WO2018084299A1

WO2018084299A1 - Seal member and method of manufacturing seal member

Info

Publication number: WO2018084299A1
Application number: PCT/JP2017/040002
Authority: WO
Inventors: 秀隆飯塚; 稔生方; 後藤　章秀
Original assignee: 株式会社イノアックコーポレーション; 株式会社イノアック技術研究所
Priority date: 2016-11-07
Filing date: 2017-11-06
Publication date: 2018-05-11
Also published as: CN109906260B; CN109906260A

Abstract

Provided is a seal member that yields sufficient tightness of bond between a foam body and a surface coating provided on the surface of the foam and constituting an adhesive surface, is capable of conforming and fitting tightly to protrusions and recesses on the surface of a sealed member, is highly water-tight, and exhibits superior reworkability. This seal member is formed by providing, on at least part of one surface of a foam substrate and at least part of the reverse surface thereof, a coating made using a composition containing a urethane prepolymer and a thiol-group-containing polythiol.

Description

Seal member and method for manufacturing seal member

The present invention relates to a sealing member having a high water-stopping property and a manufacturing method of the sealing member.

When it is desired to avoid the penetration of dust and wind and rain between members, generally, a method of improving the air tightness and water tightness by arranging a seal member in the gap between the members is taken. For example, foam rubber is used as a gasket around the lamps of automobiles. More specifically, in the prior art, foamed rubber having a double-sided tape bonded on one side is punched into a certain shape and bonded to a lamp part and assembled to an automobile body (for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2001-35216

However, when the double-sided tape is not used for the assembly, the conventional gasket as described above may not easily follow and adhere to the automobile body due to the settling (stress relaxation) of the foamed rubber after the assembly. . Therefore, dust and water may infiltrate due to vibration and the like, and it has been difficult to maintain a high water-stopping property.

In addition, when using double-sided tape when assembling, the conventional gasket as described above has a problem in reworkability, and it is difficult to rework when misalignment or the like occurs during bonding. It is possible.

The present invention has been made in view of the above points, and an object of the present invention is to provide a sealing member that can follow and adhere to irregularities on the surface of a member to be sealed, has high water-stopping properties, and is excellent in reworkability.

The present invention (1)
A substrate that is an elastically deformable foam;
Using a composition comprising a urethane prepolymer having at least one of an allyl ether group, a vinyl ether group, and a (meth) acrylate group as a terminal functional group, and a polythiol having a thiol group, at least one surface of the substrate is used. A seal member provided with a coating formed on at least a part of a part and the opposite surface.
The present invention (2)
In the sealing member according to the invention (1), the average number of functional groups of thiol groups of the polythiol is 2.5 to 6.0.
The present invention (3)
The ratio of the total equivalent number of thiol groups of the polythiol to the total equivalent number of allyl ether groups, vinyl ether groups and (meth) acrylate groups of the urethane prepolymer is 0.7 to 2.5. It is the sealing member of the said invention (1) or the said invention (2).
The present invention (4)
The sealing member according to any one of the inventions (1) to (3), wherein a weight percentage of the terminal functional group in the urethane prepolymer is 0.5 to 35%. .
The present invention (5)
The sealing member according to any one of the inventions (1) to (4), wherein the base is a foam made of closed cells.
The present invention (6)
The seal member according to any one of the inventions (1) to (5), wherein the seal member is for a vehicle lamp.
The present invention (7)
The invention (1) to the invention (1), wherein the substrate is an ethylene-α-olefin-nonconjugated diene terpolymer foam made of closed cells and having a surface layer formed by plasma treatment. The seal member according to any one of 6).
The present invention (8)
One of the base | substrates which are the foams which can be elastically deformed from the raw material containing the urethane prepolymer which has at least 1 of an allyl ether group, a vinyl ether group, and a (meth) acrylate group as a terminal functional group, and the polythiol which has a thiol group Attaching to at least part of the surface and at least part of the opposite surface;
And an irradiation step of irradiating the raw material attached in the attachment step with light.
Here, in the invention (8),
The average number of functional groups of the polythiol is preferably 2.5 to 6.0,
The ratio of the total number of equivalents of thiol groups of the polythiol to the total number of equivalents of allyl ether groups, vinyl ether groups and (meth) acrylate groups of the urethane prepolymer is preferably 0.7 to 2.5. And
The urethane prepolymer preferably has a weight average molecular weight of 1,000 to 30,000,
It is preferable that the substrate is a foam made of closed cells,
It is preferable that the seal member is for a vehicle lamp.
The present invention (9)
A primer step of forming a surface layer by plasma treatment on at least a part of one surface of the substrate that is the elastically deformable foam and at least a part of the opposite surface, before the attaching step, It is a manufacturing method of the sealing member given in invention (8).

According to the present invention, it is possible to provide a sealing member that can follow and adhere to the unevenness of the surface of the member to be sealed, has high water-stopping properties, and is excellent in reworkability.

Furthermore, the sealing member of the present invention can be used as a dual use even when the sealed member has left and right (or up and down) by having a surface film that becomes an adhesive surface on both sides of the foam, and management after processing Becomes easy.

It is a side view which shows the instrument for evaluating the water stop property of a sealing member. It is a top view which shows the instrument for evaluating the water stop of a sealing member.

