JP7236336B2 - Curing tape - Google Patents

Description

The present invention relates to a curing tape.

Conventionally, at a construction site or the like, the finished surface is cured so that the already finished portion is not scratched, soiled, etc., and a curing tape is used for the curing. In addition, it is necessary to protect furniture and the like when moving, etc., and protection tape is widely used for protection (see, for example, Patent Document 1).

JP 2015-203032 A

The properties required for such a curing tape are that it is transparent (transparency), that the surface of the adhesive layer is sticky to some extent (tackiness), and that it exhibits sufficient adhesive strength (adhesiveness). , It must be able to be peeled off without adhesive residue even after it is attached to a curing surface and left for a long period of time (long-term peelability), and it must be peelable without the base material breaking or stretching (peelability). etc.

Conventional curing tapes are required to have improved long-term peelability and peelability.

The present invention has been made in view of such circumstances, and provides a curing tape that can improve long-term peelability and peelability.

According to the present invention, a substrate and an adhesive layer provided on the substrate are provided, the substrate is composed of a biaxially oriented polypropylene film, and the adhesive layer is styrene-isoprene-styrene. It consists of a block copolymer and an adhesive containing a tackifier, the copolymer has a styrene content of 21 to 40% by mass and a diblock ratio of 45 to 80% by mass, and the copolymer A curing tape is provided, wherein the mass ratio of said tackifier to is 0.50 to 0.75.

As a result of intensive studies, the inventors of the present invention have found that a curing tape having the base material and the pressure-sensitive adhesive layer can solve the above problems, and have completed the present invention.

1 shows the configuration of a curing tape according to one embodiment of the present invention;

Hereinafter, the curing tape of one embodiment of the present invention will be described in detail.

<curing tape>
As shown in FIG. 1, the curing tape of this embodiment includes a substrate 1 and an adhesive layer 3 provided on the substrate 1. As shown in FIG. An anchor coat layer 5 is preferably provided between the substrate 1 and the adhesive layer 3 . A release agent layer 7 is preferably provided on the surface of the substrate 1 opposite to the adhesive layer 3 .

<Base material>
The substrate 1 is preferably a polyolefin-based film from the viewpoint of transparency, and is composed of a biaxially oriented polypropylene (hereinafter referred to as "OPP") film. By providing a pressure-sensitive adhesive layer having a specific composition on such a substrate, it is possible to improve transparency, tackiness, adhesiveness, long-term peelability, peelability, and the like. The thickness of the substrate is, for example, 10-200 μm, preferably 30-100 μm. If the thickness of the base material is less than 10 μm, the strength of the base material is insufficient, so that the base material breaks during the peeling operation, which is undesirable. If the thickness of the base material is more than 200 μm, the transparency is deteriorated, and the winding diameter of the tape becomes large and heavy.

<Adhesive layer>
The adhesive layer 3 is made of an adhesive containing a styrene-isoprene-styrene block copolymer (hereinafter referred to as "SIS copolymer") and a tackifier. Various additives such as a plasticizer and an ultraviolet absorber are added to this adhesive as needed.

The SIS copolymer contains a styrene-isoprene-styrene triblock copolymer and a styrene-isoprene diblock copolymer. ~70% by mass is preferred. If the diblock ratio is too low, the stickiness of the pressure-sensitive adhesive will not be sufficient, and it will be necessary to apply a strong pressure when the curing tape is adhered, resulting in poor usability of the curing tape. On the other hand, if the diblock ratio is too high, adhesive deposits tend to occur. The diblock ratio (%) can be calculated by 100×(parts by mass of diblock copolymer)/(parts by mass of diblock copolymer+parts by mass of triblock copolymer). Specifically, the diblock ratio is obtained by measuring the molecular weight of the SIS copolymer by a gel permeation chromatography (GPC) method, and the peak attributed to the diblock copolymer in the obtained chart and the triblock It can be calculated from the area ratio of peaks attributed to the copolymer. The method for changing the diblock ratio is not particularly limited, but for example, changing the ratio of the amount of coupling agent/the amount of initiator used during polymerization, or blending two or more SIS copolymers having different diblock ratios. method.

The weight average molecular weight of the triblock copolymer is not particularly limited, but is, for example, 120,000 to 1,200,000, preferably 140,000 to 1,000,000, more preferably 160,000 to 800,000. The weight average molecular weight of the diblock copolymer is not particularly limited, but is, for example, 60,000 to 250,000, preferably 70,000 to 230,000, more preferably 80,000 to 220,000. The weight average molecular weight of the diblock copolymer is preferably smaller than the weight average molecular weight of the triblock copolymer. A weight average molecular weight can be calculated|required by the gel permeation chromatography (GPC) method.

