JP2009280689A - Adhesive composition for tire label - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an adhesive composition for tire labels, which is excellent in adhesiveness and environmental protection, ensures flexibility, improves dynamic durability, and is suitable for adhering to the surfaces of tire sidewall portions. <P>SOLUTION: Provided is the adhesive composition for adhering a tire label 1 to the surface Ta of the sidewall portion T1 of a tire T, characterized by containing a urethane prepolymer having a plurality of isocyanate group terminals in a molecule as a main component, containing a ketimine in an amount of 0.8 to 1.4 equivalents per equivalent of the isocyanate group, compounding a polyisocyanate oligomer in an amount of 0 to 40 pts.wt. per 100 pts.wt. of the urethane prepolymer, and having a stress on 1 to 50% tensile deformation of the adhesive composition, after cured, in a quantity of ≤1.5 times a stress, when the tensile deformation of the surface rubber of the sidewall portion is identical. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  TECHNICAL FIELD The present invention relates to an adhesive composition for tire labels, and more specifically, it is excellent in adhesion and environmental conservation, secures flexibility and improves dynamic durability, thereby providing tires on the surface of sidewall portions of tires. The present invention relates to an adhesive composition for a tire label suitable for attaching a label.

  There is a tire label that displays a logo or the like that is affixed to the surface of a sidewall portion of a pneumatic tire for decoration or the like (see, for example, Patent Document 1). As a method of attaching such a tire label to the sidewall portion surface, there are a method by vulcanization adhesion and a method using an adhesive. Since the method using an adhesive is simpler than vulcanization bonding, there is an advantage that a user can easily attach a tire label that suits his / her preference to a purchased pneumatic tire.

However, since the surface of the sidewall portion of the pneumatic tire is composed of vulcanized rubber, conventional urethane, epoxy and silicone adhesives are excluded except chloroprene rubber adhesives and cyanoacrylate adhesives. Then, sufficient adhesive strength could not be obtained. Moreover, since the chloroprene rubber adhesive contains a large amount of toluene as a solvent, it should not be used for environmental protection. In addition, the chloroprene rubber adhesive has sufficient peel strength statically, but because it peels when subjected to repeated expansion and contraction and centrifugal force during tire running, like the sidewall surface of a pneumatic tire, It could not be used for bonding with tires. Although the cyanoacrylate adhesive has a sufficient peel strength statically, it does not have flexibility after curing, so it peels off during running of the tire and is insufficient in dynamic durability and cannot be used.
Japanese Patent Laid-Open No. 10-187044

  An object of the present invention is a tire label suitable for adhering a tire label to the surface of a sidewall portion of a tire by ensuring flexibility and improving environmental durability while being excellent in adhesiveness and environmental conservation. It is to provide an adhesive composition.

  An adhesive composition for a tire label of the present invention that achieves the above object is an adhesive composition for a tire label that adheres a tire label to the surface of a sidewall portion of a tire, and the adhesive composition is a molecule. The main component is a urethane prepolymer having a plurality of isocyanate group ends therein, and ketimine is included in an amount of 0.8 to 1.4 equivalents relative to the isocyanate group, and an optional component is added to 100 parts by weight of the urethane prepolymer. When 0 to 40 parts by weight of isocyanate oligomer is blended, and the stress at the time of tensile deformation of 1% to 50% of the adhesive composition after curing makes the amount of tensile deformation of the rubber on the side wall part the same. The stress is 1.5 times or less.

  The ketimine may be a reaction product of a polyamine and a ketone having a side chain at the α-position carbon atom.

  This adhesive composition for tire labels can be suitably used when a tire label is stuck on a sidewall portion of a pneumatic tire.

  The tire label adhesive composition of the present invention comprises, as a main component, a urethane prepolymer having a plurality of isocyanate group ends in the molecule and ketimine as a curing agent in an amount of 0.8 to 1.4 equivalents relative to isocyanate groups. In addition, since polyisocyanate oligomer is blended as an optional component in an amount of 0 to 40 parts by weight with respect to 100 parts by weight of the urethane prepolymer, it is excellent in environmental conservation and has an adhesive force between the tire label and the tire sidewall surface. Can be high. Moreover, when the relationship between the stress at the time of tensile deformation between 1% to 50% between the adhesive composition after curing and the rubber constituting the surface of the sidewall portion is the same, the amount of the tensile composition is the same. Since the stress is 1.5 times or less of the stress of the rubber on the surface of the sidewall part, the flexibility of the adhesive composition after curing is maintained even on the surface of the sidewall part where the deformation during running of the tire is large, Dynamic durability can be improved.

