JPS63152685A - Primer composition - Google Patents

Abstract

PURPOSE:To obtain a primer composition effective in improving the adhesivity of a polyurethane adhesive or sealant for plastics, metals, etc., by compounding a specific polyol compound with a specific polyisocyanate compound and a catalyst. CONSTITUTION:The objective primer composition can be produced by compounding (A) a polyol compound having an average hydroxyl group number of >=4 and preferably based on an epoxy-modified resin with (B) a polyisocyanate compound having >=2 (preferably >=3 and >=15wt%) isocyanate groups directly bonded to an aliphatic group and (C) a catalyst selected from zinc stearate, dibutyltin dilaurate, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a primer composition, and more particularly, when it is used as a polyurethane adhesive or a polyurethane sealant for adhesion or sealing of plastics, metals, etc. The present invention relates to a primer composition suitably used to improve the adhesion properties of these materials.

[Conventional technology]

Generally, when bonding plastics or metals using a polyurethane adhesive, a primer composition is applied to the surface of the adherend as a pre-adhesion treatment in order to obtain higher adhesive strength.

Primer compositions used for this purpose conventionally include those consisting of a solution of an isocyanate compound alone, polyether polyols having 2 to 3 hydroxyl groups,
For example, those consisting of a prepolymer solution obtained from the addition reaction of polyethylene glycol or a polyester polyol having 2 to 3 hydroxyl groups and an isocyanate compound are known.

[Problem that the invention seeks to solve]

However, when a conventional primer composition is used and a polyurethane adhesive is applied after its application, even if a satisfactory adhesive force is obtained for a relatively short initial period after application, it may deteriorate over time. The adhesion force decreased, and a satisfactory adhesion state could not be obtained over a long period of time, especially with regard to heat resistance, water resistance, and moisture resistance. moreover,
When applying a soft adhesive whose Young's modulus after curing is 200 kg/c++” or less,
Pretreatment with conventional primer compositions has the problem that a sufficient primer effect cannot be obtained, resulting in low adhesion and interfacial destruction caused by weak force.

Furthermore, in conventional primer compositions for polyurethane adhesives, in order to obtain good adhesive strength, isocyanate compounds in which isocyanate groups are directly bonded to aromatic groups are used as component isocyanate compounds. Therefore, in the case of a product in which the surface coated with the primer composition is exposed to the atmosphere, there is a problem that the primer composition becomes colored in the areas exposed to the atmosphere, resulting in poor appearance.

The above-mentioned problems also exist in treatments with primer compositions for polyurethane sealants.

Means for Solving Problems c] The present invention has been made to solve the above problems, and comprises a polyol compound (hereinafter simply referred to as "polyol") having an average number of hydroxyl groups of 4 or more; , a polyisocyanate compound having two or more isocyanate groups directly bonded to an aliphatic group (hereinafter simply referred to as "polyisocyanate"),
The present invention provides a primer composition characterized by comprising a catalyst.

In the above, if the average number of hydroxyl groups of the polyol used is less than 4, the problems of conventional primer compositions, especially when used as a primer for soft adhesives and sealants, cannot be improved.

The polyol used has an average number of hydroxyl groups of 4 or more, preferably 5 to 33, but if the condition that the average number of hydroxyl groups is 4 or more is satisfied, polyols with a hydroxyl group of less than 4 can be used. may be included.

Examples of the polyol used in the present invention include polyols based on ethylenediamine, sucrose, sucrose amine, sorbitol, sorbitol amine, epoxo-modified fat, lactone-modified epoxo resin, etc. Specific examples thereof include: As shown in Table 7A1.

In addition to the above, N,N,N',N'-tetrakis(2-hydroxypropyl)ethylenediamine,
Polyols obtained by adding propylene oxide to N, N, N', N'-tetrakis(2-hydroxypropyl)ethylenediamine can also be mentioned.

Among these, it is particularly preferable to use polyols based on epoxy-modified resins because they can improve the adhesive strength of the primer composition itself and provide good storage stability.

In addition, in the present invention, the "average number of hydroxyl groups" is a value calculated by the following formula from the molecular weight of the polyol and the average hydroxyl value, and the average hydroxyl value (in OHmg/g) is determined according to JIS
This is a value measured based on K1557.

Average number of hydroxyl groups (pieces) = (average hydroxyl value/1000) x (17156) x
(Molecular weight of polyol compound) ÷ 17 The polyisocyanate used in the present invention has two or more, preferably three or more, isocyanate groups directly bonded to an aliphatic group, and furthermore, the isocyanate group content in one molecule is Preferably, the polyisocyanate is 15% by weight or more.

