JP3944782B2 - Aqueous polyurethane resin dispersion, aqueous adhesive containing the same, and aqueous primer coating agent - Google Patents

Description

  The present invention is excellent in adhesiveness, heat resistance, application workability, etc., and is based on water-based adhesive or water-based primer coating on various substrates such as plastic, leather, rubber, foam, textiles, paper, glass and metal. The present invention relates to an aqueous polyurethane resin dispersion applicable as an agent.

  Conventionally, so-called solvent-based adhesives containing organic solvents have been widely used for bonding substrates such as plastics such as polyvinyl chloride (PVC), leather, rubber, resin foam, textiles, glass and metal. Has been used. Also, for example, when a base material that easily penetrates the adhesive, such as leather or textiles, is used, even if the adhesive is applied directly to the base material, the base material penetrates and a sufficient adhesive layer is provided. Therefore, in order to prevent resin penetration, an adhesive is used after applying a primer coating agent and applying a sealing treatment in advance.

  In recent years, from the viewpoint of environmental harmony, the solvent-based adhesive or solvent-based primer coating agent is changed to an aqueous adhesive or water-based primer coating agent, particularly an adhesive or primer coating agent using a polyurethane resin aqueous solution or water dispersion. Alternatives are being developed. When bonding using such water-based adhesives, processing is performed under different conditions such as various production lines and processing temperatures, etc., but high bonding strength can be exhibited immediately after bonding and over time in each processing condition. is important.

  As an adhesion processing method using an adhesive containing the organic solvent and water, dry lamination and wet lamination are typical methods, but because efficient solvent removal by drying using a heat source is possible, In recent years, dry lamination has become the mainstream of adhesive processing centering on solvent-based adhesives.

  The dry lamination is a method in which an adhesive is applied to a base material, a drying process is performed to remove an organic solvent and water contained in the adhesive, and then the base material is bonded. The adhesive used for the dry lamination is required to sufficiently melt the adhesive and obtain high adhesive strength particularly in the drying step. Furthermore, in the case of a water-based adhesive, the slow drying rate of water becomes a problem, so it is essential to increase the concentration of the adhesive.

  In addition, when a substrate having low heat resistance such as EVA foam is used in dry lamination, for example, the drying temperature needs to be about 50 to 70 ° C. in order to prevent thermal deformation of the substrate. is there. In this case, it is extremely important that the adhesive sufficiently melts even at such a low drying temperature.

For example, in the field of shoe bonding processing, the demand for water-based primer coating agents and adhesives has increased greatly in recent years, and adhesives that satisfy the above conditions are strongly desired by the industry. The current situation is not yet completed.
In shoe bonding processing, the shape of the shoe and the material of the base material used are diverse, so in various bonding processes represented by the sole (shoe sole) and midsole (midsole), manual application using a brush is used. Work is mainstream. Furthermore, dry lamination is generally used from the viewpoint of the material of the base material used for shoes and the production efficiency.

In this case, a sufficient tack time ("bondable time") that does not lose adhesiveness after applying the adhesive to the various base materials of the shoes and before bonding and crimping is performed. It is important to have excellent coating workability such as brush coating properties.
In addition, it is extremely important to have high adhesive strength immediately after bonding, that is, to develop initial adhesiveness. If the initial adhesiveness is insufficient, for example, a substrate having a curved shape has a problem that even if the substrates are bonded together, it cannot withstand the restoring force of the substrate and peeling occurs at the bonded portion.

  Furthermore, even when the shoes that have been completed through the bonding process are exposed to high temperature conditions during transportation or storage, durability such as heat resistance and hydrolysis resistance that can maintain high bonding strength is also required. .

As described above, in the field of shoe bonding processing, the coating workability is excellent, the tack time is appropriate, and the adhesive is sufficiently melted even under low temperature drying conditions of about 50 to 70 ° C. There is a demand for an adhesive having a high level of all required properties such as high adhesive strength and excellent heat resistance.
In particular, meltability at a low temperature and obtaining high adhesive strength immediately after bonding (initial adhesiveness) are incompatible with the design of the adhesive, and it is extremely difficult to achieve both properties.

For example, an isocyanate group-terminated urethane prepolymer, which has an ethylene oxide unit, has a hydroxyl value of 10 to 130, and uses a hydrophilic urethane prepolymer having an isocyanate group at the end as a dispersant. A method for producing an aqueous polyurethane resin dispersion comprising an agent, water and the like is disclosed (Patent Document 1).
However, the polyurethane resin aqueous dispersion obtained by such a production method contains ethylene oxide units in a large amount of 40 to 98% by weight in the hydrophilic urethane prepolymer. Therefore, when an attempt is made to use the polyurethane resin aqueous dispersion as an aqueous adhesive, the aqueous adhesive will increase in viscosity even if the resin solid content is increased to about 40% by weight in order to obtain a desired adhesive strength. The coating workability was remarkably deteriorated and could not be put to practical use.
Furthermore, the decrease in water-resistant peel strength after the adhesive processing becomes remarkable, and the water resistance and adhesive strength required as a water-based adhesive cannot be sufficiently satisfied.

Also, a polyurethane characterized in that a urethane prepolymer having an isocyanate group at a substantially water-insoluble terminal is dispersed in water in the presence of a self-emulsifiable water-soluble polyurethane, and then a chain extender is added and reacted. A method for producing an aqueous dispersion is disclosed (Patent Document 2).
However, even when polyurethane aqueous dispersions obtained by various specific production methods disclosed in this document are applied to dry lamination adhesives, both have insufficient adhesive strength immediately after bonding, and have a curved shape. In the case of a substrate or the like having a problem, there arises a problem that the bonded portion is peeled off.

  As described above, water-based adhesives and water-based primer coating agents that have many required characteristics such as coating workability, appropriate tack time, low-temperature meltability, initial adhesiveness, and durability at a high level are still available. It is not completed.

JP-A-58-38823 (claim “1st page claims“ Claim 1 ”to page 5 left column bottom 14th line)” Japanese Patent Application Laid-Open No. 2-20511 (Claim 1 claim on page 1 "Claim 1" to page 5, left column, bottom line 12)

  The purpose of the present invention is excellent in the workability of application to various substrates, in particular, the adhesive sufficiently melts even under low temperature drying conditions of about 50 to 70 ° C., and high adhesive strength is obtained immediately after bonding after drying, Furthermore, it is providing the polyurethane resin aqueous dispersion which can obtain the water-based adhesive and water-based primer coating agent which are excellent also in the heat resistance after an adhesive process.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that an aqueous dispersion having dispersed particles containing a self-emulsifying polyurethane resin and a hydrophobic resin having an outflow start temperature of 60 ° C. or lower is an adhesive. As a result, it is found that the adhesive is plasticized by a hydrophobic resin having a low outflow start temperature, which can be applied to a drying process under a relatively low temperature condition, so that rapid melting of the adhesive is promoted. It was.

  In addition, when imparting hydrophilicity for imparting water dispersibility to the polyurethane resin, by introducing an anionic group, the concentration of the aqueous dispersion is increased for the purpose of obtaining good low-temperature drying properties and adhesive strength. In addition, the present inventors have found that excellent coating workability can be obtained without extremely thickening as in the case of introducing a nonionic group.

  By the above-mentioned method, it was possible to improve the meltability of the adhesive under low temperature drying conditions. However, along with this, the problem was that the adhesive strength immediately after bonding the substrates was lowered. As a result of further studies, it has been found that the crystallization speed of the hydrophobic resin greatly affects the adhesive strength immediately after bonding the substrates. That is, by selecting a resin having an outflow start temperature of 60 ° C. or lower and crystallizing at a high temperature when the hydrophobic resin in a molten state is cooled, the hydrophilic polyurethane resin and the hydrophobic resin are selected. Since the crystallization speed of the composite with the adhesive resin itself is improved, it becomes possible to develop a high adhesive strength immediately after bonding, and to find that excellent initial adhesiveness can be obtained, thereby completing the present invention. It came to.

  That is, the present invention relates to a self-emulsifying polyurethane resin (A) having an anionic group, and a hydrophobic resin having an outflow start temperature (X) of 60 ° C. or lower and a crystallization temperature (Y) of 0 to 50 ° C. Dispersed particles containing (B) and an aqueous polyurethane resin dispersion comprising an aqueous medium are provided.

