JP2005281360A - Double-sided adhesive tape and double-sided adhesive tape for securing interior material for construction - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a double-sided adhesive tape which is excellent in low-temperature adhesion, rough-surface adhesion and retention of adhesion and in which an interior material is not peeled off within 24 hours after it is applied even if there may occur any level difference in the surface of an underlying material or any warpage of the interior material, and to provide a double-sided adhesive tape for fixing an interior material for construction. <P>SOLUTION: The double-sided adhesive tape comprises a base material composed of a foamed body and adhesive layers formed on both sides of the base material, wherein the adhesive layers contain an acrylic copolymer having a weight average molecular weight of 700,000-2,000,000 and a tackifier; the adhesive layers have loss tangent (tan δ) that shows the maximal value (M<SB>1</SB>) at a temperature of -25°C or lower; and the double-sided adhesive tape has a retention time of 24 hours or more in the retention test thereof at 0°C. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a double-sided adhesive tape having a foam as a base material and having pressure-sensitive adhesive layers formed on both sides of the base material, and particularly relates to a double-sided adhesive tape excellent in holding power at 0 ° C.

  Conventionally, double-sided adhesive tapes have been used in various industrial fields such as home appliances, automobiles, OA equipment, and construction as a joining means that has good workability and workability and high adhesion reliability.

  For example, when building architectural interior materials such as decorative panels on a base material such as a ceiling or wall of a building, use a double-sided adhesive tape and an adhesive together. And a method for expressing the final adhesive force is used (for example, see Patent Document 1).

In this method, the double-sided adhesive tape serves to temporarily fix the decorative board until the adhesive is cured. It takes about 24 hours for the adhesive to cure.
Japanese Patent Laid-Open No. 4-312671

However, in the method for adhering the decorative board according to Patent Document 1, there are irregularities on the surface of the base material and the back surface of the interior material, and since the bonding work is almost done on site, there is a lot of dust, The surface of the material is dirty, and a general double-sided adhesive tape has a problem that a sufficient initial adhesive force cannot always be obtained.
Also, general double-sided adhesive tape has insufficient low-temperature adhesiveness, and when it is installed at a low temperature of around 0 ° C in winter, the interior material may peel off, or if there is a step on the base material surface, When the moisture is high, there is also a problem that the interior material warps and floats from the surface of the base material.

  In view of the above-mentioned problems of the prior art, the present invention is excellent in low-temperature adhesiveness, rough surface adhesiveness, and adhesiveness retention, and the interior material remains 24 hours long even if a step on the surface of the base material or warping of the interior material occurs. An object of the present invention is to provide a double-sided adhesive tape and a double-sided adhesive tape for fixing an interior material for a building that will not be peeled off before being removed.

To solve this problem,
The present invention is a double-sided adhesive tape comprising a foam as a base material and having pressure-sensitive adhesive layers formed on both sides of the base material, the pressure-sensitive adhesive layer comprising an acrylic copolymer having a weight average molecular weight of 700 to 2,000,000, The temperature of the pressure-sensitive adhesive layer containing the pressure-sensitive adhesive layer and exhibiting the maximum value (M ₁ ) of the loss tangent (tan δ) is −25 ° C. or lower, and this double-sided adhesive tape is held in a holding test at 0 ° C. The double-sided adhesive tape is characterized in that the time is 24 hours or more.

  The present invention also provides a double-sided adhesive tape for fixing a building interior material comprising the double-sided adhesive tape.

  According to the double-sided adhesive tape of the present invention and the double-sided adhesive tape for fixing an interior material for building, it has excellent low-temperature adhesiveness, rough surface adhesiveness, and adhesiveness retention, and even if a step on the surface of the base material or warping of the interior material occurs The interior material will not peel off before 24 hours.

  The double-sided adhesive tape of this invention is comprised from the base material and the adhesive layer formed in both surfaces of this base material. A release sheet may be provided on the free surface of this pressure-sensitive adhesive layer (the side opposite to the base material side). This release sheet may be provided on one side of the double-sided adhesive tape or on both sides.

  Examples of the substrate used for the double-sided adhesive tape of the present invention include non-woven fabrics, plastic films, and foams. Among these, foams are preferable from the viewpoints of excellent conformability to unevenness on the back surface of the interior material and the surface of the base material, impact absorption, and the like.

Examples of such foams include polyethylene resin foam, polyurethane resin foam, vinyl chloride resin foam, acrylic resin foam, polyamide resin foam, ethylene-vinyl acetate copolymer resin foam, and chloroprene rubber foam. Body, butyl rubber foam, styrene-butadiene copolymer rubber foam, natural rubber foam and the like.
Among these, in consideration of conformity to unevenness on the back surface of the interior material and the surface of the base material, buffer absorbability, hand cutting properties (easy cutting when the operator cuts by hand), etc., polyethylene resin foam, polyurethane A resin foam, an acrylic resin foam or the like is preferable.
Moreover, the thickness of this base material is preferably 0.4 to 2 mm, and more preferably 0.5 to 1 mm.

