JPS6210180A - Method of peeling adhesive film for surface protection - Google Patents

Abstract

PURPOSE:To make a peeling work easy and prevent transfusion of an adhesive into an adherend, by bonding a particular adhesive film contg. a radiation- curable liq. resin to an adherend and curing the adhesive layer after use to peel the film. CONSTITUTION:An adhesive film on which an adhesive obtd. by blending 100pts. wt. acrylic copolymer having a glass transition temp. of -30-30 deg.C with 20-200 pts.wt. radiation-curable polyfunctional liq. resin has been the adhesive film has been bonded is transported, processed or cut. At this time, the adhesive film serves for temporary protection of the adherend such as prevention of flaw and contamination and protection. Thereafter, the surface of the base material of the adhesive film is exposed to radiation, thereby curing the adhe sive. The adhesive film is peeled off. Examples of the radiation-curable polyfunctional liq. resin include 1,4-butanediol diacrylate and triallyl cyanurate.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is useful for preventing scratches and contamination during transportation, processing, and cutting of coated objects such as metal plates, aluminum sashes, plastic plates, semiconductor wafers, and glass, and for preserving them. Temporary surface protection for VC#
This article relates to a method for peeling off a sticky N film for surface protection.

[Conventional technology]

Conventionally, adhesive films have been used as temporary surface purulent retention materials, which are made by coating a base material such as paper, cloth, or plastic film with an adhesive mainly composed of natural rubber, synthetic rubber, or the like.

Although this adhesive film is widely used because of its ease of lamination, it has the following drawbacks because the adhesive is extremely unstable and the material is easily deformed.

(1) After being attached to an adherend, the adhesive flows well into the fine recesses on the surface of the adherend and increases the contact area, so the adhesive force becomes too strong in a short period of time, causing it to peel off and dry.

(2) Because the cohesive force is small, when the adhesive layer is peeled off, the adhesive layer is likely to break and be transferred onto the layered body.

To address these drawbacks of adhesive films, proposals have been made to suppress the plastic deformation of the adhesive to some extent by crosslinking the adhesive, using high molecular weight rubber, and increasing the cohesive force. The above-mentioned drawbacks have basically not been solved under the condition that it can be easily attached to a coating at room temperature. Generally, when an adhesive film is applied industrially to an adherend, the fIJN direction required is 1800 directions and 500
When peeled at a speed of 1111/min, rc is 50 g/25 mm or more even for simple protection during transportation, and rc is 200 g/25 or more when performing all processing such as bending and drawing.
500g/25 for full cut processing of IC wafers, etc.
mm or more is also required.

On the other hand, from the standpoint of peeling workability, the lower the value, the better, and if it exceeds 200 g and 725 mm, it will be difficult to peel.
It's getting c. The adhesive strength of the adhesive film is set by setting the minimum adhesive strength required at the time of application, but since the time from processing to peeling depends on various process routes, it is difficult to set the adhesive strength for a long time and when peeling. The adhesive strength of the adhesive is usually higher than that during processing, making the peeling process more difficult and making it easier for the adhesive to transfer onto the adherend.

Therefore, as proposed in Japanese Patent Publication No. 58-50164, the present inventors attached an adhesive film made of a transparent plastic film base coated with an adhesive having Vc-curing property to an adherend and used it for use. After that, the surface of the film base material is fully irradiated with ultraviolet rays to crosslink and cure the adhesive.
It has been found that removability is improved.

However, with the increasing sophistication of drawing processing, and the recent progress and automation of the electronics industry, the Yasugi characteristics of surface protection films have also become higher, and it may become difficult to meet these demands at the conventional level.

[Problem that the invention seeks to solve]

The present invention was developed in view of the deteriorating situation, and its purpose is to make it easy to attach to adherends, to maintain strong adhesive blades during storage, transportation, processing, and cutting, and to peel off after use. A method for peeling an adhesive film for surface protection, which greatly reduces the contact force when applying the adhesive, makes the peeling work easier by eliminating negative VC, and prevents the adhesion of adhesive onto the adherend. It's all about providing.