Preferably, the content of the ionic group of the hydrophobic resin (B) is 50 mmol / kg or less and the ethylene oxide [(CH ₂ CH ₂ O) _n ; n ≧ 5] structural unit having 5 or more repeating units. The amount is 5% by weight or less.

  The present invention also provides an aqueous adhesive comprising the polyurethane resin aqueous dispersion.

  Furthermore, the present invention provides an aqueous primer coating agent comprising the polyurethane resin aqueous dispersion.

The technical term “outflow start temperature (X)” as used in the present invention is a sample of a dry film of a resin to be measured as a sample, held at 40 ° C. for 10 minutes using a flow tester, and then a die 1 mmφ × 1mm long, 10kg load, 3 ° C / min. The temperature rises at a rate of 3 ° C / min. After the piston is slightly lifted due to thermal expansion of the sample, the outflow start temperature (° C) starts to descend clearly again. Means.
In addition, in this specification, the outflow start temperature (X) measured using CFT-500D CAPILLARY RHEOMETER by Shimadzu Corporation was adopted as a flow tester.

In addition, the technical term “crystallization temperature (Y)” in the present invention is measured under the following conditions using a differential scanning calorimeter (DSC) with a dry film of a resin to be measured as a sample. The temperature at the top of the exothermic peak that appears during the temperature lowering process is meant.
[Measurement conditions of differential scanning calorimeter]
Temperature raising process (0 ° C → 60 ° C: temperature rising rate 3 ° C / min)
Temperature drop process (60 ° C → -20 ° C: temperature drop rate 3 ° C / min)
* Holding time from the temperature raising step to the temperature lowering step = within 1 minute In this specification, the crystallization temperature (Y) measured using DSC Q100 manufactured by TA Instruments Co., Ltd. as a differential scanning calorimeter )It was adopted.

  According to the present invention, it is excellent in coating workability for various substrates, melts sufficiently even under low temperature drying conditions, has excellent adhesion immediately after bonding the substrates after drying and after aging, and also has heat resistance. An aqueous polyurethane resin dispersion capable of obtaining an excellent aqueous adhesive can be provided.

  The aqueous polyurethane resin dispersion of the present invention comprises a self-emulsifying polyurethane resin (A) having an anionic group, an outflow start temperature (X) of 60 ° C. or less, and a crystallization temperature (Y) of 0 to 50 ° C. It contains dispersed particles containing the hydrophobic resin (B) and an aqueous medium.

  It is better not to form a chemical bond between the polyurethane resin (A) and the hydrophobic resin (B) contained in the dispersed particles, and the adhesive is sufficiently melted even under the low-temperature drying conditions achieved by the present invention. In addition, it is preferable because the effect of excellent initial adhesiveness can be further enhanced.

  Next, the self-emulsifying polyurethane resin (A) having an anionic group in the molecule used in the present invention will be described.

The polyurethane resin (A) used in the present invention has an anionic group represented by a carboxyl group or a sulfonic acid group or a salt thereof as a hydrophilic group for imparting water dispersibility in the molecule.
The content of the anionic group contained in the polyurethane resin (A) has a strong correlation with the particle diameter when the polyurethane resin (A) is made into an aqueous dispersion, and the content of the anionic group is The polyurethane resin (A) is preferably prepared so as to be in the range of 50 to 1000 mmol / kg. Within such a range, good dispersion stability of the particles can be obtained without impairing water resistance and stable without causing aggregation or precipitation even when the dispersed particles are stored for a long period of time.

As a method for producing such a self-emulsifiable polyurethane resin (A) having an anionic group, a known method can be employed.
For example, (i) a polyurethane resin (A) having an anionic group by reacting a polyol and a polyisocyanate having an anionic group represented by a carboxyl group or a sulfonic acid group or a salt thereof as an essential component How to manufacture,

(ii) In the above (i), a prepolymer containing an isocyanate group is produced by reacting a polyol and a polyisocyanate under the condition that the isocyanate group of the polyisocyanate is excessive with respect to the hydroxyl group of the polyol. A method for producing a polyurethane resin (A) having an anionic group by reacting a polyamine or the like to cause chain elongation (high molecular weight);

(iii) A prepolymer containing an isocyanate group by using a polyol having no anionic group and reacting the polyol with the polyisocyanate under the condition that the isocyanate group of the polyisocyanate is excessive with respect to the hydroxyl group of the polyol. A polyurethane resin having an anionic group (A) by reacting a polyamine having an anionic group such as diaminosulfonate and causing chain elongation (high molecular weight),

(iv) For example, a method of producing a polyurethane resin (A) having an anionic group by reacting a polyamine having an anionic group such as diaminosulfonate with a polyisocyanate can be employed.

  Moreover, when a polyurethane resin (A) has a carboxyl group and / or a sulfonic acid group as an anionic group, favorable water dispersibility can be provided by neutralizing some or all of them. At that time, for example, at least one neutralizing agent selected from organic amines such as ammonia, triethylamine, pyridine, morpholine, alkanolamines such as monoethanolamine, and metal base compounds including Na, K, Li, Ca, etc. Can be used. The neutralization rate is preferably neutralizer / anionic group = 0.5 to 3.0 (molar ratio), more preferably neutralizer / anionic group = 0.9 to 2.0 (molar ratio). It is desirable to use in the range. If it is this range, the stable self-emulsification property can be provided, without impairing water resistance.

  In the above method (i) or (ii), as a typical polyol containing a carboxyl group that can be used as a polyol containing an anionic group, 2,2′-dimethylolpropionic acid, 2,2′-dimethylolbutanoic acid, 2,2′-dimethylolbutyric acid, 2,2′-dimethylolvaleric acid and the like can be mentioned. Also, carboxyl group-containing polyester polyols obtained by reacting these carboxyl group-containing polyols and various polycarboxylic acids can be used.

  In the method (i) or (ii), typical examples of polyols containing sulfonic acid groups that can be used as polyols containing anionic groups include 5-sulfoisophthalic acid, sulfo Dicarboxylic acid such as terephthalic acid, 4-sulfophthalic acid, 5 [4-sulfophenoxy] isophthalic acid, and / or metal ions such as Na, K, Li, and Ca, ammonia, diethylamine, and triethylamine Examples include polyester polyols containing aromatic sulfonic acid groups and / or salts thereof obtained by reacting at least one sulfonate with various polyols.

  In addition to the polyol containing the anionic group, the ethylene oxide repeating unit is contained at least 30% by weight, and the number average molecular weight containing at least one active hydrogen atom-containing group is 300 to 10,000. Nonionic group-containing polyols such as polyalkylene glycol can be used in combination. As nonionic group content, it is preferable to prepare so that it may become 10 weight% or less of the whole polyurethane resin (A). Within such a range, good water dispersion stability can be obtained without impairing water resistance.

  When the polyurethane resin (A) used in the present invention is produced, a high molecular weight polyol or a low molecular weight polyol other than the polyol containing the anionic group may be used.

The high molecular weight polyol that can be used in the production of the polyurethane resin (A) preferably has a hydroxyl value in the range of 10 to 350, more preferably a hydroxyl value in the range of 20 to 300.
The “hydroxyl value” referred to here is the number of mg of potassium hydroxide required to neutralize acetic acid bonded to a hydroxyl group when 1 g of a sample is acetylated.

  Examples of the high molecular weight polyol include polyester polyol, polyether polyol, polycarbonate polyol and the like. These high molecular weight polyols may be used alone, in combination of two or more kinds, or may be used as a copolymer. In particular, it is preferable to use polyester polyol as a main component from the viewpoint of excellent adhesion to a wide range of substrates and cost.

  The polyester polyol can be produced by reacting a known polycarboxylic acid or various reactive derivatives thereof with a known low molecular weight polyol having a molecular weight of 300 or less by a known method.

