JP2018150393A - Seal member and method for producing seal member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a seal member which has sufficient adhesion between a surface film becoming an adhesive surface provided on a surface of a foam and a foam, can follow and come in contact with a surface of a sealed member, has high cut-off performance, and is excellent in reworkability.SOLUTION: A seal member has a film formed using a composition containing an urethane prepolymer and polythiol having a thiol group provided on at least a part of one surface of a base being a foam and at least a part on an opposite surface thereto.SELECTED DRAWING: None

Description

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

JP 2001-35216 A

  However, when the conventional gasket as described above does not use a double-sided tape at the time of assembling, it may be difficult to follow and adhere to the automobile body due to the sticking (stress relaxation) of the foamed rubber after assembling. For this reason, dust and water may infiltrate due to vibration and the like, and it has been difficult to maintain a high water-stopping property.

  On the other hand, conventional gaskets such as those described above have problems with reworkability when double-sided tape is used during assembly, and it is difficult to rework when misalignment occurs during bonding. It is possible.

  This invention is made | formed in view of the said point, Comprising: It aims at provision of the sealing member which can be followed closely_contact | adhered to the unevenness | corrugation of the surface of a to-be-sealed member, has high water-stopping property, and is excellent in rework property.

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)
The average functional group number of the thiol group of the polythiol is 2.5 to 6.0. The sealing member according to the invention (1), wherein the number of functional groups is 2.5 to 6.0.
The present invention (3)
The ratio of the total equivalent number of the thiol group possessed by the polythiol to the total equivalent number of the allyl ether group, vinyl ether group and (meth) acrylate group possessed by 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 sealing member according to any one of the inventions (1) to (5), wherein the sealing member is for a vehicle lamp.
The present invention (7)
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.
Here, in the invention (7),
It is preferable that the average functional group number 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 preferably 0.7 to 2.5. And
The urethane prepolymer preferably has a weight average molecular weight of 1000 to 30000,
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.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the sealing member which can follow and adhere to the unevenness | corrugation of the surface of a to-be-sealed member, has high water-stopping property, and is excellent in rework property.

  Furthermore, according to the sealing member of the present invention, since it has a structure having a surface film serving as an adhesive surface on both surfaces of the foam, it can be used as a dual purpose even when the member to be sealed has left and right (or top and bottom). Yes, 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 the “seal member manufacturing method” according to the present invention will be described, but the present invention is not limited thereto.

<<< 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. 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 particularly preferably a rubber sponge or polyolefin foam made of closed cell 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. The surface of the substrate may be subjected to a surface treatment such as a primer treatment described later.

  The shape of the substrate is not particularly limited including dimensions and the like. 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 coating is formed directly (in close contact) with a part of at least one surface and a part of the opposite surface of the substrate. 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, but may be, for example, 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 condition: After 22 hours at 70 ° C. in a compressed state of 25%, the compression is released and left to stand at 23 ° C. for 30 minutes. Cooling compression set = {( t ₀ −t ₁ ) / (t ₀ −t ₂ )} × 100
t ₀ ; Thickness before compression of test piece t ₁ ; Thickness after cooling of test piece t ₂ ; Thickness of spacer

<< 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).

<<< Seal Member Manufacturing Method >>>
The “seal member manufacturing method” of the present invention includes 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 This is a method for producing a sealing member 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. In general, 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, but the allyl ether group, the vinyl ether group, and the (meth) acrylate group It is also possible to use a urethane prepolymer in which a plurality of or all of them 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 preferable that it is 1500-25000. 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. Moreover, it is preferable that the weight percentage of the terminal functional group (namely, allyl ether group, vinyl ether group, and (meth) acrylate group) of the said urethane prepolymer is 0.5 to 35%, Preferably it is 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.

  The “polyol” used for the synthesis of the urethane prepolymer is a compound having two or more hydroxyl groups in one molecule, and may be any compound that is usually employed as a raw material for the urethane prepolymer. 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.

  Moreover, it is preferable to use a catalyst in the synthesis | combination of the said 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 a raw material 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 a polyhydric alcohol, aliphatic polythiols, and aromatic polythiols. Examples of the aliphatic polythiol and aromatic polythiol include ethanedithiol, propanedithiol, hexamethylenedithiol, decamethylenedithiol, tolylene-2,4-dithiol, xylenedithiol and the like.

  In the ester of mercaptocarboxylic acid and polyhydric alcohol, examples of mercaptocarboxylic acid include thioglycolic acid and mercaptopropionic acid, and examples of polyhydric alcohol include ethylene glycol, propylene glycol, 1,4-butanediol, , 6-hexanediol, glycerin, trimethylolpropane, pentaerythritol, sorbitol and the like. Among these, an ester of mercaptocarboxylic acid and a polyhydric alcohol is preferable in terms 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 polythiol described above, a thiol group having an average functional group number of preferably more than 2, more preferably 2.5 to 6.0, 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 70 to 250%, and particularly preferably 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 that is 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 and vinyl ether group of the urethane prepolymer. It is preferable that the ratio (ene / thiol ratio) of the total number of equivalents of all thiol groups to the total number of equivalents of (meth) acrylate groups 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. 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, the ene / thiol ratio is the total of these total equivalent numbers. The ratio of the total number of equivalents of thiol 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. As the acetophenone series, for example, 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- Examples include 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. The method for 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. It is 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, it is 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, steam treatment, corona discharge treatment, ultraviolet irradiation treatment, plasma treatment, ion treatment and the like.

