JP7377534B2 - Adhesive tape for preventing three-sided adhesion of sealants - Google Patents

Description

Application of Article 30, Paragraph 2 of the Patent Act On August 2, 2020, we transferred a prototype of an adhesive tape for preventing three-sided adhesion of sealants to a customer.

The present invention relates to an adhesive tape for preventing three-sided adhesion that occurs when filled with a sealant.

For example, a plurality of ceramic siding boards are used as exterior wall materials for houses. Furthermore, for example, a plurality of exterior wall panels are used as exterior wall materials for high-rise buildings. When the above-mentioned exterior wall materials are constructed, joints are formed between a plurality of exterior wall materials. Such joints are filled with a sealant for waterproofing purposes.

The sealant filled in the joint area undergoes movement due to shrinkage due to temperature differences in building members such as exterior wall materials, shaking of the building, or distortion. The joint where the movement works is called the working joint.

As described in paragraph 0003 of Patent Document 1 shown below, the adhesion of the filled sealant to the bottom part of the joint formed between the side surface of the outer wall and the wall is called three-sided adhesion. .

When the working joint is bonded on three sides, the filled sealant may not be able to follow the movement as described above. As a result, the sealant may peel off from the building member, rupture, or crack, and the sealant may no longer perform its original function.

Patent Document 1 describes that an adhesive tape is attached to a surface of a joint formed between two exterior wall boards. The adhesive tape has a plastic sheet surface. It is said that the surface of the plastic sheet is roughened by embossing or other processing. According to such an adhesive tape, the adhesiveness between the caulking material and the adhesive tape is reduced, and the caulking material is said to no longer adhere firmly to the back surface of the adhesive tape.

Patent Document 2 also describes a film in which the surface of a plastic sheet is similarly roughened. Patent Document 2 describes that this film is attached to an aluminum material.

Japanese Patent Application Publication No. 2002-188064 JP2002-206291A

In order to prevent the above-mentioned three-sided adhesion, adhesive tapes based on polyolefin films have conventionally been used. Such adhesive tapes have a soft base material, a high elongation rate, and are easily distorted when force is applied. For this reason, for example, when attaching adhesive tape to the bottom of a joint, the construction work was difficult. Particularly when the width of the joint is narrow, it becomes more difficult to properly apply adhesive tape to the bottom of the joint. Further, the above-mentioned adhesive tape tends to stretch when force is applied due to the high elongation rate of the base material, and tends to restore its original shape when the force is removed. Because the above-mentioned adhesive tape has such properties, the adhesive tape sometimes peels off after being attached to the bottom of the joint.

Further, as a known adhesive tape, there is an adhesive tape that is made of kraft paper or Japanese paper and coated with a silicone treatment agent on the back side. Before filling the joint with a sealant, a primer is sometimes applied to the joint so that the sealant will strongly adhere to the building components via the primer. In the case of adhesive tapes treated with the above-mentioned silicone-based treatment agent, the surface treated with the silicone-based treatment agent and the primer sometimes adhere firmly, resulting in three-sided adhesion.

In addition, when the back surface of the tape or film is roughened as in Patent Documents 1 or 2, the primer of the sealant may enter the recesses of the roughened plastic surface on the back surface of the tape or film. In some cases, the sealant or primer was firmly attached to the bottom of the joint. Particularly when the viscosity of the primer is low, this problem is likely to occur, probably because the primer material tends to penetrate into the recesses of the roughened plastic surface.

An object of the present invention is to provide a three-sided adhesive tape for preventing adhesion, in which a sealant or primer is difficult to adhere to the back surface of the adhesive tape, and the adhesive tape has less elongation and distortion during installation.

An adhesive tape having a base material made of Japanese paper or kraft paper, a synthetic resin layer disposed on one side of the base material, and an adhesive layer disposed on the other side of the base material, The above-mentioned problems are solved by an adhesive tape for preventing three-sided adhesion of a sealant, in which the critical surface tension of the resin layer is 30 mN/m or less, and the tensile elongation of the adhesive tape according to JIS Z 0237 is 8% or less.