Examples of the polycarboxylic acid include aliphatic dicarboxylic acids such as succinic acid, succinic anhydride, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dimer acid, maleic anhydride, fumaric acid, and the like. -Cycloaliphatic dicarboxylic acids such as cyclohexanedicarboxylic acid, polycarboxylic acids such as trimellitic acid, pyromellitic acid, cyclohexanetricarboxylic acid and the like or their anhydride or ester-forming derivatives as polyfunctional components, terephthalic acid, isophthalic acid, Phthalic acid, 1,4-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, naphthalic acid, biphenyldicarboxylic acid, 1,2-bis (phenoxy) ethane-p, p'-dicarboxylic acid Aromatic dicarboxylic acids such as acids and their acid anhydrides or esters Formable derivatives, aromatic hydroxycarboxylic acids such as p-hydroxybenzoic acid and their ester-forming derivatives can be used. These polycarboxylic acids may be used alone or in combination of two or more.
Examples of cyclic esters that can be used include ε-caprolactone and γ-valerolactone.

  On the other hand, examples of low molecular weight polyols that can be used in producing the polyester polyol include ethylene glycol, propylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1,5 -Pentanediol, 1,6-hexanediol, neopentyl glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, polyethylene glycol, 3-methyl-1,5-pentanediol, 2-butyl Aliphatic diols such as 2-ethyl 1,3-propanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, alicyclic diols such as hydrogenated bisphenol A, bisphenol A, and hydride Quinones, polyols bishydroxyethoxybenzene and their alkylene oxide adducts of glycerin as also multifunctional components, trimethylolpropane, polyols such as pentaerythritol, and the like. These low molecular weight polyols may be used alone or in combination of two or more.

Examples of the polyether polyol that can be used in the production of the polyurethane resin (A) include, for example, ethylene oxide, propylene oxide, butylene oxide, styrene in the presence of a compound having an active hydrogen atom (reactive hydrogen atom). Examples thereof include polymers obtained by ring-opening polymerization of various three-membered or four-membered ether compounds such as oxide, tetrahydrofuran or epichlorohydrin alone or a mixture of two or more thereof.
Specific examples include polyethylene glycol, polypropylene glycol, and polytetramethylene glycol. These may be used alone or in combination of two or more.
Further, a polyether monool partially blocked with a monoalcohol such as methanol or butanol may be used within a range that does not inhibit the increase in the molecular weight.

  Examples of the polycarbonate polyol that can be used in the production of the polyurethane resin (A) include 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, diethylene glycol, polyethylene glycol, polypropylene glycol, and polytetramethylene. Examples thereof include a reaction product of a diol such as glycol with a dialkyl carbonate represented by dimethyl carbonate or the like, or a cyclic carbonate represented by ethylene carbonate or the like. These polycarbonate polyols may be used alone or in combination of two or more.

Moreover, as a low molecular weight polyol which can be used when manufacturing the said polyurethane resin (A), the thing similar to what was described as a specific example of the low molecular weight polyol which can be used when manufacturing the said polyester polyol is used. Can be mentioned.
Furthermore, monoalcohol may be used in combination as long as the cohesive force of the polyurethane resin (A) is not inhibited. Illustrative examples of monoalcohols include monoalcohols having a molecular weight of 300 or less, such as methanol, ethanol, n-butanol, isopropanol, and n-hexanol.

  As described above, in producing the polyurethane resin (A), a prepolymer containing an isocyanate group is produced in advance, and this is reacted with a polyamine to cause chain elongation to increase the molecular weight. Alternatively, a polyamine and a polyisocyanate are combined. Although the method of making it react can be employ | adopted, the polyamine of molecular weight 300 or less which is illustrated below as a polyamine at this time can be used.

  1,2-diaminoethane, 1,2- or 1,3-diaminopropane, 1,2- or 1,3- or 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diamino Hexane, piperazine, N, N′-bis- (2-aminoethyl) piperazine, 1-amino-3-aminomethyl-3,5,5-trimethyl-cyclohexane (isophoronediamine), bis- (4-aminocyclohexyl) Diamines such as methane, bis- (4-amino-3-butylcyclohexyl) methane, 1,2-, 1,3- or 1,4-diaminocyclohexane or 1,3-diaminopropane, diethylenetriamine, triethylenetetramine, etc. Hydrazine derivatives such as hydrazine or adipic acid dihydrazide, N- (2-sulfoethyl) ester Metal salts of diamine and 2-(beta-amino alkyl - amino propionamide) - can be used diaminosulphonate such as alkane sulfonic acid salts.

  Furthermore, amino alcohol having both an amino group and an alcoholic hydroxyl group in the molecule can also be used. For example, ethanolamine, N-methyldiethanolamine, propanolamine, N-methyldiisopropanolamine, N-ethyldiethyleneamine, N-ethyldiisopropanolamine, aminoethylethanolamine, diethanolamine and the like can be mentioned.

As the polyamine, it is preferable to use one having two or more functional groups (amino groups) in order not to impair durability, and in this case, a polyamine having two or more functional groups may be used alone, Alternatively, two or more types may be used in combination, and the average number of functional groups may be 2 or more.
When the prepolymer containing an isocyanate group is chain-extended to increase the molecular weight, the amount of polyamine used is preferably 1.9 equivalent ratio or less, more preferably 0.5- 1.9 equivalence ratio, most preferably in the range of 0.6 to 1.0 equivalent ratio. If chain extension is performed using a polyamine having a molecular weight of 300 or less within such a range, the molecular weight can be increased within a suitable range, and excellent durability and light resistance can be exhibited. However, the case where polyamine is not used may be used.

In the method for producing the polyurethane resin (A), a known polyisocyanate can be used.
For example, 1,4-tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate, 1,12-dodecamethylene diisocyanate, cyclohexane-1,3- or 1,4-diisocyanate, 1-isocyanato-3-isocyanatomethyl-3 , 5,5-trimethylcyclohexane (also known as isophorone diisocyanate; IPDI), bis- (4-isocyanatocyclohexyl) methane (also known as hydrogenated MDI), 2- or 4-isocyanatocyclohexyl-2'-isocyanatocyclohexylmethane, , 3- or 1,4-bis- (isocyanatomethyl) -cyclohexane, bis- (4-isocyanato-3-methylcyclohexyl) methane, 1,3- or 1,4-α, α, α'α'- Tetramethylxylylene diisocyanate 2,4- or 2,6-diisocyanatotoluene, 2,2'-, 2,4'- or 4,4'-diisocyanatodiphenylmethane (MDI), 1,5-naphthalene diisocyanate, p- or m -Phenylene diisocyanate, xylylene diisocyanate or diphenyl-4,4'-diisocyanate.
Among these, the use of aromatic diisocyanate is desirable particularly when considering the mechanical strength and the like, and when considering the durability and light resistance, the aliphatic or cycloaliphatic diisocyanate compound is particularly desirable. Use is desirable.

  The isocyanate group content in the polyurethane resin (A) is preferably in the range of 8 to 30% by weight. Within such a range, the cohesive strength of the urethane molecules is in a suitable range, and high adhesive strength can be expressed.

Next, the hydrophobic resin (B) used in the present invention will be described.
The hydrophobic resin (B) has an outflow start temperature (X) of 60 ° C. or less and a crystallization temperature (Y) of 0 to 50 ° C. in an aqueous medium together with the self-emulsifying polyurethane resin (A). Constitutes the dispersed particles present in.

  Since the hydrophobic resin (B) has an outflow start temperature (X) of 60 ° C. or less, when the polyurethane resin aqueous dispersion of the present invention is used as an adhesive or an aqueous primer coating agent, a relatively low temperature condition ( For example, in the drying step at about 50 to 70 ° C., the adhesive is plasticized by the hydrophobic resin (B) having a low outflow start temperature (X), so that the adhesive can be rapidly melted. it can.

  Moreover, when the hydrophobic resin (B) has a crystallization temperature (Y) of 0 to 50 ° C., when the polyurethane resin aqueous dispersion of the present invention is used as an adhesive or an aqueous primer coating agent, the adhesive Or, after drying the substrate coated with the aqueous primer coating agent at a relatively low temperature condition (for example, about 50 to 70 ° C.) and then performing bonding, the resin crystallization speed is increased, High adhesive strength can be expressed immediately after bonding.

