JPS6372774A - Primer - Google Patents

Abstract

PURPOSE:To provide a primer suitable for use in bonding specified resin materials with excellent bond strength by using an alpha-cyanoacrylate, consisting of octadecyldimethyl[3-(trimethoxysilyl)propyl]ammonium chloride. CONSTITUTION:Octadecyldimethyl[3-(trimethoxysilyl)propyl]ammonium chloride (A) is used as a primer. The component A is dissolved in an org. solvent (B) having a surface tension lower than the critical surface tension of a resin (C) to which the primer is applied (e.g., ethanol for PE, ethyl acetate for polyacetal) in such an amount as to give a concn. of 0.001-10wt%. The resulting solution is applied to the surface of a non-polar or highly crystalline resin (C) such as PE, polyacetal, etc. in a coating weight of 0.001-1g/m<2>. The resin is then air-dried to remove the solvent, thus obtaining an adherend. The treated surfaces of the adherends are firmly bonded to each other by using an alpha-cyanoacrylate (D).

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a primer (undercoat) used when adhering non-polar or highly crystallized resins, or painting or printing such resins using α-cyanoacrylate. be.

The purpose of the present invention is to use α-cyanoacrylate to successfully adhere materials such as non-polar or highly crystallized resins, which have traditionally been difficult to adhere, paint, or print, or to apply coatings to such materials. Another object of the present invention is to provide a primer that can be used to perform printing etc. satisfactorily.

Non-polar or highly crystallized resins, such as polyolefins such as polyethylene, polypropylene, polybutene, and polyfluoroethylene, polyethylene terephthalate, polyacetal, and nylon, as well as soft PvC films containing large amounts of plasticizers, etc. It is a material that is difficult to glue, paint, and print.
By ordinary methods, it is not possible to adhere these resins well or to apply coating or printing to the surfaces of these resins.

Conventionally, in order to improve the adhesive properties of these materials, for example, polyethylene and polypropylene are subjected to oxidation treatments such as flame treatment, corona discharge treatment, radiation treatment, and dichromate or sulfate treatment to remove polarity such as carbonyl groups. Surface treatment methods have been proposed to generate groups on the surfaces of these materials.

In addition, special chemical treatments such as lithium paper treatment, alkali heat treatment in a helium stream, and ammonia solution treatment of metallic sodium have been proposed for resins such as polyfluoroethylene that cannot be surface oxidized. .

However, these treatment methods require special equipment and are complicated to work with, and have drawbacks such as not being able to uniformly treat objects with complex shapes, and being expensive. There is.

Various proposals have also been made regarding primers.
JP-A-52-98062, JP-A-56-141328 and JP-A-57-119929 propose primers in which chlorinated polyethylene, chlorinated polypropylene, or fatty acid-modified acrylated alkyd resin is dissolved in an organic solvent.

However, according to JP-A No. 58-8754, these primers may have good adhesion to polyolefin but poor adhesion to topcoat, or may show good adhesion between topcoat and polyolefin. Even so, it has been pointed out that there is a drawback that inter-film adhesion deteriorates due to repeated cooling and heating cycles.

Also, JP-A No. 54-124048, No. 124049, No. 1
According to 24095, solid rubber on a polyolefin base material,
They have proposed a 9-functional polyolefin by blending unsaturated carboxylic acid or its derivative and a radical generator, but according to JP-A-57-38827, these methods produce unreacted unsaturated carboxylic acid, radical generator, etc. It is said that these substances remain and have an undesirable effect on the adhesion of the paint film.

Furthermore, JP-A-54-124050, JP-A-55-34270,
According to 55-84271, propylene/styrene/
An improved resin containing a butadiene block copolymer and an inorganic filler as essential components has been proposed, but even with this method, drawbacks such as poor weather resistance in non-coated areas and low temperature brittleness due to the filler formulation have been pointed out. It seems that there are various problems such as If non-polar or highly crystallized resins such as polyolefins are properly adhered or painted or printed on the surface of these resins, it is possible to utilize the excellent physical properties of polyolefins, reduce weight as a substitute for metal materials, and provide non-rusting properties. It has many advantages such as cost reduction and cost reduction, and it is thought that its contribution to various fields such as the automobile industry and the electrical equipment industry will be significant.

In view of these circumstances, the present inventors have made extensive research efforts to develop a surface treatment method that is simple and speedy compared to these conventional techniques. They developed a primer that made printing possible, and thus completed the present invention.