Such polyisocyanates include, for example, hexamethylene diisocyanate, isophorone diisocyanate, isopropylidene bis(4-cyclohexyl isocyanate), hydrogenated xylylene diisocyanate and their 7-duct forms, biuret conjugates, isocyanurate conjugates, and the like. Product name: "Sumidur N", "Sumidur N-3200J, r Sumidur IIT"
J, r Desmodule N-32504, r Desmodule Z-4370J, r 5Btl Isocyanate 0827j, rsBU Isoocyanate 0828J
(All of the above are manufactured by Sumitomo Bayer Urethane Co., Ltd.), "Coronate" ILJ (manufactured by Nippon Polyurethane Co., Ltd.), Mytic NY, -T-18J (manufactured by Mitsubishi Chemical Industries, Ltd.) and other polyisocyanates can be mentioned.

Among the above polyisocyanates, especially [Sumidur H
TJ, "Sumidur N" and the like are preferable in terms of adhesiveness and workability such as film forming properties after coating on an adherend.

In the present invention, it is necessary that the isocyanate group of the polyisocyanate is directly bonded to the aliphatic group,
Direct bonding to groups other than aliphatic groups, such as aromatic groups, causes problems such as coloring of the resulting primer composition when exposed to the atmosphere.

In the present invention, two or more types of polyisocyanates can also be used in combination. Even when two or more types of polyisocyanates are used together, the ratio of all isocyanate groups to the total weight of the polyisocyanate is 1.
The content is preferably 5% by weight or more, and if such conditions are met, a polyisocyanate containing less than 15% by weight of isocyanate groups in one molecule may also be used.

If the proportion of isocyanate groups based on the total weight of the polyisocyanate is less than 15% by weight, the proportion of active isocyanate groups in the resulting primer composition will be small, making it impossible to obtain a good primer effect, and also making it difficult to apply the primer composition to the adherend. There is a risk that the film forming ability will be inferior.

Further, in the present invention, the ratio of the total weight of active isocyanate groups by the polyisocyanate is 1 to the total weight of the polyol and polyisocyanate in the composition.
The content is preferably 0% by weight or more, thereby making it possible to obtain a primer composition with good storage stability.

The term "active isocyanate group" as used herein refers to the isocyanate group remaining after subtracting the number of equivalents of the hydroxyl group of the polyol from the isocyanate group of the polyisocyanate.

When the polyol or polyisocyanate actually used is a solid, the polyol or polyisocyanate is dissolved in a solvent for the primer composition that is inert to isocyanate groups (an example of which will be described later). The solutions may be mixed.

In the primer composition of the present invention, a catalyst is used to promote the reaction between the hydroxyl groups of the polyol and the isocyanate groups of the polyisocyanate.

Specific examples of this catalyst include, for example, zinc stearate,
Dibutyltin dilaurate, tin octylate, copper acetylacetonate, iron acetylacetonate, nickel acetylacetonate, manganese acetylacetonate,
Organometallic compounds such as zinc acetylacetonate and cobalt acetylacetonate, 2-methyltriethylenediamine, triethylenediamine, N,N,N'-)limethylaminoethylethanolamine, N,N-dimethylaminoethylmorpholine, Amines such as N,N-dimethylpiperazine, 1,8-diaza-bicyclo(5,4,0)undecene-7 (hereinafter referred to as rDBUJ), D
Examples include phenol salts of Btl, 2-ethylhexanoate of DBυ, amine salts such as oleic hydrochloride of OB[I, formate of 080, and mixtures thereof.

The proportion of the catalyst used is usually 0.001 to 100 parts by weight of the mixture of polyol and polyisocyanate.
If the amount of catalyst used exceeds 5 parts by weight, the storage stability of the primer composition tends to decrease.

The primer composition of the present invention is usually used by dissolving it in an organic solvent inert to isocyanate groups and applying the resulting solution onto an adherend by means such as brushing, spraying, or dipping.

Specific examples of solvents used here include ketones such as acetone and methyl ethyl ketone; aromatic hydrocarbons such as toluene and xylene; esters such as ethyl acetate and butyl acetate; methylene chloride, etc.
Mention may be made of halogenated hydrocarbons such as lychloroethane; and mixtures thereof. Among these, methyl ethyl ketone or methylene chloride is preferable because it requires a short drying time after application and also has a cleaning effect on the surface of the adherend.