  Note that the temperature at which the resin is crystallized when the temperature is actually lowered from the molten state varies mainly depending on conditions such as the temperature drop rate. That is, even if the crystallization temperature (Y) of the hydrophobic resin (B) is not more than room temperature, the crystallization temperature (Y) is a temperature at which crystallization occurs under the specific measurement conditions described above, and is actually bonded. In the environment where the agent is used, sufficient crystallization can occur even at a temperature above room temperature.

The hydrophobic resin (B) used in the present invention is a resin which does not have a hydrophilic group or a hydrophilic structural unit or has a small content thereof. Specifically, 1) an ionic group Resin satisfying both conditions of content of 50 mmol / kg or less, 2) ethylene oxide [(CH ₂ CH ₂ O) _n ; n ≧ 5] structural unit content of 5% by weight or less It is preferable that
If these conditions are satisfied, the affinity with water will be low, and the water resistance of the polyurethane resin aqueous dispersion of the present invention will not be reduced.

The hydrophobic resin (B) preferably has a number average molecular weight in the range of 1000 to 20,000, and more preferably has a number average molecular weight in the range of 2,000 to 16,000.
If the number average molecular weight and the outflow start temperature (X) of the hydrophobic resin (B) are within the above ranges, the coating is sufficiently melted in the drying step under relatively low temperature conditions (for example, about 50 to 70 ° C.), In addition, the cohesive force of the resin can be moderately moderated, and an appropriate tack time, excellent adhesive strength and heat resistance can be obtained.

  In addition, the technical term “number average molecular weight (Mn)” used in the present specification is prepared using tetrahydrofuran (THF) as an eluent, measured by gel permeation chromatography (GPC), and using standard polystyrene. It means the value obtained from the calibration curve.

  As the hydrophobic resin (B) used in the present invention, a hydrophobic resin having an outflow start temperature (X) of 60 ° C. or less and a crystallization temperature (Y) of 0 to 50 ° C. can be used. In order to achieve the effects of the present invention more particularly, at least one substantially linear hydrophobic resin selected from the group consisting of aliphatic polyester resins, aliphatic polycarbonate resins, and polyurethane resins is used. It is preferable to use it.

  Among these, aliphatic polyester resin (B-PE) and polyurethane resin (B-PU) are preferable as hydrophobic resin (B), more preferably, from the viewpoint of particularly good adhesiveness and applicability to a wide range of uses. Can use the polyurethane resin (B-PU) alone, and when the polyurethane resin aqueous dispersion of the present invention is used as an adhesive or an aqueous primer coating agent, the highest cohesion can be obtained. This is preferable because high adhesive strength can be expressed.

  As the aliphatic polyester resin as the hydrophobic resin (B), at least one carboxylic acid (b-1) selected from linear aliphatic dicarboxylic acids having 2 to 10 carbon atoms and ε-caprolactone, A substantially linear aliphatic polyester resin (B-PE) obtained by reacting with a linear aliphatic diol (b-2) having 2 to 6 carbon atoms as an essential component by a known method. Is preferred.

Examples of the carboxylic acid (b-1) include succinic acid, succinic anhydride, adipic acid, pimelic acid, suberic acid, azelaic acid, and sebacic acid. In addition, ε-caprolactone can be used as the group dicarboxylic acid and cyclic ester. These carboxylic acids may be used alone or in combination of two or more.
The amount of the carboxylic acid (b-1) used is preferably 80 mol% or more, more preferably 90 mol% or more of the total polycarboxylic acid used when the polyester resin is produced. If it is this range, the crystallinity of aliphatic polyester resin (B-PE) will become suitable, and the adhesive physical property accompanying crystallization will be attained.

Examples of the diol (b-2) include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, diethylene glycol, triethylene glycol, tetra Aliphatic diols such as ethylene glycol can be used, and these may be used alone or in combination of two or more.
The amount of the diol (b-2) used is preferably 80 mol% or more, more preferably 90 mol% or more of the total polyol used when the polyester resin is produced. If it is this range, the crystallinity of aliphatic polyester resin (B-PE) will become suitable, and the improvement of the crystallization speed | rate will be attained.

Moreover, in order to control the molecular weight and outflow start temperature of the aliphatic polyester resin (B-PE), the use ratio of the carboxylic acid (b-1) and the diol (b-2) is changed to the carboxylic acid (b -1): Diol (b-2) = 1: 1.02 to 1: 1.3 diol excess system, or carboxylic acid (b-1): diol (b-2) = 1.02: 1 to 1 It is desirable to adjust by reacting in a 3: 1 carboxylic acid excess system. Also, molecular weight and onset of spillage by using monoalcohol having 1 to 20 carbon atoms and polyether monool blocked with monoalcohol having 1 to 20 carbon atoms during the production of aliphatic polyester resin (B-PE) The temperature can also be controlled.
Within such molecular weight and outflow start temperature range, the thermal meltability of the resin in the dispersed particles constituting the polyurethane resin aqueous dispersion of the present invention is enhanced, and the initial adhesiveness immediately after adhesion is improved, and further after bonding. Then, it is possible to improve the adhesive properties accompanying crystallization.

As the aliphatic polycarbonate resin as the hydrophobic resin (B), a linear aliphatic diol (b-3) having 2 to 6 carbon atoms and a dialkyl carbonate (b-4) represented by dimethyl carbonate, A substantially linear aliphatic polycarbonate resin (B-PC) having a hydroxyl value of 10 to 220, more preferably 20 to 150, which is obtained by a known method, is preferred.
In this case, as the linear aliphatic diol (b-3) having 2 to 6 carbon atoms, for example, ethylene glycol, 1,4-butanediol, 1,6-hexanediol and the like can be used.

  By reacting an excess amount of the linear aliphatic diol (b-3) with the dialkyl carbonate (b-4), an aliphatic polycarbonate resin (B-PC) having a hydroxyl group at the molecular end is obtained. Thus, the molecular weight and the outflow start temperature can be controlled. Within such a range, the heat melting property of the resin in the dispersed particles constituting the polyurethane resin aqueous dispersion of the present invention is improved, and the initial adhesiveness immediately after the adhesion is improved. The physical properties can be improved.

The polyurethane resin (B-PU) as the hydrophobic resin (B) used in the present invention comprises a linear aliphatic polyol (b-5) and a diisocyanate (b-6) as essential components by a known method. As a preferred example, a substantially linear polyurethane resin (B-PU) obtained by reacting by a known method is preferable.
As the linear aliphatic polyol (b-5), a linear aliphatic polyester polyol or a linear aliphatic polycarbonate resin (B-PC) having a hydroxyl group at the molecular end may be used. it can.

The linear aliphatic polyester polyol as the aliphatic polyol (b-5) is obtained by reacting the carboxylic acid (b-1) and the diol (b-2) as essential components by a known method. The resulting polyester polyol can be used.
At this time, the amount of the carboxylic acid (b-1) used is preferably 80 mol% or more of the total polycarboxylic acid used in producing the linear aliphatic polyester polyol, and is 90 mol%. More preferably. Moreover, it is preferable that the usage-amount of the said diol (b-2) is 80 mol% or more of all the polyols used when manufacturing the said linear aliphatic polyester polyol, and is 90 mol% or more. Is more preferable. If it is this range, the crystallinity of a linear aliphatic polyester polyol will become suitable, and the crystallinity of the obtained polyurethane resin (B-PU) can also be made suitable.

  Examples of the diisocyanate (b-6) include 1,4-tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate, 1,12-dodecamethylene diisocyanate, 2,4-diisocyanatotoluene, 2,2′-, 2,4′- or 4,4′-diisocyanatodiphenylmethane (MDI) or the like can be used.

When producing a polyurethane resin (B-PU), the aliphatic polyol (b-5) is reacted at a blending ratio of 60 to 95% by weight and the diisocyanate (b-6) at a blending ratio of 5 to 20% by weight. Is preferred. When the reaction is carried out at such a blending ratio, the crystallinity of the polyurethane resin becomes suitable, and the crystallization speed can be improved.
Moreover, when manufacturing a polyurethane resin (B-PU), well-known and publicly used polyols other than the said aliphatic polyol (b-5) and the said diisocyanate (b-6), polyisocyanate, polyamine, and amino alcohol are used. You can also

  Moreover, when manufacturing a polyurethane resin (B-PU), polyurethane is obtained by using a monoalcohol having 1 to 20 carbon atoms and a polyether monool blocked with a monoalcohol having 1 to 20 carbon atoms. The molecular weight and the outflow start temperature of the resin (B-PU) can be controlled.