Next, the “seal member” and “seal member manufacturing method” according to the present invention will be described. It should be noted that the present invention is not limited to the above description, and various modifications can be made in a mode that can achieve the object of the present invention.

<<< Seal Member >>>
The “seal member” of the present invention includes a base that is an elastically deformable foam, a urethane prepolymer having at least one of an allyl ether group, a vinyl ether group, and a (meth) acrylate group as a terminal functional group, and a thiol group. And a film (water-resistant film) formed on a part of at least one surface of the substrate and a part of the opposite surface thereof using a composition containing polythiol having the above.

<< Structure: Substrate >>
Examples of the elastically deformable substrate include rubber foam and synthetic resin foam. For example, rubber sponge, polyurethane foam, polyolefin foam and the like can be mentioned. Further, specific examples of rubber sponge include ethylene-α-olefin-nonconjugated diene terpolymer sponge (foam) such as ethylene propylene diene rubber (EPDM) sponge, CR sponge, natural rubber sponge, NBR sponge, Examples thereof include fluororubber sponge and silicone sponge. Even when the foam film of the foam is broken or penetrated and the foam (open cell foam) is in a communicating state as a base, it is water-tight by being compressed between members. Depending on the case, the water stoppage may not be sufficient. Therefore, the base is preferably a foam made of closed cells (closed cell foam) (as the closed cell foam, some of the bubbles may be in communication). The base is preferably a rubber sponge made of closed cell foam (specifically, EPDM sponge or natural rubber sponge) or polyolefin foam. Here, the “elastically deformable” substrate refers to a substrate having a general elastic property. Specifically, the substrate can be deformed when an external force is applied, and the external stress is unloaded. In this case, it refers to a substrate that works to return to its original dimensions. In addition, what is necessary is just to change the degree of elasticity (a density, hardness, etc.) according to a use etc. Further, the surface of the substrate may be subjected to a surface treatment such as a primer treatment, which will be described later, and a separate surface layer may be provided.

In addition, the shape of the substrate is not particularly limited including dimensions. For example, it may be a sheet shape, but may be a three-dimensional shape (curved shape, columnar shape, cylindrical shape, etc.), and may be a desired shape depending on the application or application target.

<< Structure: Film >>
The sealing member of the present invention has at least one of an allyl ether group, a vinyl ether group, and a (meth) acrylate group as a terminal functional group on a part of at least one surface of the substrate and a part of the opposite surface. It has the film | membrane which is a hardened | cured material of the composition containing a urethane prepolymer and the polythiol which has a thiol group. A specific method for forming a film (such as raw materials) will be described later.

Such a film is formed directly (in close contact) with a part of at least one surface of the substrate and a part of the opposite surface. In the seal member according to the present invention, when the seal member is used, a film is positioned at a part or all of the contact portion between the seal member and the member to be sealed when the member is pressed between the members to be sealed. It is assumed that. According to the sealing member of the present invention, when such a method of use (for example, a gasket or the like) is assumed, the follow-up adhesion between the film and the member to be sealed can be further improved by adopting the above-mentioned film. It makes it possible to improve the aqueous property. From such a viewpoint, an embodiment in which a film is provided on the entire surface of the substrate is also conceivable.

As described above, “at least a part of one surface of the substrate and at least a part of the opposite surface” as the place where the film is formed on the substrate is the contact between the sealing member and the member to be sealed according to the present invention. A part (or all) of the substrate as a place is assumed. Thus, for example, when the substrate is in the form of a sheet, the film is formed on a part of the surface and part of the back surface of the substrate. And part of the surface on the back side thereof (in the case of a columnar shape or the like, a part including a part on a certain busbar and a part including a part on a busbar located on the opposite side) In the case of a cylinder or the like (and for use in which the sheet is sandwiched from the inner side surface and the outer side surface of the cylinder), 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 adjusted as appropriate according to the application and the like, and is not particularly limited. For example, it may be 10 to 500 μm.

<< Physical properties >>
In addition, since the seal member is used in a compressed state in the gaps between the members, if the film of the seal member is compressed and there is little distortion after the compression is released, long-term water stopping properties can be ensured. It is assumed. For this reason, the compression set (%) is preferably 20% or less, and more preferably 15% or less. The compression set (%) can be measured based on JIS K 7312: 1996. Specifically, the compression set (%) can be measured according to the following conditions.
Test piece: Cylindrical film of t12.5 mm × φ29 mm Test conditions: After 22 hours at 70 ° C. with 25% compression, the compression is released and left at 23 ° C. for 30 minutes to cool compression set = {( t ₀ -t ₁ ) / (t ₀ -t ₂ )} × 100
t _0; thickness t 2 after the cooling of the _{_specimen;} the thickness of the spacer thickness t 1 before compression of the test piece

<< Usage >>
Since the sealing member of the present invention has the above-mentioned film that becomes an adhesive surface on both surfaces of the substrate, it can be applied without using a double-sided tape or the like, and adhesive residue or the like hardly occurs (has high reworkability). Also, because it has excellent sealing performance when placed in a narrow part such as a gasket, it is used not only for water stop but also for various applications such as dust prevention, heat insulation, sound insulation, vibration prevention, buffering and airtightness it can. More specifically, for example, it can be used as a dustproof material, a heat insulating material, a soundproof material, a vibration proof material, a shock absorbing material, a filler, and the like. In addition, it can be used regardless of the front and back (for example, it can be used for a plurality of sets of sealed parts that are symmetrical in the left-right direction (or up-and-down symmetry)), particularly in automobiles, motorbikes, railway vehicles, etc. It is suitable as a sealing material for a vehicle lamp (for a module component constituting a vehicle lamp and sealing a lamp and a casing).

