JPH08199119A - Primer and bonding method using the primer - Google Patents

Abstract

(57) [Abstract] [Purpose] An object of the present invention is to provide a primer which has an excellent effect of imparting excellent adhesiveness to an adherend having difficulty in adhesion and which is easily used with good workability, and an adhesion method using the primer. . A primer comprising atactic polypropylene or a metal salt of polyethylene wax containing one or more acid groups and an organic solvent, and the surface of an adherend treated with the above primer After that, the bonding method is characterized by bonding with an adhesive.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adhesive primer, and more particularly to an adhesive primer suitable for nonpolar or highly crystalline adherends having poor adhesion.

[0002]

2. Description of the Related Art Synthetic resins such as polyolefin resins, cross-linked polyolefin resins and polyacetal resins are widely used as films, sheets, pipes and various molded products. These synthetic resins are the same or different from these synthetic resins. Applications for bonding materials are also expanding.

However, the above-mentioned synthetic resins such as polyolefin resins, cross-linked polyolefin resins and polyacetal resins are non-polar or highly crystalline and therefore difficult to bond, and are generally regarded as difficult-to-adhere adherends. There is.

Various attempts have been made in the past to satisfactorily bond the above-mentioned difficult-to-adhere adherends. For example, a method of corona-radiating the surface of the adherend prior to the adhesion [Modern Plastics, 38 , 9 (1961) ) P199], a method of flame treatment [British plastic, 37 , (196
4) p142], a method of irradiating with ultraviolet rays [Chemical technology, 3 ,
(1982) p166], a method of oxidation treatment with a mixed solution of 2-chromate and sulfuric acid [Polymer, 22 , 7 (198).
1)] etc. have been proposed.

However, all of the methods proposed above require special devices and instruments, have poor workability, and have problems in terms of safety, and are not preferred methods in practice.

Further, the polyolefin resin and the cross-linked polyolefin resin can be adhered by the heat fusion method, but in the case of the heat fusion method, it is difficult to adhere them to different materials, and some products can be heated. In some cases, it is not available and there is a problem in that it is restricted in terms of use.

Further, various methods using a primer have been investigated. For example, in JP-A-63-56584, the surface of a difficult-to-adhere adherend is treated with aminosilane, and then an α-cyanoacrylate adhesive is used. A method for adhering an adherend having difficulty in adhesion has been proposed, which is characterized in that the adherends are used.

However, in the case of the method proposed above, when aminosilane is excessively left on the surface of the adherend, the adhesive strength is lowered, and it is difficult to control the coating amount of aminosilane and the workability is poor.

[0009]

DISCLOSURE OF THE INVENTION In order to solve the above-mentioned conventional problems, the present invention provides a primer which has an excellent effect of imparting excellent adhesiveness to an adherend having difficulty in adhesion and is easily used with good workability. It is an object to provide an adhesion method using a primer.

[0010]

The primer according to the invention of claim 1 (hereinafter referred to as "first invention") is characterized by comprising atactic polypropylene and an organic solvent, whereby the above object is achieved. To be achieved.

The primer according to the second aspect of the invention (hereinafter referred to as the "second invention") comprises a metal salt of polyethylene wax containing one or more acid groups and an organic solvent. The above object is achieved thereby.

Further, in the bonding method according to the invention of claim 3 (hereinafter referred to as "third invention"), the surface of the adherend is treated with the primer of claim 1 or 2, and then the adhesive is applied. It is characterized by using and adhering.

The atactic polypropylene used for the primer according to the first invention has a weight average molecular weight of 50, which has an irregular three-dimensional structure in which methyl groups are randomly distributed.
It is a non-crystalline polypropylene having a relatively low molecular weight of about 00 to 20000, and examples thereof include "Vistak" series manufactured by Chiba Fine Chemical Co., Ltd.

The type of organic solvent used in the primer according to the first invention is not particularly limited as long as it can dissolve the atactic polypropylene, and specifically, ethanol, n-butanol, iso. −
Alcohols such as propanol, aromatic hydrocarbons such as toluene and xylene, alicyclic hydrocarbons such as cyclohexane, aliphatic hydrocarbons such as hexane and heptane, ketones such as acetone and methyl ethyl ketone, ethyl acetate,
Acetates such as butyl acetate, chlorinated solvents such as 1,1,1-trichloroethane and 1,1,2-trichloro-1,2,2-trifluoroethane, tetrahydrofuran,
Dimethyl sulfoxide and the like can be mentioned, and one or more of these are preferably used, and among them, toluene, cyclohexane and the like are more preferably used.