  1A and 1B show an example of a tire label, where FIG. 1A is a plan view, FIG. 1B is a side view seen from the k direction of FIG. It is a side view which shows an example of a entering tire, 1 is a tire label and T is a pneumatic tire.

  1A and 1B, a tire label 1 is composed of a base material layer 2 and a cover layer 3, and a logo, a mark or the like is printed on the surface 2a of the base material layer 2 on the cover layer 3 side by silk printing or offset printing. Design is given. The surface 2b on the opposite side of the base material layer 2 is attached to the surface of the sidewall portion of the pneumatic tire T via an adhesive. The base material layer 2 is made of an elastic material mainly composed of a rubber component such as natural rubber or synthetic rubber, and gives flexibility to the tire label 1 formed by being laminated with the cover layer 3. As the elastic material constituting the base material layer 2, styrene butadiene rubber, acrylonitrile butadiene rubber, and chloroprene rubber are preferable. The cover layer 3 is made of a flexible and transparent resin, and examples thereof include a polyester resin, a polyolefin resin, a polyurethane resin, and the like. Among these, a polyurethane resin is preferable.

  As shown in FIG. 2, the tire label 1 is attached to the surface Ta of the sidewall portion T1 of the pneumatic tire T with an adhesive. The surface Ta of the sidewall portion T1 of the pneumatic tire T is formed, for example, by vulcanizing a natural rubber, isoprene rubber, butadiene rubber, styrene butadiene rubber, acrylonitrile butadiene rubber, butyl rubber or the like or a rubber composition blended with these. ing. Therefore, sufficient adhesive strength could not be obtained even if the tire label was attached using a conventional urethane, epoxy, or silicone adhesive. Further, as described above, although the chloroprene rubber adhesive has a large adhesive strength, it should not be used for environmental protection because it contains a large amount of toluene as a solvent. In addition, since the cyanoacrylate adhesive has no flexibility after curing, there is a problem inherent to a pneumatic tire that the tire label is peeled off during running of the tire and the dynamic durability is insufficient.

  Even if the adhesive composition for tire labels of the present invention is used on the surface of a tire sidewall portion that repeatedly undergoes large deformation during tire running, the cured adhesive composition maintains flexibility, so tire running Sometimes the label does not peel off, and the dynamic durability is excellent.

  In the present invention, the relationship of flexibility between the cured adhesive composition and the rubber constituting the surface of the sidewall portion of the tire is the same when the amount of tensile deformation is the same at the time of 1% to 50% tensile deformation. With respect to the stress, the stress of the adhesive composition is 1.5 times or less, preferably 1.0 times or less, the stress of the rubber constituting the sidewall portion surface. If the stress of the adhesive composition after curing is higher than 1.5 times the stress of rubber, the flexibility will be insufficient and it will not be possible to follow changes in the surface of the sidewall during tire running, and peeling will occur easily. Dynamic durability deteriorates. Further, the lower limit of the stress of the adhesive composition is not particularly limited, but is preferably about 0.2 times the stress of rubber in order to ensure adhesion.

  In the present invention, the cured adhesive composition and the stress of the rubber constituting the surface of the sidewall portion of the tire are subjected to a tensile test in accordance with JIS K6251 at a tensile speed of 500 mm / min. Each stress is in the range of 1% to 50%.

  The tire label adhesive composition of the present invention is mainly composed of a urethane prepolymer having a plurality of isocyanate group terminals in the molecule. The urethane prepolymer is preferably liquid at room temperature from the viewpoint of handling. A urethane prepolymer is a reaction product obtained by reacting a polyol compound and a polyisocyanate compound, and is a polymer containing a plurality of isocyanate groups at the molecular ends. This isocyanate group may be bonded to either an aromatic hydrocarbon or an aliphatic hydrocarbon.