By the way, the gasket for vehicle lamps is disposed between the lamp body and the vehicle in order to prevent water from entering. Double-sided tape was affixed to one side of the conventional gasket, and the double-sided tape was in close contact with the lamp glass. In addition, the gasket fabric on the side where the double-sided tape was not adhered was in close contact with the metal housing of the lamp body.
In addition, the lamps (vehicle lamps) are mounted on the left and right in the vehicle width direction, and the shape design is also symmetrical. Therefore, when only mounting the lamp gasket is considered, it is only necessary to have a double-sided tape only on the surface to be bonded to the lamp glass, as described above, and therefore the double-sided tape is attached only to one side of the lamp gasket.

Also, if double-sided tape is applied to both sides of the gasket, when repairing the lamp module due to failure, damage, etc. after mounting on the vehicle, the metal housing side will also be bonded with double-sided tape, so disassembling the module There was a problem that adhesive residue remained. Furthermore, not only when repairing, but also when assembling the vehicle, it is not always possible to perform the assembly work at once, and there is an opportunity to peel it off and re-attach it twice, and the double-sided tape also requires reworkability. It was.
However, considering the manufacturing process and man-hours of the lamp module, the gasket with the double-sided tape affixed on one side has the front and back surfaces of the gasket itself, and the right and left lamp gaskets must be managed separately. .

According to the present invention, by laminating an adhesive having a predetermined adhesive force on both surfaces of the gasket, it is not necessary to distinguish the gasket itself for the right lamp and the left lamp, and the labor of component management is facilitated. . Moreover, since it has a predetermined adhesive strength, it has excellent reworkability, and there is no adhesive residue on the metal housing during repair, improving workability during repair and assembly.

<<< Method for Manufacturing Seal Member >>>
The “method for producing a seal member” of the present invention comprises a raw material containing a urethane prepolymer having at least one of an allyl ether group, a vinyl ether group, and a (meth) acrylate group as a terminal functional group, and a polythiol having a thiol group. An adhesion step of attaching to a part of at least one surface of the substrate, which is an elastically deformable foam, and a part of the opposite surface, and an irradiation step of irradiating light to the raw material attached in the attachment step A sealing member is produced by a photopolymerization reaction. Next, an example of each raw material and a specific manufacturing process will be described.

<< Raw material >>
First, each raw material in a sealing member is explained in full detail. In addition, since it is as above-mentioned about a base | substrate, description is abbreviate | omitted.

<Film>
The film of the sealing member according to the present invention comprises a composition (mixture) comprising a urethane prepolymer having at least one of an allyl ether group, a vinyl ether group, and a (meth) acrylate group as a terminal functional group, and a polythiol having a thiol group. ) As a raw material. Each will be described in detail below.

A urethane prepolymer having at least one of an allyl ether group, a vinyl ether group, and a (meth) acrylate group as a terminal functional group includes an allyl ether group, a vinyl ether group, and a urethane prepolymer synthesized from a polyol and a polyisocyanate ( It is produced by adding a compound having at least one of a (meth) acrylate group. Normally, a urethane prepolymer having any one of an allyl ether group, a vinyl ether group, and a (meth) acrylate group as a terminal functional group is used. However, an allyl ether group, a vinyl ether group, a (meth) acrylate group, and It is also possible to use a urethane prepolymer in which a plurality or all of these are present as terminal functional groups (for example, mixing a plurality of types of urethane prepolymers).

In order to improve the followability of the film to the substrate, the urethane prepolymer preferably has a weight average molecular weight of 1000 to 30000. Furthermore, it is preferably 1500 to 25000. The weight average molecular weight of the urethane prepolymer is a theory derived from a molecular weight measured by a known method (for example, GPC method) or a weight average molecular weight of the raw material (known method, for example, by GPC method). The molecular weight may be used. The weight percentage of terminal functional groups (that is, allyl ether group, vinyl ether group and (meth) acrylate group) of the urethane prepolymer is preferably 0.5 to 35%, preferably 0.75 to 30%. More preferably, it is 0.9 to 25% or more. In addition, it is preferable that the weight percentage of the terminal functional group of the urethane prepolymer is calculated by a theoretical value (theoretical value based on manufacturing conditions such as raw materials) when adding the terminal functional group to the urethane prepolymer. It may be measured by a known method.

The “polyisocyanate” used for the synthesis of the urethane prepolymer is a compound having two or more isocyanate groups in one molecule, and may be any compound that is usually employed as a raw material for the urethane prepolymer. For example, aromatic isocyanate, aliphatic isocyanate, alicyclic isocyanate, etc. are mentioned. Examples of the aromatic isocyanate include tolylene diisocyanate (TDI), 4,4'-diphenylmethane diisocyanate (MDI), polymeric 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. What used together 1 type, or 2 or more types of these various polyisocyanates can be used as a raw material of the said urethane prepolymer.

