JPS59157164A - Manufacture of double-coated pressure-sensitive adhesive tape - Google Patents

Abstract

PURPOSE:To improve the peel strength of a releasing paper from a tape substrate, by coating a surface of the substrate with a specific pressure-sensitive adhesive having low adhesivity, irradiating the adhesive with electron radiation, laminating the objective releasing paper to the surface, coating the other surface of the substrate with a pressure-sensitive adhesive having high adhesivity, irradiating the adhesive with electron radiation, and laminating the second releasing paper to the second adhesive. CONSTITUTION:A surface of a tape substrate is coated with a composition composed of (A) 100pts.wt. of a (co)polymer of acrylic acid ester of formula or a copolymer of said acrylic acid ester and a vinyl monomer, (B) 5-70pts.wt. of an acrylic acid ester monomer having one acryloyl group in the molecule, and (C) 0.1-10pts.wt. of an acrylic acid ester monomer having two or more acryloyl groups in the molecule. The coating layer is irradiated with electron radiation, and the first releasing paper is laminated to the coated layer. The other surface of the substrate is coated with a composition composed of 100pts.wt. of the above component (A) and 5-70pts.wt. of the component (B), irradiated with electron radiation, and laminated with the second releasing paper to obtain the objective tape. EFFECT:The peel strength of the first releasing paper can be improved to a level comparable to or higher than that of the second releasing paper even by using a weak adhesive.

Description

DETAILED DESCRIPTION OF THE INVENTION According to the present invention, one adhesive layer has high adhesiveness and the other adhesive layer has relatively low adhesiveness. Even though it can be easily peeled off once it is pasted, the peeling force when peeling off the release paper that is laminated to the adhesive layer with lower adhesiveness is higher than that of the adhesive layer with higher adhesiveness. Peel-off double-sided adhesive tape is used for the purpose of adhering and fixing two adherends together. It has demonstrated its functionality as an industrial adhesive tape with strong adhesive strength.

By the way, in recent years, unlike the above-mentioned double-sided adhesive tape, one of the adhesive layers on both sides has weak adhesiveness and the other has strong adhesiveness, and when the weakly adhesive adhesive layer is used, Double-sided adhesive tapes have been developed that can be peeled off again even after being adhered to an adherend. In this way, double-sided adhesive tape, which can be bonded and re-peelable on one side, is used as a substitute for thumbtacks, for fixing posters and memo paper, for sealing plastic and paper bags, etc., and has the advantage that it does not destroy the adherend when re-peeling. There is.

However, in conventional double-sided adhesive tapes of this type, the difference in the degree of adhesion on both sides is directly equivalent to the difference in the peel strength of the release paper, so the release paper laminated to the weakly adhesive adhesive layer is There are inconveniences such as the release paper slipping off, wrinkled, and trapping air bubbles.Also, the release paper peels off before being used as a double-sided adhesive tape and dust adheres to the adhesive layer. There are some inconveniences.

The present inventors conducted research in an attempt to eliminate the above-mentioned drawbacks of the prior art, and found that first, a pressure-sensitive adhesive composition containing a component that reduces adhesiveness was applied to one side of a tape support, and then irradiated with an electron beam. After cross-linking is caused and laminated with release paper, an adhesive composition that does not contain any components that reduce adhesion is applied to the other side and irradiated with an electron beam again.
It has been found that when a release paper that has already been laminated is irradiated with an electron beam a second time, its peel strength from the adhesive layer is increased, and the drawbacks of the prior art are overcome.

The present invention was made as a result of further research based on the facts discovered in this way, and on one side of the tape support, 100 parts by weight of the following human component and 5 to 70 parts of the following B component
parts by weight, and 0.1 to 10 parts by weight of component C below, followed by irradiating with an electron beam and applying the first composition to the release surface of the first release paper. Then, 100 parts by weight of the following component A and 5 to 5 parts of the following component B are applied to the other surface of the tape support.
After application, a second composition consisting of 76 parts by weight is applied;
The gist thereof is a method for producing a double-sided adhesive tape, which comprises the steps of irradiating with an electron beam and bonding the □ release surface of a second release paper to the surface coated with the second composition. be. □ First, component A, component B, and component -C that constitute the adhesive composition used in the present invention, as well as a composition using them, a tape support, and a release paper will be individually explained.

