JPH0240105B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to polyurethane adhesives with improved adhesion to metals. Conventionally, polyurethane adhesives have poor adhesion to metals, and it has been difficult to stably adhere to metals without surface treatment. With conventional techniques, in order to firmly bond metals to each other or metals to plastics, etc., the surface of the metal is coated with acid or alkali, or with a primer (two-component, room-temperature curing epoxy adhesive) dissolved in the respective solvent. (referred to as a one-liquid primer), or a primer prepared by dissolving a resol resin or a phenolic resin in a solvent (referred to as a one-component primer). If these methods are used, the adhesion of polyurethane adhesives to metals can be greatly improved, but on the other hand, they have the following drawbacks. For example, acid or alkali treatment involves many treatment steps, requires strict control, and takes a long time. In addition, the two-component primer takes a long time to dry, and it takes about a day and a night to dry the primer at room temperature. Furthermore, a one-component primer requires high temperature heating of about 150°C to dry the primer. As a result, these drawbacks become an obstacle to the practical application of polyurethane adhesives, and their applications are also limited. As a result of research to improve these drawbacks, the present inventors discovered that the use of a certain type of phosphorus compound in a polyurethane adhesive significantly improves the adhesion to metals, leading to the present invention. That is, the present invention provides a curable polyurethane comprising (A) at least one polyisocyanate, (B) at least one active hydrogen compound, and (C) a compound represented by the following general formula (1). Provide adhesive. General formula (1): (However, in the formula, R is H or CH ₃ group, R ₁ is a group containing at least one SH group in the molecule,
R ₂ is H or R ₁ , X is a group containing an acidic phosphoric acid group, and n is an integer of 2 to 20. ) The embodiments of the adhesive of the present invention are shown in more detail as follows: (1)
"Compound represented by general formula (1)" (hereinafter "P compound")
) is a type of adhesive in which the polyisocyanate and the active hydrogen compound are stored separately, that is, the three components are stored separately, and the three components are brought into contact and mixed before use. An adhesive consisting of two components: a dissolved liquid and a liquid containing polyisocyanate, and (3) a primer solution containing a P compound dissolved in a volatile solvent, a liquid containing polyisocyanate, and a liquid containing an active hydrogen compound.
There are adhesives and the like made up of these ingredients. The components of the adhesive of the present invention will be explained below. Examples of polyisocyanates include toluene diisocyanate, diphenylmethane diisocyanate, triphenylmethane triisocyanate,
Examples include hexamethylene diisocyanate and derivatives thereof. Examples of active hydrogen compounds include (a) polyol;
For example, ethylene glycol, propylene glycol, glycerin, castor oil, and their derivatives such as polyether polyols and polyester polyols, (b) polyamines, such as aromatic polyamines such as ethylene diamine derivatives and methylene dianiline, and (c) polythiols. , for example 1,4
-butanediol, dimercaptoacetate, trimethylolpropane tris (mercaptoacetate), pentaerythritol tetrakis (mercaptoacetate), etc. Examples of P compounds include, for example, a compound obtained by polymerizing a reaction product of phosphoric acid and 2-hydroxyethyl methacrylate (hereinafter referred to as PM) in the presence of a thiol, or a compound obtained by polymerizing PM with trimethylolpropane trismercaptopropane. Pionate (below)
Examples include compounds obtained by polymerization in the presence of (referred to as TP). The degree of polymerization of the compound thus obtained is 20 or less. Examples of thiols used in the reaction with PM include 1,4-butanediol dimercaptoacetate (hereinafter referred to as BA), trimethylolpropane tris (mercaptoacetate), dipentaerythritol hexa (mercaptoacetate), 1,4- Examples include but are limited to butanediol dimercaptopropionate, trimethylolpropane tris (mercaptopropionate), pentaerythritol tetrakis (mercaptopropionate), dipentaerythritol hexa (mercaptopropionate), etc. isn't it. As examples of volatile solvents, acetone and ethyl acetate are preferred, but any solvent may be used as long as the P compound can be dissolved therein. For example, methanol, ethanol, water, etc., and mixtures thereof are used. The above P in the curable polyurethane adhesive of the present invention
The preferred content of the compound is 0.1 to 20% by weight, particularly preferably 0.5 to 10% by weight. Further, a catalyst, a plasticizer, a filler, a resin, etc. can be added to the polyurethane adhesive of the present invention, if necessary. Next, a preferred method of bonding metals using the polyurethane adhesive of the present invention will be introduced. That is, in this bonding method, when bonding metals using a curable polyurethane adhesive consisting of at least one type of polyisocyanate and at least one type of active hydrogen compound, the metal surface is bonded in advance.
It is characterized in that it is treated with a primer solution in which the compound represented by the above general formula (1) (P compound) is dissolved in a volatile solvent. The polyurethane adhesive of the present invention can be used to bond metals or metals to other adherends, such as cloth, wood, etc.
Adhesion of plastics, etc. can be carried out easily, and strong adhesion force can be obtained. In particular, a primer solution in which a P compound is dissolved can be dried within a short period of time, for example within 5 minutes, and the adhesion to metals is significantly improved. Reference Example P Preparation of Compound (A) Phosmer M ⁽¹⁾ 0.1 mol, BA ⁽²⁾ 0.1 mol, BPO ⁽³⁾
Place 0.001 mol in a four-necked 200 ml separable flask, stir while blowing nitrogen gas, and irradiate it with light from 5 cm from the flask at 25°C for 1 hour (Toshiba fluorescent lamp T-2300, F-100). )
and reacted. A portion of this reaction product was collected and analyzed using a high-speed liquid chromatograph (Waters, USA).
244 type), and the aliquots are subjected to NMR and IR analysis.
As a result of analysis, a reaction product of a phosmer polymer and BA (hereinafter referred to as compound A) with a degree of polymerization of 20 or less was obtained. (B) Hosmer M0.1 mol, TA ⁽⁴⁾ 0.1 mol,
Take 0.001 mole of BPO and perform the same operation as in (A) above to obtain a phosmer polymer with a degree of polymerization of 20 or less.
A reactant of TA (hereinafter referred to as compound B) was obtained. (C) Hosmer M0.1 mol, PA ⁽⁵⁾ 0.1 mol,
Take 0.001 mole of BPO and perform the same operation as in (A) above to obtain a phosmer polymer with a degree of polymerization of 20 or less.
A reactant of PA (hereinafter referred to as compound C) was obtained. (D) Phosmer M0.1 mol, TP ⁽⁶⁾ 0.1 mol,
Take 0.001 mole of BPO and perform the same operation as in (A) above to obtain a phosmer polymer with a degree of polymerization of 20 or less.
A reactant of TP (hereinafter referred to as compound D) was obtained. (E) Phosmer M0.1mol, BA0.2mol, BPO0.001
The moles were taken and the same operation as in (A) above was performed to obtain a reaction product of a phosmer polymer with a degree of polymerization of 10 or less and BA (hereinafter referred to as compound E). [Note] (1) Compound with the following structure (Unichemical Company product name) (2) Compounds with the following structure (3) Compounds with the following structure (4) Compounds with the following structure (5) Compounds with the following structure (6) Compounds with the following structure Example 1 A polyurethane adhesive was prepared by stirring in a beaker at room temperature for 5 minutes at the blending ratios shown in Experiment Nos. 1 to 6 in Table 1 below (hereinafter referred to as preparation liquid).
A portion of each prepared solution was applied to two 0.3 mm thick iron pieces (JIS G 314SPCC-SB) and adhered. After adhesion and curing for one week at room temperature, the T peel strength was measured at a temperature of 25°C, and the results are shown in Table 1.

