JP2005320553A - Method and apparatus for producing pressure-sensitive adhesive tape - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a pressure-sensitive adhesive tape having a pressure-sensitive adhesive layer free from thickness unevenness by irradiating a pressure-sensitive adhesive composition with an energy beam to perform a polymerization reaction. <P>SOLUTION: In this method for producing the pressure-sensitive adhesive tape having the pressure-sensitive adhesive layer formed by irradiating the pressure-sensitive adhesive composition with the energy beam to perform the polymerization reaction, the thickness of the pressure-sensitive adhesive composition is regulated by a thickness controlling means during a time after the irradiation of the pressure-sensitive adhesive composition with the energy beam is started and before the polymerization reaction of the pressure-sensitive adhesive composition is completed. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for producing a pressure-sensitive adhesive tape having no variation in the thickness of the pressure-sensitive adhesive layer.

  Conventionally, as shown in FIG. 1, a double-sided pressure-sensitive adhesive tape 1a having a structure in which an adhesive layer 4 is sandwiched between base films 3 and 5 (hereinafter simply referred to as a release film) subjected to a release treatment has been widely known. In such a pressure-sensitive adhesive layer 4, a pressure-sensitive adhesive composition containing an acrylic monomer as a main component is coated on the release film 3 in a layered manner, and the coating film is irradiated with energy rays such as ultraviolet rays and electron beams to cause a polymerization reaction. It is formed by.

  The double-sided pressure-sensitive adhesive tape 1a in FIG. 1 is called a “non-support type pressure-sensitive adhesive tape” from the viewpoint of distinguishing from the double-sided pressure-sensitive adhesive tape 1b in which the pressure-sensitive adhesive layer 4 is formed on both surfaces of the base film 6 as shown in FIG. is there.

  Said adhesive tape 1a can be manufactured with the manufacturing apparatus 100 like FIG. Here, the coating apparatus 100 includes a coating unit 40 that coats the pressure-sensitive adhesive composition and an irradiation unit 70 that radiates ultraviolet rays as energy rays, and further includes an unwinding unit 30 that feeds the release film 3 and the release film 5. And a winding unit 90 that winds up the adhesive tape 1a on which the pressure-sensitive adhesive layer 4 is formed.

  The manufacturing process of the adhesive tape 1a of FIG. 1 will be described using the coating apparatus 100.

  First, the release film 3 is drawn out to the application unit 40 from the web 34 of the release film 3 attached to the unwinding shaft 32 of the unwinding unit 30.

  The application unit 40 includes a pair of an upper surface roll 42 and a lower surface roll 44, and a dam 46 for supplying the adhesive composition 4 a is attached to the lower surface roll 44.

  A predetermined gap 48 is formed between the upper surface roll 42 and the lower surface roll 44, and the adhesive composition 4 a is applied onto the release film 3 when the release film 3 passes through the gap 48. Yes.

  Next, the release film 5 is pulled out from the release film web (not shown), placed on the pressure-sensitive adhesive composition 4 a, and the gap between the upper surface roll 52 and the lower surface roll 54 disposed in a pair of the laminated portions 50. When passing through 58, the release film 5 is laminated on the pressure-sensitive adhesive composition 4a.

  The release film 3 in which the pressure-sensitive adhesive composition 4a and the release film 5 are laminated is conveyed to an irradiation unit 70 that emits ultraviolet rays. Here, the irradiation unit 70 is provided with a support roller 73 that supports movement of the release film in a metal irradiation chamber 71 and a light source lamp 72 that irradiates ultraviolet rays as energy rays. The pressure-sensitive adhesive composition 4a on the release film 3 conveyed into the irradiation chamber 71 is irradiated with ultraviolet rays from the light source lamp 72, thereby starting a polymerization reaction, and becomes the pressure-sensitive adhesive layer 4 after the polymerization reaction is completed.

  The intensity of the ultraviolet light of the light source lamp 72 is set so that the polymerization reaction is almost completed while the pressure-sensitive adhesive composition 4 a passes through the irradiation chamber 71.