In addition, in the equivalent ratio of isocyanate group / active hydrogen atom-containing group, the molecular weight is obtained by reacting under the condition of isocyanate group / active hydrogen atom-containing group = 1 (less than the active hydrogen atom-containing group is more than the isocyanate group). And the outflow start temperature can be controlled.
By using such a polyurethane resin (B-PU), the thermal meltability of the resin in the dispersed particles constituting the polyurethane resin aqueous dispersion of the present invention is enhanced, the initial adhesiveness immediately after adhesion is improved, After the combination, it is possible to improve the adhesive properties accompanying the crystallization of the polyurethane resin.

  Further, when the polyurethane resin (B-PU) is used as the hydrophobic resin (B), the use of the polyurethane resin in which the isocyanate group does not remain basically means that the aqueous polyurethane resin dispersion of the present invention has excellent Although it is preferable because performance can be exhibited more effectively, a polyurethane resin containing some isocyanate groups remaining at the time of production can also be used.

Next, the manufacturing method of the polyurethane resin aqueous dispersion of this invention is demonstrated.
The aqueous polyurethane resin dispersion of the present invention can be produced by combining various known methods.
For example, a polyurethane resin (A) having an anionic group is produced by reacting a polyisocyanate with a polyol having a carboxyl group and / or a sulfonic acid group, and the obtained polyurethane resin (A) and a previously melted hydrophobic resin A method in which the water-soluble resin (B) is mixed and uniformly melted, then neutralized, and water or an aqueous solution containing an emulsifier is added to the mixture for emulsification and dispersion.

A polyisocyanate and a polyol having a carboxyl group and / or a sulfonic acid group are reacted with a hydroxyl group of the polyol under a condition that the isocyanate group of the polyisocyanate is excessive to produce a prepolymer containing an isocyanate group. The obtained prepolymer and the previously melted hydrophobic resin (B) are mixed, then the mixture is neutralized, and water or an aqueous solution containing an emulsifier is added to the mixture for emulsification and dispersion. A method in which a polyamine is added to the liquid to cause chain elongation (high molecular weight) of the prepolymer (a polyurethane resin (A) is produced);

Using a polyamine having an anionic group, a polyisocyanate and a polyol are reacted with a hydroxyl group of the polyol under a condition in which the isocyanate group of the polyisocyanate is excessive to produce an isocyanate group-containing prepolymer. Polyurethane resin (A) is produced by chain extension, and then the obtained polyurethane resin (A) and the previously melted hydrophobic resin (B) are mixed, and then water or an aqueous solution containing an emulsifier is added to the mixture. In addition, a method of emulsifying and dispersing can be mentioned.

The method for producing the aqueous polyurethane resin dispersion of the present invention will be described with reference to more specific examples.

<Example 1 of Production Method of Polyurethane Resin Aqueous Dispersion>
In an organic solvent that does not contain an active hydrogen atom-containing group in the molecule, the organic polyisocyanate and the polyol are generally referred to as an isocyanate group (hereinafter abbreviated as NCO group) under the conditions of preferably 30 to 150 ° C., more preferably 50 to 120 ° C. ) And a hydroxyl group (hereinafter abbreviated as OH group), preferably within a range of preferably NCO group: OH group = (3-1): 1, more preferably (2-1): 1. Or it is set as the prepolymer by which a NCO group remains by a multistage method.
Under the present circumstances, the prepolymer which has an anionic group can be obtained by using the polyol containing a carboxyl group and / or a sulfonic acid group as a polyol raw material. The obtained prepolymer and the previously melted hydrophobic resin (B) are mixed and melted uniformly. In particular, when the prepolymer containing a hydrophilic group and the hydrophobic resin (B) are mixed, it is important to keep the temperature at 60 ° C. or lower so that the NCO group and the active hydrogen atom-containing group of the hydrophobic resin do not react.

  Next, after neutralizing the mixture, water or an aqueous solution containing an emulsifier is added dropwise or divided into the mixture for emulsification and dispersion. At this time, it is important to emulsify at 60 ° C. or lower in order to suppress side reactions with water.

Next, chain elongation (high molecular weight) is performed by adding an aqueous solution containing an amine compound to the obtained emulsion dispersion in which the NCO groups remain. At this time, the amine group (hereinafter abbreviated as NH group) is equivalent to the remaining NCO group of the prepolymer, and usually preferably NCO group: NH group = 1: (0.5 to 1.2), more preferably 1: By carrying out at (0.5-1.0), high molecular weight becomes possible and durability improves.
Further, by removing the obtained emulsified dispersion as necessary, an aqueous dispersion with less harmfulness can be obtained.

<Example-2 of production method of aqueous polyurethane resin dispersion>
One shot of the organic polyisocyanate and polyol in an equivalent ratio of NCO group and OH group is usually preferably NCO group: OH group = (3-1): 1, more preferably (2-1): 1. By the method or the multistage method, a prepolymer having no organic solvent and having NCO groups remaining is obtained. After the prepolymerization is completed, acetone is added to obtain a prepolymer solution. The solution is subjected to chain extension using a diaminosulfonate compound (a diamine containing a sulfonate group). Next, the obtained polyurethane resin solution and the previously melted hydrophobic resin (B) are mixed, and then water or an aqueous solution containing an emulsifier is dropped or divided into the mixture to carry out emulsification dispersion. Next, by removing the solvent of the obtained emulsified dispersion as necessary, an aqueous dispersion with less harmfulness can be obtained.

<Example-3 of production method of aqueous polyurethane resin dispersion>
In an organic solvent that does not contain an active hydrogen atom-containing group in the molecule, the organic polyisocyanate and the polyol are equivalent to NCO groups and OH groups under the conditions of preferably 30 to 150 ° C., more preferably 50 to 120 ° C. The ratio is usually NCO group: OH group = (1.1 to 0.9): 1, more preferably (1.05 to 1): 1, and it remains by the one-shot method or multistage method. It is made to react until NCO group is lost, and it is set as a polyurethane resin solution. Under the present circumstances, the polyurethane resin containing an anionic group can be obtained by using the polyol containing a carboxyl group and / or a sulfonic acid group as a polyol raw material. The obtained polyurethane resin (A) and the previously melted hydrophobic resin (B) are mixed and uniformly melted and then neutralized, and water or an aqueous solution containing an emulsifier is dropped or dividedly added to the mixture. To emulsify and disperse. Next, by removing the solvent of the obtained emulsified dispersion as necessary, an aqueous dispersion with less harmfulness can be obtained.

  The ratio of the polyurethane resin (A) to the hydrophobic resin (B) used in the present invention is, by weight ratio, polyurethane resin (A) / hydrophobic resin (B) = 99/1 to 50/50, preferably 95 / It is in the range of 5-50 / 50. If the ratio of the polyurethane resin (A) to the hydrophobic resin (B) is within such a range, stable particle formation is possible without impairing water dispersibility, and the cohesive strength of the resin is within a suitable range, so that processing can be performed at a low temperature. The initial adhesiveness when performing is improved.

  As an organic solvent used when producing the polyurethane resin aqueous dispersion of the present invention, considering the formation of fine particles during emulsification and removal of the residual solvent contained in the polyurethane resin aqueous dispersion after desolvation. It is preferable to use an organic solvent having a boiling point of 150 ° C. or lower.

Examples of the organic solvent having a boiling point of 150 ° C. or lower include benzene, toluene, ethyl acetate, acetone, methyl ethyl ketone, diethyl ether, tetrahydrofuran, methyl acetate, acetonitrile, chloroform, methylene chloride, carbon tetrachloride, 1,2-dichloroethane, 1, 1,2-trichloroethane, tetrachloroethylene and the like may be mentioned, and these may be used alone or in a mixed solvent. Among them, it is particularly preferable to use acetone or methyl ethyl ketone as a solvent having high solubility in the polyurethane resin. Further, for the purpose of enhancing the emulsifying dispersibility, an alcohol solvent such as methanol, ethanol, isopropyl alcohol or the like may be used at the time of emulsifying dispersion within a range that does not inhibit the increase in the molecular weight.
In addition, as a film forming aid, a solvent such as N-methyl-2-pyrrolidone, ethyl cellosolve, n-butyl cellosolve, propylene glycol methyl ether is used with respect to the total amount of polyurethane resin (A) and hydrophobic resin (B) used. It can be used at a content of 50% by weight or less.