In the above three-sided adhesive tape for preventing adhesion, the thickness of the base material is preferably 25 to 200 μm. Further, in the above three-sided adhesive tape for preventing adhesion, the thickness of the synthetic resin layer is preferably 2 to 50 μm. Further, in the above three-sided adhesive tape for preventing adhesion, the adhesive layer contains at least one of a rubber adhesive, an acrylic adhesive, and a urethane adhesive, and the thickness of the adhesive layer is preferably 20 to 200% of the thickness of the base material.

According to the present invention, it is possible to provide a three-sided adhesive tape for preventing adhesion, in which a sealant or an undercoat material is difficult to adhere to the back surface of the adhesive tape, and the adhesive tape has less elongation and distortion during installation.

FIG. 3 is a sectional view showing a first usage example of the adhesive tape for preventing three-sided adhesion. FIG. 7 is a cross-sectional view showing a second usage example of the adhesive tape for preventing three-sided adhesion. FIG. 7 is a cross-sectional view showing a third usage example of the adhesive tape for preventing three-sided adhesion. FIG. 7 is a cross-sectional view showing a fourth usage example of the adhesive tape for preventing three-sided adhesion. FIG. 2 is a cross-sectional view of an example of a three-sided adhesive tape for preventing adhesion.

Hereinafter, preferred embodiments for carrying out the present invention will be described. The embodiments shown below are merely examples, and the technical scope of the present invention is not limited to the embodiments shown below.

The present invention provides a sealing material having a base material made of Japanese paper or kraft paper, a synthetic resin layer placed on one side of the base material, and an adhesive layer placed on the other side of the base material. This is an adhesive tape for preventing three-sided adhesion (hereinafter sometimes simply referred to as adhesive tape).

The above adhesive tape is used to prevent three-sided adhesion between the sealant filled into the joint formed between multiple exterior wall materials, the bottom of the joint, and the side surface of the exterior wall material. . Examples of how adhesive tapes are used will be described with reference to FIGS. 1 to 4.

In the example of FIG. 1, one outer wall material 11 and the other outer wall material 12 are connected by a flat connecting member 13. There is a gap between the outer wall material 11 and the outer wall material 12, forming a joint. The portion of the connecting member 13 exposed to the joint forms the bottom portion of the joint. The joints are filled with a sealant 21. In the example of FIG. 1, a primer 14 is applied for the purpose of improving the adhesive force between the side wall portion 111 of the outer wall material 11 and the side wall portion 112 of the outer wall material 12 and the sealing material 21. When applying the primer 14 to the joints, the primer is applied or sprayed onto the joints. The bottom part of the joint is not masked to improve workability. For this reason, the primer 14 is also applied to the bottom of the joint.

The three-sided adhesive tape 3 is applied to the bottom of the joint before applying the primer 14 and sealant 21. Therefore, the joint has a structure in which the connecting member 13, the adhesive tape 3, the primer 14, and the filler 21 are laminated in the order listed from bottom to top. A primer 14 is laminated on the side wall portion of the outer wall material.

Figure 2 shows another joint structure. In the example of FIG. 2, a side wall portion 111b of one of the outer walls 11b is provided with a convex portion 112 having a smaller thickness than the central portion of the outer wall material. Similarly, the side wall portion 112b of the other outer wall 12b is provided with a convex portion 122 having a smaller thickness than the central portion of the outer wall material. The convex portion 112 and the convex portion 122 have a structure in which they abut against each other, and the abutted portion forms the bottom portion of the joint. Adhesive tape 3 is attached to the bottom part. This example is similar to the example shown in FIG. 1 in that a primer 14 is applied on top of the adhesive tape 3, and then a sealant 21 is applied.

Figure 3 shows another joint structure. The example of FIG. 3 differs from the structure of FIG. 1 in that one exterior wall material 11 and the other exterior wall material 12 are connected using a plate-shaped connecting member 13c having a protrusion that is fitted into the joint. are different. The bottom of the joint is raised by the protrusion of the connecting member 13c, and the depth is smaller than that of the structure shown in FIG. The adhesive tape 3 is attached to the protrusion of the connecting member forming the bottom part of the joint.