  Next, the release film 3 on which the pressure-sensitive adhesive layer 4 has been formed is unloaded from the irradiation unit 70 and taken up by the take-up shaft 92 of the take-up unit 90 to form an adhesive tape web 94. Next, the target adhesive tape 1a can be obtained by cutting the web 94 into a predetermined size.

  In addition, using the manufacturing apparatus 101 of FIG. 9, after the adhesive layer 4 is formed, the release films 3 and 5 are peeled off by the release rolls 96 and 96 ′, and the printed film 3 ′ and the like printed. Often, 5 ′ is newly laminated by the laminating rolls 98 and 98 ′ to produce an adhesive tape 1c having an increased commercial value as shown in FIG.

  Moreover, if the peeling film 3 is replaced with the base film 6 using the manufacturing apparatus of FIG. 8, the single-sided adhesive tape 1d as shown in FIG. 4 can be obtained.

  The pressure-sensitive adhesive tape having a pressure-sensitive adhesive layer polymerized by energy rays such as ultraviolet rays does not use an organic solvent in the production process, and therefore does not cause deterioration of the working environment due to the organic solvent. As it shows strength, further demand is expected in the future.

  However, the conventional manufacturing method for manufacturing an adhesive tape using the manufacturing apparatus shown in FIGS. 8 and 9 has a problem that the thickness of the pressure-sensitive adhesive layer 4 is uneven and easily peeled off.

  An object of the present invention is to provide a method for producing a pressure-sensitive adhesive tape having a pressure-sensitive adhesive layer having no thickness unevenness by irradiating the pressure-sensitive adhesive composition with an energy ray to cause a polymerization reaction.

  In order to eliminate the occurrence of variation in the thickness of the pressure-sensitive adhesive layer due to the swelling, the adhesive composition is polymerized in order to eliminate the variation. In order to complete the present invention, it has been found that the thickness of the layered pressure-sensitive adhesive composition may be forcibly adjusted by pressing the “bulge” in the irradiated portion between the start and the completion of the reaction. It came.

That is, the present invention applies an adhesive composition on a tape-like substrate, further laminates a release film on the adhesive composition, and an adhesive sandwiched between the tape-like substrate and the release film. In the method for producing a pressure-sensitive adhesive tape having a pressure-sensitive adhesive layer formed by irradiating the agent composition with an energy ray to cause a polymerization reaction,
After the irradiation of the energy ray is started to the pressure-sensitive adhesive composition sandwiched between the tape-shaped substrate and the release film, the pressure-sensitive adhesive composition is until the polymerization reaction of the pressure-sensitive adhesive composition is almost completed. When adjusting the thickness by the thickness control means, a pair of rolls having a predetermined gap is used as the thickness control means, and the thickness adjustment is performed by passing the adhesive composition between the pair of rolls. A featured manufacturing method is provided.

  The present invention also includes an application means for applying a pressure-sensitive adhesive composition to a tape-shaped substrate, a lamination means for further laminating a release film on the pressure-sensitive adhesive composition on the tape-shaped substrate, and a pressure-sensitive adhesive composition comprising a release film. A pressure-sensitive adhesive tape manufacturing apparatus comprising at least irradiation means for irradiating an energy ray to a laminate sandwiched between a tape and a tape-like base material, and polymerizing the pressure-sensitive adhesive composition to form a pressure-sensitive adhesive layer The thickness control means for adjusting the thickness of the pressure-sensitive adhesive composition is applied to the irradiation means until the polymerization reaction of the pressure-sensitive adhesive composition is almost completed after the irradiation of the energy ray to the pressure-sensitive adhesive composition is started. Provided is a manufacturing apparatus which is provided.

  As the thickness control means in the present invention, various apparatuses can be used depending on the degree of progress of polymerization of the pressure-sensitive adhesive composition, fluidity, pressure-sensitive adhesive force, cohesive force and the like. For example, a doctor blade, a tension roll that applies tension between adjacent guide rolls, a pair of smooth rolls or emboss rolls having a predetermined gap, a gravure plate, and the like can be used. Here, examples of the thickness adjustment by the thickness control means include a case where the surface of the pressure-sensitive adhesive composition is flattened so as to have a uniform thickness, and a case where minute irregularities are intentionally formed on the surface. it can. Among these, it is preferable to use a pair of smooth rolls having a predetermined gap from the viewpoint that the layer thickness of the pressure-sensitive adhesive composition can be made uniform more easily.

