JPH04293986A - Two-pack water-base urethane adhesive and emulsion as its principal component - Google Patents

Abstract

PURPOSE:To obtain an adhesive having high adhesive power both initially and in an ordinary state without any pretreatment by incorporating a polyisocyanate compound into an emulsion containing a specified polyurethane compound and tackifier. CONSTITUTION:A polyester or polybutadiene glycol containing 8C or higher alkylene groups and a hydrophilic substance having at least one hydrophilic group and at least two functional groups reactive with isocyanate group are combined with a polyisocyanate compound to give a polyurethane reaction product, which is then made to react with a polyol to produce a polyurethane compound having terminal hydroxyl groups. The title two-pack adhesive consists of a principal component which comprises an emulsion obtained by mixing a first constitutent prepared by emulsifying the polyurethane compound in water and a second constituent prepared by emulsifying a tackifier having a softening point of 80 deg.C or higher in water, and a curing agent which comprises a polyisocyanate compound.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to a two-component adhesive of the type in which two components (base agent and curing agent) are mixed immediately before use. , relates to a water-based urethane two-component adhesive that exhibits high initial adhesive strength and normal adhesive strength when bonding to plastic members and wooden members.

0002

[Prior art and problems to be solved by the invention] Conventionally,
For example, when bonding a skin material such as a polyolefin foam member to a base material such as a plastic or wood member using a water-based adhesive, a polyester polyurethane rubber solvent-based adhesive is generally used, and this is applied to the base material side. After drying, a method such as pasting and pressing a preheated skin material is used.

However, when using the above-mentioned solvent-based adhesives, water-based adhesives are increasingly being used from the viewpoints of occupational safety and health, fire hazards, environmental pollution, resource conservation, etc. in the bonding work environment where the adhesive is applied and dried. The development of adhesives became desirable.

[0004] For this reason, recently, polyesters that are solid at room temperature are reacted with polyisocyanate compounds.
A two-component adhesive based on a polyester polyurethane emulsion containing a surfactant in its molecular structure has been developed and put into practical use. With this adhesive, problems of occupational safety and health, fire hazards, environmental pollution and resource saving are eliminated. However, since this type of adhesive has low adhesion to non-polar polyolefin, interfacial peeling is likely to occur between it and the substrate surface must be pretreated with a primer to achieve strong adhesion. There was a problem that the work became complicated.

The present invention has been made in view of the above circumstances, and its purpose is to eliminate the need for any pretreatment of polyolefin foam members, and to improve initial adhesive strength and normal adhesive strength. The purpose of the present invention is to provide an aqueous urethane two-component adhesive having both high properties and a curable emulsion as its main ingredient.

[0006]

[Means for Solving the Problems] A water-based urethane two-component adhesive according to the present invention for achieving the above object comprises a polyester or polybutadiene glycol (A) containing an alkylene group having 8 or more carbon atoms, and at least one hydrophilic group and at least two capable of reacting with an isocyanate group.
A hydroxyl group at the end of the molecule obtained by reacting a polyurethane-based reaction product obtained by bonding a hydrophilicity-imparting substance (B) with a polyisocyanate compound (C) with a polyol (D). An emulsion as a main ingredient obtained by mixing a first component obtained by emulsifying a polyurethane compound having and a polyisocyanate compound as a curing agent.

As the polyester (A) in the present invention, any polyester containing an alkylene group having 8 or more carbon atoms and having low polarity can be used without particular restriction. Such a polyester can be easily synthesized, for example, by a reaction using at least one of a diol having 8 or more carbon atoms and an aliphatic dicarboxylic acid. In this case, the diols include 1,8-octanediol, 1
, 9-nonionic diol, 1,10-decanediol,
Examples include 1,12-dodecanediol and 1,16-hexadecanediol, and examples of the aliphatic dicarboxylic acids include azelaic acid, sebacic acid, decanedioic acid, and dodecanedioic acid. The number of carbon atoms in the alkylene group can be within a range that does not cause poor compatibility with the other components and allows synthesis of polyester. In addition, as diols, ethylene glycol, propylene glycol, butylene glycol, hexanediol, etc. are used in combination, and as polybasic acids, phthalic acid, terephthalic acid, isophthalic acid, maleic acid, succinic acid, adipic acid, azelaic acid, sebacic acid. You can also use them together. In short, any one of the diols and the aliphatic dicarboxylic acid may contain a component having 8 or more carbon atoms. Further, examples of the polybutadiene glycol (A) in the present invention include polybutadiene having a hydroxyl group at the end of the molecule and hydrogenated products thereof. "Polybd-45HT" (trade name) manufactured by Idemitsu Petrochemical Co., Ltd. and "GI-2000" (trade name) manufactured by Nippon Soda Co., Ltd. are commercially available.

