JP2008156567A - Asphalt composition and adhesive sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an asphalt composition that has an excellent adhesivity in a temperature range of 5-50°C and is usable throughout a year even outdoors. <P>SOLUTION: The asphalt composition has a storage shear modulus of ≤1×10<SP>5</SP>Pa at 10°C at a measured frequency of 6.28 rad/second, a storage shear modulus of 4×10<SP>3</SP>Pa at 60°C and a total acid value of ≥1.5 mgKOH/g. The adhesive sheet is obtained by forming an adhesive layer composed of the asphalt composition on one side of a substrate such as a nonwoven fabric, etc. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an asphalt composition used as a pressure-sensitive adhesive and a pressure-sensitive adhesive sheet using the asphalt composition, and particularly suitable for civil engineering and building applications such as a rooftop waterproof sheet, a civil engineering waterproof sheet, and a residential waterproof and moisture-proof sheet. The present invention relates to an asphalt composition and an adhesive sheet.

  Various waterproof treatments are applied to the roof of a house, the roof of a concrete structure, etc. for the purpose of preventing water leakage. Conventionally, in such waterproofing work, a construction method has been adopted in which a waterproof layer is formed by spraying or pouring an asphalt composition that has been heated and melted into a place to be waterproofed. However, this construction method has a problem that the asphalt must be heated to a high temperature on site during construction, and odor is generated.

  Therefore, conventionally, an asphalt composition with a lower melting temperature has been proposed for waterproofing work (see, for example, Patent Document 1). Patent Document 1 includes a composition containing asphalt: 40 to 90% by mass, a mixture of polyol and polyvalent isocyanate or a reactivity imparting material such as an epoxy resin: 10 to 30% by mass, in a range of 80 to 150 ° C. An asphalt composition having a melt viscosity of 30 to 2000 mPa · sec and a softening point before reaction hardening of 60 ° C. or higher is disclosed. However, since the asphalt composition described in Patent Document 1 is a technique for forming a waterproof material by causing a curing reaction in epoxy or urethane, reaction temperature (outside temperature and material temperature), humidity and concentration (each material) If the amount of charging is not strictly adjusted, a waterproof material having desirable performance as described in Patent Document 1 cannot be obtained, but conditions such as temperature and humidity cannot be predicted, and these conditions are not stable. There is a problem that it is difficult to strictly adjust these conditions at the construction site.

  On the other hand, recently, a self-adhesive waterproof sheet in which an adhesive layer made of an asphalt composition is provided on a substrate has attracted attention. This self-adhesive waterproof sheet does not need to be heated at the time of construction and does not generate odors due to heating, so energy-saving and environmentally friendly construction methods such as Fukuoka Dome and Nagoya Dome, and general houses It has begun to be widely used as a waterproofing material for roofs, and the construction area is expected to increase further in the future.

  In general, the self-adhesive waterproof sheet is manufactured by impregnating or coating a base material such as a nonwoven fabric with an asphalt adhesive. In that case, the asphalt composition which forms an adhesion layer uses what added an elastomer and / or tackifier to asphalt (for example, refer to patent documents 2 or 3). In the waterproof sheet described in Patent Document 2, 10 to 100 parts by mass of rubber such as styrene-butadiene-styrene block copolymer (SBS) and 100 to 100 parts of tackifier such as rosin resin per 100 parts by mass of asphalt. An asphalt composition to which parts by mass are added is used. Further, in Patent Document 3, a block copolymer comprising a polymer block mainly composed of a monoalkenyl aromatic compound and a polymer block mainly composed of a conjugated diene compound, or a rubbery polymer is added to this copolymer block. Asphalt having a composition comprising: 3 to 40% by mass, tackifier such as rosin resin: 0 to 60% by mass, softener such as paraffinic process oil: 0 to 50% by mass, and 10 to 90% by mass of asphalt An adhesive composition has been proposed.

JP 2005-213981 A Japanese Patent Laid-Open No. 3-70785 JP 2006-299024 A

  However, in the conventional self-adhesive waterproof sheet, an asphalt composition which is considered to be good empirically is used, and the temperature at which the adhesiveness is exhibited is, for example, 10 to 30 ° C. or 20 at the material temperature. There is a problem that it is difficult to use throughout the year because the temperature range is about 40 ° C. and about 20 ° C. Specifically, when used outdoors, the material temperature of the adhesive layer decreases to near 0 ° C. in winter and increases to near 50 ° C. in summer. For this reason, it is necessary to select an asphalt composition according to the temperature at the time of construction. If the selection is wrong, the self-adhesive waterproof sheet is peeled off and peeled off due to insufficient adhesive strength, resulting in poor waterproofing.

