JP7315832B2 - Polyurethane adhesive composition - Google Patents

Description

The present invention relates to polyurethane adhesive compositions.

2. Description of the Related Art In recent years, there is a system that uses IoT (Internet of Things) to monitor information (for example, air pressure, etc.) of tires mounted on automobiles.

In the above system, in order to monitor the information of the tire as described above, the tire usually has an electronic device or a case for accommodating the electronic device (hereinafter referred to as "electronic device etc.") inside or outside the tire. However, in that case, it is necessary to fix the electronic device and the like to the tire with, for example, an adhesive layer.

Conventionally, there is a method of vulcanizing an adhesive layer together with an unvulcanized tire in advance, for example, in order to fix the electronic device or the like to a tire (for example, Patent Document 1).
WO 2005/010002 relates to a tire ready to receive elements, e.g. electronic elements, fixed to the inner and/or outer surface of the tire, comprising a receiving area, an adhesive layer arranged on said receiving area, and said adhesive A tire comprising an inner surface and/or an outer surface having a protective film disposed thereon, wherein the composition of said adhesive layer has a molar content of diene units greater than 10% relative to all elastomer block units Tires and the like are described which are based on a block thermoplastic elastomer (TPE) comprising a diene elastomer block having a
In Patent Document 1, the adhesive layer is vulcanized with the unvulcanized tire blank ([0101]-[0105], etc.).

Japanese Patent Publication No. 2018-501366

However, as described above, when an adhesive layer is partially arranged in an unvulcanized tire (or tire blank) and vulcanized, the positions where electronic devices and the like are attached can be freely determined in the tire after vulcanization. Since it cannot be set, it was considered to lack versatility.
In addition, it has been considered that placing the adhesive over a wide portion or the entirety of the inside or outside of the tire in order to freely set the mounting position of the electronic device or the like on the tire lacks productivity.
Therefore, an object of the present invention is to provide an adhesive composition that can be applied to vulcanized rubber to bond the vulcanized rubber.

As a result of intensive research to solve the above problems, the present inventors have found a urethane-based adhesive composition containing a polyisocyanate compound and a polyester having a glass transition temperature within a specific range and which may be urethane-modified. The inventors have found that vulcanized rubber can be adhered by applying to vulcanized rubber, resulting in the present invention.
The present invention is based on the above knowledge and the like, and specifically solves the above problems with the following configuration.

[1] a polyisocyanate compound;
It contains a polyester that has a glass transition temperature of -25 to 0 ° C. and may be urethane-modified,
A polyurethane adhesive composition applied to vulcanized rubber.
[2] The polyurethane-based adhesive composition according to [1], wherein the polyisocyanate compound is liquid at room temperature.
[3] the polyester further has a hydroxyl group,
The polyurethane adhesive composition according to [1] or [2], wherein the molar ratio (NCO/OH) of the isocyanate groups of the polyisocyanate compound to the hydroxyl groups of the polyester is 5.0 to 15.0. thing.
[4] The polyurethane adhesive composition according to any one of [1] to [3], which further contains a filler.
[5] The polyurethane-based adhesive composition according to [4], wherein the filler is clay.
[6] The polyurethane-based adhesive composition according to [4] or [5], wherein the content of the filler is 10 to 70% by mass relative to the total amount of the polyurethane-based adhesive composition.
[7] The polyurethane adhesive composition according to any one of [1] to [6], which further contains a plasticizer.
[8] The polyurethane adhesive composition according to [7], wherein the plasticizer has an SP value of 20 (MPa) ^1/2 or more.
[9] The polyurethane adhesive composition according to [7] or [8], wherein the plasticizer has a molecular weight of 1,000 or less.
[10] The polyurethane adhesive composition according to any one of [7] to [9], wherein the content of the plasticizer is 1 to 20% by mass with respect to the total amount of the polyurethane adhesive composition. .

The urethane-based adhesive composition of the present invention can be applied to vulcanized rubber to bond the vulcanized rubber.

The present invention will be described in detail below.
In this specification, the numerical range represented by "-" means a range including the numerical values before and after "-" as lower and upper limits.
In this specification, unless otherwise specified, each component can be used singly or in combination of two or more substances corresponding to the component. When the component contains two or more substances, the content of the component means the total content of the two or more substances.

