). / Cm ² ) and cured to obtain a sealing material for a foam rubber sheet having a double-sided coating having a thickness (excluding PET film) of 5 mm.

≪Measurement method≫
<Measurement of adhesion strength of painted steel sheet>
Release paper on both sides of the sealing material of each example and comparative example is removed, processed into a test sample with a thickness of 5 mm × φ50 mm, and double-sided tape (Nitto Denko No. 500) is used on an aluminum plate with a thickness of 3 mm × φ50 mm. And pasted together. The coated steel sheet was prepared by painting and drying it with a polyester resin and a melamine resin paint (Neoamilac 6000 manufactured by Kansai Paint Co., Ltd.) on the surface of a high-strength steel having a thickness of 1 mm, and a through hole of φ20 mm was provided in the center.
The test sample was placed so that the center of the test sample and the center of the through hole of the coated steel sheet coincided with each other.
Then, a load was applied so that the compression rate was 50%, and the mixture was allowed to stand for 5 minutes. After standing, it was completely unloaded and left to stand for another 15 minutes.
After standing still, a load transmission rod of φ15 mm was placed in the through hole of the painted steel sheet at 5 mm / min. The load when the test sample was peeled off from the coated steel sheet was taken as the adhesion strength of the coated steel sheet.

<Water stoppage evaluation>
The release papers on both sides of the sealing material of each Example and Comparative Example were removed and processed into an annular shape having an outer diameter of 60 mm, an inner diameter of 40 mm, and a thickness of 5 mm. The test sample was placed in contact with the painted steel sheet as shown in FIG.
The coated steel sheet was prepared by painting and drying a polyester resin and a melamine resin paint (Neo Amylac 6000 manufactured by Kansai Paint Co., Ltd.) on the surface of a high-strength steel having a thickness of 1 mm.
Subsequently, a spacer having a thickness of 2.5 mm was placed around the test sample, and the acrylic plate was fixed by compressing the test sample with an acrylic plate so as to have a compression ratio of 50%.
After setting the test sample, it was allowed to stand for 24 hours and the evaluation was started. After filling the inner circle of the annular test sample with distilled water, air was supplied and a static pressure of 5 kPa was applied. This state was maintained for 5 minutes, and if there was no water leakage, further air was supplied, 5 kPa was added, and the temperature was adjusted to 10 kPa and maintained for 5 minutes. This operation was repeated until a water leak occurred, and the pressure at which the water leak occurred was measured.
The water stoppage evaluation was based on the following evaluation criteria.
⊚: Pressure for water leakage is 50 kPa or more ○: Pressure for water leakage is 30 kPa or more and less than 50 kPa Δ: Pressure for water leakage is 10 kPa or more and less than 30 kPa ×: Pressure for water leakage is less than 10 kPa

<Reworkability (presence or absence of film residue)>
When the test sample after the water-stopping test in each Example and Comparative Example was removed from the coated steel sheet and the acrylic plate, it was confirmed whether or not a film residue was present at the position where the test sample of the coated steel plate and the acrylic plate was attached. bottom. The evaluation was performed visually, and those without a residue were evaluated as ◯, and those with a residue were evaluated as x.

≪Evaluation result≫
The performance of the examples and comparative examples (painted steel sheet adhesion, water-stopping evaluation, reworkability, comprehensive evaluation) was evaluated. The results are shown in Tables 2 and 3. From the results, the effect of the present invention can be understood.

10: Painted steel plate adhesion strength measuring instrument 11 and 21: Test sample 12: Aluminum plate 13, 23: Painted steel plate 14: Height adjustment table 15: Load transfer rod 20: Water-stopping evaluator 22: Acrylic plate 24: Water Air inlet fitting 25: Spacer

Claims (5)

With an elastically deformable substrate;
A photocurable film formed on at least a part of the surface of the substrate using a composition containing a urethane prepolymer having a photoreactive group, polythiol, and a tackifier resin;
It is a seal member equipped with
The photoreactive group is a group having an ethylenically unsaturated bond.
The tackifier resin contains a rosin resin and / or a terpene resin.
The amount of the tackifier resin added is 0.5 to 20 parts by mass with respect to 100 parts by mass of the urethane prepolymer.
The urethane prepolymer was obtained by reacting a reaction product of polyisocyanate and a polyol with a first compound having a photoreactive group capable of reacting with the terminal of the reaction product.
The thiol-ene ratio between the polythiol and the urethane prepolymer is 0.5 to 2.0.
The average functional group of the polythiol is trifunctional or higher,
A sealing member having a weight average molecular weight of 2,500 to 70,000 of the urethane prepolymer. The urethane prepolymer is obtained by reacting a reaction product of polyisocyanate and a polyol with the first compound and the second compound capable of reacting with the terminal of the reaction product and having no photoreactive group. The seal member according to claim 1, which is the same as that of the above. The sealing member according to claim 2, wherein the molar ratio of the first compound / the second compound at the time of producing the urethane prepolymer is 1 to 10. The sealing member according to claim 2 or 3, wherein the molar ratio of the first compound / the second compound is 2 to 8. The sealing member according to any one of claims 1 to 4, wherein the amount of the tackifier resin added is 1 to 15 parts by mass with respect to 100 parts by mass of the urethane prepolymer.

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