  Further, the asphalt composition used in the adhesive waterproof sheet described in Patent Document 2 is a material used as an expensive sheet waterproof adhesive layer, and does not exhibit waterproof performance by itself. . For this reason, when the amount of rubber is small (5 to 8% by mass), the amount of tackifier is too large and the storage shear elastic modulus becomes small. There is a problem. In addition, since the adhesive waterproof sheet described in Patent Document 2 does not guarantee the waterproof performance with the asphalt composition alone, it is said that there is no problem in practical use, but the asphalt composition alone has the waterproof performance. It cannot be used for security purposes. Further, when blending a large amount of rubber (30 to 40% by mass), there is a problem that the viscosity of the asphalt composition becomes too high, making it difficult to produce, or requiring a dedicated production apparatus.

  On the other hand, the asphalt pressure-sensitive adhesive composition described in Patent Document 3 includes a polymer block mainly composed of a monoalkenyl aromatic compound and a polymer block mainly composed of a conjugated diene compound in order to be usable in a wide temperature range. The block copolymer is added to asphalt, and this asphalt pressure-sensitive adhesive composition has been evaluated for adhesive strength at a low temperature by a finger tack test in an atmosphere of 5 ° C. Therefore, the adhesive performance at the temperature used in actual construction as described above cannot be confirmed. Moreover, in the Example of patent document 3, only the example which mixed SBS: 13 mass% and straight asphalt: 87 mass% is shown, About the effectiveness of the mixing | blending component described in the claim Has not been verified. Therefore, when the asphalt pressure-sensitive adhesive composition described in Patent Document 3 is used, there is a possibility that excellent adhesiveness cannot be obtained in a temperature range of 5 to 50 ° C.

  The present invention has been devised in view of the above-described problems, and has an asphalt composition and an adhesive sheet that have excellent adhesiveness in a temperature range of 5 to 50 ° C. and can be used outdoors all year round. The purpose is to provide.

The asphalt composition according to the present invention has a storage shear elastic modulus of 1 × 10 ⁵ Pa or less at 10 ° C. and a storage shear elastic modulus of 4 × 10 ³ Pa or more at 60 ° C. when the measurement frequency is 6.28 rad / sec. And the total acid value is 1.5 mgKOH / g or more.

In the asphalt composition of the present invention, the storage shear modulus at 10 ° C. is 1 × 10 ⁵ Pa or less, and the storage shear modulus at 60 ° C. is 4 × 10 ³ Pa or more. can do. Moreover, since the total acid value is 1.5 mgKOH / g or more, the asphalt composition of this invention can improve adhesive force rather than the conventional asphalt composition. As a result, it is possible to exhibit excellent adhesiveness at a temperature range of 5 to 50 ° C. and wider than before.

  This asphalt composition preferably has a total acid value of 12 mgKOH / g or less.

  The pressure-sensitive adhesive sheet according to the present invention is characterized in that a pressure-sensitive adhesive layer made of the asphalt composition described above is provided on one surface of a substrate.

  In the pressure-sensitive adhesive sheet of the present invention, since the pressure-sensitive adhesive layer is formed by the asphalt composition described above, the temperature dependency of the pressure-sensitive adhesive layer is small, and excellent pressure-sensitive adhesiveness is obtained in the temperature range of 5 to 50 ° C. For this reason, even if it is used outdoors, it can be used throughout the year without causing peeling and peeling due to insufficient adhesive force.

  This adhesive sheet can use a nonwoven fabric as the base material.

  According to the present invention, the storage shear elastic modulus of the asphalt composition at 10 ° C. and 60 ° C. and the total acid value are optimized, so that excellent adhesiveness is obtained in the temperature range of 5 to 50 ° C. It is possible to use it throughout the year even in the construction in Japan.

