JPH0726070B2 - Primer composition - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a plummer composition, and more specifically, to the adhesiveness, heat resistance and water resistance of a polyurethane adhesive or a polyurethane sealant used for plastics or metals. And a primer composition for improving weather resistance.

[Prior Art] Conventionally, in the case of adhering a plastic or metal using a polyurethane-based adhesive, a primer composition is applied as a pretreatment agent for adhesion to the surface of the adherend plastic or metal in order to obtain higher adhesive strength. Applying things.

Examples of the primer composition used for this purpose include a solution consisting of an isocyanate compound alone, a polyether polyol having 2 to 3 hydroxyl groups such as polyethylene glycol or a polyester polyol having 2 to 3 hydroxyl groups, and an isocyanate compound. There is a prepolymer solution obtained by the addition reaction with and the like, and the solution is applied to the surface of an adherend with a brush or the like, dried, and then a polyurethane adhesive or sealant is applied.

[Problems to be Solved by the Invention] When a polyurethane-based adhesive is applied using a conventional primer composition, satisfactory performance can be obtained with the initial adhesive strength, but the performance deteriorates over time and heat resistance is particularly high. In terms of durability, water resistance and weather resistance, satisfactory performance was not always obtained. Furthermore, when applied as a primer for a soft adhesive having a Young's modulus after curing of 200 kg / cm ² or less, the conventional primer composition has a problem that interface breakage is likely to occur.

Further, the same problem occurs in the case of polyurethane type sealant.

[Means for Solving Problems] In order to solve the problems in the first aspect of the present invention, (A) a polyol compound having an average number of hydroxyl groups of 4 or more (hereinafter, simply referred to as “specific polyol”), (B) isocyanate An isocyanate compound having two or more nato groups (hereinafter, simply referred to as “isocyanate”), a (C) catalyst, and (D) an organic solvent inert to the above (B) component, There is provided a primer composition characterized in that the component (A) and the component (B) are contained in an amount ratio in which the number of all the isocyanate groups in the component (B) exceeds the number of all the hydroxyl groups in (A). It is a thing.

If the average number of hydroxyl groups of the polyol compound used in the primer composition is less than 4, the problems of the conventional primer composition, particularly the adhesiveness when used as a primer for soft adhesives and sealants cannot be improved.

The specific polyol in the present invention has an average number of hydroxyl groups of 5 to 33.
However, as long as the average number of hydroxyl groups is 4 or more, the specific polyol in the primer composition may contain a polyol having less than 4 hydroxyl groups.

Specific polyols that can be used in the present invention include, for example, polyol compounds based on ethylenediamine, sucrose, sucrose amine, sorbitol, sorbitol amine, epoxy-modified resin and lactone-modified epoxy resin. The specific examples are shown in Table 1.

In addition to the above, N, N, N ', N'-tetrakis (2-hydroxypropyl) ethylenediamine and N, N, N', N '
Examples thereof include a polyol compound obtained by adding propylene oxide to tetrakis (2-hydroxypropyl) ethylenediamine.

In the present invention, the average number of hydroxyl groups (pieces) is a value calculated by the following formula from the molecular weight of the polyol compound and the average hydroxyl value, and the average hydroxyl value (KOHmg / g) is JIS K1557.
It is a value measured based on.

(Average hydroxyl value / 1000) × (17/56) × (molecular weight of polyol compound) ÷ 17 = average number of hydroxyl groups (number) The isocyanate used in the present invention has two or more isocyanate groups, preferably 3 or more. It is an isocyanate compound having one or more, and is preferably an isocyanate compound having an isocyanate group content of 15% by weight or more in one molecule, for example, 4,4′-diphenylmethane diisocyanate (MDI), carbodiimide modification of MDI. , Triphenylmethane triisocyanate, tris (p-isocyanatophenyl) thiophosphate, trade name Sumidule L, Sumidule IL and Sumidule RU (all manufactured by Sumitomo Bayer Urethane Co.) , Hexamethylene diisocyanate, lysine diisocyanate and trade name (Manufactured by Sumitomo Bayer Urethane Co., Ltd.) and other aliphatic isocyanate compounds, 4,4'-dicyclohexylmethane diisocyanate, isophorone diisocyanate, isopropylidene bis (4-cyclohexyl isocyanate), trade name Desmodur KL- 2444, Desmodur Z-4370, Desmodur R and Desmodur RF (all manufactured by Sumitomo Bayer Urethane Co., Ltd.), alicyclic isocyanates such as hydrogenated xylylene diisocyanate, and the like can be mentioned.

Among the above-mentioned isocyanates, aromatic ones are preferable from the viewpoint of adhesiveness and workability such as film formation after application to an adherend, and especially desmodur R and desmodur R
F, polymeric MDI, etc. are preferred.