  Examples of the polyisocyanate compound include 2,4-tolylene diisocyanate (2,4-TDI), 2,6-tolylene diisocyanate (2,6-TDI), 4,4′-diphenylmethane diisocyanate (MDI), 2 , 4'-diphenylmethane diisocyanate (2,4'-MDI), 1,4-phenylene diisocyanate, polymethylene polyphenylene polyisocyanate, tolidine diisocyanate (TODI), 1,5-naphthalene diisocyanate (NDI), hexamethylene diisocyanate (HDI) Xylylene diisocyanate (XDI), isophorone diisocyanate (IPDI), tetramethylxylylene diisocyanate (TMXDI), and the like. A polyisocyanate compound can be used individually or in combination of 2 types or more, respectively.

  It does not specifically limit as a polyol compound, For example, any of polyether polyol, polyester polyol, acrylic polyol, polycarbonate polyol, and another polyol may be sufficient. These polyols may be used alone or in combination. Specifically, polyethylene glycol, polypropylene glycol, polyoxyethylene glycol, polyoxypropylene glycol, polyoxypropylene triol, polytetramethylene ether glycol, polymer polyol, poly (ethylene adipate), poly (diethylene adipate), poly (propylene) Adipate), poly (tetramethylene adipate), poly (hexamethylene adipate), poly (neopentylene adipate), poly-ε-caprolactone, poly (hexamethylene carbonate), silicone polyol and the like are preferable. A natural polyol compound such as castor oil may be used.

  Moreover, since the polyol compound has excellent physical properties after curing, a polyether polyol having a number average molecular weight of 1500 to 15000 is preferable, and a polyether polyol having 2000 to 10,000 is more preferable.

  The combination of the polyol compound and the polyisocyanate compound is not particularly limited, and each of the polyol compound and each of the polyisocyanate compound can be arbitrarily combined. Specifically, for example, it is obtained from at least one selected from the group consisting of polyoxyethylene glycol, polyoxypropylene glycol and polyoxypropylene triol and at least one selected from the group consisting of TDI, MDI and XDI. Urethane prepolymers are preferred from the viewpoints of physical property adjustment, cost, and availability.

  The mixing ratio of the polyol compound and the polyisocyanate compound is preferably such that the molar ratio (NCO / OH) of the isocyanate group in the polyisocyanate compound to the hydroxy group in the polyol compound is 1.3 to 2.5. More preferably, it is 5 to 2.3. In such a range, the viscosity of the urethane prepolymer is moderate and the elongation of the cured product is excellent.

  The reaction between the polyol compound and the polyisocyanate compound is not particularly limited, and examples thereof include a method in which the polyol compound and the polyisocyanate compound having the above-mentioned quantitative ratio are heated and stirred at 50 to 100 ° C. It is done. If necessary, a urethanization catalyst such as an organic tin compound, an organic bismuth, or a tertiary amine can be used.

  The adhesive composition for tire labels of the present invention contains ketimine as a curing agent. Ketimine is a compound that can generate primary amines by hydrolysis. In the present invention, a compound having a> C═N bond (ketimine bond) derived from a carbonyl compound and an amine is referred to as a ketimine. Therefore, it also includes aldimine having a —HC═N bond.

  The ketimine preferably has, for example, a structure in which a branched carbon atom or a ring member carbon atom is bonded to the α-position of the carbon atom of the ketimine bond, and more preferably has a branched carbon atom in the α-position. As a ring member carbon atom, the carbon atom which comprises an aromatic ring and the carbon atom which comprises an alicyclic ring are mentioned, for example.

  Ketimines include, for example, ketimines that are reaction products of polyamines or aminoalkoxysilanes and carbonyl compounds. The carbonyl compound is preferably a ketone or aldehyde having a side chain at the α-position carbon atom of the carbonyl carbon atom because of excellent balance between storage stability and curing rate.

  Examples of ketones include, for example, methyl ethyl ketone (MEK), methyl isopropyl ketone (MIPK), methyl t-butyl ketone (MTBK), methyl isobutyl ketone (MIBK), methyl cyclohexyl ketone, methyl cyclohexanone, diisobutyl ketone (DIBK) and the like. can do. Examples of aldehydes include paviraldehyde, isopropyl aldehyde, isobutyraldehyde, and the like. These carbonyl compounds can be used alone or in combination of two or more.