[0008] The hydrophilicity-imparting substance (B) in the present invention is
-COOH, -COONa, -C having at least two functional groups capable of reacting with isocyanate groups at the terminal or side chain and for emulsifying the polyurethane compound to be produced.
OONH4, -SO3H, -SO3Na, -SO
It has at least one hydrophilic group such as 3 NH4 in its molecule. Specific examples of such hydrophilicity-imparting substances include 2,2-dimethylolpropionic acid (DMPA), sulfonic acids shown in the following chemical formulas 1 and 2, and chemical compounds 3 and 4.
Examples include anionic water-solubility-imparting substances such as carboxylic acid-based substances shown in Chemical Formulas 5 and 6, and cationic water-solubility-imparting substances shown in Chemical Formulas 7 and 8 below.

[0009]

[Chemical formula 1]

0010

[Chemical 2]

[0011]

[Chemical formula 3]

0012

[C4]

[0013]

[C5]

[0014]

[C6]

[0015]

[C7]

[0016]

[Chemical formula 8]

The polyisocyanate compound (C) in the present invention is a crosslinking agent for bonding the saturated polyester polyol (A) and the hydrophilicity imparting substance (B) to obtain a polyurethane-based reaction product having isocyanate groups at both ends. It is. Such polyisocyanate compounds include:
Aliphatic or aromatic diisocyanates such as hexamethylene diisocyanate (HDI), diphenylmethane-4,4'-diisocyanate (MDI), tolylene diisocyanate (TDI), isophorone diisocyanate (IPDI), m-xylylene diisocyanate monomer (XDI); In addition to these hydrogenated compounds, HDI derivatives such as HDI trimethylolpropane (TMP) adduct trimer and isocyanurate trimer, MDI derivatives such as crude MDI, TDI TMP adduct trimer and isocyanurate trimer, etc. TDI derivatives such as body, TMP of IPDI
IPDI such as adduct trimer and isocyanurate trimer
Derivatives, XDI derivatives such as XDI TMP adduct trimer and isocyanurate trimer, tris (p-isocyanate phenyl) thiophosphate (manufactured by Bayer AG, trade name "Desmodur RF"), triphenylmethane triisocyanate (manufactured by Bayer AG, trade name "Desmodule R").

[0018] The polyol (D) in the present invention converts the isocyanate group at the end of the polyurethane reaction product into a hydroxyl group so that it can be crosslinked and cured by a curing agent (polyisocyanate compound) via a urethane bond. belongs to. Preferred specific examples of such polyols include ethylene glycol, propylene glycol,
Examples include low molecular weight compounds such as hexanediol, ethanolamine, butanediol.

The tackifier (E) in the present invention includes rosin resin, rosin ester resin, hydrogenated rosin ester resin, terpene resin, terpene phenol resin, hydrogenated terpene phenol resin, petroleum resin, and Examples include modified products thereof, particularly those having a softening point of 80°C or higher. The reason why the lower limit of the softening point is limited in this manner is that if the softening point is less than 80°C, it is difficult to obtain an adhesive with a large cohesive force. An example of a commercially available tackifier with such a high softening point is "Tamanol 803" (product code) manufactured by Arakawa Chemical Industry Co., Ltd., and a commercially available emulsion thereof is "E-100" manufactured by the same company. (product code) is exemplified.

[0020] Examples of the polyisocyanate compound as a curing agent in the present invention include the above-mentioned isocyanate compounds and derivatives thereof.

[0021] In addition to the above components, an emulsion stabilizer or the like may be added to the main ingredient if necessary.

As described above, the aqueous urethane two-component adhesive emulsion according to the present invention contains a first component consisting of a low polarity polyester or polybutadiene glycol (A) because it contains an alkylene group with a high carbon number. and a second component consisting of a tackifier component having a high softening point and a large cohesive force. Therefore, the adhesive according to the present invention having this as a main ingredient is particularly suitable for use when at least one of the adherends is a polyolefin foam member.

