JPH0472869B2 - - Google Patents

Description

[Detailed description of the invention]

In the present invention, one adhesive layer has high adhesiveness and the other adhesive layer has relatively low adhesiveness, and by using the adhesive layer with lower adhesiveness, it can be easily attached to an adherend even once it is attached. Although it can be peeled off, the peeling force when peeling off the release paper laminated to the adhesive layer with lower adhesiveness is almost the same as when peeling the release paper from the adhesive layer with higher adhesiveness. The present invention relates to a method of manufacturing a double-sided adhesive tape having the same or higher quality. Double-sided adhesive tape is used for the purpose of bonding and fixing two adherends together, and takes advantage of the operational advantage that adhesives can bond instantly compared to adhesives, and has a rather strong adhesive force. It has demonstrated its functionality as an industrial adhesive tape. 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. Double-sided adhesive tapes have been developed that can be peeled off again even after being attached to an adherent. 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 directly affects the peel strength of the release paper, so the release paper laminated to the weakly adhesive adhesive layer does not peel off. The release paper may easily shift, wrinkle, or trap air bubbles, and the release paper may peel off before being used as a double-sided adhesive tape, causing dust to adhere to the adhesive layer. There are also some inconveniences. The present inventors conducted research in an attempt to resolve the above-mentioned drawbacks of the prior art, and found that they first coated one side of a tape support with a pressure-sensitive adhesive composition containing a component that reduces adhesiveness, and then exposed it to an electron beam. After irradiating to cause crosslinking and laminating the release paper, apply an adhesive composition that does not contain components that reduce adhesion to the other side, and irradiate the electron beam again. It has been found that the second electron beam irradiation increases the peel strength from the adhesive layer and eliminates the conventional drawbacks. The present invention was made as a result of further research based on the facts discovered in this way.
5 to 70 parts by weight of the following B component, and 0.1 to 0.1 to the following C component
Applying a first composition consisting of 10 parts by weight, then irradiating with an electron beam, and bonding the release surface of the first release paper to the coated surface of the first composition, and then and on the other side of the tape support,
Applying a second composition consisting of 100 parts by weight of the following component A and 5 to 70 parts by weight of the following component B, and after application, irradiating with an electron beam and applying a second composition to the release surface of the second release paper. The gist thereof is a method for producing a double-sided pressure-sensitive adhesive tape, which is characterized by carrying out a step of laminating a composition onto a coated surface. 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 a main component. For example, it is a polymer consisting of a single component of acrylic acid ester realized by the general formula (a); CH ₂ =CHCOOR ¹ (R ¹ is an alkyl group having 2 to 14 carbon atoms). Alternatively, component A may be a copolymer of two or more acrylic esters represented by the above general formula (a) and having different carbon numbers. Furthermore, component A may be a copolymer of 60 to 99 parts by weight of the acrylic acid ester monomer represented by the above general formula (a) and 1 to 40 parts by weight of other vinyl monomers; The vinyl monomer is a vinyl monomer having a carboxyl group, a vinyl monomer having a hydroxyl group, a vinyl monomer having an amino group, styrene, or vinyl acetate. This is the above A component. A polymer containing acrylic ester as a main component is a component directly involved in the adhesive force and cohesive force of the adhesive layer, and is used as a main component in both strongly adhesive and weakly adhesive adhesive compositions. Use as an ingredient. As the A component, the various types mentioned above can be used, but as the A component used in the strong adhesive pressure-sensitive adhesive composition, the acrylic acid ester monomer expressed by the general formula (a) 60
It is preferable to use a copolymer consisting of ~99 parts by weight and 1 to 40 parts by weight of another vinyl monomer, since the adhesive strength and cohesive force can be further increased. In addition, in the above, if the vinyl monomer is less than 1 part by weight, the addition of the vinyl monomer has no effect of improving adhesive strength or cohesive force, and if it exceeds 40 parts by weight, the viscosity of the adhesive composition becomes too high and it is difficult to apply. In addition, when used in combination with component B (described later), the adhesive strength and
Cohesive forces may be difficult to control. (Component B) Component B is an acrylic ester monomer having one acryloyl group in one molecule, and is, for example, an acrylic ester monomer represented by the general formula (a). Or component B is general formula (b);

