JP3045884B2 - Manufacturing method of adhesive tape - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a pressure-sensitive adhesive tape, and more particularly, to a method for forming a pressure-sensitive adhesive layer on a transfer belt and transferring the pressure-sensitive adhesive layer onto a base material. The present invention relates to a method for producing an adhesive tape by a so-called belt coating method for producing a tape.

[0002]

2. Description of the Related Art Many types of substrates are known as substrates for supporting an adhesive layer of an adhesive tape, such as kraft paper, Japanese paper and crepe paper, cloth, OPP (stretched polypropylene), Composite base materials and the like in which polyethylene is laminated on flat yarn such as rigid PVC and polyethylene are known.

[0003] For example, in the case of a pressure-sensitive adhesive tape based on paper, a method of directly applying a solvent-type pressure-sensitive adhesive directly to the paper substrate is generally used. As a result, it is necessary to apply more than the necessary amount, which increases the cost. Also, in the case of an adhesive tape based on kraft paper,
A method of applying an adhesive on the release surface has also been proposed,
When a solvent-based pressure-sensitive adhesive is applied, the peeled surface is undesirably attacked by the solvent. Use of release paper or the like also causes a problem that the cost is increased.

In Japanese Patent Publication No. 39-16796,
A so-called belt coating method has been proposed in which an adhesive is applied to a transfer belt and dried, and then the adhesive layer on the transfer belt is transferred onto a substrate to produce an adhesive tape.

In recent years, an adhesive tape using a base material having a polyethylene laminate layer provided on one side of a woven fabric made of polyethylene flat yarn has been widely used in recent years.
Since the polyethylene flat yarn base material is made of a thermoplastic resin, the base material undergoes remarkable thermal deterioration in a drying step after the application of the adhesive, resulting in a decrease in strength when processed as an adhesive tape. For this reason, in the same manner as the above-mentioned adhesive tape using paper as a base material, a method of applying a pressure-sensitive adhesive on a transfer belt to form an adhesive layer, and then transferring this onto a base material by a belt coating method has been proposed. ing.

[0006]

However, in the case of a pressure-sensitive adhesive tape made of paper as a base material, non-uniform portions exist in the paper base material, for example, slime of kraft paper or foreign matter portions called eyeballs. In addition, due to the presence of such a portion, a layer crack occurs during transfer by a belt coating method, and sometimes a problem occurs in a manufacturing process, such as cutting.

Further, in the case of an adhesive tape using a polyethylene flat yarn base material, there is a problem that the transfer of the adhesive layer from the transfer belt is not performed smoothly because the surface of the base material has few irregularities. This is because the cohesive force of the pressure-sensitive adhesive layer immediately after the drying step on the transfer belt is low.
For this reason, in the case of a pressure-sensitive adhesive tape of a polyethylene flat yarn substrate, it is necessary to apply a primer to the surface of the substrate or to improve the transferability to the substrate by corona discharge treatment.

[0008] An object of the present invention is to solve the conventional problems as described above, to prevent the occurrence of layer cracking and cutting when using paper as a base material, and to reduce the problem when using polyethylene flat yarn as a base material. It is an object of the present invention to provide a method for producing a pressure-sensitive adhesive tape which can favorably transfer a pressure-sensitive adhesive layer from a transfer belt without applying an undercoating agent to a substrate or performing corona discharge treatment.

[0009]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned conventional problems. As a result, when transferring the pressure-sensitive adhesive layer, the temperature of the surface of the pressure-sensitive adhesive layer was compared with the temperature of the surface of the transfer belt. By lowering the temperature by 10 ° C. or more, the cohesive force of the pressure-sensitive adhesive on the surface of the pressure-sensitive adhesive layer was increased, and it was found that the transferability from the transfer belt to the base material was improved, and the present invention was completed. That is, the present invention is a method for producing a pressure-sensitive adhesive tape by applying a pressure-sensitive adhesive layer on a transfer belt and drying, and then transferring the pressure-sensitive adhesive layer on the transfer belt to a substrate, and transferring the pressure-sensitive adhesive layer. In this case, the temperature of the surface of the pressure-sensitive adhesive layer is lower than the temperature of the surface of the transfer belt by 10 ° C. or more.

