JPS59179680A - Insulated film with adhesive layer - Google Patents

Abstract

PURPOSE:To provide the titled film excellent in anchorability between an insulated film and an adhesive layer, storability, etc., by providing two adhesive layers, upper and lower, each comprising a compsn. in which a particular crosslinker is incorporated with an acrylic copolymer on the film. CONSTITUTION:An acrylic copolymer is prepd. which comprises 40-80wt% monomer of formula I , 15-50wt% acrylonitrile, and 1-25wt% monomer of formula II. A lower adhesive layer comprising a compsn. in which 1-10pts.wt. diisocyanate of formula III and/or triisocyanate of formula IV is incorporated with 100pts.wt. said copolymer as a crosslinker is provided on an insulated film. Then, an upper adhesive layer comprising a compsn. in which 0.1-10pts.wt. monomer of formula V as a crosslinker is incorporated with 100pts.wt. said copolymer is provided on the film. Thereafter, 1-20pts.wt. alkyl-etherified melamine and 0.1-10pts.wt. polyol of formula VI, based on 100pts.wt. said copolymer respectively, are incorporated in either one of the both layers as crosslinking agent.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an insulating film having an adhesive layer, and the purpose thereof is to have good storage stability, excellent anchoring properties between the adhesive layer and the insulating fintom, and to provide good adhesion. Good adhesion to the body, as well as bending resistance, solvent resistance,
The object of the present invention is to provide the above-mentioned insulating film which is also excellent in various properties such as chemical resistance.

In recent years, with the development of the electrical equipment and electronic equipment industries, there has been an increasing demand for simpler, smaller, more reliable, and higher performance mounting methods for communication and consumer equipment. There is also a demand for insulating films used in applications that are easy to work with, have high performance, and are highly reliable.

To avoid this, there is a need for insulating films in which a high-performance adhesive layer is formed on a polyimide film or polyester film that has excellent electrical properties and good heat resistance, and the fields of its application are rapidly expanding.

In general, adhesive compositions used for adhesive layers of insulating films include acrylonitrile butadiene rubber, butyral resin, and acrylic rubber. However, insulating films made of acrylonitrile butadiene rubber or butyral resin have the drawback that the adhesive loses their activity in a short period of time unless they are stored at low temperatures, and they also have difficulty folding. Since the anchoring force between the film and the adhesive layer is weak, there is also the problem that when it is attached to an adherend, it is easily peeled off at the interface between the insulating film and the adhesive. In addition, in insulating films using acrylic rubber, the adhesive composition contains carboxyl groups consisting of acidic components such as acrylic acid, methacrylic acid, and itaconic acid in order to improve adhesiveness and react with crosslinking agents. Since it is mainly composed of a copolymer of monoethylenic monomer and acrylic acid ester, it is not chemically neutral, and if the adherend is metal, the metal will corrode after long-term use. It has the disadvantage of being

In light of these circumstances, the inventors added an acrylic diester and an organic peroxide as a crosslinking agent to a copolymer of an alkyl ester of acrylic acid or methacrylic acid, acrylonitrile, and a hydroxyalkyl ester of acrylic acid or methacrylic acid. By blending non-acidic polyfunctional compounds such as , melamine compounds, isocyanate compounds, and polyol compounds in a suitable combination, folding durability, corrosion resistance, chemical resistance, solvent resistance, anchoring strength with insulating films, It has excellent adhesive strength, and can be used, for example, when the insulating film is used as an insulating base material or cover film for a flexible printed circuit board and is bonded to metal foil such as copper foil or iron foil by pressing it with a heated roll. An adhesive composition that satisfies the above characteristics not only under high temperature and high pressure conditions of 150°C or higher and 10 kg/cA or higher, but also under low temperature and low pressure conditions of about 1 to IO kti/ca at 60 to 120°C. Various proposals are made.

In the course of continuing research related to the various proposed methods mentioned above, the inventors developed an adhesive layer of an insulating film having an adhesive layer by adding a specific amount of a specific crosslinking agent to the acrylic copolymer. When a two-layer structure is formed using two types of adhesive compositions, the anchoring properties and storage stability between the insulating film and the adhesive layer are greatly improved, and the adhesion to the metal surface of the adherend is improved. The present inventors have discovered that the various proposed methods described above can also sufficiently exhibit the various effects described above, leading to the completion of the present invention.