Figure 4 shows another joint structure. The example shown in FIG. 4 differs from the structure shown in FIG. 1 in that the primer 14 is not used and the joints formed by the outer wall material and the connecting member are filled with a sealant. The adhesive tape 3 is in direct contact with the sealant without using a primer.

As will be described later, the adhesive tape has excellent releasability with respect to a sealant or a primer, and the sealant or primer is difficult to adhere to one surface of the adhesive tape. For this reason, in the examples shown in FIGS. 1 to 4, it is difficult to form a strong bond between the adhesive tape 3 stuck to the bottom of the joint and the primer 14 or the sealant 21. On the other hand, since no adhesive tape is attached to the side wall parts 111 and 112 of the outer wall material, the sealing material 21 is bonded on two sides with the side wall parts 111 and 112 of the outer wall material.

For example, assume that stress is applied in the lateral direction to the other outer wall 12, 12b, as indicated by the arrows in FIGS. 1 to 4. Since the primer 14 or the sealing material 21 is not firmly adhered to the adhesive tape 3 attached to the connecting member etc., the primer 14 or the sealing material 21 does not adhere to the connecting member 13, the connecting member 13c, the protrusion 112, or It can expand and contract without being restricted by the convex portion 122 and follow the movement of the outer wall 12. This prevents the sealing material 21 from tearing, peeling, or cracking.

FIG. 5 shows an example of the structure of the adhesive tape 3. The adhesive tape 3 includes a base material 31 cut into a strip shape, a synthetic resin layer 32 disposed on one surface of the base material 31, and an adhesive layer 33 disposed on the other surface. The adhesive tape 3 may be wound around a core material to form a tape roll, or a strip of adhesive tape may be attached to a release paper. The critical surface tension of the synthetic resin layer is 30 mN/m or less, and the tensile elongation rate of the adhesive tape according to JIS Z 0237 is 8% or less. Note that the lower limit of the tensile elongation rate is not particularly limited, but it can be set to a value larger than 0 mN/m, or it can also be set to 2 mN/m or more. Further, the lower limit value of the critical surface tension is not particularly limited, but can be set to a value larger than 0 mN/m or larger than 18 mN/m, for example.

The base material is made of Japanese paper or kraft paper. The thickness of the base material is not particularly limited, but can be, for example, 20 to 350 μm. The thickness of the tape base material may be 20 to 200 μm. A synthetic resin layer is provided on the base material. Although the method of constructing the synthetic resin layer is not particularly limited, it can be constructed, for example, by the following method. The synthetic resin layer may be formed, for example, by an extrusion lamination method in which a molten synthetic resin is extruded into a sheet, laminated onto a base material, and the molten synthetic resin is solidified. Alternatively, it may be formed by a melt lamination method in which a molten synthetic resin is applied to a base material. Alternatively, it may be formed by a dry lamination method in which a sheet-like synthetic resin is fixed to a base material with an adhesive or an adhesive.

The Japanese paper or kraft paper that constitutes the base material may be treated with an impregnating agent. Examples of impregnating agents include, but are not limited to, natural rubber; acrylic rubber, butyl rubber, butadiene rubber, isobutylene rubber, styrene-butadiene copolymer rubber, styrene-butadiene-styrene copolymer rubber, styrene-isoprene copolymer rubber, and styrene. - Isoprene-styrene copolymer rubber, acrylonitrile-butadiene copolymer rubber, acrylonitrile-butadiene-isoprene copolymer rubber, butadiene-(meth)acrylic acid copolymer rubber, butadiene-(meth)acrylic acid ester copolymer rubber, (meth) Acrylic acid grafted natural rubber, (meth)acrylic acid ester grafted natural rubber, styrene grafted natural rubber, acrylonitrile grafted natural rubber, synthetic isoprene rubber, ethylene-propylene copolymer rubber, ethylene-propylene-diene copolymer rubber, ethylene-vinyl acetate Copolymer rubber, ethylene-(meth)acrylic acid copolymer rubber, ethylene-(meth)acrylic acid ester copolymer rubber, ethylene-acrylonitrile copolymer rubber, polyether urethane rubber, polyester urethane rubber, silicone rubber, liquid isoprene rubber, Synthetic rubbers (synthetic elastomers) such as liquid butadiene, liquid styrene-butadiene copolymer rubber, liquid acrylonitrile-butadiene copolymer rubber, and liquid oxypropylene rubber; shellac; polyvinyl alcohol, polyvinyl butyral, polyvinyl acetate, polyvinyl chloride, Synthetic resins such as (meth)acrylic acid copolymers and (meth)acrylic ester copolymers; (meth)acrylic acid, (meth)acrylic esters, (meth)acrylonitrile, hydroxy(meth)acrylate, vinyl acetate, Examples include copolymer resins obtained by copolymerizing at least two or more monomers selected from the group consisting of vinyl chloride, styrene, and monomers having an N-alkylol group or an N-alkoxyalkyl group. The copolymer may be a random body, a block body, a graft body, or a modified body thereof. One type of impregnating agent may be used, or two or more types may be used in combination.