[Urethane adhesive composition]
The urethane-based adhesive composition of the present invention (the composition of the present invention) is
a polyisocyanate compound;
It contains a polyester that has a glass transition temperature of -25 to 0 ° C. and may be urethane-modified,
It is a polyurethane-based adhesive composition that is applied to vulcanized rubber.

Since the composition of the present invention has such a constitution, it is believed that the desired effect can be obtained. Although the reason is not clear, by applying a composition containing a polyisocyanate compound and a polyester having a glass transition temperature within a specific range and optionally urethane-modified to the vulcanized rubber, the above-mentioned The inventors have found that the adhesion between the composition and the vulcanized rubber is excellent.
The above-mentioned excellent adhesiveness with vulcanized rubber is due to the fact that the glass transition temperature of the polyester is within a specific range, so that flexibility is imparted to the resulting adhesive. guess.
Each component contained in the composition of the present invention will be described in detail below.

<Polyisocyanate compound>
The polyisocyanate compound contained in the composition of the present invention is not particularly limited as long as it has two or more isocyanate groups in its molecule.
Examples of polyisocyanate compounds include tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), polymeric MDI, 1,4-phenylene diisocyanate, polymethylene polyphenylene polyisocyanate, xylylene diisocyanate (XDI), tetramethylxylylene diisocyanate ( TMXDI), tolidine diisocyanate (TODI), 1,5-naphthalenediisocyanate (NDI), aromatic polyisocyanate compounds such as triphenylmethane triisocyanate;
Hexamethylene diisocyanate (HDI), trimethylhexamethylene diisocyanate (TMHDI), lysine diisocyanate, norbornane diisocyanate (NBDI), transcyclohexane-1,4-diisocyanate, isophorone diisocyanate (IPDI), bis(isocyanatomethyl)cyclohexane (H ₆ XDI) aliphatic (where aliphatic is a concept including linear, branched and cycloaliphatic) polyisocyanates such as , dicyclohexylmethane diisocyanate (H ₁₂ MDI);
These carbodiimide-modified polyisocyanates are included.

Among these, the polyisocyanate compound is preferably an aromatic polyisocyanate, more preferably MDI and/or polymeric MDI, because of its excellent adhesiveness to vulcanized rubber and excellent curability.
Polymeric MDI is polymethylene polyphenyl polyisocyanate. Polymeric MDI may be a mixture of polymethylene polyphenyl polyisocyanates with different degrees of polymerization.
Polymeric MDI may contain MDI in addition to polymethylene polyphenyl polyisocyanate.

The polyisocyanate compound is preferably liquefied at room temperature (23° C.) from the standpoint of better adhesion to vulcanized rubber.
Examples of polyisocyanate compounds that are liquid at room temperature include polymeric MDI.

<Polyester>
The polyester contained in the composition of the present invention is a polyester polymer that has a glass transition temperature of -25 to 0°C and may be urethane-modified.
In this specification, the above polyester may be referred to as "specific polyester". The specific polyester has a glass transition temperature of −25 to 0° C. and is urethane-modified (a urethane-modified polyester described later), and/or has a glass transition temperature of −25 to 0° C. and is urethane-modified. Contains untreated polyester.

<Glass transition temperature>
In the present invention, the glass transition temperature of the specific polyester is -25 to 0°C.
Since the glass transition temperature is within the specific range, the composition of the present invention has excellent adhesion to vulcanized rubber.

The above glass transition temperature is preferably -15 to 0°C for the reason that the adhesion to vulcanized rubber is superior.
In the present invention, the glass transition temperature can be measured with a differential scanning calorimeter. For example, the above measurement is performed at a rate of temperature increase of 20° C./min, and the glass transition temperature can be calculated from the results by the midpoint method.

(functional group)
The specific polyester can further have at least one functional group selected from the group consisting of a hydroxyl group, a carboxyl group (--COOH) and an isocyanate group in addition to the main chain skeleton of the polyester.

The specific polyester preferably has a hydroxyl group for the reason that it is more excellent in adhesion to vulcanized rubber.
When the specific polyester has hydroxyl groups, the specific polyester may further have carboxy groups and/or isocyanate groups in addition to hydroxyl groups.

(hydroxyl group)
The specific polyester preferably has a hydroxyl group.
The hydroxyl value of the specific polyester is preferably 2 to 30 mgKOH/g for the reason that the adhesion to vulcanized rubber is superior.
The hydroxyl value of the specific polyester can be measured according to JIS K1557-1:2007.