The pressure-sensitive adhesive layer has a temperature at which the loss tangent (tan δ) has a maximum value (M ₁ ) of −25 ° C. or lower, preferably −27 ° C. or lower.
Here, the loss tangent (tan δ) is obtained from the equation of tan δ = E ₂ / E ₁ from the storage elastic modulus E ₁ and the loss elastic modulus E ₂ obtained by dynamic viscoelasticity measurement by temperature dispersion. From the dynamic viscoelasticity measurement by temperature dispersion, the maximum value (M ₁ ) of the loss tangent (tan δ) at a certain frequency is obtained. The temperature at which this maximum value (M ₁ ) is shown substantially matches the glass transition temperature.
Under temperature conditions lower than the temperature at which this maximum value (M ₁ ) is exhibited, the pressure-sensitive adhesive layer is in a glass state and does not exhibit tackiness. Therefore, considering that the construction is performed at a low temperature of around 0 ° C. in winter, if the temperature at which the loss tangent (tan δ) of the adhesive layer shows the maximum value (M ₁ ) is lower than the working environment temperature, the adhesive layer is made of glass. Adhesion can be maintained even at low temperatures without causing transition.
Since the temperature showing the maximum value (M ₁ ) of the loss tangent (tan δ) of the pressure-sensitive adhesive layer according to the present invention is −25 ° C. or less, it is possible to exhibit sufficient adhesiveness even at low temperatures (low temperature adhesiveness). it can.

The pressure-sensitive adhesive forming this pressure-sensitive adhesive layer contains an acrylic copolymer having a weight average molecular weight of 700 to 2,000,000 and a tackifier. The weight average molecular weight of this acrylic copolymer is 700,000 to 2,000,000, preferably 750,000 to 1,300,000 in terms of polystyrene measured by gel permeation chromatography (GPC).
If the weight average molecular weight is less than 700,000, the cohesive strength of the pressure-sensitive adhesive layer may be insufficient, and the interior material applied to the wall may shift. In summer, the pressure-sensitive adhesive protrudes from the cross-section of the wound tape. This is because workability at the time decreases. Further, even when the cohesive force is adjusted by using a crosslinking agent in order to obtain cohesive force, the flowability of the pressure-sensitive adhesive is lowered, so that the low-temperature adhesiveness and the pressure-sensitive adhesiveness are lowered.
On the other hand, when the weight average molecular weight exceeds 2 million, the viscosity of the pressure-sensitive adhesive becomes too high and the coating suitability is lowered.

The acrylic copolymer is a (meth) acrylic copolymer having a maximum value (M ₂ ) of loss tangent (tan δ) in a temperature range of −50 to −30 ° C., preferably −45 to −35 ° C. It is preferably a coalescence.
In the present specification, (meth) acrylic acid means acrylic acid or methacrylic acid, and the same applies to acrylic acid or methacrylic acid derivatives.

The temperature at which the maximum value (M ₂ ) of the loss tangent (tan δ) of the (meth) acrylic copolymer is −50 to −30 ° C. is that the (meth) acrylic copolymer is less than −50 ° C. This is because the cohesive strength of the coalescence is extremely reduced. On the other hand, when the temperature exceeds −30 ° C., the temperature becomes close to the temperature (−25 ° C. or less) showing the maximum value (M ₁ ) of the loss tangent (tan δ) of the pressure-sensitive adhesive layer. This is because the property is lowered.
Usually, when a tackifier is contained, the temperature showing the maximum value (M ₁ ) of the loss tangent (tan δ) of the pressure-sensitive adhesive layer tends to increase. The temperature showing the maximum value (M ₁ ) of the loss tangent (tan δ) of the pressure-sensitive adhesive layer in the present invention is −25 ° C. or less, but a certain amount of a tackifier is used as the pressure-sensitive adhesive in order to maintain the adhesion retention. It is necessary to add. At that time, in order to prevent the temperature showing the maximum value (M ₁ ) of the loss tangent (tan δ) of the pressure-sensitive adhesive layer from rising from −25 ° C., the loss tangent (tan δ) of the (meth) acrylic copolymer It is preferable that the temperature range of the local maximum value (M ₂ ) be within the above range.