The emulsion as the main ingredient of the two-component adhesive according to the present invention is produced, for example, by a method comprising the following steps (1) to (2). [Step (2)] Polyester or polybutadiene glycol (A) is dissolved in an organic solvent such as acetone, methyl ethyl ketone (MEK), toluene, xylene, etc. in a reactor equipped with a heating means and a reflux device. [Step (2)] The water-solubility imparting substance (B) is added to the organic solution obtained in Step (2), and the temperature is raised and maintained at 40 to 100°C. [Step (2)] The polyisocyanate compound (C) is added to the liquid obtained in Step (2), and a bonding reaction is carried out with stirring for 2 to 12 hours to obtain a polyurethane-based reaction product. Catalysts such as amines and organic tin compounds may be added as necessary. [Step (2)] Polyol (D) is added to the solution of the polyurethane-based reaction product obtained in step (2) and reacted with stirring for 2 to 12 hours to convert the terminal isocyanate groups of the polyurethane-based reaction product into hydroxyl groups. [Step ■] The polyurethane compound having hydroxyl groups at both ends obtained in Step ■ is added to an alkaline aqueous solution containing triethylamine, etc., and emulsified using a homomixer. [Step (2)] The inside of the reactor is heated and depressurized to distill off the organic solvent from the emulsion obtained in Step (2). [Step ■] The first component obtained in the above step ■ and the second component obtained by emulsifying a tackifier (E) with a softening point of 80°C or higher in water are stirred and mixed to form an emulsion as a main ingredient. obtain.

[0024] The above method for producing the main ingredient of the present invention is merely an example, and it is of course not intended to exclude products produced by methods other than the above-mentioned production method.

[0025] When the base material obtained as described above is stirred and mixed with a curing agent to form an adhesive, and this is applied to an adherend and cured at room temperature or by heating, strong adhesion can be achieved. be done.

[0026]

[Examples] The present invention will be explained in more detail based on Examples below, but the present invention is not limited to the following Examples in any way, and may be practiced with appropriate modifications within the scope of the gist thereof. is possible.

(1) Synthesis of polyurethane ■ Synthesis of aqueous polyurethane A Polyester containing an alkylene group having 10 carbon atoms (1
, 10-decanediol and adipic acid esterification reaction product) in a reactor equipped with a heating means and a reflux device,
After dissolving in MEK, 2,2'-dimethylolpropionic acid was further added and the temperature was raised to 80°C and maintained. Next, HDI was added and reacted for 10 hours, and then ethylene glycol was further added and reacted for 10 hours. This reaction solution was poured into an aqueous solution of triethylamine and emulsified by stirring and mixing in a homomixer (13,000 rpm) for 30 minutes. After emulsification, MEK was removed under reduced pressure to obtain aqueous polyurethane A (emulsion). ■The above (1) except that hydrogenated polybutadiene (manufactured by Nippon Soda Co., Ltd., trade name "GI-2000") was used instead of the synthetic polyester in the emulsion of water-based polyurethane B.
) Water-based polyurethane B (emulsion) was obtained in the same manner as in (). ■Synthesis of non-aqueous polyurethane C Polyester containing an alkylene group having 10 carbon atoms (1
, 10-decanediol and adipic acid esterification reaction product) in a reactor equipped with a heating means and a reflux device,
After dissolving in MEK, the temperature was raised to 80°C and maintained. Next, HDI was added and reacted for 10 hours, ethylene glycol was further added and reacted for 10 hours, and then MEK
was removed under reduced pressure to obtain non-aqueous polyurethane C. (2) Synthesis of non-aqueous polyurethane D Non-aqueous polyurethane D was obtained in the same manner as in (1) (2) above, except that hydrogenated polybutadiene was used in place of the polyester. Table 1 shows the amount (in grams) of each raw material used in (1) (1) to (2) above as an adhesive.

[0028]

[Table 1]

(2) Examples 1, 2 and Comparative Examples 1 to 5 (Example 1) Water-based polyurethane A100 obtained in (1) (2) above
gram and 20 grams of tackifier A (manufactured by Arakawa Chemical Industry Co., Ltd., trade name "E-100") were mixed with stirring to prepare a main agent. Next, 12 grams of a curing agent (crude MDI) was added to 120 grams of this base resin and mixed with stirring to prepare a two-component adhesive. (Example 2) In place of water-based polyurethane A, (1)■
A two-component adhesive was prepared in the same manner as in Example 1, except that the aqueous polyurethane B obtained in Example 1 was used. (Comparative Example 1) Aqueous polyurethane A1 obtained in (1) ■ above
00 grams and 10 grams of a hardening agent (crude MDI) were added and mixed with stirring to prepare a two-component adhesive. (Comparative Example 2) Water-based polyurethane B1 obtained in (1) ■ above
00 grams and 10 grams of a hardening agent (crude MDI) were added and mixed with stirring to prepare a two-component adhesive. (Comparative Example 3) Tackifier A (“E-100”) 100
A two-component adhesive was prepared by adding 10 grams of a curing agent (crude MDI) to the mixture and stirring and mixing. (Comparative Example 4) Non-aqueous polyurethane C obtained in (1) ■ above
A base agent was prepared by stirring and mixing 100 grams of tackifier B (non-emulsified substance, manufactured by Arakawa Chemical Industries, Ltd., trade name: "Tamanol 803"). Next, this main ingredient 11
A two-component adhesive was prepared by adding 5 grams of a solvent-based curing agent (crude MDI) to 0 grams and stirring and mixing. (Comparative Example 5) Non-aqueous polyurethane D obtained in (1) ■ above
A main ingredient was prepared by stirring and mixing 100 grams of the tackifier B and 10 grams of the tackifier B. Next, 5 grams of a curing agent (crude MDI) was added to 110 grams of this base agent and mixed with stirring to prepare a two-component adhesive. Table 2 shows the above Example 1.
, 2 and Comparative Examples 1 to 5 (unit: grams) are shown below.