  As described above, an emulsifier may be used when the polyurethane resin aqueous dispersion of the present invention is produced. Examples of such emulsifiers include polyoxyethylene polyoxypropylene glycol ether type, polyoxyethylene nonyl phenyl ether type, polyoxyethylene octyl phenyl ether type, polyoxyethylene laurate type, polyoxyethylene alkyl ether type, sorbitan derivative type, Nonionic emulsifiers such as polyoxyethylene polycyclic phenyl ether type, anionic emulsifiers such as alkylbenzene sulfonate type and dialkyl succinate sulfonate type, cationic emulsifiers, and zwitterionic emulsifiers.

  Among these emulsifiers, nonionic emulsifiers and / or anionic emulsifiers are preferable, and the content of the emulsifier is preferably 5% by weight or less, more preferably 0.01 to 5% by weight, based on the polyurethane resin (A). . Within such a range, stable particle formation is possible without impairing water resistance. When these emulsifiers are used, it is preferable to add them to the polyurethane solution before the emulsifying and dispersing step or the prepolymer in which the isocyanate groups remain, and then emulsify and disperse them, but they may be added after the end of the emulsifying and dispersing step.

  In the polyurethane resin aqueous dispersion of the present invention, in order to achieve particularly excellent performance such as coating workability such as permeability and spreadability, the polyurethane resin water dispersion of the present invention is adjusted by adjusting the content of the emulsifier. The surface tension of the body is preferably 40 mN / m or less.

  When an emulsifier is used for the purpose of controlling the surface tension, the content of the emulsifier is preferably 0.1 to 5.0 weight based on the total amount of the polyurethane resin (A) and the hydrophobic resin (B) used. %, More preferably 0.1 to 2.0% by weight. If it is this range, it will become possible to reduce the surface tension of the polyurethane resin aqueous dispersion of this invention, without impairing water resistance, and the wettability (leveling property) and permeability with respect to a base material will improve.

  A urethanization catalyst can be used if necessary in producing the aqueous polyurethane resin dispersion of the present invention. For example, various nitrogen-containing compounds such as triethylamine, triethylenediamine, or N-methylmorpholine, potassium acetate, stearin Examples thereof include various metal salts such as zinc acid or tin octylate, and various organometallic compounds such as dibutyltin dilaurate.

  The aqueous adhesive and the aqueous primer coating agent of the present invention comprise the above-described aqueous polyurethane resin dispersion of the present invention, and the aqueous polyurethane resin dispersion of the present invention itself is an aqueous adhesive or It can be used as an aqueous primer coating agent. In addition, a composition comprising an aqueous polyurethane resin dispersion of the same design can be used as an aqueous adhesive or an aqueous primer coating agent.

  The aqueous adhesive and the aqueous primer coating agent of the present invention include an aqueous dispersion of a polyurethane resin other than the aqueous polyurethane resin dispersion of the present invention, an aqueous dispersion other than a polyurethane resin represented by an SBR latex resin and an acrylic emulsion, [ Polyurethane resin aqueous dispersion solid content / total solid content x 100], preferably in the range of 1 to 100% by weight, more preferably in the range of 50 to 100% by weight. .

  Furthermore, auxiliary materials and additives used for ordinary aqueous adhesives or aqueous primer coating agents, such as plasticizers and tackifiers (for example, rosin), as long as they do not inhibit the cohesiveness of the aqueous polyurethane resin dispersion of the present invention. Resin, rosin ester resin, terpene resin, terpene phenol resin, petroleum resin, coumarone resin, etc.), fillers, pigments, thickeners, antifoaming agents, antioxidants, UV absorbers, flame retardants, preservatives, etc. It is also possible to do.

  The aqueous polyurethane resin dispersion of the present invention can be used alone, but for the purpose of further improving the durability, it is a bifunctional or higher functional group such as an amino resin, an epoxy compound, an aziridine compound, a carbodiimide compound, an oxazoline compound, or a polyisocyanate. A thing can also be used as a crosslinking agent. Among these, polyisocyanate is preferable, and the polyisocyanate can be preferably used at 50% by weight or less based on the solid content of the polyurethane resin.

  Illustrative examples of the above polyisocyanates include 1,4-tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate, 4,4′-diisocyanatodiphenylmethane (MDI), xylylene diisocyanate, isophorone diisocyanate and the like. Isocyanate group consisting of polyisocyanate consisting of a monomer, or low molecular active hydrogen compounds such as polyisocyanate and ethylene glycol, 1,3-butylene glycol, 1,4-butylene glycol, polyoxyethylene glycol, long-chain higher alcohol, etc. Examples include terminal compounds.

The water-based adhesive of the present invention is excellent in adhesive strength, low-temperature processing conditions (drying temperature), adhesiveness to a wide range of substrates, heat resistance, polyvinyl chloride (PVC) and other plastics, leather, rubber, foam It is widely used for textile products, metals, glass, etc. and is useful.
Further, the aqueous primer coating agent of the present invention is excellent in adhesive strength, heat resistance, permeability to a substrate, leveling property, etc., plastic such as polyvinyl chloride (PVC), leather, rubber, foam, textiles, It is useful for a wide range of metals and glass.

Hereinafter, the present invention will be described more specifically with reference to examples. In the following, “part” and “%” are all based on weight unless otherwise specified.
The evaluation method regarding the polyurethane resin aqueous dispersion of the present invention will be described below.

[Evaluation method of initial adhesiveness]
An aqueous adhesive comprising a polyurethane resin aqueous dispersion was applied to two substrates with a brush, dried (50 ° C. × 6 minutes), the two substrates were bonded together, and further pressed with a rubber roller. . After 1 minute, the adhesive surface was peeled by hand, the degree of cohesive failure of the adhesive was visually observed, and the quality of the initial adhesiveness was evaluated from the biting state of the adhesives according to the following criteria.

Type of adhesive substrate:
1) Polyvinyl chloride (PVC) sheet 2) Vulcanized rubber (SBR) sheet

(Double-circle): The state where adhesives cohesively break while pulling the thread at the time of peeling, and there is no interface peeling between the base material and the adhesive.
○: A state in which the adhesives cohesively break while pulling the yarn during peeling, and a part of the interface peeling between the base material and the adhesive is observed.
(Triangle | delta): There is no stringing of adhesives at the time of peeling, and a base material and an adhesive peel at an interface.
X: The state which does not have a feeling of resistance and peels easily.

[Leveling evaluation method]
In the same manner as described above, an aqueous adhesive made of an aqueous polyurethane resin dispersion was applied to a substrate using a brush, and the quality of the uniform application of the adhesive liquid surface was visually evaluated according to the following criteria.

A: The liquid surface of the adhesive is smooth.
○: The liquid surface of the adhesive is almost smooth.
Δ: Unevenness in the height of the liquid surface of the adhesive.
X: The liquid level of the adhesive is not smooth, and there is a partial repellency.

[Evaluation method of brush coatability]
The spreadability of the adhesive when an aqueous adhesive comprising a polyurethane resin aqueous dispersion was applied to a substrate using a brush was evaluated by visual observation according to the following criteria.

A: Light and uniform application is possible.
○: Light and almost uniform application is possible.
Δ: Application is heavy and uniform application is difficult.
X: Application is heavy and uniform application is not possible.

[Measurement method of tack time]
An aqueous adhesive comprising a polyurethane resin aqueous dispersion is applied to both surfaces of two substrates, dried for a predetermined time, taken out from the dryer, 1 minute, 3 minutes, 5 minutes, 7.5 minutes, and 10 minutes. After each time, the two substrates were bonded and pressure-bonded with a rubber roller. A 1.5 kg load was suspended at room temperature, and a creep test (180 degrees) was performed for 10 seconds between the marked lines of the base material for 30 seconds. What peeled off the whole surface (10 cm) of bonding was made disqualified. The longest time during which the entire surface was not peeled was defined as the tack time (minute) of the sample.