[Formula] (where R ² is hydrogen or an alkyl group having 1 to 8 carbon atoms,
Or phenyl group, R ³ is hydrogen or carbon number 1
-2 alkyl groups, n is an integer of 1 to 10). Furthermore, the B component has the general formula (C); (However, R ⁴ is hydrogen or an alkyl group having 1 to 2 carbon atoms, R ⁵ is an alkyl group having 1 to 10 carbon atoms, and n is an integer of 1 to 10). In addition, as component B, 2-hydroxy-3
-Phenyloxypropyl acrylate, acryloyloxyethyl monosuccinate, acryloyloxyethyl monophthalate, etc. may be used. The above-mentioned component B plays a role in adjusting the viscosity during application of the adhesive composition, and at the same time forms a polymer together with other components by electron beam irradiation after application, resulting in adhesive strength and cohesion of the adhesive layer. Power can also be controlled. (Component C) Component C is an acrylic 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 one molecule; ethylene glycol diglycidyl ether diacrylate, polyethylene glycol diglycidyl ether diacrylate, propylene glycol diglycidyl ether acrylate, sorbitol tetraglycidyl ether tetraacrylate, glycerol triglycidyl ether triacrylate, etc. In addition, component C may be a condensate of polyhydric alcohol and acrylic acid, such as the following: diethylene glycol diacrylate, neopentyl glycol diacrylate, hexanediol diacrylate, trimethylolpropane triacrylate. , tetramethylolmethanetetraacrylate, etc. Since the above component C is a polyfunctional monomer having two or more acryloyl groups, crosslinking of the coating layer is significantly promoted by electron beam irradiation after coating, which greatly suppresses the adhesive force of the adhesive layer. It is. A weakly adhesive pressure-sensitive adhesive composition is prepared by using the above-mentioned A component, B component, and C component, and a strongly adhesive pressure-sensitive adhesive composition is prepared by excluding the C component and using the A component and B component. be able to. (Weakly Adhesive Adhesive Composition) The weakly adhesive adhesive composition used in the present invention has the following composition. Component A: 100 parts by weight Component B: 5 to 70 Component C: 0.1 to 10 In the above, if component B is less than 5 parts by weight, the viscosity adjustment effect during application by dilution is insufficient;
If it exceeds 70 parts by weight, the viscosity during coating will decrease, but the cohesive force of the adhesive layer will be insufficient even if irradiated with an electron beam after coating. Further, in the above, if the C component is less than 0.1 part 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. Component A: 100 parts by weight Component B: 5 to 70 parts by weight When the parts by weight of component B are outside the above range, the problems are the same as those in the weak adhesive pressure-sensitive adhesive compositions described above. (Tape Support) Any tape support that is generally used as a double-sided adhesive tape support 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, we will discuss the manufacturing method of double-sided adhesive tape using each of the above-mentioned materials.
A uniformly mixed weak adhesive adhesive composition is applied to one side of the tape support. The method of application is arbitrary, but if the viscosity of the weakly adhesive pressure-sensitive adhesive composition is high, the viscosity may be lowered by heating the composition, or
Alternatively, it may be applied by heating and melting. Specific application methods include various roll coating methods, gravure coating methods, extrusion coating methods,
A hot melt coating method using a fountain coater can be used. The amount of the weakly adhesive pressure-sensitive adhesive composition applied to the tape support varies depending on whether or not the tape support is easily penetrated by the composition, but is usually about 10 to 50 g/m ² . 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, when first irradiating an electron beam and then bonding a release paper, the first release paper bonded at this point is not irradiated with an electron beam;
The first release paper is also irradiated with an electron beam only after the strongly adhesive pressure-sensitive adhesive composition described below is applied. After coating, when the first release paper is first attached and then irradiated with an electron beam, the first release paper is irradiated with the electron beam twice in total, including the steps described below. The conditions for electron beam irradiation after applying the weakly adhesive adhesive composition to the tape support include an electron beam acceleration voltage of 100~
The voltage is about 300 kV, and the irradiation dose is 0.1 to 60 Mrad. The electron beam irradiation is preferably carried out in an inert gas atmosphere such as nitrogen gas or carbon 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, and after application, a step of irradiating with an electron beam and a second step are performed. A step of pasting release paper is performed.
Either of the electron beam irradiation step and the second release paper bonding step may be performed first. The coating amount of the strongly adhesive pressure-sensitive adhesive composition and the electron beam irradiation conditions are the same as described above. According to the present invention, since the weakly adhesive pressure-sensitive adhesive composition contains an acrylic acid ester monomer having two or more acryloyl groups, the adhesiveness to other adherends is low (weakly adhesive). In addition to being able to form an adhesive layer, the interface where the weakly adhesive adhesive layer and the release surface of the first release paper are in contact is exposed to electron beams at least when forming the strongly adhesive adhesive layer, or further when forming the weakly adhesive adhesive layer. Since it is irradiated, there is an advantage that it is possible to form an adhesive layer that has weak adhesiveness but has a peel strength of the first release paper that is equal to or higher than that of the second release paper. Furthermore, since the young adhesive pressure-sensitive adhesive composition is subjected to electron beam irradiation twice in total, this reduces the adhesiveness, and there is also the advantage that the adhesiveness can be controlled by changing the electron beam irradiation conditions. Examples are given below to more specifically illustrate the present invention. Example 1 A monomer mixture having the following composition was added dropwise to 40 parts by weight of ethyl acetate under reflux and allowed to react for 6 hours. Monomer mixture 2-ethylhexyl acrylate 60 parts by weight Vinyl acetate 39 〃 α, α′-azobisisobutyronitrile 0.5 〃 Lauryl mercaptan 0.5 〃 Next, add hydroquinone to 500 ppm based on the total amount of the obtained acrylic acid ester copolymer. was added and heated to 140°C to remove the solvent, yielding an acrylic copolymer (). This acrylic copolymer (2) was used and stirred together with other components so as to be homogeneous to obtain a weakly adhesive pressure-sensitive adhesive composition (A) having the following compounding ratio. Adhesive composition (A) Acrylic copolymer () 50 parts by weight lauryl acrylate 45 〃 1,6-hexanediol diacrylate 5 〃 Also, using the acrylic copolymer (), uniformly coated with other components at 120°C A strongly adhesive pressure-sensitive adhesive composition (B) having the following compounding ratio was obtained by stirring the mixture so that the following composition ratio was obtained. Adhesive composition (B) Acrylic copolymer () 85 parts by weight (Toagosei Chemical Co., Ltd., Aronix M113)
10 〃 Acryloyloxyethyl monosuccinate 5 〃 Polyethylene terephthalate film (thickness
First, apply the adhesive composition (A) on one side of the
While heating to 120° C., the coating was applied using a hot melt coater (manufactured by Yuri Roll Machine Co., Ltd., Park Coater) so that the coating amount was 15 g/m ² . After coating, an electron beam is irradiated from the coated surface side at an acceleration voltage of 175 kV and an irradiation dose of 2 Mrad, and then
The release surface of silicone release paper (manufactured by Sanyu Chemical Co., Ltd., K-64H-M white) was attached to the coated surface side, and the film was continuously wound up. Next, apply the above adhesive composition (B) on the side opposite to the side on which the adhesive composition (A) was applied in the same manner as above so that the coating amount is 30 g/m ² . An electron beam was irradiated from the coated side at an acceleration voltage of 175 kV and an irradiation dose of 8 Mrad, and the same release paper as above was laminated and rolled 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.