(Component A) Component A is a polymer containing acrylic ester as the main component. For example, the general formula (a): CH9L= CHCOOR"('R' is a carbon number of 2 to
It is a polymer consisting of 11-components of acrylic esters expressed by 14 alkyl groups). Alternatively, the A component may be a copolymer of two or more acrylic esters having different carbon numbers, expressed by the above general formula (al). Furthermore, the A component may be expressed by the above general formula (a). It may be a copolymer of 60 to 99 parts by weight of an acrylic acid ester monomer and 1 to 40 parts by weight of another vinyl monomer,
Here, other vinyl monomers include carboxyl group, hydroxyl group,
Alternatively, it is a vinyl monomer having an amino group, or styrene or vinyl acetate.

The above component A, a polymer mainly composed of acrylic ester, is a component that is directly involved in the adhesive force and cohesive force of the adhesive layer, and is a component that is directly involved in the adhesive force and cohesive force of the adhesive layer, and is used as a strong adhesive adhesive composition and a weak adhesive adhesive composition. It is used as a main component in all compositions. As component A, the various types described above can be used, but as component A used in the strongly adhesive pressure-sensitive adhesive composition, 60 to 99 parts by weight of an acrylic acid ester monomer expressed by the general formula (al) It is preferable to use a copolymer consisting of 1 to 40 parts by weight of another vinyl monomer because it can further increase the adhesive force and cohesive force.In the above, if the vinyl monomer is less than 1 part by weight, Addition of a vinyl monomer has no effect on improving adhesive strength or cohesive strength, and if the amount exceeds 40 parts by weight, the viscosity of the adhesive composition may become too high, making it difficult to apply. Difficult to control adhesive strength and collective force when used in combination with component B (
Sometimes it happens.

(Component B) Component B is an acrylic acid ester monomer having one acryloyl group in one molecule, for example, the general formula (
It is an acrylic acid ester monomer indicated by al. Alternatively, component B may be a monomer represented by the general formula (b); where R5 is hydrogen or an alkyl group having 1 to 2 carbon atoms, 5n is an integer of 1 to 10. Furthermore, the B component has the general formula (C
); (However, R4 is hydrogen or an alkyl group having 1 to 2 carbon atoms, R5 is an alkyl group having 1 to 10 carbon atoms, and n is 1 to 1
It may be a monomer expressed as an integer of 0). In addition, the B component may be 2-hydroxy-3-phenoxypropyl acrylate, acryloyloxyethyl monophthalate, acryloyloxyethyl monophthalate, or the like.

The above-described component B plays a role in adjusting the viscosity of the adhesive composition during application, and at the same time forms a polymer together with other components by electron beam irradiation after application, thereby improving the adhesive strength of the adhesive layer.
Cohesion can also be controlled.

(Component C) Component C is an acrylic acid ester monomer having 2 to 4 acryloyl groups in one molecule.

Component C is, for example, the following compound obtained by adding acrylic acid to a polyepoxy compound having two or more epoxy groups in the molecule; ethylene glycol diglycidyl ether di-acrylate, polyethylene glycol diglycidyl Ether diacrylate, propylene glycol diglycidyl ether acrylate, sorbitol tetraglycidyl ether diacrylate, glycerol triglycidyl ether triacrylate, etc. .

This LC component may be a condensate of polyhydric alcohol and ac7lic acid, such as the following; Trimethylolp10ban triacrylate, tetramethylolmethanetetraacrylate, etc. ・Since the above C component is a polyfunctional monomer having two or more acryloyl groups, electron beam irradiation after coating may cause crosslinking of the coating layer. As a result, the adhesive force of the pressure-sensitive adhesive layer is greatly suppressed.

By using the above-mentioned A component, B component, and C component, a weak adhesive pressure-sensitive adhesive composition can be obtained, and by using the A component and B component, excluding the C component, a strong adhesive pressure-sensitive adhesive composition can be obtained. can be prepared.

(Weakly Adhesive Adhesive Composition) The weakly adhesive adhesive composition used in the present invention has the following composition.

If the above odor is less than 5 parts by weight, the viscosity adjustment effect during application will be insufficient, and if it exceeds 70 parts by weight, although the viscosity during application will decrease, electron beam Even after irradiation, the cohesive force of the adhesive layer is insufficient.

Furthermore, in the above, if the C component is less than 0.1 parts by weight, there is almost no effect of suppressing the adhesive force, and if it exceeds 10 parts by weight, the cohesive force becomes too high and the adhesive force disappears.