Hereinafter, the best mode for carrying out the present invention will be described in detail. In order to solve the above-described problems and to obtain an asphalt composition exhibiting adhesiveness in a wider temperature range than before, the present inventor conducted earnest experimental research. As a result, the present inventor has found that when the storage shear elastic modulus of the asphalt composition is optimized, the temperature dependence of the tackiness of the asphalt composition is reduced. The present inventor has also found that not only the storage shear elastic modulus described above but also the surface state of the adhesive surface greatly affects the strength of the adhesive force, and in particular the presence or absence of polar groups. And while prescribing the storage shear elastic modulus at low temperature and high temperature, and by defining the physicochemical properties of the adhesive surface by the acid value, it has been found that it exhibits excellent adhesiveness in the temperature range of 5-50 ° C., The present invention has been reached. Specifically, the asphalt composition according to the present invention has a storage shear elastic modulus at 10 ° C. of 1 × 10 ⁵ Pa or less and a storage shear elastic modulus at 60 ° C. of 4 × when the measurement frequency is 6.28 rad / sec. In addition to 10 ³ Pa or more, the total acid value is 1.5 mgKOH / g or more.

  Hereinafter, the reason for the numerical limitation in the asphalt composition of the present invention will be described.

Storage shear modulus at 10 ° C. at a measurement frequency of 6.28 rad / sec: 1 × 10 ⁵ Pa or less The storage shear modulus at 10 ° C. is a guideline for tack (ease of stickiness) at low temperature (0 to 10 ° C.). Become. Specifically, when the measurement frequency is 6.28 rad / sec and the storage shear elastic modulus at 6.28 rad / sec at 10 ° C. exceeds 1 × 10 ⁵ Pa, the adhesive is sufficient at the time of adhesion and pressure bonding. For example, the area that comes into contact with the adherend such as wood, stone, cement, and non-woven fabric is reduced, and a sufficient anchoring effect cannot be obtained. Therefore, sufficient tack is achieved at low temperatures (0 to 10 ° C.). It cannot be secured. Therefore, the storage shear elastic modulus at 10 ° C. at the measurement frequency of 6.28 rad / sec is set to 1 × 10 ⁵ Pa or less.

Storage shear elastic modulus at 60 ° C. at a measurement frequency of 6.28 rad / sec: 4 × 10 ³ Pa or more The storage shear elastic modulus at 60 ° C. serves as a guide for cohesive force at high temperatures (50 to 60 ° C.). Specifically, when the measurement frequency is 6.28 rad / sec and the storage shear elastic modulus at 60 ° C. is less than 4 × 10 ³ Pa, sufficient cohesive force cannot be ensured, and a high temperature (50- 60 ° C.), even if a slight force is applied, the adhesive and the adherend are separated. Therefore, the storage shear elastic modulus at 60 ° C. at the measurement frequency of 6.28 rad / sec is set to 4 × 10 ³ Pa or more.

  The above-described storage shear elastic modulus G ′ can be measured with a dynamic viscoelasticity tester. FIG. 1 is a perspective view schematically showing a measurement unit of a dynamic viscoelasticity tester. Specifically, as shown in FIG. 1, an asphalt composition 1 is sandwiched between two parallel disks 2a and 2b, a sine wave distortion of a predetermined frequency is applied to one disk 2a, and the asphalt composition 1 is passed through the asphalt composition 1. The phase difference δ between the sinusoidal stress σ transmitted to the other disk 2b and the sine wave input to the disk 2a and the gain sine wave obtained from the disk 2b is measured. The measurement conditions at that time are as follows: when the measurement temperature is 60 ° C., the diameter of the disks 2a and 2b is 25 mm, the thickness of the measurement asphalt composition 1 is 1 mm, the strain is 10%, and the measurement temperature is 10 ° C. The diameters of the disks 2a and 2b are 8 mm, the thickness of the measured asphalt composition 1 is 2 mm, and the strain is 1%. And based on the measurement result, storage shear elastic modulus G 'is calculated | required from following Numerical formula (1). Here, γ in the following mathematical formula (1) is the maximum strain applied to the disk 2a.

  Examples of a method for bringing the storage shear modulus of the asphalt composition at 10 ° C. and 60 ° C. into the above-described range include, for example, the amount of the thermoplastic elastomer in the asphalt composition, and the amount of asphalt or a mixture of asphalt and petroleum solvent extract oil. A method of adjusting the amount is mentioned. Thermoplastic elastomers have the effect of reducing temperature dependence in the viscoelastic properties of asphalt compositions. For this reason, the storage shear elastic modulus of an asphalt composition can be made into the above-mentioned range by adjusting the mixing ratio of a thermoplastic elastomer and asphalt. However, when the thermoplastic elastomer content per total mass of the asphalt composition is less than 8% by mass, the temperature dependence of the storage shear elastic modulus increases, especially the storage shear coefficient decreases at the high temperature side, and the storage shear at 60 ° C. The coefficient may be small. On the other hand, when the content of the plastic elastomer exceeds 14% by mass, the storage shear coefficient on the low temperature side may be decreased, the storage shear coefficient at 10 ° C. may be decreased, and the thermal stability of the adhesive performance is decreased. Sometimes. Therefore, the thermoplastic elastomer content is desirably 8 to 14% by mass.

