JPH1081867A - Primer composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an isocyanate primer compsn. which is effective in adhering a hardly adherable coated steel sheet by compounding a silicone-modified acrylic resin with an isocyanate compd. SOLUTION: This compsn. is prepd. by adding 2-40 pts.wt. isocyanate compd. to 1 pt.wt. silicone-modified acrylic resin. The resin has silicone bonds introduced into the acryic main chain and pref. is one obtd. by modifying the main chain with an alkoxysilane Si(OR)n . Pref. the isocyanate compd. is not a single isocyanate compd. but a combination of several isocyanate compds., esp. pref. a combination of arom. and aliph. isocyanate compds.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an isocyanate primer composition capable of exhibiting sufficient adhesiveness in a short period of time even on a coated steel sheet having poor adhesion.

[0002]

2. Description of the Related Art Conventionally, when a urethane-based sealing material is used for bonding between a coated steel sheet for automobiles and glass, a primer using a polyester resin and an isocyanate compound has been used.

[0003] In recent years, however, the influence of acid rain on coated steel sheets has become a problem, and the use of hard-to-adhesion coated steel sheets coated with a fluorine-based paint or melamine-free paint has increased as a measure against acid rain. Have been doing. It is difficult to obtain a sufficient adhesiveness developing speed with the above-mentioned primer for such a hardly adhered coated steel sheet. For this reason, if the impact is applied to the automobile within a short time after bonding the automotive coated steel sheet and the glass, the glass may be detached due to poor adhesion.

[0004]

The conventional polyester resin / isocyanate compound-based primer has sufficient adhesiveness, that is, an isocyanate primer which is effective for bonding hard-to-adhesion coated steel sheets which cannot exhibit sufficient adhesion in a short time. A composition is provided.

[0005]

Means for Solving the Problems The present inventors have found that by blending an isocyanate compound with 1 part by weight of a silicone-modified acrylic resin, it is possible to improve the adhesiveness of the primer and complete the present invention. I let it. That is, an object of the present invention is to provide an isocyanate primer composition characterized in that 2 to 40 parts by weight of an isocyanate compound is added to 1 part by weight of a silicone-modified acrylic resin.

Hereinafter, the present invention will be described in detail. In the present invention, an acrylic resin modified with silicone is used. This is a silicone-modified acrylic resin in which a silicone bond has been introduced into the main chain of the acrylic resin, and it is preferable that the acrylic main chain be modified with alkoxysilane Si (OR) _n. Although there are various grades of the alkoxysilane-modified acrylic resin due to the difference in the skeleton caused by the difference in the monomer, Zemrak YC-3623 (manufactured by Kaneka Chemical Co., Ltd.) is preferred.

[0007] By blending the silicone-modified acrylic resin into the primer, the silicone-modified acrylic resin functions as a film-forming component, and can exhibit good adhesiveness even to a poorly adherent coated steel sheet. In addition, the silicone-modified acrylic resin not only exhibits good adhesiveness to hard-to-adhesion coated steel sheets, but the main chain of the silicone-modified acrylic resin has polarity,
Since the introduced silicone bond is non-polar, it can have adhesiveness to a wide range of polar substances.

The isocyanate compound used in the present invention is not particularly limited, and 4,4'-diphenylmethane diisocyanate (MDI), tolylene diisocyanate (TD
I), xylene diisocyanate (XDI), hexamethylene diisocyanate (HMDI), hydrogenated (hydrogenated) MDI, hydrogenated TDI, hydrogenated XDI, isophorone diisocyanate (IPDI), aromatic aliphatic polyisocyanate, aromatic polyisocyanate, Various examples of triphenylmethane triisocyanate, tris-p-isocyanate phenyl thiophosphate, and the like, which are appropriately combined and mixed, may be used. It is more preferable to use aromatic and aliphatic isocyanate compounds in combination. For example, 4,4 '
Preferred examples include a combination of diphenylmethane diisocyanate (MDI), tolylene diisocyanate (TDI), xylene diisocyanate (XDI), hexamethylene diisocyanate (HMDI), and aromatic isocyanate. By using a plurality of isocyanate compounds and utilizing the difference in curing speed between them, a primer composition corresponding to a wide range of adherends and adhesives can be obtained.

[0009] Death module RF having three functions
E (manufactured by Bayer AG) and tolylene diisocyanate (T
DI) and hexamethylene diisocyanate (HMDI)
Death module HL (manufactured by Bayer AG), which is an adduct product of the above, has a similar effect and is preferably used.

The compounding amount of the isocyanate compound is 2 to 40 parts by weight based on 1 part by weight of the silicone-modified acrylic resin,
Preferably it is 5 to 30 parts by weight. If less than 2 parts by weight,
The adhesion between the primer layer and the adhesive is not sufficient, and if it exceeds 40 parts by weight, the adhesion between the primer layer and the adherend becomes insufficient.

Further, it is preferable that carbon black is added to the primer composition of the present invention in order to impart weather resistance.