(Carboxy group)
The specific polyester may further have a carboxy group.
The acid value of the specific polyester can be, for example, less than 3 mgKOH/g.
The acid value of the specific polyester can be measured according to JIS K0070:1992.

(isocyanate group)
The specific polyester may further have an isocyanate group.
Examples of the isocyanate group include those derived from an isocyanate component having a plurality of isocyanate groups, which is used as a modifier for urethane modification of a specific polyester, which will be described later.

(Connecting group)
The functional group can be bonded directly or via a linking group to the polyester that is the main chain skeleton.
The linking group is not particularly limited.
When the functional group is an isocyanate group, the isocyanate group can be bonded to the polyester, which is the main chain skeleton, via a linking group containing a urethane bond, for example.

Specific polyesters include, for example, polyesters obtained by condensation polymerization of an acid component and a polyol.
Examples of the acid component used in producing the specific polyester include terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, and diphenyldicarboxylic acid. acids, diphenyl ether dicarboxylic acid, aromatic dicarboxylic acids such as 5-sodium sulfonephthalic acid,
such as aromatic tricarboxylic acids such as trimellitic acid,
Aromatic polycarboxylic acid (aromatic hydrocarbon compound having multiple carboxy groups);
Aliphatic polycarboxylic acids (aliphatic hydrocarbon compounds having a plurality of carboxy groups) such as aliphatic dicarboxylic acids such as succinic acid, adipic acid, azelaic acid, sebacic acid and dimer acid can be used.
The acid component preferably contains an aliphatic polycarboxylic acid for the reason that the adhesion to the vulcanized rubber is superior.

Examples of polyols used in producing the specific polyester include ethylene glycol, diethylene glycol, triethylene glycol, trimethylene glycol, propylene glycol, 1,3-propanediol, tetramethylene glycol, 1,2- Butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, octamethylene glycol, decamethylene glycol, neopentyl glycol, polyethylene glycol (excluding diethylene glycol and triethylene glycol), and glycols such as 2-methyl-1,3-propanediol.
The above polyol preferably contains 1,4-butanediol or 1,6-hexanediol for the reason of better adhesion to vulcanized rubber.

(urethane modification)
When the specific polyester is urethane-modified, it may hereinafter be referred to as "urethane-modified polyester".
A urethane-modified polyester can have one or more urethane bonds.

The polyester used for the urethane modification is not particularly limited. For example, the above specific polyester may further have a hydroxyl group.
The modifier used for the urethane modification is not particularly limited. The modifier may be an isocyanate component having one or more isocyanate groups. Examples of the modifier (isocyanate component) include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, diphenylmethane diisocyanate (MDI), m-phenylene diisocyanate, p-phenylene diisocyanate, 3,3′-dimethoxy -4,4'-biphenylene diisocyanate, 1,5-naphthalene diisocyanate, 2,6-naphthalene diisocyanate, 3,3'-dimethyl-4,4'-biphenylene diisocyanate, 4,4'-diisocyanate diphenyl ether, xylylene diisocyanate, aromatic diisocyanates such as tetramethylxylylene diisocyanate (TMXDI) and tolidine diisocyanate (TODI);
Fats such as hexamethylene diisocyanate, tetramethylene diisocyanate, 1,3-diisocyanatomethylcyclohexane, 1,4-diisocyanatomethylcyclohexane, 4,4'-diisocyanatocyclohexane, 4,4'-diisocyanatocyclohexylmethane, isophorone diisocyanate, etc. (the above aliphatic is a concept including linear, branched and alicyclic) diisocyanates.
The modifier is preferably an aromatic diisocyanate, more preferably diphenylmethane diisocyanate (MDI), because of its excellent adhesion to the vulcanized rubber.

Regarding the presence or absence of urethane modification, the specific polyester preferably contains urethane-modified polyester for the reason that it is more excellent in adhesion to vulcanized rubber.

The weight-average molecular weight of the specific polyester is preferably 10,000 to 30,000 from the viewpoint of superior adhesion to vulcanized rubber.
The weight average molecular weight of the specific polyester can be measured by gel permeation chromatography using tetrahydrofuran as a solvent.