Further, the “polyol” used for the synthesis of the urethane prepolymer is a compound having two or more hydroxyl groups in one molecule, and any compound that is usually employed as a raw material for the urethane prepolymer may be used. For example, a polyester polyol, a polyether polyol, etc. are mentioned. Some polyester polyols are obtained by a condensation reaction between a polyhydric alcohol and a polycarboxylic acid. Examples of the polyhydric alcohol include ethylene glycol, propylene glycol, butanediol, butylene glycol, glycerin, trimethylolpropane, and the like, 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, and isophthalic acid, and these can be used alone or in combination of two or more. Furthermore, the polyester polyol obtained by ring-opening condensation of caprolactone, methylvalerolactone, etc. is mentioned.

Examples of polyether polyols include addition polymerization of oxides such as ethylene oxide, propylene oxide, trimethylene oxide, and butylene oxide to polyhydric alcohols such as ethylene glycol, propylene glycol, diethylene glycol, glycerin, trimethylolpropane, and sorbitol. Can be mentioned. A combination of one or more of these various polyols can be used as a raw material for the urethane prepolymer.

In addition, it is preferable to use a catalyst in the synthesis of the urethane prepolymer. The catalyst is not particularly limited as long as it is normally employed as a raw material for the urethane prepolymer, and examples thereof include amine-based catalysts and organometallic catalysts. Examples of the amine catalyst include triethylenediamine, diethanolamine, dimethylaminomorpholine, N-ethylmorpholine and the like. Examples of the organometallic catalyst include star octoate, dibutyltin dilaurate, lead octenoate, potassium octylate and the like. A combination of one or more of these various catalysts can be used as the catalyst for the urethane prepolymer.

The compound having at least one of an allyl ether group, a vinyl ether group, and a (meth) acrylate group to be added to the synthesized urethane prepolymer may be any compound that can be added to the isocyanate group of the urethane prepolymer, Examples include allyl ether glycol, hydroxyethyl allyl ether, hydroxypropyl vinyl ether, hydroxybutyl vinyl ether, and hydroxyethyl (meth) acrylate. In order to increase the reaction activity, a monofunctional active hydrogen compound is preferable, and it is preferable that the double bond is in the vicinity of both ends of the polymer.

Examples of the polythiol that undergoes an enethiol reaction with the urethane prepolymer include esters of mercaptocarboxylic acid and polyhydric alcohol, aliphatic polythiols, and aromatic polythiols. Examples of the aliphatic polythiol and the aromatic polythiol include ethanedithiol, propanedithiol, hexamethylenedithiol, decamethylenedithiol, tolylene-2,4-dithiol, xylenedithiol and the like.

Further, in the ester of mercaptocarboxylic acid and polyhydric alcohol, examples of the mercaptocarboxylic acid include thioglycolic acid and mercaptopropionic acid, and examples of the polyhydric alcohol include ethylene glycol, propylene glycol, 1,4-butanediol, , 6-hexanediol, glycerin, trimethylolpropane, pentaerythritol, sorbitol and the like. Of these, esters of mercaptocarboxylic acids and polyhydric alcohols are preferred from the viewpoint of low odor. Specifically, for example, trimethylolpropane tris (3-mercaptopropionate), pentaerythritol tetrakis (3 -Mercaptopropionate), tetraethylene glycol bis (3-mercaptopropionate), dipentaerythritol hexa (3-mercaptopropionate). In addition, it is possible to use what used together 1 type, or 2 or more types of those various polythiols as a raw material of enethiol reaction with the said urethane prepolymer.

The above-mentioned urethane prepolymer having at least one of allyl ether group, vinyl ether group and (meth) acrylate group as a terminal functional group and polythiol are mixed and irradiated with light, whereby the surface of the substrate is subjected to an enethiol reaction. It is possible to form a film on at least a part of the film. Further, as the above-mentioned polythiol, a polythiol having an average functional group number of thiol groups of preferably more than 2, more preferably 2.5 to 6.0, can be used to form a highly water-stopping film. Is possible. This film preferably has an elongation measured based on JISK6400 of 70% or more, and more preferably 100% or more. The upper limit of the elongation of the film is not particularly limited, but is usually preferably 250%, particularly preferably 200%. Accordingly, the elongation is preferably from 70 to 250%, particularly preferably from 100 to 200%. When the elongation is 70% or more, the flexibility of the seal member is improved, or cracks and the like are prevented from occurring in the creep state, and in particular, water leakage from the interface between the seal member and the close contact surface is prevented. On the other hand, it is sufficient if the elongation is 250%, particularly 200%. By setting it to 250% or less, the film becomes moderately flexible and does not extend too much with a slight stress, so that it is difficult to leak water.