The kind of (meth) acrylic copolymer having a maximum value of loss tangent (M ₂ ) of −50 to −30 ° C. is not particularly limited, but (a) carbon 90 to 99.9 parts by mass of (meth) acrylic acid alkyl ester having 1 to 14 alkyl side chains, (b) 0.01 to 1.0 part by mass of a monomer containing a hydroxy group, (c) a hydroxy group It is preferable that it is a (meth) acrylic-type copolymer which has 0.1-6.0 mass parts of monomers which have polar groups other than as a main component.

Specific examples of (a) (meth) acrylic acid alkyl ester having an alkyl side chain having 1 to 14 carbon atoms include methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, and n-butyl. Acrylate, sec-butyl acrylate, t-butyl acrylate, n-hexyl acrylate, cyclohexyl acrylate, n-octyl acrylate, isooctyl acrylate, 2-ethylhexyl acrylate, isononyl acrylate, isodecyl acrylate, lauryl acrylate, methyl methacrylate, ethyl methacrylate , N-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, sec-butyl methacrylate, t-butyl methacrylate n- hexyl methacrylate, cyclohexyl methacrylate, n- octyl methacrylate, isooctyl methacrylate, 2-ethylhexyl methacrylate, isononyl methacrylate, isodecyl methacrylate, lauryl methacrylate and the like.
Among them, a methacrylic acid alkyl ester having an alkyl side chain having 4 to 9 carbon atoms or an acrylic acid alkyl ester having an alkyl side chain having 4 to 9 carbon atoms is preferable, and the alkyl side having 4 to 9 carbon atoms is preferred. More preferred are alkyl acrylates having a chain.

Next, (b) as a monomer containing a hydroxy group, specifically, 2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, hydroxypropyl ( Examples include (meth) acrylate, caprolactone-modified (meth) acrylate, polyethylene glycol mono (meth) acrylate, and polypropylene glycol (meth) acrylate.
Among these, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, and caprolactone-modified (meth) acrylate are preferable.

  Specific examples of the monomer (c) having a polar group other than hydroxy group include acrylic acid, methacrylic acid, itaconic acid, maleic acid, crotonic acid, acrylic acid dimer, ethylene oxide-modified succinic acid acrylate and the like. Monomer having a group, N-vinyl-2-pyrrolidone, n-vinylcaprolactam, acryloylmorpholine, acrylamide, N, N-dimethylacrylamide, monomer having an amide group such as 2- (perhydrophthalimido-N-yl) ethyl acrylate , Acrylonitrile, maleic anhydride, itaconic anhydride and the like.

Further, if the temperature showing the maximum value (M ₂ ) of the loss tangent (tan δ) of the (meth) acrylic copolymer is within the above-mentioned range, other vinyl-based copolymers such as vinyl acetate and styrene are available. A monomer may be added.

The (meth) acrylic copolymer used in the present invention can be polymerized by known radical polymerization methods such as solution polymerization, bulk polymerization, emulsion polymerization, suspension polymerization and supercritical polymerization.
As the polymerization initiation method, a peroxide type such as benzoyl peroxide or lauroyl peroxide, a thermal initiation method using an azo type initiator such as azobisisobutylnitrile, an acetophenone type, a benzoin type, a benzyl ketal type The starting method using ultraviolet rays such as acylphosphine oxide, benzophenone, and maleimide, and the starting method using an electron beam can be arbitrarily selected.
Of these, the thermal initiation method using benzoyl peroxide or azobisisobutyl nitrile is most preferred.

The tackifier used in the present invention is preferably a polymerized rosin ester or terpene phenol.
The polymerized rosin ester is an ester of a dimer of rosin acid and a polyhydric alcohol, and is a resin having a softening point of 120 to 170 ° C. Among them, an ester of polymerized rosin and glycerin and an ester of polymerized rosin and pentaerythritol are preferable, and those having a softening point of resin of 140 ° C. or less are particularly preferable.
Moreover, as terpene phenol, resin with a softening point of 80-130 degreeC is preferable.

In the pressure-sensitive adhesive of the present invention, the compounding amount of the tackifier with respect to 100 parts by mass of the (meth) acrylic copolymer is preferably 1 to 25 parts by mass, and 5 to 20 parts by mass. More preferred. This is because, if the blending amount of the tackifier is less than 1 part by mass, the adhesion retention is reduced, and if it exceeds 25 parts by mass, the loss tangent (tan δ) maximum value (M ₁ ) of the adhesive layer is exhibited. This is because the temperature exceeds -25 ° C.
Various additives, antioxidants, ultraviolet absorbers, fillers, pigments, thickeners and the like may be added to the pressure-sensitive adhesive as long as the performance is not impaired.