When the specific polyester further has a hydroxyl group, the specific polyester in the above case can have one or more hydroxyl groups per molecule. From the viewpoint of better adhesion to vulcanized rubber, the specific polyester in the above case preferably has an average of 2 to 3 hydroxyl groups per molecule.
In addition, the hydroxyl group does not include the OH of the carboxy group.

(NCO/OH)
When the specific polyester further has a hydroxyl group, the molar ratio of the isocyanate group of the polyisocyanate compound to the hydroxyl group of the specific polyester (NCO/OH, also referred to as an index) is said to be superior in adhesion to the vulcanized rubber. From the viewpoint, it is preferably 5.0 to 15.0, more preferably 7.0 to 12.0.
In calculating the molar ratio, the hydroxyl group does not include the OH of the carboxyl group that the specific polyester may have.

(filler)
The composition of the invention can further contain fillers.
It is preferable that the composition of the present invention further contains a filler from the standpoint of better adhesion to vulcanized rubber.

Examples of the filler include clay, silica, and calcium carbonate.
The filler may be surface-treated. The surface treatment agent used for surface treatment is not particularly limited. Examples include fatty acids, resin acids, urethane compounds, and fatty acid esters.

Clay is preferable as the filler from the viewpoint of excellent adhesion to the vulcanized rubber.
Examples of the clay include bentonite.
Naturally occurring bentonites usually contain impurities such as quartz and feldspar in addition to clay minerals (eg, montmorillonite).
The clay is preferably bentonite, and more preferably purified bentonite, from the viewpoint of excellent adhesion to vulcanized rubber.
Purified bentonite means purified bentonite in which the purity of montmorillonite, which is the main component, is higher than that of naturally occurring bentonite.

(filler content)
The content of the filler is preferably 10 to 70% by mass with respect to the total amount of the composition of the present invention (the polyurethane adhesive composition) from the viewpoint of better adhesion to vulcanized rubber. 20 to 50% by mass is more preferable.

(plasticizer)
It is preferable that the composition of the present invention further contain a plasticizer from the standpoint of better adhesion to vulcanized rubber.

Examples of the plasticizer include ester compounds such as diisononyl phthalate (DINP), dioctyl adipate, isodecyl succinate, diethylene glycol dibenzoate, and butyl oleate;
aroma oil;
Examples thereof include compound A represented by the following formula (1).
In formula (1), R ¹ is an amino group (—NH ₂ ), a hydrogen atom, or a hydrocarbon group, R ² and R ³ are each independently a hydrocarbon group optionally having a heteroatom, Alternatively, it is a hydrogen atom.

The plasticizer is preferably the compound A represented by the above formula (1) from the viewpoint of superior adhesion to the vulcanized rubber.
The inventors presume that this is because the compound A represented by the formula (1) as a plasticizer can permeate the vulcanized rubber.
Therefore, when the composition of the present invention further contains the compound A and is applied to vulcanized rubber, the compound A permeates the vulcanized rubber, and along with the permeation of the compound A, the polyisocyanate and The present inventor believes that the above-mentioned specific polyester also permeates the vulcanized rubber and that the anchoring effect of the above-mentioned polyisocyanate and/or the above-mentioned specific polyester can be obtained.

(Compound A)
The compound A is a compound represented by the following formula (1).
In formula (1), R ¹ is an amino group (—NH ₂ ), a hydrogen atom, or a hydrocarbon group, R ² and R ³ are each independently a hydrocarbon group optionally having a heteroatom, Alternatively, it is a hydrogen atom.

In the above formula (1), the hydrocarbon group as R ¹ is not particularly limited. Examples of hydrocarbon groups include aliphatic hydrocarbon groups (including linear, branched, and cyclic), aromatic hydrocarbon groups, and combinations thereof. The hydrocarbon group may have an unsaturated bond.
The number of carbon atoms in the hydrocarbon group is preferably 20 or less, more preferably 1-15.
Examples of hydrocarbon groups include aliphatic hydrocarbon groups such as methyl, ethyl, butyl, pentyl, hexyl, octyl, decyl and dodecyl groups.

In the above formula (1), the heteroatom is not particularly limited. Heteroatoms include, for example, oxygen atoms, nitrogen atoms, sulfur atoms, halogens, and the like. A heteroatom may be combined with another heteroatom, carbon atom or hydrogen atom to form a functional group.
When R ¹ is an amino group, R ² and R ³ are preferably each independently a hydrocarbon group or a hydrogen atom.
When R ¹ is a hydrogen atom, R ² and R ³ are each independently a hydrocarbon group, or R ² is a hydrocarbon group and R ³ is a hydrogen atom.