  Hereinafter, the manufacturing method of the adhesive tape of this invention is demonstrated using the manufacturing apparatus (an example of the manufacturing apparatus of this invention) of FIG.

  The manufacturing apparatus 300A of FIG. 5 is a conventional adhesive tape manufacturing apparatus 100 except that a thickness control roll unit 80 including a pair of upper surface roll 82 and lower surface roll 84 having a predetermined gap 86 is disposed as a thickness control means. The basic configuration is the same as that (see FIG. 8). That is, the coating apparatus 300 </ b> A includes a coating unit 40 that coats the pressure-sensitive adhesive composition and an irradiation unit 70 that radiates ultraviolet rays as energy rays, and further includes an unwinding unit 30 that feeds the release film 3 and the release film 5. It has the lamination | stacking part 50 and the winding part 90 which winds up the adhesive tape 1a in which the adhesive layer 4 was formed. The application unit 40 includes a pair of an upper surface roll 42 and a lower surface roll 44, and a dam 46 for supplying the adhesive composition 4 a is attached to the lower surface roll 44.

  A predetermined gap 48 is formed between the upper surface roll 42 and the lower surface roll 44, and the adhesive composition 4 a is applied onto the release film 3 when the release film 3 passes through the gap 48. Yes.

  The manufacturing process of the adhesive tape 1a of FIG. 1 will be described using the coating apparatus 300A.

  First, the release film 3 is drawn out to the application unit 40 from the web 34 of the release film 3 attached to the unwinding shaft 32 of the unwinding unit 30.

  The application unit 40 includes a pair of an upper surface roll 42 and a lower surface roll 44, and a dam 46 for supplying the adhesive composition 4 a is attached to the lower surface roll 44.

  A predetermined gap 48 is formed between the upper surface roll 42 and the lower surface roll 44, and the adhesive composition 4 a is applied onto the release film 3 when the release film 3 passes through the gap 48. Yes.

  Next, the release film 5 is pulled out from the release film web (not shown), placed on the pressure-sensitive adhesive composition 4 a, and the gap between the upper surface roll 52 and the lower surface roll 54 disposed in a pair of the laminated portions 50. When passing through 58, the release film 5 is laminated on the pressure-sensitive adhesive composition 4a.

  The release film 3 in which the pressure-sensitive adhesive composition 4a and the release film 5 are laminated is conveyed to an irradiation unit 70 that irradiates ultraviolet rays as energy rays. Here, the irradiation unit 70 is provided with a support roller 73 that supports movement of the release film in a metal irradiation chamber 71 and a light source lamp 72 that irradiates ultraviolet rays as energy rays. The pressure-sensitive adhesive composition 4a on the release film 3 conveyed into the irradiation chamber 71 is irradiated with ultraviolet rays from the light source lamp 72, thereby starting a polymerization reaction, and becomes a pressure-sensitive adhesive layer 4 after the polymerization reaction is completed. The intensity of the ultraviolet light of the light source lamp 72 is set so that the polymerization reaction is almost completed while the adhesive composition 4 a passes through the irradiation chamber 71.

  In the present invention, between the start of the polymerization reaction of the pressure-sensitive adhesive composition 4 a until the polymerization reaction is almost completed, the pressure-sensitive adhesive composition 4 a is placed between the pair of upper surface roll 82 and lower surface roll 84 of the thickness control roll unit 80. Pass through. Thereby, the swelling of the adhesive composition 4a can be pressed and eliminated to flatten the thickness. Here, the meaning that the polymerization reaction is almost completed means that the polymerization rate is 90% or more.

  As shown in FIG. 5, the thickness control roll unit 80 is usually disposed at one place inside the ultraviolet irradiation unit 70, but a plurality of thickness control roll units 80 may be disposed as long as the polymerization reaction is not completed. Not shown). Further, when it is necessary to design the roll diameter of the thickness control roll unit 80 to be large, the irradiation unit 70 is divided into the first half 70a and the second half 70b as in the manufacturing apparatus 300B of FIG. May be installed.