In the present invention, when transferring the pressure-sensitive adhesive layer, the temperature of the surface of the pressure-sensitive adhesive layer is set at a value lower than the temperature of the surface of the transfer belt by one.
The temperature is lowered by 0 ° C. or more, more preferably by 20 ° C. or more.
By setting the temperature of the pressure-sensitive adhesive layer surface lower than the temperature of the transfer belt surface in this manner, the cohesive force of the pressure-sensitive adhesive on the pressure-sensitive adhesive layer surface can be increased, and the transferability of the pressure-sensitive adhesive layer from the transfer belt to the substrate can be improved. Can be improved.

In the present invention, the base material of the pressure-sensitive adhesive tape is not particularly limited, and those conventionally used as the base material of the pressure-sensitive adhesive tape can be used. Kraft paper, Japanese paper (synthetic fiber such as vinylon, etc.) can be used. Including)
, Crepe paper, etc., and a composite support base material in which polyethylene is laminated on polyethylene and polypropylene flat yarn, cloth, OPP, rigid P
A substrate such as VC can be used.

As the transfer belt used in the present invention, a metal belt of stainless steel or the like, a cloth belt coated with Teflon, or the like can be used, and after applying and drying an adhesive, the adhesive layer can be transferred onto a substrate. Any such transfer belt can be used.

A release agent layer can be provided on the surface of the substrate opposite to the surface on which the adhesive layer is provided, similarly to a conventional adhesive tape. A laminate layer may be provided on the material, and a release agent layer may be formed on the laminate layer. As such a release agent, a silicon-based or organic release agent or the like can be used.

Although the base polymer of the pressure-sensitive adhesive forming the pressure-sensitive adhesive layer is not particularly limited, for example, a general-purpose rubber-based, acrylic-based, or hot-melt-based pressure-sensitive adhesive can be appropriately used. These include natural rubber,
Isoprene rubber, styrene-butadiene copolymer rubber (SBR), butadiene rubber, isobutylene-isoprene rubber, acrylic rubber, acrylonitrile-butadiene copolymer rubber, styrene-isoprene block copolymer rubber (SIS), styrene-butadiene. Examples include block copolymer rubber (SBS), chloroprene rubber, butyl rubber, recycled rubber, and the like, and mixtures thereof.

Further, in addition to the base polymer, a tackifier resin, a filler, a softener, an antioxidant, etc.
What is added to the adhesive layer of a normal adhesive tape can be used.

In the present invention, the method of lowering the temperature of the surface of the pressure-sensitive adhesive layer lower than the temperature of the surface of the transfer belt when transferring the pressure-sensitive adhesive layer is not particularly limited.
For example, before the transfer of the pressure-sensitive adhesive layer, a method of cooling the pressure-sensitive adhesive layer from the surface side by blowing air or heating the pressure-sensitive adhesive layer from the back side of the transfer belt to make the temperature of the transfer belt surface higher than the pressure-sensitive adhesive layer surface is adopted. can do.

[0017]

According to the present invention, when the pressure-sensitive adhesive layer is transferred, the temperature of the surface of the pressure-sensitive adhesive layer is lower than the temperature of the surface of the transfer belt by 10 ° C. or more. For this reason, the cohesive force of the pressure-sensitive adhesive on the surface of the pressure-sensitive adhesive layer is increased, and the transferability of the pressure-sensitive adhesive layer from the transfer roll to the substrate is improved. Therefore, for example, when paper is used as the base material, the pressure-sensitive adhesive layer can be smoothly and stably transferred to the base material without causing layer cracking or cutting which has been a problem in the past. When a polyethylene flat yarn base material is used as the base material, the transfer of the pressure-sensitive adhesive layer from the transfer belt to the base material is improved without applying a primer to the base material or performing corona discharge treatment. It can be carried out.