The above isocyanates can be used in combination of two or more,
Even when two or more isocyanate compounds are used in combination, the total isocyanate group content is preferably 15% by weight or more based on the total weight of the isocyanate compound. 15 isocyanate groups
It is also possible to use an isocyanate of less than wt% together.

Specific examples of the isocyanate having an isocyanate group content of less than 15% by weight in one molecule include Sumidule E21-
2. Death Module E22, Death Module E41, Sumidule DL101 (all manufactured by Sumitomo Bayer Urethane Co., Ltd.).

15 isocyanate groups based on the total weight of the isocyanate.
If it is less than wt%, it is difficult to increase the concentration of free isocyanate groups in the primer composition to the range where good performance is obtained, and the film-forming ability of the primer composition after application to an adherend is poor. Become.

In the present invention, a catalyst is used to promote the reaction between the hydroxyl group of the specific polyol and the isocyanate group of the isocyanate.

Specific examples of the catalyst include organic compounds such as zinc stearate, dibutyltin dilaurate, tin octylate, copper acetylacetonate, iron acetylacetonate, nickel acetylacetonate, manganese acetylacetonate, zinc acetylacetonate, and cobalt acetylacetonate. Metal compounds, 2-methyltriethylenediamine,
Triethylenediamine, N, N, N'-trimethylaminoethylethanolamine, N, N-dimethylaminoethylmorpholine, N, N-dimethylpiperazine, 1,8-diazabicyclo [5.4.0] undecene-7 ( Examples thereof include amines such as DBU), phenol salts of DBU, 2-ethylhexanoate of DBU, amine salts such as oleate of DBU, and mixtures thereof.

The primer composition of the present invention is prepared by blending a specific polyol, an isocyanate and a catalyst.

At this time, when the total weight of the isocyanate group is less than 10% by weight of the primer composition, the problem with the conventional primer composition having low storage stability cannot be improved.

Further, it is usually sufficient that the specific polyol is blended so that all the hydroxyl groups in the specific polyol are stoichiometrically less than all the isocyanate groups in the isocyanate compound.

When the polyol compound or isocyanate is a solid,
You may melt | dissolve in the solvent inactive to the isocyanate group for primer compositions mentioned later beforehand, and may mix it.

Further, the catalyst is usually added in an amount of 0.001 to 5 parts by weight based on 10 parts by weight of the mixture of the specific polyol and the isocyanate.
If the catalyst is used in an amount of more than 5 parts by weight, the storage stability of the primer composition will decrease.

The primer composition of the present invention is usually used by dissolving it in an organic solvent which is inactive with respect to an isocyanate group, and applying it to an adherend by brush, spray or dipping.

Specific examples of the solvent include ketones such as Aston and methyl ethyl ketone; aromatic hydrocarbons such as toluene and xylene; esters such as ethyl acetate and butyl acetate; halogenated hydrocarbons such as methylene chloride and trichloromethane; Examples thereof include a mixture thereof, and among them, methyl ethyl ketone and methylene chloride are preferable because the drying time after coating is short and the surface of the adherend is also washed.

The concentration of the primer composition of the present invention in these solvents is preferably 0.01 to 30% by weight, more preferably 2 to 20% by weight from the viewpoint of workability such as coating on the surface of an adherend.

If desired, the primer composition of the present invention may be blended with optional components depending on the purpose of use so long as the original purpose is not impaired. Examples of these optional components include pigments, dyes, antioxidants, plasticizers, fillers and tackifiers.

The primer composition of the present invention enhances the adhesive strength of a polyurethane-based adhesive or sealant. Therefore, the adherend is intended to be a material adhered with a polyurethane-based adhesive or sealant. Examples of adherends include metals such as steel plates, ABS resin, glass fiber reinforced polyester (FRP), and the like.

Suitable polyurethane-based adhesives or sealants for use with the primer composition of the present invention include, for example, MIGH.
TYGRIP 6600/6647, 7100/7125, MIGHTYSEAL1000 / 105
0, 1100/1135 (both manufactured by Japan Synthetic Rubber Co., Ltd.) and the like.

When the adherend is adhered using the primer composition of the present invention, first, the primer composition solution is applied to the surface of the adherend and usually dried at room temperature. Then, a polyurethane-based adhesive is applied onto the coating film of the primer composition, and another adherend similarly treated with the primer composition is overlaid to complete the adhesion.

Also, when the adherend is sealed using the primer composition of the present invention, it is applied in the same manner as the adhesive.

[Examples] The present invention will be described below with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. In the following examples, parts are parts by weight and% are% by weight, unless otherwise specified.