The polyamine used for the ketimine raw material is not particularly limited as long as it has two or more amino groups. Of these, aliphatic polyamines are preferred from the viewpoint of excellent curing speed. Examples of the polyamine include 2,5-dimethyl-2,5-hexamethylenediamine, mensendiamine, 1,4-bis (2-amino-2-methylpropyl) piperazine, and amino group at the propylene branched carbon at both ends of the molecule. Group-bound polypropylene glycol (PPG), ethylenediamine, propylenediamine, butylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, hexamethylenediamine (HMDA), trimethylhexamethylenediamine, N-aminoethylpiperazine , 1,2-diaminopropane, iminobispropylamine, methyliminobispropylamine, and a methylene group bonded to amine nitrogen such as H ₂ N (CH ₂ CH ₂ O) ₂ (CH ₂ ) ₂ NH _2. Polyether skeleton diamine, 1,5-diamino-2-methylpentane, metaxylylenediamine (MXDA), polyamidoamine, isophorone diamine, 1,3-bisaminomethylcyclohexane (1,3BAC), 1-cyclohexylamino -3-aminopropane, 3-aminomethyl-3,3,5-trimethyl-cyclohexylamine, norbornanediamine (NBDA). Among these, since the curing speed is high, norbornanediamine (NBDA), hexamethylenediamine (HMDA), 1,3-bisaminomethylcyclohexane, metaxylylenediamine, H ₂ N (CH ₂ CH ₂ O) ₂ ( CH ₂ ) ₂ NH ₂ and polyamidoamine are preferred. Polyamines can be used alone or in combination of two or more.

  In particular, the ketimine may comprise a reaction product of a polyamine and a ketone having a side chain on the α-position carbon atom. As such ketimines, those obtained from MIPK, MIBK or MTBK and norbornanediamine (NBDA), those obtained from MIPK or MTBK and 1,3-bisaminomethylcyclohexane are preferable, and are curable and storage stable. Is excellent. In particular, those obtained from MIPK or MIBK and NBDA are preferred from the viewpoints of reactivity with urethane prepolymer, adhesion, storage stability, and water resistance. Ketimines can be used alone or in combination of two or more.

  The amount of ketimine added is 0.8 to 1.4 equivalents, preferably 0.9 to 1.1 equivalents, based on the isocyanate groups in the urethane prepolymer. Here, the equivalent means a molar ratio of ketimine groups to isocyanate groups in the urethane prepolymer. If the ketimine compounding amount is less than 0.8 equivalent or exceeds 1.4 equivalent, the curing of the urethane prepolymer becomes incomplete and the adhesive strength is insufficient.

  The tire label adhesive composition of the present invention is a two-part adhesive composed of the above-mentioned urethane prepolymer and ketimine, which cures at room temperature and has a high curing rate. Further, since it does not contain volatile organic compounds such as toluene and xylene, it is preferable from the viewpoint of environmental protection, and it is suitable for the user to stick the tire label on the surface of the sidewall part.

  When the tire label adhesive composition is mainly composed of a urethane prepolymer composed of tetramethylxylylene diisocyanate (TMXDI) and a polyol, it can be used as a one-component moisture-curable adhesive. In TMXDI, ketimine is difficult to react directly because its isocyanate group is sterically hindered by a methyl group. On the other hand, the primary amine hydrolyzed by ketimine reacts with the isocyanate group of TMXDI. Therefore, when the urethane prepolymer is made of TMXDI, ketimine can act as a moisture curing type curing agent.

  In this invention, a polyisocyanate oligomer can be mix | blended as an arbitrary component. By mix | blending a polyisocyanate oligomer, the adhesive strength of a tire label and a tire sidewall part surface can be made high. The polyisocyanate oligomer is a dimer or trimer of a polyisocyanate monomer, and may be a trimer.

  Although it does not restrict | limit especially as a polyisocyanate monomer, Hexamethylene diisocyanate (HDI), TDI, IPDI etc. can be illustrated.

  The polyisocyanate monomer trimer is preferably in the form of a biuret or isocyanurate. The polyisocyanate oligomer is preferably an HDI biuret, HDI, TDI, IPDI, or TMXDI isocyanurate. Among them, the chain biuret body tends to have a lower modulus than the cyclic isocyanurate body, and the HDI biuret body is more preferable.

  The compounding quantity of a polyisocyanate oligomer is 0-40 weight part with respect to 100 weight part of urethane prepolymers. If the blending amount of the polyisocyanate oligomer exceeds 40 parts by weight, the cured adhesive composition becomes too hard, so that it is difficult to follow the deformation of the sidewall part during running of the tire, and peeling easily occurs. Durability deteriorates. Moreover, when mix | blending a polyisocyanate oligomer, it is good to mix | blend preferably 10 weight part or more, and can make adhesive strength still higher.