The amount of the thiol group possessed by the polythiol to be reacted with the urethane prepolymer having at least one of an allyl ether group, a vinyl ether group, and a (meth) acrylate group as a terminal functional group is the allyl ether group possessed by the urethane prepolymer. It is preferable that the ratio (ene / thiol ratio) of the total number of thiol groups of the polythiol to the total number of equivalents of the vinyl ether group and the (meth) acrylate group is 0.7 to 2.5. By setting the ene / thiol ratio within this range, it is possible to obtain a higher water-stopping property. As for the ene / thiol ratio, in the case of a urethane prepolymer in which a plurality or all of allyl ether groups, vinyl ether groups, and (meth) acrylate groups are present as terminal functional groups, thiol with respect to the total number of these equivalents. The ratio of the total number of equivalent groups is shown.

In addition, in order to effectively perform a photopolymerization reaction between at least one of an allyl ether group, a vinyl ether group, and a (meth) acrylate group added to the urethane prepolymer, and a thiol group, a photopolymerization initiator is added to the compounding raw material. It is possible to include. Examples of the photopolymerization initiator include acetophenone-based, benzophenone-based, and thioxanthone-based compounds.
Examples of the acetophenone series include 2,2-dimethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, 4- (1-t-butyldioxy-1-methylethyl) acetophenone, 2-methyl-1- [4- (Methylthio) phenyl] -2-morpholino-propan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1, diethoxyacetophenone, 2-hydroxy-2-methyl- 1-phenylpropan-1-one, benzyldimethyl ketal, 4- (2-hydroxyethoxy) phenyl- (2-hydroxy-2-propyl) ketone, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1 -[4- (1-Methylvinyl) phenyl] propanone oligomer And the like.

Examples of the benzophenone series include 4- (1-t-butyldioxy-1-methylethyl) benzophenone, 3,3 ′, 4,4′-tetrakis (t-butyldioxycarbonyl) benzophenone, and methyl o-benzoylbenzoate. 4-phenylbenzophenone, 4-benzoyl-4'-methyl-diphenyl sulfide, 3,3 ', 4,4'-tetra (t-butylperoxylcarbonyl) benzophenone, 2,4,6-trimethylbenzophenone, 4- And benzoyl-N, N-dimethyl-N- [2- (1-oxo-2-propenyloxy) ethyl] benzenemethananium bromide, (4-benzoylbenzyl) trimethylammonium chloride, and the like.
Examples of the thioxanthone series include 2,4-dimethylthioxanthone, 2,4-diisopropylthioxanthone, 2-chlorothioxanthone, 2-isopropylthioxanthone, 4-isopropylthioxanthone, 2,4-diethylthioxanthone, 2,4-dichloro Examples include thioxanthone, 1-chloro-4-propoxythioxanthone, 2- (3-dimethylamino-2-hydroxy) -3,4-dimethyl-9H-thioxanthone-9-one mesochloride.

The content of the photopolymerization initiator is preferably 0.01 to 5 parts by weight per 100 parts by weight of the urethane prepolymer, and more preferably 0.1 to 3 parts by weight. 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 accelerated, and the crosslinking density is high. It is possible to prevent the cross-linking structure from being excessively formed or the cross-linked structure from being formed unevenly.

As a raw material (composition) for film formation, in addition to the above, known additives and diluents may be included as appropriate, but the urethane prepolymer and the polythiol having the thiol group are raw materials (composition). More specifically, the total amount of these components is preferably 90 parts by weight, more preferably 95 parts by weight with respect to the raw material (composition).

<< Manufacturing process >>
As a manufacturing process of the sealing member according to the present invention, an adhesion step of attaching a film forming raw material to a substrate, an irradiation step of irradiating the raw material attached in the attachment step with light, and curing the raw material by a photopolymerization reaction, Is not limited at all as long as it includes (for example, a cleaning step, a drying step, a processing step (molding step), and the like may be included). Hereinafter, an example of the manufacturing method of the sealing member concerning the present invention is explained. In addition, about a base | substrate, since it can manufacture according to a well-known manufacturing method (a foaming method or a hardening method), description is abbreviate | omitted.

A film forming raw material (mixed raw material) in which the urethane prepolymer having at least one of the above-mentioned allyl ether group, vinyl ether group, and (meth) acrylate group as a terminal functional group and polythiol is mixed is excellent in permeability. It is applied to a film or the like with a predetermined film thickness. Next, the surface of the elastically deformable substrate is pressure-bonded onto the applied mixed raw material (attachment step). At this time, the liquid mixed raw material is appropriately mixed 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, whereby the mixed raw material is cured and a film is formed (irradiation step). As a result, the raw material is cured while the liquid raw material and the surface of the base body are appropriately blended, thereby improving the adhesion between the base body and the film. Furthermore, 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 performed similarly. A seal member having a film is formed on both surfaces (front surface and back surface) of the substrate. In addition, the method of forming a film on both surfaces of the substrate is not limited to this, and the mixed raw material is attached to at least a part of the surface of the substrate and at least a part of the back surface, and the mixed raw material is cured at once. Also good.