That is, this invention provides at least one side of the insulating film with a) 40 to 80 monomers represented by the general formula H20=Of(-COORs (wherein, R1 is an alkyl group having 2 to 8 carbon atoms)). b) 15 to 50% by weight of acrylonitrile; and C) the following general formula: (wherein R2 is a hydrogen atom or a methyl group, and R3 is an alkylene group having 2 to 3 carbon atoms). d) The following general formula as a crosslinking agent for 100 parts by weight of an acrylic copolymer consisting of 1 to 25 parts by weight of monomers; A lower layer consisting of a composition containing 1 to 10 parts by weight of a diisocyanate (which is an alkyl group having 1 to 3 carbon atoms) and/or a triisocyanate represented by the following structural formula; and the above copolymer 100. Based on the weight part, as a crosslinking agent, e) the following general formula; (wherein 8 is a hydrogen atom or a methyl group, 9 is 10 (
70H2+-n10- or -0(-OH2-OH2-
From a composition containing 01 to 10 parts by weight of a monomer represented by 0 → □ and m' = 1 to 5) and, if necessary, h) 001 to 0 parts by weight of an organic peroxide. An adhesive layer having a two-layer structure consisting of an upper layer and an upper layer is provided, and at least one of the upper and lower layers of this adhesive layer is provided with - f) as a crosslinking agent based on 100 parts by weight of the copolymer. Alkyl etherified melamine j to 20 parts by weight or g) a polyol represented by the following general formula; (wherein n is an integer from 1 to 40) The present invention relates to an insulating film having a characteristic adhesive layer.

In the insulating film of the present invention, the incyanate compound as the d component, which is blended as a crosslinking agent in the adhesive lower layer, has the function of greatly improving the anchoring property between the insulating film and the adhesive layer, but the reactivity of the -NOO group Since this is extremely strong, the reaction with functional groups such as -OH groups in the adhesive progresses over time and tends to deactivate the adhesive. Therefore, if the incyanate compound of component d is blended into the entire adhesive layer, the storage stability will be poor, and the insulating film provided with the adhesive layer must be stored at low temperatures.

However, in this invention, the adhesive layer has a two-layer structure, upper and lower layers, and the upper layer, which is substantially involved in adhesion to the adherend, does not contain an isocyanate compound, and the lower layer, which is in contact with the insulating film and is involved in the anchoring force of the adhesive, contains no isocyanate compound. Since this is blended, the upper layer will not be deactivated by isocyanate.

In addition, the acrylic diester monomer (e) component, which is blended as an essential component in the upper layer, causes a rapid radical reaction at a predetermined temperature or higher using the organic peroxide (h component) as a polymerization initiator.
It forms a copolymer with a large molecular weight in the adhesive layer, and shows almost no curing reaction until it reaches a predetermined heating temperature, so it has good storage stability and greatly improves heat resistance after curing. Further, the alkyl etherified melamine (f component) contained in at least one of the upper and lower layers and the specific polyol (g component) improve solvent resistance and heat resistance by blending them together.

Therefore, in the adhesive layer of the insulating film of the present invention, the lower layer in contact with the insulating film has a strong anchoring force with respect to the film, and the upper layer in direct contact with the adherend, which easily generates heat and becomes high temperature, has a long shelf life. It is made of a material with excellent heat resistance, and has excellent anchoring properties, heat resistance, and storage stability as a whole.Also, since the same type of acrylic copolymer is used for the upper and lower layers, there is good compatibility between the upper and lower layers, and there is no space between the layers. It has strong adhesion, and also has excellent properties such as bending durability, solvent resistance, and chemical resistance, and can be applied not only under high temperature and high pressure conditions but also at 60° when adhering to adherends such as metal foil. Adhesion can be achieved by applying a pressure of about 1 to 1.0 kg/ca for a few seconds at a low temperature of CTh 120°C.

The acrylic copolymer used in this invention contains the a-component monomer, b-component monomer, and C-component monomer in a specific ratio from the viewpoint of bending durability, corrosion resistance, stain resistance, etc. and copolymerized according to these conventional methods.

The monomer of component a above is the main component of the copolymer, and includes various acrylic alkyl esters in which the alkyl group has 2 to 8 carbon atoms, such as ethyl acrylate and n-butyl acrylate. It can be used, and there is no problem even if two or more types are used together.

If the amount of acrylonitrile used as component b is more than 500 parts by weight, the entire adhesive becomes hard and sufficient flexibility and bending durability cannot be obtained.On the other hand, if it is less than 155 parts by weight, the adhesion property decreases due to the decrease in CN- groups. becomes insufficient.

The monomer of component C has reactivity with the crosslinking agent through its functional group, that is, alcoholic hydroxyl group, and
2-Hydroxylethyl acrylate, 2-methacrylate
Hydroquine ethyl, 2-hydroxypropyl acrylate to 2-hydroxypropyl methacrylate, acrylic acid 3
-Hydroxypropyl, 3-hydroxypropyl methacrylate, etc. can be used, and two or more of these can be used.
May be used in combination with h. If the amount of the C component monomer exceeds 255 parts by weight, the crosslinking becomes too dense, resulting in a decrease in flexibility and folding durability, as well as a decrease in adhesiveness. However, if it is less than 1 weight, the content of alcoholic hydroxyl groups that participate in the crosslinking reaction will be insufficient, and a satisfactory three-dimensional structure will not be formed, resulting in a tendency to lack solvent resistance.