[Evaluation method of initial adhesive strength]
After applying 100 g / m ^{2 of} polyurethane resin aqueous dispersion adhesive to two substrates of 2 mm (thickness) x 20 mm (width) x 300 mm (length) with a brush, circulating hot air at 50 ° C for 6 minutes Reactivate it in the dryer. The adhesive surfaces of the adhesive base material taken out from the dryer were pressed together with a rubber roller and bonded together, and the peel strength after 2 minutes from the bonding was measured with a digital force gauge.

Type of adhesive substrate:
1) PVC sheet 2) SBR sheet

[Method of evaluating peel strength over time]
About the bonded test piece produced in the same manner as the evaluation of the initial adhesive strength, the peel strength after 2 hours of bonding and after 1 day of bonding is 180 ° under the measurement condition of a tensile speed of 100 mm / min with a tensile tester. The peel strength was measured.

Type of adhesive substrate:
1) PVC sheet 2) SBR sheet

[Method of evaluating heat-resistant creep resistance]
A bonded specimen prepared in the same manner as in the evaluation of the initial adhesive strength was cured at room temperature for 3 days. A weight of 1 kg was hung on the test piece, placed in a hot air circulating dryer at 70 ° C. for 30 minutes, and a heat-resistant creep test in the direction of 180 degrees was performed. The distance (mm) at which the 100 mm marked line was peeled off or the time when the weight dropped was measured.

[Number average molecular weight (Mn)]
Tetrahydrofuran (THF) was used as an eluent, measured by gel permeation chromatography (GPC) (measurement model: Tosoh High Speed GPC HLC-8220), and obtained from a calibration curve prepared using standard polystyrene.

[Outflow start temperature (X)]
Using a dry film of the hydrophobic resin (B) as a sample, and using a flow tester (CFT-500D CAPILLARY RHEOMETER manufactured by Shimadzu Corporation) for 10 minutes at 40 ° C., die inner diameter 1 mm × 1 mm length, load 10 kg The temperature was raised at a rate of 3 ° C./minute, and after the piston was slightly raised due to the thermal expansion of the sample, the outflow start temperature (° C.) at which the piston clearly began to fall again was measured.
In addition, when the outflow start temperature (X) of the sample is 40 ° C. or lower, the sample flows out from the die even when the sample is held at 40 ° C., and the accurate outflow start temperature (X) cannot be obtained. However, in this case, the outflow start temperature (X) of the sample was evaluated as “40 ° C. or less”.

[Crystallizing temperature (Y)]
Using a resin dry film as a sample, a differential scanning calorimeter (DSC) (DSC Q100 manufactured by TA Instruments Co., Ltd.) was used for measurement under the following conditions. Asked.
・ Temperature raising process (0 ° C → 60 ° C: Temperature rising rate 3 ° C / min)
・ Temperature lowering process (60 ° C → -20 ° C: temperature decreasing rate 3 ° C / min)
* Holding time from temperature rising process to temperature falling process = within 1 minute

* When the crystallization temperature (Y) is lower than −20 ° C., since the crystallization speed is slow and the development of the adhesive strength is also delayed, it cannot be put to practical use. Measurements were made at ° C.

<< Production Example 1 >> Preparation of Aromatic Sulfonate Metal Base-Containing Polyester Polyol (1) While introducing nitrogen gas in a reaction vessel equipped with a thermometer, nitrogen gas introduction tube, and stirrer, dimethyl 5-sulfosodium isophthalate (DMS) 1480 parts, 1,6-hexanediol 1240 parts, and dibutyltin oxide 0.5 parts were charged, and the reaction temperature was 180 to 190 ° C. so that the tower top temperature was 60 to 70 ° C. The transesterification reaction was carried out until the acid value of 1 became 1 or less, and then the reaction was carried out at 210 ° C. for 2 hours. Next, after cooling to 100 ° C., 2280 parts of ε-caprolactone was charged and subjected to a ring-opening polymerization reaction at 180 ° C. for 3 hours, whereby a polyester polyol having a hydroxyl value of 120 and an acid value of 0.3 as shown in Table 1 ( 1) was obtained.

<< Production Example 2 >> Preparation of hydrophobic resin

  Polyester polyol obtained by reacting 1,4-butylene glycol and adipic acid (number average molecular weight 4,800, hydroxyl value = 23.5, acid value = 0.3) was designated as hydrophobic resin (P-1). . When the outflow start temperature (X) and the crystallization temperature (Y) of this resin were measured, the outflow start temperature (X) was 40 ° C. or less, and the crystallization temperature (Y) was 36 ° C.

  A polyester polyol (number average molecular weight 2,000, hydroxyl value = 56, acid value = 0.3) obtained by reacting neopentyl glycol and adipic acid was defined as a hydrophobic resin (P-2). When the outflow start temperature (X) of this resin was measured, the outflow start temperature (X) was 40 ° C. or less, and the crystallization temperature (Y) was measured. As a result, an exothermic peak appeared in the temperature lowering step 60 ° C. to −20 ° C. The crystallization temperature (Y) was not confirmed.

  Polypropylene glycol (number average molecular weight 400, acid value = 0.01) was used as the hydrophobic resin (P-3). When the outflow start temperature (X) of this resin was measured, the outflow start temperature (X) was 40 ° C. or less, and the crystallization temperature (Y) was measured. As a result, an exothermic peak appeared in the temperature lowering step 60 ° C. to −20 ° C. The crystallization temperature (Y) was not confirmed.

  Add 100 parts of polyester (hydroxyl value = 37.4) obtained by reacting 1,4-butylene glycol and adipic acid, 3 parts of neopentyl glycol and 55 parts of methyl ethyl ketone, and dissolve well by stirring. 12 parts of diisocyanate was added and reacted at 80 ° C. for 3 hours. Next, 28 parts of methyl ethyl ketone was added, and after cooling to 60 ° C., 10 parts of polyester (hydroxyl value = 190) obtained by reacting 1,4-butylene glycol and adipic acid was added, and the isocyanate value was 0.1%. The reaction was carried out at 80 ° C. until it became less than that, to obtain a urethane hydrophobic resin (U-1) having a nonvolatile content of 60% and a number average molecular weight of 15,000. When the outflow start temperature (X) and the crystallization temperature (Y) of this resin were measured, the outflow start temperature (X) was 40 ° C. or less, and the crystallization temperature (Y) was 30 ° C.

  100 parts of polypropylene glycol (hydroxyl value = 56.1), 3 parts of neopentyl glycol and 143 parts of methyl ethyl ketone were added and sufficiently stirred to dissolve. 112 parts of isophorone diisocyanate (abbreviated as IPDI) was added and the isocyanate value was 0 at 80 ° C. The reaction was carried out at 80 ° C. until it became less than 1% to obtain a urethane hydrophobic resin (U-2) having a nonvolatile content of 60% and a number average molecular weight of 8,500. When the outflow start temperature (X) of this resin was measured, the outflow start temperature (X) was 40 ° C. or less, and the crystallization temperature (Y) was measured. As a result, an exothermic peak appeared in the temperature lowering step 60 ° C. to −20 ° C. The crystallization temperature (Y) was not confirmed.

Example 1
50 parts of polyester polyol (1) obtained in Reference Example 1 and 90 parts of methyl ethyl ketone were sufficiently stirred and dissolved, and 55 parts of isophorone diisocyanate (abbreviated as IPDI) was added and reacted at 80 ° C. for 3 hours. Next, after adding 150 parts of methyl ethyl ketone (abbreviated as MEK) and cooling to 60 ° C., polyester obtained by reacting 1 part of neopentyl glycol, 1,4-butylene glycol and adipic acid (hydroxyl value = 56.1). 255 parts were added and reacted at 80 ° C. When the isocyanate value became 0.79% or less, the reaction product was cooled to 50 ° C. to obtain a hydrophilic urethane prepolymer. 90 parts of a previously melted hydrophobic resin (P-1) was added and mixed uniformly.