  In addition, it can be used as a one-pack type adhesive composition by comprising a urethane prepolymer with tetramethylxylylene diisocyanate (TMXDI) and a polyol. At this time, as an optional polyisocyanate oligomer, a trimethylpropanol (TMP) adduct of TMXDI is preferable. The blending amount is preferably 0 to 40 parts by weight with respect to 100 parts by weight of the TMXDI prepolymer. When blending a polyisocyanate oligomer other than the TMXDI oligomer, the amount is preferably 10 parts by weight or less with respect to 100 parts by weight of the TMXDI prepolymer. When the amount exceeds 10 parts by weight, the viscosity increases with time due to reaction with ketimine in the system when a one-part adhesive composition is formed.

  The tire label adhesive composition may contain other compounding agents as long as the object of the present invention is not impaired. Examples of the compounding agent include a curing catalyst, a filler, a plasticizer, an antioxidant, an anti-aging agent, an inorganic pigment, an organic pigment, an adhesion imparting agent, a flame retardant, a dehydrating agent, a solvent, a silane coupling agent, and a thixotropy imparting agent. And antistatic agents. The amount of the compounding agent is not particularly limited, and an amount that can be generally used in the urethane-based adhesive composition can be blended.

  The adhesive composition for tire labels of the present invention can be suitably used when the tire label is attached to the surface of the sidewall portion. In this way, pneumatic tires with tire labels attached to the tire sidewalls not only have high static adhesion to the tire labels, but also have a dynamic durability that is difficult to peel off even when subjected to repeated large deformations during tire running. High nature. The type of pneumatic tire is not particularly limited, but passenger tires, truck / bus tires, and racing tires are suitable.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further, the scope of the present invention is not limited to these Examples.

  As the two-component adhesive, the main agent (urethane prepolymer) and the curing agents A to E were prepared by the following methods, and each curing agent was blended so as to be equivalent to the main agent shown in Tables 1 and 2. Sixteen types of two-component adhesive compositions (Examples 1 to 12, Comparative Examples 1 to 4) were obtained. In addition, two types of one-component adhesive compositions in which the main agent (TMXDI prepolymer) and ketimine A were prepared by the following methods as the one-component adhesive were formulated so as to have the compositions shown in Table 3 were used. (Examples 13 and 14) were prepared. As Comparative Example 5, a solvent-based chloroprene rubber adhesive (A-862-B manufactured by Yokohama Rubber Co., Ltd.) was used.

  The 19 kinds of obtained adhesive compositions were evaluated for pot life, peel strength, flexibility, 20% elongation stress and tensile elongation at break according to the following methods. In addition, since the adhesive composition of Comparative Example 4 had a very short pot life and was difficult to apply, a predetermined test piece for evaluation could not be prepared. Since Comparative Example 5 was a solvent system, it was difficult to apply a thick coating, and a tensile test specimen (dumbbell) could not be produced under the same conditions.

  Moreover, 18 types of adhesive compositions (Examples 1-14, Comparative Examples 1-3, 5) except the comparative example 4 were used, and the tire label of FIG. 1 was made into tire size 185 / like FIG. A pneumatic tire stuck to two locations on the sidewall surface of the 60R14 tire was produced. The base material layer of the tire label was composed of chloroprene rubber, and the rubber on the sidewall surface was composed of a rubber composition having the composition shown in Table 5. A drum running test of a pneumatic tire with a tire label attached was performed by the following method.

1. Preparation of main agent As shown in Tables 1 and 2, the main component of the two-part adhesive composition is an XDI prepolymer or TDI prepolymer prepared by the following method as a urethane prepolymer. A main agent was prepared by mixing a predetermined amount of an agent, calcium carbonate, and silica. In addition, as shown in Table 3, the one-component adhesive composition was prepared using the TMXDI prepolymer prepared by the following method as a urethane prepolymer, and the HDI biuret, TMXDI adduct, silane coupling agent, calcium carbonate, silica A predetermined amount of ketimine A described later was mixed to prepare a one-pack type adhesive composition.