Compound A includes, for example, compounds in which R ¹ is an amino group; compounds in which R ¹ is a hydrogen atom; and compounds in which R ¹ is a hydrocarbon group.
Compounds in which R ¹ is an amino group include, for example, urea (NH ₂ CONH ₂ ).
Compounds in which R ¹ is a hydrogen atom include, for example, N,N-dimethylformamide and N-methyl-N-isopropylformamide.
Compounds in which R ¹ is a hydrocarbon group include, for example, N,N-dimethylacetamide and N-methyl-N-isopropylacetamide.

The compound A is preferably a compound in which R ¹ is an amino group, a compound in which R ¹ is a hydrogen atom, and urea, N,N-dimethyl Formamide is more preferred.

(SP value of plasticizer)
The SP value of the plasticizer is preferably 20 (MPa) ^1/2 or more from the viewpoint of excellent adhesion to vulcanized rubber and high anchoring effect.
The upper limit of the SP value is not particularly limited. For example, it can be 30 (MPa) ^1/2 or less.

In the present invention, the SP value (solubility parameter) was calculated by applying the molecular volume and molecular cohesive energy values in the literature Properties of Polymers 3rd Edition Part 3 and Part 4 to the chemical structures of polyurethane and epoxy resins.

Plasticizers having an SP value of 20 (MPa) ^1/2 or more include, for example, urea and N,N-dimethylformamide.

(Molecular weight of plasticizer)
The molecular weight of the plasticizer is preferably 1,000 or less, more preferably 50 to 200, and even more preferably 60 to 100, from the viewpoints of excellent adhesion to vulcanized rubber and high anchoring effect.

The molecular weight of the plasticizer can be measured, for example, by a conventionally known method.
When the plasticizer is a low-molecular-weight compound (not a polymer), the molecular weight of the plasticizer may be measured, for example, by a conventionally known method.

(Plasticizer content)
The content of the plasticizer is 0.4 to 20% by mass relative to the total amount of the composition of the present invention (the polyurethane-based adhesive composition) from the viewpoint of better adhesion to vulcanized rubber. is preferred, 0.8 to 15 mass % is more preferred, 1 to 10 mass % is even more preferred, and 3 to 10 mass % is even more preferred.

The compositions of the present invention can be one-part or two-part.
(Two-component adhesive composition)
When the composition of the present invention is of a two-component type, the two-component adhesive composition can have a main agent and a curing agent (curing agent in a broad sense).
- Main agent The above-mentioned main agent should just contain the above-mentioned polyisocyanate compound at least. The main agent may be only the polyisocyanate compound.

Curing agent The (broadly defined) curing agent may contain a compound (narrowly defined curing agent) having a plurality of active hydrogen-containing groups in one molecule. The narrowly defined curing agent means a compound that substantially reacts with the polyisocyanate compound to cure the adhesive composition. The curing agent in the broad sense should include at least the curing agent in the narrow sense.
Examples of the curing agent in the narrow sense include those in which the specific polyester further has a hydroxyl group, a carboxyl group, or an isocyanate group.

(other optional ingredients)
The composition of the present invention, if necessary, within a range that does not impair the purpose of the present invention, a polyester other than the specific polyester, a curing catalyst, an antioxidant, an antioxidant, a silane coupling agent, a pigment (dye), an adhesive Various additives such as imparting agents, thixotropic agents, ultraviolet absorbers, flame retardants, surfactants (including leveling agents), dispersants, dehydrating agents, antistatic agents, organic solvents, etc. can be further included. .
Moreover, when the composition of the present invention is of a two-pack type, it can be appropriately selected whether the optional component is added to the main agent or the curing agent.

Curing catalyst The curing catalyst is not particularly limited, but specific examples include carboxylic acids such as 2-ethylhexanoic acid and oleic acid; phosphoric acids such as polyphosphoric acid, ethyl acid phosphate and butyl acid phosphate; and bismuth octylate. bismuth catalysts such as; dibutyltin dilaurate, dioctyltin dilaurate and other tin-based catalysts; ), tertiary amine catalysts such as compounds containing a dimorpholinodiethyl ether structure, and the like.
The curing catalyst is preferably a tin-based catalyst.
The amount of curing catalyst can be selected as appropriate.