A pressure-sensitive adhesive layer coating solution (pressure-sensitive adhesive solution) prepared by dissolving this pressure-sensitive adhesive in an organic solvent is applied to both surfaces of the substrate to form a pressure-sensitive adhesive layer.
The organic solvent used in this adhesive solution is not particularly limited as long as the above-described blending components dissolve and do not react with the functional group of the crosslinking agent, but ethyl acetate, toluene, xylene, n-hexane, Known and commonly used organic solvents such as acetone and methyl ethyl ketone can be used alone or in combination.
Of these, ethyl acetate, n-hexane, acetone, and methyl ethyl ketone are preferable.

In order to increase the cohesive force of the pressure-sensitive adhesive layer, it is preferable to crosslink the pressure-sensitive adhesive. As a method for crosslinking the pressure-sensitive adhesive, a publicly known and commonly used method can be used, but it is preferable to perform crosslinking by adding a crosslinking agent. Examples of such a crosslinking agent include an isocyanate crosslinking agent, an epoxy crosslinking agent, a metal chelate crosslinking agent, and an aziridine crosslinking agent. Of these, isocyanate-based crosslinking agents and epoxy-based crosslinking agents that are highly reactive with (meth) acrylic copolymers are preferred.
The degree of crosslinking is adjusted so that the gel fraction as an index thereof is preferably in the range of 25 to 70%, more preferably 35 to 55%, and most preferably 40 to 50%. This is because if the gel fraction is less than 25%, the cohesive force of the pressure-sensitive adhesive is low and the processability is poor, and if it exceeds 70%, the adhesive retention is reduced.
This gel fraction is a value expressed as a percentage by dividing the mass of the residual gel when the double-sided adhesive tape is immersed in toluene for 24 hours by the mass before immersion.
The addition amount of the crosslinking agent is appropriately adjusted based on the target gel fraction.

  In order to form this pressure-sensitive adhesive layer, the pressure-sensitive adhesive solution may be applied directly to both surfaces of the substrate with a roll coater or die coater and dried and bonded to the release treatment surface of the release sheet. Alternatively, a method may be used in which a pressure-sensitive adhesive layer is once formed by coating and drying on the mold-treated surface, and then this is bonded to the substrate surface and transferred to the substrate side.

  The coating thickness of this pressure-sensitive adhesive is preferably 45 to 150 μm on one side, more preferably 50 to 100 μm, and most preferably 55 to 90 μm in terms of the film thickness after drying. This is because if the film thickness after drying is less than 45 μm, the adhesive strength with the interior material is reduced, and if it exceeds about 150 μm, it becomes excessive coating and the productivity is reduced.

Examples of the release sheet include synthetic resin films such as polyethylene, polypropylene, and polyethylene terephthalate (PET), paper, fine paper, nonwoven fabric, cloth, foamed sheet, and laminates thereof. Among these, paper, high-quality paper, and a laminate of polyethylene resin on both sides of paper are preferable from the viewpoint of hand cutting.
In addition, the surface of the release sheet is preferably subjected to a release treatment such as silicone treatment, long-chain alkyl treatment, or fluorine treatment in order to improve the peelability from the pressure-sensitive adhesive layer. Among these, silicone treatment is more preferable.

  The double-sided adhesive tape of the present invention has a retention time of 24 hours or longer in a retention test at 0 ° C. In the present specification, the fact that the holding time in the holding test at 0 ° C. is 24 hours or more is described as “high adhesion holding property”. The “holding test at 0 ° C.” refers to an accelerated test for measuring the adhesion holding property between the interior material and the base material with the double-sided adhesive tape in the 0 ° C. atmosphere shown in FIG.

  In this test method, first, the double-sided adhesive tape 1 of the present invention, an interior material (decorative board, etc.) 2 of a predetermined size, and a base material (gypsum board, etc.) 3 are left in a 0 ° C. atmosphere for 1 hour or longer. To do.

  Next, in a 0 ° C. atmosphere, the double-sided adhesive tape 1 is affixed to a position 3 cm from the end of the back surface of the interior material 2, and this is pressurized with a 1 kg roller. Thereafter, the free surface of the double-sided adhesive tape 1 is immediately applied to the base material 3 so that the end of the double-sided adhesive tape 1 and the end of the base material 3 are aligned. Next, a weight of 1 kg is placed on the interior material 2 and is pressed for 5 seconds to adhere the interior material 2 and the base material 3 with the double-sided adhesive tape 1.

  Thereafter, as shown in FIG. 1, the substrate is placed horizontally with the base material 3 facing upward, and a load 4 of 200 g is loaded on the end of the interior material 2 where the double-sided adhesive tape 1 is not applied. 1 and the holding time until it falls off the base material 3 and falls.