[Table] Example 2 The same acrylic copolymer () used in Example 1 was stirred at a temperature of 120°C to make it uniform with other ingredients, and a weak adhesive adhesive composition with the following compounding ratio was prepared. Product (C) was obtained. Adhesive composition (C) Acrylic copolymer 65 parts by weight 2-ethylhexyl acrylate 30 1,6-hexanediol diacrylate 5 On the other hand, a strongly adhesive 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. Monomer mixture Butyl acrylate 99.5 parts by weight α,α'-Azobisisobutyronirollyl 0.1 t-Dodecyl mercaptan 0.4 Next, 500 ppm of hydroquinone was added to the obtained copolymer, and the solvent was removed with heating and stirring. An acrylic copolymer () was obtained. This acrylic copolymer () is heated and kneaded with other ingredients to create a highly adhesive adhesive composition.
I got (D). Adhesive composition (D) Acrylic copolymer () 70 parts by weight 2-hydroxyacrylate 20 2-hydroxy-3-phenoxypropyl acrylate 10 Using the adhesive composition prepared as above, polyethylene terephthalate Film (thickness 28μ)
First, the adhesive composition (C) was applied to M) using a park coater at a temperature of 120°C to a coating amount of 15 g/m ² , and after application, an accelerating voltage of 175 kV,
An electron beam was irradiated at an irradiation dose of 5 Mrad, and after the irradiation, release paper (T-80WT-WD, manufactured by Sanyu Chemical Co., Ltd.), which had been subjected to release treatment on both sides, was attached 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 (C) was applied in an amount of 30 g/m ² . From the surface side, acceleration voltage 175kV,
It was irradiated with an electron beam and wound up under conditions of an irradiation dose of 5 Mrad. The adhesive strength of the obtained double-sided adhesive tape and the contact with the adhesive layers on the front and back sides of the release paper are as follows.

【table】

Claims (1)

[Claims] 1. On one side of the tape support, 100% of the following component A is applied.
Parts by weight, 5 to 70 parts by weight of component B below, and 0.1 to 10 parts by weight of component C below,
Next, 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 of the first composition are performed, and then the following A component is applied to the other surface of the tape support. 100 parts by weight and the following B component 5~
70 parts by weight, and after coating, irradiating the first composition and the first release paper together with the second composition with an electron beam; A method for producing a double-sided pressure-sensitive adhesive tape, comprising the step of bonding a release surface to a surface coated with the second composition. Component A; a homopolymer of acrylic esters represented by the general formula CH ₂ =CHCOOR, a copolymer of the acrylic esters with different R, or a vinyl monomer having one or more of the acrylic esters and a carboxyl group. Component B: Acrylic acid ester having one acryloyl group in one molecule. Monomer, component C; acrylic acid ester monomer having two or more acryloyl groups in one molecule. 2 The release surface of the second release paper and the release surface of the first release paper are provided on both sides of the same release paper base paper, and the release surface of the second release paper is 2. 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 while bonding it to the surface to which the second composition is applied.