(Production method)
When the composition of the present invention is a one-liquid type, its production method is not particularly limited. be able to.

When the composition of the present invention is a two-component composition, the production method is not particularly limited. For example, the main component and the curing agent are placed in separate containers, and mixed in each container under a nitrogen gas atmosphere. It can be manufactured by a method.
Moreover, as a method of using a two-liquid type, the main agent and the curing agent may be mixed and used.

<Applied to vulcanized rubber>
The compositions of the invention are applied to vulcanizates.
The vulcanized rubber to which the composition of the present invention is applied is not particularly limited as long as it is vulcanized rubber (rubber after vulcanization).
The vulcanization is preferably sulfur vulcanization.
Examples of the vulcanized rubber include natural rubber (NR), isoprene rubber (IR), butadiene rubber (BR), aromatic vinyl-conjugated diene copolymer rubber (eg, styrene-butadiene rubber), acrylonitrile-butadiene copolymer rubber. (NBR), butyl rubber (IIR), halogenated butyl rubber (Br-IIR, Cl-IIR), and diene rubbers such as chloroprene rubber (CR).

The vulcanized rubber preferably contains a halogenated butyl rubber from the viewpoint of excellent adhesion to the composition of the present invention.
The vulcanized rubber may further contain a non-diene rubber and a thermoplastic resin in addition to the diene rubber.

In addition to the rubber component, the vulcanized rubber further contains a filler such as carbon black or silica, a silane coupling agent, zinc oxide, stearic acid, an anti-aging agent, a processing aid, an oil (for example, a process Various additives commonly used in rubber compositions such as oils, aromatic oils), liquid polymers, vulcanizing agents (eg, sulfur), and vulcanization accelerators can be included.

Examples of the vulcanized rubber include diene-based rubbers, non-diene-based rubbers that can be used as necessary, thermoplastic resins, and vulcanized rubber compositions containing the various additives described above.
The vulcanization conditions are not particularly limited.

As a method of using the composition of the present invention, for example, first, the composition of the present invention is applied to vulcanized rubber (application step).
The method of applying the composition of the present invention to vulcanized rubber is not particularly limited.
When the composition of the present invention is applied to vulcanized rubber, the thickness can be, for example, 0.5 to 2.0 mm.

(vulcanized rubber)
The composition of the present invention is capable of bonding vulcanized rubber as described above.
In addition, the composition of the present invention can adhere vulcanized rubbers together.
At this time, the types of vulcanized rubber may be the same or different.
When the composition of the present invention is used to bond vulcanized rubbers together, the composition of the present invention can be applied to one vulcanized rubber or both vulcanized rubbers.

Examples of the vulcanized rubber as a member include vulcanized rubber forming the inner or outer surface of a tire, and vulcanized rubber as a case for housing an electronic device.
When vulcanized rubber is used as the case, the case may cover the whole or part of the electronic device, for example.
The electronic device housed in the case is not particularly limited.

Using the composition of the present invention, for example, when bonding vulcanized rubber X constituting the inside or outside of a tire and vulcanized rubber Y containing electronic equipment, first, one vulcanized rubber or both vulcanized rubbers The composition of the present invention may be applied to sulfur rubber.
Next, the vulcanized rubber X and the vulcanized rubber Y may be arranged so that the composition of the present invention is interposed therebetween.

Curing step Next, the vulcanized rubber to which the composition of the present invention is applied is cured under conditions of, for example, 10 to 80 ° C. and 20 to 80% relative humidity (% RH) to obtain the A laminate having an adhesive layer (polyurethane-based adhesive) made of the composition can be obtained.
In addition, when a plurality of vulcanized rubbers are arranged through the composition of the present invention, the plurality of vulcanized rubbers arranged through the composition of the present invention, for example, under the same conditions as above By placing and curing, a laminate having an adhesive layer (polyurethane-based adhesive) made of the composition of the present invention interposed therebetween can be obtained.

The polyurethane-based adhesive composition of the present invention means that the composition of the present invention is a composition capable of becoming a polyurethane-based adhesive (adhesive layer) after curing.
In the present invention, the "polyurethane-based" means that the isocyanate group of the polyisocyanate compound contained in the composition of the present invention reacts, and the adhesive layer after the reaction becomes a polyurethane-based compound. The polyurethane-based compound is formed by reaction of the isocyanate groups (e.g., reaction between isocyanate groups, reaction between isocyanate groups and other groups (e.g., hydroxy groups, etc.), such as urea bond, urethane bond, etc. Any compound having a bond may be used.