  Moreover, it is preferable to arrange | position the thickness control roll part 80 in the position where the polymerization rate of the adhesive composition 4a does not exceed 80% especially. Even if the thickness control roll 80 is passed at a position where the polymerization rate exceeds 80%, the thickness adjustment may not be sufficient depending on the type of the pressure-sensitive adhesive composition 4a.

  Here, in order to control the polymerization rate of the pressure-sensitive adhesive composition 4a, for example, the light source lamp provided in the irradiation unit 70 as in the manufacturing apparatus 300C of FIG. 7 is divided into the first half light source lamp 72a and the second half light source lamp 72b, When the illuminance of the light source lamp 72a is smaller than the illuminance of the light source lamp 72b, a range in which the polymerization rate of the pressure-sensitive adhesive composition 4a is 80% or less can be stably obtained. In this case, it is preferable that the thickness control roll unit 80 is disposed behind the light source lamp 72a as shown in FIG.

  On the other hand, the lower limit of the polymerization rate of the pressure-sensitive adhesive composition 4a when passing through the thickness control roll 80 is not limited, but if it is less than 20%, there is a possibility that swelling will appear after passing, so at least 20%. It is preferable to do.

  Here, as will be described later, the pressure-sensitive adhesive composition 4a of the present invention may be prepolymerized from the viewpoint of adjusting the liquid viscosity, but the polymerization rate of this prepolymerization is usually 10% or less, Even if it passes through the thickness control roll 80 at the stage of this polymerization rate, the effect of the present invention cannot be obtained.

  Next, the release film 3 on which the pressure-sensitive adhesive layer 4 having a thickness adjusted by the thickness control roll unit 80 is formed is unloaded from the irradiation unit 70 and wound up by the winding shaft 92 of the winding unit 90. 94. Next, the target adhesive tape 1a can be obtained by cutting the web 94 into a predetermined size.

  The production method and production apparatus of the present invention can be suitably applied to the production of a so-called non-supporting adhesive tape 1a as shown in FIG. 1, and also applied to the adhesive tape 1c of FIG. 3 and the single-sided adhesive tape 1d of FIG. Can be applied.

  In addition, when either peeling film 3 and 5 of the adhesive tape 1a of FIG. 1 is peeled and it bonds together through the base film 6, the adhesive tape 1b shown in FIG. 2 can also be obtained.

  Hereinafter, the constituent material of the adhesive tape applicable to the manufacturing method of this invention is demonstrated easily.

  The release films 3 and 5 are used for the purpose of protecting the adhesive surface of the adhesive layer 4. Further, the release film 3 has a function of supporting the pressure-sensitive adhesive composition 4a in the production process, and the release film 5 has a function of preventing the monomer from volatilizing when irradiated with ultraviolet rays as energy rays.

  As the base material of the release films 3 and 5, transparent plastic films such as polyester, polyethylene, polypropylene, and polycarbonate, and papers that transmit ultraviolet rays are generally used. A thin layer of a silicone compound or a fluorine compound is formed on these base materials. By forming, peelability is imparted.

  The thickness of the release films 3 and 5 varies depending on the purpose, but is usually 100 to 500 μm.

  The pressure-sensitive adhesive layer 4 contains an acrylic monomer (A) as a main component, and a photopolymerization initiator (B) and an additive (C) are added.

  As the acrylic monomer, an acrylic acid ester (A1) of an alkyl alcohol having 4 to 14 carbon atoms and acrylic acid and acrylic acid ester (A2) copolymerizable with the acrylic acid ester can be used.

  Specific examples of the acrylic ester (A1) include butyl acrylate, isoamyl acrylate, 2-ethylhexyl acrylate, nonyl acrylate, isononyl acrylate, isooctyl acrylate, lauryl acrylate, decyl acrylate, and the like.