In the case where a substrate of a predetermined material, specifically, for example, a substrate made of ethylene propylene diene rubber (EPDM) is employed as the elastically deformable substrate, a primer is provided on the adhesion surface of the substrate to the mixed raw material. By performing the treatment (primer step), a modified layer (surface layer) is formed on the surface of the substrate, and the adhesion between the substrate and the film can be ensured. Examples of the primer treatment include blast treatment, chemical treatment, degreasing, flame treatment, oxidation treatment, steam treatment, corona discharge treatment, ultraviolet irradiation treatment, plasma treatment, ion treatment and the like. The primer treatment may be a lamination of an undercoat layer by a so-called undercoat in a narrow sense with a so-called primer resin. Specifically, an undercoat layer of a polyolefin resin modified with an unsaturated polyvalent carboxylic acid compound and a (meth) acrylic compound is preferable. In addition, among the above plasma treatments, atmospheric pressure plasma treatment is preferable in terms of improving adhesion.

It irradiation amount of light for curing the mixed material (e.g., ultraviolet light) is not limited as long as curable a mixed raw material, for example, 600 ~ 1800mJ ^/ cm 2 (365nm integrated quantity of light) Is preferred. Further, the irradiation time is not particularly limited, and can be appropriately changed according to the mixed raw material to be used and the light irradiation amount.

In addition, 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, a die coater is preferably used because the viscosity of the viscous fluid can be adjusted by adjusting the temperature of the viscous fluid during application.

Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to this embodiment, and can be implemented in various modes with various modifications and improvements based on the knowledge of those skilled in the art.

<< Raw material and production of seal member >>
From the raw materials having the formulations shown in Tables 2 to 9, the seal member films of Examples 1 to 15 and the seal member films of Comparative Examples 1 to 3 were produced. Below, the detail of each raw material is shown.

<Coating composition (mixture)>
First, each “prepolymer” shown in Tables 2 to 9 was obtained by reacting raw materials having the composition (weight ratio) shown in Table 1 according to the following method.

First, the amount of polyisocyanate shown in Table 1 was put into a 1-liter separable flask, and the amount of polyol shown in Table 1 was added with stirring while flowing nitrogen. After confirming that the contents were uniform, a catalyst (dibutyltin dilaurate (DBTDL) 0.3 g) was added. Then, the temperature was slowly raised so that the temperature of the contents became 80 to 90 ° C. over 1 hour. Two hours after raising the temperature to the target temperature, the isocyanate group content was measured according to a method based on JIS Z1603-1: 2007 (polyurethane raw material aromatic isocyanate test method). And in prepolymer A and C, it confirmed that the isocyanate group content rate was in the range of 4.0 to 5.0%. In Prepolymer B, it was confirmed that the isocyanate group content was in the range of 2.0 to 3.0%. In addition, in the prepolymers D and H, it was confirmed that the isocyanate group content was in the range of 0.5 to 1.0%. In Prepolymer E, it was confirmed that the isocyanate group content was in the range of 6.0 to 7.0%. In addition, it was confirmed that the prepolymer F had an isocyanate group content in the range of 0.5 to 1.0%. In Prepolymer G, it was confirmed that the isocyanate group content was in the range of 14.0 to 15.0%. And when isocyanate group content rate was not in the range according to each prepolymer, reaction time was extended.

After confirming that the isocyanate group content is within the range corresponding to each prepolymer, at least one of vinyl ether, allyl ether, and (meth) acrylate was slowly dropped in the amount shown in Table 1, and 2 The reaction was performed for a time. After 2 hours, the isocyanate group content was measured again according to the above method, and it was confirmed that the isocyanate group content was 0.5% or less. Each “prepolymer” shown in Table 1 was obtained on condition that the isocyanate group content was 0.5% or less.

Polyol a: Polypropylene glycol (PPG), trade name: Actol D2000 (Mw: 2000), manufactured by Mitsui Chemicals, Inc. Polyol b: Polypropylene glycol (PPG), trade name: Actol D1000 (Mw: 1000), Polyol c: Polypropylene glycol (PPG), manufactured by Mitsui Chemicals, Inc., trade name: Sannix PP-200 (Mw: 200), Polyol d: Polypropylene glycol (PPG), manufactured by Sanyo Chemical Co., Ltd., trade name: Preminol S4013 (Mw: 12000), manufactured by Asahi Glass Co., Ltd., polyol e; Polypropylene glycol (PPG), trade name: Preminol S4318 (Mw: 18000), manufactured by Asahi Glass Co., Ltd., polyisocyanate; Tolylene diisocyanate (TDI), product Name: Leplanay T-80 (Mw: 174.2), BASF made vinyl ether; hydroxybutyl vinyl ether (Mw: 116.2), Nippon Carbide Corp. made allyl ether; hydroxyethyl allyl ether (Mw: 102.1), Japan Emulsifier Co., Ltd. (meth) acrylate; 2-hydroxyethyl methacrylate (Mw: 130.1), manufactured by Nippon Shokubai Co., Ltd.

Further, the total number of equivalents of at least one of allyl ether group, vinyl ether group and (meth) acrylate group contained in 100 parts by weight of each “prepolymer” obtained as described above was calculated. Then, the equivalent number of thiol groups contained in the curing agent (thiol) necessary as a raw material was calculated by multiplying the calculated equivalent number by the enethiol ratio (equivalent ratio) shown in Tables 2 to 9. Each thiol having the calculated number of moles and 100 parts by weight of the prepolymer were weighed and heated to 80 ° C., and then mixed and stirred. Tables 2 to 9 show specific blending amounts (parts by weight) of each thiol with respect to 100 parts by weight of each prepolymer.