[0018]

FIG. 1 is a schematic diagram showing an example of an apparatus for carrying out the manufacturing method of the present invention. As shown in FIG. 1, a transfer belt 1 made of a stainless steel endless belt is hung on a drum 2. The transfer belt 1 is formed by a drum (not shown) provided in a drying furnace 3 and a drum 2. We are traveling back and forth. An adhesive application device 4 for applying an adhesive onto the transfer belt 1 is provided on the transfer belt 1 toward the drying furnace 3. The adhesive is applied onto the transfer belt 1, and the adhesive is applied to the transfer belt 1. The agent layer 9 is formed. The pressure-sensitive adhesive layer 9 passes through the drying furnace 3 to remove the contained solvent and the like and is dried. The pressure-sensitive adhesive layer 9 coming out of the drying furnace 3 is sent to the press roll 8 in contact with the drum 2 via the transfer belt 1 and the base material 7. At the contact point between the press roll 8 and the drum 2, the pressure-sensitive adhesive layer 9 on the transfer belt 1
Transferred to the side.

FIG. 2 is an enlarged view showing this transfer state. As shown in FIG. 2, the pressure-sensitive adhesive layer 9 is peeled off from the transfer belt 1 and is transferred onto the base material 7. In this way, the pressure-sensitive adhesive layer 9 is formed on the base material 7 to produce a pressure-sensitive adhesive tape.

As shown in FIG. 1, before the transfer of the pressure-sensitive adhesive layer 9, the surface of the pressure-sensitive adhesive layer 9 is cooled by the pressure-sensitive adhesive layer cooling device 5. Such cooling lowers the temperature of the surface of the pressure-sensitive adhesive layer 9 by 10 ° C. or more than the temperature of the surface of the transfer belt 1.

FIG. 3 is a side view showing the pressure-sensitive adhesive layer 9 provided on the transfer belt 1. The temperature of the surface a of the pressure-sensitive adhesive layer 9 shown in FIG. Also 10
The surface of the pressure-sensitive adhesive layer 9 is cooled such that the temperature becomes lower than or equal to ° C.

Instead of the adhesive cooling device 5 shown in FIG.
Such a temperature difference may be provided using the belt heating device 6 shown in FIG. That is, the belt heating device 6 is provided on the back side of the transfer belt 1 and heats the transfer belt 1 from the back side so that the temperature of the surface of the transfer belt 1 becomes higher than the temperature of the surface of the adhesive layer 9. doing. In the case of this embodiment, the transfer belt 1 coming out of the drying furnace 3
By keeping the temperature of the
The temperature difference from the surface temperature of the pressure-sensitive adhesive layer 9 is formed.

It should be noted that either the adhesive cooling device 5 or the belt heating device 6 shown in FIG. 1 may be provided with only one of them, or both may be provided together and used together. Next, an example of producing an adhesive tape using paper as a base material using the apparatus shown in FIG. 1 will be described.

Example 1 A polyethylene laminate layer was formed on one surface of kraft paper, a silicon release layer was formed on the polyethylene laminate layer, and a kraft paper base material serving as a base material of the adhesive tape was prepared. Next, a natural rubber-based solvent-based adhesive is applied to a stainless steel belt as a transfer belt and dried, and then a 10 ° C cold air is applied to the surface of the adhesive layer by an adhesive cooling device, and immediately thereafter. This pressure-sensitive adhesive layer was transferred to the surface of the kraft paper substrate opposite to the release layer. After transferring the adhesive layer, the kraft paper adhesive tape was wound up. The temperature of the surface of the transfer belt during the transfer was 95 ° C., and the temperature of the surface of the pressure-sensitive adhesive layer was 78 ° C.

FIG. 4 is a sectional view showing the laminated structure of the kraft paper adhesive tape thus obtained. As shown in FIG. 4, a release agent layer 13 is provided on one surface of a kraft paper base material 11 via a polyethylene laminate layer 12, and an adhesive layer 9 is provided on the other surface.

When a kraft paper pressure-sensitive adhesive tape was manufactured continuously for several hours in this manner, a kraft paper pressure-sensitive adhesive tape could be stably manufactured without causing layer cracking or cutting, which was a conventional problem.