  Specific examples of acrylic acid and acrylic acid ester (A2) are acrylic acid, methacrylic acid, ethyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, tetrafurfryl acrylate, isobornyl acrylate, ethoxyethyl acrylate. Butoxyethyl acrylate, phenoxyethyl acrylate, phenyl acrylate, cyclohexyl acrylate, and the like can be used.

  As the photopolymerization initiator (B), an acetophenone-based or benzophenone-based initiator can be preferably used. Specifically, 4-phenoxydicycloacetophenone, 4-t-butyl-dichloroacetophenone, diphenoxyacetophenone, 2 -Hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, benzoin, benzoin methyl ether, benzoin isobutyl ether, benzyl methyl ketal and mixtures thereof.

  The additive (C) is, for example, a non-halogen flame retardant such as melamine cyanurate added for the purpose of increasing flame retardancy, the viscosity of the nonwoven fabric or pressure-sensitive adhesive composition added for the purpose of increasing the cohesive strength of the pressure-sensitive adhesive layer. There are silica, glass beads, microballoons and the like added for the purpose of adjustment.

  By the way, the pressure-sensitive adhesive composition obtained by mixing the above (A), (B) and (C) may have a low liquid viscosity of 2 to 20 cps. Therefore, before supplying the pressure-sensitive adhesive composition to the coating apparatus, it is preferable to adjust the liquid viscosity to 1000 to 3000 cps by irradiating ultraviolet rays in advance and conducting a prepolymerization reaction.

  Moreover, liquid viscosity can be adjusted to said range also by adding a polymer with good compatibility, for example, rubber | gum, such as an acrylic rubber and a styrene butadiene, to an adhesive composition irrespective of prepolymerization reaction.

  The thickness of the pressure-sensitive adhesive layer 4 is not particularly limited, but is usually 50 to 800 μm.

  Hereinafter, the present invention will be specifically described with reference to examples.

Example 1
(Creation of adhesive composition)
To 100 g of a mixed monomer solution consisting of 90 g of 2-ethylhexyl acrylate and 10 g of acrylic acid, 3 g of acrylic rubber (Toacron PS220, manufactured by Toa Paint Co., Ltd.) is stirred and mixed for 48 hours in a vessel equipped with a stirrer, and the desired pressure-sensitive adhesive composition ( 1) was obtained. The viscosity of this composition was 750 cps.

(Creation of adhesive tape)
While putting the above-mentioned pressure-sensitive adhesive composition into the dam 46 of the manufacturing apparatus 300A of FIG. The pressure-sensitive adhesive composition (1) was applied to a thickness of 700 μm.

  Next, the release film 5 (transparent polyester film having a thickness of 50 μm and treated with one side silicone) is pulled out to the laminated portion 50 and placed on the pressure-sensitive adhesive composition (1), passed through the gap 58, and the pressure-sensitive adhesive composition ( 1) and release film 5 were laminated.

Next, in the irradiation part 70 which irradiates ultraviolet rays as energy rays, the pressure-sensitive adhesive composition (1) was irradiated with ultraviolet rays to start a polymerization reaction. At this time, the illuminance of the light source lamp 72 that irradiates ultraviolet rays is 352 nm in wavelength and 0.44 mW / cm ² .

  Next, the thickness control roll part 80 was arrange | positioned in the position where the polymerization rate of an adhesive composition (1) will be 60%, and the thickness 86 was adjusted by letting the clearance gap 86 pass.

  Next, after confirming that the polymerization rate of the pressure-sensitive adhesive composition (1) that passed through the irradiation part 70 that irradiates ultraviolet rays as energy rays became 90% or more to become the pressure-sensitive adhesive layer 4, the winding of the winding part 90 was performed. It was wound around a take-off shaft 92 to obtain a web 94 of an adhesive tape. And this web 94 was cut | judged in width 1 inch, and the target adhesive tape 1a was obtained.

(Evaluation results)
The thickness of the pressure-sensitive adhesive layer 4 of the pressure-sensitive adhesive tape 1a was measured, and the presence or absence of swelling of the pressure-sensitive adhesive layer 4 was further visually observed. As a result, the thickness of the pressure-sensitive adhesive layer 4 was about 710 μm, and swelling due to ultraviolet irradiation was not observed.