-Thiol A: 2 functional groups, butanediol bisthiopropionate, trade name: BDTP (Mw: 266.4), manufactured by Sakai Chemical Co., Ltd.-Thiol B: 3 functional groups, trimethylolpropane tris (3-mercapto Propionate), trade name: TMMP (Mw: 398.5), SC Organic Chemical Co., Ltd., Thiol C; functional group number 4, pentaerythritol tetrakis (3-mercaptopropionate), trade name: PMP (Mw : 488.6), manufactured by SC Organic Chemical Co., Ltd., Thiol D; functional group number 6, dipentaerythritol hexakis (3-mercaptopropionate), trade name: DPMP (Mw: 783.0), SC organic chemistry Made by

The average number of functional groups of thiol groups that react with each urethane prepolymer is shown in the column “Average number of functional groups” in Tables 2 to 9. Further, the ratio of the total number of equivalents of all thiol groups to the total number of equivalents of vinyl ether groups, allyl ether groups and (meth) acrylate groups of each urethane prepolymer is shown in the column “En-thiol ratio” in Tables 2 to 9. Show. In the table, the urethane polymers A to H have the same molecular weight in the case of the same type, and the thiols A to D have the same number of functional groups in the same type and are therefore omitted. There is a case.

<Adhesion process and irradiation process>
Then, the raw materials mixed in the mixing ratios shown in Tables 2 to 9, that is, the mixed prepolymer and thiol, were applied on a release film having good permeability so as to have a film thickness of 50 μm. Next, a natural rubber-based foam (manufactured by Inoac, N-148) or an EPDM-based foam (manufactured by Inoac, product number: E-4388) as a base was pressure-bonded onto the applied mixed raw material. The contact surface with the raw material of the EPDM foam was subjected to primer treatment. Specifically, atmospheric pressure plasma is irradiated onto the substrate under the conditions of a scanning speed of 200 mm / s, an irradiation distance of 10 mm, and an irradiation frequency of 2 times by an Openair (registered trademark) plasma system component (manufactured by Nippon Plasma Treat Co., Ltd.). did.

The mixed raw material to which the foam was pressure-bonded was irradiated with ultraviolet rays from below the release film. Thereby, the applied mixed raw material was cured, and a member having a film formed on one surface was obtained. Next, a coating film was formed on the surface of the substrate opposite to the surface on which the coating film was formed by the same method to form seal members of Examples 1 to 15. Incidentally, the irradiation amount of ultraviolet rays when curing the mixed raw material was set to 600 mJ / cm ² (365 nm integrated light amount). Each of Examples 1 to 15 includes two types of embodiments, one in which the base is a natural rubber-based foam and one in which the base is an EPDM-based foam. The difference by each aspect was not confirmed in evaluation mentioned later. Tables 2 to 8 show the results of each example in a single column, because the results were the same in the two modes.

As the sealing member of Comparative Example 1, a member having a film formed only on one surface was adopted. Further, as a sealing member of Comparative Example 2, a natural rubber-based foamed body (manufactured by INOAC, N-148, thickness 5 mm) having no film formed thereon was employed. Furthermore, as the seal member of Comparative Example 3, a double-sided tape (Nitto Denko No. 500) was used on both sides of a natural rubber foam (Inoac, N-148, thickness 5 mm) as a base. did.

The sealing performance of the sealing member manufactured by the above method was evaluated using the instrument 10 shown in FIGS. FIG. 1 is a side view of the instrument 10, and FIG. 2 is a plan view showing the instrument 10 from a viewpoint from above. The instrument 10 includes a base 20, a steel plate 22, a spacer 24, an acrylic plate 26, and an adapter 28. The steel plate 22 is obtained by coating a polyester resin and a melamine resin paint (Neo-Amilak 6000 made by Kansai Paint) on the surface of an iron plate having a thickness of 1 mm, and is placed on the upper surface of the base 20. Spacers 24 having a thickness of 2.5 mm are placed at the four corners of the upper surface of the steel plate 22. Then, the test sample 30 of the seal member is placed on the upper surface of the steel plate 22, and the acrylic plate 26 is placed on the upper surface of the test sample 30.

As the test sample 30, an annular seal member having an outer diameter of 60 mm, an inner diameter of 40 mm, and a thickness of 5 mm was used. Specifically, first, a seal member having a thickness of 5 mm is manufactured by the above-described method, and then the seal member is punched into an annular shape having an outer diameter of 60 mm and an inner diameter of 40 mm by a punching die. Using. The test sample 30 was placed on the steel plate 22 with the coating of the test sample 30 in close contact with the steel plate 22 side and the coating on the opposite side facing upward (the seal of Comparative Example 1). Regarding the member, the surface on which the film was formed was placed on the lower side, and the sealing members of Comparative Example 2 and Comparative Example 3 were placed regardless of the upper and lower sides). Then, the acrylic plate 26 was placed on the test sample 30 and sandwiched between the steel plate 22 and the acrylic plate 26, whereby the test sample 30 was compressed to the thickness (2.5 mm) of the spacer 24. That is, the test sample 30 was compressed to 50% (2.5 mm / 5 mm). A through hole 32 is formed in the acrylic plate 26 so as to penetrate the annular shape of the test sample 30 compressed by the steel plate 22 and the acrylic plate 26, and the adapter 28 is connected to the through hole 32. Has been. Then, in a state where the test sample 30 is compressed by the steel plate 22 and the acrylic plate 26, (1) within 10 minutes after the sample setting as the initial test, and (2) a constant temperature and humidity chamber at 23 ° C. as the time test. Then, after leaving the sample set for 65 hours, the evaluation was started.