EXAMPLES The present invention will be specifically described below with reference to examples. However, the present invention is not limited to these.

<Production of adhesive composition>
Each component shown in Table 1 below was used in the composition (parts by mass) shown in the same table.
In this example, the adhesive composition was of a two-liquid type.
The polyisocyanate compound shown in Table 1 below was used as the main component of the two-component adhesive composition.
On the other hand, each curing agent was obtained by mixing components other than the polyisocyanate compound shown in Table 1 below.
The amount of specific polyester 2 shown in Table 1 is the net amount of urethane-modified polyester resin.
The main agent and each curing agent obtained as described above were mixed with a stirrer to produce an adhesive composition.

<Evaluation (vulcanized rubber adhesion)>
Using each adhesive composition produced as described above, the following evaluation of vulcanized rubber adhesion (adhesion to vulcanized rubber) was performed. The results are shown in Table 1.

For evaluation of vulcanized rubber adhesion, first, vulcanized rubber was prepared as follows.
・Preparation of vulcanized rubber From the components shown in the following "rubber composition for vulcanized rubber", the components excluding sulfur and vulcanization accelerator were kneaded for 5 minutes in a 1.8 L closed type mixer and discharged to make a masterbatch. . A rubber composition was prepared by adding sulfur and a vulcanization accelerator to the obtained masterbatch and mixing with an open roll.
The rubber composition prepared as described above was vulcanized at 170° C. for 10 minutes in a mold of a predetermined shape to produce a vulcanized rubber.

((Rubber composition for vulcanized rubber))
・ 100 parts by mass of halogenated butyl rubber (brominated isobutylene isoprene rubber, manufactured by EXXON CHEMICAL)
・ 25 parts by mass of carbon black (Niteron #GN, N ₂ SA manufactured by Shin Nikka Carbon Co., Ltd. is 35 m ² /g
・ 3 parts by mass of zinc oxide (3 types of zinc oxide manufactured by Seido Chemical Industry Co., Ltd.)
・ Sulfur 3 parts by mass (Sulfax 5 manufactured by Tsurumi Chemical Industry Co., Ltd.)
・ 2 parts by mass of vulcanization accelerator (DM-PO manufactured by Ouchi Shinko Chemical Industry Co., Ltd.)

- Preparation of test body - Application step Each adhesive composition produced as described above was applied to the vulcanized rubber with a brush to a thickness of 1.0 mm.

Curing step The vulcanized rubber coated with the adhesive composition is placed under conditions of 25 ° C. and 50% relative humidity for 180 minutes to cure, and an adhesive layer (polyurethane adhesive) is formed on the vulcanized rubber by the adhesive composition. agent) was obtained.

· Cross-cut test The adhesive layer of the above specimen is cut at a pitch of 1 mm with a cutter knife to create 100 base meshes (10 rows × 10 columns), and cellophane adhesive tape (width 18 mm) was completely adhered, and immediately, a cross-cut peel test was performed in which one end of the tape was held perpendicular to the vulcanized rubber and instantaneously separated.
After the cross-cut peeling test, the number of base stitches remaining on the vulcanized rubber was examined.

·Evaluation Criteria When the number of base stitches remaining on the vulcanized rubber was 10 or more, it was evaluated as having excellent adhesion to the vulcanized rubber (to each other).
When the number of base stitches was 10 or more, it was evaluated that the larger the number, the more excellent the adhesiveness to vulcanized rubber (to each other).
When the number of base stitches was less than 10, it was evaluated as having poor adhesion to vulcanized rubber (to each other).

Details of each component shown in Table 1 are as follows.
Polyisocyanate compound Polymeric MDI: Polymeric MDI (trade name Sumidule 44V10, manufactured by Sumika Bayer Urethane) melting point -25°C (liquid at room temperature). Average number of isocyanate functional groups per molecule: 2.4

(polyester)
- Specific Polyester 1 Vylon 550: polyester resin. Made by Toyobo. Glass transition temperature -15°C. Weight average molecular weight 25,000. Hydroxyl value 4 mgKOH/g. Acid value less than 2 mgKOH/g. Vylon 550 is a copolymer of 1,6-hexanediol, an aliphatic polycarboxylic acid and terephthalic acid. Not urethane modified. It has three hydroxyl groups per molecule.