Example 2
(Creation of adhesive composition)
2-Hydroxy-2-methyl-1-phenylpropan-1-one (Daroquia 1173, Merck Ltd.) was added as a photopolymerization initiator to a mixed monomer solution 100 g consisting of 90 g of 2-ethylhexyl acrylate and 10 g of acrylic acid. While stirring in a container, the target pressure-sensitive adhesive composition (2) was obtained by irradiating ultraviolet rays with an ultraviolet irradiation device in a nitrogen atmosphere. The viscosity of this composition was 700 cps and the polymerization rate was about 5%.

(Creation of adhesive tape)
An adhesive tape 1a was produced from this adhesive composition (2) in the same manner as in Example 1 using the manufacturing apparatus 300C shown in FIG. Here, the thickness control roll unit 80 is disposed between the light source lamp 72a and the light source lamp 72b.

The light source lamp 72a in the first half of the irradiation unit 70 has a wavelength of 352 nm and 0.44 mW / cm ² , and the light source lamp 72b in the second half has a wavelength of 365 nm and an illuminance intensity of 35.5 mW / cm ² . The illuminance was set lower than the latter half.

  Further, the polymerization rate of the pressure-sensitive adhesive composition 4a when passing through the light source lamp 72a in the first half was 75%.

(Evaluation results)
Said adhesive tape 1a was evaluated by the same method as Example 1. As a result, the thickness of the pressure-sensitive adhesive layer 4 of the pressure-sensitive adhesive tape 1a was about 710 μm, and no swelling due to ultraviolet irradiation was observed.

Comparative Example 1
An adhesive tape 1a was produced in the same manner as in Example 1 except that the pressure-sensitive adhesive composition (2) of Example 2 was used and the conventional production apparatus 100 of FIG. 8 was used.

(Evaluation results)
In the pressure-sensitive adhesive tape 1a produced by the above-described method, the pressure-sensitive adhesive layer 4 is observed to swell when irradiated with ultraviolet rays, and the thickness of the pressure-sensitive adhesive layer 4 (target thickness = 700 μm) exceeds 750 μm. Was measured.

  ADVANTAGE OF THE INVENTION According to this invention, the adhesive tape which has an adhesive layer without a swelling and uniform thickness can be obtained.

It is sectional drawing of the adhesive tape obtained by the manufacturing method of this invention. It is sectional drawing of the adhesive tape obtained by the manufacturing method of this invention. It is sectional drawing of the adhesive tape obtained by the manufacturing method of this invention. It is sectional drawing of the adhesive tape obtained by the manufacturing method of this invention. It is the schematic of the manufacturing apparatus of this invention. It is the partial schematic of the manufacturing apparatus of this invention. It is the partial schematic of the manufacturing apparatus of this invention. It is the schematic of the conventional adhesive tape manufacturing apparatus. It is the partial schematic of the conventional adhesive tape manufacturing apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 30 ... Unwinding part, 40 ... Application | coating part, 50 ... Laminating part, 70 ... Irradiation part, 80 ... Thickness control roll part, 90 ... Winding part

Claims (3)

An adhesive composition is applied on a tape-like substrate, a release film is further laminated on the adhesive composition, and energy rays are applied to the adhesive composition sandwiched between the tape-like substrate and the release film. In the method for producing a pressure-sensitive adhesive tape having a pressure-sensitive adhesive layer formed by performing a polymerization reaction by irradiating
After the irradiation of the energy ray is started to the pressure-sensitive adhesive composition sandwiched between the tape-shaped substrate and the release film, the pressure-sensitive adhesive composition is until the polymerization reaction of the pressure-sensitive adhesive composition is almost completed. When adjusting the thickness by the thickness control means, a pair of rolls having a predetermined gap is used as the thickness control means, and the thickness adjustment is performed by passing the adhesive composition between the pair of rolls. A featured manufacturing method.   The production method according to claim 1, wherein the polymerization rate of the pressure-sensitive adhesive composition when passing between the pair of rolls is 80% or less.   The production method according to claim 2, wherein the polymerization rate of the pressure-sensitive adhesive composition when passing between a pair of rolls is 20% or more.

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