Such a solvent is preferably used in a proportion such that the concentration of the primer composition of the present invention in the obtained primer solution is 0.01 to 30% by weight, particularly 2 to 20% by weight, when applied to the surface of an adherend, etc. preferred in terms of workability.

If necessary, optional components depending on the purpose of use may be added to the primer composition of the present invention within a range that does not impair the original purpose.

Examples of these optional components include pigments, dyes, anti-aging agents, plasticizers, fillers, tackifiers, reaction accelerators, and the like.

Furthermore, the primer composition of the present invention may contain a urethane prepolymer to improve drying properties during application or to improve adhesion to certain plastics.
It is also possible to add property improvers such as acrylonitrile-styrene copolymer and vinyl chloride-vinyl acetate copolymer. Such property improvers are added in a proportion of 0 to 100 parts based on 100 parts of the total weight of polyol and polyisocyanate.

Examples of adherends for the primer composition of the present invention include metals such as steel plates, ABS resins, and glass fiber-reinforced polyester resins called rFRP.

Specific examples of polyurethane adhesives or sealants that exhibit excellent primer effects with the primer composition of the present invention include, for example, the product name rMIGHTYGRI.
P 6600/6647J, rM[GHTYGRIP
7100/7125J, rMIGHTYsEAL 10
00/1050J and rMIGHTYsEAL 11
00/1127J (all manufactured by Japan Synthetic Rubber Co., Ltd.).

When adhering adherends using the primer composition of the present invention and a polyurethane adhesive, first apply the primer composition solution of the present invention to the surface of one adherend,
Usually, it is dried at room temperature, then a polyurethane adhesive is applied on top of the coated film of the primer composition, and the other adherend, which has been similarly treated with the primer composition, is overlaid and pressure-bonded. The same applies when sealing an adherend.

〔Example〕

Examples of the present invention will be described below, but the present invention is not limited thereto.

In addition, in the following, "parts" represent parts by weight, and "%" represent weight %.

Example 1 Polyol> Molecular weight 10,000, average number of hydroxyl groups 33 (hydroxyl value 18
3) 60% toluene solution of epoxy modified resin-based polyol rEP-6021J (manufactured by Asahi Denka Kogyo Co., Ltd.)
0.92 parts <Polyisocyanate> 75% ethyl acetate solution of an adduct of hexamethylene diisocyanate (content of isocyanate groups in the molecule: 16.7%) [SumiDur HT J manufactured by Sumitomo Bayer AG] 4.59 parts catalyst > Dibutyltin dilaurate 0.004 parts <Solvent> Methylene chloride 94.5 parts or more of the materials were mixed to prepare a primer composition solution containing the primer composition at a ratio of 4.0%. The ratio of active isocyanate groups to the total weight of polyol and polyisocyanate in this τ solution is 12.5%.

Example 2 In Example 1, the proportion of solvent methylene chloride was changed to 7.
The primer composition was prepared in the same manner as in Example 1, except that the primer composition was changed to 4.3 parts, and 20.2 parts of a 5% solution of vinyl chloride-vinyl acetate copolymer in methyl ethyl ketone was added and mixed. A primer composition solution containing the following proportions was prepared. The ratio of active isocyanate groups to the total weight of polyol and polyisocyanate in this solution was 12.5% as in Example 1.

Example 3 Instead of 4.59 parts of the adduct solution of hexamethylene diisocyanate in Example 1, 75% cellosolve of a biuret conjugate of hexamethylene diisocyanate (content of isocyanate groups in the molecule: 22.0%) and xylene (1 1) A primer composition solution containing the primer composition at a ratio of 4.2% in the same manner as in Example 1 except that 3.48 parts of the mixed solution "Sumidur N" (manufactured by Sumitomo Bayer Urethane) was used. was prepared. The proportion of active isocyanate groups based on the total weight of polyol and polyisocyanate in this solution is 14.9%.

Example 4 In Example 1, the proportion of solvent methylene chloride was changed to 7.
A primer composition was prepared in the same manner as in Example 1 except that 20.2 parts of a 5% methyl ethyl ketone solution of a urethane polymer with terminal hydroxyl groups (hydroxyl group content 0.1%) was added and mixed. A primer composition solution containing 5.0% of the following was prepared. The ratio of active isocyanate groups to the total weight of polyol and polyisocyanate in this solution was 12.5% as in Example 1.
It is.