Then, distilled water was supplied to the inside of the annular shape of the test sample 30 via the adapter 28, and the inside of the annular shape of the test sample 30 was filled with distilled water. Then, 5 KPa of air is supplied to the inside of the test sample 30 filled with distilled water via the adapter 28 and maintained in that state for 5 minutes, and then water leakage to the outside of the test sample 30 is prevented. The presence or absence was confirmed visually. If there is no water leakage to the outside of the test sample 30, 5 kPa air is further supplied to the inside of the test sample 30 via the adapter 28 and maintained in that state for 5 minutes. The presence or absence of water leakage to the outside of the sample 30 was confirmed visually. At this time, when there was no water leak to the outside of the test sample 30, the supply of 5 KPa air and the confirmation of the water leak after being maintained in that state for 5 minutes were repeated. In this way, the presence or absence of water leakage to the outside of the test sample 30 is confirmed, and when there is no water leakage when 30 KPa air is supplied to the inside of the test sample 30, it is used as the test sample 30. The obtained sealing member was judged to have particularly good water-stopping properties.

<Evaluation of seal member: water-stop>
With respect to the seal members of Examples 1 to 15 and the seal members of Comparative Examples 1 to 3, the above-described instrument 10 was used, and (1) the initial test and (2) the time-lapse test were evaluated. In this evaluation, when there was no water leak when air of 30 KPa was supplied, it was evaluated as “◯”, and when water leak occurred at the stage when air of more than 5 kPa and less than 30 kPa was supplied, When the water leakage occurred at the stage where air of 5 kPa or less was supplied (stage before the first 5 minutes), it was evaluated as “x”. The evaluation results are shown in the “Water-stop evaluation” column of Tables 2-9.

<Evaluation of seal member: Reworkability>
After each (1) initial test and (2) aging test, the presence or absence of deposits on the acrylic plate side and the coated plate side was visually confirmed when the sample was taken out from the evaluation jig. When the deposit was not confirmed, it was marked as ◯, and when it was confirmed, it was marked as x.

From the above results, a urethane prepolymer having at least one of an allyl ether group, a vinyl ether group, and a (meth) acrylate group as a terminal functional group and a polythiol having a thiol group are used on the surface of the foam (substrate). It is understood that it is possible to increase the water-stopping property and reworkability of the seal member by forming a film by the enethiol reaction with the raw material and forming such a film on both surfaces of the substrate.

In each example, when the compression set (%) was measured based on the method based on JIS K 7312: 1996 for only the film component, it was confirmed that all the compression set was 15% or less. It was done.

Although the invention has been described in detail with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.
The present application is based on a Japanese patent application (Japanese Patent Application No. 2016-216916) filed on November 7, 2016 and a Japanese patent application (Japanese Patent Application No. 2017-45344) filed on March 9, 2017. Which is incorporated by reference in its entirety. Also, all references cited herein are incorporated as a whole.

Claims

A substrate that is an elastically deformable foam;
Using a composition comprising a urethane prepolymer having at least one of an allyl ether group, a vinyl ether group, and a (meth) acrylate group as a terminal functional group, and a polythiol having a thiol group, at least one surface of the substrate is used. A seal member provided with a coating formed on at least a part of a part and the opposite side.
2. The sealing member according to claim 1, wherein the average number of functional groups of the thiol group of the polythiol is 2.5 to 6.0.
The ratio of the total equivalent number of thiol groups of the polythiol to the total equivalent number of allyl ether groups, vinyl ether groups and (meth) acrylate groups of the urethane prepolymer is 0.7 to 2.5. The sealing member according to claim 1 or 2.
The seal member according to any one of claims 1 to 3, wherein a weight percentage of the terminal functional group in the urethane prepolymer is 0.5 to 35%.
The sealing member according to any one of claims 1 to 4, wherein the base is a foam made of closed cells.
The seal member according to any one of claims 1 to 5, wherein the seal member is used for a vehicle lamp.
7. The foam according to claim 1, wherein the substrate is an ethylene-α-olefin-nonconjugated diene terpolymer foam made of closed cells and having a surface layer formed by plasma treatment. The sealing member as described in any one.
One of the base | substrates which are the foams which can be elastically deformed from the raw material containing the urethane prepolymer which has at least 1 of an allyl ether group, a vinyl ether group, and a (meth) acrylate group as a terminal functional group, and the polythiol which has a thiol group Attaching to at least part of the surface and at least part of the opposite surface;
An irradiation step of irradiating the raw material attached in the attachment step with light.
A primer step of forming a surface layer by plasma treatment on at least a part of one surface of the substrate which is the elastically deformable foam and at least a part of the opposite surface is included before the attaching step. Item 9. A method for producing a sealing member according to Item 8.