[Child actor to decide on issues]

According to the present invention, the purpose is to provide a substrate with a glass transition point of -3.
Acrylic copolymer 1 with VC in the range of 0°C to 50”C
Multifunctional liquid resin 2 that is radiation-curable to part 00iii
Achieving VC Niji by applying radiation to the surface of the base material to cure the adhesive after applying an adhesive film completely coated with 0 to 200 parts by weight of adhesive to an adherend and applying VC. I can do it.

That is, the adhesive is a conventional adhesive (general W- is Tg = -6
After being used as an acrylic thread copolymer having a Tg higher than 0°C to -60°C and having almost no tackiness at room temperature, the polyfunctional liquid resin is polymerized, crosslinked and cured by irradiation with radiation.

The acrylic copolymer used in the present invention is mainly composed of (meth)acrylic ester-based polymers, and monomers having a haalkyl group having 1 to 12 carbon atoms are preferable, and particularly advantageous ones are ethyl acrylate,
These include butyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, butyl methacrylate, and the like.

In addition, as functional monomers, acrylic acid, methacrylic acid,
Copolymerization of hydroxide diethyl acrylate, hydride Ω-xypropyl methacrylate, acrylamide, N-methyl 0-ylacrylamide, etc. for complete crosslinking is also possible.

Other vinyl monomers such as rn&vinyl, acrylonitrile, and styrene are also used for Tg adjustment.

On the other hand, in the sense of adjusting the cohesive force, unsaturated double bonds in one molecule of the above-mentioned acrylic co-N-association can be reduced by VC compared to conventional methods (e.g., epoxy-acid reaction, -utilization of urethane, etc.). You can also do that.

In addition, the above-mentioned Tg is the xi of the constituent monomers of the copolymer.
This is a value calculated from the i ratio according to the formula of Gorden-Taylo&. Generally, VC is measured using a dynamic viscoelastic device, differential thermal analysis, or the like.

The Tg4-1 knee is in the range of 3.0°C to 30°C, preferably 1-10°C to 20°C. If the temperature is lower than -50°C, the adhesive remains sticky even after radiation irradiation, and the adhesive strength is less reduced and the effect is low. This is because if the temperature exceeds 50°C, the sliding force will be low and the adhesion to the adherend will be poor.

The radiation-curable polyfunctional liquid resins that are essential components of the adhesive of the present invention include di-1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, diethylene glycol diacrylate, and polyethylene glycol diacrylate (n= 3-14)) Acrylate monomers such as rimethylol globan triacrylate, triallyl cyanurate, pentaerythritol tetraacrylate and the corresponding methacrylate monomers are mainly mentioned.

In addition, the main button is a (meth)acrylic acid alkyl ester, polyol, polyester, urethane, epoxy, etc. oligomer having one or more (meth)acryloyl groups in the terminal or side chain in the molecule. It is usually liquid and includes those with a viscosity of 10'cps or less at room temperature.

In order to improve the cohesive force of the above-mentioned adhesive, cross-linking agents such as incyanate and melamine should not be added, and if necessary, tackifiers, softeners, antioxidants, fillers, pigments, etc. may all be mixed in. There are cases.

A pressure-sensitive adhesive having these structures is applied to a film base material using a conventional method such as a roll coater to obtain a pressure-sensitive adhesive film. In addition, if the cohesive force is insufficient, a release paper may be interposed and the film may be wound up. Attach this adhesive film to the adherend, transport it,
If radiation is irradiated before peeling after holding, processing, cutting, etc., the unsaturated double bonds, which are functional groups, will react, and the polymerized 2K, strainer, and adhesive will solidify through polymerization, crosslinking, etc. death,
This lowers the adhesive strength and makes it extremely difficult for transfer to occur. The reason for the decrease in sliding force is thought to be that the amount of work due to plastic flow is reduced.

Note that the radiation mentioned above refers to active energy rays, including alpha rays, beta rays,
T-rays, neutron beams, accelerated electron beams, radiation, and ultraviolet #5! say.

These irradiations are performed throughout the base film,
Since oxygen in the air is naturally blocked, the curing reaction proceeds quickly.