As the synthetic resin layer, for example, polymethylpentene can be suitably used as a main component.

The thickness of the synthetic resin layer is not particularly limited, but if the thickness of the synthetic resin layer is in the range of 2 to 50 μm, good manual tearability can be imparted to the adhesive tape. The thickness of the synthetic resin layer may be 5 to 30 μm.

As the adhesive layer, for example, at least one of rubber adhesives, acrylic adhesives, silicone adhesives, urethane adhesives, etc. can be used.

As the rubber adhesive, those conventionally used can be used. For example, natural rubber, butyl rubber, butadiene rubber, isobutylene rubber, styrene-butadiene copolymer rubber, styrene-butadiene-styrene copolymer rubber, styrene-isoprene copolymer rubber, styrene-isoprene-styrene copolymer rubber, acrylonitrile-butadiene copolymer rubber. Rubber, acrylonitrile-butadiene-isoprene copolymer rubber, methyl methacrylate grafted natural rubber, styrene grafted natural rubber, acrylonitrile grafted natural rubber, synthetic isoprene rubber, ethylene-propylene copolymer rubber, ethylene-propylene-diene copolymer rubber, ethylene- Vinyl acetate copolymer rubber, ethylene-acrylic acid ester copolymer rubber, ethylene-acrytonitrile copolymer rubber, butadiene-(meth)acrylic acid ester copolymer rubber, polyether urethane rubber, polyester urethane rubber, liquid isoprene rubber, liquid Examples include butadiene, liquid styrene-butadiene copolymer rubber, liquid acrylonitrile-butadiene copolymer rubber, and liquid oxypropylene rubber.

The acrylic adhesive is not particularly limited, but for example, the following acrylic polymers can be used. That is, (A) an acrylic acid alkyl ester whose alkyl group has 4 to 12 carbon atoms and/or a methacrylic acid alkyl ester whose alkyl group has 4 to 18 carbon atoms, and (B) an α,β-unsaturated carboxylic acid 0 obtained by polymerizing a monomer mixture containing 1 to 5% by mass, or a mixture of a monomer copolymerizable with the above component A in an amount not exceeding 40 parts by mass per 100 parts by mass of the monomer mixture. It is a polymer. Component A is preferably 85 to 98.9% by mass.

The adhesive may contain additives such as a tackifying resin or a plasticizer within a range that does not impair its effectiveness.

The tackifier resin is not particularly limited, but includes, for example, terpene resin, terpene phenol resin, phenol resin, aromatic hydrocarbon-modified terpene resin, rosin resin, modified rosin resin, aliphatic synthetic petroleum resin. , aromatic synthetic petroleum resin, alicyclic synthetic petroleum resin, coumaron-indene resin, xylene resin, styrene resin, and dicyclopentadiene resin. Among the above-mentioned tackifying resins, for those having unsaturated double bonds to which hydrogen can be added, compounds to which hydrogen can be added may be used.