When this holding time is 24 hours or more which is a guideline until the adhesive is cured, the ability to hold adhesiveness even in a low temperature environment is high. Therefore, this double-sided adhesive tape can sufficiently fulfill the role of temporarily fixing the interior material until the adhesive is cured.
Furthermore, since this test is an acceleration condition in which a load of 200 g is loaded on the end of the interior material, if this holding time is 24 hours or more, for example, the base material surface is bonded and held where there is a step. Even in such a case, the interior material does not peel off before 24 hours have passed, and even if the interior material is warped during adhesion holding due to moisture or the like, the interior material does not float from the surface of the base material.

  Hereinafter, the present invention will be described in more detail by way of examples. The present invention is not limited to the following examples.

[Example 1]
<Preparation of adhesive solution A>
In a reaction vessel equipped with a stirrer, cold flow cooler, thermometer, dropping funnel and nitrogen gas inlet, 44.9 parts by mass of butyl acrylate, 50 parts by mass of 2-ethylhexyl acrylate, 2 parts by mass of acrylic acid, 3 parts by mass of vinyl acetate 4-hydroxybutyl acrylate (0.1 part by mass) and 2,2′-azobisisobutylnitrile (0.1 part by mass) as a polymerization initiator were added, and these were dissolved in 100 parts by mass of ethyl acetate.
Next, this solution was polymerized at 70 ° C. for 10 hours to obtain an acrylic copolymer solution having a mass average molecular weight of 800,000. Table 1 shows the temperature of the pressure-sensitive adhesive solution and the maximum value (M ₂ ) of the loss tangent (tan δ) of the acrylic copolymer.

  Next, to 100 parts by mass of this acrylic copolymer, 10 parts by mass of polymerized rosin pentaerythritol ester (Pencel D135 manufactured by Arakawa Chemical Co., Ltd.) is added as a tackifier, and ethyl acetate is added to mix them uniformly. As a result, an adhesive solution A having a nonvolatile content of 45% by mass was obtained.

<Production of double-sided adhesive tape>
To 100 parts by mass of this pressure-sensitive adhesive solution A, 1.1 parts by mass of an isocyanate-based crosslinking agent having a solid content of 45% by mass (Coronate L-45 manufactured by Nippon Polyurethane Co., Ltd.) was added and stirred for 15 minutes.
Thereafter, this was coated on a release sheet made of high-quality paper having a release treatment on both sides so as to have a dry thickness of 85 μm, and dried at 80 ° C. for 3 minutes to form an adhesive layer. Table 1 shows the amount of the crosslinking agent added and the thickness of the pressure-sensitive adhesive layer.
Next, this pressure-sensitive adhesive layer was laminated and bonded to both sides of a 1 mm thick polyethylene foam (10-fold expansion) with corona treatment on both sides, and this was aged at 40 ° C. for 2 days. Obtained.

<Evaluation of pressure-sensitive adhesive layer 1-Dynamic viscoelasticity measurement of pressure-sensitive adhesive layer>
Aged in the state of the pressure-sensitive adhesive layer (pressure-sensitive adhesive single layer), this was laminated to a thickness of about 2 mm to produce a test piece. A viscoelasticity tester (ARES 2kSTD, manufactured by T.A. Instruments Japan Co., Ltd.) is mounted with a parallel plate with a diameter of 7.9 mm, and this test piece is sandwiched with a compression load of 40-60 g, with a frequency of 1 Hz, -60-100 A temperature showing a maximum value (M ₁ ) of the loss tangent (tan δ) was measured under the temperature range of ° C.

<Evaluation of adhesive layer 2-Measurement of gel fraction>
After aging in the state of the pressure-sensitive adhesive layer (pressure-sensitive adhesive single layer), it was laminated on a 50 μm polyethylene terephthalate (PET) film to prepare a test piece. This test piece was immersed in toluene for 24 hours, and the mass of the residual gel was divided by the mass before immersion and calculated as a percentage.

<Evaluation of double-sided adhesive tape 3-Retaining test of decorative board at 0 ° C. (adhesion retention)>
25 mm wide × 100 mm long decorative panel (Daiken Kogyo Kabe tile, 6 mm thick), 20 mm wide × 50 mm long, 1 mm thick double-sided adhesive tape of the present invention, gypsum board as a base material (manufactured by Yoshino Gypsum Co., Ltd.) ) Was left in an atmosphere of 0 ° C. for 1 hour or longer.
Next, in an atmosphere of 0 ° C., a double-sided adhesive tape was applied at a position 3 cm from the end of the back surface of the decorative board, and this was pressurized with a 1 kg roller. Then, the free surface of the double-sided adhesive tape was stuck on the gypsum board so that the end part of the double-sided adhesive tape and the end part of the gypsum board were combined. Subsequently, 1 kg of weight was put on the decorative board, it pressurized for 5 seconds, and the decorative board and the gypsum board were adhere | attached with the double-sided adhesive tape.