XDI prepolymer Polyol compound consisting of 20 g of polypropylene ether triol (G-3000 manufactured by Asahi Glass Co., Ltd., number average molecular weight Mn3000) and 80 g of polypropylene ether diol (D-2000 manufactured by Asahi Glass Co., Ltd., number average molecular weight Mn2000) is converted into xylylene diisocyanate (XDI). And an NCO / OH molar ratio of 2.0 with Takenate 500 manufactured by Mitsui Chemicals Polyurethane Co., Ltd., and reacted in a nitrogen stream at 80 ° C. with stirring for 8 hours to obtain an XDI prepolymer.

A TDI prepolymer was prepared under the same conditions as the above XDI prepolymer except that the TDI prepolymer XDI was changed to tolylene diisocyanate (TDI, Cosmonate T-80 manufactured by Mitsui Chemicals Polyurethanes).

TMXDI prepolymer Same as the above XDI prepolymer except that XDI was changed to TMXDI (Cytech) and reacted in the presence of a tin catalyst (dibutyltin dilaurate, Neostan U-100 made by Nitto Kasei). The TMXDI prepolymer was obtained under the following conditions.

2. Preparation of Curing Agents A to E As shown in Table 4, five types of curing agents (curing agents A to E) with different types of ketones and polyamines were prepared. Ketimines A to D were prepared by the following method.

Ketimine A
100 g of norbornanediamine (NBDA, manufactured by Mitsui Chemicals) and 200 g of methyl isopropyl ketone (MIPK) are placed in a flask together with 200 g of toluene and reacted for 20 hours while removing the water produced by azeotropic distillation, and MIPK-NBDA-MIPK. Ketimine A consisting of

Ketimine B
Ketimine B composed of MIPK-HMDA-MIPK was obtained under the same preparation conditions as the above ketimine A, except that NBDA was changed to 100 g of hexamethylenediamine (HMDA, manufactured by Wako Pure Chemical Industries, Ltd.).

Ketimine C
Ketimine C composed of DIBK-HMDA-DIBK was obtained under the same preparation conditions as ketimine B described above except that MIPK was changed to 200 g of diisobutyl ketone (DIBK, manufactured by Wako Pure Chemical Industries, Ltd.).

Ketimine D
Ketimine D consisting of MEK-NBDA-MEK was obtained under the same preparation conditions as ketimin A described above except that MIPK was changed to 200 g of methyl ethyl ketone (MEK, manufactured by Wako Pure Chemical Industries, Ltd.).

Evaluation of tire label adhesive composition Pot life The time [min] from when the obtained adhesive composition was applied onto a Teflon (registered trademark) sheet until the surface was covered was measured, and the results obtained are shown in Tables 1, 2 and 3. It was. In the two-part adhesive composition, the main agent and the curing agent were uniformly mixed immediately before coating.

2. Peel strength A chloroprene rubber sheet having a length of 200 mm, a width of 150 mm, and a thickness of 2 mm and a natural rubber sheet having the same size were prepared as adherends. Each adhesive composition was applied to a sheet of chloroprene rubber so as to be 0.2 kg / m ^2, and a natural rubber sheet was bonded thereto to obtain an adhesive. The obtained adhesive was cured by curing for 7 days under conditions of 23 ° C. and 55% RH.
Next, based on the T-type peel test method of JIS K6854-3, the peeled force (unit: N / 25 mm) under the condition of a tensile speed of 100 mm / min is measured and the average value is obtained for the cured adhesive body. This value was taken as the peel strength, and the results are shown in Tables 1, 2 and 3.

3. Stress at 20% elongation, elongation at break at break, and flexibility The adhesive composition obtained by mixing the obtained main agent and curing agent was applied on a Teflon (registered trademark) sheet and cured at 20 ° C. and 55% RH for 7 days. did. Thereafter, a dumbbell-shaped No. 3 test piece having a thickness of 2 mm was cut out from the cured product. Using each dumbbell-shaped No. 3 test piece, a tensile test (tensile speed: 500 mm / min) was conducted according to JIS K6251, and the stress at 20% elongation [N / mm ² ] and tensile elongation at break [%] Was measured. The obtained results are shown in Tables 1, 2 and 3, respectively.
A rubber composition having the composition shown in Table 5 was used to prepare a vulcanized sheet having a thickness of 2 mm, and a dumbbell-shaped No. 3 test piece was cut out. Using this test piece, a tensile test (tensile speed: 500 mm / min) was performed according to JIS K6251 to measure a stress [N / mm ² ] at 20% elongation. The stress at 20% elongation of the rubber constituting the surface of the sidewall portion was 0.40 N / mm ² .
Also, the stress in the 1-50% elongation region during the tensile test was compared between the adhesive composition and the rubber constituting the sidewall surface, and the flexibility was evaluated according to the following criteria. The results obtained are shown in Table 1. , 2 and 3.
○: The stress of the adhesive composition is not more than 1.5 times the stress of the rubber of the sidewall portion in the entire region of 1 to 50% elongation. Is more than 1.5 times the stress of rubber in the sidewall