Example 5 A primer composition solution containing the primer composition at a rate of 6.1% was prepared in the same manner as in Example 1 except that the proportion of polyol in Example 1 was changed to 4.9 parts. The proportion of active isocyanate groups to the total weight of polyol and polyisocyanate in this solution is:
It is 9.0%.

Comparative Example 1 Instead of the polyol in Example 1, molecular weight 2.0
The primer composition was prepared in the same manner as in Example 1, except that 1.18 parts of Efsenol 2020 J (manufactured by Asahi Glass Co., Ltd.), a polyether polyol with an average number of hydroxyl groups of 2 (hydroxyl value 56) and an average number of hydroxyl groups of 2 (hydroxyl value 56) was used. % of the primer composition was prepared.

Comparative Example 2 In Example 1, the proportion of polyol was changed to 1.2 parts, and instead of the adduct of hexamethylene diisocyanate, tris(p-isocyanate phenyl) thiophosphate (content of isocyanate groups in the molecule was 27%).
A primer composition solution containing the primer composition at a ratio of 3.79A was prepared using 17 parts of a 20% methylene chloride solution.

Comparative Example 3 Polyether diol "Efsenol 10" with an average molecular weight of 1,000 and an average number of hydroxyl groups of 2 (hydroxyl value 112)
100 parts of 20J (manufactured by Asahi Glass Co., Ltd.) and 50 parts of hexamethylene diisocyanate Desmodur (J (manufactured by Sumitomo Bayer Urethane) were reacted at a temperature of 80°C for 5 hours to produce a urethane prepolymer having an isocyanate group at the molecular end. The average number of isocyanate groups in the molecule of this polyisocyanate prepolymer is 11.
It is 1%.

A primer composition of 9.7 parts was prepared in the same manner as in Example 1 except that 9.6 parts of the above polyisocyanate prepolymer was used instead of the polyisocyanate in Example 1.
A primer composition/8 solution containing %.

Test example [Adhesive performance test] Each has a size of 25 m + w x 100 mm, and a steel plate with a thickness of 3 mm (1') FRP and ABS resin with a FJ of 3 mm and a thickness of 1.6 am is attached. Two of these three types of adherend samples were selected as shown in the tables below, and after degreasing them with methylene chloride in advance, the samples obtained in the above Examples and Comparative Examples were prepared as body samples. Primer composition? Each of the 8 liquids,
Each adhesive was applied with a brush to a 2.5 mm x 12.5 mm adhesive area on the adherend sample, air-dried for 15 minutes, and then the adhesive or adhesive listed in the explanations in each table below was applied to the primer-applied surface. The two coated parts were overlapped and bonded together, and cured under the conditions described in the explanations in each table below.

After curing, using Autograph DSS-2000J (manufactured by Shimabara Seisakusho Co., Ltd.), the distance between the chucks was 11.0 cm,
Tensile adhesive strength was measured at a tensile speed of 517 minutes.

The results are shown in Tables 2 to 4 along with the state of destruction.

Initial adhesive strength, water deterioration resistance, moisture deterioration resistance, heat deterioration resistance, and hot strength are expressed as tensile adhesive strength measured under the following conditions.

Tensile adhesive strength measured at room temperature after curing under specified curing conditions.

Water damage, moisture damage resistance, U-curing resistance Tensile adhesive strength measured after curing under specified curing conditions, processing according to the following, and then taking out the test piece and returning it to room temperature.

Water deterioration resistance (1): Immersed in 40°C warm water for 20 days Water deterioration resistance (2): Immersed in 60°C warm water for 20 days Moisture deterioration resistance: 20 days in an environment of 50°C temperature and 95% relative humidity Heat deterioration resistance after being left for one day: left in an environment with a temperature of 80°C for 20 days ■ Cured under the specified curing conditions, preheated or precooled at the temperature shown in the table for 30 minutes, and then cured at that temperature in the evening. Tensile adhesive strength.

Furthermore, material failure, cohesive failure, and interfacial failure are the following types of failure.

Material failure: The adhesive strength of the adhesive part is stronger than the strength of the material of the adhered object, so the material of the adhered object breaks before the adhesive part.Cohesive failure: The adhesive part breaks, but the adhesive Destruction remaining on the adhesive surface Interfacial destruction: Destruction in which the interface between the primer composition and the adhered object or the primer composition and the adhesive is destroyed when the adhesive part is destroyed.Explanation of Table 2Table 2 shows the following physical property values. polyurethane adhesive rMI
Adhere the adherend sample using GHTYGRIP 6600/6647J (manufactured by Japan Synthetic Rubber Co., Ltd.) at a temperature of 20°C.
The initial adhesion strength and fracture state when the adhesive was left to cure for 3 days are shown.