Example 1 1.2 parts of a 60% toluene solution of an epoxy-modified resin having a molecular weight of 10,000 and an average number of hydroxyl groups of 33 (hydroxyl value 183) (Asahi Denka Kogyo Co., Ltd., trade name FP-6021), tris (p-isocyanatophenyl) thiophosphite. (The content of the isocyanate group in the molecule is 27% (This content is the value obtained by back titration of di-n-butylamine. The same applies hereinafter.) 20% methylene chloride solution (Sumitomo Bayer Urethane Co., trade name Desmodur RF) 17 parts, and 2-methyltriethylenediamine as a catalyst (manufactured by Sankyo Air Products Co.,
0.052 parts (trade name: Methyl-DABCO) was mixed to obtain a primer composition solution.

The content of the isocyanato group of the primer composition in the solution is
22%.

20 parts of this primer composition solution was added to methylene chloride 100
To obtain a primer composition solution containing 3.8% of the primer composition.

Comparative Example 1 Polyether polyol having a molecular weight of 2,000 and an average number of hydroxyl groups of 2 (hydroxyl value of 56) (manufactured by Asahi Denka Co., Ltd., trade name P-2,00
0) 1.0 part, 15.6 of the isocyanate solution used in Example 1
And 0.052 of the same compound as in Example 1 as a catalyst.
A primer composition solution was obtained from the part. The isocyanate group content of the primer composition in the solution is 19%.

18 parts of this primer composition solution was added to 100 parts of methylene chloride.
To obtain a primer composition solution containing 3.8% of the primer composition.

Example 2 Sucrose-based polyol having an average number of hydroxyl groups of 5.5 (hydroxyl number of 450) (Asahi Glass Co., Ltd., trade name: Exenol 50S)
1.5 parts, 68 parts of the isocyanate solution used in Example 1, 1,8-diazabicyclo [5.4.0] undecene-7 as a catalyst
Oleate (manufactured by San Abbott, trade name SA # 106)
A primer composition solution was obtained from 0.03 part and 0.03 part of trade name Oil Orange SS (manufactured by Tokyo Kasei) as a dye. Isocyanate group content of the primer composition in the solution is
21%.

230 parts of this primer composition solution was added to methyl ethyl ketone 1
It was diluted with 00 parts to obtain a primer composition solution containing 15% of the primer composition.

Example 3 Crude 4,4-jephenylmethane diisocyanate (Sumitomo Bayer Urethane Co., Sumidule 44V20) 100
Part and polyether diol (Asahi Denka Kogyo KK, p-700) 1
80 parts were reacted in a flask at 90 ° C for 2 hours to obtain a polyisocyanate compound. The content of isocyanate groups in this compound was 12%.

100 parts of the above polyisocyanate compound and 500 parts of a 20% methylene chloride solution of triphenylmethane triisocyanate having three isocyanate groups and 35% (manufactured by Sumitomo Bayer Urethane Co., Ltd., Desmodur R) are mixed, An isocyanate mixture solution was obtained. The isocyanate group of the isocyanate mixture in this solution is 24%.
Next, 5 parts of a 70% triene solution of an epoxy-modified resin-based polyol having a molecular weight of 1,000 and an average number of hydroxyl groups of 6 (hydroxyl value 314) (trade name: EP-6020, manufactured by Asahi Denka Co., Ltd.) and 64 parts of the above isocyanate mixture solution, a catalyst. As dibutyltin laurate (manufactured by ADEKA ARGUS CORPORATION) as Example 3 and Example 2
A primer composition solution was obtained from 0.2 part of the dye used in.
The isocyanate group content of the primer composition in the solution is 17%.

16 parts of this primer composition solution was added to 100 parts of methylene chloride.
To obtain a primer composition solution containing 50% of the primer composition.

Adhesion performance test Three types of adherends (25 mm x 100 mm FRP, ABS and steel plate, thicknesses of FRP and A were obtained by degreasing the primer composition solutions of Examples 1 to 3 and Comparative Example 1 in advance with methylene chloride.
Two pieces were selected from the combinations shown in Tables 2 to 5 from BS of 3 mm and steel plate of 1.6 mm), and each adhesive portion was coated with a brush and air dried for 15 minutes. Next, apply the adhesives or sealants noted in Tables 2-5 to the primer-coated surfaces, and bond them so that the overlap becomes 2.5 x 12.5 mm.
Cured under conditions as noted in 5.

After curing, tensile adhesive strength was measured with Autograph DSS-2000 (manufactured by Shimadzu Corporation) at a chuck distance of 11.0 cm and a tensile speed of 5 mm / min.

The initial adhesive strength, water deterioration resistance, moisture deterioration resistance, heat deterioration resistance and hot strength are tensile adhesion strength measured as described below.