[Table] Example 2 Polyurethane adhesives were prepared using the formulations shown in Experiment Nos. 7 to 13 in Table 2 below (the content of Compound A was varied). A portion of each prepared solution was taken and bonded in the same manner as in Example 1, and the strength measurement results are shown in Table 2.

[Table] Example 3 A portion of the prepared liquids shown in Experiment Nos. 1 and 2 was taken and applied to various adhesives shown in Experiment Nos. 14 to 25 in Table 3 and adhered. After gluing and curing at room temperature for one week,
Bell peel strength was measured at a temperature of 25°C and the results are shown in Table 3.

[Table] Example 4 10 parts by weight of Compound A obtained in Reference Example and 90 parts by weight of Polyol G-700 were placed in a 200 ml four-neck separable flask, and while blowing nitrogen gas,
After stirring and mixing at room temperature for 10 minutes, the mixture was left standing at room temperature overnight to prepare a mixed solution. 50 parts by weight of this mixed solution and polyisocyanate (Sumijiur E-21-1)
A polyurethane adhesive was prepared by stirring 50 parts by weight in a beaker at room temperature for 5 minutes. Then, take a part of this prepared solution and add it to a 0.3 mm thick iron piece (JIS
G314SPCC-SB) was applied to two sheets and adhered. After adhesion and curing for one week, the T peel strength was measured at a temperature of 25°C, and a value of 8.7 kg/25 mm was obtained.
The state of failure of the adhesive surface was cohesive failure. Example 5 Compound A obtained in Reference Example was dissolved in ethyl acetate to prepare a 1% by weight solution, which was used as a primer. The above primer was brushed onto two pieces of iron (JIS G314SPCC-SB) with a thickness of 0.3 mm and dried. The following two-component polyurethane adhesive liquids A and B were mixed at a weight ratio of A/B = 1.6/1.0, and the mixed liquid was applied to the primer-coated surfaces of the two iron pieces and bonded together. . After curing for one week at room temperature after adhesion, T-peel strength was measured. Further, for comparison, an iron piece of the same quality as above was adhered in the same manner using the above adhesive without performing primer treatment, and the T-peel strength was measured. Urethane adhesive liquid A used: Polyiricyanate (Sumijiur E-
21-1) Liquid B: Polyol (ADEKA Polyether G-
700) Results of T peel strength: Value of primer-treated product of the present invention, 9.3kg/25mm (Comparative example) Value of unprimed product, 0.5kg/25mm

Claims (1)

[Scope of Claims] 1. A curable material comprising (A) at least one polyisocyanate, (B) at least one active hydrogen compound, and (C) a compound represented by the following general formula (1). Polyurethane adhesive. General formula (1): (However, in the formula, R is H or a CH ₃ group, and R ₁
is a group containing at least one SH group in the molecule, R ₂ is H or R ₁ group, X is a group containing an acidic phosphoric acid group, and n is an integer of 2 to 20. ) 2. The curable polyurethane adhesive according to claim 1, wherein the compound represented by formula (1) is dissolved in an active hydrogen compound. 3. The curable polyurethane adhesive according to claim 1, wherein the compound represented by formula (1) is dissolved in a volatile solvent.