In this invention, the alkyl etherified melamine of component f, which is blended as an essential component in at least one of the upper and lower layers of the adhesive layer, includes ethyl etherified melamine, propyl etherified melamine, butyl etherified melamine, etc. These melamine compounds It is used in an amount of 1 to 20 parts by weight per 100 parts by weight of the copolymer. If the amount is less than 1 part by weight, the solvent resistance will be poor, and if it is more than 20 parts by weight, the folding durability will be poor.

In addition, the polyol as the component g, which may be blended in at least one of the upper and lower layers together with the component f, is effective for l-folding properties and other properties, and such a polyol is capable of ring-opening polymerization of cabrolactane monomers. When used, copolymer 1.
It is used in a proportion of 01 to 10 parts by weight based on 0 parts by weight. When the amount is less than 0.1 part by weight, the blending effect is not substantially achieved, and on the other hand, when it is more than 10 parts by weight, problems arise in heat resistance.

On the other hand, the crosslinking agent of component d, which is blended as an essential component only in the lower layer, is represented by the general formula, for example, 2, 2, 4,
4-tetramethylhexane-1,6-diisocyanate, 2,2-diethyl-4,4-dimethylhexane-1,
Either a diisocyanate such as 6-diisocyanate or a triisocyanate represented by the above structural formula is used. The amount used is 1 to 100 parts by weight of the copolymer.
If the amount is less than 1 part by weight, the anchoring force between the adhesive layer and the insulating film will be insufficient, and the adhesive layer and the insulating film will easily peel off at the interface between them when attached to an adherend, and conversely, if the amount is less than 1 part by weight, In this case, the heat resistance of the adhesive lower layer deteriorates.

With the help of peroxide, a rapid radical reaction occurs at a predetermined temperature, which greatly contributes to adhesion to adherends and side heat properties. The blending amount is 1 part acrylic copolymer
It should be 01 to 10 parts by weight to 00 parts by weight, and 0
If it is less than 1 part by weight, high-temperature adhesion will deteriorate, and if it is more than 10 parts by weight, the heat resistance will be impaired due to the presence of unreacted substances.

The h component is used as a polymerization initiator for the so-called C component, and a representative example thereof is benzoyl peroxide, but other known organic peroxides may also be used. good. The amount used is 001~0
If it is less than 0.01 part by weight, the initiation effect will be poor, and if it is more than 0.01 part by weight, it will remain and if it is rapidly heated, it will tend to form minute bubbles in the adhesive layer, resulting in poor electrical insulation. Not desirable. Note that this h component is not necessary when the adhesive layer is cured with light or electron beam.

Further, even in the case of thermal curing, it is not always necessary.

Note that the above e component and h component can be included in the lower layer as necessary, thereby enhancing their effects. Further, in the present invention, in addition to the above-mentioned crosslinking agent, various commonly used additives such as fillers, colorants, and stabilizers may be blended in both the upper and lower layers of the adhesive layer depending on the purpose. Needless to say.

In this invention, adhesive compositions for the lower layer and the upper layer are prepared by blending the above-mentioned components, and the adhesive compositions are sequentially applied onto an insulating film made of polyester film, polyimide film, etc. to form an adhesive layer. The thickness of this adhesive layer is usually 10-60 μnl for both the upper and lower layers, and 5-50 μnl for the lower layer.
It is best to keep the amount within a certain range. Especially in this case,
e in the lower layer.

Polyimide film is suitable for those using component h.

An insulating film having such an adhesive layer is, for example, an insulating base film constituting a flexible printed circuit board,
It is applied as a cover film that is attached to the copper foil or other metal foil of the board for insulation protection, an insulating film for connectors, and other insulating films used in electrical and electronic equipment, and is especially suitable as an insulating film for connectors. be.

Therefore, the adherend to which the insulating film of the present invention is applied is metal foil such as copper foil in the case of the insulating base film or cover film of the flexible printed circuit board, but it may also be a metal foil such as plate or wire. In addition to the surfaces of current-carrying materials made of metals and non-metals in the shape of , the surfaces of non-current-carrying materials that require insulation are also targeted.

Hereinafter, the present invention will be specifically explained with reference to Examples and Comparative Examples. Note that all parts refer to parts by weight.

Example 70 parts of acrylic acid n-butyl ester, 30 parts of acrylonitrile, 5 parts of acrylic acid 2-hydroxyethyl ester
100 parts of toluene and 02 parts of benzoyl peroxide were heated at 60 to 65° while stirring in a nitrogen stream.
C for 7 hours to form a viscous solution.To further increase the polymerization rate, the reaction was continued for 10 hours to achieve a polymerization rate of 90% by weight.
A copolymer solution was obtained.