The thickness of the adhesive layer is not particularly limited, but can be, for example, 20 to 200% of the thickness of the base material of the adhesive tape, or 20 to 250 μm. Adjusting the thickness of the adhesive layer makes it difficult for the adhesive to protrude from the sides of the adhesive tape, improves the ability of the adhesive tape to follow the adherend, and makes it difficult to leave adhesive residue when the adhesive tape is peeled off. be able to.

The adhesive strength of the adhesive tape is not particularly limited, but can be, for example, 1.0 N/10 mm or more. Further, the adhesive strength of the adhesive tape can be selected within the range of 1.0 N/10 mm to 5.0 N/10 mm, or 1.5 N/10 mm to 3.0 N/10 mm.

Adhesive strength is measured according to JIS Z0237, and specifically, a SUS304 steel plate with a thickness of 2 mm or more, a width of about 50 mm, and a length of about 125 mm as specified in JIS G 4305, with a mirror finish or polished with waterproof abrasive paper. A test piece with a width of 25 mm and a length of 250 mm was attached in an atmosphere of a temperature of 23 ± 2°C and a relative humidity of (50 ± 5)%, and the spring hardness specified in JIS K6253 was 80 ± 5 Hs. , using an automatic crimping device with a roller having a width of about 45 mm, a diameter including the rubber layer of about 95 mm, and a mass of 2,000 ± 50 g, covered with a rubber layer about 6 mm thick, at a speed of about 5 mm/s, 1 This is the load obtained by peeling off something that has been crimped back and forth at 180 degrees and at a speed of about 300 mm/s.

The adhesive layer may contain air bubbles. By including air bubbles, the flexibility of the adhesive layer is improved. Furthermore, since the surface layer of the adhesive layer is rough, the adhesive tape has low adhesion but sufficient tack, so-called a well-balanced adhesive tape with good adhesion and removability.

The method for containing bubbles is not particularly limited, but for example, a blowing agent such as an azo type, a sulfonyl hydrazide type, a nitroso type, an inorganic type, etc. that generates gas by causing thermal decomposition or a chemical reaction by itself is included. Method: A chemical method such as a method of containing thermally foamable or thermally expandable microcapsules; A method of directly containing bubbles generated by rapidly volatilizing a solvent or dispersion medium during drying; Before coating Examples include physical methods such as a method of mechanically forming bubbles by rapidly stirring a pressure-sensitive adhesive compounded liquid.

Although not essential, an undercoating agent layer may be provided between the base material and the adhesive layer. By providing an undercoat layer, the strength of the base material can be improved, the adhesive strength between the base material and the adhesive layer can be increased, and the adhesive can be prevented from being excessively absorbed by the base material. Can be done. The amount of the undercoat agent applied is not particularly limited, but can be in the range of 0.5 to 40 g/m ² or 2 to 20 g/m ² in terms of dry weight.

Examples of the undercoat agent include, but are not limited to, natural rubber, butyl rubber, butadiene rubber, isobutylene rubber, styrene-butadiene copolymer rubber, styrene-butadiene-styrene copolymer rubber, styrene-isoprene copolymer rubber, and styrene-isoprene. -Styrene copolymer rubber, acrylonitrile-butadiene copolymer rubber, acrylonitrile-butadiene-isoprene copolymer rubber, methyl methacrylate graft natural rubber, styrene graft natural rubber, acrylonitrile graft natural rubber, synthetic isoprene rubber, ethylene-propylene copolymer rubber, Ethylene-propylene-diene copolymer rubber, ethylene-vinyl acetate copolymer rubber, ethylene-acrylic acid ester copolymer rubber, ethylene-acrytonitrile copolymer rubber, butadiene-(meth)acrylic acid ester copolymer rubber, polyether urethane Elastomers such as rubber, polyester urethane rubber, liquid isoprene rubber, liquid butadiene, liquid styrene-butadiene copolymer rubber, liquid acrylonitrile-butadiene copolymer rubber, liquid oxypropylene rubber; shellac; polyvinyl alcohol, polyvinyl butyral, polyvinyl acetate , polyvinyl chloride, (meth)acrylic acid copolymers, (meth)acrylic acid ester copolymers, and other synthetic resins; (meth)acrylic acid, (meth)acrylic esters, (meth)acrylonitrile, hydroxy (meth) A copolymer resin obtained by copolymerizing at least two or more monomers selected from the group consisting of acrylate, vinyl acetate, styrene, monomers having an N-alkylol group or an N-alkoxyalkyl group; chlorobutyl rubber, bromobutyl rubber, chloroprene rubber , epichlorohydrin rubber, chlorinated polyethylene, chlorosulfonated polyethylene, carboxylated acrylonitrile-butadiene copolymer rubber, liquid chloroprene rubber, liquid carboxylated polyisoprene rubber, liquid carboxylated polybutadiene, liquid hydroxylated polyisoprene, liquid hydroxylated polybutadiene rubber, Examples include elastomers having highly reactive functional groups such as liquid aminated polybutadiene rubber.