4). Drum running test Fifteen types of tires with tire labels attached are mounted on a rim (5.5 JJ x R14), air pressure is 200 kPa, an indoor drum tester (drum diameter 1707 mm) compliant with JIS D4230, and JISMA specified load Then, a drum running test of 3000 km was performed under the condition of a speed of 80 km / h, and the running distance until the tire label peeled was measured. When the tire label did not peel off after running at 3000 km, it was set as “over 3000 km” and the results are shown in Tables 1, 2 and 3.

The types of raw materials used in Tables 1, 2, and 3 are shown below.
HDI Nurate: HDI isocyanurate, Death Module N3300 manufactured by Sumika Bayer
HDI biuret: HDI biuret body, Death Module N3200 manufactured by Sumika Bayer
TMXDI adduct: TMXDI trimethyl propanol (TMP) adduct body, Cytec 3174
Silane coupling agent: γ-glycidoxypropyltrimethoxysilane, Shin-Etsu Chemical KBM403
Octyl acid: Wako Pure Chemical Industries calcium carbonate: Maruo Calcium Calfine 200
Silica: Nippon Aerosil Co., Ltd. R972

In Table 4, the types of raw materials used are shown below.
Carbon black: Shin Nikka Carbon # 20Y
The same calcium carbonate and silica as in Tables 1, 2, and 3 were used.

In addition, the kind of raw material used in Table 5 is shown below.
NR: natural rubber, RSS # 1
BR: butadiene rubber, Nipol BR1220 manufactured by Nippon Zeon
Carbon black: HTC 100 manufactured by Chubu Carbon Co.
Zinc Oxide: Toho Zinc Co., Ltd., Silver Zinc Hana, Stearic Acid: Industrial Stearic Acid, Kao Soap Co., Ltd. Lunac YA
Anti-aging agent 1: Nocrack 6C manufactured by Ouchi Shinsei Chemical Co., Ltd.
Antiaging agent 2: Nocrack 224 manufactured by Ouchi Shinsei Chemical Co., Ltd.
Wax: Microcrystalline wax, Sannok oil manufactured by Ouchi Shinsei Chemical Co., Ltd .: Aromatic process oil, KOMOlex 300 manufactured by Nippon Oil Corporation
Vulcanization accelerator: NOCELLER DM manufactured by Ouchi Shinsei Chemical
Sulfur: Powder sulfur produced by Karuizawa Refinery

(A) (B) is an example of the tire label stuck using the adhesive composition of this invention, (A) is a plain view, (B) is a side view. 1 is a side view of a tire in which a tire label is attached to a surface of a sidewall portion of a pneumatic tire.

Explanation of symbols

1 Tire label T Pneumatic tire T1 Side wall part Ta Side wall part surface

Claims (3)

  A tire label adhesive composition for adhering a tire label to the surface of a sidewall portion of a tire, the adhesive composition having a urethane prepolymer having a plurality of isocyanate group terminals in the molecule as a main component, In addition to containing 0.8 to 1.4 equivalents of ketimine relative to the isocyanate group, 0 to 40 parts by weight of polyisocyanate oligomer is blended with 100 parts by weight of the urethane prepolymer, and the adhesive composition after curing An adhesive composition for tire labels, wherein the stress at the time of tensile deformation of 1% to 50% of the article is not more than 1.5 times the stress when the amount of tensile deformation of the rubber on the sidewall portion surface is made the same.   The tire label adhesive composition according to claim 1, wherein the ketimine is a reaction product of a polyamine and a ketone having a side chain at the α-position carbon atom.   A pneumatic tire in which a tire label is bonded to a sidewall portion of the tire using the tire label adhesive composition according to claim 1.

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