(Strong adhesive pressure-sensitive adhesive composition) The strong adhesive pressure-sensitive adhesive composition used in the present invention has the following composition.

The problems when the weight part of component B is out of the above range are the same as those in the weakly adhesive adhesive composition described above. (Tape support) The tape support is generally used as a double-sided adhesive tape support. Any of the currently used ones can be used. For example, nonwoven fabrics of various fibers, cloth, paper, plastic films, metal foils, or composites of these materials can be used as the tape support.

(Release Paper) As the release paper, the most common silicone release paper, polyolefin release paper, or paraffin release paper can be used.

Next, a method for manufacturing a double-sided adhesive tape using each of the above-mentioned materials will be described. First, a weakly adhesive adhesive composition uniformly mixed on a tape support is coated on one side of the tape support (fh). The method of application is arbitrary, but when the viscosity of the weakly adhesive pressure-sensitive adhesive composition is high, it is preferable to heat the composition to lower the viscosity, or to apply it by heating and melting the composition. Specific examples of coating methods that can be used include various roll coating methods, gravure coating methods, extrusion coating methods, and hot melt coating methods using a fountain coater.

Application I of the weakly adhesive pressure-sensitive adhesive composition to the tape support consists of:
Although it depends on whether or not the tape support is permeable to the composition, it is usually about 10 to 502 degrees.

After applying the weakly adhesive pressure-sensitive adhesive composition to the tape support, a step of irradiating with an electron beam and a step of bonding the release surface of the first release paper to the coated surface are performed. After coating, first irradiate with an electron beam and then attach a release paper.At this point, the first release paper that has been pasted is not irradiated with the electron beam, and the strong adhesion described below is maintained. The first release paper is also irradiated with an electron beam only after the adhesive composition is applied. After coating, when first attaching the first release paper and then irradiating the electron beam, the first release paper will be attached to the second release paper in total, including the process described below.
The patient is exposed to multiple electron beam irradiations. The conditions for electron beam irradiation performed after applying the weakly adhesive pressure-sensitive adhesive composition to the tape support include an electron beam acceleration voltage of about 100 to 300 kV, and an irradiation rate of 0.1 to 5 Q Mrad. The electron beam irradiation is preferably carried out in an inert gas atmosphere such as nitrogen gas or carbon dioxide gas. .

Next, a strongly adhesive adhesive composition is applied to the opposite side of the tape support to the side on which the weakly adhesive adhesive composition is applied,
゛After coating, the step of irradiating with electron beam and applying the second release paper
A process of matching the horoscope is performed. Electron beam irradiation process and second
The step of pasting the release paper can be carried out at any point. The coating amount of the strongly adhesive pressure-sensitive adhesive composition and the electron beam irradiation conditions are the same as described above.

In addition, since the weakly adhesive pressure-sensitive adhesive composition of the present invention contains an acrylic acid ester monomer having two or more acryloyl groups, it has low adhesiveness to other adherends (weakly adhesive). ) It is possible to form an adhesive layer, and at the interface where the weakly adhesive adhesive □ layer and the release surface of the first release paper are in contact, electronics may be applied at least when forming the strongly adhesive adhesive layer, or further when forming the weakly adhesive adhesive layer. Because the line is irradiated, the peel strength of the first release paper is the same as that of the second release paper, although the adhesive strength is weak.
It has the advantage of being able to form an adhesive layer with an improved peel strength equal to or greater than that.

In addition, since the weakly adhesive pressure-sensitive adhesive composition is exposed to electron beam irradiation twice in total, this reduces the adhesiveness, which also has the advantage that the adhesiveness can be controlled by changing the electron beam irradiation conditions. be.

Examples are given below to more specifically illustrate the present invention.

Example 1 A monomer mixture having the following composition was dropped into 40 parts by weight of refluxing ethyl acetate and reacted for 6 hours.

Next, hydroquinone was added in an amount of 500 ppm based on the total amount of the obtained acrylic ester copolymer, and the solvent was removed by heating to 140° C. to obtain an acrylic copolymer <I).

This acrylic copolymer (11) was used and stirred together with other components so as to be uniformly distributed to obtain a weakly adhesive pressure-sensitive adhesive composition (A) 4 having the following compounding ratio.