  Examples of the thermoplastic elastomer added to the asphalt composition of the present invention include styrene-butadiene-styrene copolymer (SBS), styrene-isoprene-styrene copolymer (SIS), styrene-ethylene-butylene- Examples thereof include styrene copolymer (SEBS) and styrene-ethylene-propylene-styrene copolymer (SEPS). Among these thermoplastic elastomers, in particular, pressure-sensitive adhesive production temperature and processing temperature (180 to 200). It is desirable to use SBS, which is an elastomer that is less expensive than the hydrogenated thermoplastic elastomer described later, and has a small decrease in the storage shear elastic modulus due to decomposition at about 0 ° C.). In addition, you may add the hydrogenated thermoplastic elastomer obtained by hydrogenating SBS and SIS as a thermoplastic elastomer to the asphalt composition of this invention. Thereby, the elastic property change at the time of a process can further be reduced, and the stable property can be implement | achieved.

  On the other hand, asphalt used in the asphalt composition of the present invention, for example, straight asphalt (see JIS K 2207), solvent deasphalted asphalt ("New Petroleum Dictionary", edited by the Japan Petroleum Institute, 1982, p. 308), Or a mixture thereof or the like can be mentioned. Petroleum-based solvent extraction oil is an oil extracted during the solvent extraction process when producing lubricating oil from crude oil, and is an oily substance rich in aromatics and naphthenes (" 6-1 “General Lubricating Oil Manufacturing Process”, published by Japan Federation of Petroleum, November 1971, p. 99, and “New Petroleum Dictionary”, Petroleum Society, 1982, p. 304). This petroleum solvent extracted oil is a component that acts as a softener when added to an asphalt composition, has a boiling point of 350 ° C. or higher, a viscosity at 100 ° C. of 5 to 100 mPa · sec, and a flash point of 250 ° C. or higher. Thus, the aromatic content is desirably 75% by mass or more. Examples of such petroleum solvent extraction oil include bright stock solvent extractables extracted with a solvent such as phenol, N-methylpyrrolidone, liquid sulfur dioxide, and furfural in a crude oil refining process.

  In addition, when the content of petroleum-based solvent extracted oil in the asphalt composition exceeds 60% by mass, the composition may be too soft and a storage shear elastic modulus at 60 ° C. may not be ensured. For this reason, when adding petroleum solvent extraction oil, it is desirable to make content in an asphalt composition 60 mass% or less.

Total acid value : 1.5 mgKOH / g or more The total acid value is a value influenced by the number of polar groups contained in the asphalt composition. Specifically, when the total acid value is less than 1.5 mgKOH / g, the number of polar groups in the asphalt composition decreases, and the adherend having a large number of polar groups such as wood, stone, concrete, and non-woven fabric is used. At the time of adhesion, it is not possible to expect an increase in adhesion due to hydrogen bonding. Therefore, in the asphalt composition of this invention, it is 1.5 mgKOH / g or more. The upper limit of the total acid value is not particularly limited, but if it exceeds 12 mgKOH / g, a large amount of fatty acid having a low storage shear modulus is blended, and the entire asphalt composition is stored at 60 ° C. The coefficient may not be secured. Therefore, the total acid value is desirably 12 mgKOH / g or less. Moreover, the total acid value prescribed | regulated in this invention was measured based on the method prescribed | regulated by JISK0070 (The test method of the acid value of a chemical product, a saponification value, an iodine value, a hydroxyl value, and an unsaponifiable substance). Is the time value.

  As a method of bringing the total acid value of the asphalt composition into the above-described range, for example, there is a method of adding a predetermined amount of an organic acid such as a resin acid. The resin acid is an organic acid present in the natural resin as a free or ester, and has an effect of improving the adhesive strength of the asphalt composition. However, when the resin acid content is less than 1% by mass, the acid value may be insufficient, and when the resin acid content exceeds 5% by mass, the storage shear modulus at 60 ° C. may be decreased. . Therefore, when adding a resin acid in an asphalt composition, it is desirable to make the content into 1-5 mass%. Examples of the resin acid added to the asphalt composition of the present invention include rosin, disproportionated rosin, dimer acid or trimer acid originating from abietic acid, or a mixture thereof. Since these resin acids are easily dissolved and dispersed in asphalt, it is possible to eliminate the unevenness and distribution of the acid value in the asphalt composition.