The above-mentioned undercoat agents may be used alone or in combination of two or more. In addition, for compounds that have unsaturated double bonds that can add hydrogen to their molecules, compounds with hydrogen added to them may be used, or sulfur-containing vulcanizing agents, inorganic vulcanizing agents, resin vulcanizing agents, etc. In addition to various vulcanizing agents such as sulfurizing agents, crosslinking agents such as oximes, nitroso compounds, polyamines, polyethyleneimines, and organic peroxides may be used in combination for crosslinking. Even for molecules with highly reactive functional groups, crosslinking can be achieved by using various crosslinking agents that can react with the functional groups, such as metal compounds, amino compounds, epoxy compounds, isocyanate compounds, etc. Good too.

Hereinafter, the present invention will be described in more detail by giving examples. The examples shown below are merely illustrative, and the technical scope of the present invention is not limited to the examples shown below.

[Example 1]
(Base material for adhesive tape)
A 25 μm thick polymethylpentene film extrusion laminated on one side of base paper was used as a base material. The base paper has an elongation rate of 2.5% determined according to JIS Z 0237, and a thickness of 55 μm. The critical surface tension of a film of polymethylpentene is 24 mN/m.

The above critical surface tension was determined by the following method. That is, in an atmosphere of 23°C and 50% relative humidity, five or more types of test mixtures with known surface tensions according to JIS K 6768 were applied to the surface of a polymethylpentene film (test piece). The drops touched. The diameter of the droplet was approximately 2 mm. The contact angle (θ) was measured in the same atmosphere as above using a contact angle meter (CA-S Micro 2 model manufactured by Kyowa Interface Science Co., Ltd.). The measurement was performed on 10 test pieces, and the average value was determined. Then, cos θ was determined from the average value of the contact angle θ. The relationship between cos θ and contact angle θ of each test mixture was plotted on the graph, with the vertical axis of the graph representing cos θ and the horizontal axis representing the surface tension of the test mixture. Approximate straight lines were drawn using the least squares method for the plotted points. Then, the surface tension (horizontal axis) corresponding to the intersection of the straight line and cos θ=1 was read, and the value was taken as the critical surface tension (mN/m).

An adhesive prepared by the following method was applied to the other side of the base material on which the synthetic resin layer was laminated by the above method. After drying the adhesive, the adhesive tape was wound around a cylindrical core material to obtain a tape roll. The adhesive was used so that the thickness of the tape after drying was 110 μm.

(Preparation of adhesive)
3 parts by mass of a chelate crosslinking agent was added to 100 parts by mass of a solvent-type acrylic adhesive (acrylic acid ester copolymer) and used as an adhesive.

[Example 2]
A kraft paper with the same polymethylpentene film used in Example 1 extrusion laminated on one side was used as a base material. The kraft paper has an elongation rate of 2.3% determined according to JIS Z 0237, and a thickness of 65 μm.

The same adhesive used in Example 1 was applied to the other side of the base material on which the synthetic resin layer was laminated by the above method. After drying the adhesive, the adhesive tape was wound around a cylindrical core material to obtain a tape roll. The adhesive was used so that the thickness of the tape after drying was 120 μm.

[Example 3]
An adhesive tape was produced in the same manner as in Example 1, except that the adhesive was applied so that the thickness of the tape after drying was 280 μm.