[0030]

[Table 2]

(3) Adhesive Strength Evaluation Test The initial adhesive strength and normal adhesive strength of each adhesive were measured by the following test method. That is, after spraying each adhesive onto a rigid base material (wood fiber board manufactured by Mitsui Mokuzai Co., Ltd., size 100 x 100 mm) at an application amount of 100 g/m2,
It was dried at C for 5 minutes. On the coating side of this rigid base material, 14
Skin material (Toray PEF) heated at 0°C for 4 minutes
, trade name "PPX", dimensions 100 x 100 mm) were bonded together and pressed together for 10 seconds with a pressure of 0.5 kg/cm2 to obtain Samples 1 and 2 and Comparative Samples 1 to 5. Next, each sample was cut to a width of 25 mm to obtain four test pieces, each of which was peeled off by 10 mm in the width direction, and then attached to a tensile tester and tested at a speed of 200 mm/min for 18 mm.
The peel strength (Kg/25 mm) was determined by peeling at 0°, and the average of the four test pieces was calculated to determine the adhesive strength. The results are shown in Table 3.

In Table 3, the initial adhesive strength is 1 at room temperature after pressure bonding.
The results are measured after being left for 0 minutes, and the normal adhesive strength is
The results are shown after being left at room temperature for one day after crimping. In addition, in the same table, MB indicates that the skin material has been destroyed (Ma
CF indicates that the adhesive layer has broken (Cohesive Failure),
Further, AF indicates failure at the interface between the skin material and the adhesive layer (Adhesive Failure).

[0033]

[Table 3]

From Table 3, it can be seen that in the case of the adhesives according to the present invention (Samples 1 and 2), both the initial adhesive strength and the normal adhesive strength are large because the skin material is destroyed. On the other hand, adhesives containing no tackifier emulsion (comparative samples 1 and 2) had high normal adhesive strength, but cohesive failure occurred in the initial adhesive strength test, and both aqueous and non-aqueous The adhesive that did not use any polyurethane (Comparative Sample 3) caused interfacial peeling in both the initial adhesion and normal adhesion tests, and the adhesive that contained non-aqueous polyurethane C or D (Comparative Sample 4) and 5), these non-aqueous polyurethanes did not mix with tackifier B, and could not be used for adhesive strength measurement.

[0035]

Effects of the Invention As explained above in detail, the water-based urethane two-component adhesive according to the present invention does not require any pre-treatment on adherends such as polyolefin foam members,
Moreover, the present invention exhibits excellent and unique effects, such as having a large adhesive force in both initial adhesion and normal adhesion.

Claims (3)

[Claims] Claim 1: A polyester or polybutadiene glycol (A) containing an alkylene group having 8 or more carbon atoms, and a hydrophilic polyester having at least one hydrophilic group and at least two functional groups capable of reacting with an isocyanate group. A polyurethane-based reaction product obtained by bonding the imparting substance (B) with a polyisocyanate compound (C) and a polyol (
A first component obtained by emulsifying in water a polyurethane compound having a hydroxyl group at the molecular end obtained by reacting with D), and a tackifier (E) having a softening point of 80°C or higher in water. A water-based urethane two-component adhesive comprising an emulsion as a main ingredient mixed with a second component and a polyisocyanate compound as a curing agent. 2. The water-based urethane two-component adhesive according to claim 1, wherein at least one of the adherends is a polyolefin foam member. 3. A polyester or polybutadiene glycol (A) containing an alkylene group having 8 or more carbon atoms, and a hydrophilic compound having at least one hydrophilic group and at least two functional groups capable of reacting with an isocyanate group. A polyurethane-based reaction product obtained by bonding a sex imparting substance (B) with a polyisocyanate compound (C) is reacted with a polyol (D), and a polyurethane compound having a hydroxyl group at the end of the molecule obtained is emulsified in water. An emulsion for an aqueous urethane two-component adhesive is prepared by mixing a first component obtained by emulsifying a tackifier (E) with a softening point of 80° C. or higher in water.