As described above in detail, in the asphalt composition of the present invention, the storage shear elastic modulus at 10 ° C. at a measurement frequency of 6.28 rad / sec is set to 1 × 10 ⁵ Pa or less and the measurement frequency is 6.28 rad / sec. The storage shear elastic modulus at 60 ° C. at 4 × 10 ³ Pa or more and the total acid value at 1.5 mgKOH / g or more, the temperature dependence of the adhesiveness of the asphalt composition is reduced. Excellent adhesiveness can be expressed in a temperature range of ˜50 ° C. As a result, it can be used throughout the year even in outdoor construction.

  Next, the adhesive sheet in which the adhesive layer which consists of an asphalt composition of this invention was provided in the one surface of the base material is demonstrated. As the base material in the pressure-sensitive adhesive sheet of the present invention, for example, non-woven fabric, cloth, paper, plastic sheet, metal thin film and wire mesh can be used. Among these base materials, the non-woven fabric is impregnated with an asphalt composition. Since it is easy, it is desirable to use a nonwoven fabric as a base material. The method for forming the adhesive layer on one surface of the substrate is not particularly limited, and the asphalt composition can be applied, sprayed or impregnated on the substrate by a known method.

The pressure-sensitive adhesive sheet of the present invention has a storage shear elastic modulus at 10 ° C. of 1 × 10 ⁵ Pa or less and a storage shear elastic modulus at 60 ° C. of 4 × 10 ³ Pa when the measurement frequency is 6.28 rad / sec. And since the asphalt composition whose total acid value is 1.5 mgKOH / g or more is used, the temperature dependence of an adhesion layer is small and the outstanding adhesiveness is obtained in the temperature range of 5-50 degreeC. As a result, even if used outdoors, it can be used throughout the year without causing peeling and peeling due to insufficient adhesion. For this reason, this adhesive sheet is suitable for a waterproof sheet used outdoors, such as a waterproof sheet for rooftops, a waterproof sheet for civil engineering, and a waterproof and moistureproof sheet for houses.

  In addition, the asphalt composition of the present invention can be used not only for the above-mentioned pressure-sensitive adhesive sheet, but also as a single pressure-sensitive adhesive, and as a road pavement material, repair material, filler, etc., utilizing high adhesive performance. Can also be used.

Hereinafter, the effects of the present invention will be specifically described with reference to Examples and Comparative Examples. In this example, asphalt, petroleum solvent extracted oil, thermoplastic elastomer and resin acid were mixed in the proportions shown in Table 1 below to prepare asphalt compositions of Examples and Comparative Examples. The mixing conditions at that time were a mixing temperature of 170 ° C., a mixing time of 120 minutes, and a mixer rotation speed of 3000 times / minute. Further, in this example, asphalt has a penetration at 25 ° C. of 8 (1/10 mm), a softening point of 66.5 ° C., a density at 15 ° C. of 1028 kg / m ³ , a flash point of 352 ° C., An aromatic component having a mass of 61% by mass and an asphaltene content of 14% by mass was used. The petroleum-based solvent extracted oil has a viscosity at 100 ° C. of 0.060 Pa · sec, a density at 15 ° C. of 974.2 kg / m ³ , a flash point of 325 ° C., an aromatic content of 81% by mass, and an asphaltene content of 0.1. 90% by mass was used. As the thermoplastic elastomer, SBS containing 31% by mass of styrene, having a density of 940 kg / m ³ , and having a viscosity of 20 Pa · sec at 25 ° C. when used as a 25% by mass toluene solution was used. Further, the resin acid A in Table 1 below is a disproportionated rosin having an acid value of 160 mgKOH / g, the resin acid B is a mixture of dimer acid and trimer acid of abietic acid, and the acid value thereof is 180 mgKOH / g. . In addition, the underline in following Table 1 shows that it is outside the scope of the present invention.