The content of the atactic polypropylene in the primer according to the first invention is not particularly limited, but is preferably 0.1 to 20% by weight, more preferably 1 to 15% by weight. .

If the content of atactic polypropylene in the above primer is less than 0.1% by weight, a sufficient adhesiveness-imparting effect cannot be obtained, and if it exceeds 20% by weight, it is applied to the surface of an adherend. The dried primer layer becomes too thick and becomes a brittle layer, and the adhesive force is rather reduced.

Next, the metal salt of polyethylene wax containing one or more acid groups used in the primer according to the second invention means one or more compounds having an acid group such as carboxylic acid. Is a metal salt obtained by reacting a part or all of the acid groups of a relatively low-molecular-weight polyethylene wax containing an acid group with one or more polyvalent metals or compounds of polyvalent metals. .

The types of compounds having the above acid group include
Although not particularly limited, α- or β-alkyl derivatives of (meth) acrylic acid such as (meth) acrylic acid, α-ethylacrylic acid and crotonic acid, fumaric acid, maleic acid, citraconic acid, itaconic acid Carboxylic acid-containing compounds such as unsaturated dicarboxylic acid monoester derivatives such as succinic acid mono (meth) acryloyloxyethyl ester, phthalic acid mono (meth) acryloyloxyethyl ester, etc., styrene sulfonic acid, vinyl sulfone Sulfonic acids such as acids, sulfonic acid-containing compounds such as sulfonic acid-containing acrylamides such as 2- (meth) acrylamide-2-methylpropanesulfonic acid, sulfinic acid-containing compounds, phosphonic acid-containing compounds, boric acid-containing compounds, and the like, One or more of these are preferably used, From the strength of the acid, carboxylic acid-containing compounds such as (meth) acrylic acid and succinic acid mono (meth) acryloyloxyethyl ester, and sulfonic acid-containing compounds such as 2-acrylamido-2-methylpropanesulfonic acid are more preferable. Used.

The polyethylene wax into which the compound having an acid group is introduced has a weight average molecular weight of 1000 to 200.
A relatively low molecular weight of 0 is preferred.

The type of polyvalent metal or compound thereof capable of forming a salt with the above-mentioned polyethylene wax containing an acid group is not particularly limited, but copper, mercury, beryllium, magnesium, calcium, strontium are included. , Vanadium, zinc, cadmium, aluminum, titanium, germanium, tin, bismuth, chromium, molybdenum, manganese, iron, nickel, cobalt,
Zirconium, polyvalent metals such as selenium, and their compounds such as fluorides, chlorides, bromides, iodides, oxides, hydroxides, sulfides, nitrides, phosphides and the like, One or more of these are preferably used, and among them, zinc group metals such as zinc, alkaline earth metals such as magnesium, and compounds thereof are more preferably used.

Further, the kind of the organic solvent used for the primer according to the second invention is not particularly limited as long as it can dissolve the metal salt of polyethylene wax containing one or more acid groups. However, specifically, one or more kinds of various organic solvents similar to the organic solvent used for the primer according to the first invention are preferably used, and among them, acetone, toluene and the like are more preferably used.

The content of the metal salt of polyethylene wax containing one or more acid groups in the primer according to the second invention is not particularly limited, but is 0.001 to 10% by weight, More preferably 0.0
It is preferably 1 to 4% by weight.

One or two of the above primers
If the content of the metal salt of polyethylene wax containing at least one kind of acid group is less than 0.001% by weight, a sufficient adhesion-imparting effect cannot be obtained, and if it exceeds 10% by weight, the adherend is adhered. The primer layer applied and dried on the surface becomes too thick and becomes a brittle layer, which rather reduces the adhesive strength.

The primer according to the first invention and the second invention may contain one or more kinds of various additives such as an amine compound, a surfactant and a colorant, if necessary, as long as the objects of the invention are not impaired. It may be contained.

The method for producing the primer according to the first invention and the second invention is not special, and for example, various conventionally known mixers equipped with a stirrer are used and a predetermined amount of the atactic polypropylene or a predetermined amount of the atactic polypropylene is used. The metal salt of polyethylene wax containing one or more kinds of acid groups, a predetermined amount of the organic solvent, and a predetermined amount of the additives and the like that are added as necessary are uniformly stirred at room temperature or under heating. A desired primer can be obtained by mixing.