That is, the present invention relates to a primer comprising octadecyldimethyl(3-()rimethoxysilyl)propyl]ammonium chloride for applying α-cyanoacrylate to nonpolar or highly crystallized resins.

In the present invention, α-cyanoacrylate is converted into a non-polar or highly crystallized resin! l! Applying to I means adhering those resins using α-cyanoacrylate, or using α-cyanoacrylate (mainly a hardened film).
This refers to the use of these resins as an undercoat for paint or printing ink in painting or printing.

The primer of the present invention is octadecyldimethyl (3-(
It consists of ammonium chloride (hereinafter referred to as a silane compound), and AY43-021 (trade name manufactured by Toray Silicone) is a commercially available product.

The primer of the present invention is used by applying α-cyanoacrylate when adhering non-polar or highly crystallized resin, or when painting or printing the resin. Since it is desirable to control the coating thickness during use in order to fully exhibit the effects of the present invention, it is desirable to use it as a solution.

The organic solvent used for making the solution is a general organic solvent that can completely dissolve or disperse the above-mentioned organometallic compound, has appropriate volatility, and is industrially easily accessible. It is desirable that it be available.

In addition, the solvent is preferably one that can sufficiently wet the surface of the resin such as polyolefin in order to make the primer work more efficiently, and for this purpose, the surface tension of the organic solvent must be equal to the critical surface tension γ Choosing a smaller one is even more desirable. The following table shows typical values of surface tension and critical surface tension that can be used as a reference when selecting the solvent to be used.

The concentration of the silane compound when made into a solution is 0.001 to 1
Preferably it is 0% by weight. As will be described later, the silane compound applied to the surface of the base material can best exhibit the desired effect of the present invention when it is applied to a thickness close to that of a monolayer, and the concentration is O. , 001% makes it easy to achieve the objective, and as the concentration increases, the film of the silane compound becomes thicker in proportion to it, and if it becomes too thick, the layer becomes a brittle layer.

The α-cyanoacrylate in the present invention is represented by the following general formula.

In the above formula, R includes alkyl, alkenyl, cyclohexyl, aryl, and alkoxyalkyl groups, specifically methyl, ethyl, n-propyl, n
-butyl, isobutyl, n-pentyl, allyl, cyclohexyl, benzyl, methoxyglobyl groups, and the like.

These α-cyanoacrylates are the main components of commercially available cyanoacrylate-based instant adhesives, and in the present invention, these commercially available adhesives are directly used as α-cyanoacrylates. You can also use

Commercially available cyanoacrylate adhesives use α-cyanoacrylate as a paste, and are made into adhesives by blending various components as shown below, for example, as desired.

(1) Stabilizers (2) Thickeners (3) Modifiers (4) Stabilizers such as colorants are used to improve the storage stability of cyanoacrylate adhesives, and are usually used as anionic polymerization inhibitors. Sulfur dioxide, aromatic sulfonic acids, sultones, etc. are also used as radical polymerization inhibitors [hydroquinone,
Hydroquinone monomethyl ether is used.

Since α-cyanoacrylate, which is the paste, is originally a low-viscosity liquid of about several cps, thickeners are used to thicken it into a viscous liquid of several tens to several thousand cps, depending on the application. For example, polymethyl methacrylate, acrylic rubber, and cellulose derivatives are dissolved and used.

Modifiers are blended to improve impact resistance, heat resistance, etc., which are disadvantages of cyanoacrylate adhesives.For example, to improve heat resistance,
Maleic anhydride and its derivatives shown in Japanese Patent No. 2757 are used.

In addition, in order to make it possible to bond porous wood materials containing acidic sap, which have traditionally been considered difficult to bond, a crown compound as disclosed in Japanese Patent Publication No. 55-2258 has been used. be.

Furthermore, in order to impart flexibility to the adhesive layer after hardening, a plasticizer such as tricresyl phosphate, dioctyl phthalate or dimethyl sepacate may be added.

Coloring agents are used to color adhesives in order to make it easier to identify adhesive locations.
In some cases, acid salts of basic dyes shown in the above publication are blended.

In addition, for the purpose of imparting fragrance to adhesives, for example, JP-A-53
In some cases, an ester derivative fragrance shown in Japanese Patent No. 58541 is added.