Next, as shown in FIG. 1, the gypsum board is placed on the top and placed horizontally, a load of 200 g is loaded on the end of the decorative board where the double-sided adhesive tape is not applied, and the decorative board peels off from the gypsum board together with the double-sided adhesive tape. The holding time until falling and the floating height L at the end portion between the gypsum board and the double-sided adhesive tape every hour were measured. This floating height measurement value L is a value including the thickness of the double-sided adhesive tape, and the thickness of the double-sided adhesive tape is about 1 mm including the pressure-sensitive adhesive layer. In order to show the drop time in the graph, the height of the drop time was also plotted as 1 mm. FIG. 2 shows a graph in which the relationship between the holding time and the floating height is plotted.
In addition, Table 1 shows the holding time until dropping and the floating height after 12 hours. In addition, when it hold | maintained also after 24 hours, a test was complete | finished, the evaluation result was evaluated as "> 24 hours", and it described in Table 1.

<Evaluation of double-sided adhesive tape 4-Adhesive strength to decorative plate>
A PET film having a thickness of 25 μm was laminated on one side of a double-sided adhesive tape, and this was cut into a width of 20 mm × 100 mm to prepare a test piece. The test piece and the decorative board were left in an atmosphere of 0 ° C. for 1 hour or longer.
Next, the test piece was pressure-bonded to the back of the decorative board with a 1 kg roller by one-way pressurization, left for 1 hour, and then pulled by a tensile tester (Orientec Co., Ltd.) at a speed of 300 mm / min in the 90 ° direction. The peel adhesive strength (N / 20 mm) was measured.

<Evaluation of double-sided adhesive tape 5-shear retention>
A PET film having a thickness of 25 μm was laminated on one side of a double-sided adhesive tape, and this was cut into a width of 20 mm × 100 mm to prepare a test piece. In an atmosphere of 23 ° C. and 50% relative humidity, this test piece was attached to a stainless steel plate so that the application area was 20 mm square, and left for 1 hour.
Thereafter, a load of 500 g was applied in the shear direction of the test piece in an atmosphere of 40 ° C., and the time for the test piece to fall was measured. A test piece that did not fall after 24 hours or more was evaluated as “> 24 hours”.

Table 1 shows the results of the temperature, the gel fraction, the adhesion holding property of the decorative plate, the adhesive strength against the decorative plate, and the shear holding force, which show the maximum value (M ₁ ) of the loss tangent (tan δ) of the pressure-sensitive adhesive layer.

[Example 2]
<Preparation of adhesive solution B>
In the same reaction vessel as in Example 1, 96.9 parts by mass of 2-ethylhexyl acrylate, 3 parts by mass of acrylic acid, 0.1 part by mass of 4-hydroxybutyl acrylate, and 2,2′-azobisisobutyl as a polymerization initiator 0.1 parts by mass of nitrile was added, and these were dissolved in 100 parts by mass of ethyl acetate.
Subsequently, this solution was polymerized in the same manner as in Example 1 to obtain an acrylic copolymer solution having a mass average molecular weight of 900,000.

  Next, 15 parts by mass of terpene phenol (YS Polystar T100 manufactured by Yasuhara Chemical Co., Ltd.) as a tackifier is added to 100 parts by mass of the solid content of the acrylic copolymer solution, and these are uniformly mixed by adding ethyl acetate. As a result, an adhesive solution B having a nonvolatile content of 45% was obtained.

<Production and evaluation of double-sided adhesive tape>
A double-sided adhesive tape was prepared in the same manner as in Example 1 except that 0.6 parts by mass of an epoxy crosslinking agent (E-5CM manufactured by Soken Chemical Co., Ltd.) was added to 100 parts by mass of the adhesive solution B.
The pressure-sensitive adhesive layer and the double-sided adhesive tape were evaluated in the same manner as in Example 1.
Kind of pressure-sensitive adhesive solution, temperature showing the maximum value (M ₂ ) of loss tangent (tan δ) of acrylic copolymer, addition amount of crosslinking agent, thickness of pressure-sensitive adhesive layer, loss tangent of pressure-sensitive adhesive layer (tan δ) Table 1 shows the temperature, gel fraction, adhesion retention of the decorative board, adhesion to the decorative board, and shear retention of the maximum value (M ₁ ).
Moreover, the relationship between the holding time and the floating height in the holding test at 0 ° C. of the decorative board is shown in the graph of FIG.