- Specific polyester 2 Vylon UR3200: urethane-modified polyester resin. Made by Toyobo. Glass transition temperature -5°C. Weight average molecular weight 25,000. Urethane modified polyester resin. A urethane-modified polyester resin obtained by polyurethane-forming an OH-terminated polyester obtained by copolymerizing 1,4-butanediol and an aliphatic polycarboxylic acid with diphenylmethane diisocyanate (MDI). It has an average of 2.5 hydroxyl groups per molecule. Solid content concentration 30% by mass

- Comparative polyester 1 Vylon 500: Polyester resin. Made by Toyobo. Glass transition temperature +6°C. Weight average molecular weight 25,000. Not urethane modified. It has an average of two hydroxyl groups per molecule.
• Comparative polyester 2 Vylon 200: polyester resin. Made by Toyobo. Glass transition temperature +67°C. Weight average molecular weight 25,000. Not urethane modified. It has an average of two hydroxyl groups per molecule.

(Plasticizer)
· Plasticizer 1 DINP: diisononyl phthalate (DINP), manufactured by J-Plus. SP value 16.5 (MPa) ^1/2 . Molecular weight 419.
· Plasticizer 2 Aroma oil: trade name Dianafrecia 32, manufactured by Idemitsu Petrochemical Co., Ltd. SP value 14.5 (MPa) ^1/2 . molecular weight 650

· Plasticizer 3 dimethylformamide: manufactured by Wako Pure Chemical Industries, Ltd. SP value 20.1 (MPa) ^1/2 . molecular weight 73; It corresponds to the compound A represented by the above formula (1).
· Plasticizer 4 Urea: manufactured by Wako Pure Chemical Industries, Ltd. SP value 22 (MPa) ^1/2 . molecular weight 60; It corresponds to the compound A represented by the above formula (1).

・Organic solvent: Cyclohexane

(filler)
- Filler 1 Bentonite: Product name: Kunipia, manufactured by Kunimine Industries. Purified bentonite Filler 2 Silica: trade name R923, manufactured by Nippon Aerosil Co., Ltd. Filler 3 Surface-treated calcium carbonate: trade name Kalfine 200, manufactured by Maruo Calcium Co., Ltd.

As is clear from the results shown in Table 1, when Comparative Examples 1 and 2, which do not contain a specific polyester and instead contain a polyester whose glass transition temperature exceeds a predetermined range, are applied to the vulcanized rubber, Adhesion to vulcanized rubber was poor.

In contrast, the composition of the present invention was able to be applied to vulcanized rubber to adhere the vulcanized rubber.

Claims (9)

a polyisocyanate compound;
It contains a polyester that has a glass transition temperature of -25 to 0 ° C. and may be urethane-modified,
the polyester further has a hydroxyl group,
The molar ratio (NCO/OH) of the isocyanate groups of the polyisocyanate compound to the hydroxyl groups of the polyester is 5.0 to 15.0,
A polyurethane adhesive composition applied to vulcanized rubber. a polyisocyanate compound;
A polyester that has a glass transition temperature of -25 to 0°C and may be urethane-modified,
a filler, wherein the filler is clay;
Polyurethane adhesive composition applied to vulcanized rubber. a polyisocyanate compound;
A polyester that has a glass transition temperature of -25 to 0°C and may be urethane-modified,
and an organic solvent,
Polyurethane adhesive composition applied to vulcanized rubber. The polyurethane-based adhesive composition according to any one of claims 1 to 3 , wherein the polyisocyanate compound is liquid at room temperature. 3. The polyurethane-based adhesive composition according to claim 2 , wherein the content of said filler is 10 to 70% by mass with respect to the total amount of said polyurethane-based adhesive composition. The polyurethane-based adhesive composition according to any one of claims 1 to 5 , further comprising a plasticizer. The polyurethane-based adhesive composition according to claim 6 , wherein the plasticizer has an SP value of 20 (MPa) ^1/2 or more. 8. The polyurethane-based adhesive composition according to claim 6 , wherein the plasticizer has a molecular weight of 1,000 or less. The polyurethane adhesive composition according to any one of claims 6 to 8 , wherein the content of said plasticizer is 1 to 20% by mass relative to the total amount of said polyurethane adhesive composition.