In the bonding method according to the third aspect of the invention, the surface of the hardly-adhesive adherend such as a polyolefin resin, a cross-linked polyolefin resin or a polyacetal resin is treated with the primer according to the first or second aspect of the invention, and then the adhesive is used. It is performed by bonding.

The type of adhesive used in the above-mentioned bonding method is not particularly limited, but natural rubber-based adhesives,
Styrene-butadiene copolymer rubber, chloroprene rubber,
Solvent type or emulsion type synthetic rubber such as acrylonitrile-butadiene copolymer rubber, vinyl acetate resin, ethylene-vinyl acetate copolymer resin, acrylic ester resin, vinyl acetate-acrylic ester copolymer resin, etc. Adhesives, α-cyanoacrylate-based, urethane-based, epoxy-based, second-generation acrylic-based, unsaturated polyester-based reactive adhesives, ethylene-vinyl acetate copolymer resin-based, ethylene-acrylic ester copolymer resin-based Hot-melt type adhesives such as styrene-butadiene block polymer type, styrene-isoprene block polymer type, urethane type and the like are preferably used, but α-cyanoacrylate type adhesives are more preferably used.

The above α-cyanoacrylate adhesive is
It is a quick-curing instant adhesive containing an α-cyanoacrylate monomer represented by the following general formula (1) as a main component, and is particularly preferably used in the bonding method according to the third invention.

Embedded image Equation (1)

In the above formula, R is not particularly limited as long as it does not contain an anionic polymerizable group, and examples thereof include a methyl group, an ethyl group, an n-propyl group, an iso-propyl group and an n-butyl group. , Iso-butyl group, sec-butyl group, tert-butyl group, n-pentyl group, iso-pentyl group, neopentyl group, n-hexyl group, iso-
Hexyl group, n-octyl group, iso-octyl group, ethylhexyl group, alkyl groups such as dodecyl group, methoxyethyl group, ethoxyethyl group, propoxyethyl group, butoxyethyl group and other alkoxyalkyl groups, allyl group,
Propargyl group, cyclopentyl group, cyclohexyl group,
Tetrahydrofurfuryl group, benzyl group, phenyl group,
2-chloroethyl group and the like can be mentioned, and one or more of these are preferably used. Among them, a methyl group,
One or more lower alkyl groups such as an ethyl group, a propyl group and a butyl group have a high curing rate (set time) for the obtained α-cyanoacrylate monomer,
It is more preferably used.

The adhesion method according to the third aspect of the present invention will be described in detail. Although not particularly limited, for example, in the case of adhering the adherends having difficulty in adhesion, the adhesion of adherends having difficulty in adhesion After the primer according to the first invention or the second invention is applied to each surface to be dried, and when the difficult-to-adhere adherend and the dissimilar material are adhered, only the surface to be adhered of the hardly-adhesive adherend After applying and drying the primer according to the first invention or the second invention, any one of the various adhesives described above may be applied to one or both surfaces of the adherend to be adhered, and adhered by a conventional method.

[0031]

The primer according to the first aspect of the present invention, which contains atactic polypropylene as an active ingredient, exerts an excellent adhesion-imparting effect on a difficult-to-adhere adherend composed of a polyolefin resin, a crosslinked polyolefin resin, a polyacetal resin or the like. .

Further, since the primer according to the second invention contains, as an active ingredient, a metal salt of polyethylene wax containing one or more kinds of acid groups, it is difficult to be composed of a polyolefin resin, a crosslinked polyolefin resin, a polyacetal resin or the like. Adhesive It exerts an excellent effect of imparting adhesiveness to an adherend.

Furthermore, since the bonding method according to the third invention uses the primer according to the first invention or the second invention,
It is possible to easily and effectively perform the adhesion between the adherends having difficulty in adhesion or the adhesion between the adherend having difficulty in adhesion and a different material.

[0034]

EXAMPLES In order to explain the present invention in more detail, examples will be given below. In the examples, "part" means "part by weight" and "%" means "% by weight".