[Example 4]
An adhesive tape was produced in the same manner as in Example 1, except that the thickness of the polymethylpentene film was 55 μm, and the adhesive was applied so that the thickness of the tape after drying was 140 μm. .

[Example 5]
The tape base material was changed to kraft paper with an elongation rate of 2.5% (tensile elongation at break according to JIS P 8113) and a thickness of 300 μm, and an adhesive was applied so that the thickness of the tape after drying was 395 μm. An adhesive tape was manufactured in the same manner as in Example 2 except for the above.

[Comparative example 1]
The base material was composed of a sheet containing 70% by mass of pulp and 30% by mass of vinylon fiber, the base material was impregnated with styrene-butadiene copolymer rubber, and the thickness of the tape after drying was 140 μm. An adhesive tape was produced in the same manner as in Example 1, except that the adhesive was applied so that the adhesive was applied. The Japanese paper, which has been impregnated with styrene-butadiene copolymer rubber and 30% of the fibers of the Japanese paper are changed from pulp to vinylon, has a thickness of 85 μm, and is determined according to the tensile elongation at break test method of JIS P 8113. The elongation rate was 8.0%.

[Comparative example 2]
An adhesive tape was produced in the same manner as in Example 1 except that the polymethylpentene film was replaced with a polypropylene film having a surface tension of 34 mN/cm.

[Comparative example 3]
An adhesive tape was produced in the same manner as in Example 2 except that the polymethylpentene film was replaced with a polyethylene film having a surface tension of 32 mN/cm.

[Comparative example 4]
"No. 3303HG" manufactured by Kamoi Kakoshi Co., Ltd. was used as a general washi paper masking tape.

[Comparative example 5]
"Vistac No. 2000" manufactured by Kamoi Kakoshi Co., Ltd. was used as a general craft tape.

[Comparative example 6]
A commercially available adhesive tape was used to prevent sealants from adhering on three sides. The base material of this adhesive tape is composed of a polyethylene film. The thickness of the adhesive tape is 110 μm. Acrylic adhesive is used as the adhesive.

The physical properties of the adhesive tapes according to each Example and the adhesive tapes according to Comparative Examples obtained by the above method were evaluated by the following method, and the results are summarized in Table 1.

(Growth rate)
By a method based on JIS Z 0237, a synthetic resin layer was laminated on a base material, and an elongation rate was determined for an adhesive tape coated with an adhesive.

(Adhesive force)
Adhesive strength to a stainless steel plate was measured by a method based on JIS Z 0237.

(Ratio of adhesive layer)
The ratio of the adhesive layer was determined using the following formula.
Adhesive layer thickness (%) = Adhesive layer thickness (μm) ÷ Base material thickness (μm) × 100

(Mold releasability against modified silicone sealant (with primer))
The adhesive tape according to each Example or each Comparative Example was attached to a stainless steel plate, and a primer (MP1000, manufactured by Cemedine Co., Ltd.) was applied with a brush to the back of the adhesive tape, and was air-dried for 30 minutes. This primer is used for the purpose of improving the adhesive strength between the sealant filled in the joints and the exterior wall material. Usually, when it is applied to the side walls of exterior wall materials, it is also applied to the bottom of the joints.

On top of the primer coating, a modified silicone sealant (Cemedine Co., Ltd., POS Seal) was further applied to a thickness of 5 mm, and cured at room temperature for one week. Thereafter, the sealant was peeled off in the same manner as in the adhesive force test described above, and the resistance value (N/cm) at this time was determined. It can be said that the smaller the resistance value, the lighter and thinner the release, and the better the modified silicone sealing material's releasability. Table 1 shows the evaluation of the mold releasability of modified silicone sealants when applying an undercoat based on the following criteria.
○...0 N/cm or more and less than 0.3 N/cm △...0.3 N/cm or more and less than 1.0 N/cm ×...1.0 N/cm or more

(Mold releasability for modified silicone sealant (without primer))
The resistance value was determined in the same manner as in "Releasability against modified silicone sealant (with primer)" except that no primer was applied. The evaluation criteria for mold releasability were the same as above.