To this copolymer solution, each component shown in Table 1 as a crosslinking agent is mixed with 100 parts of the copolymer in the proportions listed in the table to prepare an adhesive composition for the lower layer. An upper layer adhesive composition was prepared by blending components e and h as crosslinking agents in the proportions shown in Table 1 with respect to 100 parts of the combined composition.

Next, the lower layer is made of polyimide film (25/7772 thickness) using components e and h, and polyester film (Lumirror, manufactured by Toshisha Co., Ltd., 1 mm thick) is used without it.
The adhesive composition for the lower layer was uniformly applied on each film of 1) and allowed to dry for 60 minutes at 1loo'c to form a lower layer of adhesive with a thickness of 10 μη2, and then the adhesive composition for the upper layer 1 was adhered. A cloth was evenly spread on the surface of the adhesive lower layer and dried at 100°C for 1 minute to form an adhesive upper layer with a thickness of 20 pm, thereby obtaining an insulating film sample N [Ll~3] having two adhesive layers, upper and lower. .

Comparative Example Each component listed in Table 2 was added as a crosslinking agent to 100 parts of the copolymer to the copolymer solution in Example to obtain an adhesive composition. It was applied uniformly onto a film and dried at 100°C for 3 minutes to obtain insulating film sample papers Nos. 14 to 6 having a single layer adhesive layer with a thickness of 2Q7x772.

・) [ ・ [ Table 2 (*) f component: butyl etherified melamine (J-820 manufactured by Nippon Reichhold) g component: polyol in which n in the above general formula is 4 (Place # 305 manufactured by Daicel) d component ;Sample N[L3
is 2,2,4,4-tetramethylhexane-1,6-diisocyanate, sample N [Ll, , 2,4,5. is a triisocyanate represented by the above structural formula.

e component: ethylene glycol diester dimethacrylate (NK ester +-G manufactured by Shin Nakamura Chemical Co., Ltd.) h component: Pe/diyl peroxide Regarding the insulating film having the adhesive layer obtained in the above examples and comparative examples, After each sample was left in a constant temperature basin at 40'C for 30 days, it was attached to the treated surface of 1 ounce electrolytic copper foil under the adhesive conditions shown in Table 3, and its adhesive strength was measured.

The results are shown in Table 4 along with the adhesive strength in the normal state without the above-mentioned aging.

Note that the adhesive strength was measured according to IPc-FO-240B. For each insulating film, after adhering it to the treated surface of a BA-treated stainless steel plate, peel it off and check for adhesive residue.Those with a lot of adhesive residue (poor), those with a little adhesive residue (slightly good), and those with no adhesive at all. Anchorability was evaluated with (good) as shown in Table 4.

Table 4 As is clear from the results in Table 4 above, in the insulating film having an adhesive layer according to the present invention, since at least one of the adhesive components contains f and g, the lower layer side The upper layer, which is responsible for the strong anchoring force between the insulating film and the adhesive layer, is essentially responsible for the adhesion to the adherend, and has good storage stability and excellent high-temperature adhesion, and can be bonded for a long time under high temperature and high pressure. It can be seen that the adhesion is good not only when it is carried out over a long period of time, but also when it is carried out at a low temperature and pressure for a short period of time, and the workability is excellent.

Patent applicant: Machizuka Electric Industry Co., Ltd.

Claims (1)

[Claims] (1) On at least one side of the insulating film, a) general formula r
:■2c=ct-1,-cooa, (in the formula, R1 is an alkyl group having 2 to 8 carbon atoms) 40 to 800 to 80 parts by weight of acrylonitrile 15 to 50 parts by weight
Parts by weight, and C) monomers 1 to 1 represented by the following general formula;
For 100 parts by weight of an acrylic copolymer consisting of is an alkyl group having 1 to 3 carbon atoms) and/or is a lower layer consisting of a composition containing 1 to 10 parts by weight of a triincyanate represented by the following structural formula; and "double acrylic copolymer", based on O0 parts by weight, as a crosslinking agent, the general formula with e); (wherein, R8 is a hydrogen atom or a methyl group, I19 is -O
fCI-I2-)-mO-Madaha-o+cn, 2-ch
i2-ov. An adhesive layer with a two-layer structure consisting of an upper layer made of a composition containing 01 to 10 parts by weight of a monomer represented by In at least one of the upper and lower layers, based on 100 parts by weight of the copolymer, as a crosslinking agent, f) an alkyl ether represented by the general formula: (wherein n is an integer from 1 to 40) An insulating film having an adhesive layer containing 0.1 to 10 parts by weight of a polyol.