"Former IJTYGRIP 6600/6647" Breaking elongation: 100% Young's modulus: 1000 kg/cm
2 Shore D Hardness Near 0 Breaking Hardness 2250 kg/cm” *Alpha vent in the state of fracture in the table shows the following.

A: Material destruction of FRP.

B: Fracture at the interface between the steel plate and the primer.

C: Destruction at the interface between FRP and primer.

D: ABS material destruction.

E: Broken at the interface between ABS and primer.

Table 3 shows the soft polyurethane two-component sealant "IGHTYSEAL 1100/1127" with the following physical properties.
J (manufactured by Japan Synthetic Rubber Co., Ltd.) to adhere an adherend sample and leave it at a temperature of 20°C for 3 days to harden. show.

“Former GHTYSEAL 1100/1127J Breaking elongation 8150% Young’s modulus: 40 kg/cm!
Breaking strength: 60 kg/cmz The letters of the breaking state in this table indicate the following.

Cohesive failure of A-nijirant.

A failure that is a mixture of cohesive failure of B-Nigilant and failure at the interface between FRP and primer.

C: Destruction at the interface between FRP and primer.

Table 4 shows the initial adhesion when adherend samples were bonded using the same adhesive as in Table 2 and left to harden for 3 days at a temperature of 20°C. Indicates strength, hot strength, water deterioration resistance, moisture deterioration resistance, and failure state.

*The alpha vents in the state of destruction in the table are as follows.

A: FRP material destruction.

B: Failure in which FRP material failure and adhesive cohesive failure coexist.

C: Cohesive failure of adhesive.

D: Destruction at the interface between FRP and primer.

[Storage stability test]

Contains 1 kg of the primer composition solution obtained in the above Examples and Comparative Examples! Fill it into a t11 tin can,
After replacing the inside with nitrogen gas, the container was tightly stoppered.

This can was stored in a constant temperature bath at a temperature of 40°C for 30 days, after which the can was opened and the primer composition was removed. Changes in the appearance of the 8 liquids were observed. The results are shown in Table 5.

[Colorability test by outdoor exposure]

251111X 100+l@X 3s+s white FR
The primer composition solutions obtained in the above Examples and Comparative Examples were thinly applied with a brush to one side of the P plate. this,
The specimen was set facing south at an angle of 45° to the horizontal with the side on which the primer composition was applied facing upward, and after being left outdoors for 30 days, the change in hue of the primer composition was observed. The results are shown in Table 5.

Table 5 [Effects of the Invention] As can be understood from the above results, the primer composition of the present invention is suitable as a primer for polyurethane adhesives or sealants, and exhibits the excellent effects shown below. have

1) When used as a primer for polyurethane adhesives or sealants, extremely excellent adhesive properties can be obtained even under various environmental conditions. For example, when using conventional primer compositions, heat resistance and water resistance However, according to the primer composition of the present invention, material destruction of the adherend,
Alternatively, the adhesive force is increased to the extent of cohesive failure of the adhesive or sealant, the strength is significantly improved, and excellent adhesive or sealing properties are obtained.

2) Even when used as a primer when applying a soft polyurethane adhesive or sealant with a Young's modulus of 200 kg/cm or less after curing, it will not cause interfacial failure and will not cause material failure or adhesion of the adherend. Adhesion is improved to the extent of cohesive failure of the agent or sealant.

3) Even when the primer-applied portion is exposed to the outer surface of the adherend and exposed outdoors, the primer composition does not become colored and does not cause poor appearance.

4) Has practically sufficient storage stability.

Claims (1)

[Claims] 1) A polyol compound (A
), a polyisocyanate compound (B) having two or more isocyanate groups directly bonded to an aliphatic group, and a catalyst (C). 2) The primer composition according to claim 1, wherein the polyisocyanate compound (B) having two or more isocyanate groups directly bonded to an aliphatic group is a polyisocyanate compound having 15% by weight or more of isocyanate groups. thing. 3) The ratio of active isocyanate groups in the polyisocyanate compound (B) having two or more isocyanate groups directly bonded to an aliphatic group is the proportion of active isocyanate groups in the polyol compound (A) having an average number of hydroxyl groups of 4 or more and directly bonded to the aliphatic group. The primer composition according to claim 1 or 2, wherein the amount of the primer composition is 10% by weight or more based on the total weight of the polyisocyanate compound (B) having two or more isocyanate groups.