Further, acrylic copolymer (I) was used and stirred together with other components at 120° C. so as to be uniform, to obtain a strongly adhesive pressure-sensitive adhesive composition (B) having the following compounding ratio.

Polyethylene terephthalate film (J12-8μ,
First, apply the adhesive composition (N at a temperature of 120°C) to one side of the
The coating was applied using a hot melt coater (5 Park Coater manufactured by Jiri Roll Kikai Co., Ltd.) while heating to 157°C.

After coating, an electron beam was irradiated from the coated side under the conditions of an acceleration voltage of 175 kV and an irradiation dose of 2 Mrad, and then silicone release paper (manufactured by Sunny Chemical Co., Ltd., K-54H) was applied to the coated side.
-M white) was continuously wound up while bonding the peeled surfaces together.

Next, on the side opposite to the side on which the adhesive composition (phase) was applied, apply the above adhesive composition (Bl) in the same manner as above so that the coating amount is 309 Ar?, and from,
It was irradiated with an electron beam under the conditions of an acceleration voltage of 175 kV and an irradiation beam of M8 Mrad, and the same release paper as above was laminated and wound up.

The peel strength of the release paper on the front and back sides of the obtained double-sided adhesive tape and the adhesive strength of the adhesive layers on the front and back sides were as follows.

■・・・According to JIS Z 0237.

■ Initial peel strength at a tensile speed of 1000 R7 min Both ■ and ■ have units of P/25 am width Example 2 Using the same acrylic copolymer (1) as used in Example 1, The mixture was stirred at a temperature of 120° C. so as to be uniform with other components to obtain a weakly adhesive adhesive composition (C1) having the following compounding ratio.

On the other hand, a strongly adhesive pressure-sensitive adhesive composition was prepared as follows.

An acrylic acid ester monomer mixture having the following composition was dropped into refluxing ethyl acetate, and after the dropwise addition was completed, the mixture was heated for 6 hours to react.

Next, 50% of hydroquinone was added to the obtained copolymer.
0 ppm was added, and the solvent was removed while stirring under heat to obtain an acrylic copolymer (U).

This acrylic copolymer (...) was heated and kneaded with other components to obtain a strongly adhesive adhesive composition (Dl).

Using the adhesive composition prepared as above, it was coated at ℃ using a park coater so that the coating amount was 159/d. After irradiation with electron beam under certain conditions, release paper (manufactured by Sunny Chemical, T-8) with release treatment on both sides was used.
0WT-WD) were pasted together and rolled up.

Next, apply the above adhesive composition (D) to the surface of the polyethylene terephthalate film opposite to that on which the adhesive composition (q) was applied at a coating amount of 30 !i'/m2, An electron beam was irradiated from the coated surface side under the conditions of an acceleration voltage of 175 kV and an irradiation acid of 5 Mrad, and the film was wound up.

The adhesive strength of the obtained double-sided adhesive tape and the peeling strength between the adhesive layers on the front and back sides of the release paper are as follows.

Measurement conditions 7, units are the same as Example 1

Claims (2)

[Claims] (1) On one side of the tape support, 100 parts by weight of component A below, 5 to 70 parts by weight of component B below, and 0.0 parts by weight of component C below.
A step of applying a first composition consisting of 1 to 10 parts by weight, and then irradiating with an electron beam, and a step of bonding the release surface of the first release paper to the surface coated with the first composition are performed. Then, on the other side of the tape support, a second composition consisting of 100 parts by weight of the following component and 5 to 70 parts by weight of the following component B is applied, and after application, it is irradiated with an electron beam. step and second
A method for producing a double-sided adhesive tape, comprising the step of laminating the release side of release paper to the coated side of the second composition. Component A; 'A homopolymer of acrylic esters represented by the general formula CH, == CHCOOR, a copolymer of the acrylic esters having different R, or one or more of the acrylic esters and a carboxyl group, A vinyl monomer having a hydroxyl group or an amino group, or a copolymer with one or more types of styrene or vinyl acetate, component B; and an acrylic acid ester monomer having one acryloyl group in one molecule, component C; one molecule. An acrylic acid ester monomer containing two or more acryloyl groups. (2) The release surface of the second release paper and the release surface of the first release paper are respectively provided on both sides of the same release paper base paper. After performing the step of laminating the release surface to the application surface of the second composition,
The method for producing a double-sided pressure-sensitive adhesive tape according to claim 1, further comprising the step of winding up the entire tape.