Further, in the present invention, α-cyanoacrylate diluted with a specific organic solvent can also be used. Suitable organic solvents include toluene, butyl acetate, or methyl chloroform, which are compatible with α-cyanoacrylate and do not impair stability, and these solvents do not contain water or other impurities. is preferred.

When using the primer of the present invention for adhering non-polar or highly crystallized resins, the application method is as follows: When adhering a combination of non-polar or highly crystallized resin materials as adherends, both of them may be used. When the surface is also non-polar or a combination of a highly crystallized resin and a polar material, it is possible to immerse only the former surface in a primer solution for a few seconds, apply it with a brush, spray it, etc., and apply the primer in this way. By air-drying the adherend and removing the solvent, α
- The adherend can be made to adhere well with cyanoacrylate.

The adherend made of a non-polar or highly crystallized resin coated with the primer of the present invention in this manner is adhered by conventional means using α-cyanoacrylate, and the obtained adhered body has an extremely high quality. It has adhesive strength.

Other methods include applying a mixture of α-cyanoacrylate and a silane compound, if necessary a solution diluted with an organic solvent, to the surface of the adherend, or using a two-liquid discharge type coating machine [α - It is also possible to adopt a method of simultaneously discharging a solution of cyanoacrylate and a silane compound to apply and bond the primer and adhesive at the same time. However, when the mixing method is employed, sufficient care must be taken when handling to avoid contamination with foreign substances such as moisture, amines, and alcohols, as α-cyanoacrylate has the unique property of exhibiting strong anionic activity.

The method of converting or printing to a non-polar or highly crystallized resin is to apply a primer using the above method on the base material surface made of those resins, apply α-cyanoacrylate on top of the primer, and then apply a film of the polymer. By forming this, the base material becomes a base material with good suitability for painting and printing, so it can be coated on that surface by conventional means, and the base material painted or printed in this way has excellent performance. ie non-polar or highly crystallized resins.

The method of applying the primer of the present invention when painting or printing is almost the same as when applying adhesive, but the excellent effects in painting or printing are produced by taking the following steps, so the method will be described below. The process described is a preferred method of painting or printing.

First, as a first step, a primer made by dissolving a silane compound in an organic solvent is applied to the surface of the substrate to be painted or printed.

The above primer can be applied to the surface of the substrate by the usual brushing, dipping, or spraying methods, and the open time after treatment is usually 5 to 50 minutes at room temperature.
It usually takes 60 minutes, but it can take several days depending on the work process.

As a second step, α-cyanoacrylate is applied onto the substrate coated with the primer to form a film of α-cyanoacrylate polymer.

The α-cyanoacrylate can be applied by a brushing method using a brush treated with an acid in advance, a dipping method, a spraying method, or the like.

However, when using the spray method, it is preferable to use a diluted solution of α-cyanoacrylate in an organic solvent to prevent problems with nozzle clogging.

Furthermore, when using a commercially available cyanoacrylate adhesive as α-cyanoacrylate, it is preferable to use one that is commercially available as a low viscosity grade.

The substrate coated with α-cyanoacrylate is 12
Leave to stand for a period of time to form a thin layer of α-cyanoacrylate polymer on its surface.

Although the film thickness of the α-cyanoacrylate polymer is not particularly limited, it is preferably about 10 to 50 μm so as to avoid glue gaps.

By the method described above, the base material coated with the primer and α-cyanoacrylate is coated with a general paint or printed with a printing ink.

There are various types of paints and printing inks, and there are various classification methods, but the following can be cited for vehicle resin bottom classification.

Rosin conductor, nitrocellulose resin, vinyl resin, acrylic resin, polyester resin, polyamide resin, polyurethane resin, phenolic resin, epoxy resin, aminoalkyd resin, melamine resin,
UV-curable acrylic oligomers and the like can be used in the present invention, but depending on the intended use, polyurethane resins, epoxy resins, alkyd resins, etc. are more suitable for use in polyolefins. Particularly preferred are paints or printing inks.

Furthermore, since the heat resistance of the base resin, particularly polyolefin, of the baking paint is limited, it is preferable that the baking temperature is 90° C. or lower.

The coating method can be done by conventional methods such as brushing, bar coater, roller or spraying, while the printing method can be done by conventional methods such as silk screen printing, gravure printing or flexographic printing. This can be done using the following method.