  Next, after adding 525 parts of water and emulsifying and dispersing, 43.8 parts of a 10% piperazine aqueous solution (90 equivalent% as amine groups with respect to the remaining isocyanate groups) was added and emulsified and dispersed. The obtained emulsion was desolvated to obtain an aqueous dispersion having a nonvolatile content of 50%. Isocyanate CR-60N (polyisocyanate compound; Dainippon Ink, which can be dispersed in water as a crosslinking agent after adding 1 part of urethane-based associative thickener to 100 parts of the resulting aqueous dispersion to increase the viscosity. The adhesive was adjusted by adding 5 parts of Chemical Industries, Ltd. Table 2-1 shows the blend composition.

Next, the prepared adhesive was applied to two PVC sheets and SBR sheets with a brush at 100 g / m ² , and then the adhesive surfaces were bonded to each other to evaluate each adhesive performance. The coating surface of the adhesive applied with a brush showed a uniform film thickness. Moreover, it was excellent also in the adhesive strength and heat resistance immediately after bonding and after 1 day, and the tack time was also long and excellent in line suitability.

Example 2
As shown in Table 2, the same operation as in Example 1 was performed except that the hydrophobic resin (U-1) was used instead of the hydrophobic resin (P-1) in Example 1, and the non-volatile content was 50%. An aqueous dispersion was obtained. After the adhesive was prepared in the same manner as in Example 1 using the obtained aqueous dispersion, the adhesive surfaces were bonded together and evaluated for each adhesive performance. As shown in Table 4, the PVC substrate Both rubber base materials were excellent in adhesive strength and heat resistance.

Example 3
As shown in Table 2, an aqueous dispersion was prepared by adding 0.7 part of a dialkylsulfosuccinic acid ester soda salt (active ingredient 70%) to 100 parts of the aqueous dispersion obtained in Example 2. After preparing an adhesive in the same manner as in Example 1 using this aqueous dispersion, the adhesive surfaces were bonded to each other, and each adhesive performance was evaluated. As shown in Table 4, the PVC base material and the rubber base Both materials were excellent in adhesive strength and heat resistance.

<< Comparative Example 1 >>
Polyester (hydroxyl value) obtained by reacting 100 parts of a copolymer (hydroxyl value = 30.2) of ethylene oxide-propylene oxide containing 90% ethylene oxide units, 1,4-butylene glycol and adipic acid = 56.1) 50 parts was stirred and dissolved in 111 parts of methyl ethyl ketone, 17 parts of isophorone diisocyanate (abbreviated as IPDI) was added and reacted at 80 ° C. for 5 hours. When the isocyanate value was 0.74% or less, It cooled to 50 degreeC and obtained the hydrophilic urethane prepolymer. 278 parts of a previously melted hydrophobic resin (U-1) was added and mixed uniformly.

  Subsequently, 500 parts of water was added and emulsified and dispersed, and then 16.9 parts of a 10% piperazine aqueous solution (90 equivalent% as an amine group with respect to the remaining isocyanate groups) was added and emulsified and dispersed. The obtained emulsion was desolvated to obtain an aqueous dispersion having a nonvolatile content of 50%. The obtained aqueous dispersion has a high viscosity, and 5 is used as an isocyanate CR-60N (polyisocyanate compound; manufactured by Dainippon Ink & Chemicals, Inc.) that can be dispersed in water as a crosslinking agent without using a thickener. The adhesive was adjusted by adding parts. As shown in Table 4, the adhesive strength and heat resistance were not sufficient for any of the substrates as shown in Table 4.

<< Comparative Example 2 >>
As shown in Table 2, the same operation as in Example 1 was performed except that the amount of the hydrophobic resin (U-1) used in Example 2 was changed to 1116 parts, but the water dispersion stability after emulsification was improved. As a result, it aggregated as a result, and applicability, adhesion, etc. could not be evaluated.

<< Comparative Example 3 >>
As shown in Table 3, the same operation as in Example 1 was performed except that the hydrophobic resin (P-1) of Example 1 was not used, and an aqueous dispersion having a nonvolatile content of 50% was obtained. After the prepared aqueous dispersion was prepared in the same manner as in Example 1, the adhesive surfaces were bonded together and evaluated for each adhesive performance. As shown in Table 5, the PVC base material was Although the adhesive strength and heat resistance were relatively good, the rubber base material in which the base material temperature hardly rises was not sufficient in both adhesive strength and heat resistance.

<< Comparative Example 4 >>
As shown in Table 2, the same operation as in Example 1 was performed except that the hydrophobic resin (P-2) was used instead of the hydrophobic resin (P-1) in Example 1, and the non-volatile content was 50%. An aqueous dispersion was obtained. After the prepared aqueous dispersion was prepared in the same manner as in Example 1, the adhesive surfaces were bonded together and evaluated for each adhesive performance. Although the coating suitability was good, the adhesive strength and heat-resistant creep resistance were not sufficient because the crystallization and cohesive force of the adhesive were hindered.

<< Comparative Example 5 >>
As shown in Table 3, the same operation as in Example 1 was performed except that the hydrophobic resin (P-3) was used instead of the hydrophobic resin (P-1) of Example 1, and the non-volatile content was 50%. An aqueous dispersion was obtained. After the prepared aqueous dispersion was prepared in the same manner as in Example 1, the adhesive surfaces were bonded together and evaluated for each adhesive performance. Although the coating suitability was good, the adhesive strength and heat-resistant creep resistance were not sufficient because the crystallization and cohesive force of the adhesive were hindered.

<< Comparative Example 6 >>
As shown in Table 3, the same operation as in Example 1 was performed except that the hydrophobic resin (U-2) was used instead of the hydrophobic resin (P-1) in Example 1, and the non-volatile content was 50%. An aqueous dispersion was obtained. After the prepared aqueous dispersion was prepared in the same manner as in Example 1, the adhesive surfaces were bonded together and evaluated for each adhesive performance. Although the coating suitability was good, the adhesive strength and heat-resistant creep resistance were not sufficient because the crystallization and cohesive force of the adhesive were hindered.

* Unconfirmed crystallization temperature (Y): When the crystallization temperature (Y) was measured, no exothermic peak appeared in the temperature lowering step 60 ° C. to −20 ° C., and the crystallization temperature (Y) was not confirmed. Is “unconfirmed” in the above table.

The water-based adhesive of the present invention is excellent in adhesive strength, low-temperature processing conditions (drying temperature), adhesiveness to a wide range of substrates, heat resistance, polyvinyl chloride (PVC) and other plastics, leather, rubber, foam It is widely used for textile products, metals, glass, etc. and is useful. Further, the aqueous primer coating agent of the present invention is excellent in adhesive strength, heat resistance, permeability to a substrate, leveling property, etc., plastic such as polyvinyl chloride (PVC), leather, rubber, foam, textiles, It is useful for a wide range of metals and glass. Therefore, the present invention is extremely useful industrially.

Claims (4)

A self-emulsifying polyurethane resin (A) having an anionic group, and an outflow start temperature (X) of 60 ° C. or less and a crystallization temperature (Y) of 0 to 50 ° C., and having hydrophobicity A dispersion particle containing a substantially linear polyurethane resin (B-PU), and an aqueous dispersion containing an aqueous medium,
The ratio of the polyurethane resin (A) to the polyurethane resin (B-PU) is in the range of (A) / (B-PU) = 99/1 to 50/50 by weight ratio, and the polyurethane resin (B- PU) is succinic acid, succinic anhydride, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, or ε-caprolactone, ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1 , 5-pentanediol, 1,6-hexanediol, diethylene glycol, triethylene glycol, or tetraethylene glycol is reacted as an essential component with a linear aliphatic polyester polyol of 60 to 95% by weight and diisocyanate (b -6) It is obtained by reacting 5 to 20% by weight as an essential component. Urethane resin aqueous dispersion. Content of ethylene oxide [(CH ₂ CH ₂ O) _n ; n = 5 or more] constituent unit having an ionic group content of the polyurethane resin (B-PU) of 50 mmol / kg or less and a repeating unit of 5 or more. The aqueous polyurethane resin dispersion according to claim 1, wherein is 5% by weight or less. The aqueous polyurethane resin dispersion according to claim 1, wherein the surface tension is 40 mN / m or less. An aqueous adhesive for shoes comprising the aqueous polyurethane resin dispersion according to any one of claims 1 to 3 .