The styrene content of the SIS copolymer is 21-40% by mass, preferably 26-35% by mass. If the styrene content is too low, the pressure-sensitive adhesive becomes soft, and when the tape is peeled off, there is a problem that adhesive remains on the adherend. On the other hand, if the styrene content is too high, the pressure-sensitive adhesive becomes hard and the tackiness of the adhesive is lowered, resulting in difficulty in sticking to the adherend. Styrene content can be measured using the method described in JIS K6383. The method for changing the styrene content is not particularly limited, but for example, a method of changing the styrene/isoprene ratio of the monomers to obtain a SIS copolymer having the desired styrene content by living anionic polymerization, or a method of obtaining a SIS copolymer having the desired styrene content by changing two or more different styrene contents. SIS is blended to obtain a SIS copolymer having the desired styrene content.

The mass ratio of tackifier to SIS copolymer is 0.50 to 0.75, preferably 0.55 to 0.70. If this value is too small, the stickiness of the pressure-sensitive adhesive will be very small, and the curing tape will be difficult to stick to the adherend. On the other hand, if this value is too large, adhesive residue is likely to occur when the curing tape is peeled off after being attached to the adherend for a long period of time.

The type of tackifier is not particularly limited, but one having excellent compatibility with the SIS copolymer is preferable. Alicyclic/aromatic petroleum resins, terpene-based resins, rosin-based resins, rosin ester-based resins, terpene-phenol resins, alkylphenol resins, etc., among which petroleum resins are preferred, and hydrogenated C9 petroleum resins are most preferred. . The reason for this is that even if the adhesive tape is used outdoors, it is less susceptible to deterioration due to exposure to direct sunlight (ultraviolet rays).

The type of plasticizer is not particularly limited, but phthalic acid-based plasticizers, isophthalic acid-based plasticizers, terephthalic acid-based plasticizers, adipic acid-based plasticizers and their polyester plasticizers, phosphoric acid-based plasticizers, trimellit Acid-based plasticizers, epoxy-based plasticizers, and the like can be used. The mass ratio of the plasticizer to the SIS copolymer is preferably 0.10-0.30, more preferably 0.15-0.25. Too little plasticizer may result in low tack, and too much plasticizer may degrade long-term peelability.

The coating amount of the pressure-sensitive adhesive layer 3 is not particularly limited, but is, for example, 10 to 100 g/m ² . If the coating amount is too small, the tackiness will be insufficient, and if it is too large, the coating performance may deteriorate.

As a method for forming the adhesive layer 3, for example, a method of heating, melting, kneading, and coating the adhesive raw material with a hot-melt coater, or dissolving the adhesive raw material in a solvent such as toluene to make it liquid, and gravure. There is a method of directly applying the pressure-sensitive adhesive onto the substrate with a coater such as a coater, a comma coater, a bar coater, a knife coater, or a roll coater.

The pressure-sensitive adhesive layer 3 may be formed on the substrate 1 or may be formed via another layer. For example, an anchor coat layer 5 may be provided between the base material 1 and the pressure-sensitive adhesive layer 3 to improve adhesion between the two. As the anchor coat agent for forming the anchor coat layer 5, various agents such as urethane-based, acrylic, imine-based, butadiene-based, olefin-based, and ethylene acrylic acid copolymer alkanol salt can be applied. A urethane-based anchor coating agent is particularly preferable from the viewpoint of improving adhesion. The coating amount of the anchor coat layer is preferably 0.005 to 0.5 g/m ² in terms of solid content, more preferably 0.01 to 0.2 g/m ² .

<Release agent layer>
In FIG. 1, it is preferable to provide a release agent layer 7 on the side of the substrate 1 on which the anchor coat layer 5 and the pressure-sensitive adhesive layer 3 are not provided. In this case, the curing tape wound up can be easily unfolded. Here, as a material that can be used for the release agent layer, conventionally known release agents can be appropriately selected and employed. There are alkyl pendant type release agents such as molecules and condensed wax type release agents, and alkyl pendant type release agents are particularly preferred.
The coating amount of the release agent is preferably 0.005 to 0.2 g/m ² in solid content, more preferably 0.01 to 0.1 g/m ² .

1. Preparation of curing tape / Example 1
A urethane-based anchor coating agent is applied to a biaxially stretched PP film to form an anchor coat layer, and an adhesive is applied thereon to a weight of 30 g/m ² to form an adhesive layer. A curing tape for evaluation was produced by.

