ADHESIVE TAPE

Abstract

The present invention relates to an adhesive tape comprising a base material layer made of a flat yarn cloth, a first film layer made of a thermoplastic resin film layered on one surface of the base material layer, a second film layer made of a thermoplastic resin film layered on the other surface of the base material layer, and an adhesive layer layered on the surface of the second film layer opposite to the base material layer, in which the first film layer and the second film layer both contains a pigment.

Claims

1. An adhesive tape comprising: a base material layer made of flat yarn cloth, a first film layer made of a thermoplastic resin film laminated on one surface of the base material layer, a second film layer made of a thermoplastic resin film laminated on the other surface of the base material layer, and an adhesive layer laminated on the surface of the second film layer opposite to the base material layer, wherein the first film layer and the second film layer both contain a pigment.

2. The adhesive tape according to claim 1, wherein a content of the pigment in the first film layer and a content of the pigment in the second film layer are both 1 to 10% by weight.

3. The adhesive tape according to claim 1, wherein the pigment is carbon black.

4. The adhesive tape according to claim 1, wherein the thickness of the first film layer and the thickness of the second film layer are both 10 to 100 m.

5. The adhesive tape according to claim 1, wherein the adhesive layer is made of an adhesive composition, the adhesive composition contains an acrylic polymer (a) and a crosslinking agent (b), and a gel fraction of the adhesive layer is 20 to 80% by weight.

6. An adhesive tape comprising: a base material layer made of a woven fabric or a non-woven fabric, a first film layer made of a thermoplastic resin film laminated on one surface of the base material layer, a second film layer made of a thermoplastic resin film laminated on the other surface of the base material layer, and an adhesive layer laminated on the surface of the second film layer opposite to the base material layer, wherein the first film layer and the second film layer both contain a pigment and the pigment contained in the first film layer is a black pigment.

7. The adhesive tape according to claim 6, wherein the woven fabric is flat yarn cloth.

8. The adhesive tape according to claim 6, wherein a content of the black pigment in the first film layer is 1 to 10% by weight.

9. The adhesive tape according to claim 6, wherein a content of the pigment in the second film layer is 1 to 10% by weight.

10. The adhesive tape according to claim 6, wherein the pigment is carbon black.

11. The adhesive tape according to claim 6, wherein the thickness of the first film layer is 10 to 100 m.

12. The adhesive tape according to claim 6, wherein a ratio of the thickness of the first film layer to the thickness of the second film layer (thickness of the first film layer/thickness of the second film layer) is less than 2.

13. The adhesive tape according to claim 6, wherein the adhesive layer is made of an adhesive composition, the adhesive composition contains an acrylic polymer (a) and a crosslinking agent (b), and a gel fraction of the adhesive layer is 20 to 80% by weight.

Description

EXAMPLES

[0117] Hereinafter, the present invention will be described further more concretely by ways of Examples, but the present invention is not limited to the following Examples, unless the gist of the present invention is exceeded. In the example, part and % are based on weight.

[0118] Further, the weight average molecular weight, the dispersity, and the gel fraction of the adhesive layer of the acrylic resin (a) in the following examples were measured according to the above-mentioned method.

[0119] As the glass transition temperature of the acrylic resin (a) was calculated using the Fox equation described above, and the glass transition temperature of a homopolymer to be formed from each monomer constituting the acrylic resin (a), a literature value and a value described in a catalog thereof usually measured by DSC (differential scanning calorimetry) were used.

<Production of Acrylic Resin (a-1)>

[0120] Into a four-neck round bottom flask equipped with a reflux condenser, a stirrer, a nitrogen gas inlet and a thermometer, 30 parts of ethyl acetate and 0.02 parts of azobisisobutyronitrile (AIBN) as a polymerization catalyst were charged. The temperature was elevated with stirring, and when the internal temperature became stable at 78 C., a mixture obtained by mixing and dissolving 93 parts of 2-ethylhexyl acrylate, 5 parts of vinyl acetate, and 2 parts of acrylic acid as copolymerizing components and 0.015 parts of azobisisobutyronitrile (AIBN) as a polymerization initiator was added dropwise over a period of 2 hours and reacted under reflux. Then, 20 parts of ethyl acetate was added after 7 hours from the start of the reaction, and thereafter, 5 parts of Super Ester A-75 (manufactured by Arakawa Chemical Industries, Ltd.) was added as a tackifier and the resultant was diluted with 56 parts of ethyl acetate to obtain an acrylic resin (a-1) solution (solid content 53.0%, viscosity 10000 mPa.Math.s/25 C.).

<Preparation of Adhesive Composition>

[0121] Tetrad C (manufactured by Mitsubishi Gas Chemical Company, Inc.) as a cross-linking agent (b) was added in an amount of 0.37 parts to 100 parts of the solid content of the acrylic resin (a-1) to obtain an adhesive composition.

Example 1

<Preparation of Tape Base Material>

[0122] A flat yarn cloth was obtained as a plain-weave woven fabric using a warp yarn made of high-density polyethylene and a weft yarn made of high-density polyethylene on a water jet machine and was used as a base material layer.