[Example 3]
<Production and evaluation of double-sided adhesive tape>
A double-sided adhesive tape was produced in the same manner as in Example 1 except that the pressure-sensitive adhesive solution A was used so that the dry thickness of the pressure-sensitive adhesive layer was 60 μm.
The pressure-sensitive adhesive layer and the double-sided adhesive tape were evaluated in the same manner as in Example 1.
Table 1 shows the types of the pressure-sensitive adhesive solution and the evaluation results of the pressure-sensitive adhesive layer and the double-sided adhesive tape. Moreover, the relationship between the holding time and the floating height in the holding test at 0 ° C. of the decorative board is shown in the graph of FIG.

[Comparative Example 1]
<Preparation of adhesive solution C>
A pressure-sensitive adhesive solution C having a non-volatile content of 45% was obtained in the same manner as in Example 1 except that the polymer rosin pentaerythritol ester (Pencel D135 manufactured by Arakawa Chemical Co., Ltd.) as a tackifier was not added.

<Production and evaluation of double-sided adhesive tape>
A double-sided adhesive tape was produced in the same manner as in Example 1 except that the adhesive solution C was used.
The pressure-sensitive adhesive layer and the double-sided adhesive tape were evaluated in the same manner as in Example 1.
Table 1 shows the types of the pressure-sensitive adhesive solution and the evaluation results of the pressure-sensitive adhesive layer and the double-sided adhesive tape. Moreover, the relationship between the holding time and the floating height in the holding test at 0 ° C. of the decorative board is shown in the graph of FIG.

[Comparative Example 2]
<Preparation of adhesive solution D>
A pressure-sensitive adhesive solution D having a non-volatile content of 45% was obtained in the same manner as in Example 2 except that terpene phenol (YS Hara Chemical Co., Ltd. YS Polystar T100) as a tackifier was not added.

<Production and evaluation of double-sided adhesive tape>
A double-sided adhesive tape was produced in the same manner as in Example 1 except that 1.2 parts by mass of an isocyanate crosslinking agent (Coronate L-45) was added using the adhesive solution D.
The pressure-sensitive adhesive layer and the double-sided adhesive tape were evaluated in the same manner as in Example 1.
Table 1 shows the types of the pressure-sensitive adhesive solution and the evaluation results of the pressure-sensitive adhesive layer and the double-sided adhesive tape. Moreover, the relationship between the holding time and the floating height in the holding test at 0 ° C. of the decorative board is shown in the graph of FIG.

[Comparative Example 3]
<Production and evaluation of double-sided adhesive tape>
A double-sided adhesive tape was produced in the same manner as in Example 1 except that the pressure-sensitive adhesive solution A was used so that the dry thickness of the pressure-sensitive adhesive layer was 40 μm.
The pressure-sensitive adhesive layer and the double-sided adhesive tape were evaluated in the same manner as in Example 1.
Table 1 shows the types of the pressure-sensitive adhesive solution and the evaluation results of the pressure-sensitive adhesive layer and the double-sided adhesive tape. Moreover, the relationship between the holding time and the floating height in the holding test at 0 ° C. of the decorative board is shown in the graph of FIG.

[Comparative Example 4]
<Production and evaluation of double-sided adhesive tape>
A double-sided adhesive tape was prepared in the same manner as in Example 1 except that 0.5 parts by mass of an isocyanate-based crosslinking agent (Coronate L-45) was added using the adhesive solution A.
The pressure-sensitive adhesive layer and the double-sided adhesive tape were evaluated in the same manner as in Example 1.
Table 1 shows the types of the pressure-sensitive adhesive solution and the evaluation results of the pressure-sensitive adhesive layer and the double-sided adhesive tape. Moreover, the relationship between the holding time and the floating height in the holding test at 0 ° C. of the decorative board is shown in the graph of FIG.

[Comparative Example 5]
<Production and evaluation of double-sided adhesive tape>
A double-sided adhesive tape was produced in the same manner as in Example 1 except that 2.5 parts by mass of an isocyanate crosslinking agent (Coronate L-45) was added using the adhesive solution A.
The pressure-sensitive adhesive layer and the double-sided adhesive tape were evaluated in the same manner as in Example 1.
Table 1 shows the types of the pressure-sensitive adhesive solution and the evaluation results of the pressure-sensitive adhesive layer and the double-sided adhesive tape. Moreover, the relationship between the holding time and the floating height in the holding test at 0 ° C. of the decorative board is shown in the graph of FIG.

[Comparative Example 6]
(Adjustment of adhesive solution E)
In the same reaction vessel as in Example 1, 44.9 parts by mass of butyl acrylate, 50 parts by mass of 2-ethylhexyl acrylate, 2 parts by mass of acrylic acid, 3 parts by mass of vinyl acetate, 0.1 part by mass of 4-hydroxybutyl acrylate, 0.22 parts by mass of 2,2′-azobisisobutylnitrile was added as a polymerization initiator, and these were dissolved in 100 parts by mass of ethyl acetate.
Subsequently, this solution was polymerized at 70 ° C. for 10 hours to obtain an acrylic copolymer solution having a weight average molecular weight of 500,000.