Furthermore, in the case of ultraviolet rays, the base material is limited to transparent plastic films such as polyethylene, polyvinyl chloride, and polyester in terms of transparency.

In addition, as a curing accelerator, a sensitizer such as benzyl, benzophenone, benzoin, benzoin ethyl ether, etc. is often mixed in an amount of vc1-2ON in the adhesive.

The present invention will be further explained below with reference to Examples.

Examples 1 to 7 In the monomer composition, X part of acrylonitrile, 7 parts of butyl acrylate (however, x+y=95s) and 5 parts of acrylic acid as K functional group, Gorden -Tay to! According to the formula of i, Tg is -50℃, -20'C1-10℃, 0℃
, 10℃, 20℃, 50℃ emulsified N with 7 types of preparation notes
The acrylic rubber with a molecular weight of approximately 500,000 was completely synthesized. An adhesive prepared by adding 100 parts of the acrylic rubber, 5 parts of polyfunctional incyanate (manufactured by Nippon Polyurethane ■, trade name Coronate L), 100 parts of trimethylolpropane triacrylate, and 10 parts km of benzophenone was diluted in a 5% toluene solution. The adhesive film was coated on a 60 μm polyethylene film using a top reverse roll coater so that the solid content amount was 10 μm, and dried at 100° C. for 5 minutes to produce an adhesive film.

This adhesive film was temporarily attached to SO5 having a thickness of α6 mm at room temperature, and then left for one month. Ultraviolet rays were irradiated on the film surface of this SUS board for 15 seconds using a 2kW commercial mercury lamp.
It was peeled off after 0 minutes.

The adhesive strength at each stage and the surface of the adherend after peeling were investigated. Furthermore, thickness Q, 5mo+ size 5mm x 5Qmm S
When pasting on the US board, we conducted an Erichsen drawing test with a depth of 8 degrees.
The surface condition after peeling was treated with the same ultraviolet rays (i%).

The above characteristic results are summarized in Table 11/c.

Comparative Example 1.2 Acrylic rubber with Tg = -40°C and +40°C was synthesized using the monomer composition of Example 1 in the same manner. It was manufactured and all characteristic tests were carried out.

1'l'l-White Examples 8 to 14 Rush 91] Acrylic rubber 1 to 7 100 f+AS, 6 parts of polyfunctional incyanate, trifunctional oligomer (Toa Amano Chemical 4?n'N, trade name Aloex M-8060)
A slate agent containing 100 parts of benzophenone and 10 parts of benzophenone was applied to a polyester film having a total thickness of 40 µm, and 15 VC was applied to the solid content coating thickness to 20 µm to prepare an adhesive film. This ioam+nφ wafer, on which the adhesive film VC circuit was completely formed, was attached to a circuit board whose circuit surface would be used for road use, and a 50,000 R
Full cut with PM diamond rotation, iQn+
m chips were obtained. The chip was peeled from the adhesive film using JA air absorption VCX after irradiation with ultraviolet rays.

Ratio 4 parts 2 Examples 6.4 Examples 8 to 14 to the acrylic rubber gold paste of Comparative Example 1.2
A polyester-based adhesive film was prepared in the same manner as above, and used for dicing in the same manner.

Table 2 shows the results of VC.

As described above, a surface-retaining adhesive film made of a high Tg acrylic copolymer and a multifunctional liquid resin is attached to an adherend, and it is irradiated with radiation before being peeled off after being used for transportation and processing. However, by curing the adhesive, the releasability, which was a drawback of conventional adhesive films, has been significantly improved, and it has become possible to almost eliminate transfer of the adhesive N agent.

Claims (1)

[Claims] 1. Adhesive made by applying an adhesive containing 20 to 200 parts by weight of a radiation-curable polyfunctional liquid resin to 100 parts by weight of an acrylic copolymer with a glass transition point in the range of -30°C to 30°C. Peeling of an adhesive film for surface protection, characterized in that after the film is attached to an adherend and used, the adhesive is cured by irradiating the base material surface of the adhesive film with radiation, and then peeled off. Method.