(Mold releasability for urethane sealant (with primer))
Except for changing the primer to Cemedine's sealing construction primer "MP2000" and changing the sealant to Cemedine's urethane sealing material "Urethane Seal S700NB", "Mold releasability against modified silicone sealant (with primer)" The resistance value was determined in the same manner as in ". The evaluation criteria for mold releasability were the same as above.

(Releasability of urethane sealant (without primer))
The resistance value was determined in the same manner as in "Mold releasability to urethane sealant (with primer)" except that no primer was applied. The evaluation criteria for mold releasability were the same as above.

(Easy to cut by hand)
A sensory evaluation was performed on the ease of cutting the tape by hand. The evaluation criteria are as follows.
○...Easy to cut without resistance.
△...There is resistance, but it can be cut.
×: Difficult to cut due to stretching and resistance.

(Adhesive protrudes during pasting)
When the adhesive tape was attached to an adherend, the extent to which the adhesive protruded from the edge of the tape was visually checked and evaluated. The evaluation criteria are as follows.
○: No protrusion is observed.
×...Protrusion is seen.

As shown in Table 1, the adhesive tapes of Examples 1 to 3 have low elongation rates when tensile force is applied. When adhesive tape was actually applied to the bottom of the joint, the adhesive tapes according to Examples 1 to 3 showed no problems when pulling out the adhesive tape from the tape roll or when tearing and cutting the adhesive tape by hand. The adhesive tape did not stretch, and the adhesive tape could be attached to the bottom of the joint without any gaps. The adhesive tapes of Examples 1 to 3 did not shrink even after time had passed since they were pasted. The adhesive tape according to Comparative Example 1 stretched both when the adhesive tape was pulled out from the tape roll and when the adhesive tape was torn and cut by hand. As a result, a gap was created when applying the adhesive tape to the bottom of the joint. After a while after applying the adhesive tape of Comparative Example 1, the stretched adhesive tape returned to its original shape, resulting in partial peeling of the adhesive tape and an enlarged gap. In the adhesive tape of Comparative Example 6, problems caused by elongation and shape restoration were more pronounced. The adhesive tape of Example 4 had poor hand-cutting properties compared to the adhesive tapes of Example 1 and the like, so it was necessary to use a knife during construction. However, when the adhesive tape of Example 4 was pulled out from the tape roll, the adhesive tape did not stretch and was able to be properly attached to the bottom of the joint.

When adhesive tape was actually applied to the bottom of the joint, the adhesive tapes of Examples 1 to 5 exhibited excellent mold releasability regardless of the presence or absence of a primer and the type of sealant, resulting in three-sided adhesion. was able to be prevented. When the adhesive tapes of Examples 1 to 5 were used, there was no need to mask the bottom portions of the joints when applying the primer. On the other hand, in the adhesive tapes of Comparative Examples 2 and 3, the adhesive tape and the sealant were adhered to each other via the primer. When using the adhesive tapes of Comparative Examples 2 and 3, it was necessary to mask the bottom portions of the joints.

3 Adhesive tape 31 Base material 32 Synthetic resin layer 33 Adhesive layer

Claims (4)

An adhesive tape having a base material made of Japanese paper or kraft paper, a synthetic resin layer placed on one side of the base material, and an adhesive layer placed on the other side of the base material,
The critical surface tension of the synthetic resin layer is 30 mN/m or less,
The tensile elongation rate of the adhesive tape according to JIS Z 0237 is 8% or less,
The synthetic resin layer is an adhesive tape for preventing three-sided adhesion of a sealant whose main component is polymethylpentene . The adhesive tape for preventing three-sided adhesion of a sealant according to claim 1, wherein the base material has a thickness of 25 to 200 μm. The adhesive tape for preventing three-sided adhesion of a sealant according to claim 1 or 2, wherein the synthetic resin layer has a thickness of 2 to 50 μm. The adhesive layer contains at least one of a rubber adhesive, an acrylic adhesive, and a urethane adhesive,
The adhesive tape for preventing three-sided adhesion of a sealant according to any one of claims 1 to 3, wherein the thickness of the adhesive layer is 20 to 200% of the thickness of the base material.

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