[0123] High-pressure low-density polyethylene containing 4% by weight of carbon black was subjected to extrusion lamination to laminate a first film layer having a thickness of 40 m and a second film layer having a thickness of 40 m on both surfaces of the base material layer of the obtained flat yarn cloth, thereby obtaining a tape base material.

<Adhesive Tape>

[0124] The above-described adhesive composition was applied to the second film layer in the tape base material obtained above so as to have a thickness of 50 m after drying, and after drying at 80 C. for 5 minutes, the resultant was aged at 40 C. for 7 days and cut to a width of 50 mm to obtain an adhesive tape. When the gel fraction of the adhesive layer of the adhesive tape was measured, it was found to be 43% by weight.

[0125] Moreover, since the flat yarn cloth was used for the base material layer, the adhesive tape had a good hand-cutting property.

[UV Blocking Property]

[0126] Using a spectrophotometer V-7200 manufactured by JASCO Corporation, the UV transmittance of the obtained adhesive tape at a wavelength of 400 nm was measured until the number of integration times reached 16 times and evaluated based on the following criteria. The results are shown in Table 1.

Evaluation Criteria

[0127] A: less than 0.1%

[0128] B: 0.1% or more and less than 1.0%

[0129] C: 1.0% or more

[Tensile Strength and Elongation at Break]

[0130] The tensile strength and elongation at break of the obtained adhesive tape were measured at a tensile speed of 50 mm/min using an autograph AG-XPlus manufactured by Shimadzu Corporation, and evaluated based on the following criteria. The results are shown in Table 1.

Evaluation Criteria of Tensile Strength

[0131] A: 180 N/25 mm or more

[0132] B: 165 N/25 mm or more and less than 180 N/25 mm

[0133] C: less than 165 N/25 mm

Evaluation Criteria of Elongation at Break

[0134] A: 20 mm or more

[0135] C: less than 20 mm

[Curling Property]

[0136] The tape base material was cut into a film of 5 cm5 cm, and subjected to a heat treatment at 70 C. for 30 minutes in a state that the base material was placed on a horizontal table with the first film layer facing up. The raised heights of the four corners at that time were measured, an average value thereof was calculated, and the curling property was evaluated based on the following criteria. The results are shown in Table 1. Incidentally, it can be estimated that the curling property of the tape base material correlates with the curling property of the adhesive tape having the adhesive layer.

Evaluation Criteria

[0137] A: less than 5 mm

[0138] B: 5 mm or more and less than 10 mm

[0139] C: 10 mm or more

Comparative Example 1

[0140] An adhesive tape was obtained in the same manner as in Example 1 except that there was used a tape base material in which only the first film layer contained 4% by weight of carbon black and the second film layer contained no carbon black, and then the tape was evaluated. The results are shown in Table 1.

Comparative Example 2

[0141] An adhesive tape was obtained in the same manner as in Example 1 except that there was used a tape base material in which the carbon black content of the first film layer was 8% by weight (twice that in Example 1) and the second film layer contained no carbon black, and then the tape was evaluated. The results are shown in Table 1.

Comparative Example 3

[0142] An adhesive tape was obtained in the same manner as in Example 1 except that there was used a tape base material in which the thickness of the first film layer was 80 m (twice that in Example 1) and the second film layer contained no carbon black, and then the tape was evaluated. The results are shown in Table 1.

[0143] Since the tape base material of Comparative Example 3 had an excessively strong curling property, the tape base material was curled during the measurement of the curling property, and thus the curling property could not be measured.

TABLE-US-00001 TABLE 1 UV transmittance Curling property [400 nm] Tensile strength Elongation at break [70 C. 30 min] Measured Measured Measured Measured value value value value (%) Evaluation (N/25 mm) Evaluation (mm) Evaluation (mm) Evaluation Example 1 0 A 192 A 22 A 2 A Comparative 44 C 162 C 17 C 2 A Example 1 Comparative 0 A 161 C 17 C 3 A Example 2 Comparative 0 A 174 B 19 C Impossible C Example 3 to measure

[0144] From the results in Table 1, it is found that the adhesive tape of Example 1 containing the pigment in both the first film layer and the second film layer has an excellent UV blocking property, high tensile strength, large elongation at break, excellent mechanical properties, and a small curling property.

[0145] It is found that the adhesive tape of Comparative Example 1 containing the pigment only in the first film layer is inferior in the UV blocking property, and the adhesive tape of Comparative Example 2 containing a large amount of the pigment in the first film layer has a good UV blocking property, but the tensile strength and the elongation at break are lowered, the mechanical properties are inferior, and the curling property is slightly increased.

[0146] It is found that the adhesive tape of Comparative Example 3 in which the thickness of the first film layer containing the pigment is increased has a good UV blocking property and, although the decrease in mechanical properties is relatively small, the curling property is very strong.

[0147] Although the present invention has been described in detail with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the present invention. The present application is based on Japanese Patent Application No. 2018-186745 filed on Oct. 1, 2018, the contents of which are incorporated herein by reference.

INDUSTRIAL APPLICABILITY

[0148] The adhesive tape of the present invention is excellent in the hand-cutting property and the UV blocking property, and is excellent in mechanical properties and curling resistance. Therefore, it is suitably used as an adhesive tape for fixing a house wrap sheet or the like.