(Example 1)

( 1) Preparation of primer Using a Satake type stirrer (manufactured by Satake Kagaku Kikai Co., Ltd.), toluene 9
3 parts of atactic polypropylene (trade name "Vistac L", manufactured by Chiba Fine Chemical Co., Ltd.) was uniformly stirred and dissolved in 7 parts to prepare a primer having a solid content of 3%.

( 2) Evaluation Using the primer obtained above and an α-ethyl cyanoacrylate adhesive (trade name “Power Ace E”, manufactured by Sekisui Aiko), set time and tensile shear strength were as follows. It was evaluated by the method. The results are shown in Table 1.

Set time : width 25 mm, length 100
Two polypropylene plates with a thickness of 3 mm cut into mm were used as test pieces, and the primer obtained above was applied to each surface of the two polypropylene plates to be bonded and dried.
According to K-6861 “Testing method for α-cyanoacrylate adhesives”, “Power Ace E” is applied to each primer application surface, and they are attached so that the adhesion length becomes 12.5 mm. Second) was measured. A similar test was cut into a width of 25 mm and a length of 100 mm, and a thickness of 3 mm.
2 polyethylene plates were also used as test pieces.

Tensile shear strength : width 25 mm, length 100
Two polypropylene plates with a thickness of 3 mm cut into mm were used as test pieces, and the primer obtained above was applied to each surface of the two polypropylene plates to be bonded and dried.
According to K-6861, "Power Ace E" was applied to each primer-coated surface and bonded so that the bonding length was 12.5 mm to prepare a bonding test piece. After leaving the obtained adhesion test piece in an atmosphere of 20 ° C.-65% RH for 24 hours, in the same atmosphere, using a Tensilon tensile tester,
Tensile shear strength (kg / c at a tensile speed of 20 mm / min.
m ² ) was measured. The same test was performed using two polyethylene plates having a width of 25 mm and a length of 100 mm and a thickness of 3 mm as test pieces.

(Example 2)

A primer having a solid content of 7% was prepared in the same manner as in Example 1 except that the composition of the primer was 93 parts of toluene and 7 parts of "Vistac L".

(Example 3)

A primer having a solid content of 14% was prepared in the same manner as in Example 1 except that the composition of the primer was 86 parts of toluene and 14 parts of "VISTACK L".

(Example 4)

A primer having a solid content of 22% was prepared in the same manner as in Example 1 except that the composition of the primer was 78 parts of toluene and 22 parts of "Vistac L".

(Example 5)

Using a Satake type stirrer, 0.5 part of a partial zinc salt of polyethylene wax succinic acid monoacryloyloxyethyl ester was uniformly stirred and dissolved in 99.5 parts of acetone to prepare a primer having a solid content of 0.5%. It was made.

(Example 6)

A primer having a solid content of 3% was prepared in the same manner as in Example 4 except that the composition of the primer was 97 parts of acetone and 3 parts of a partial zinc salt of succinic acid monoacryloyloxyethyl ester of polyethylene wax. .

(Example 7)

A primer having a solid content of 12% was prepared in the same manner as in Example 5 except that the composition of the primer was 88 parts of acetone and 12 parts of the partial zinc salt of succinic acid monoacryloyloxyethyl ester of polyethylene wax. .

Using the six kinds of primers obtained in Examples 2 to 7 and "Power Ace E", set time and tensile shear strength were measured in the same manner as in Example 1 and the results are shown in Table 1. there were.

(Comparative Example 1)

Table 1 shows the results of measuring the set time and the tensile shear strength in the same manner as in Example 1 except that "Power Ace E" was used without using a primer.

[0055]

[Table 1]

[0056]

As described above, the primer according to the first invention and the second invention exhibits an excellent effect of imparting an adhesive property to a difficult-to-adhere adherend composed of a polyolefin resin, a crosslinked polyolefin resin, a polyacetal resin or the like. It is suitable for use as a primer for adhesion to adherends with poor adhesion.

Further, the bonding method according to the third invention is the same as the first method.
Since the primer according to the invention or the second invention is used, it is possible to easily and effectively adhere a difficult-to-adhere adherend.

Claims (3)

[Claims] 1. A primer comprising an atactic polypropylene and an organic solvent. 2. A primer comprising a metal salt of polyethylene wax containing one or more acid groups and an organic solvent. 3. An adhesion method, which comprises treating the surface of an adherend with the primer according to claim 1 or 2, and then adhering it with an adhesive.