Moreover, the irradiation amount of light (for example, ultraviolet rays) at the time of curing the mixed raw material is not limited as long as the mixed raw material can be cured, but is, for example, 600 to 1800 mJ / cm ² (365 nm integrated light amount). 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.

  Moreover, when apply | coating a mixed raw material to a film, it is preferable to use coating apparatuses, such as a comma coater, a die coater, and 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.

  The following examples illustrate the present invention more specifically. 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 >>
The film | membrane of the sealing member of Examples 1-15 and the film | membrane of the sealing member of Comparative Examples 1-3 were manufactured from the raw material of the mixing | blending shown in Tables 2-9. Below, the detail of each raw material is shown.

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

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

  After confirming that the isocyanate group content is within the range corresponding to each prepolymer, at least one of vinyl ether, (meth) acrylate and allyl ether was slowly dropped in the amount shown in Table 1 for 2 hours. Let the reaction take place. After 2 hours, the isocyanate group content is measured again according to the above method, and it is confirmed that the isocyanate group content is 0.5% or less. Each “prepolymer” shown in Table 1 is obtained on condition that the isocyanate group content is 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 manufactured by Mitsui Chemicals, Inc .; Polypropylene glycol (PPG), trade name: Sannix PP-200 (Mw: 200), manufactured by Sanyo Chemical Co., Ltd. • Polyol d; Polypropylene glycol (PPG), 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; TDI, trade name: Rupranate T- 80 (Mw: 174.2 BASF, vinyl ether; hydroxybutyl vinyl ether (Mw: 116.2), Nippon Carbide Corporation, allyl ether; hydroxyethyl allyl ether (Mw: 102.1), Nippon 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 is calculated. And the equivalent number of the thiol group contained in the hardening | curing agent (thiol) required as a raw material is calculated by multiplying the calculated equivalent number by the enethiol ratio (equivalent ratio) shown in Tables 2-9. Each thiol having the calculated number of moles and 100 parts by weight of the prepolymer are weighed, heated to 80 ° C., and then mixed and stirred. In addition, in Tables 2-9, the specific compounding quantity (weight part) of each thiol with respect to 100 weight part of each prepolymer is shown.

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

  In addition, the average functional group number of the thiol group with which each urethane prepolymer reacts is shown in the column of "Average functional group number" of Tables 2-9. Also, the ratio of the total number of equivalents of all thiol groups to the total number of equivalents of vinyl ether group, allyl ether group and (meth) acrylate group of each urethane prepolymer is shown in the column of “En / thiol ratio” in Tables 2-9. 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, so the description is omitted. There is a case.

<Adhesion process and irradiation process>
And the raw material mixed by the compounding ratio shown to Tables 2-9, ie, the mixed prepolymer, and thiol is apply | coated so that a film thickness may be set to 50 micrometers on a release film with favorable permeability | transmittance. Next, a natural rubber-based foam (manufactured by INOAC, N-148, thickness 5 mm) as a base is pressure-bonded onto the applied mixed raw material. And the ultraviolet-ray is irradiated to the mixed raw material by which the foam was crimped | bonded from the downward direction of a 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 the mixed raw material is cured is set to 600 mJ / cm ² (365 nm integrated light amount).

  In addition, as the sealing member of Comparative Example 1, a member in which a film is formed only on one surface is adopted. In addition, as a sealing member of Comparative Example 2, a natural rubber foam (made by INOAC, N-148, thickness 5 mm) having no film is employed. Further, as the sealing member of Comparative Example 3, a double-sided tape (Nitto Denko No. 500) is used on both sides of a natural rubber foam (made by INOAC, N-148, thickness 5 mm) as a base. doing.

  With respect to the sealing member manufactured by the above method, the water-stopping property was evaluated using the instrument 10 shown in FIGS. 1 and 2. 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 is used. Specifically, first, a seal member having a thickness of 5 mm is manufactured by the above-described method, and the seal member is punched into an annular shape having an outer diameter of 60 mm and an inner diameter of 40 mm by using a punching die. The test sample 30 is placed on the steel plate 22 in a state where the coating of the test sample 30 is in close contact with the steel plate 22 and the coating on the opposite side faces 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 is placed on the test sample 30, and the steel plate 22 and the acrylic plate 26 are sandwiched so that the test sample 30 is compressed to the thickness of the spacer 24 (2.5 mm). That is, the test sample 30 is 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 is started.

  Thereafter, distilled water is supplied into the annular shape of the test sample 30 via the adapter 28, and the annular shape of the test sample 30 is 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 is 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 is confirmed visually. At this time, when there is 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 are 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 seal member thus obtained is 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 30 KPa air was supplied, it was evaluated as “◯”, and when there was no water leak at the stage when air of more than 5 kPa and 30 kPa or less 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 column of “Water stop evaluation” in Tables 2-9.

<Evaluation of seal member: Reworkability>
(1) After each water-stopping evaluation in the initial test and (2) aging test, the presence or absence of deposits on the acrylic plate side and the coated plate side is visually confirmed when the sample is taken out from the evaluation jig. If the deposit cannot be confirmed, mark “Yes”. If confirmed, mark “No”.

  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.

Claims (7)

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 the thiol group possessed by the polythiol to the total equivalent number of the allyl ether group, vinyl ether group and (meth) acrylate group possessed by the urethane prepolymer is 0.7 to 2.5. The sealing member according to claim 1 or 2.   The weight percentage of the said terminal functional group in the said urethane prepolymer is 0.5 to 35%, The sealing member as described in any one of Claim 1 thru | or 3 characterized by the above-mentioned.   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. 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.

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