The primer of the present invention is a non-polar or highly crystallized resin.
The reason for improving adhesion using cyanoacrylate or the ability to paint or print on the resin using α-cyanoacrylate and paint or printing ink is unknown, but when applied very thinly. , that is, 0.001 to 1? The effect is most noticeable when /d is applied.

It is estimated that the primer of the present invention is most effective when applied in a state close to a monomolecular layer, and since it has the structure of a silane compound, that is, a polar segment and a non-polar segment, the effect of the present invention is It is presumed that this is expressed by the following mechanism.

That is, the silane compound of the present invention exists in a state close to a monomolecular film between the surface of the non-polar or highly crystallized resin and the α-cyanoacrylate layer (7-layer or hardened polymer film layer), and The group that has high affinity with the α-cyanoacrylate layer has a high affinity with the α-cyanoacrylate layer, in other words, the lipophilic group and the polar group are arranged in an orderly manner, and act as a binder between the resin layer and the α-cyanoacrylate layer. It is estimated that the effect will be expressed.

Therefore, in order to better exhibit the effects of the present invention, the concentration of the silane compound, the amount of application, etc. must be determined by considering the material of the adherend or base material. It goes without saying that good results will not be obtained if there is too little and one layer of primer cannot completely cover the surface to be bonded, painted, or printed, and if there is too much, one layer of primer becomes a monomolecular layer. When the thickness far exceeds α, the layer itself becomes a fragile layer and the effect of the present invention is no longer expressed.
001~1? /d more preferably α01~0y1f/r
It is preferable for the present invention to apply the coating so that it becomes rl.

By strongly bonding the non-polar or highly crystallized resin and α-cyanoacrylate through the silane compound, the adhesion of the resin is strengthened by α-cyanoacrylate, and the film of α-cyanoacrylate polymer is formed. After firmly adhering to the surface of the resin, it can be easily painted or printed using commonly used paints or printing inks without causing any problems.

The excellent effects obtained by the present invention were first achieved by a combination of α-cyanoacrylate, a silane compound, and a non-polar or highly crystallized resin. Titanium compounds have been considered as primers or surface treatments, but in those cases, epoxy, urethane, rubber, or acrylic adhesives were used, so they were not very effective. Therefore, the effects of the present invention cannot be predicted from these results, and the effects produced by the present invention are so excellent that those skilled in the art cannot predict them.

Furthermore, as a matter of course, the intended effects of the present invention are as follows:
It is expressed only when the base material is a non-polar or highly crystallized resin, and other base materials such as metal, wood,
This does not occur in ceramics, etc.

The primer of the present invention is effective for non-polar or highly crystallized resins such as polyethylene terephthalate, polyacetal, nylon, etc., but is particularly effective for polyolefins. Next, the present invention will be explained in more detail with reference to Examples and Comparative Examples.

Example 1. Comparative Example 1 The following primers, adherends, and α-cyanoacrylates were used.

t Primer octadecyldimethyl (3-()rimethoxysilyl)propylammonium chloride (commercial product: Ay43-0
21, )-Resilicon ■→The above compound 0.3y- was dissolved in methyl chloroform industrial grade (manufactured by Toagosei Kagaku Kogyo ■) 99.754 to prepare a primer solution.

2 Adherent material (1) Polypropylene plate (25x100x
2 dragons) (2) Polyethylene plate (25X1
00X2mm)+31EPT plate (25X
100 x 3 m) & α-Cyanoacrylate Aron Alpha + 201 (Cyanoacrylate adhesive; Part name manufactured by Toagosei Chemical Industry Co., Ltd.) Apply the above primer solution on both sides of the test piece with a brush, let it air dry for about 5 minutes, and then apply α-cyanoacrylate on one side. - Cyanoacrylate was applied, both sides were brought together, and a pressing load of a, 1 and 9f/d was applied and cured for 24 hours.

The tensile shear adhesive strength was measured at a tensile speed of 20 using a Strograph W type tester in accordance with JISK 6861-1977.
Measured with fi/Otori.

As a comparative example, the adhesive strength was measured in the same manner as in Example 1 except that the adhesive was bonded without using a primer.

These results are shown in Table 1.

Table 1 Material fracture: Base material fracture tensile shear adhesive strength is the average value of three test pieces.

Claims (1)

[Claims] 1. A primer consisting of octadecyldimethyl[3-(trimethoxysilyl)propyl]ammonium chloride for applying α-cyanoacrylate to non-polar or highly crystallized resins.