  Next, to 100 parts by mass of this acrylic copolymer, 10 parts by mass of polymerized rosin pentaerythritol ester (Pencel D135 manufactured by Arakawa Chemical Co., Ltd.) is added as a tackifier, and ethyl acetate is added to mix them uniformly. Thus, an adhesive solution E having a nonvolatile content of 45% by mass was obtained.

<Production and evaluation of double-sided adhesive tape>
A double-sided adhesive tape was produced in the same manner as in Example 1 except that 1.1 parts by mass of an isocyanate-based crosslinking agent (Coronate L-45) was added using the adhesive solution E.
The pressure-sensitive adhesive layer and the double-sided adhesive tape were evaluated in the same manner as in Example 1.
Table 1 shows the types of the pressure-sensitive adhesive solution and the evaluation results of the pressure-sensitive adhesive layer and the double-sided adhesive tape. Moreover, the relationship between the holding time and the floating height in the holding test at 0 ° C. of the decorative board is shown in the graph of FIG.

[Comparative Example 7]
<Production and evaluation of double-sided adhesive tape>
A double-sided adhesive tape was prepared in the same manner as in Example 1 except that 2.5 parts by mass of an isocyanate crosslinking agent (Coronate L-45) was added using the adhesive solution E.
The pressure-sensitive adhesive layer and the double-sided adhesive tape were evaluated in the same manner as in Example 1.
Table 1 shows the types of the pressure-sensitive adhesive solution and the evaluation results of the pressure-sensitive adhesive layer and the double-sided adhesive tape. Moreover, the relationship between the holding time and the floating height in the holding test at 0 ° C. of the decorative board is shown in the graph of FIG.

From the result of Table 1, when Examples 1-3 were compared with Comparative Examples 1-7, in the double-sided adhesive tapes of Examples 1-3, the adhesive retention of the decorative board at 0 ° C. was 24 hours or more. On the other hand, as for Comparative Examples 1-7, the decorative board dropped in 20 hours or less.
Further, when Examples 1 and 3 were compared with Comparative Example 3, the adhesive strength to the decorative plate when the thickness of the pressure-sensitive adhesive layer of Comparative Example 3 was thin was lower than that of Examples 1 and 3.
Further, when Examples 1 and 3 are compared with Comparative Example 4, Comparative Example 4 in which the addition amount is smaller than the addition amount of the crosslinking agent in Examples 1 and 3 maintains the adhesion of the decorative board at 0 ° C. Not only the properties, but also the shear holding power decreased.
Further, when Example 1 is compared with Comparative Examples 6 and 7 in which the weight average molecular weight of the pressure-sensitive adhesive is lower than that of Comparative Example 6 in which the amount of the crosslinking agent is the same as that of Example 1, the decorative board at 0 ° C. In addition to the adhesive retention, the shear retention was also reduced. Further, in Comparative Example 7, in which the gel fraction was almost the same as Example 1, not only the adhesive retention of the decorative board at 0 ° C. but also the adhesive strength to the decorative board was lowered.

  From the above results, the double-sided adhesive tape of the present invention and the double-sided adhesive tape for fixing an interior material for building are excellent in low-temperature adhesiveness and adhesiveness retention, and the interior material does not float from the surface of the base material after 12 hours. Moreover, it was confirmed that it was excellent also in the adhesive force and the shear retention force with respect to a decorative board.

It is the schematic which showed the acceleration test which measures the adhesiveness retention of the interior material and base material by a double-sided adhesive tape in 0 degreeC atmosphere. It is the graph which plotted the relationship between the retention time and the floating height in the retention test at 0 degreeC of a decorative board.

Claims (3)

In a double-sided adhesive tape with a foam as a base material, and an adhesive layer formed on both sides of the base material,
This pressure-sensitive adhesive layer contains an acrylic copolymer having a weight average molecular weight of 7,000 to 2,000,000 and a tackifier,
The temperature indicating the maximum value (M ₁ ) of the loss tangent (tan δ) of the pressure-sensitive adhesive layer is −25 ° C. or less,
A double-sided adhesive tape characterized in that the holding time in the holding test at 0 ° C. of this double-sided adhesive tape is 24 hours or more. The acrylic copolymer is a (meth) acrylic copolymer that exhibits a maximum value (M ₂ ) of loss tangent (tan δ) in a temperature range of −50 to −30 ° C.,
The double-sided adhesive tape according to claim 1, wherein the tackifier is a polymerized rosin ester or terpene phenol. A double-sided adhesive tape for fixing an interior material for building, comprising the double-sided adhesive tape according to claim 1.

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