Comparative Example 1 In the above-mentioned Example 1, the pressure-sensitive adhesive layer was transferred onto the substrate without blowing the cool air from the pressure-sensitive adhesive cooling device onto the surface of the pressure-sensitive adhesive layer. At this time, the surface temperature of the transfer belt is 9
The temperature was 7 ° C, and the temperature of the pressure-sensitive adhesive layer surface was 93 ° C. When continuous operation was attempted, layer cracking occurred immediately after starting operation, leading to cutting, and the operation had to be stopped. Next, an example using a polyethylene flat yarn base material as a base material will be described.

Example 2 On one surface of a woven fabric of polyethylene denier yarn having 90 denier as warp and 320 denier as weft,
A polyethylene laminate layer of 25 to 50 μm was formed at a molding temperature of 300 ° C. On this laminate layer side, a silicone release agent was applied by Meyer bar coating to provide a release agent layer, thereby preparing a polyethylene flat yarn base material.

Using a device shown in FIG. 1, a solvent-based pressure-sensitive adhesive based on natural rubber is applied to a stainless steel belt as a transfer belt and dried. The pressure-sensitive adhesive layer was transferred to the opposite surface. Immediately before the transfer, a cold air of 15 ° C. was applied to the pressure-sensitive adhesive layer from the pressure-sensitive adhesive cooling device to cool the temperature of the pressure-sensitive adhesive layer surface. The transfer belt surface temperature during transfer is 93 ° C
And the temperature of the surface of the pressure-sensitive adhesive layer was 80 ° C. The pressure-sensitive adhesive layer was transferred from the transfer belt to the substrate to prepare a pressure-sensitive adhesive tape, which was wound. The transfer of the pressure-sensitive adhesive layer from the transfer belt to the substrate was successfully performed.

Comparative Example 2 An attempt was made to produce a pressure-sensitive adhesive tape in the same manner as in Example 1, except that the surface of the pressure-sensitive adhesive layer was not cooled by a pressure-sensitive adhesive cooling device before the transfer. However,
In this case, transfer of the adhesive was impossible.

FIG. 5 shows a cross section of the pressure-sensitive adhesive tape obtained in Example 2, and shows polyethylene flat yarn 2
On one side, a polyethylene laminate layer 22 is provided, and a release agent layer 23 is provided on the polyethylene laminate layer 22. An adhesive layer 9 is formed on the other surface of the polyethylene flat yarn 21.

On the other hand, in Comparative Example 2, transfer of the pressure-sensitive adhesive layer was impossible as described above. In the case where the pressure-sensitive adhesive layer is not cooled before the transfer as in Comparative Example 2, as shown in FIG.
4 and the pressure-sensitive adhesive layer 35 needs to be transferred onto the undercoat layer 34. In FIG. 6, 32 indicates a polyethylene laminate layer, and 33 indicates a release agent layer.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an example of an apparatus for explaining a manufacturing method according to the present invention.

FIG. 2 is an enlarged view showing a state where an adhesive layer is transferred from a transfer belt to a base material.

FIG. 3 is an enlarged view showing an adhesive layer on a transfer belt.

FIG. 4 is a sectional view showing the pressure-sensitive adhesive tape obtained in Example 1.

FIG. 5 is a sectional view showing the pressure-sensitive adhesive tape obtained in Example 2.

FIG. 6 is a sectional view showing a comparative pressure-sensitive adhesive tape in which an undercoat layer is formed on a base material and the pressure-sensitive adhesive layer is transferred.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Transfer belt 2 ... Drum 3 ... Drying furnace 4 ... Adhesive coating device 5 ... Adhesive cooling device 6 ... Belt heating device 7 ... Base material 8 ... Press roll 9 ... Adhesive layer

Claims (1)

(57) [Claims] 1. A method of manufacturing a pressure-sensitive adhesive tape by applying a pressure-sensitive adhesive on a transfer belt and drying the pressure-sensitive adhesive layer, and then transferring the pressure-sensitive adhesive layer on the transfer belt to a base material. A method for producing a pressure-sensitive adhesive tape, wherein the temperature of the surface of the pressure-sensitive adhesive layer is lower than the temperature of the surface of the transfer belt by at least 10 ° C.