  Next, the total acid value in the asphalt compositions of each Example and Comparative Example shown in Table 1 above, and the storage shear modulus at 10 ° C. and 60 ° C. at a measurement frequency of 6.28 rad / sec were measured. At that time, the total acid value was measured by a method defined in JIS K 0070. The storage shear modulus at 10 ° C. and 60 ° C. was measured by the method described above using a dynamic viscoelasticity tester (ARES) manufactured by TA Instruments. The results are also shown in Table 1 above.

And the adhesive sheet was produced using the asphalt composition of each Example and a comparative example, and the adhesiveness was evaluated by peel strength. 2 is a perspective view showing a method for measuring peel strength, FIG. 3A is a cross-sectional view of the test piece, and FIG. 3B is an enlarged cross-sectional view showing a part of the test piece. Specifically, as shown in FIGS. 2 and 3, 0.5 kg / m ² of each asphalt composition 1 of the example or the comparative example is impregnated on one surface of the polyester nonwoven fabric 3 having a basis weight of 55 g / m ^2. The same non-woven polyester fabric as that used as the base material was pasted on the pressure-sensitive adhesive layer side to prepare a test piece 4 having a width of 40 mm. At that time, the non-woven fabric impregnated with the asphalt composition and the non-woven fabric for laminating were cured for 2 hours in the thermostatic bath set to the test temperature. did. And using this test piece 4, the 180 degree peel test was implemented based on JISK6854-3 (peeling adhesive strength test method-3rd part: T-shaped peeling). The test conditions at that time were a material temperature and a test temperature of 5 to 55 ° C., a tensile speed of 200 mm / min, and a time from adhesion to the start of the test of 2 minutes. Then, three 180 ° peel tests were performed under the above conditions, and the average peel strength obtained was 1.0 N / cm or more at 5 ° C. and 0.5 N / cm or more at 55 ° C. did. The above results are shown in Table 2 below. In addition, each sample measured this time has a peak in the peel strength in the temperature range of 5 to 55 ° C, and the peel strength is higher than 5 ° C or 55 ° C in the temperature range of more than 5 ° C and less than 55 ° C. In Table 2 below, only the peel strength at 5 ° C. and 55 ° C. is shown.

As shown in Table 2 above, the asphalt composition of Comparative Example 1 having a total acid value of less than 1.5 mg KOH / g has a storage shear elastic modulus at 10 ° C. of 1 × 10 ⁵ Pa or less and storage at 60 ° C. Despite the shear modulus of 4 × 10 ³ Pa or more, the peel strength at 55 ° C. was low. Moreover, the asphalt compositions of Comparative Example 2 and Comparative Example 3 having a storage shear elastic modulus at 10 ° C. exceeding 1 × 10 ⁵ Pa had low peel strength at both 5 ° C. and 55 ° C. Furthermore, the asphalt composition of Comparative Example 4 having a storage shear elastic modulus at 60 ° C. of less than 4 × 10 ³ Pa had a low peel strength at 5 ° C.

In contrast, when the measurement frequency is 6.28 rad / sec within the scope of the present invention, the storage shear elastic modulus at 10 ° C. is 1 × 10 ⁵ Pa or less, and the storage shear elastic modulus at 60 ° C. is 4 ×. Each of the asphalt compositions of Examples 1 to 3 having 10 ³ Pa and a total acid value of 1.5 mgKOH / g or more has a peel strength at 5 ° C of 1.0 N / cm or more and 55 ° C. It has been confirmed that the peel strength is 0.5 N / cm or more and has an excellent adhesive force in a wide temperature range, and can be used as a pressure-sensitive adhesive in both summer and winter.

It is a perspective view which shows typically the measurement part of a dynamic viscoelasticity testing machine. It is a perspective view which shows the measuring method of peel strength. (A) is sectional drawing of the test piece shown in FIG. 2, (b) is an expanded sectional view which shows a part of test piece.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Asphalt composition 2a, 2b Disc 3 Nonwoven fabric 4 Test piece

Claims (4)

When the measurement frequency is 6.28 rad / sec, the storage shear elastic modulus at 10 ° C. is 1 × 10 ⁵ Pa or less, the storage shear elastic modulus at 60 ° C. is 4 × 10 ³ Pa or more, and the total acid value is 1. Asphalt composition characterized by being 5 mgKOH / g or more.   The asphalt composition according to claim 1, wherein the total acid value is 12 mgKOH / g or less.   An adhesive sheet comprising an adhesive layer comprising the asphalt composition according to claim 1 or 2 provided on one surface of a substrate.   The pressure-sensitive adhesive sheet according to claim 3, wherein the substrate is a nonwoven fabric.

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