As the adhesive, the type and amount of tackifier shown in Table 1 and a plasticizer (Monocizer W242, DIC stock company), 3 parts by weight of antioxidant (Irganox 1076, manufactured by BASF), and 1 part by weight of ultraviolet absorber (JF-77-P, manufactured by Johoku Kagaku Kogyo), and kneaded at 150 ° C. to obtain a molten pressure-sensitive adhesive, which was coated with a hot-melt coater to obtain a pressure-sensitive adhesive layer.

Other Examples/Comparative Examples Example 1 except that the base material, anchor coat layer, SIS copolymer, tackifier, and plasticizer types and/or blending amounts were changed as shown in Tables 1 and 2. A curing tape was produced in the same manner as. As in Example 1, the numerical values of the tackifier and plasticizer in each example and comparative example are parts by weight per 100 parts by weight of the SIS copolymer.

Details of various members in Tables 1 and 2 are as follows.
Biaxially oriented PP film: Biaxially oriented polypropylene film, thickness 60 μm
Uniaxially stretched PP film: Uniaxially stretched polypropylene film, thickness 60 μm
Unstretched PP film: unstretched polypropylene film, thickness 60 μm
Urethane anchor coating agent: Model EL-510 manufactured by Toyo-Morton
Acrylic anchor coating agent: Model NK polymer hydrogenated C9 petroleum resin manufactured by Shin-Nakamura Chemical Co., Ltd.: Alcon P-100 manufactured by Arakawa Chemical Co., Ltd.
C9 petroleum resin: Nisseki Neopolymer L-90 manufactured by JX Nippon Oil & Energy
C5 petroleum resin: Quinton M-100 manufactured by Nippon Zeon

2. Evaluation of Curing Tape The curing tape obtained was evaluated as follows. The results are shown in Tables 1 and 2.

As shown in Tables 1 and 2, it was found that the curing tapes of Examples had superior properties in terms of long-term peelability and peelability compared to Comparative Examples.

<Transparency>
A tape was attached to paper, and whether or not the color of the base could be seen through was evaluated according to the following criteria.
◯: The color of the base can be determined.
Δ: The color of the base is somehow discernible.
x: The color of the base cannot be determined.

<Tackiness>
The adhesive surface of the curing tape was touched with a finger, and the strength of tackiness was sensorily evaluated on a 4-grade scale.
⊚: Tack enough to stick to the adherend when the tape is applied to the adherend and lightly pressed.
◯: Tack enough to stick to the adherend when the tape is applied to the adherend and pressed firmly.
Δ: Tack enough to stick to the adherend by applying the tape to the adherend and pressing it strongly.
x: Even if the tape is applied to the adherend, the tape does not adhere to the adherend due to insufficient tackiness.

<Adhesiveness>
The adhesive strength of the curing tape was measured using the method described in "JISZ0237 10. Adhesive strength".

<Long-term peelability>
A curing tape is attached to each adherend (plywood board, acrylic board, aluminum board, PVC board), left for 3 months in an atmosphere with a temperature of 60°C and a humidity of 80%, and then cooled to room temperature (temperature of 23°C and humidity of 50%). Then, the tape was peeled off by hand, and whether or not the adhesive remained on the adherend was examined and evaluated according to the following criteria.
○: The area of the adhesive residue on the adherend with the largest area of the adhesive residue is 10% or less △: The area of the adhesive residue on the adherend with the largest area of the adhesive residue is more than 10% and 50% or less ×: Glue The area of adhesive residue on the adherend with the largest remaining area is more than 50%

<Peeling workability>
In the evaluation of long-term peelability, it was examined whether the base material was cut or stretched when the curing tape was peeled off, and evaluation was performed according to the following criteria.
◯: Neither cut nor elongation occurred in the base material.
x: Breakage or elongation occurred in the base material.

1: Substrate 3: Adhesive layer 5: Anchor coat layer 7: Release agent layer

Claims (4)

A base material and an adhesive layer provided on the base material,
The base material is composed of a biaxially oriented polypropylene film,
The pressure-sensitive adhesive layer is made of a pressure-sensitive adhesive containing a styrene-isoprene-styrene block copolymer and a tackifier,
The copolymer has a styrene content of 21 to 40% by mass and a diblock ratio of 45 to 80% by mass,
A curing tape, wherein the mass ratio of the tackifier to the copolymer is 0.50 to 0.75. The curing tape according to claim 1,
A curing tape, wherein the mass ratio of the tackifier to the copolymer is 0.55 to 0.70. The curing tape according to claim 1 or claim 2,
The adhesive contains a plasticizer,
A curing tape, wherein the mass ratio of the plasticizer to the copolymer is 0.10 to 0.30. The curing tape according to claim 3,
A curing tape, wherein the mass ratio of the plasticizer to the copolymer is 0.15 to 0.25.

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