The isocyanate primer composition of the present invention is obtained by dissolving and diffusing a silicone-modified acrylic resin, an isocyanate compound and various additives as necessary in various solvents. As the solvent that can be used, any of various known solvents can be used as long as they are inert to the isocyanate group.Specifically, ethyl acetate, ester solvents such as butyl acetate, Examples thereof include ketone solvents such as methyl ethyl ketone (MEK) and acetone, and aromatic solvents such as toluene. Preferably, an ester solvent such as ethyl acetate or methyl ethyl ketone (ME
Ketone solvents such as K) are preferable from the viewpoint of affecting the human body. Particularly preferred are ester solvents such as ethyl acetate.

The total solids content in the primer is 2 to 30% by weight, preferably 5 to 20% by weight. It is preferable to add a solvent so that the total solid content in the primer falls within this range, from the viewpoint of viscosity (ease of application) and adhesiveness.

As a method for producing such an isocyanate primer composition of the present invention, any of various known methods capable of sufficiently mixing the respective components can be applied. For example, mixing by a ball mill is exemplified. .

The isocyanate primer composition of the present invention can be suitably used when a coated steel sheet coated with a fluorine-based coating, a melamine-free coating or the like is used as an adherend. In particular, a primer containing a conventional polyester resin and an isocyanate compound can be favorably used for a poorly-adhesive coated steel sheet which cannot exhibit sufficient adhesiveness.

A preferable example of the sealing material using the isocyanate primer composition of the present invention is a urethane-based sealing material. The present invention can provide good adhesion to any urethane-based sealing material. As such a urethane-based sealing material, W is used.
S-100 (manufactured by Yokohama Rubber Co., Ltd.) is preferably exemplified,
It is not limited to these.

The isocyanate primer composition of the present invention and a urethane-based sealing material are used to adhere to a poorly adherent coated steel sheet. Examples of the adherend include glass and polyvinyl chloride.

The isocyanate primer composition of the present invention can be easily cured by leaving it at room temperature. Further, the isocyanate primer composition of the present invention can provide sufficient adhesion in a short time even at a low temperature, that is, under a condition where the moisture in the air is small.

The method of use of the present invention may be the same as that of a normal isocyanate-based primer composition. The primer composition of the present invention is applied to a portion to be adhered by spraying or the like, left for a suitable time and dried. What is necessary is just to adhere | attach the adhesion | attachment part with a normal method.

In particular, the primer composition of the present invention can be used when attaching glass to a vehicle body made of a hard-to-adhesion coated steel sheet coated with a fluorine-based paint or a melamine-free paint. More specifically, it can be suitably used as a primer when the adherend is a painted steel plate for a vehicle and the adhesive is a urethane-based adhesive.

By using the primer composition of the present invention, a conventional polyester resin / isocyanate compound-based primer can be suitably used for a poorly-adhesive coated steel sheet in which it is difficult to exhibit sufficient adhesiveness. Good expression. In particular, the adhesiveness to fluorine-based paints and melamine-free paints is high.

[0022]

The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the invention thereto. Various primer compositions were prepared according to the formulations shown in Table 1, and their adhesiveness and adhesiveness were evaluated.
Evaluation of adhesion development, after coating the primer, scratch the primer in a grid pattern, peel off with a cellophane tape,
The time (minutes) at which the primer layer did not adhere to the tape was evaluated. The test was performed under the conditions of 20 ° C. and 65% relative humidity. The adhesion was evaluated by applying a primer to the adherend, drying the primer (elapsed 5 minutes after application), applying an adhesive, curing the adhesive, and performing a hand peel test.
At this time, a coated steel plate was used as the adherend.

[0023]

The description in the table is as follows. Carbon black: A2899 (manufactured by Asahi Carbon Co., Ltd.) Resin 1: ZEMRAC YC-3623 (alkoxysilane-modified acrylic resin manufactured by Kanegabuchi Chemical Co., Ltd.) Resin 2: Pandex T-5205 (polyester polyurethane manufactured by Dainippon Ink and Chemicals, Inc.) Isocyanate compound: Desmodur RFE (manufactured by Bayer) / Desmodur HL (manufactured by Bayer) = 2 /
Admixture 1: Standard coated steel sheet Adherend 2: Acid rain resistant coated steel sheet Adhesive: WS-100 (Yokohama Rubber Co., Ltd.)

CF: Aggregates of the adhesive layer were broken. AF: The interface between the primer and the adherend was destroyed. PS: The interface between the primer and the adhesive was broken.

As shown in the table, the primer composition of the present invention not only has good adhesiveness to acid-rain coated steel sheets, but also has good adhesiveness to ordinary coated steel sheets. Was. It was also found that the adhesiveness after curing was good.

[0027]

According to the primer composition of the present invention, the conventional polyester resin / isocyanate compound-based primer has good adhesiveness to a poorly-adhesive coated steel sheet which did not exhibit sufficient adhesiveness.

Claims (1)

[Claims] 1. An isocyanate primer composition comprising 2 to 40 parts by weight of an isocyanate compound per 1 part by weight of a silicone-modified acrylic resin.