1) Initial adhesive strength After being cured under a predetermined curing condition and the test piece reaches room temperature,
The tensile adhesive strength was measured at room temperature.

2) Water deterioration resistance, humidity deterioration resistance, heat deterioration resistance After curing under predetermined curing conditions and the test piece is at room temperature,
It was exposed to the conditions noted in Tables 2-5. Then, the test piece was taken out and returned to room temperature, and then the tensile adhesive strength was measured.

3) Hot strength After curing under predetermined curing conditions and the test piece reaches room temperature,
Tensile bond strength was measured at the temperatures noted in Tables 2-5.

Further, material destruction, cohesive failure and interface failure are the following failures.

Destruction of material: Destruction in which the material of the adherend is destroyed earlier than the material of the adherend because the adhesive strength of the adhered part is stronger than the material of the adherend. Cohesive failure: The adhesive part is destroyed, but the adhesive is the surface Destruction that remains in the interface Interfacial fracture: Destruction at the interface between the primer composition and the adherend or the interface between the primer composition and the adhesive when the adhesive part is destroyed Note 1) A polyurethane adhesive (manufactured by Japan Synthetic Rubber Co., Ltd., trade name; MIGHTYGRIP6600 / 6647) having the following physical properties is used.

Elongation at break; 100% Young's modulus; 1000 kg / cm ² Shore D hardness; 70 Break strength; 250 kg / cm ² Curing condition; Leave at 20 ° C. for 3 days after bonding 2) FRP material destruction.

3) Breakage at the steel plate / primer interface.

4) Failure at the interface between the steel plate and the adhesive.

Note 1) A soft polyurethane one-component sealant with the following physical properties is used (Nippon Synthetic Rubber Co., Ltd., trade name; MIGHTYGRI
P1100 / 1135) Elongation at break; 400% Young's modulus; 40kg / cm ² Breaking strength; 60kg / cm ² Curing condition; Leave at 20 ° C for 3 days after bonding 2) Cohesive failure of sealant.

3) A mixture of cohesive failure of the sealant and failure at the interface between FRP and the primer.

4) Destruction at the interface between FRP and the primer.

Note 1) A soft polyurethane adhesive with the following physical properties is used.

Breaking elongation; 130% Young's modulus; 60kg / cm ² Breaking strength; 60kg / cm ² Shore D curing; 35 Curing conditions: 20 ° C for 1 hour after adhesion, then 120 ° C for 1 hour 2) FRP material destruction and adhesion Destruction mixed with cohesive destruction of agents.

3) Material destruction of FRP.

4) Cohesive failure of the adhesive.

Note 1) The same adhesive as in Table 2 was used.

Curing conditions: 20 ° C for 2 hours after adhesion, then 140 ° C for 1 hour 2) FRP material destruction.

3) Destruction in which material destruction of FRP and cohesive destruction of adhesive are mixed.

4) Cohesive failure of the adhesive.

[Advantages of the Invention] The present invention provides a primer composition that solves the problems of the primer composition conventionally used as a primer for polyurethane adhesives or sealants, and exhibits the following effects. .

(1) When used as a primer for a polyurethane-based adhesive or sealant, the conventional primer composition was liable to cause interface fracture in heat resistance, water resistance and weather resistance tests, but when the primer composition of the present invention was used, The adhesive strength is increased up to the destruction of the material of the adherend or the cohesive failure of the adhesive or sealant, the strength is remarkably improved, and excellent adhesiveness or sealability is obtained.

(2) Even when used as a primer for a soft polyurethane adhesive or sealant having a Young's modulus after curing of 200 kg / cm ² or less, interface destruction does not occur, and material destruction of the adherend or adhesive or sealant Adhesion is improved up to cohesive failure.

Claims (4)

[Claims] 1. A polyol compound having (A) an average number of hydroxyl groups of 4 or more, (B) an isocyanate compound having two or more isocyanate groups, (C) a catalyst, and (D) the above component (B). It is composed of an inert organic solvent, and the components (A) and (B) are contained in an amount ratio in which the total number of isocyanate groups in the component (B) exceeds the total number of hydroxyl groups in the component (A). A primer composition comprising: 2. A method according to claim 1, wherein the (B) isocyanate compound containing two or more isocyanate groups is an isocyanate compound having 15% by weight or more of isocyanate groups in one molecule. The lymer composition as set forth in paragraph 1. 3. The primer composition according to claim 1 or 2, which comprises 10% by weight or more of (B) an isocyanate compound containing two or more isocyanate groups. 4. The primer composition according to claim 1, 2 or 3 applied to a polyurethane adhesive and a polyurethane sealant.